2.A.1 The Major Facilitator Superfamily (MFS)

The MFS is a very old, large and diverse superfamily that includes millions of sequenced members. They catalyze uniport, solute:cation (H+, but seldom Na+) symport and/or solute:H+ or solute:solute antiport. Most are of 400-600 amino acyl residues in length and possess either 12, 14, or occasionally, 24 transmembrane α-helical spanners (TMSs). The mechanistic principles applicable to all MFS carriers have been summarized by Law et al (2008), while Zhang et al. 2015 considered the interaction between protonation and the negative-inside membrane potential. Functional roles of the conserved sequence motifs were also discussed in the context of the 3D structures. Transporters can be modified posttranslationally by phsophorylation, ubiquitination, glycosylation and/or palmitoylation (Czuba et al. 2018). The mammalian proteins have been analyzed from phylogenetic standpoints, revealing three major groups with differing conserved residues (Jia et al. 2019). Proteins of different topologies were also identified. Hu et al. 2020 reviewed the main substrates and functions of SLCs that are expressed in the brain, with an emphasis on selected SLCs that are important physiologically, pathologically, and pharmacologically in the blood-brain barrier, astrocytes, and neurons. The glucose (hexose) transporters, GLUTs, TC# 2.A.1.1, have been reviewed (Holman 2020; Ismail and Tanasova 2022). Single-molecule FRET studies of membrane transport proteins has revealed their conformational flexibilities (Löw et al. 2021). All MFS porters have the MFS fold (Ferrada and Superti-Furga 2022). Anagnostakis et al. 2023 discuss the key structural and functional characteristics of SLC family members involved in glioma pathogenesis, and active ion transmembrane transporter activities were overrepresented in patients with Alzheimer's disease (D'Angiolini et al. 2023). Similarly, Parkinson's disease involves activation of ion transporters via the Leucine Rich Repeat Kinase 2 (LRRK2) in miroglia of mice (Nazish et al. 2023).  Differentially expressed SLC transcripts in phagocytes (macrophages, dendritic cells, and neutrophils) have been identified, compared to adaptive immune cells; new potential immune cell markers based on SLC expressionhave been revealed; and user-friendly online tools for researchers to explore SLC genes of interesthave been created (Aaes et al. 2023). The motions of transport systems have been documented (Loland et al. 2023). 

.The 24 TMS MFS permease, NarK, of Paracoccus pantotrophus has two 12 TMS domains, NarK1 and NarK2, both of which are required for normal nitrate uptake. NarK1 catalyzes NO3-:H+ symport, dependent on the pmf, while NarK2 catalyzes NO3-:NO2- antiport, independently of the pmf (Wood et al., 2002). Thus, the protein is a fusion protein of two homologous but distinct MFS permeases.  Various mechanisms for importing sugars needed to create cellular homeostasis and survival in several kinds of cells have been reviewed (Carbó and Rodríguez 2023).

MFS permeases exhibit specificity for sugars, polyols, drugs, neurotransmitters, Krebs cycle metabolites, phosphorylated glycolytic intermediates, amino acids, peptides, osmolites, siderophores (efflux), iron-siderophores (uptake), nucleosides, organic anions, inorganic anions, etc. They are found ubiquitously in all three kingdoms of living organisms. Among the yeast MFS MDR transporters, the DHA2 family (TC 2.A.1.3) is more variable between species than the DHA1 family (TC 2.A.1.2) (Gbelska et al. 2006). Genome-wide analysis of 40 Major Facilitator Superfamily members and their expression in response of poplar to Fusarium oxysporum infection has been published (Diao et al. 2021). Nano-targeted delivery systems have been created to overcome the main drawbacks of conventional drug treatment, including insufficient stability and solubility, lack of transmembrane transport, short circulation time, and undesirable toxic effects. These systems have been reviewed (Cheng et al. 2023).

One member of the DHA2 family with 14 TMSs, the TetL Me2+· tetracycline:H+ antiporter of B. subtilis (TC #2.A.1.3.16), which also exhibits monovalent ion antiport activity, can be converted to a monovalent cation (Na+, K+, H+) antiporter with no tetracycline transport activity by deletion of TMSs 7 and 8, the two central and extra TMSs (Jin et al., 2001). Genome analyses of MFS permeases have been published (Lorca et al., 2007).

A 6.5 Å resolution structure for the MFS permease, OxlT (TC #2.A.1.11.1) was obtained in early studies (Heymann et al., 2001; Hirai et al., 2002) which shows the positions of the transmembrane α-helices but does not allow assignment of the TMS # to these helices. Molecular modeling (Hirai et al., 2003) led to the suggestion that the 12 TMS protein arose from a 3 TMS element by two successive duplication events. The same suggestion resulted from sequence comparisons showing that the primordial 3 TMS element may have arisen from a VIC family (TC #1.A.1) 2 TMS channel-forming unit Hvorup & Saier, (2002).This conclusion has been extensively confirmed in several more recent studies.

The high-resolution 3-dimensional structures (3.3 and 3.5 Å resolution) of the glycerol-3-P:P antiporter (GlpT; TC #2.A.1.4.3) and the lactose:H+ symporter (LacY; TC #2.A.1.5.1), respectively (Huang et al., 2003 and Abramson et al., 2003, respectively; see also Locher et al., 2003; Guan et al., 2007) have been determined. These structures reveal the 2-fold symmetry expected, based on sequence similarity of the two halves. The substrate pathway is predicted to exist between the two halves of the permeases using an alternating access mechanism with a single substrate binding site (Huang et al., 2003). This mechanism is termed a 'rocker switch' type of movement. Several putative mechanisms involving MFS and other types of transporters underly etridiazole (EDZ)-induced developmental deformities in Zebrafish (Vasamsetti et al. 2023).

As suggested above, MFS symporters and antiporters are believed to operate via a single binding site, alternating-access mechanism that involves a rocker-switch type movement of the two halves of the protein (Law et al., 2008). In the sn-glycerol-3-phosphate transporter (GlpT) from Escherichia coli, the substrate-binding site is formed by several charged residues and a histidine that can be protonated. Salt-bridge formation and breakage are involved in the conformational changes of the protein during transport (Law et al., 2008).

Vesicular glutamate transporters (VGLUTs [2.A.1.14.13, 2.A.1.14.16, etc.]) are responsible for the vesicular storage of L-glutamate and play an essential role in glutamatergic signal transmission in the central nervous system. VGLUT2 facilitates L-glutamate uptake in a membrane potential (ΔΨ)-dependent fashion. Uptake exhibited an absolute requirement for ~4 mM Cl- and was sensitive to Evans blue, but was insensitive to D,L-aspartate. VGLUT2s with mutations in the transmembrane-located residues Arg184, His128, and Glu191 showed a dramatic loss in L-glutamate transport activity. VGLUT2 appears to possess two intrinsic transport machineries that are independent of each other: a ΔΨ-dependent L-glutamate uptake and a Na+-dependent Pi uptake (Juge et al., 2006). VGLUTs (TC# 2.A.1.14) and EAATs (TC# 2.A.23.2) may be potential targets in the treatment of Parkinson's Disease (PD). VGLUTs and EAATs can be used as clinical drug targets to achieve better efficacy (Li et al. 2021).

Trichoderma spp. are avirulent, fungal, opportunistic plant symbionts present in nearly all climatic soils. These Trichoderma strains produce secondary metabolites that are potent bio-control agents against microbial pathogens and also can be plant growth promoters. The MFS includes a large proportion of efflux-pumps which are linked with membrane transport of these secondary metabolites in T. reesei (Chaudhary et al. 2016). Many of these export drugs such an anticancer agents and antibiotics.  A comprehensive review of the classes of efflux pump inhibitors from various sources, highlighting their structure-activity relationships, which can be useful for medicinal chemists in the pursuit of novel efflux pump inhibitors has appeared (Durães et al. 2018).

The generalized transport reactions catalyzed by MFS porters are:

(1) Uniport: S (out) ⇌ S (in)

(2) Symport: S (out) + [H+ (or Na+)] (out) ⇌ S (in) + [H+ (or Na+)] (in)

(3) Antiport: S1 (out) + S2 (in) ⇌ S1 (in) + S2 (out) (S1 may be H+ or a solute)

This family belongs to the Major Facilitator (MFS) Superfamily.



Aaes, T.L., J. Burgoa Cardás, and K.S. Ravichandran. (2023). Defining solute carrier transporter signatures of murine immune cell subsets. Front Immunol 14: 1276196.

Abbas, A., J.E. McGuire, D. Crowley, C. Baysse, M. Dow, and F. O'Gara. (2004). The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance. Microbiology 150: 2443-2450.

Abdel-Motaal, H., L. Meng, Z. Zhang, A.H. Abdelazez, L. Shao, T. Xu, F. Meng, S. Abozaed, R. Zhang, and J. Jiang. (2018). An Uncharacterized Major Facilitator Superfamily Transporter From Exhibits Dual Functions as a Na(Li, K)/H Antiporter and a Multidrug Efflux Pump. Front Microbiol 9: 1601.

Abdulhussein AA. and Wallace HM. (2014). Polyamines and membrane transporters. Amino Acids. 46(3):655-60.

Abplanalp, J., E. Laczko, N.J. Philp, J. Neidhardt, J. Zuercher, P. Braun, D.F. Schorderet, F.L. Munier, F. Verrey, W. Berger, S.M. Camargo, and B. Kloeckener-Gruissem. (2013). The cataract and glucosuria associated monocarboxylate transporter MCT12 is a new creatine transporter. Hum Mol Genet 22: 3218-3226.

Abramson, J., I. Smirnova, V. Kasho, G. Verner, H.R. Kaback, and S. Iwata. (2003). Structure and mechanism of the lactose permease of Escherichia coli. Science 301: 610-615.

AbuAli, G. and S. Grimm. (2014). Isolation and Characterization of the Anticancer Gene Organic Cation Transporter Like-3 (ORCTL3). Adv Exp Med Biol 818: 213-227.

Adeva-Andany, M.M., I. Calvo-Castro, C. Fernández-Fernández, C. Donapetry-García, and A.M. Pedre-Piñeiro. (2017). Significance of l-carnitine for human health. IUBMB Life. [Epub: Ahead of Print]

Adler, J. and E. Bibi. (2004). Determinants of substrate recognition by the Escherichia coli multidrug transporter MdfA identified on both sides of the membrane. J. Biol. Chem. 279: 8957-8965.

Adler, J. and E. Bibi. (2005). Promiscuity in the geometry of electrostatic interactions between the Escherichia coli multidrug resistance transporter MdfA and cationic substrates. J. Biol. Chem. 280: 2721-2729.

Agbani, E.O., L. Skeith, and A. Lee. (2023). Preeclampsia: Platelet procoagulant membrane dynamics and critical biomarkers. Res Pract Thromb Haemost 7: 100075.

Ahmadi, F., S.N. Akmar Abdullah, S. Kadkhodaei, S.M. Ijab, L. Hamzah, M.A. Aziz, Z.A. Rahman, and S.S. Rabiah Syed Alwee. (2018). Functional characterization of the gene promoter for an Elaeis guineensis phosphate starvation-inducible, high affinity phosphate transporter in both homologous and heterologous model systems. Plant Physiol. Biochem 127: 320-335. [Epub: Ahead of Print]

Ai, P., S. Sun, J. Zhao, X. Fan, W. Xin, Q. Guo, L. Yu, Q. Shen, P. Wu, A.J. Miller, and G. Xu. (2009). Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation. Plant J. 57: 798-809.

Albrecht, S., W. Hartmann, F. Houshdaran, A. Koch, B. Gärtner, D. Prawitt, B.U. Zabel, P. Russo, D. Von Schweinitz, and T. Pietsch. (2004). Allelic loss but absence of mutations in the polyspecific transporter gene BWR1A on 11p15.5 in hepatoblastoma. Int J Cancer 111: 627-632.

Aldahmesh, M.A., A.O. Khan, J.Y. Mohamed, H. Hijazi, M. Al-Owain, A. Alswaid, and F.S. Alkuraya. (2012). Genomic analysis of pediatric cataract in Saudi Arabia reveals novel candidate disease genes. Genet Med 14: 955-962.

Alexander, N.J., S.P. McCormick, and T.M. Hohn. (1999). TRI12, a trichothecene efflux pump from Fusarium sporotrichioides: gene isolation and expression in yeast. Mol. Gen. Genet. 261: 977-984.

Alfonso, A., K. Grundahl, J.R. McManus, J.M. Asbury, and J.B. Rand. (1994). Alternative splicing leads to two cholinergic proteins in Caenorhabditis elegans. J. Mol. Biol. 241: 627-630.

Ali, R.S., M.F. Dick, S. Muhammad, D. Sarver, L. Hou, G.W. Wong, and K.C. Welch, Jr. (2020). Glucose transporter expression and regulation following a fast in the ruby-throated hummingbird,. J Exp Biol 223:.

Allard, K.A., V. K. Viswanathan, and N.P. Cianciotto. (2006). lbtA and lbtB Are Required for Production of the Legionella pneumophila Siderophore Legiobactin. J. Bacteriol. 188: 1351-1363.

Almagro, G., A.M. Viale, M. Montero, F.J. Muñoz, E. Baroja-Fernández, H. Mori, and J. Pozueta-Romero. (2018). A cAMP/CRP-controlled mechanism for the incorporation of extracellular ADP-glucose in Escherichia coli involving NupC and NupG nucleoside transporters. Sci Rep 8: 15509.

Almaguer, C., E. Fisher, and J. Patton-Vogt. (2006). Posttranscriptional regulation of Git1p, the glycerophosphoinositol/glycerophosphocholine transporter of Saccharomyces cerevisiae. Curr. Genet. 50: 367-375.

Alomari, D.Z., A.M. Alqudah, K. Pillen, N. von Wirén, and M.S. Röder. (2021). A Major Facilitator Superfamily Transporter is a putative candidate gene for nutrient mineral (Ca, K, Mg, Mn, P and S) accumulation in bread wheat grains. J Exp Bot. [Epub: Ahead of Print]

Aluri, S. and M. Büttner. (2007). Identification and functional expression of the Arabidopsis thaliana vacuolar glucose transporter 1 and its role in seed germination and flowering. Proc. Natl. Acad. Sci. U.S.A. 104: 2537-2542.

Aluri, S., R. Zhao, A. Fiser, and I.D. Goldman. (2017). Residues in the eighth transmembrane domain of the proton-coupled folate transporter (SLC46A1) play an important role in defining the aqueous translocation pathway and in folate substrate binding. Biochim. Biophys. Acta. [Epub: Ahead of Print]

Aluri, S., R. Zhao, C. Lubout, S.M.I. Goorden, A. Fiser, and I.D. Goldman. (2018). Hereditary folate malabsorption due to a mutation in the external gate of the proton-coupled folate transporter SLC46A1. Blood Adv 2: 61-68.

Aluri, S., R. Zhao, K. Lin, D.S. Shin, A. Fiser, and I.D. Goldman. (2019). Substitutions that lock and unlock the proton-coupled folate transporter (PCFT-SLC46A1) in an inward-open conformation. J. Biol. Chem. [Epub: Ahead of Print]

Alvarez, F.J., and J.B. Konopka. (2007). Identification of an N-acetylglucosamine transporter that mediates hyphal induction in Candida albicans. Mol. Biol. Cell. 18: 965-975.

Alves, R., M. Sousa-Silva, D. Vieira, P. Soares, Y. Chebaro, M.C. Lorenz, M. Casal, I. Soares-Silva, and S. Paiva. (2020). Carboxylic Acid Transporters in Pathogenesis. mBio 11:.

Alves, R., S. Mota, S. Silva, C. F Rodrigues, A.J. P Brown, M. Henriques, M. Casal, and S. Paiva. (2017). The carboxylic acid transporters Jen1 and Jen2 affect the architecture and fluconazole susceptibility of Candida albicans biofilm in the presence of lactate. Biofouling 33: 943-954.

Amahong, K., M. Yan, J. Li, N. Yang, H. Liu, X. Bi, D.A. Vuitton, R. Lin, and G. Lü. (2021). EgGLUT1 Is Crucial for the Viability of Metacestode: A New Therapeutic Target? Front Cell Infect Microbiol 11: 747739.

Ambrose, K.D., R. Nisbet, and D.S. Stephens. (2005). Macrolide efflux in Streptococcus pneumoniae is mediated by a dual efflux pump (mel and mef) and is erythromycin inducible. Antimicrob. Agents Chemother. 49: 4203-4209.

Amilhon, B., E. Lepicard, T. Renoir, R. Mongeau, D. Popa, O. Poirel, S. Miot, C. Gras, A.M. Gardier, J. Gallego, M. Hamon, L. Lanfumey, B. Gasnier, B. Giros, and S. El Mestikawy. (2010). VGLUT3 (vesicular glutamate transporter type 3) contribution to the regulation of serotonergic transmission and anxiety. J. Neurosci. 30: 2198-2210.

Amorese, A.J., E.C. Minchew, M.D. Tarpey, A.T. Readyoff, N.C. Williamson, C.A. Schmidt, S.L. McMillin, E.J. Goldberg, Z.S. Terwilliger, Q.A. Spangenburg, C.A. Witczak, J.J. Brault, E.D. Abel, J.M. McClung, K.H. Fisher-Wellman, and E.E. Spangenburg. (2023). Hypoxia Resistance Is an Inherent Phenotype of the Mouse Flexor Digitorum Brevis Skeletal Muscle. Function (Oxf) 4: zqad012.

Anagnostakis, F., M. Kokkorakis, M. Markouli, and C. Piperi. (2023). Impact of Solute Carrier Transporters in Glioma Pathology: A Comprehensive Review. Int J Mol Sci 24:.

Anderson, P.M., Y.C. Sung, and J.A. Fuchs. (1990). The cyanase operon and cyanate metabolism. FEMS Microbiol. Rev. 7: 247-252.

Anzai, N. and H. Endou. (2011). Urate transporters: an evolving field. Semin Nephrol 31: 400-409.

Anzai, N., H. Miyazaki, R. Noshiro, S. Khamdang, A. Chairoungdua, J.-J. Shin, A. Enomoto, S. Sakamoto, T. Hirata, K. Tomita, Y. Kanai, and H. Endou. (2004). The multivalent PDZ domain-containing protein PDZK1 regulates transport activity of renal urate-anion exchanger URAT1 via its C terminus. J. Biol. Chem. 279: 45942-45950.

Anzai, N., K. Ichida, P. Jutabha, T. Kimura, E. Babu, C.J. Jin, S. Srivastava, K. Kitamura, I. Hisatome, H. Endou, and H. Sakurai. (2008). Plasma urate level is directly regulated by a voltage-driven urate efflux transporter URATv1 (SLC2A9) in humans. J. Biol. Chem. 283: 26834-26838.

AONO, K. (1962). [Studies on protein in gallstone]. Fukuoka Igaku Zasshi 53: 897-926.

Aouameur, R., S. Da Cal, P. Bissonnette, M.J. Coady, and J.Y. Lapointe. (2007). SMIT2 mediates all myo-inositol uptake in apical membranes of rat small intestine. Am. J. Physiol. Gastrointest. Liver. Physiol. 293(6):G1300-G1307.

Aouida, M., R. Poulin, and D. Ramotar. (2010). The human carnitine transporter SLC22A16 mediates high affinity uptake of the anticancer polyamine analogue bleomycin-A5. J. Biol. Chem. 285: 6275-6284.

Araki N., Suzuki T., Miyauchi K., Kasai D., Masai E. and Fukuda M. (201). Identification and characterization of uptake systems for glucose and fructose in Rhodococcus jostii RHA1. J Mol Microbiol Biotechnol. 20(3):125-36.

Arjona, F.J., E. de Vrieze, T.J. Visser, G. Flik, and P.H. Klaren. (2011). Identification and functional characterization of zebrafish solute carrier Slc16a2 (Mct8) as a thyroid hormone membrane transporter. Endocrinology 152: 5065-5073.

Arponen, O., P. Wodtke, F.A. Gallagher, and R. Woitek. (2023). Hyperpolarised C-MRI using C-pyruvate in breast cancer: A review. Eur J Radiol 167: 111058. [Epub: Ahead of Print]

Babu, E., Y. Kanai, A. Chairoungdua, D.K. Kim, Y. Iribe, S. Tangtrongsup, P. Jutabha, Y. Li, N. Ahmed, S. Sakamoto, N. Anzai, S. Nagamori, and H. Endou. (2003). Identification of a novel system L amino acid transporter structurally distinct from heterodimeric amino acid transporters. J. Biol. Chem. 278: 43838-43845.

Bacher, P., S. Giersiefer, M. Bach, C. Fork, E. Schömig, and D. Gründemann. (2009). Substrate discrimination by ergothioneine transporter SLC22A4 and carnitine transporter SLC22A5: gain-of-function by interchange of selected amino acids. Biochim. Biophys. Acta. 1788: 2594-2602.

Bagchi, S., E. Perland, K. Hosseini, J. Lundgren, N. Al-Walai, S. Kheder, and R. Fredriksson. (2020). Probable role for major facilitator superfamily domain containing 6 (MFSD6) in the brain during variable energy consumption. Int J. Neurosci. 130: 476-489.

Bahn, A., Y. Hagos, S. Reuter, D. Balen, H. Brzica, W. Krick, B.C. Burckhardt, I. Sabolic, and G. Burckhardt. (2008). Identification of a New Urate and High Affinity Nicotinate Transporter, hOAT10 (SLC22A13). J. Biol. Chem. 283: 16332-16341.

Bahrenberg, T., E.H. Yardeni, A. Feintuch, E. Bibi, and D. Goldfarb. (2021). Substrate binding in the multidrug transporter MdfA in detergent solution and in lipid nanodiscs. Biophys. J. [Epub: Ahead of Print]

Bai J., Mosley L. and Fralick JA. (2010). Evidence that the C-terminus of OprM is involved in the assembly of the VceAB-OprM efflux pump. FEBS Lett. 584(8):1493-7.

Bailey, T.L., A. Nieto, and P.H. McDonald. (2019). A Nonradioactive High-Throughput Screening-Compatible Cell-Based Assay to Identify Inhibitors of the Monocarboxylate Transporter Protein 1. Assay Drug Dev Technol 17: 275-284.

Baker, J., S.H. Wright, and F. Tama. (2012). Simulations of substrate transport in the multidrug transporter EmrD. Proteins 80: 1620-1632.

Baldwin, S.A. (1993). Mammalian passive glucose transporters: members of an ubiquitous family of active and passive transport proteins. Biochim. Biophys. Acta 1154: 17-49.

Balmaceda-Aguilera C., Martos-Sitcha JA., Mancera JM. and Martinez-Rodriguez G. (2012). Cloning and expression pattern of facilitative glucose transporter 1 (GLUT1) in gilthead sea bream Sparus aurata in response to salinity acclimation. Comp Biochem Physiol A Mol Integr Physiol. 163(1):38-46.

Baltazar, F., C. Pinheiro, F. Morais-Santos, J. Azevedo-Silva, O. Queirós, A. Preto, and M. Casal. (2014). Monocarboxylate transporters as targets and mediators in cancer therapy response. Histol Histopathol 29: 1511-1524.

Bannam, T.L., P.A. Johanesen, C.L. Salvado, S.J. Pidot, K.A. Farrow, and J.I. Rood. (2004). The Clostridium perfringens TetA(P) efflux protein contains a functional variant of the Motif A region found in major facilitator superfamily transport proteins. Microbiology 150: 127-134.

Bansal, A., D. Mallik, D. Kar, and A.S. Ghosh. (2016). Identification of a multidrug efflux pump in Mycobacterium smegmatis. FEMS Microbiol. Lett. [Epub: Ahead of Print]

Bapna, A., L. Federici, H. Venter, S. Velamakanni, B. Luisi, T.P. Fan, and H.W. van Veen. (2007). Two proton translocation pathways in a secondary active multidrug transporter. J. Mol. Microbiol. Biotechnol. 12: 197-209.

Baranova, N. and H. Nikaido. (2002). The baeSR two-component regulatory system activates transcription of the yegMNOB (mdtABCD) transporter gene cluster in Escherichia coli and increases its resistance to novobiocin and deoxycholate. J. Bacteriol. 184: 4168-4176.

Bardaweel, S. and A. Issa. (2022). Exploring the Role of Sodium-Glucose Cotransporter as a New Target for Cancer Therapy. J Pharm Pharm Sci 25: 253-265.

Barton, A., S. Eyre, J. Bowes, P. Ho, S. John, and J. Worthington. (2005). Investigation of the SLC22A4 gene (associated with rheumatoid arthritis in a Japanese population) in a United Kingdom population of rheumatoid arthritis patients. Arthritis Rheum 52: 752-758.

Baruffini, E., P. Goffrini, C. Donnini, and T. Lodi. (2006). Galactose transport in Kluyveromyces lactis: major role of the glucose permease Hgt1. FEMS Yeast Research DOI: 10.1111/j.1364.2006.00107.x.

Basak, D., D. Gamez, and S. Deb. (2023). SGLT2 Inhibitors as Potential Anticancer Agents. Biomedicines 11:.

Basso LR Jr., Gast CE., Mao Y. and Wong B. (2010). Fluconazole transport into Candida albicans secretory vesicles by the membrane proteins Cdr1p, Cdr2p, and Mdr1p. Eukaryot Cell. 9(6):960-70.

Batool, H., B. Zubaida, M.A. Hashmi, and M. Naeem. (2019). Genetic testing of two Pakistani patients affected with rare autosomal recessive Fanconi-Bickel syndrome and identification of a novel SLC2A2 splice site variant. J Pediatr Endocrinol Metab. [Epub: Ahead of Print]

Beasley, F.C., E.D. Vinés, J.C. Grigg, Q. Zheng, S. Liu, G.A. Lajoie, M.E. Murphy, and D.E. Heinrichs. (2009). Characterization of staphyloferrin A biosynthetic and transport mutants in Staphylococcus aureus. Mol. Microbiol. 72: 947-963.

Beaudoin, J., R. Ioannoni, L. López-Maury, J. Bähler, S. Ait-Mohand, B. Guérin, S.C. Dodani, C.J. Chang, and S. Labbé. (2011). Mfc1 is a novel forespore membrane copper transporter in meiotic and sporulating cells. J. Biol. Chem. 286: 34356-34372.

Becker, H.M. and J.W. Deitmer. (2008). Nonenzymatic proton handling by carbonic anhydrase II during H+-lactate cotransport via monocarboxylate transporter 1. J. Biol. Chem. 283: 21655-21667.

Becker, H.M., D. Hirnet, C. Fecher-Trost, D. Sultemeyer, and J.W. Deitmer. (2005). Transport activity of MCT1 expressed in Xenopus oocytes is increased by interaction with carbonic anhydrase. J. Biol. Chem. 280: 39882-39889.

Becker, H.M., M. Klier, and J.W. Deitmer. (2010). Nonenzymatic augmentation of lactate transport via monocarboxylate transporter isoform 4 by carbonic anhydrase II. J. Membr. Biol. 234: 125-135.

Beckham, K.S., J.A. Potter, and S.E. Unkles. (2010). Formate-nitrite transporters: optimisation of expression, purification and analysis of prokaryotic and eukaryotic representatives. Protein Expr Purif 71: 184-189.

Behr, S., L. Fried, and K. Jung. (2014). Identification of a novel nutrient-sensing histidine kinase/response regulator network in Escherichia coli. J. Bacteriol. 196: 2023-2029.

Bellocchio, E.E., R.J. Reimer, R.T. Fremeau, Jr., and R.H. Edwards. (2000). Uptake of glutamate into synaptic vesicles by an inorganic phosphate transporter. Science 289: 957-960.

Benko, Z., C. Fenyvesvolgyi, M. Pesti, and M. Sipiczki. (2004). The transcription factor Pap1/Caf3 plays a central role in the determination of caffeine resistance in Schizosaccharomyces pombe. Mol. Genet. Genomics 271: 161-170.

Bennett, K.M., J. Liu, C. Hoelting, and J. Stoll. (2011). Expression and analysis of two novel rat organic cation transporter homologs, SLC22A17 and SLC22A23. Mol. Cell Biochem 352: 143-154.

Berger, C. and D. Zdzieblo. (2020). Glucose transporters in pancreatic islets. Pflugers Arch. [Epub: Ahead of Print]

Bernal J., Guadano-Ferraz A. and Morte B. (2015). Thyroid hormone transporters--functions and clinical implications. Nat Rev Endocrinol. 11(7):406-17.

Besse A., Peduzzi J., Rebuffat S. and Carre-Mlouka A. (2015). Antimicrobial peptides and proteins in the face of extremes: Lessons from archaeocins. Biochimie. 118:344-55.

Beuming, T. and H. Weinstein. (2005). Modeling membrane proteins based on low-resolution electron microscopy maps: a template for the TM domains of the oxalate transporter OxlT. Protein Eng Des Sel 18: 119-125.

Beylerli, O., G. Sufianova, A. Shumadalova, D. Zhang, and I. Gareev. (2022). MicroRNAs-mediated regulation of glucose transporter (GLUT) expression in glioblastoma. Noncoding RNA Res 7: 205-211.

Bhaskar, B.V., T.M. Babu, N.V. Reddy, and W. Rajendra. (2016). Homology modeling, molecular dynamics, and virtual screening of NorA efflux pump inhibitors of Staphylococcus aureus. Drug Des Devel Ther 10: 3237-3252.

Bianco, M.V., F.C. Blanco, B. Imperiale, M.A. Forrellad, R.V. Rocha, L.I. Klepp, A.A. Cataldi, N. Morcillo, and F. Bigi. (2011). Role of P27 -P55 operon from Mycobacterium tuberculosis in the resistance to toxic compounds. BMC Infect Dis 11: 195.

Bleuel, C., Grosse, C., Taudte, N., Scherer, J., Wesenberg, D., Krauss, G.J., Nies, D.H., and Grass, G. (2005). TolC is involved in enterobactin efflux across the outer membrane of Escherichia coli. J. Bacteriol. 187: 6701-6707.

Bley, C., M. van der Linden, and R.R. Reinert. (2011). mef(A) is the predominant macrolide resistance determinant in Streptococcus pneumoniae and Streptococcus pyogenes in Germany. Int J Antimicrob Agents 37: 425-431.

Bobrov, A.G., O. Kirillina, J.D. Fetherston, M.C. Miller, J.A. Burlison, and R.D. Perry. (2014). The Yersinia pestis siderophore, yersiniabactin, and the ZnuABC system both contribute to zinc acquisition and the development of lethal septicaemic plague in mice. Mol. Microbiol. 93: 759-775.

Boccone, L., S. Mariotti, V. Dessì, D. Pruna, A. Meloni, and G. Loudianos. (2010). Allan-Herndon-Dudley syndrome (AHDS) caused by a novel SLC16A2 gene mutation showing severe neurologic features and unexpectedly low TRH-stimulated serum TSH. Eur J Med Genet 53: 392-395.

Bodoy, S., L. Martin, A. Zorzano, M. Palacín, R. Estévez, and J. Bertran. (2005). Identification of LAT4, a novel amino acid transporter with system L activity. J. Biol. Chem. 280: 12002-12011.

Bohn, C. and P. Bouloc. (1998). The Escherichia coli cmlA gene encodes the multidrug efflux pump Cmr/MdfA and is responsible for isopropyl-β-D-thiogalactopyranoside exclusion and spectinomycin sensitivity. J. Bacteriol. 180: 6072-6075.

Boles, E. and C.P. Hollenberg. (1997). The molecular genetics of hexose transport in yeasts. FEMS Microbiol. Rev. 21: 85-111.

Boonyakanog, A., N. Charoenlap, S. Chattrakarn, P. Vattanaviboon, and S. Mongkolsuk. (2022). Contribution of Stenotrophomonas maltophilia MfsC transporter to protection against diamide and the regulation of its expression by the diamide responsive repressor DitR. PLoS One 17: e0272388.

Boorer, K.J., D.D. Loo, and E.M. Wright. (1994). Steady-state and presteady-state kinetics of the H+/hexose cotransporter (STP1) from Arabidopsis thaliana expressed in Xenopus oocytes. J. Biol. Chem. 269: 20417-20424.

Boot, A., J. Oosting, S. Doorn, S. Ouahoud, M. Ventayol Garcia, D. Ruano, H. Morreau, and T. van Wezel. (2019). Allelic Switching of , , and during Colorectal Cancer Tumorigenesis. Int J Genomics 2019: 1287671.

Bossuyt, X., M. Müller, B. Hagenbuch, and P.J. Meier. (1996). Polyspecific drug and steroid clearance by an organic anion transporter of mammalian liver. J. Pharmacol. Exper. Therapeutics 276: 891-896.

Bost, S., F. Silva, and D. Belin. (1999). Transcriptional activation of ydeA, which encodes a member of the major facilitator superfamily, interferes with arabinose accumulation and induction of the Escherichia coli arabinose PBAD promoter. J. Bacteriol. 181: 2185-2191.

Bozdag, G.O., I. Uluisik, G.S. Gulculer, H.C. Karakaya, and A. Koc. (2011). Roles of ATR1 paralogs YMR279c and YOR378w in boron stress tolerance. Biochem. Biophys. Res. Commun. 409: 748-751.

Braakman, R., M.J. Follows, and S.W. Chisholm. (2017). Metabolic evolution and the self-organization of ecosystems. Proc. Natl. Acad. Sci. USA 114: E3091-E3100.

Braibant, M., J. Chevalier, E. Chaslus-Dancla, J.M. Pagès, and A. Cloeckaert. (2005). Structural and functional study of the phenicol-specific efflux pump FloR belonging to the major facilitator superfamily. Antimicrob. Agents Chemother. 49: 2965-2971.

Brandenstein, L., M. Schweizer, J. Sedlacik, J. Fiehler, and S. Storch. (2015). Lysosomal dysfunction and impaired autophagy in a novel mouse model deficient for the lysosomal membrane protein Cln7. Hum Mol Genet. [Epub: Ahead of Print]

Brickman, T.J. and S.K. Armstrong. (2005). Bordetella AlcS transporter functions in alcaligin siderophore export and is central to inducer sensing in positive regulation of alcaligin system gene expression. J. Bacteriol. 187: 3650-3661.

Brignone, M.S., A. Lanciotti, S. Camerini, C. De Nuccio, T.C. Petrucci, S. Visentin, and E. Ambrosini. (2015). MLC1 protein: a likely link between leukodystrophies and brain channelopathies. Front Cell Neurosci 9: 66.

Brouns, I., I. Pintelon, J. Van Genechten, I. De Proost, J.P. Timmermans, and D. Adriaensen. (2004). Vesicular glutamate transporter 2 is expressed in different nerve fibre populations that selectively contact pulmonary neuroepithelial bodies. Histochem Cell Biol 121: 1-12.

Brown, E., S.P. Rajeev, D.J. Cuthbertson, and J.P.H. Wilding. (2019). A review of the mechanism of action, metabolic profile and haemodynamic effects of sodium-glucose co-transporter-2 inhibitors. Diabetes Obes Metab 21Suppl2: 9-18.

Brown, M.G., E.H. Mitchell, and D.L. Balkwill. (2008). Tet 42, a novel tetracycline resistance determinant isolated from deep terrestrial subsurface bacteria. Antimicrob. Agents Chemother. 52: 4518-4521.

Bukhari, F.J., H. Moradi, P. Gollapudi, H. Ju Kim, N.D. Vaziri, and H.M. Said. (2011). Effect of chronic kidney disease on the expression of thiamin and folic acid transporters. Nephrol Dial Transplant 26: 2137-2144.

Buyse, M., S.V. Sitaraman, X. Liu, A. Bado, and D. Merlin. (2002). Luminal leptin enhances CD147/MCT-1-mediated uptake of butyrate in the human intestinal cell line Caco2-BBE. J. Biol. Chem. 277: 28182-28190.

Cabedo Martinez, A.I., K. Weinhäupl, W.K. Lee, N.A. Wolff, B. Storch, S. Żerko, R. Konrat, W. Koźmiński, K. Breuker, F. Thévenod, and N. Coudevylle. (2016). Biochemical and Structural Characterization of the Interaction between the Siderocalin NGAL/LCN2 (Neutrophil Gelatinase-associated Lipocalin/Lipocalin 2) and the N-terminal Domain of Its Endocytic Receptor SLC22A17. J. Biol. Chem. 291: 2917-2930.

Cabrito, T.R., M.C. Teixeira, A.A. Duarte, P. Duque, and I. Sá-Correia. (2009). Heterologous expression of a Tpo1 homolog from Arabidopsis thaliana confers resistance to the herbicide 2,4-D and other chemical stresses in yeast. Appl. Microbiol. Biotechnol. 84: 927-936.

Cai, H., M. Hauser, F. Naider, and J.M. Becker. (2007). Differential regulation and substrate preferences in two peptide transporters of Saccharomyces cerevisiae. Eukaryot. Cell. 6: 1805-1813.

Calabrese, D., J. Bille, and D. Sanglard. (2000). A novel multidrug efflux transporter gene of the major facilitator superfamily from Candida albicans (FLU1) conferring resistance to fluconazole. Microbiology (Reading) 146(Pt11): 2743-2754.

Calderon-Rivera, A., S. Loya-Lopez, K. Gomez, and R. Khanna. (2022). Plant and fungi derived analgesic natural products targeting voltage-gated sodium and calcium channels. Channels (Austin) 16: 198-215.

Callewaert, B.L., A. Willaert, W.S. Kerstjens-Frederikse, J. De Backer, K. Devriendt, B. Albrecht, M.A. Ramos-Arroyo, M. Doco-Fenzy, R.C. Hennekam, R.E. Pyeritz, O.N. Krogmann, G. Gillessen-kaesbach, E.L. Wakeling, S. Nik-zainal, C. Francannet, P. Mauran, C. Booth, M. Barrow, R. Dekens, B.L. Loeys, P.J. Coucke, and A.M. De Paepe. (2008). Arterial tortuosity syndrome: clinical and molecular findings in 12 newly identified families. Hum Mutat 29(1): 150-158.

Campbell, C.L., C.J. Lehmann, S.S. Gill, W.A. Dunn, A.A. James, and B.D. Foy. (2011). A role for endosomal proteins in alphavirus dissemination in mosquitoes. Insect Mol Biol 20: 429-436.

Cannon, R.D., F.J. Fischer, K. Niimi, M. Niimi, and M. Arisawa. (1998). Drug pumping mechanisms in Candida albicans. Nippon Ishinkin Gakkai Zasshi 39: 73-78.

Cantón, R., A. Mazzariol, M.I. Morosini, F. Baquero, and G. Cornaglia. (2005). Telithromycin activity is reduced by efflux in Streptococcus pyogenes. J Antimicrob Chemother 55: 489-495.

Cao, C., E.K. Pressman, E.M. Cooper, R. Guillet, M. Westerman, and K.O. O'Brien. (2014). Placental heme receptor LRP1 correlates with the heme exporter FLVCR1 and neonatal iron status. Reproduction 148: 295-302.

Carayannopoulos, M.O., A. Schlein, A. Wyman, M. Chi, C. Keembiyehetty, and K.H. Moley. (2004). GLUT9 is differentially expressed and targeted in the preimplantation embryo. Endocrinology 145: 1435-1443.

Carayannopoulos, M.O., M.M. Chi, Y. Cui, J.M. Pingsterhaus, R.A. McKnight, M. Mueckler, S.U. Devaskar, and K.H. Moley. (2000). GLUT8 is a glucose transporter responsible for insulin-stimulated glucose uptake in the blastocyst. Proc. Natl. Acad. Sci. USA 97: 7313-7318.

Carbó, R. and E. Rodríguez. (2023). Relevance of Sugar Transport across the Cell Membrane. Int J Mol Sci 24:.

Carolé, S., S. Pichoff, and J.P. Bouché. (1999). Escherichia coli gene ydeA encodes a major facilitator pump which exports L-arabinose and isopropyl-β-D-thiogalactopyranoside. J. Bacteriol. 181: 5123-5125.

Carter, E.L., L. Jager, L. Gardner, C.C. Hall, S. Willis, and J.M. Green. (2007). Escherichia coli abg genes enable uptake and cleavage of the folate catabolite p-aminobenzoyl-glutamate. J. Bacteriol. 189: 3329-3334.

Cartier, E.A., L.A. Parra, T.B. Baust, M. Quiroz, G. Salazar, V. Faundez, L. Egaña, and G.E. Torres. (2010). A biochemical and functional protein complex involving dopamine synthesis and transport into synaptic vesicles. J. Biol. Chem. 285: 1957-1966.

Cecchetto, G., S. Amillis, G. Diallinas, C. Scazzocchio, and C. Drevet. (2004). The AzgA purine transporter of Aspergillus nidulans: characterization of a protein belonging to a new phylogenetic cluster. J. Biol. Chem. 279: 3132-3141.

Cesareo, R., M. Iozzino, D. Alva, C. Napolitano, B. De Rosa, S. Contini, L. Mallardo, A. Lauria, G. Reda, and A. Orsini. (2007). Evidence based medicine and effective interventions of pharmacological therapy for the prevention of osteoporotic fractures. Minerva Endocrinol 32: 275-295.

Chahboune, A., M. Decaffmeyer, R. Brasseur, and B. Joris. (2005). Membrane topology of the Escherichia coli AmpG permease required for recycling of cell wall anhydromuropeptides and AmpC β-lactamase induction. Antimicrob. Agents Chemother. 49: 1145-1149.

Chahine, S. and M.J. O'Donnell. (2010). Effects of acute or chronic exposure to dietary organic anions on secretion of methotrexate and salicylate by Malpighian tubules of Drosophila melanogaster larvae. Arch Insect Biochem Physiol 73: 128-147.

Chahine, S., A. Campos, and M.J. O''Donnell. (2012). Genetic knockdown of a single organic anion transporter alters the expression of functionally related genes in Malpighian tubules of Drosophila melanogaster. J Exp Biol 215: 2601-2610.

Chahine, S., S. Seabrooke, and M.J. O''Donnell. (2012). Effects of genetic knock-down of organic anion transporter genes on secretion of fluorescent organic ions by Malpighian tubules of Drosophila melanogaster. Arch Insect Biochem Physiol 81: 228-240.

Chaillou, S., Y.C. Bor, C.A. Batt, P.W. Postma, and P.H. Pouwels. (1998). Molecular cloning and functional expression in Lactobacillus plantarum 80 of xylT, encoding the D-xylose-H+ symporter of Lactobacillus brevis. Appl. Environ. Microbiol. 64: 4720-4728.

Chamarthy, S. and J.R. Mekala. (2023). Functional importance of glucose transporters and chromatin epigenetic factors in Glioblastoma Multiforme (GBM): possible therapeutics. Metab Brain Dis 38: 1441-1469.

Chang, H.-K. and G.J. Zylstra. (1999). Characterization of the phthalate permease OphD from Burkholderia cepacia ATCC 17616. J. Bacteriol. 181: 6197-6199.

Chang, J.C., R.V. Wilkening, K.M. Rahbari, and M.J. Federle. (2022). Quorum Sensing Regulation of a Major Facilitator Superfamily Transporter Affects Multiple Streptococcal Virulence Factors. J. Bacteriol. e0017622. [Epub: Ahead of Print]

Chang, R., J. Eriksen, and R.H. Edwards. (2018). The dual role of chloride in synaptic vesicle glutamate transport. Elife 7:.

Chang, Y.C., M.J. Tsai, Y.W. Huang, T.C. Chung, and T.C. Yang. (2011). SmQnrR, a DeoR-type transcriptional regulator, negatively regulates the expression of Smqnr and SmtcrA in Stenotrophomonas maltophilia. J Antimicrob Chemother 66: 1024-1028.

Chardwiriyapreecha, S., M. Shimazu, T. Morita, T. Sekito, K. Akiyama, K. Takegawa, and Y. Kakinuma. (2008). Identification of the fnx1(+) and fnx2(+) genes for vacuolar amino acid transporters in Schizosaccharomyces pombe. FEBS Lett. 582: 2225-2230.

Chasseigneaux, S., V. Cochois-Guégan, L. Lecorgne, M. Lochus, S. Nicolic, C. Blugeon, L. Jourdren, D. Gomez-Zepeda, S. Tenzer, S. Sanquer, V. Nivet-Antoine, M.C. Menet, J.L. Laplanche, X. Declèves, S. Cisternino, and B. Saubaméa. (2024). Fasting upregulates the monocarboxylate transporter MCT1 at the rat blood-brain barrier through PPAR δ activation. Fluids Barriers CNS 21: 33.

Chaudhary, N., I. Kumari, P. Sandhu, M. Ahmed, and Y. Akhter. (2016). Proteome scale census of major facilitator superfamily transporters in Trichoderma reesei using protein sequence and structure based classification enhanced ranking. Gene. [Epub: Ahead of Print]

Chaudhary, N., P. Sandhu, M. Ahmed, and Y. Akhter. (2016). Structural basis of transport function in major facilitator superfamily protein from Trichoderma harzianum. Int J Biol Macromol. [Epub: Ahead of Print]

Chen, D.E., S. Podell, J.D. Sauer, M.S. Swanson, and M.H. Saier. (2008). The phagosomal nutrient transporter (Pht) family. Microbiology. 154: 42-53.

Chen, J., M. Yoshinaga, L.D. Garbinski, and B.P. Rosen. (2016). Synergistic interaction of glyceraldehydes-3-phosphate dehydrogenase and ArsJ, a novel organoarsenical efflux permease, confers arsenate resistance. Mol. Microbiol. 100: 945-953.

Chen, L., P. Jia, Y. Liu, R. Wang, Z. Yin, D. Hu, H. Ning, and Y. Ge. (2023). Fluoride exposure disrupts the cytoskeletal arrangement and ATP synthesis of HT-22 cell by activating the RhoA/ROCK signaling pathway. Ecotoxicol Environ Saf 254: 114718.

Chen, S.Y., C.J. Pan, K. Nandigama, B.C. Mansfield, S.V. Ambudkar, and J.Y. Chou. (2008). The glucose-6-phosphate transporter is a phosphate-linked antiporter deficient in glycogen storage disease type Ib and Ic. FASEB J. 22: 2206-2213.

Chen, W.J., S.Y. Huang, Y.W. Chen, Y.F. Liu, and R.S. Huang. (2023). Dietary Folate Deficiency Promotes Lactate Metabolic Disorders to Sensitize Lung Cancer Metastasis through MTOR-Signaling-Mediated Druggable Oncotargets. Nutrients 15:.

Chenaux, G., L. Matt, T.C. Hill, I. Kaur, X.B. Liu, L.M. Kirk, D.J. Speca, S.A. McMahon, K. Zito, J.W. Hell, and E. Díaz. (2016). Loss of SynDIG1 Reduces Excitatory Synapse Maturation But Not Formation In Vivo. eNeuro 3:.

Cheng, L.C., S. Baboo, C. Lindsay, L. Brusman, S. Martinez-Bartolomé, O. Tapia, X. Zhang, J.R. Yates, 3rd, and L. Gerace. (2019). Identification of new transmembrane proteins concentrated at the nuclear envelope using organellar proteomics of mesenchymal cells. Nucleus 10: 126-143.

Cheng, Q. and J.T. Park. (2002). Substrate specificity of the AmpG permease required for recycling of cell wall anhydro-muropeptides. J. Bacteriol. 184: 6434-6436.

Cheng, X., Q. Xie, and Y. Sun. (2023). Advances in nanomaterial-based targeted drug delivery systems. Front Bioeng Biotechnol 11: 1177151.

Chiabrando, D., L. Scietti, A.G. Prajica, F. Bertino, E. Tolosano, and F. Magnani. (2020). Expression and purification of the heme exporter FLVCR1a. Protein Expr Purif 172: 105637. [Epub: Ahead of Print]

Cho, Y.-H., E.-J. Kim, H.-J. Chung, J.-H. Choi, K.F. Chater, B.-E. Ahn, J.-H. Shin, and Y.-H. Roe. (2003). The pqrAB operon is responsible for paraquat resistance in Streptomyces coelicolor. J. Bacteriol. 185: 6756-6763.

Choquer, M., M.H. Lee, H.J. Bau, and K.R. Chung. (2007). Deletion of a MFS transporter-like gene in Cercospora nicotianae reduces cercosporin toxin accumulation and fungal virulence. FEBS Lett. 581: 489-494.

Chou, J.Y. and B.C. Mansfield. (2014). The SLC37 family of sugar-phosphate/phosphate exchangers. Curr Top Membr 73: 357-382.

Choudhary, A., H. Purohit, and P.S. Phale. (2017). Benzoate transport in Pseudomonas putida CSV86. FEMS Microbiol. Lett. 364:.

Christensen, M., T. Borza, G. Dandanell, A.-M. Gilles, O. Barzu, R.A. Kelln, and J. Neuhard. (2003). Regulation of expression of the 2-deoxy-D-ribose utilization regulon, deoQKPX, from Salmonella enterica serovar typhimurium. J. Bacteriol. 185: 6042-6050.

Clark, T.J., C. Momany, and E.L. Neidle. (2002). The benPK operon, proposed to play a role in transport, is part of a regulon for benzoate catabolism in Acinetobacter sp. strain ADP1. Microbiology 148: 1213-1223.

Clegg, S., F. Yu, L. Griffiths, and J.A. Cole. (2002). The roles of the polytopic membrane proteins NarK, NarU and NirC in Escherichia coli K-12: two nitrate and three nitrite transporters. Mol. Microbiol. 44: 143-155.

Clegg, S.J., W. Jia, and J.A. Cole. (2006). Role of the Escherichia coli nitrate transport protein, NarU, in survival during severe nutrient starvation and slow growth. Microbiology 152: 2091-2100.

Cliburn, R.A., A.R. Dunn, K.A. Stout, C.A. Hoffman, K.M. Lohr, A.I. Bernstein, E.J. Winokur, J. Burkett, Y. Shmitz, W.M. Caudle, and G.W. Miller. (2016). Immunochemical localization of vesicular monoamine transporter 2 (VMAT2) in mouse brain. J Chem Neuroanat. [Epub: Ahead of Print]

Colangeli, R., D. Helb, C. Vilchèze, M.H. Hazbón, C.G. Lee, H. Safi, B. Sayers, I. Sardone, M.B. Jones, R.D. Fleischmann, S.N. Peterson, W.R. Jacobs, Jr, and D. Alland. (2007). Transcriptional regulation of multi-drug tolerance and antibiotic-induced responses by the histone-like protein Lsr2 in M. tuberculosis. PLoS Pathog 3: e87.

Collier, L.S., N.N. Nichols, and E.L. Neidle. (1997). benK encodes a hydrophobic permease-like protein involved in benzoate degradation by Acinetobacter sp. strain ADP1. J. Bacteriol. 179: 5943-5946.

Condemine, G. (2000). Characterization of SotA and SotB, two Erwinia chrysanthemi proteins which modify isopropyl-β-D-thiogalactopyranoside and lactose induction of the Escherichia coli lac promoter. J. Bacteriol. 182: 1340-1345.

Cooper, G.J., B. Leighton, A.C. Willis, and A.J. Day. (1989). The amylin superfamily: a novel grouping of biologically active polypeptides related to the insulin A-chain. Prog Growth Factor Res 1: 99-105.

Costa, C., C. Pires, T.R. Cabrito, A. Renaudin, M. Ohno, H. Chibana, I. Sá-Correia, and M.C. Teixeira. (2013). Candida glabrata drug:H+ antiporter CgQdr2 confers imidazole drug resistance, being activated by transcription factor CgPdr1. Antimicrob. Agents Chemother. 57: 3159-3167.

Costa, C., J. Ribeiro, I.M. Miranda, A. Silva-Dias, M. Cavalheiro, S. Costa-de-Oliveira, A.G. Rodrigues, and M.C. Teixeira. (2016). Clotrimazole Drug Resistance in Candida glabrata Clinical Isolates Correlates with Increased Expression of the Drug:H+ Antiporters CgAqr1, CgTpo1_1, CgTpo3, and CgQdr2. Front Microbiol 7: 526.

Coucke, P.J., A. Willaert, M.W. Wessels, B. Callewaert, N. Zoppi, J. De Backer, J.E. Fox, G.M. Mancini, M. Kambouris, R. Gardella, F. Facchetti, P.J. Willems, R. Forsyth, H.C. Dietz, S. Barlati, M. Colombi, B. Loeys, and A. De Paepe. (2006). Mutations in the facilitative glucose transporter GLUT10 alter angiogenesis and cause arterial tortuosity syndrome. Nat. Genet. 38: 452-457.

Courville, P., M. Quick, and R.J. Reimer. (2010). Structure-function studies of the SLC17 transporter sialin identify crucial residues and substrate-induced conformational changes. J. Biol. Chem. 285: 19316-19323.

Crouch, M.L., M. Castor, J.E. Karlinsey, T. Kalhorn, and F.C. Fang (2008). Biosynthesis and IroC-dependent export of the siderophore salmochelin are essential for virulence of Salmonella enterica serovar Typhimurium. Mol Microbiol 67: 971-983.

Cui, G., M.K. Konciute, L. Ling, L. Esau, J.B. Raina, B. Han, O.R. Salazar, J.S. Presnell, N. Rädecker, H. Zhong, J. Menzies, P.A. Cleves, Y.J. Liew, C.J. Krediet, V. Sawiccy, M.J. Cziesielski, P. Guagliardo, J. Bougoure, M. Pernice, H. Hirt, C.R. Voolstra, V.M. Weis, J.R. Pringle, and M. Aranda. (2023). Molecular insights into the Darwin paradox of coral reefs from the sea anemone Aiptasia. Sci Adv 9: eadf7108.

Cui, H., L. Li, W. Wang, J. Shen, Z. Yue, X. Zheng, X. Zuo, B. Liang, M. Gao, X. Fan, X. Yin, C. Shen, C. Yang, C. Zhang, X. Zhang, Y. Sheng, J. Gao, Z. Zhu, D. Lin, A. Zhang, Z. Wang, S. Liu, L. Sun, S. Yang, Y. Cui, and X. Zhang. (2014). Exome sequencing identifies SLC17A9 pathogenic gene in two Chinese pedigrees with disseminated superficial actinic porokeratosis. J Med Genet 51: 699-704.

Cui, S., H. Xia, T. Chen, Y. Gu, X. Lv, Y. Liu, J. Li, G. Du, and L. Liu. (2020). Cell Membrane and Electron Transfer Engineering for Improved Synthesis of Menaquinone-7 in Bacillus subtilis. iScience 23: 100918. [Epub: Ahead of Print]

Cuív, P.O., P. Clarke, D. Lynch, and M. O'Connell. (2004). Identification of rhtX and fptX, novel genes encoding proteins that show homology and function in the utilization of the siderophores rhizobactin 1021 by Sinorhizobium meliloti and pyochelin by Pseudomonas aeruginosa, respectively. J. Bacteriol. 186: 2996-3005.

Cunningham P. and Naftalin RJ. (2014). Reptation-induced coalescence of tunnels and cavities in Escherichia Coli XylE transporter conformers accounts for facilitated diffusion. J Membr Biol. 247(11):1161-79.

Cunningham, P., Afzal-Ahmed, I., and Naftalin, R.J. (2006). Docking studies show that D-glucose and quercetin slide through the transporter GLUT1. J. Biol. Chem. 281: 5797-5803.

Cura, A.J. and A. Carruthers. (2010). Acute modulation of sugar transport in brain capillary endothelial cell cultures during activation of the metabolic stress pathway. J. Biol. Chem. 285: 15430-15439.

Cushion, M.T., M.S. Collins, T. Sesterhenn, A. Porollo, A.K. Vadukoot, and E.J. Merino. (2016). Functional Characterization of Pneumocystis carinii Inositol Transporter 1. MBio 7:.

Czeredys, M., L. Samluk, K. Michalec, K. Tułodziecka, K. Skowronek, and K.A. Nałęcz. (2013). Caveolin-1 - a novel interacting partner of organic cation/carnitine transporter (octn2): effect of protein kinase C on this interaction in rat astrocytes. PLoS One 8: e82105.

Czuba, L.C., K.M. Hillgren, and P.W. Swaan. (2018). Post-translational modifications of transporters. Pharmacol Ther 192: 88-99.

D''Angiolini, S., M.S. Basile, E. Mazzon, and A. Gugliandolo. (2023). In Silico Analysis Reveals the Modulation of Ion Transmembrane Transporters in the Cerebellum of Alzheimer''s Disease Patients. Int J Mol Sci 24:.

D'Argenio, D.A., A. Segura, W.M. Coco, P.V. Bünz, and L.N. Ornston. (1999). The physiological contribution of Acinetobacter PcaK, a transport system that acts upon protocatechuate, can be masked by the overlapping specificity of VanK. J. Bacteriol. 181: 3505-3515.

da Cunha, A.C., L.S. Gomes, F. Godoy-Santos, F. Faria-Oliveira, J.A. Teixeira, G.M.S. Sampaio, M.J.M. Trópia, I.M. Castro, C. Lucas, and R.L. Brandão. (2019). High-affinity transport, cyanide-resistant respiration, and ethanol production under aerobiosis underlying efficient high glycerol consumption by Wickerhamomyces anomalus. J Ind Microbiol Biotechnol 46: 709-723.

Dagher, F., A. Nickzad, J. Zheng, M. Hoffmann, and E. Déziel. (2021). Characterization of the biocontrol activity of three bacterial isolates against the phytopathogen Erwinia amylovora. Microbiologyopen 10: e1202.

Dahlin, A., E. Geier, S.L. Stocker, C.D. Cropp, E. Grigorenko, M. Bloomer, J. Siegenthaler, L. Xu, A.S. Basile, D.D. Tang-Liu, and K.M. Giacomini. (2013). Gene expression profiling of transporters in the solute carrier and ATP-binding cassette superfamilies in human eye substructures. Mol Pharm 10: 650-663.

Dakal, T.C., R. Kumar, and D. Ramotar. (2017). Structural modeling of human organic cation transporters. Comput Biol Chem 68: 153-163. [Epub: Ahead of Print]

Dang, S., L. Sun, Y. Huang, F. Lu, Y. Liu, H. Gong, J. Wang, and N. Yan. (2010). Structure of a fucose transporter in an outward-open conformation. Nature 467: 734-738.

Darley, P.I., J.A. Hellstern, J.I. Medina-Bellver, S. Marqués, B. Schink, and B. Philipp. (2007). Heterologous expression and identification of the genes involved in anaerobic degradation of 1,3-dihydroxybenzene (resorcinol) in Azoarcus anaerobius. J. Bacteriol. 189: 3824-3833.

Dashtbani-Roozbehani, A., M. Chitsaz, and M.H. Brown. (2023). The role of TMS 12 in the staphylococcal multidrug efflux protein QacA. J Antimicrob Chemother. [Epub: Ahead of Print]

Date, S.S., C.Y. Chen, Y. Chen, and M. Jansen. (2016). Experimentally optimized threading structures of the proton-coupled folate transporter. FEBS Open Bio 6: 216-230.

de Ramón-Carbonell, M., M. López-Pérez, L. González-Candelas, and P. Sánchez-Torres. (2019). Transporter Contributes to Fungicide Resistance and Fungal Virulence during Citrus Fruit Infection. J Fungi (Basel) 5:.

De Zutter JK., Levine KB., Deng D. and Carruthers A. (2013). Sequence determinants of GLUT1 oligomerization: analysis by homology-scanning mutagenesis. J Biol Chem. 288(28):20734-44.

Deng, D., P. Sun, C. Yan, M. Ke, X. Jiang, L. Xiong, W. Ren, K. Hirata, M. Yamamoto, S. Fan, and N. Yan. (2015). Molecular basis of ligand recognition and transport by glucose transporters. Nature 526: 391-396.

Deng, Z., W. Peng, Z. Lu, and M. Fu. (2021). [Cloning and expression pattern of phosphate transporter 1;1 cDNA sequence from Spirodela polyrrhiza]. Sheng Wu Gong Cheng Xue Bao 37: 2474-2482.

Di Daniel, E., M.H. Mok, E. Mead, C. Mutinelli, E. Zambello, L.L. Caberlotto, T.J. Pell, C.J. Langmead, A.J. Shah, G. Duddy, J.N. Kew, and P.R. Maycox. (2009). Evaluation of expression and function of the H+/myo-inositol transporter HMIT. BMC Cell Biol 10: 54.

Diallinas, G. (2017). Transceptors as a functional link of transporters and receptors. Microb Cell 4: 69-73.

Diao, J., S. Li, L. Ma, P. Zhang, J. Bai, J. Wang, X. Ma, and W. Ma. (2021). Genome-Wide Analysis of Major Facilitator Superfamily and Its Expression in Response of Poplar to. Front Genet 12: 769888.

Díaz, E., A. Ferrández, and J.L. García. (1998). Characterization of the hca cluster encoding the dioxygenolytic pathway for initial catabolism of 3-phenylpropionic acid in Escherichia coli K-12. J. Bacteriol. 180: 2915-2923.

Dietvorst, J., J. Londesborough, and H.Y. Steensma. (2005). Maltotriose utilization in lager yeast strains: MTT1 encodes a maltotriose transporter. Yeast 22: 775-788.

Dietvorst, J., K. Karhumaa, M.C. Kielland-Brandt, and A. Brandt. (2010). Amino acid residues involved in ligand preference of the Snf3 transporter-like sensor in Saccharomyces cerevisiae. Yeast 27: 131-138.

Diezemann, A. and E. Boles. (2003). Functional characterization of the Frt1 sugar transporter and of fructose uptake in Kluyveromyces lactis. Curr. Genet. 43: 281-288.

Divito, C.B., K. Steece-Collier, D.T. Case, S.P. Williams, J.A. Stancati, L. Zhi, M.E. Rubio, C.E. Sortwell, T.J. Collier, D. Sulzer, R.H. Edwards, H. Zhang, and R.P. Seal. (2015). Loss of VGLUT3 Produces Circadian-Dependent Hyperdopaminergia and Ameliorates Motor Dysfunction and l-Dopa-Mediated Dyskinesias in a Model of Parkinson''s Disease. J. Neurosci. 35: 14983-14999.

Do, H.Q. and M. Jansen. (2022). Cell-Free Expression of Proton-Coupled Folate Transporter in the Presence of Nanodiscs. Methods Mol Biol 2507: 425-444.

Do, H.Q., C.M. Bassil, E.I. Andersen, and M. Jansen. (2021). Impact of nanodisc lipid composition on cell-free expression of proton-coupled folate transporter. PLoS One 16: e0253184.

Doege, H., A. Schürmann, G. Bahrenberg, A. Brauers, and H.G. Joost. (2000). GLUT8, a novel member of the sugar transport facilitator family with glucose transport activity. J. Biol. Chem. 275: 16275-16280.

Doran, J., C. Walters, V. Kyle, P. Wooding, R. Hammett-Burke, and W.H. Colledge. (2016). Mfsd14a (Hiat1) gene disruption causes globozoospermia and infertility in male mice. Reproduction 152: 91-99.

Dowhan, W. and M. Bogdanov. (2011). Lipid-protein interactions as determinants of membrane protein structure and function. Biochem Soc Trans 39: 767-774.

Du, X., J. Li, M. Li, X. Yang, Z. Qi, B. Xu, W. Liu, Z. Xu, and Y. Deng. (2020). Research progress on the role of type I vesicular glutamate transporter (VGLUT1) in nervous system diseases. Cell Biosci 10: 26.

Duan, P., J. Wu, and G. You. (2011). Mutational analysis of the role of GXXXG motif in the function of human organic anion transporter 1 (hOAT1). Int J Biochem Mol Biol 2: 1-7.

Dube, F., A. Hinas, N. Delhomme, M. Åbrink, S. Svärd, and E. Tydén. (2023). Transcriptomics of ivermectin response in Caenorhabditis elegans: Integrating abamectin quantitative trait loci and comparison to the Ivermectin-exposed DA1316 strain. PLoS One 18: e0285262.

Duffy, S.P., J. Shing, P. Saraon, L.C. Berger, M.V. Eiden, A. Wilde, and C.S. Tailor. (2010). The Fowler syndrome-associated protein FLVCR2 is an importer of heme. Mol. Cell Biol. 30: 5318-5324.

Dumitrescu, A.M., X.H. Liao, T.B. Best, K. Brockmann, and S. Refetoff. (2004). A novel syndrome combining thyroid and neurological abnormalities is associated with mutations in a monocarboxylate transporter gene. Am J Hum Genet 74: 168-175.

Durães, F., M. Pinto, and E. Sousa. (2018). Medicinal Chemistry Updates on Bacterial Efflux Pump Modulators. Curr. Med. Chem. 25: 6030-6069.

Eames, M. and T. Kortemme. (2012). Cost-benefit tradeoffs in engineered lac operons. Science 336: 911-915.

Ebert, K., M. Ewers, I. Bisha, S. Sander, T. Rasputniac, H. Daniel, I. Antes, and H. Witt. (2017). Identification of essential amino acids for glucose transporter 5 (GLUT5)- mediated fructose transport. J. Biol. Chem. [Epub: Ahead of Print]

Egenberger B., Gorboulev V., Keller T., Gorbunov D., Gottlieb N., Geiger D., Mueller TD. and Koepsell H. (2012). A substrate binding hinge domain is critical for transport-related structural changes of organic cation transporter 1. J Biol Chem. 287(37):31561-73.

Ekici, S., H. Yang, H.G. Koch, and F. Daldal. (2012). Novel transporter required for biogenesis of cbb3-type cytochrome c oxidase in Rhodobacter capsulatus. MBio 3:.

Elkins, C.A. and D.C. Savage. (1998). Identification of genes encoding conjugated bile salt hydrolase and transport in Lactobacillus johnsonii 100-100. J. Bacteriol. 180: 4344-4349.

Elkins, C.A. and D.C. Savage. (2003). CbsT2 from Lactobacillus johnsonii 100-100 is a transport protein of the major facilitator superfamily that facilitates bile acid antiport. J. Mol. Microbiol. Biotechnol. 6: 76-87.

Elkins, C.A. and L.B. Mullis. (2006). Mammalian steroid hormones are substrates for the major RND- and MFS-type tripartite multidrug efflux pumps of Escherichia coli. J. Bacteriol. 188: 1191-1195.

Elkins, C.A., S.A. Moser, and D.C. Savage. (2001). Genes encoding bile salt hydrolases and conjugated bile salt transporters in Lactobacillus johnsonii 100-100 and other Lactobacillus species. Microbiology (Reading) 147: 3403-3412.

Ellis, D.A., V. Mustonen, M. Rodríguez-López, C. Rallis, M. Malecki, D.C. Jeffares, and J. Bähler. (2018). Uncovering Natural Longevity Alleles from Intercrossed Pools of Aging Fission Yeast Cells. Genetics. [Epub: Ahead of Print]

Enomoto, A., H. Kumura, A. Chairoungdua, Y. Shigeta, P. Jutabha, S.H. Cha, M. Hosoyamada, M. Takeda, T. Sekine, T. Igarashi, H. Matsuo, Y. Kikuchi, T. Oda, K. Ichida, T. Hosoya, K. Shimokata, T. Niwa, Y. Kanai, and H. Endou. (2002). Molecular identification of a renal urate-anion exchanger that regulates blood urate levels. Nature 417: 447-450.

Enomoto, A., M.F. Wempe, H. Tsuchida, H.J. Shin, S.H. Cha, N. Anzai, A. Goto, A. Sakamoto, T. Niwa, Y. Kanai, M.W. Anders, and H. Endou. (2002). Molecular identification of a novel carnitine transporter specific to human testis. Insights into the mechanism of carnitine recognition. J. Biol. Chem. 277: 36262-36271.

Eraly, S.A., B.A. Hamilton, and S.K. Nigam. (2003). Organic anion and cation transporters occur in pairs of similar and similarly expressed genes. Biochem. Biophys. Res. Commun. 300: 333-342.

Eraly, S.A., J.C. Monte, and S.K. Nigam. (2004). Novel slc22 transporter homologs in fly, worm, and human clarify the phylogeny of organic anion and cation transporters. Physiol Genomics 18: 12-24.

Eraly, S.A., K.T. Bush, R.V. Sampogna, V. Bhatnagar, and S.K. Nigam. (2003). The molecular biology of organic anion transporters: from DNA to FDA? Mol. Pharmacol. in press.

Eraly, S.A., V. Vallon, T. Rieg, J.A. Gangoiti, W.R. Wikoff, G. Siuzdak, B.A. Barshop, and S.K. Nigam. (2008). Multiple organic anion transporters contribute to net renal excretion of uric acid. Physiol Genomics 33: 180-192.

Erb, R.W., K.N. Timmis, and D.H. Pieper DH. (1998). Characterization of a gene cluster from Ralstonia eutropha JMP134 encoding metabolism of 4-methylmuconolactone. Gene. 206: 53-62.

Erickson, J.D., M.K. Schafer, T.I. Bonner, L.E. Eiden, and E. Weihe. (1996). Distinct pharmacological properties and distribution in neurons and endocrine cells of two isoforms of the human vesicular monoamine transporter. Proc. Natl. Acad. Sci. USA 93: 5166-5171.

Ernst, C.M., P. Staubitz, N.N. Mishra, S.J. Yang, G. Hornig, H. Kalbacher, A.S. Bayer, D. Kraus, and A. Peschel. (2009). The bacterial defensin resistance protein MprF consists of separable domains for lipid lysinylation and antimicrobial peptide repulsion. PLoS Pathog 5: e1000660.

Ernst, C.M., S. Kuhn, C.J. Slavetinsky, B. Krismer, S. Heilbronner, C. Gekeler, D. Kraus, S. Wagner, and A. Peschel. (2015). The lipid-modifying multiple Peptide resistance factor is an oligomer consisting of distinct interacting synthase and flippase subunits. MBio 6:.

Erro, R., K.P. Bhatia, A.J. Espay, and P. Striano. (2017). The epileptic and nonepileptic spectrum of paroxysmal dyskinesias: Channelopathies, synaptopathies, and transportopathies. Mov Disord. [Epub: Ahead of Print]

Essand, M., S. Vikman, J. Grawé, L. Gedda, C. Hellberg, K. Oberg, T.H. Totterman, and V. Giandomenico. (2005). Identification and characterization of a novel splicing variant of vesicular monoamine transporter 1. J Mol Endocrinol 35: 489-501.

Evers, M.E., H. Trip, M.A. van den Berg, R.A. Bovenberg, and A.J. Driessen. (2004). Compartmentalization and transport in β-lactam antibiotics biosynthesis. Adv Biochem Eng Biotechnol 88: 111-135.

Fàbrega, A., R.G. Martin, J.L. Rosner, M.M. Tavio, and J. Vila. (2010). Constitutive SoxS expression in a fluoroquinolone-resistant strain with a truncated SoxR protein and identification of a new member of the marA-soxS-rob regulon, mdtG. Antimicrob. Agents Chemother. 54: 1218-1225.

Fan, Y., H. Wang, Z. Yu, Z. Liang, Y. Li, and G. You. (2022). Inhibition of proteasome, but not lysosome, upregulates organic anion transporter 3 in vitro and in vivo. Biochem Pharmacol 208: 115387. [Epub: Ahead of Print]

Fang H., Wu Y., Guo J., Rong J., Ma L., Zhao Z., Zuo D. and Peng S. (2012). T-2 toxin induces apoptosis in differentiated murine embryonic stem cells through reactive oxygen species-mediated mitochondrial pathway. Apoptosis. 17(8):895-907.

Fang, L., J. Hou, Y. Cao, J.J. Shan, and J. Zhao. (2020). Spinster homolog 2 in cancers, its functions and mechanisms. Cell Signal 109821. [Epub: Ahead of Print]

Fang, X., Y. Liu, W. Xiao, N. Zhao, C. Zhu, D. Yu, and Y. Zhao. (2021). Prognostic SLC family genes promote cell proliferation, migration, and invasion in hepatocellular carcinoma. Acta Biochim Biophys Sin (Shanghai) 53: 1065-1075.

Farrow, M.F. and E.J. Rubin. (2008). Function of a mycobacterial major facilitator superfamily pump requires a membrane-associated lipoprotein. J. Bacteriol. 190: 1783-1791.

Farsi, Z., J. Preobraschenski, G. van den Bogaart, D. Riedel, R. Jahn, and A. Woehler. (2016). Single-vesicle imaging reveals different transport mechanisms between glutamatergic and GABAergic vesicles. Science 351: 981-984.

Farwick, A., S. Bruder, V. Schadeweg, M. Oreb, and E. Boles. (2014). Engineering of yeast hexose transporters to transport D-xylose without inhibition by D-glucose. Proc. Natl. Acad. Sci. USA 111: 5159-5164.

Fei, H., T. Karnezis, R.J. Reimer, and D.E. Krantz. (2007). Membrane topology of the Drosophila vesicular glutamate transporter. J Neurochem 101: 1662-1671.

Fernandez-Aguado M., Martin JF., Rodriguez-Castro R., Garcia-Estrada C., Albillos SM., Teijeira F. and Ullan RV. (2014). New insights into the isopenicillin N transport in Penicillium chrysogenum. Metab Eng. 22:89-103.

Fernández-Aguado, M., R.V. Ullán, F. Teijeira, R. Rodríguez-Castro, and J.F. Martín. (2013). The transport of phenylacetic acid across the peroxisomal membrane is mediated by the PaaT protein in Penicillium chrysogenum. Appl. Microbiol. Biotechnol. 97: 3073-3084.

Ferrada, E. and G. Superti-Furga. (2022). A structure and evolutionary-based classification of solute carriers. iScience 25: 105096.

Ferreira, C., F. van Voorst, A. Martins, L. Neves, R. Oliveira, M.C. Kielland-Brandt, C. Lucas, and A. Brandt. (2005). A member of the sugar transporter family, Stl1p is the glycerol/H+ symporter in Saccharomyces cerevisiae. Mol. Biol. Cell 16: 2068-2076.

Ferreira, M.J. and I. Sá-Nogueira. (2010). A multitask ATPase serving different ABC-type sugar importers in Bacillus subtilis. J. Bacteriol. 192: 5312-5318.

Filippo, C.A., O. Ardon, and N. Longo. (2011). Glycosylation of the OCTN2 carnitine transporter: study of natural mutations identified in patients with primary carnitine deficiency. Biochim. Biophys. Acta. 1812: 312-320.

Fiorentino, G., R. Ronca, R. Cannio, M. Rossi, and S. Bartolucci. (2007). MarR-like transcriptional regulator involved in detoxification of aromatic compounds in Sulfolobus solfataricus. J. Bacteriol. 189: 7351-7360.

Fisel P., Stuhler V., Bedke J., Winter S., Rausch S., Hennenlotter J., Nies AT., Stenzl A., Scharpf M., Fend F., Kruck S., Schwab M. and Schaeffeler E. (2015). MCT4 surpasses the prognostic relevance of the ancillary protein CD147 in clear cell renal cell carcinoma. Oncotarget. 6(31):30615-27.

Floyd, J.L., K.P. Smith, S.H. Kumar, J.T. Floyd, and M.F. Varela. (2010). LmrS is a multidrug efflux pump of the major facilitator superfamily from Staphylococcus aureus. Antimicrob. Agents Chemother. 54: 5406-5412.

Fluman, N., D. Cohen-Karni, T. Weiss, and E. Bibi. (2009). A promiscuous conformational switch in the secondary multidrug transporter MdfA. J. Biol. Chem. 284: 32296-32304.

Fomenko, D.E., A.Z. Metlitskaya, J. Péduzzi, C. Goulard, G.S. Katrukha, L.V. Gening, S. Rebuffat, and I.A. Khmel. (2003). Microcin C51 plasmid genes: possible source of horizontal gene transfer. Antimicrob. Agents Chemother. 47: 2868-2874.

Fonseca, M.V., J.D. Sauer, S. Crepin, B. Byrne, and M.S. Swanson. (2014). The phtC-phtD locus equips Legionella pneumophila for thymidine salvage and replication in macrophages. Infect. Immun. 82: 720-730.

Foong, W.E., H.K. Tam, J.J. Crames, B. Averhoff, and K.M. Pos. (2019). The chloramphenicol/H+ antiporter CraA of Acinetobacter baumannii AYE reveals a broad substrate specificity. J Antimicrob Chemother 74: 1192-1201.

Forment, J.V., M. Flipphi, D. Ramón, L. Ventura, and A.P. Maccabe. (2006). Identification of the mstE gene encoding a glucose-inducible, low affinity glucose transporter in Aspergillus nidulans. J. Biol. Chem. 281: 8339-8346.

Fox, V., F. Santoro, G. Pozzi, and F. Iannelli. (2021). Predicted transmembrane proteins with homology to Mef(A) are not responsible for complementing mef(A) deletion in the mef(A)-msr(D) macrolide efflux system in Streptococcus pneumoniae. BMC Res Notes 14: 432.

Franza, T., B. Mahé, and D. Expert. (2005). Erwinia chrysanthemi requires a second iron transport route dependent of the siderophore achromobactin for extracellular growth and plant infection. Mol. Microbiol. 55: 261-275.

Fredriksson, R., S. Sreedharan, K. Nordenankar, J. Alsiö, F.A. Lindberg, A. Hutchinson, A. Eriksson, S. Roshanbin, D.M. Ciuculete, A. Klockars, A. Todkar, M.G. Hägglund, S.V. Hellsten, V. Hindlycke, &.#.1.9.7.;. Västermark, G. Shevchenko, G. Olivo, C. K, K. Kullander, A. Moazzami, J. Bergquist, P.K. Olszewski, and H.B. Schiöth. (2019). The polyamine transporter Slc18b1(VPAT) is important for both short and long time memory and for regulation of polyamine content in the brain. PLoS Genet 15: e1008455. [Epub: Ahead of Print]

Friesema, E.C.H., S. Ganguly, A. Abdalla, J.E. Manning Fox, A.P. Halestrap, and T.J. Visser. (2003). Identification of monocarboxylate transporter 8 as a specific thyroid hormone transporter. J. Biol. Chem. 278: 40128-40135.

Frohlich, K.M. and J.P. Audia. (2013). Dual mechanisms of metabolite acquisition by the obligate intracytosolic pathogen Rickettsia prowazekii reveal novel aspects of triose phosphate transport. J. Bacteriol. 195: 3752-3760.

Fu, D. and P.C. Maloney. (1998). Structure-function relationships in OxlT, the oxalate/formate transporter of Oxalobacter formigenes. Topological features of transmembrane helix 11 as visualized by site-directed fluorescent labeling. J. Biol. Chem. 273: 17962-17967.

Fu, D., R.I. Sarker, K. Abe, E. Bolton, and P.C. Maloney. (2001). Structure/function relationships in OxlT, the oxalate-formate transporter of oxalobacter formigenes. Assignment of transmembrane helix 11 to the translocation pathway. J. Biol. Chem. 276: 8753-8760.

Fujisaki, S., S. Ohnuma, T. Horiuchi, I. Takahashi, S. Tsukui, Y. Nishimura, T. Nishino, M. Kitabatake, and H. Inokuchi. (1996). Cloning of a gene from Escherichia coli that confers resistance to fosmidomycin as a consequence of amplification. Gene 175: 83-87.

Fukuda, M., H. Takeda, H.E. Kato, S. Doki, K. Ito, A.D. Maturana, R. Ishitani, and O. Nureki. (2015). Structural basis for dynamic mechanism of nitrate/nitrite antiport by NarK. Nat Commun 6: 7097.

Fukuhara, S., S. Simmons, S. Kawamura, A. Inoue, Y. Orba, T. Tokudome, Y. Sunden, Y. Arai, K. Moriwaki, J. Ishida, A. Uemura, H. Kiyonari, T. Abe, A. Fukamizu, M. Hirashima, H. Sawa, J. Aoki, M. Ishii, and N. Mochizuki. (2012). The sphingosine-1-phosphate transporter Spns2 expressed on endothelial cells regulates lymphocyte trafficking in mice. J Clin Invest 122: 1416-1426.

Fukui, K., K. Nanatani, M. Nakayama, Y. Hara, M. Tokura, and K. Abe. (2019). Corynebacterium glutamicum CgynfM encodes a dicarboxylate transporter applicable to succinate production. J Biosci Bioeng 127: 465-471.

Furrer, J.L., D.N. Sanders, I.G. Hook-Barnard, and M.A. McIntosh. (2002). Export of the siderophore enterobactin in Escherichia coli: involvement of a 43 kDa membrane exporter. Mol. Microbiol. 44: 1225-1234.

Gaballa, A., M. Cao, and J.D. Helmann. (2003). Two MerR homologues that affect copper induction of the Bacillus subtilis copZA operon. Microbiology 149: 3413-3421.

Galazka, J.M., C. Tian, W.T. Beeson, B. Martinez, N.L. Glass, and J.H. Cate. (2010). Cellodextrin transport in yeast for improved biofuel production. Science 330: 84-86.

Galochkina, T., M. Ng Fuk Chong, L. Challali, S. Abbar, and C. Etchebest. (2019). New insights into GluT1 mechanics during glucose transfer. Sci Rep 9: 998.

Ganapathy, M.E., W. Huang, D.P. Rajan, A.L. Carter, M. Sugawara, K. Iseki, F.H. Leibach, and V. Ganapathy. (2000). β-lactam antibiotics as substrates for OCTN2, an organic cation/carnitine transporter. J. Biol. Chem. 275: 1699-1707.

Gao, H., J. Liang, J. Duan, L. Chen, H. Li, T. Zhen, F. Zhang, Y. Dong, H. Shi, and A. Han. (2021). A Prognosis Marker SLC2A3 Correlates With EMT and Immune Signature in Colorectal Cancer. Front Oncol 11: 638099.

Gao, W., C. Li, F. Wang, Y. Yang, L. Zhang, Z. Wang, X. Chen, M. Tan, G. Cao, and G. Zong. (2023). An efflux pump in genomic island GI-M202a mediates the transfer of polymyxin B resistance in Pandoraea pnomenusa M202. Int Microbiol 1-14. [Epub: Ahead of Print]

Gao, Z., L. Maurousset, R. Lemoine, S.D. Yoo, S. van Nocker, and W. Loescher. (2003). Cloning, expression, and characterization of sorbitol transporters from developing sour cherry fruit and leaf sink tissues. Plant Physiol. 131: 1566-1575.

Garcia, D.L. and J.P. Dillard. (2008). Mutations in ampG or ampD affect peptidoglycan fragment release from Neisseria gonorrhoeae. J. Bacteriol. 190: 3799-3807.

Garcia-Dominguez, M., L. Lopez-Maury, F.J. Florencio, and J.C. Reyes. (2000). A gene cluster involved in metal homeostasis in the cyanobacterium Synechocystis sp. strain PCC 6803. J. Bacteriol. 182: 1507-1514.

Garrido, D., J. Busscher, and A.J. van Tunen. (2006). Promoter activity of a putative pollen monosaccharide transporter in Petunia hybrida and characterisation of a transposon insertion mutant. Protoplasma 228: 3-11.

Gbelska, Y., J.J. Krijger, and K.D. Breunig. (2006). Evolution of gene families: the multidrug resistance transporter genes in five related yeast species. FEMS Yeast Res 6: 345-355.

Geistlinger, K., J.D.R. Schmidt, and E. Beitz. (2023). Human monocarboxylate transporters accept and relay protons via the bound substrate for selectivity and activity at physiological pH. PNAS Nexus 2: pgad007.

George, R.L., X. Wu, W. Huang, Y.J. Fei, F.H. Leibach, and V. Ganapathy. (1999). Molecular cloning and functional characterization of a polyspecific organic anion transporter from Caenorhabditis elegans. J Pharmacol Exp Ther 291: 596-603.

Gerin, I., M. Veiga-da-Cunha, Y. Achouri, J.F. Collet, and E.V. Schaftingen. (1999). Sequence of a putative glucose 6-phosphate translocase, mutated in glycogen storage disease type Ib. Fed. Euro. Biochem. 419: 235-238.

Ghssein, G., C. Brutesco, L. Ouerdane, C. Fojcik, A. Izaute, S. Wang, C. Hajjar, R. Lobinski, D. Lemaire, P. Richaud, R. Voulhoux, A. Espaillat, F. Cava, D. Pignol, E. Borezée-Durant, and P. Arnoux. (2016). Biosynthesis of a broad-spectrum nicotianamine-like metallophore in Staphylococcus aureus. Science 352: 1105-1109.

Girardi, E., A. César-Razquin, S. Lindinger, K. Papakostas, J. Konecka, J. Hemmerich, S. Kickinger, F. Kartnig, B. Gürtl, K. Klavins, V. Sedlyarov, A. Ingles-Prieto, G. Fiume, A. Koren, C.H. Lardeau, R. Kumaran Kandasamy, S. Kubicek, G.F. Ecker, and G. Superti-Furga. (2020). A widespread role for SLC transmembrane transporters in resistance to cytotoxic drugs. Nat Chem Biol 16: 469-478.

Girgis, J., D. Yang, I. Chakroun, Y. Liu, and A. Blais. (2021). Six1 promotes skeletal muscle thyroid hormone response through regulation of the MCT10 transporter. Skelet Muscle 11: 26.

Girin T., El-Kafafi el-S., Widiez T., Erban A., Hubberten HM., Kopka J., Hoefgen R., Gojon A. and Lepetit M. (2010). Identification of Arabidopsis mutants impaired in the systemic regulation of root nitrate uptake by the nitrogen status of the plant. Plant Physiol. 153(3):1250-60.

Goddard, A.D., J.W. Moir, D.J. Richardson, and S.J. Ferguson. (2008). Interdependence of two NarK domains in a fused nitrate/nitrite transporter. Mol. Microbiol. 70: 667-681.

Goffeau, A., J. Park, I.T. Paulsen, J.-L. Jonniaux, T. Dinh, P. Mordant, and M.H. Saier, Jr. (1997). Multidrug resistant transport proteins in yeast. Complete inventory and phylogenetic characterization of yeast open reading frames within the major facilitator superfamily. Yeast 13: 43-54.

Gomez, M. and S.M. Cutting. (1997). Identification of a new sigmaB-controlled gene, csbX, in Bacillus subtilis. Gene 188: 29-33.

Gong, J., C.M. Hutter, P.A. Newcomb, C.M. Ulrich, S.A. Bien, P.T. Campbell, J.A. Baron, S.I. Berndt, S. Bezieau, H. Brenner, G. Casey, A.T. Chan, J. Chang-Claude, M. Du, D. Duggan, J.C. Figueiredo, S. Gallinger, E.L. Giovannucci, R.W. Haile, T.A. Harrison, R.B. Hayes, M. Hoffmeister, J.L. Hopper, T.J. Hudson, J. Jeon, M.A. Jenkins, J. Kocarnik, S. Küry, L. Le Marchand, Y. Lin, N.M. Lindor, R. Nishihara, S. Ogino, J.D. Potter, A. Rudolph, R.E. Schoen, P. Schrotz-King, D. Seminara, M.L. Slattery, S.N. Thibodeau, M. Thornquist, R. Toth, R. Wallace, E. White, S. Jiao, M. Lemire, L. Hsu, U. Peters, and. (2016). Genome-Wide Interaction Analyses between Genetic Variants and Alcohol Consumption and Smoking for Risk of Colorectal Cancer. PLoS Genet 12: e1006296.

Gonzalez, E., E. Flier, D. Molle, D. Accili, and T.E. McGraw. (2011). Hyperinsulinemia leads to uncoupled insulin regulation of the GLUT4 glucose transporter and the FoxO1 transcription factor. Proc. Natl. Acad. Sci. USA 108: 10162-10167.

González-Pasayo, R. and E. Martínez-Romero. (2000). Multiresistance genes of Rhizobium etli CFN42. Mol. Plant-Microbe Interact. 13: 572-577.

Gonzalez-Resines, S., P.J. Quinn, R.J. Naftalin, and C. Domene. (2021). Multiple Interactions of Glucose with the Extra-Membranous Loops of GLUT1 Aid Transport. J Chem Inf Model 61: 3559-3570.

Gora, N., L.J. Weselinski, V.V. Begoyan, A. Cooper, J.Y. Choe, and M. Tanasova. (2023). Discrimination of GLUTs by Fructose Isomers Enables Simultaneous Screening of GLUT5 and GLUT2 Activity in Live Cells. ACS Chem Biol 18: 1089-1100.

Gorboulev, V., N. Shatskaya, C. Volk, and H. Koepsell. (2005). Subtype-specific affinity for corticosterone of rat organic cation transporters rOCT1 and rOCT2 depends on three amino acids within the substrate binding region. Mol Pharmacol 67: 1612-1619.

Gründemann, D., J. Babin-Ebell, F. Martel, N. Ording, A. Schmidt, and E. Schömig. (1997). Primary structure and functional expression of the apical organic cation transporter from kidney epithelial LLC-PK1 cells. J. Biol. Chem. 272: 10408-10413.

Granados, J.C., A. Richelle, J.M. Gutierrez, P. Zhang, X. Zhang, V. Bhatnagar, N.E. Lewis, and S.K. Nigam. (2021). Coordinate regulation of systemic and kidney tryptophan metabolism by the drug transporters OAT1 and OAT3. J. Biol. Chem. 296: 100575.

Gras, C., E. Herzog, G.C. Bellenchi, V. Bernard, P. Ravassard, M. Pohl, B. Gasnier, B. Giros, and S. El Mestikawy. (2002). A third vesicular glutamate transporter expressed by cholinergic and serotoninergic neurons. J. Neurosci. 22: 5442-5451.

Green, A.L., E.J. Anderson, and R.J. Brooker. (2000). A revised model for the structure and function of the lactose permease. J. Biol. Chem. 275: 23240-23246.

Griffith, J.K., D.H. Cuellar, C.A. Fordyce, K.G. Hutchings, and A.A. Mondragon. (1995). Structure and function of the class C tetracycline/H+ antiporter: three independent groups of phenotypes are conferred by TetA (C). Mol. Membr. Biol. 11: 271-277.

Griffith, J.K., M.E. Baker, D.A. Rouch, M.G.P. Page, R.A. Skurray, I.T. Paulsen, K.F. Chater, S.A. Baldwin, and P.J.F. Henderson. (1992). Membrane transport proteins: implications of sequence comparisons. Curr. Opin. Cell Biol. 4: 684-695.

Grijota-Martínez, C., S. Bárez-López, D. Gómez-Andrés, and A. Guadaño-Ferraz. (2020). MCT8 Deficiency: The Road to Therapies for a Rare Disease. Front Neurosci 14: 380.

Groeneweg S., Friesema EC., Kersseboom S., Klootwijk W., Visser WE., Peeters RP. and Visser TJ. (2014). The role of Arg445 and Asp498 in the human thyroid hormone transporter MCT8. Endocrinology. 155(2):618-26.

Groeneweg, S., A. van den Berge, E.C. Lima de Souza, M.E. Meima, R.P. Peeters, and W.E. Visser. (2020). Insights Into the Mechanism of MCT8 Oligomerization. J Endocr Soc 4: bvaa080.

Gronskiy, S.V., N.P. Zakataeva, M.V. Vitushkina, L.R. Ptitsyn, I.B. Altman, A.E. Novikova, and V.A. Livshits. (2005). The yicM (nepI) gene of Escherichia coli encodes a major facilitator superfamily protein involved in efflux of purine ribonucleosides. FEMS Microbiol. Lett. 250: 39-47.

Großhennig, S., S.R. Schmidl, G. Schmeisky, J. Busse, and J. Stülke. (2013). Implication of glycerol and phospholipid transporters in Mycoplasma pneumoniae growth and virulence. Infect. Immun. 81: 896-904.

Grudzinska Pechhacker, M.K., G. Yoon, L.N. Hazrati, J. Maynes, H. MacDonald, E. Tavares, A. Vincent, and E. Heon. (2020). FLVCR1-related disease as a rare cause of retinitis pigmentosa and hereditary sensory autonomic neuropathy. Eur J Med Genet 63: 104037.

Gründling, A. and O. Schneewind. (2007). Genes required for glycolipid synthesis and lipoteichoic acid anchoring in Staphylococcus aureus. J. Bacteriol. 189: 2521-2530.

Guan, L., O. Mirza, G. Verner, S. Iwata, and H.R. Kaback. (2007). Structural determination of wild-type lactose permease. Proc. Natl. Acad. Sci. USA 104: 15294-15298.

Guardia, C.M., X.F. Tan, T. Lian, M.S. Rana, W. Zhou, E.T. Christenson, A.J. Lowry, J.D. Faraldo-Gómez, J.S. Bonifacino, J. Jiang, and A. Banerjee. (2020). Structure of Human ATG9A, the Only Transmembrane Protein of the Core Autophagy Machinery. Cell Rep 31: 107837.

Guillén-Yunta, M., V. Valcárcel-Hernández, &.#.1.9.3.;. García-Aldea, G. Soria, J.M. García-Verdugo, A. Montero-Pedrazuela, and A. Guadaño-Ferraz. (2023). Neurovascular unit disruption and blood-brain barrier leakage in MCT8 deficiency. Fluids Barriers CNS 20: 79.

Guo, H., T. Huang, J. Zhao, H. Chen, and G. Chen. (2018). Fungi short-chain carboxylate transporter: shift from microbe hereditary functional component to metabolic engineering target. Appl. Microbiol. Biotechnol. 102: 4653-4662.

Guo, Y., Z. Ran, Y. Zhang, Z. Song, L. Wang, L. Yao, M. Zhang, J. Xin, and X. Mao. (2020). Marein ameliorates diabetic nephropathy by inhibiting renal sodium glucose transporter 2 and activating the AMPK signaling pathway in db/db mice and high glucose-treated HK-2 cells. Biomed Pharmacother 131: 110684.

Gutiérrez-Preciado, A., A.G. Torres, E. Merino, H.R. Bonomi, F.A. Goldbaum, and V.A. García-Angulo. (2015). Extensive Identification of Bacterial Riboflavin Transporters and Their Distribution across Bacterial Species. PLoS One 10: e0126124.

Guzzo, J. and M.S. Dubow. (2000). A novel selenite- and tellurite-inducible gene in Escherichia coli. Appl. Environ. Microbiol. 66: 4972-4978.

Gyimesi, G. and M.A. Hediger. (2022). Systematic in silico discovery of novel solute carrier-like proteins from proteomes. PLoS One 17: e0271062.

Halestrap, A.P. (2013). Monocarboxylic acid transport. Compr Physiol 3: 1611-1643.

Hamacher, T., J. Becker, M. Gárdonyi, B. Hahn-Hägerdal, and E. Boles. (2002). Characterization of the xylose-transporting properties of yeast hexose transporters and their influence on xylose utilization. Microbiology 148: 2783-2788.

Hampe, I.A.I., J. Friedman, M. Edgerton, and J. Morschhäuser. (2017). An acquired mechanism of antifungal drug resistance simultaneously enables Candida albicans to escape from intrinsic host defenses. PLoS Pathog 13: e1006655.

Hannes, F., P. Hammond, O. Quarrell, J.P. Fryns, K. Devriendt, and J.R. Vermeesch. (2012). A microdeletion proximal of the critical deletion region is associated with mild Wolf-Hirschhorn syndrome. Am J Med Genet A 158A: 996-1004.

Hanschmann EM., Godoy JR., Berndt C., Hudemann C. and Lillig CH. (2013). Thioredoxins, glutaredoxins, and peroxiredoxins--molecular mechanisms and health significance: from cofactors to antioxidants to redox signaling. Antioxid Redox Signal. 19(13):1539-605.

Hansen, M.R., J. Tranekjaer Jørgensen, and G. Dandanell. (2006). Xanthosine utilization in Salmonella enterica serovar Typhimurium is recovered by a single aspartate-to-glycine substitution in xanthosine phosphorylase. J. Bacteriol. 188: 4153-4157.

Harb, J.F., C.L. Christensen, S.H. Kan, A.K. Rha, P. Andrade-Heckman, L. Pollard, R. Steet, J.Y. Huang, and R.Y. Wang. (2023). Base editing corrects the common Salla disease c.115C>T variant. Mol Ther Nucleic Acids 34: 102022.

Hariharan, P., D. Balasubramaniam, A. Peterkofsky, H.R. Kaback, and L. Guan. (2015). Thermodynamic mechanism for inhibition of lactose permease by the phosphotransferase protein IIAGlc. Proc. Natl. Acad. Sci. USA 112: 2407-2412.

Harris, K.G. and C.B. Coyne. (2015). Unc93b Induces Apoptotic Cell Death and Is Cleaved by Host and Enteroviral Proteases. PLoS One 10: e0141383.

Harvat, E.M., Y.M. Zhang, C.V. Tran, Z. Zhang, M.W. Frank, C.O. Rock, and M.H. Saier, Jr. (2005). Lysophospholipid flipping across the Escherichia coli inner membrane catalyzed by a transporter (LplT) belonging to the major facilitator superfamily. J. Biol. Chem. 280: 12028-12034.

Hassan, K.A., A.J. Brzoska, N.L. Wilson, B.A. Eijkelkamp, M.H. Brown, and I.T. Paulsen. (2011). Roles of DHA2 family transporters in drug resistance and iron homeostasis in Acinetobacter spp. J. Mol. Microbiol. Biotechnol. 20: 116-124.

Hassan, K.A., R.A. Skurray, and M.H. Brown. (2007). Transmembrane helix 12 of the Staphylococcus aureus multidrug transporter QacA lines the bivalent cationic drug binding pocket. J. Bacteriol. 189: 9131-9134.

Havukainen, S., J. Pujol-Giménez, M. Valkonen, M.A. Hediger, and C.P. Landowski. (2021). Functional characterization of a highly specific L-arabinose transporter from Trichoderma reesei. Microb Cell Fact 20: 177.

Havukainen, S., M. Valkonen, K. Koivuranta, and C.P. Landowski. (2020). Studies on sugar transporter CRT1 reveal new characteristics that are critical for cellulase induction in. Biotechnol Biofuels 13: 158.

Hawkins, A.C. and C.S. Harwood. (2002). Chemotaxis of Ralstonia eutropha JMP134(pJP4) to the herbicide 2,4-dichlorophenoxyacetate. Appl. Environ. Microbiol. 68: 968-972.

Hayashi, M., K. Tabata, M. Yagasaki, and Y. Yonetani. (2010). Effect of multidrug-efflux transporter genes on dipeptide resistance and overproduction in Escherichia coli. FEMS Microbiol. Lett. 304: 12-19.

Hayashi, T., Y. Tanaka, N. Sakai, U. Okada, M. Yao, N. Watanabe, T. Tamura, and I. Tanaka. (2013). SCO4008, a putative TetR transcriptional repressor from streptomyces coelicolor A3(2), regulates transcription of sco4007 by multidrug recognition. J. Mol. Biol. 425: 3289-3300.

He, E., W. Quan, J. Luo, C. Liu, W. Zheng, and Q. Shen. (2023). Absorption and Transport Mechanism of Red Meat-Derived -glycolylneuraminic Acid and Its Damage to Intestinal Barrier Function through the NF-κB Signaling Pathway. Toxins (Basel) 15:.

He, W., M. Jiang, Y. Li, and X. Ge. (2024). Identification of the Major Facilitator Superfamily Efflux Pump KpsrMFS in That Is Down-Regulated in the Presence of Multi-Stress Factors. Int J Mol Sci 25:.

Heiland, S., N. Radovanovic, M. Höfer, J. Winderickx, and H. Lichtenberg. (2000). Multiple hexose transporters of Schizosaccharomyces pombe. J. Bacteriol. 182: 2153-2162.

Hellborg, L., M. Woolfit, M. Arthursson-Hellborg, and J. Piskur. (2008). Complex evolution of the DAL5 transporter family. BMC Genomics 9: 164.

Henderson, P.J. and R.A. Giddens. (1977). 2-Deoxy-D-galactose, a substrate for the galactose-transport system of Escherichia coli. Biochem. J. 168: 15-22.

Henderson, P.J., R.A. Giddens, and M.C. Jones-Mortimer. (1977). Transport of galactose, glucose and their molecular analogues by Escherichia coli K12. Biochem. J. 162: 309-320.

Hernández-Montalvo, V., F. Valle, F. Bolivar, and G. Gosset. (2001). Characterization of sugar mixtures utilization by an Escherichia coli mutant devoid of the phosphotransferase system. Appl. Microbiol. Biotechnol. 57: 186-191.

Hertz, L. and G.A. Dienel. (2013). Lactate transport and transporters: general principles and functional roles in brain cells. J. Neurosci. Res 79: 11-18.

Heuel, H., A. Shakeri-Garakani, S. Turgut, and J.W. Lengeler. (1998). Genes for D-arabinitol and ribitol catabolism from Klebsiella pneumoniae. Microbiology 144(Pt6): 1631-1639.

Heuel, H., S. Turgut, K. Schmid, and J.W. Lengeler. (1997). Substrate recognition domains as revealed by active hybrids between the D-arabinitol and ribitol transporters from Klebsiella pneumoniae. J. Bacteriol. 179: 6014-6019.

Heymann, J.A.W., R. Sarker, T. Hirai, D. Shi, J.L.S. Milne, P.C. Maloney, and S. Subramaniam. (2001). Projection structure and molecular architecture of OxlT, a bacterial membrane transporter. EMBO J. 20: 4408-4413.

Hiasa, M., T. Miyaji, Y. Haruna, T. Takeuchi, Y. Harada, S. Moriyama, A. Yamamoto, H. Omote, and Y. Moriyama. (2014). Identification of a mammalian vesicular polyamine transporter. Sci Rep 4: 6836.

Higgins, C.F. (2007). Multiple molecular mechanisms for multidrug resistance transporters. Nature 446: 749-757.

Hirabayashi, Y., K.H. Nomura, and K. Nomura. (2013). The acetyl-CoA transporter family SLC33. Mol Aspects Med 34: 586-589.

Hirai, T., J.A.W. Heymann, D. Shi, R. Sarker, P.C. Maloney, and S. Subramaniam. (2002). Three-dimensional structure of a bacterial oxalate transporter. Nature Struct. Biol. 9: 597-600.

Hirai, T., J.A.W. Heymann, P.C. Maloney, and S. Subramaniam. (2003). A structural model for 12-helix transporters belonging to the major facilitator superfamily. J. Bacteriol. 185: 1712-1718.

Hisano, Y., N. Kobayashi, A. Kawahara, A. Yamaguchi, and T. Nishi. (2011). The sphingosine 1-phosphate transporter, SPNS2, functions as a transporter of the phosphorylated form of the immunomodulating agent FTY720. J. Biol. Chem. 286: 1758-1766.

Hoen, E., F.M. Goossens, K. Falize, S. Mayerl, A.H. van der Spek, and A. Boelen. (2024). The Differential Effect of a Shortage of Thyroid Hormone Compared with Knockout of Thyroid Hormone Transporters Mct8 and Mct10 on Murine Macrophage Polarization. Int J Mol Sci 25:.

Hoischen, C., J. Levin, S. Pitaknarongphorn, J. Reizer, and M.H. Saier, Jr. (1996). Involvement of the central loop of the lactose permease of Escherichia coli in its allosteric regulation by the glucose-specific enzyme IIA of the phosphoenolpyruvate-dependent phosphotransferase system. J. Bacteriol. 178: 6082-6086.

Hollands, K., C.M. Baron, K.J. Gibson, K.J. Kelly, E.A. Krasley, L.A. Laffend, R.M. Lauchli, L.A. Maggio-Hall, M.J. Nelson, J.C. Prasad, Y. Ren, B.A. Rice, G.H. Rice, and S.C. Rothman. (2019). Engineering two species of yeast as cell factories for 2''-fucosyllactose. Metab Eng 52: 232-242.

Holman, G.D. (2020). Structure, function and regulation of mammalian glucose transporters of the SLC2 family. Pflugers Arch. [Epub: Ahead of Print]

Honerlagen, H., H. Reyer, M. Oster, S. Ponsuksili, N. Trakooljul, B. Kuhla, N. Reinsch, and K. Wimmers. (2021). Identification of Genomic Regions Influencing N-Metabolism and N-Excretion in Lactating Holstein- Friesians. Front Genet 12: 699550.

Hopkins AP., Hawkhead JA. and Thomas GH. (2013). Transport and catabolism of the sialic acids N-glycolylneuraminic acid and 3-keto-3-deoxy-D-glycero-D-galactonononic acid by Escherichia coli K-12. FEMS Microbiol Lett. 347(1):14-22.

Horiba, N., S. Masuda, A. Takeuchi, D. Takeuchi, M. Okuda, and K. Inui. (2003). Cloning and characterization of a novel Na+-dependent glucose transporter (NaGLT1) in rat kidney. J. Biol. Chem. 278: 14669-14676.

Horváth, H.R., C.L. Fazekas, D. Balázsfi, S.K. Jain, J. Haller, and D. Zelena. (2018). Contribution of Vesicular Glutamate Transporters to Stress Response and Related Psychopathologies: Studies in VGluT3 Knockout Mice. Cell Mol Neurobiol 38: 37-52.

Hoshino, H. (2012). Cellular Factors Involved in HTLV-1 Entry and Pathogenicit. Front Microbiol 3: 222.

Hosoyamada, M., K. Ichida, A. Enomoto, T. Hosoya, and H. Endou. (2004). Function and localization of urate transporter 1 in mouse kidney. J Am Soc Nephrol 15: 261-268.

Hosoyamada, M., T. Sekine, Y. Kanai, and H. Endou. (1999). Molecular cloning and functional expression of a multispecific organic anion transporter from human kidney. Am. J. Physiol. 276: F122-128.

Hosseini Bereshneh, A. and M. Garshasbi. (2018). Novel in-frame deletion in MFSD8 gene revealed by trio whole exome sequencing in an Iranian affected with neuronal ceroid lipofuscinosis type 7: a case report. J Med Case Rep 12: 281.

Hou, X., Y. Wang, Y. Yang, and Z. Xiao. (2023). Discovery of Novel Biphenyl Carboxylic Acid Derivatives as Potent URAT1 Inhibitors. Molecules 28:.

Hu, B., H.K. Akula, D. Noh, Y.F. Mui, M. Slifstein, R. Parsey, and W. Qu. (2023). An improved synthesis of [ F]VAT and its precursor. J Labelled Comp Radiopharm 66: 384-392.

Hu, C., L. Tao, X. Cao, and L. Chen. (2020). The solute carrier transporters and the brain: Physiological and pharmacological implications. Asian J Pharm Sci 15: 131-144.

Hu, X., X. Peng, Y. Zhang, S. Fan, X. Liu, Y. Song, S. Ren, L. Chen, Y. Chen, R. Wang, J. Peng, X. Shen, and Y. Chen. (2024). Shikonin reverses cancer-associated fibroblast-induced gemcitabine resistance in pancreatic cancer cells by suppressing monocarboxylate transporter 4-mediated reverse Warburg effect. Phytomedicine 123: 155214.

Hu, Y., V. Fernández, and L. Ma. (2014). Nitrate transporters in leaves and their potential roles in foliar uptake of nitrogen dioxide. Front Plant Sci 5: 360.

Hu, Y.W., L. Xiao, L. Zheng, and Q. Wang. (2017). Synaptic vesicle 2C and its synaptic-related function. Clin Chim Acta 472: 112-117.

Huang, B., Z. Lin, Z. Chen, J. Chen, B. Shi, J. Jia, Y. Li, Y. Pan, Y. Liang, and Z. Cai. (2023). Strain differences in the drug transport capacity of intestinal glucose transporters in Sprague-Dawley versus Wistar rats, C57BL/6J versus Kunming mice. Int J Pharm 640: 123000.

Huang, H.T., J.H. Leu, P.Y. Huang, and L.L. Chen. (2012). A putative cell surface receptor for white spot syndrome virus is a member of a transporter superfamily. PLoS One 7: e33216.

Huang, J., P.W. O''Toole, W. Shen, H. Amrine-Madsen, X. Jiang, N. Lobo, L.M. Palmer, L. Voelker, F. Fan, M.N. Gwynn, and D. McDevitt. (2004). Novel chromosomally encoded multidrug efflux transporter MdeA in Staphylococcus aureus. Antimicrob. Agents Chemother. 48: 909-917.

Huang, P., H. Åbacka, D. Varela, R. Venskutonytė, L. Happonen, J.S. Bogan, P. Gourdon, M.R. Amiry-Moghaddam, I. André, and K. Lindkvist-Petersson. (2023). The intracellular helical bundle of human glucose transporter GLUT4 is important for complex formation with ASPL. FEBS Open Bio. [Epub: Ahead of Print]

Huang, X., H. Li, N. Shenkar, and A. Zhan. (2023). Multidimensional plasticity jointly contributes to rapid acclimation to environmental challenges during biological invasions. RNA. [Epub: Ahead of Print]

Huang, Y., M.J. Lemieux, J. Song, M. Auer, and D.N. Wang. (2003). Structure and mechanism of the glycerol-3-phosphate transporter from Escherichia coli. Science 301: 616-620.

Huber, R.J., J. Gray, and W.D. Kim. (2023). Loss of mfsd8 alters the secretome during Dictyostelium aggregation. Eur J. Cell Biol. 102: 151361. [Epub: Ahead of Print]

Huber, R.J., S. Mathavarajah, and S.Q. Yap. (2020). Mfsd8 localizes to endocytic compartments and influences the secretion of Cln5 and cathepsin D in Dictyostelium. Cell Signal 70: 109572.

Hung, H.C., L.C. Li, J.H. Guh, F.L. Kung, and L.C. Hsu. (2022). Discovery of New Glucose Uptake Inhibitors as Potential Anticancer Agents by Non-Radioactive Cell-Based Assays. Molecules 27:.

Huntley, S.A., D. Krofchick, and M. Silverman. (2004). Position 170 of Rabbit Na+/glucose cotransporter (rSGLT1) lies in the Na+ pathway; modulation of polarity/charge at this site regulates charge transfer and carrier turnover. Biophys. J. 87: 295-310.

Hvorup, R.N. and M.H. Saier, Jr. (2002). Sequence similarity between the channel-forming domains of voltage-gated ion channel proteins and the C-terminal domains of secondary carriers of the major facilitator superfamily. Microbiology 148: 3760-3762.

Iannaccone Farkašová, S., P. Vasovčák, D. Sopková, M. Pisarčíková, M. Švajdler, L. Fröhlichová, L. Mistríková, and D. Farkaš. (2019). Neuron.al ceroid lipofuscinosis with cardiac involvement. Cesk Patol 55: 176-181.

Iannelli, F., F. Santoro, M. Santagati, J.D. Docquier, E. Lazzeri, G. Pastore, M. Cassone, M.R. Oggioni, G.M. Rossolini, S. Stefani, and G. Pozzi. (2018). Type M Resistance to Macrolides Is Due to a Two-Gene Efflux Transport System of the ATP-Binding Cassette (ABC) Superfamily. Front Microbiol 9: 1670.

Igarashi, K. and K. Kashiwagi. (2010). Characteristics of cellular polyamine transport in prokaryotes and eukaryotes. Plant Physiol. Biochem 48: 506-512.

Ikeda, M., Y. Mizuno, S. Awane, M. Hayashi, S. Mitsuhashi, and S. Takeno. (2011). Identification and application of a different glucose uptake system that functions as an alternative to the phosphotransferase system in Corynebacterium glutamicum. Appl. Microbiol. Biotechnol. 90: 1443-1451.

Imai, H., K. Yoshimura, Y. Miyamoto, K. Sasa, M. Sugano, M. Chatani, M. Takami, M. Yamamoto, and R. Kamijo. (2019). Roles of monocarboxylate transporter subtypes in promotion and suppression of osteoclast differentiation and survival on bone. Sci Rep 9: 15608.

Inaoka, T., K. Takahashi, M. Ohnishi-Kameyama, M. Yoshida,and K. Ochi. (2003). Guanine nucleotides guanosine 5'-diphosphate 3'-diphosphate and GTP co-operatively regulate the production of an antibiotic bacilysin in Bacillus subtilis. J. Biol. Chem. 278: 2169-2176.

Ingoglia F., Visigalli R., Rotoli BM., Barilli A., Riccardi B., Puccini P. and Dall'Asta V. (2016). Functional activity of L-carnitine transporters in human airway epithelial cells. Biochim Biophys Acta. 1858(2):210-9.

Inoue, K., Y. Nakai, S. Ueda, S. Kamigaso, K.Y. Ohta, M. Hatakeyama, Y. Hayashi, M. Otagiri, and H. Yuasa. (2008). Functional characterization of PCFT/HCP1 as the molecular entity of the carrier-mediated intestinal folate transport system in the rat model. Am. J. Physiol. Gastrointest. Liver Physiol. 294: G660-668.

Iserovich, P., D. Wang, L. Ma, H. Yang, F.A. Zuniga, J.M. Pascual, K. Kuang, D.C. De Vivo, and J. Fischbarg. (2002). Changes in glucose transport and water permeability resulting from the T310I pathogenic mutation in Glut1 are consistent with two transport channels per monomer. J. Biol. Chem. 277: 30991-30997.

Ishida, H., J. Asami, Z. Zhang, T. Nishizawa, H. Shigematsu, U. Ohto, and T. Shimizu. (2021). Cryo-EM structures of Toll-like receptors in complex with UNC93B1. Nat Struct Mol Biol 28: 173-180.

Ismail, A. and M. Tanasova. (2022). Importance of GLUT Transporters in Disease Diagnosis and Treatment. Int J Mol Sci 23:.

Isnardi, I., Y.S. Ng, I. Srdanovic, R. Motaghedi, S. Rudchenko, H. von Bernuth, S.Y. Zhang, A. Puel, E. Jouanguy, C. Picard, B.Z. Garty, Y. Camcioglu, R. Doffinger, D. Kumararatne, G. Davies, J.I. Gallin, S. Haraguchi, N.K. Day, J.L. Casanova, and E. Meffre. (2008). IRAK-4- and MyD88-dependent pathways are essential for the removal of developing autoreactive B cells in humans. Immunity 29: 746-757.

Iwabuchi, T., and S. Harayama. (1997). Biochemical and genetic characterization of 2-carboxybenzaldehyde dehydrogenase, an enzyme involved in phenanthrene degradation by Nocardioides sp. strain KP7. J. Bacteriol. 179: 6488-6494.

Iwai, Y., S. Kamatani, S. Moriyama, and H. Omote. (2019). Function of essential chloride and arginine residue in nucleotide binding to vesicular nucleotide transporter. J Biochem. [Epub: Ahead of Print]

Iwayama, H., T. Tanaka, K. Aoyama, M. Moroto, S. Adachi, Y. Fujisawa, H. Matsuura, K. Takano, H. Mizuno, and A. Okumura. (2021). Regional Difference in Myelination in Monocarboxylate Transporter 8 Deficiency: Case Reports and Literature Review of Cases in Japan. Front Neurol 12: 657820.

Izbicka, E. and R.T. Streeper. (2023). Mitigation of Insulin Resistance by Natural Products from a New Class of Molecules, Membrane-Active Immunomodulators. Pharmaceuticals (Basel) 16:.

Jacobs, C., L. Huang, E. Bartowsky, S. Normark, and J.T. Park. (1994). Bacterial cell wall recycling provides cystolic muropeptides as effectors for β-lactamase induction. EMBO J. 13: 4684-4694.

Janaszkiewicz, A., &.#.1.9.3.;. Tóth, Q. Faucher, H. Arnion, N. Védrenne, C. Barin-Le Guellec, P. Marquet, and F. Di Meo. (2023). Substrate binding and lipid-mediated allostery in the human organic anion transporter 1 at the atomic-scale. Biomed Pharmacother 160: 114342. [Epub: Ahead of Print]

Jansen, J., E.C. Friesema, M.H. Kester, C.E. Schwartz, and T.J. Visser. (2008). Genotype-phenotype relationship in patients with mutations in thyroid hormone transporter MCT8. Endocrinology 149(5): 2184-2190.

Jeanguenin, L., A. Lara-Núñez, D.A. Rodionov, A.L. Osterman, N.Y. Komarova, D. Rentsch, J.F. Gregory, 3rd, and A.D. Hanson. (2012). Comparative genomics and functional analysis of the NiaP family uncover nicotinate transporters from bacteria, plants, and mammals. Funct Integr Genomics 12: 25-34.

Jensen, L.T., M. Ajua-Alemanji, and V. Cizewski Culotta. (2003). The Saccharomyces cerevisiae high affinity phosphate transporter encoded by PHO84 also functions in manganese homeostasis. J. Biol. Chem. 278: 42036-42040.

Jia, B., P. Yuan, W.J. Lan, Y.H. Xuan, and C.O. Jeon. (2019). New insight into the classification and evolution of glucose transporters in the Metazoa. FASEB J. fj201802617R. [Epub: Ahead of Print]

Jia, R., C. Martens, M. Shekhar, S. Pant, G.A. Pellowe, A.M. Lau, H.E. Findlay, N.J. Harris, E. Tajkhorshid, P.J. Booth, and A. Politis. (2020). Hydrogen-deuterium exchange mass spectrometry captures distinct dynamics upon substrate and inhibitor binding to a transporter. Nat Commun 11: 6162.

Jia, W., N. Tovell, S. Clegg, M. Trimmer, and J. Cole. (2009). A single channel for nitrate uptake, nitrite export and nitrite uptake by Escherichia coli NarU and a role for NirC in nitrite export and uptake. Biochem. J. 417: 297-304.

Jiang, D., Y. Zhao, J. Fan, X. Liu, Y. Wu, W. Feng, and X.C. Zhang. (2014). Atomic resolution structure of the E. coli YajR transporter YAM domain. Biochem. Biophys. Res. Commun. 450: 929-935.

Jiang, D., Y. Zhao, X. Wang, J. Fan, J. Heng, X. Liu, W. Feng, X. Kang, B. Huang, J. Liu, and X.C. Zhang. (2013). Structure of the YajR transporter suggests a transport mechanism based on the conserved motif A. Proc. Natl. Acad. Sci. USA 110: 14664-14669.

Jiang, H., J. Chen, X. Du, D. Feng, Y. Zhang, J. Qi, Y. He, Z. An, Y. Lu, C. Ge, and Y. Wang. (2024). Unveiling Synergistic Potency: Exploring Butyrolactone I to Enhance Gentamicin Efficacy against Methicillin-Resistant (MRSA) Strain USA300. ACS Infect Dis 10: 196-214.

Jin, J., A.A. Guffanti, C. Beck, and T.A. Krulwich. (2001). Twelve-transmembrane-segment (TMS) version (*TMS VII-VIII) of the 14-TMS Tel(L) antibiotic resistance protein retains monovalent cation transport modes but lacks tetracycline efflux capacity. J. Bacteriol. 183: 2667-2671.

Jin, J., A.A. Guffanti, D.H. Bechhofer, and T.A. Krulwich. (2002). Tet(L) and Tet(K) tetracycline-divalent metal/H+ antiporters: characterization of multiple catalytic modes and a mutagenesis approach to differences in their efflux substrate and coupling ion preferences. J. Bacteriol. 184: 4722-4732.

Jin, Q., L. Agrawal, Z. VanHorn-Ali, and G. Alkhatib. (2006). Infection of CD4+ T lymphocytes by the human T cell leukemia virus type 1 is mediated by the glucose transporter GLUT-1: evidence using antibodies specific to the receptor''s large extracellular domain. Virology 349: 184-196.

Johannes, J., D. Braun, A. Kinne, D. Rathmann, J. Köhrle, and U. Schweizer. (2016). Few amino acid exchanges expand the substrate spectrum of monocarboxylate transporter 10. Mol Endocrinol me20161037. [Epub: Ahead of Print]

Johannes, J., R. Jayarama-Naidu, F. Meyer, E. Katrin Wirth, U. Schweizer, L. Schomburg, J. Köhrle, and K. Renko. (2016). Silychristin, a flavonolignan derived from the milk thistle is a potent inhibitor of the thyroid hormone transporter MCT8. Endocrinology en20151933. [Epub: Ahead of Print]

Johansen, L.E., P. Nygaard, C. Lassen, Y. Agerso, and H.H. Saxild. (2003). Definition of a second Bacillus subtilis pur regulon comprising the pur and xpt-pbuX operons plus pbuG, nupG (yxjA), and pbuE (ydhL). J. Bacteriol. 185: 5200-5209.

Johansson, L. and G. Lidén. (2006). Transcriptome analysis of a shikimic acid producing strain of Escherichia coli W3110 grown under carbon- and phosphate-limited conditions. J Biotechnol 126: 528-545.

Johnston, M. (1999). Feasting, fasting and fermenting, glucose sensing in yeast and other cells. Trends Genet. 15: 29-33.

Jolfayi, A.G., N. Naderi, S. Ghasemi, A. Salmanipour, S. Adimi, M. Maleki, and S. Kalayinia. (2024). A novel pathogenic variant in the carnitine transporter gene, SLC22A5, in association with metabolic carnitine deficiency and cardiomyopathy features. BMC Cardiovasc Disord 24: 1.

Jones, R.S. and M.E. Morris. (2016). Monocarboxylate Transporters: Therapeutic Targets and Prognostic Factors in Disease. Clin Pharmacol Ther 100: 454-463.

Joost, H.-G. and B. Thorens. (2001). The extended GLUT-family of sugar/polyol transport facilitators: nomenclature, sequence characteristics, and potential function of its novel members. Mol. Membr. Biol. 18: 247-256.

Juge, N., Y. Yoshida, S. Yatsushiro, H. Omote, and Y. Moriyama. (2006). Vesicular glutamate transporter contains two independent transport machineries. J. Biol. Chem. 281: 39499-39506.

Jung, S.K., R. Morimoto, M. Otsuka, and H. Omote. (2006). Transmembrane topology of vesicular glutamate transporter 2. Biol Pharm Bull 29: 547-549.

Jutabha, P., Y. Kanai, M. Hosoyamada, A. Chairoungdua, D.K. Kim, Y. Iribe, E. Babu, J.Y. Kim, N. Anzai, V. Chatsudthipong, and H. Endou. (2003). Identification of a novel voltage-driven organic anion tansporter present at apical membrane of renal proximal tubule. J. Biol. Chem. 278: 27930-27938.

Jørgensen T.R., P.A. vanKuyk, B.R. Poulsen, G.J. Ruijter, J. Visser, J.J. Iversen. (2007). Glucose uptake and growth of glucose-limited chemostat cultures of Aspergillus niger and a disruptant lacking MstA, a high-affinity glucose transporter. Microbiology. 153: 1963-1973.

Kaback, H.R. (2015). A chemiosmotic mechanism of symport. Proc. Natl. Acad. Sci. USA 112: 1259-1264.

Kaback, H.R. and J. Wu. (1997). From membrane to molecule to the third amino acid from the left with a membrane transport protein. Quart. Rev. Biophys. 30: 333-364.

Kalaba, P., K. Pacher, P.J. Neill, V. Dragacevic, M. Zehl, J. Wackerlig, M. Kirchhofer, S.B. Sartori, H. Gstach, S. Kouhnavardi, A. Fabisikova, M. Pillwein, F. Monje-Quiroga, K. Ebner, A. Prado-Roller, N. Singewald, E. Urban, T. Langer, C. Pifl, J. Lubec, J.J. Leban, and G. Lubec. (2023). Chirality Matters: Fine-Tuning of Novel Monoamine Reuptake Inhibitors Selectivity through Manipulation of Stereochemistry. Biomolecules 13:.

Kalashnikova, E., R.A. Lorca, I. Kaur, G.A. Barisone, B. Li, T. Ishimaru, J.S. Trimmer, D.P. Mohapatra, and E. Díaz. (2010). SynDIG1: an activity-regulated, AMPA- receptor-interacting transmembrane protein that regulates excitatory synapse development. Neuron. 65: 80-93.

Kaler, G., D.M. Truong, A. Khandelwal, M. Nagle, S.A. Eraly, P.W. Swaan, and S.K. Nigam. (2007). Structural variation governs substrate specificity for organic anion transporter (OAT) homologs. Potential remote sensing by OAT family members. J. Biol. Chem. 282: 23841-23853.

Kaler, G., D.M. Truong, D.E. Sweeney, D.W. Logan, M. Nagle, W. Wu, S.A. Eraly, and S.K. Nigam. (2006). Olfactory mucosa-expressed organic anion transporter, Oat6, manifests high affinity interactions with odorant organic anions. Biochem. Biophys. Res. Commun. 351: 872-876.

Kanamori, A., J. Nakayama, M.N. Fukuda, W.B. Stallcup, K. Sasaki, M. Fukuda, and Y. Hirabayashi. (1997). Expression cloning and characterization of a cDNA encoding a novel membrane protein required for the formation of O-acetylated ganglioside: a putative acetyl-CoA transporter. Proc. Natl. Acad. Sci. USA 94: 2897-2902.

Kanamori, Y., A. Saito, Y. Hagiwara-Komoda, D. Tanaka, K. Mitsumasu, S. Kikuta, M. Watanabe, R. Cornette, T. Kikawada, and T. Okuda. (2010). The trehalose transporter 1 gene sequence is conserved in insects and encodes proteins with different kinetic properties involved in trehalose import into peripheral tissues. Insect Biochem Mol Biol 40: 30-37.

Kanbay, M., M.C. Bulbul, S. Copur, B. Afsar, A.A. Sag, D. Siriopol, M. Kuwabara, S. Badarau, A. Covic, and A. Ortiz. (2020). Therapeutic implications of shared mechanisms in non-alcoholic fatty liver disease and chronic kidney disease. J Nephrol. [Epub: Ahead of Print]

Karimian, M. and L.N. Ornston. (1981). Participation of the β-ketoadipate transport system in chemotaxis. J Gen Microbiol 124: 25-28.

Kasahara, T. and M. Kasahara. (2010). Identification of a key residue determining substrate affinity in the yeast glucose transporter Hxt7: a two-dimensional comprehensive study. J. Biol. Chem. 285: 26263-26268.

Kasahara, T., K. Shimogawara, and M. Kasahara. (2011). Crucial effects of amino acid side chain length in transmembrane segment 5 on substrate affinity in yeast glucose transporter Hxt7. Biochemistry 50: 8674-8681.

Kasahara, T., M. Maeda, M. Ishiguro, and M. Kasahara. (2007). Identification by comprehensive chimeric analysis of a key residue responsible for high affinity glucose transport by yeast HXT2. J. Biol. Chem. 282: 13146-13150.

Kasho, V.N., I.N. Smirnova, and H.R. Kaback. (2006). Sequence alignment and homology threading reveals prokaryotic and eukaryotic proteins similar to lactose permease. J. Mol. Biol. 358: 1060-1070.

Kathare, P.K., S. Dharmasiri, E.D. Vincill, P. Routray, I. Ahmad, D.M. Roberts, and N. Dharmasiri. (2019). Arabidopsis PIC30 encodes a Major Facilitator Superfamily (MFS) transporter responsible for the uptake of picolinate herbicides. Plant J. [Epub: Ahead of Print]

Kaur, I., V. Yarov-Yarovoy, L.M. Kirk, K.E. Plambeck, E.V. Barragan, E.S. Ontiveros, and E. Díaz. (2016). Activity-Dependent Palmitoylation Controls SynDIG1 Stability, Localization, and Function. J. Neurosci. 36: 7562-7568.

Kaur, J. and A.K. Bachhawat. (2007). Yct1p, a novel, high-affinity, cysteine-specific transporter from the yeast Saccharomyces cerevisiae. Genetics 176: 877-890.

Kawachi, H., G.D. Han, N. Miyauchi, T. Hashimoto, K. Suzuki, and F. Shimizu. (2009). Therapeutic targets in the podocyte: findings in anti-slit diaphragm antibody-induced nephropathy. J Nephrol 22: 450-456.

Kawahara, A., T. Nishi, Y. Hisano, H. Fukui, A. Yamaguchi, and N. Mochizuki. (2009). The sphingolipid transporter spns2 functions in migration of zebrafish myocardial precursors. Science 323: 524-527.

Kawano-Kawada M., Pongcharoen P., Kawahara R., Yasuda M., Yamasaki T., Akiyama K., Sekito T. and Kakinuma Y. (2016). Vba4p, a vacuolar membrane protein, is involved in the drug resistance and vacuolar morphology of Saccharomyces cerevisiae. Biosci Biotechnol Biochem. 80(2):279-87.

Kaya A., Karakaya HC., Fomenko DE., Gladyshev VN. and Koc A. (2009). Identification of a novel system for boron transport: Atr1 is a main boron exporter in yeast. Mol Cell Biol. 29(13):3665-74.

Kayingo, G., A. Martins, R. Andrie, L. Neves, C. Lucas, and B. Wong. (2009). A permease encoded by STL1 is required for active glycerol uptake by Candida albicans. Microbiology 155: 1547-1557.

Kaynar, K., B. Güvercin, M. Şahin, N. Turan, and F. Açíkyürek. (2022). A novel mutation in a patient with familial renal hypouricemia type 2. Nefrologia (Engl Ed) 42: 347-350.

Kazakov, T., A. Metlitskaya, and K. Severinov. (2007). Amino acid residues required for maturation, cell uptake, and processing of translation inhibitor microcin C. J. Bacteriol. 189: 2114-2118.

Keates, R.A., D.E. Culham, Y.I. Vernikovska, A.J. Zuiani, J.M. Boggs, and J.M. Wood. (2010). Transmembrane helix I and periplasmic loop 1 of Escherichia coli ProP are involved in osmosensing and osmoprotectant transport. Biochemistry 49: 8847-8856.

Keel, S.B., R.T. Doty, Z. Yang, J.G. Quigley, J. Chen, S. Knoblaugh, P.D. Kingsley, I. De Domenico, M.B. Vaughn, J. Kaplan, J. Palis, and J.L. Abkowitz (2008). A heme export protein is required for red blood cell differentiation and iron homeostasis. Science 319: 825-828.

Kekuda, R., P.D. Prasad, X. Wu, H. Wang, Y.-J. Fei, F.H. Leibach, and V. Ganapathy. (1998). Cloning and functional characterization of a potential-sensitive polyspecific organic cation transporter (OCT3) most abundantly expressed in placenta. J. Biol. Chem. 273: 15971-15979.

Kemp, B.J., D.L. Church, J. Hatzold, B. Conradt, and E.J. Lambie. (2009). Gem-1 encodes an SLC16 monocarboxylate transporter-related protein that functions in parallel to the gon-2 TRPM channel during gonad development in Caenorhabditis elegans. Genetics 181: 581-591.

Kenny, T.C., A. Khan, Y. Son, L. Yue, S. Heissel, A. Sharma, H.A. Pasolli, Y. Liu, E.R. Gamazon, H. Alwaseem, R.K. Hite, and K. Birsoy. (2023). Integrative genetic analysis identifies FLVCR1 as a plasma-membrane choline transporter in mammals. Cell Metab. [Epub: Ahead of Print]

Khalfaoui-Hassani, B., A.F. Verissimo, H.G. Koch, and F. Daldal. (2016). Uncovering the Transmembrane Metal Binding Site of the Novel Bacterial Major Facilitator Superfamily-Type Copper Importer CcoA. MBio 7:.

Khalfaoui-Hassani, B., P.I. Trasnea, S. Steimle, H.G. Koch, and F. Daldal. (2021). Cysteine Mutants of the Major Facilitator Superfamily-Type Transporter CcoA Provide Insight into Copper Import. mBio e0156721. [Epub: Ahead of Print]

Khan, A., J. Cheng, A. Kitashova, L. Fürtauer, T. Nägele, C. Picco, J. Scholz-Starke, I. Keller, H.E. Neuhaus, and B. Pommerrenig. (2023). Vacuolar sugar transporter EARLY RESPONSE TO DEHYDRATION 6-LIKE4 affects fructose signaling and plant growth. Plant Physiol. [Epub: Ahead of Print]

Khan, A.A. and J.G. Quigley. (2011). Control of intracellular heme levels: heme transporters and heme oxygenases. Biochim. Biophys. Acta. 1813: 668-682.

Khan, A.A. and J.G. Quigley. (2018). Heme and FLVCR-related transporter families SLC48 and SLC49. Mol Aspects Med 34: 669-682.

Khan, A.A., T. Hanada, M. Mohseni, J.J. Jeong, L. Zeng, M. Gaetani, D. Li, B.C. Reed, D.W. Speicher, and A.H. Chishti. (2008). Dematin and adducin provide a novel link between the spectrin cytoskeleton and human erythrocyte membrane by directly interacting with glucose transporter-1. J. Biol. Chem. 283: 14600-14609.

Khare, P., A. Mulakaluri, and S.M. Parsons. (2010). Search for the acetylcholine and vesamicol binding sites in vesicular acetylcholine transporter: the region around the lumenal end of the transport channel. J Neurochem 115: 984-993.

Khlebnikov, A., K.A. Datsenko, T. Skaug, B.L. Wanner, and J.D. Keasling. (2001). Homogeneous expression of the P(BAD) promoter in Escherichia coli by constitutive expression of the low-affinity high-capacity AraE transporter. Microbiology 147: 3241-3247.

Khries, M., A. Lim, D. Mitra, M. Anderson, J. Bengtsson, A. Bowron, E. Harris, J. Blickwedel, K. Wood, and A.P. Basu. (2023). Broadening the Spectrum of Phenotype: Primary Carnitine Deficiency Presenting with Focal Myoclonus. Child Neurol Open 10: 2329048X231184183.

Kikawada, T., A. Saito, Y. Kanamori, Y. Nakahara, K. Iwata, D. Tanaka, M. Watanabe, and T. Okuda. (2007). Trehalose transporter 1, a facilitated and high-capacity trehalose transporter, allows exogenous trehalose uptake into cells. Proc. Natl. Acad. Sci. USA 104: 11585-11590.

Kim JY. and Kandror KV. (2012). The first luminal loop confers insulin responsiveness to glucose transporter 4. Mol Biol Cell. 23(5):910-7.

Kim M.G., F.A. Flomerfelt, K.N. Lee, C. Chen, R.H. Schwartz. (2000). A putative 12 transmembrane domain cotransporter expressed in thymic cortical epithelial cells. J. Immunol. 164:3185-3192.

Kim, D.K., K.H. Kim, E.J. Cho, S.J. Joo, J.M. Chung, B.Y. Son, J.H. Yum, Y.M. Kim, H.J. Kwon, B.W. Kim, T.H. Kim, and E.W. Lee. (2013). Gene cloning and characterization of MdeA, a novel multidrug efflux pump in Streptococcus mutans. J Microbiol Biotechnol 23: 430-435.

Kim, H.J., H. Jeong, and S.J. Lee. (2020). Short-Term Adaptation Modulates Anaerobic Metabolic Flux to Succinate by Activating ExuT, a Novel D-Glucose Transporter in. Front Microbiol 11: 27.

Kim, H.K., I. Lee, H. Bang, H.C. Kim, W.Y. Lee, S.H. Yun, J. Lee, S.J. Lee, Y.S. Park, K.M. Kim, and W.K. Kang. (2018). MCT4 Expression Is a Potential Therapeutic Target in Colorectal Cancer with Peritoneal Carcinomatosis. Mol Cancer Ther 17: 838-848.

Kim, J., S. Park, S. Kim, S. Ryu, H. Hwang, S. Cho, Y. Han, J. Kim, Y. Park, E.K. Lee, and M. Lee. (2024). Enhancing the anticancer effect of androgen deprivation therapy by monocarboxylate transporter 1 inhibitor in prostate cancer cells. Prostate 84: 814-822.

Kim, J.H., L. Mailloux, D. Bloor, B. Maddox, and J. Humble. (2023). The role of salt bridge networks in the stability of the yeast hexose transporter 1. Biochim. Biophys. Acta. Gen Subj 1867: 130490. [Epub: Ahead of Print]

Kim, J.H., L. Mailloux, D. Bloor, H. Tae, H. Nguyen, M. McDowell, J. Padilla, and A. DeWaard. (2024). Multiple roles for the cytoplasmic C-terminal domains of the yeast cell surface receptors Rgt2 and Snf3 in glucose sensing and signaling. Sci Rep 14: 4055.

Kim, O.B., H. Richter, T. Zaunmüller, S. Graf, and G. Unden. (2011). Role of secondary transporters and phosphotransferase systems in glucose transport by Oenococcus oeni. J. Bacteriol. 193: 6902-6911.

Kim, T.W., D.H. Pyo, E. Ko, N.H. Yun, S.J. Song, S.M. Choi, H.K. Hong, S.H. Kim, Y.L. Choi, J. Lee, W.Y. Lee, and Y.B. Cho. (2022). Expression of SLC22A18 regulates oxaliplatin resistance by modulating the ERK pathway in colorectal cancer. Am J Cancer Res 12: 1393-1408.

Kimura, Y., S. Ishida, H. Matoba, and N. Okahisa. (2004). A Myxococcus xanthus rppA-mmrA double mutant exhibits reduced uptake of amino acids and tolerance of some antimicrobials. FEMS Microbiol. Lett. 238: 145-150.

King, S.C. and T.H. Wilson. (1990). Identification of valine 177 as a mutation altering specificity for transport of sugars by the Escherichia coli lactose carrier. Enhanced specificity for sucrose and maltose. J. Biol. Chem. 265: 9638-9644.

Kinne, A., G. Kleinau, C.S. Hoefig, A. Grüters, J. Köhrle, G. Krause, and U. Schweizer. (2010). Essential molecular determinants for thyroid hormone transport and first structural implications for monocarboxylate transporter 8. J. Biol. Chem. 285: 28054-28063.

Kinne, A., R. Schülein, and G. Krause. (2011). Primary and secondary thyroid hormone transporters. Thyroid Res 4Suppl1: S7.

Kitagawa, W., S. Takami, K. Miyauchi, E. Masai, Y. Kamagata, J.M. Tiedje, and M. Fukuda. (2002). Novel 2,4-dichlorophenoxyacetic acid degradation genes from oligotrophic Bradyrhizobium sp. strain HW13 isolated from a pristine environment. J. Bacteriol. 184: 509-518.

Kitamura, Y., M. Kandeel, E. Oba, C. Iwai, K. Iritani, N. Nagaya, R. Namura, H. Katagiri, H. Ueda, and Y. Kitade. (2023). A Diversifiable Synthetic Platform for the Discovery of New Carbasugar SGLT2 Inhibitors Using Azide-Alkyne Click Chemistry. Chem Pharm Bull (Tokyo) 71: 240-249.

Klepek, Y.S., D. Geiger, R. Stadler, F. Klebl, L. Landouar-Arsivaud, R. Lemoine, R. Hedrich, and N. Sauer. (2005). Arabidopsis POLYOL TRANSPORTER5, a new member of the monosaccharide transporter-like superfamily, mediates H+-Symport of numerous substrates, including myo-inositol, glycerol, and ribose. Plant Cell 17: 204-218.

Kodippili, G.C., K. Giger, K.S. Putt, and P.S. Low. (2020). DARC, Glycophorin A, Band 3, and GLUT1 Diffusion in Erythrocytes: Insights into Membrane Complexes. Biophys. J. 119: 1749-1759.

Koepsell, H. (1998). Organic cation transporters in intestine, kidney, liver, and brain. Annu. Rev. Physiol. 60: 243-266.

Koepsell, H. (2013). The SLC22 family with transporters of organic cations, anions and zwitterions. Mol Aspects Med 34: 413-435.

Koepsell, H., V. Gorboulev, and P. Arndt. (1999). Molecular pharmacology of organic cation transporters in kidney. J. Membr. Biol. 167: 103-117.

Kohyama, N., H. Shiokawa, M. Ohbayashi, Y. Kobayashi, and T. Yamamoto. (2013). Characterization of monocarboxylate transporter 6: expression in human intestine and transport of the antidiabetic drug nateglinide. Drug Metab Dispos 41: 1883-1887.

Koita, K. and C.V. Rao. (2012). Identification and analysis of the putative pentose sugar efflux transporters in Escherichia coli. PLoS One 7: e43700.

Koleske, M.L., G. McInnes, J.E.H. Brown, N. Thomas, K. Hutchinson, M.Y. Chin, A. Koehl, M.R. Arkin, A. Schlessinger, R.C. Gallagher, Y.S. Song, R.B. Altman, and K.M. Giacomini. (2022). Functional genomics of OCTN2 variants informs protein-specific variant effect predictor for Carnitine Transporter Deficiency. Proc. Natl. Acad. Sci. USA 119: e2210247119.

Kong, K.F., A. Aguila, L. Schneper, and K. Mathee. (2010). Pseudomonas aeruginosa β-lactamase induction requires two permeases, AmpG and AmpP. BMC Microbiol 10: 328.

Kramer, W., H.J. Burger, W.J. Arion, D. Corsiero, F. Girbig, C. Weyland, H. Hemmerle, S. Petry, P. Habermann, and A. Herling. (1999). Identification of protein components of the microsomal glucose 6-phosphate transporter by photoaffinity labelling. J. Biochem. 339: 629-638.

Krause, G. and K.M. Hinz. (2019). Molecular Mechanisms of Thyroid Hormone Transport by l-Type Amino Acid Transporter. Exp Clin Endocrinol Diabetes. [Epub: Ahead of Print]

Kravtsova, O., V. Levchenko, C.A. Klemens, T. Rieg, R. Liu, and A. Staruschenko. (2023). Effect of SGLT2 inhibition on salt-induced hypertension in female Dahl SS rats. Sci Rep 13: 19231.

Krings, E., K. Krumbach, B. Bathe, R. Kelle, V.F. Wendisch, H. Sahm, and L. Eggeling. (2006). Characterization of myo-inositol utilization by Corynebacterium glutamicum: the stimulon, identification of transporters, and influence on L-lysine formation. J. Bacteriol. 188: 8054-8061.

Kristoficova, I., C. Vilhena, S. Behr, and K. Jung. (2017). BtsT - a novel and specific pyruvate/H+ symporter in Escherichia coli. J. Bacteriol. [Epub: Ahead of Print]

Kroeger, J.K., K. Hassan, A. Vörös, R. Simm, M. Saidijam, K.E. Bettaney, A. Bechthold, I.T. Paulsen, P.J. Henderson, and A.B. Kolstø. (2015). Bacillus cereus efflux protein BC3310 - a multidrug transporter of the unknown major facilitator family, UMF-2. Front Microbiol 6: 1063.

Kröger, C., J. Stolz, and T.M. Fuchs. (2010). myo-Inositol transport by Salmonella enterica serovar Typhimurium. Microbiology 156: 128-138.

Kuehne, A., S. Floerl, and Y. Hagos. (2022). Investigations with Drugs and Pesticides Revealed New Species- and Substrate-Dependent Inhibition by Elacridar and Imazalil in and Organic Cation Transporter OCT2. Int J Mol Sci 23:.

Kulakova, A.N., L.A. Kulakov, N.V. Akulenko, V.N. Ksenzenko, J.T. Hamilton, and J.P. Quinn. (2001). Structural and functional analysis of the phosphonoacetate hydrolase (phnA) gene region in Pseudomonas fluorescens 23F. J. Bacteriol. 183: 3268-3275.

Kumar, A., N. Sandhu, P. Kumar, G. Pruthi, J. Singh, S. Kaur, and P. Chhuneja. (2022). Genome-wide identification and in silico analysis of NPF, NRT2, CLC and SLAC1/SLAH nitrate transporters in hexaploid wheat (Triticum aestivum). Sci Rep 12: 11227.

Kumar, H., J.S. Finer-Moore, X. Jiang, I. Smirnova, V. Kasho, E. Pardon, J. Steyaert, H.R. Kaback, and R.M. Stroud. (2018). Crystal Structure of a ligand-bound LacY-Nanobody Complex. Proc. Natl. Acad. Sci. USA 115: 8769-8774.

Kumar, H., V. Kasho, I. Smirnova, J.S. Finer-Moore, H.R. Kaback, and R.M. Stroud. (2014). Structure of sugar-bound LacY. Proc. Natl. Acad. Sci. USA 111: 1784-1788.

Kumar, S., A. Athreya, A. Gulati, R.M. Nair, I. Mahendran, R. Ranjan, and A. Penmatsa. (2021). Structural basis of inhibition of a transporter from Staphylococcus aureus, NorC, through a single-domain camelid antibody. Commun Biol 4: 836.

Kusuhara, H., T. Sekine, N. Utsunomiya-Tate, M. Tsuda, R. Kojima, S.H. Cha, Y. Sugiyama, Y. Kanai, and H. Endou. (1999). Molecular cloning and characterization of a new multispecific organic anion transporter from rat brain. J. Biol. Chem. 274: 13675-13680.

Lages, M.A., L. Ageitos, J. Rodríguez, C. Jiménez, M.L. Lemos, and M. Balado. (2022). Identification of Key Functions Required for Production and Utilization of the Siderophore Piscibactin Encoded by the High-Pathogenicity Island -HPI in. Int J Mol Sci 23:.

Lan, Q., Z. Zhao, H. Liao, F. Zheng, Y. Chen, T. Wu, Y. Tian, and J. Pang. (2022). Mutation in Transmembrane Domain 8 of Human Urate Transporter 1 Disrupts Uric Acid Recognition and Transport. ACS Omega 7: 34621-34631.

Langford, C.K., M.P. Kavanaugh, P.E. Stenberg, M.E. Drew, W. Zhang, and S.M. Landfear. (1995). Functional expression and subcellular localization of a high-Kmhexose transporter from Leishmania donovani. Biochemistry 34: 11814-11821.

Latunde-Dada, G.O., R.J. Simpson, and A.T. McKie. (2006). Recent advances in mammalian haem transport. Trends Biochem. Sci. 31: 182-188.

Laurent M., B. Aude and R. Cornelia. (2007). Ferripyochelin uptake genes are involved in pyochelin-mediated signaling in Pseudomonas aeruginosa. Microbiology 153: 1508-1518.

Law, C.J., P.C. Maloney, and D.N. Wang. (2008). Ins and outs of major facilitator superfamily antiporters. Annu. Rev. Microbiol. 62: 289-305.

Law, C.J., Q. Yang, C. Soudant, P.C. Maloney, and D.N. Wang. (2007). Kinetic evidence is consistent with the rocker-switch mechanism of membrane transport by GlpT. Biochemistry. 46: 12190-12197.

Lawal, H.O. and D.E. Krantz. (2018). SLC18: Vesicular neurotransmitter transporters for monoamines and acetylcholine. Mol Aspects Med 34: 360-372.

Lazard, M., S. Blanquet, P. Fisicaro, G. Labarraque, and P. Plateau. (2010). Uptake of selenite by Saccharomyces cerevisiae involves the high and low affinity orthophosphate transporters. J. Biol. Chem. 285: 32029-32037.

Leach, L.H. and T.A. Lewis. (2006). Identification and characterization of Pseudomonas membrane transporters necessary for utilization of the siderophore pyridine-2,6-bis(thiocarboxylic acid) (PDTC). Microbiology 152: 3157-3166.

Leal-Cardoso, J.H., F.W. Ferreira-da-Silva, A.N. Coelho-de-Souza, and K.S. da Silva-Alves. (2023). Diabetes-induced electrophysiological alterations on neurosomes in ganglia of peripheral nervous system. Biophys Rev 15: 625-638.

Leandro, M.J., H. Sychrová, C. Prista, and M.C. Loureiro-Dias. (2011). The osmotolerant fructophilic yeast Zygosaccharomyces rouxii employs two plasma-membrane fructose uptake systems belonging to a new family of yeast sugar transporters. Microbiology 157: 601-608.

Leandro, M.J., I. Spencer-Martins, and P. Gonçalves. (2008). The expression in Saccharomyces cerevisiae of a glucose/xylose symporter from Candida intermedia is affected by the presence of a glucose/xylose facilitator. Microbiology 154: 1646-1655.

Leandro, M.J., P. Gonçalves, and I. Spencer-Martins. (2006). Two glucose/xylose transporter genes from the yeast Candida intermedia: first molecular characterization of a yeast xylose-H+ symporter. Biochem. J. 395: 543-549.

Lechermeier, C.G., F. Zimmer, T.M. Lüffe, K.P. Lesch, M. Romanos, C. Lillesaar, and C. Drepper. (2019). Transcript Analysis of Zebrafish GLUT3 Genes, and , Define Overlapping as Well as Distinct Expression Domains in the Zebrafish () Central Nervous System. Front Mol Neurosci 12: 199.

Lee, E.-H., C. Rouquette-Loughlin, J.P. Folster, and W.M. Shafer. (2003). FarR regulates the farAB-encoded efflux pump of Neisseria gonorrhoeae via an MtrR regulatory mechanism. J. Bacteriol. 185: 7145-7152.

Lee, E.E., J. Ma, A. Sacharidou, W. Mi, V.K. Salato, N. Nguyen, Y. Jiang, J.M. Pascual, P.E. North, P.W. Shaul, M. Mettlen, and R.C. Wang. (2015). A Protein Kinase C Phosphorylation Motif in GLUT1 Affects Glucose Transport and is Mutated in GLUT1 Deficiency Syndrome. Mol. Cell 58: 845-853.

Lee, E.H., S.A. Hill, R. Napier, and W.M. Shafer. (2006). Integration Host Factor is required for FarR repression of the farAB-encoded efflux pump of Neisseria gonorrhoeae. Mol Microbiol. 60: 1381-1400.

Lee, H., H.J. Kim, D.K. Choi, E.N. Ko, J.H. Choi, Y. Seo, S. Lee, S.H. Kim, S. Jung, M. Kim, D. Kang, C.Y. Im, G.H. Bae, S.C. Jung, and O.B. Kwon. (2023). Dopaminergic cell protection and alleviation of neuropsychiatric disease symptoms by VMAT2 expression through the class I HDAC inhibitor TC-H 106. Pharmacol Res Perspect 11: e01135.

Lee, L.F., Y.J. Chen, R. Kirby, C. Chen, and C.W. Chen. (2007). A multidrug efflux system is involved in colony growth in Streptomyces lividans. Microbiology. 153: 924-934.

Lee, T., Y.K. Han, K.H. Kim, S.H. Yun, and Y.W. Lee. (2002). Tri13 and Tri7 determine deoxynivalenol- and nivalenol-producing chemotypes of Gibberella zeae. Appl. Environ. Microbiol. 68: 2148-2154.

Leeb, T., F. Leuthard, V. Jagannathan, S. Kiener, A. Letko, P. Roosje, M.M. Welle, K.L. Gailbreath, A. Cannon, M. Linek, F. Banovic, T. Olivry, S.D. White, K. Batcher, D. Bannasch, K.M. Minor, J.R. Mickelson, M.K. Hytönen, H. Lohi, E.A. Mauldin, and M.L. Casal. (2020). A Missense Variant Affecting the C-Terminal Tail of UNC93B1 in Dogs with Exfoliative Cutaneous Lupus Erythematosus (ECLE). Genes (Basel) 11:.

Lehman, M.K., N.A. Sturd, F. Razvi, D.L. Wellems, S.D. Carson, and P.D. Fey. (2023). Proline transporters ProT and PutP are required for Staphylococcus aureus infection. PLoS Pathog 19: e1011098.

Lei, M., Q. Cheng, Y. Zhao, T. Liu, X. Wang, Y. Deng, J. Yang, and Z. Zhang. (2012). [Expression and Its Clinical Significance of SLC22A18 in Non-small Cell Lung Cancer]. Zhongguo Fei Ai Za Zhi 15: 17-20.

Lekholm, E., E. Perland, M.M. Eriksson, S.V. Hellsten, F.A. Lindberg, J. Rostami, and R. Fredriksson. (2017). Putative Membrane-Bound Transporters MFSD14A and MFSD14B Are Neuron.al and Affected by Nutrient Availability. Front Mol Neurosci 10: 11.

Lelandais-Brière, C., M. Jovanovic, G.A. Torres, Y. Perrin, R. Lemoine, F. Corre-Menguy, and C. Hartmann. (2007). Disruption of AtOCT1, an organic cation transporter gene, affects root development and carnitine-related responses in Arabidopsis. Plant J. 51: 154-164.

Lemieux, M.J. (2007). Eukaryotic major facilitator superfamily transporter modeling based on the prokaryotic GlpT crystal structure. Mol. Membr. Biol. 24: 333-341.

Lemieux, M.J., Y. Huang, and d.a.N. Wang. (2005). Crystal structure and mechanism of GlpT, the glycerol-3-phosphate transporter from E. coli. J Electron Microsc (Tokyo) 54Suppl1: i43-46.

Lesuisse, E., M. Simon-Casteras, and P. Labbe. (1998). Siderophore-mediated iron uptake in Saccharomyces cerevisiae: the SIT1 gene encodes a ferrioxamine B permease that belongs to the major facilitator superfamily. Microbiology 144: 3455-3462.

Lewinson O., J. Adler, N. Sigal, E. Bibi. (2006). Promiscuity in multidrug recognition and transport: the bacterial MFS Mdr transporters. Mol. Microbiol. 61: 277-284.

Lewinson, O., and E. Bibi. (2001). Evidence for simultaneous binding of dissimilar substrates by the Escherichia coli multidrug transporter MdfA. Biochem. 40: 12612-12618.

Lewis, J.A., A.R. Horswill, B.E. Schwem, and J.C. Escalante-Semerena. (2004). The tricarballylate utilization (tcuRABC) genes of Salmonella enterica serovar Typhimurium LT2. J. Bacteriol. 186: 1629-1637.

Leyn, S.A., F. Gao, C. Yang, and D.A. Rodionov. (2012). N-acetylgalactosamine utilization pathway and regulon in proteobacteria: genomic reconstruction and experimental characterization in Shewanella. J. Biol. Chem. 287: 28047-28056.

Li H., Fan R., Li L., Wei B., Li G., Gu L., Wang X. and Zhang X. (2014). Identification and characterization of a novel copper transporter gene family TaCT1 in common wheat. Plant Cell Environ. 37(7):1561-73.

Li, D., Y. Ge, N. Wang, Y. Shi, G. Guo, Q. Zou, and Q. Liu. (2023). Identification and Characterization of a Novel Major Facilitator Superfamily Efflux Pump, SA09310, Mediating Tetracycline Resistance in Staphylococcus aureus. Antimicrob. Agents Chemother. e0169622. [Epub: Ahead of Print]

Li, F., J. Eriksen, J. Finer-Moore, R. Chang, P. Nguyen, A. Bowen, A. Myasnikov, Z. Yu, D. Bulkley, Y. Cheng, R.H. Edwards, and R.M. Stroud. (2020). Ion transport and regulation in a synaptic vesicle glutamate transporter. Science 368: 893-897.

Li, F., J. Eriksen, J. Finer-Moore, R.M. Stroud, and R.H. Edwards. (2022). Diversity of function and mechanism in a family of organic anion transporters. Curr. Opin. Struct. Biol. 75: 102399.

Li, H., C. Yang, J. Zhang, W. Zhong, L. Zhu, and Y. Chen. (2020). Identification of potential key mRNAs and LncRNAs for psoriasis by bioinformatic analysis using weighted gene co-expression network analysis. Mol. Genet. Genomics 295: 741-749.

Li, P., J. Ying, G. Yang, A. Li, J. Wang, J. Lu, J. Wang, T. Xu, H. Yi, K. Li, S. Jin, Q. Bao, and K. Zhang. (2016). Structure-Function Analysis of the Transmembrane Protein AmpG from Pseudomonas aeruginosa. PLoS One 11: e0168060.

Li, Q., X. Qin, X. Kou, J. Li, Z. Li, and C. Chen. (2022). Anagliptin promotes apoptosis in mouse colon carcinoma cells via MCT-4/lactate-mediated intracellular acidosis. Exp Ther Med 23: 282.

Li, R., R. Kumar, S. Tati, S. Puri, and M. Edgerton. (2013). Candida albicans flu1-mediated efflux of salivary histatin 5 reduces its cytosolic concentration and fungicidal activity. Antimicrob. Agents Chemother. 57: 1832-1839.

Li, S., J. Liu, Z. Li, L. Wang, W. Gao, Z. Zhang, and C. Guo. (2020). Sodium-dependent glucose transporter 1 and glucose transporter 2 mediate intestinal transport of quercetrin in Caco-2 cells. Food Nutr Res 64:.

Li, X., C. Brunner, Y. Wu, O. Leka, G. Schneider, and R.A. Kammerer. (2020). Structural insights into the interaction of botulinum neurotoxin a with its neuronal receptor SV2C. Toxicon 175: 36-43.

Li, X., H. Yang, D. Zhang, X. Li, H. Yu, and Z. Shen. (2015). Overexpression of specific proton motive force-dependent transporters facilitate the export of surfactin in Bacillus subtilis. J Ind Microbiol Biotechnol 42: 93-103.

Li, X., W. Wang, J. Yan, and F. Zeng. (2021). Glutamic Acid Transporters: Targets for Neuroprotective Therapies in Parkinson''s Disease. Front Neurosci 15: 678154.

Li, X., Y. Yang, C. Zhan, Z. Zhang, X. Liu, H. Liu, and Z. Bai. (2017). Transcriptional analysis of impacts of glycerol transporter 1 on methanol and glycerol metabolism in Pichia pastoris. FEMS Yeast Res. [Epub: Ahead of Print]

Li, X.T., L.C. Thomason, J.A. Sawitzke, N. Costantino, and D.L. Court. (2013). Positive and negative selection using the tetA-sacB cassette: recombineering and P1 transduction in Escherichia coli. Nucleic Acids Res 41: e204.

Li, X.Z., L. Zhang, and H. Nikaido. (2004). Efflux pump-mediated intrinsic drug resistance in Mycobacterium smegmatis. Antimicrob. Agents Chemother. 48: 2415-2423.

Li, Y., Y. Ge, M. Zhao, F. Ding, X. Wang, Z. Shi, X. Ge, X. Wang, and X. Qian. (2023). HSP90B1-mediated plasma membrane localization of GLUT1 promotes radioresistance of glioblastomas. J Biomed Res 326-339. [Epub: Ahead of Print]

Li, Z. (2019). Further insights into cardiovascular outcomes in diabetic and non-diabetic states: inhibition of sodium-glucose co-transports. Cardiovasc Endocrinol Metab 8: 90-95.

Li, Z., Q. Wu, S. Sun, J. Wu, J. Li, Y. Zhang, C. Wang, J. Yuan, and S. Sun. (2018). Monocarboxylate transporters in breast cancer and adipose tissue are novel biomarkers and potential therapeutic targets. Biochem. Biophys. Res. Commun. 501: 962-967.

Lian, J., Y. Li, M. HamediRad, and H. Zhao. (2014). Directed evolution of a cellodextrin transporter for improved biofuel production under anaerobic conditions in Saccharomyces cerevisiae. Biotechnol Bioeng 111: 1521-1531.

Liang, H., A. Mokrani, H. Chisomo-Kasiya, O.M. Wilson-Arop, H. Mi, K. Ji, X. Ge, and M. Ren. (2018). Molecular characterization and identification of facilitative glucose transporter 2 (GLUT2) and its expression and of the related glycometabolism enzymes in response to different starch levels in blunt snout bream (Megalobrama amblycephala). Fish Physiol Biochem. [Epub: Ahead of Print]

Liang, H., S. Maulu, K. Ji, X. Ge, M. Ren, and H. Mi. (2020). Functional Characterization of Facilitative Glucose Transporter 4 With a Delay Responding to Plasma Glucose Level in Blunt Snout Bream (). Front Physiol 11: 582785.

Liang, X., F. Yan, Y. Gao, M. Xiong, H. Wang, K. Onxayvieng, R. Tang, L. Li, X. Zhang, W. Chi, M. Piria, M.M. Fuka, A. Gavrilović, and D. Li. (2020). Sugar transporter genes in grass carp (Ctenopharyngodon idellus): molecular cloning, characterization, and expression in response to different stocking densities. Fish Physiol Biochem. [Epub: Ahead of Print]

Lin, H.C., P.L. Yu, L.H. Chen, H.C. Tsai, and K.R. Chung. (2018). A Major Facilitator Superfamily Transporter Regulated by the Stress-Responsive Transcription Factor Yap1 Is Required for Resistance to Fungicides, Xenobiotics, and Oxidants and Full Virulence in. Front Microbiol 9: 2229.

Lin, M.W., C.I. Chen, T.T. Cheng, C.C. Huang, J.W. Tsai, G.M. Feng, T.Z. Hwang, and C.F. Lam. (2021). Prolonged preoperative fasting induces postoperative insulin resistance by ER-stress mediated Glut4 down-regulation in skeletal muscles. Int J Med Sci 18: 1189-1197.

Lin, Y., M. Bogdanov, S. Tong, Z. Guan, and L. Zheng. (2016). Substrate Selectivity of Lysophospholipid Transporter LplT Involved in Membrane Phospholipid Remodeling in Escherichia coli. J. Biol. Chem. 291: 2136-2149.

Lin, Y., R.N.V.K. Deepak, J.Z. Zheng, H. Fan, and L. Zheng. (2018). A dual substrate-accessing mechanism of a major facilitator superfamily protein facilitates lysophospholipid flipping across the cell membrane. J. Biol. Chem. [Epub: Ahead of Print]

Lindquist, S., K. Weston-Hafer, H. Schmidt, C. Pul, G. Korfmann, J. Erickson, C. Sanders, H.H. Martin, and S. Normark. (1993). AmpG, a single transducer in chromosomal β-lactamase induction. Mol. Microbiol. 9: 703-715.

Liu, B., S. Zhao, X. Wu, X. Wang, Y. Nan, D. Wang, and Q. Chen. (2017). Identification and characterization of phosphate transporter genes in potato. J Biotechnol 264: 17-28.

Liu, C., J. Su, G.K. Stephen, H. Wang, A. Song, F. Chen, Y. Zhu, S. Chen, and J. Jiang. (2018). Overexpression of Phosphate Transporter Gene Facilitated Pi Uptake and Alternated the Metabolic Profiles of Chrysanthemum Under Phosphate Deficiency. Front Plant Sci 9: 686.

Liu, H., Y. Wang, C. Wu, S. Schwarz, Z. Shen, B. Jeon, S. Ding, Q. Zhang, and J. Shen. (2012). A novel phenicol exporter gene, fexB, found in enterococci of animal origin. J Antimicrob Chemother 67: 322-325.

Liu, J., L. Yang, M. Luan, Y. Wang, C. Zhang, B. Zhang, J. Shi, F.G. Zhao, W. Lan, and S. Luan. (2015). A vacuolar phosphate transporter essential for phosphate homeostasis in Arabidopsis. Proc. Natl. Acad. Sci. USA 112: E6571-6578.

Liu, J., W.K. Versaw, N. Pumplin, S.K. Gomez, L.A. Blaylock, and M.J. Harrison. (2008). Closely related members of the Medicago truncatula PHT1 phosphate transporter gene family encode phosphate transporters with distinct biochemical activities. J. Biol. Chem. 283: 24673-24681.

Liu, J.Y., P.F. Miller, J. Willard, and E.R. Olson. (1999). Functional and biochemical characterization of Escherichia coli sugar efflux transporters. J. Biol. Chem. 274: 22977-22984.

Liu, J.Y., P.F. Miller, M. Gosink, and E.R. Olson. (1999). The identification of a new family of sugar efflux pumps in Escherichia coli. Mol. Microbiol. 31: 1845-1851.

Liu, K.-H. and Y.-F. Tsay. (2003). Switching between the two action modes of the dual-affinity nitrate transporter CHL1 by phosphorylation. EMBO J. 22: 1005-1013.

Liu, M., J. Liu, and W.M. Wang. (2012). Isolation and functional analysis of Thmfs1, the first major facilitator superfamily transporter from the biocontrol fungus Trichoderma harzianum. Biotechnol Lett 34: 1857-1862.

Liu, N., Q. Wang, C. He, and B. An. (2021). CgMFS1, a Major Facilitator Superfamily Transporter, Is Required for Sugar Transport, Oxidative Stress Resistance, and Pathogenicity of from. Curr Issues Mol Biol 43: 1548-1557.

Liu, Q., H. Dang, Z. Chen, J. Wu, Y. Chen, S. Chen, and L. Luo. (2018). Genome-Wide Identification, Expression, and Functional Analysis of the Sugar Transporter Gene Family in Cassava (Manihot esculenta). Int J Mol Sci 19:.

Liu, Y., D. Peter, A. Roghani, S. Schuldiner, G.G. Prive, D. Eisenberg, N. Brecha, and R.H. Edwards. (1992). A cDNA that suppresses MPP+ toxicity encodes a vesicular amine transporter. Cell 70: 539-551.

Liu, Y., F. Liu, K. Iqbal, I. Grundke-Iqbal, and C.X. Gong. (2008). Decreased glucose transporters correlate to abnormal hyperphosphorylation of tau in Alzheimer disease. FEBS Lett. 582: 359-364.

Liu, Y., P. Dodds, G. Emilion, A.J. Mungall, I. Dunham, S. Beck, R.S. Wells, F.M. Charnock, and T.S. Ganesan. (2002). The human homologue of unc-93 maps to chromosome 6q27 - characterisation and analysis in sporadic epithelial ovarian cancer. BMC Genet 3: 20.

Liu, Z., E. Boles, and B.P. Rosen. (2004). Arsenic trioxide uptake by hexose permeases in Saccharomyces cerevisiae. J. Biol. Chem. 279: 17312-17318.

Lo, C.H. and J. Zeng. (2023). Defective lysosomal acidification: a new prognostic marker and therapeutic target for neurodegenerative diseases. Transl Neurodegener 12: 29.

Locher, K.P., R.B. Bass, and D.C. Rees. (2003). Breaching the barrier. Science 301: 603-604.

Lodder-Gadaczek, J., V. Gieselmann, and M. Eckhardt. (2013). Vesicular uptake of N-acetylaspartylglutamate is catalysed by sialin (SLC17A5). Biochem. J. 454: 31-38.

Lofthouse EM., Brooks S., Cleal JK., Hanson MA., Poore KR., O'Kelly IM. and Lewis RM. (2015). Glutamate cycling may drive organic anion transport on the basal membrane of human placental syncytiotrophoblast. J Physiol. 593(20):4549-59.

Loland, C.J., P. Wellendorph, S.F. Pedersen, and U. Gether. (2023). Transmembrane transporter proteins: Capturing transport in motion. Basic Clin Pharmacol Toxicol. [Epub: Ahead of Print]

Long, W., R. Panigrahi, P. Panwar, K. Wong, D. O Neill, X.Z. Chen, M.J. Lemieux, and C.I. Cheeseman. (2017). Identification of Key Residues for Urate Specific Transport in Human Glucose Transporter 9 (hSLC2A9). Sci Rep 7: 41167.

López, D.M., L. Kählau, K.E.J. Jungnickel, C. Löw, and M. Damme. (2020). Characterization of the complex of the lysosomal membrane transporter MFSD1 and its accessory subunit GLMP. FASEB J. [Epub: Ahead of Print]

López-Errasquín, E., M.T. González-Jaén, C. Callejas, and C. Vázquez. (2006). A novel MFS transporter encoding gene in Fusarium verticillioides probably involved in iron-siderophore transport. Mycol Res 110: 1102-1110.

López-Igual, R., S. Lechno-Yossef, Q. Fan, A. Herrero, E. Flores, and C.P. Wolk. (2012). A major facilitator superfamily protein, HepP, is involved in formation of the heterocyst envelope polysaccharide in the cyanobacterium Anabaena sp. strain PCC 7120. J. Bacteriol. 194: 4677-4687.

Lorca, G.L., R.D. Barabote, V. Zlotopolski, C. Tran, B. Winnen, R.N. Hvorup, A.J. Stonestrom, E. Nguyen, L.W. Huang, D.S. Kim, and M.H. Saier, Jr. (2007). Transport capabilities of eleven gram-positive bacteria: comparative genomic analyses. Biochim. Biophys. Acta. 1768: 1342-1366.

Löscher, W., M. Gillard, Z.A. Sands, R.M. Kaminski, and H. Klitgaard. (2016). Synaptic Vesicle Glycoprotein 2A Ligands in the Treatment of Epilepsy and Beyond. CNS Drugs 30: 1055-1077.

Löw, C., K. Bartels, T. Lasitza-Male, and H. Hofmann. (2021). Single-Molecule FRET of Membrane Transport Proteins. Chembiochem. [Epub: Ahead of Print]

Lubitz, D., J.M. Jorge, F. Pérez-García, H. Taniguchi, and V.F. Wendisch. (2016). Roles of export genes cgmA and lysE for the production of L-arginine and L-citrulline by Corynebacterium glutamicum. Appl. Microbiol. Biotechnol. 100: 8465-8474.

Luo, Y., Z. Akhatayeva, C. Mao, F. Jiang, Z. Guo, H. Xu, and X. Lan. (2023). The ovine gene: mRNA expression, InDel mutations, and growth trait associations. Front Vet Sci 10: 1134903.

Ma, Y., J. Patel, and R.J. Parry. (2000). A novel valanimycin-resistance determinant (vlmF) from Streptomyces viridifaciens MG456-hF10. Microbiology 146(Pt2): 345-352.

Ma, Y., X. Chen, T. Diao, Y. Leng, X. Lai, and X. Wei. (2022). The Effect of Ferulic Acid-Grafted Chitosan (FA-g-CS) on the Transmembrane Transport of Anthocyanins by and. Foods 11:.

MacMillan, S.V., D.A. Alexander, D.E. Culham, H.J. Kunte, E.V. Marshall, D. Rochon, and J.M. Wood. (1999). The ion coupling and organic substrate specificities of osmoregulatory transporter ProP in Escherichia coli. Biochim. Biophys. Acta 1420: 30-44.

Madej, M.G., S.N. Soro, and H.R. Kaback. (2012). Apo-intermediate in the transport cycle of lactose permease (LacY). Proc. Natl. Acad. Sci. USA 109: E2970-2978.

Magalhães, F., V. Vidgren, L. Ruohonen, and B. Gibson. (2016). Maltose and maltotriose utilisation by group I strains of the hybrid lager yeast Saccharomyces pastorianus. FEMS Yeast Res 16:.

Mahesan, A., G. Kamila, P. Choudhary, P. Jauhari, B. Chakrabarty, A. Kumar, and S. Gulati. (2023). Novel Gene Mutation: A Rare Case of Delayed Myelination with Dysthyroidism,v Allan-Herndon-Dudley Syndrome. Neurol India 71: 1282-1283.

Mahrhold, S., A. Rummel, H. Bigalke, B. Davletov, and T. Binz. (2006). The synaptic vesicle protein 2C mediates the uptake of botulinum neurotoxin A into phrenic nerves. FEBS Lett. 580: 2011-2014.

Majumder, P., S. Ahmed, P. Ahuja, A. Athreya, R. Ranjan, and A. Penmatsa. (2023). Cryo-EM structure of antibacterial efflux transporter QacA from Staphylococcus aureus reveals a novel extracellular loop with allosteric role. EMBO. J. e113418. [Epub: Ahead of Print]

Majumder, P., S. Khare, A. Athreya, N. Hussain, A. Gulati, and A. Penmatsa. (2019). Dissection of Protonation Sites for Antibacterial Recognition and Transport in QacA, a Multi-Drug Efflux Transporter. J. Mol. Biol. [Epub: Ahead of Print]

Makuc, J., S. Paiva, M. Schauen, R. Krämer, B. André, M. Casal, C. Leão, and E. Boles. (2001). The putative monocarboxylate permeases of the yeast Saccharomyces cerevisiae do not transport monocarboxylic acids across the plasma membrane. Yeast 18: 1131-1143.

Mallik, D., S. Pal, and A.S. Ghosh. (2018). Involvement of AmpG in mediating a dynamic relationship between serine β-lactamase induction and biofilm-forming ability of Escherichia coli. FEMS Microbiol. Lett. 365:.

Mallonee, D.H. and P.B. Hylemon. (1996). Sequencing and expression of a gene encoding a bile acid transporter from Eubacterium sp. strain VPI 12708. J. Bacteriol. 178: 7053-7058.

Mandal A., Kumar A., Singh A., Lynn AM., Kapoor K. and Prasad R. (2012). A key structural domain of the Candida albicans Mdr1 protein. Biochem J. 445(3):313-22.

Mandal, A.K. and D.B. Mount. (2019). Interaction Between ITM2B and GLUT9 Links Urate Transport to Neurodegenerative Disorders. Front Physiol 10: 1323.

Manel, N., F.J. Kim, S. Kinet, N. Taylor, M. Sitbon, and J.-L. Battini. (2003). The ubiquitous glucose transporter GLUT-1 is a receptor for HTLV. Cell 115: 449-459.

Manolescu, A., A.M. Salas-Burgos, J. Fischbarg, and C.I. Cheeseman. (2005). Identification of a hydrophobic residue as a key determinant of fructose transport by the facilitative hexose transporter SLC2A7 (GLUT7). J. Biol. Chem. 280: 42978-42983.

Mansfield, T.A., N.P. Schultes, and G.S. Mourad. (2009). AtAzg1 and AtAzg2 comprise a novel family of purine transporters in Arabidopsis. FEBS Lett. 583: 481-486.

Marchi, E., T. Lodi, and C. Donnini. (2007). KNQ1, a Kluyveromyces lactis gene encoding a transmembrane protein, may be involved in iron homeostasis. FEMS Yeast Res 7: 715-721.

Mardones, L., V. Ormazabal, X. Romo, C. Jaña, P. Binder, E. Peña, M. Vergara, and F.A. Zúñiga. (2011). The glucose transporter-2 (GLUT2) is a low affinity dehydroascorbic acid transporter. Biochem. Biophys. Res. Commun. 410: 7-12.

Marger, M.D. and M.H. Saier, Jr. (1993). A major superfamily of transmembrane facilitators that catalyse uniport, symport and antiport. Trends Biochem. Sci. 18: 13-20.

Mariotta L., Ramadan T., Singer D., Guetg A., Herzog B., Stoeger C., Palacin M., Lahoutte T., Camargo SM. and Verrey F. (2012). T-type amino acid transporter TAT1 (Slc16a10) is essential for extracellular aromatic amino acid homeostasis control. J Physiol. 590(Pt 24):6413-24.

Marklevitz, J. and L.K. Harris. (2016). Prediction driven functional annotation of hypothetical proteins in the major facilitator superfamily of S. aureus NCTC 8325. Bioinformation 12: 254-262.

Martín-Venegas, R., M.J. Rodríguez-Lagunas, P.A. Geraert, and R. Ferrer. (2007). Monocarboxylate transporter 1 mediates DL-2-Hydroxy-(4-methylthio)butanoic acid transport across the apical membrane of Caco-2 cell monolayers. J. Nutr. 137: 49-54.

Martin, V.J. and W.W. Mohn. (2000). Genetic investigation of the catabolic pathway for degradation of abietane diterpenoids by Pseudomonas abietaniphila BKME-9. J. Bacteriol. 182: 3784-3793.

Martinez-Garriga, B., T. Vinuesa, J. Hernandez-Borrell, and M. Viñas. (2007). The contribution of efflux pumps to quinolone resistance in Streptococcus pneumoniae clinical isolates. Int. J. Med. Microbiol. 297: 187-195.

Martinez-Jéhanne, V., L. du Merle, C. Bernier-Fébreau, C. Usein, A. Gassama-Sow, A.A. Wane, M. Gouali, M. Damian, A. Aïdara-Kane, Y. Germani, A. Fontanet, B. Coddeville, Y. Guérardel, and C. Le Bouguénec. (2009). Role of deoxyribose catabolism in colonization of the murine intestine by pathogenic Escherichia coli strains. Infect. Immun. 77: 1442-1450.

Martinussen, J., C. Sørensen, C.B. Jendresen, and M. Kilstrup. (2010). Two nucleoside transporters in Lactococcus lactis with different substrate specificities. Microbiology 156: 3148-3157.

Maruyama, S.Y., M. Ito, Y. Ikami, Y. Okitsu, C. Ito, K. Toshimori, W. Fujii, and K. Yogo. (2016). A critical role of solute carrier 22a14 in sperm motility and male fertility in mice. Sci Rep 6: 36468.

Massa López, D., M. Thelen, F. Stahl, C. Thiel, A. Linhorst, M. Sylvester, I. Hermanns-Borgmeyer, R. Lüllmann-Rauch, W. Eskild, P. Saftig, and M. Damme. (2019). The lysosomal transporter MFSD1 is essential for liver homeostasis and critically depends on its accessory subunit GLMP. Elife 8:.

Masureel M., Martens C., Stein RA., Mishra S., Ruysschaert JM., Mchaourab HS. and Govaerts C. (2014). Protonation drives the conformational switch in the multidrug transporter LmrP. Nat Chem Biol. 10(2):149-55.

Matherly LH., Wilson MR. and Hou Z. (2014). The major facilitative folate transporters solute carrier 19A1 and solute carrier 46A1: biology and role in antifolate chemotherapy of cancer. Drug Metab Dispos. 42(4):632-49.

Matherly, L.H., M. Schneider, A. Gangjee, and Z. Hou. (2022). Biology and therapeutic applications of the proton-coupled folate transporter. Expert Opin Drug Metab Toxicol 1-12. [Epub: Ahead of Print]

Mathews, E.A., G.P. Mullen, J. Hodgkin, J.S. Duerr, and J.B. Rand. (2012). Genetic interactions between UNC-17/VAChT and a novel transmembrane protein in Caenorhabditis elegans. Genetics 192: 1315-1325.

Mathiesen, B.K., L.M. Miyakoshi, C.R. Cederroth, E. Tserga, C. Versteegh, P.A.R. Bork, N.L. Hauglund, R.S. Gomolka, Y. Mori, N.K. Edvall, S. Rouse, K. Møllgård, J.R. Holt, M. Nedergaard, and B. Canlon. (2023). Delivery of gene therapy through a cerebrospinal fluid conduit to rescue hearing in adult mice. Sci Transl Med 15: eabq3916.

Maulén, N.P., E.A. Henríquez, S. Kempe, J.G. Cárcamo, A. Schmid-Kotsas, M. Bachem, A. Grünert, M.E. Bustamante, F. Nualart, and J.C. Vera. (2003). Up-regulation and polarized expression of the sodium-ascorbic acid transporter SVCT1 in post-confluent differentiated CaCo-2 cells. J. Biol. Chem. 278: 9035-9041.

Mauri, A., A. Duse, G. Palm, R. Previtali, S.M. Bova, S. Olivotto, S. Benedetti, F. Coscia, P. Veggiotti, and C. Cereda. (2022). Molecular Genetics of GLUT1DS Italian Pediatric Cohort: 10 Novel Disease-Related Variants and Structural Analysis. Int J Mol Sci 23:.

Mayerl, S., M. Schmidt, D. Doycheva, V.M. Darras, S.S. Hüttner, A. Boelen, T.J. Visser, C. Kaether, H. Heuer, and J. von Maltzahn. (2018). Thyroid Hormone Transporters MCT8 and OATP1C1 Control Skeletal Muscle Regeneration. Stem Cell Reports. [Epub: Ahead of Print]

McClung, D.J., A. Calixto, M.N. Mosera, R. Kumar, E.L. Neidle, and K.T. Elliott. (2016). Novel heterologous bacterial system reveals enhanced susceptibility to DNA damage mediated by yqgF, a nearly ubiquitous and often essential gene. Microbiology 162: 1808-1821.

McCulloch, K.A., Y.B. Qi, S. Takayanagi-Kiya, Y. Jin, and S.J. Cherra, 3rd. (2017). Novel Mutations in Synaptic Transmission Genes Suppress Neuron.al Hyperexcitation in. G3 (Bethesda) 7: 2055-2063.

McGee, S.L. and M. Hargreaves. (2006). Exercise and skeletal muscle glucose transporter 4 expression: molecular mechanisms. Clin Exp Pharmacol Physiol 33: 395-399.

Meier, A., H. Erler, and E. Beitz. (2018). Targeting Channels and Transporters in Protozoan Parasite Infections. Front Chem 6: 88.

Meixner, E., U. Goldmann, V. Sedlyarov, S. Scorzoni, M. Rebsamen, E. Girardi, and G. Superti-Furga. (2020). A substrate-based ontology for human solute carriers. Mol Syst Biol 16: e9652.

Meyer, K., M. Kirchner, B. Uyar, J.Y. Cheng, G. Russo, L.R. Hernandez-Miranda, A. Szymborska, H. Zauber, I.M. Rudolph, T.E. Willnow, A. Akalin, V. Haucke, H. Gerhardt, C. Birchmeier, R. Kühn, M. Krauss, S. Diecke, J.M. Pascual, and M. Selbach. (2018). Mutations in Disordered Regions Can Cause Disease by Creating Dileucine Motifs. Cell. [Epub: Ahead of Print]

Meyer, M.J., A. Tuerkova, S. Römer, C. Wenzel, T. Seitz, J. Gaedcke, S. Oswald, J. Brockmöller, B. Zdrazil, and M.V. Tzvetkov. (2020). Drug Metab Dispos. [Epub: Ahead of Print]

Meyer, M.J., P.C.F. Schreier, M. Basaran, S. Vlasova, T. Seitz, J. Brockmöller, B. Zdrazil, and M.V. Tzvetkov. (2022). Amino acids in transmembrane helix 1 confer major functional differences between human and mouse orthologs of the polyspecific membrane transporter OCT1. J. Biol. Chem. 101974. [Epub: Ahead of Print]

Meyer-Tönnies, M.J. and M.V. Tzvetkov. (2023). The end of the beginning in understanding SLC22 polyspecificity. Trends Pharmacol Sci 44: 397-399.

Michel, L., A. Bachelard, and C. Reimmann. (2007). Ferripyochelin uptake genes are involved in pyochelin-mediated signalling in Pseudomonas aeruginosa. Microbiology 153: 1508-1518.

Miethke, M., S. Schmidt, and M.A. Marahiel. (2008). The major facilitator superfamily-type transporter YmfE and the multidrug-efflux activator Mta mediate bacillibactin secretion in Bacillus subtilis. J. Bacteriol. 190: 5143-5152.

Miller, A.J., X. Fan, M. Orsel, S.J. Smith, and D.M. Wells. (2007). Nitrate transport and signalling. J Exp Bot 58: 2297-306.

Miura, D., N. Anzai, P. Jutabha, S. Chanluang, X. He, T. Fukutomi, and H. Endou. (2011). Human urate transporter 1 (hURAT1) mediates the transport of orotate. J. Physiol. Sci 61: 253-257.

Miyaji, T., T. Kuromori, Y. Takeuchi, N. Yamaji, K. Yokosho, A. Shimazawa, E. Sugimoto, H. Omote, J.F. Ma, K. Shinozaki, and Y. Moriyama. (2015). AtPHT4;4 is a chloroplast-localized ascorbate transporter in Arabidopsis. Nat Commun 6: 5928.

Monte, J.C., M.A. Nagle, S.A. Eraly, and S.K. Nigam. (2004). Identification of a novel murine organic anion transporter family member, OAT6, expressed in olfactory mucosa. Biochem. Biophys. Res. Commun. 323: 429-436.

Montel-Hagen, A., S. Kinet, N. Manel, C. Mongellaz, R. Prohaska, J.L. Battini, J. Delaunay, M. Sitbon, and N. Taylor. (2008). Erythrocyte Glut1 triggers dehydroascorbic acid uptake in mammals unable to synthesize vitamin C. Cell 132: 1039-1048.

Moore, R.E., Y. Kim, and C.C. Philpott. (2003). The mechanism of ferrichrome transport through Arn1p and its metabolism in Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. USA 100: 5664-5669.

Mor, A.L., T.W. Kaminski, M. Karbowska, and D. Pawlak. (2018). New insight into organic anion transporters from the perspective of potentially important interactions and drugs toxicity. J. Physiol. Pharmacol 69:.

Moraes, T.F. and R.A. Reithmeier. (2012). Membrane transport metabolons. Biochim. Biophys. Acta. 1818: 2687-2706.

Moraleda-Muñoz, A., J. Pérez, A.L. Extremera, and J. Muñoz-Dorado. (2010). Differential regulation of six heavy metal efflux systems in the response of Myxococcus xanthus to copper. Appl. Environ. Microbiol. 76: 6069-6076.

Morin, P., C. Sagné, and B. Gasnier. (2004). Functional characterization of wild-type and mutant human sialin. EMBO. J. 23: 4560-4570.

Morishita, M. and J. Engebrecht. (2008). Sorting signals within the Saccharomyces cerevisiae sporulation-specific dityrosine transporter, Dtr1p, C terminus promote Golgi-to-prospore membrane transport. Eukaryot. Cell. 7: 1674-1684.

Morrice, N., S. Vainio, K. Mikkola, L. van Aalten, J.R. Gallagher, M.L.J. Ashford, A.D. McNeilly, R.J. McCrimmon, A. Grosfeld, P. Serradas, J. Koffert, E.R. Pearson, P. Nuutila, and C. Sutherland. (2023). Metformin increases the uptake of glucose into the gut from the circulation in high-fat diet-fed male mice, which is enhanced by a reduction in whole-body Slc2a2 expression. Mol Metab 77: 101807. [Epub: Ahead of Print]

Moschen I., Broer A., Galic S., Lang F. and Broer S. (2012). Significance of short chain fatty acid transport by members of the monocarboxylate transporter family (MCT). Neurochem Res. 37(11):2562-8.

Mueckler, M. and C. Makepeace. (2004). Analysis of transmembrane segment 8 of the GLUT1 glucose transporter by cysteine-scanning mutagenesis and substituted cysteine accessibility. J. Biol. Chem. 279: 10494-10499.

Mueckler, M. and C. Makepeace. (2009). Model of the exofacial substrate-binding site and helical folding of the human Glut1 glucose transporter based on scanning mutagenesis. Biochemistry 48: 5934-5942.

Murphy, P.J., S.P. Trenz, W. Grzemski, F.J. De Bruijn, and J. Schell. (1993). The Rhizobium meliloti rhizopine mos locus is a mosaic structure facilitating its symbiotic regulation. J. Bacteriol. 175: 5193-5204.

Naftalin, R.J. (2008). Osmotic water transport with glucose in GLUT2 and SGLT. Biophys. J. 94: 3912-3923.

Nagakubo, S., K. Nishino, T. Hirata, and A. Yamaguchi. (2002). The putative response regulator BaeR stimulates multidrug resistance of Escherichia coli via a novel multidrug exporter system, MdtABC. J. Bacteriol. 184: 4161-4167.

Nagarathinam, K., F. Jaenecke, Y. Nakada-Nakura, Y. Hotta, K. Liu, S. Iwata, M.T. Stubbs, N. Nomura, and M. Tanabe. (2017). The multidrug-resistance transporter MdfA from Escherichia coli: crystallization and X-ray diffraction analysis. Acta Crystallogr F Struct Biol Commun 73: 423-430.

Naidu, V., B. Shah, C. Maher, I.T. Paulsen, and K.A. Hassan. (2023). AadT, a new weapon in fight against antibiotics. Microbiology (Reading) 169:.

Nair, A.V., H. Singh, S. Raturi, A. Neuberger, Z. Tong, N. Ding, K. Agboh, and H.W. van Veen. (2016). Relocation of active site carboxylates in major facilitator superfamily multidrug transporter LmrP reveals plasticity in proton interactions. Sci Rep 6: 38052.

Nakano, Y., K. Fujitani, J. Kurihara, J. Ragan, K. Usui-Aoki, L. Shimoda, T. Lukacsovich, K. Suzuki, M. Sezaki, Y. Sano, R. Ueda, W. Awano, M. Kaneda, M. Umeda, and D. Yamamoto. (2001). Mutations in the novel membrane protein spinster interfere with programmed cell death and cause neural degeneration in Drosophila melanogaster. Mol. Cell. Biol. 21: 3775-3788.

Nakata, T., T. Matsui, K. Kobayashi, Y. Kobayashi, and N. Anzai. (2013). Organic cation transporter 2 (SLC22A2), a low-affinity and high-capacity choline transporter, is preferentially enriched on synaptic vesicles in cholinergic neurons. Neuroscience 252: 212-221.

Nakayama, Y., N. Mukai, G. Kreitzer, P. Patwari, and J. Yoshioka. (2022). Interaction of ARRDC4 With GLUT1 Mediates Metabolic Stress in the Ischemic Heart. Circ Res 131: 510-527.

Nancolas, B., R.B. Sessions, and A.P. Halestrap. (2015). Identification of key binding site residues of MCT1 for AR-C155858 reveals the molecular basis of its isoform selectivity. Biochem. J. 466: 177-188.

Naseer, N., J.A. Shapiro, and M. Chander. (2014). RNA-Seq analysis reveals a six-gene SoxR regulon in Streptomyces coelicolor. PLoS One 9: e106181.

Naula, C.M., F.M. Logan, P.E. Wong, M.P. Barrett, and R.J. Burchmore. (2010). A glucose transporter can mediate ribose uptake: definition of residues that confer substrate specificity in a sugar transporter. J. Biol. Chem. 285: 29721-29728.

Nazish, I., A. Mamais, A. Mallach, C. Bettencourt, A. Kaganovich, T. Warner, J. Hardy, P.A. Lewis, J. Pocock, M.R. Cookson, and R. Bandopadhyay. (2023). Differential LRRK2 signalling and gene expression in WT-LRRK2 and G2019S-LRRK2 mouse microglia treated with zymosan and MLi2. bioRxiv.

Nałęcz, K.A. and M.J. Nałęcz. (2017). [Carnitine - mitochondria and beyond]. Postepy Biochem 62: 85-93.

Nele Bourgeois, M.A., S.L. Van Herck, P. Vancamp, J. Delbaere, C. Zevenbergen, S. Kersseboom, V.M. Darras, and T.J. Visser. (2016). CHARACTERIZATION OF CHICKEN THYROID HORMONE TRANSPORTERS. Endocrinology en20152025. [Epub: Ahead of Print]

Nemoz, G., J. Robert-Baudouy, and F. Stoeber. (1976). Physiological and genetic regulation of the aldohexuronate transport system in Escherichia coli. J. Bacteriol. 127: 706-718.

Nesper, J., A. Brosig, P. Ringler, G.J. Patel, S.A. Müller, J.H. Kleinschmidt, W. Boos, K. Diederichs, and W. Welte. (2008). Omp85(Tt) from Thermus thermophilus HB27: an ancestral type of the Omp85 protein family. J. Bacteriol. 190: 4568-4575.

Ng, T.S., S.Y. Chew, P. Rangasamy, M.N. Mohd Desa, D. Sandai, P.P. Chong, and L.T. Than. (2015). SNF3 as High Affinity Glucose Sensor and Its Function in Supporting the Viability of Candida glabrata under Glucose-Limited Environment. Front Microbiol 6: 1334.

Nguyen, A.Q., J. Schneider, and V.F. Wendisch. (2015). Elimination of polyamine N-acetylation and regulatory engineering improved putrescine production by Corynebacterium glutamicum. J Biotechnol 201: 75-85.

Nichols, N.N. and C.S. Harwood. (1997). PcaK, a high-affinity permease for the aromatic compounds 4-hydroxybenzoate and protocatechuate from Pseudomonas putida. J. Bacteriol. 179: 5056-5061.

Nigam, S.K. (2015). What do drug transporters really do? Nat Rev Drug Discov 14: 29-44.

Nijnik, A., S. Clare, C. Hale, J. Chen, C. Raisen, L. Mottram, M. Lucas, J. Estabel, E. Ryder, H. Adissu, , N.C. Adams, R. Ramirez-Solis, J.K. White, K.P. Steel, G. Dougan, and R.E. Hancock. (2012). The role of sphingosine-1-phosphate transporter Spns2 in immune system function. J Immunol 189: 102-111.

Nilsson, D., M. Pettersson, P. Gustavsson, A. Förster, W. Hofmeister, J. Wincent, V. Zachariadis, B.M. Anderlid, A. Nordgren, O. Mäkitie, V. Wirta, M. Käller, F. Vezzi, J.R. Lupski, M. Nordenskjöld, E.S. Lundberg, C.M.B. Carvalho, and A. Lindstrand. (2017). Whole-Genome Sequencing of Cytogenetically Balanced Chromosome Translocations Identifies Potentially Pathological Gene Disruptions and Highlights the Importance of Microhomology in the Mechanism of Formation. Hum Mutat 38: 180-192.

Nishino, K. and A. Yamaguchi. (2001). Analysis of a complete library of putative drug transporter genes in Escherichia coli. J. Bacteriol. 183: 5803-5812.

Niu, C., G.A. Payne, and C.P. Woloshuk. (2016). Involvement of FST1 from Fusarium verticillioides in virulence and transport of inositol. Mol Plant Pathol. [Epub: Ahead of Print]

Niu, Y., R. Liu, C. Guan, Y. Zhang, Z. Chen, S. Hoerer, H. Nar, and L. Chen. (2021). Structural basis of inhibition of the human SGLT2-MAP17 glucose transporter. Nature. [Epub: Ahead of Print]

Nobre, A., C. Lucas, and C. Leão. (1999). Transport and utilization of hexoses and pentoses in the halotolerant yeast Debaryomyces hansenii. Appl. Environ. Microbiol. 65: 3594-3598.

Nomura N., Verdon G., Kang HJ., Shimamura T., Nomura Y., Sonoda Y., Hussien SA., Qureshi AA., Coincon M., Sato Y., Abe H., Nakada-Nakura Y., Hino T., Arakawa T., Kusano-Arai O., Iwanari H., Murata T., Kobayashi T., Hamakubo T., Kasahara M., Iwata S. and Drew D. (2015). Structure and mechanism of the mammalian fructose transporter GLUT5. Nature. 526(7573):397-401.

Norholm, M.H., H.H. Nour-Eldin, P. Brodersen, J. Mundy, and B.A. Halkier. (2006). Expression of the Arabidopsis high-affinity hexose transporter STP13 correlates with programmed cell death. FEBS Lett. 17: 2381-2387.

Normant, V., A. Brault, M. Avino, T. Mourer, T. Vahsen, J. Beaudoin, and S. Labbé. (2020). Hemeprotein Tpx1 interacts with cell-surface heme transporter Str3 in Schizosaccharomyces pombe. Mol. Microbiol. [Epub: Ahead of Print]

Notariale, R., E. Längst, P. Perrone, D. Crettaz, M. Prudent, and C. Manna. (2022). Effect of Mercury on Membrane Proteins, Anionic Transport and Cell Morphology in Human Erythrocytes. Cell Physiol Biochem 56: 500-513.

Nunvar, J., A.M. Hogan, S. Buroni, S. Savina, V. Makarov, S.T. Cardona, and P. Drevinek. (2019). The Effect of 2-Thiocyanatopyridine Derivative 11026103 on : Resistance Mechanisms and Systemic Impact. Antibiotics (Basel) 8:.

Nygaard, P. and H.H. Saxild. (2005). The purine efflux pump PbuE in Bacillus subtilis modulates expression of the PurR and G-box (XptR) regulons by adjusting the purine base pool size. J. Bacteriol. 187: 791-794.

Nørholm, M.H. and G. Dandanell. (2001). Specificity and topology of the Escherichia coli xanthosine permease, a representative of the NHS subfamily of the major facilitator superfamily. J. Bacteriol. 183: 4900-4904.

Ogasawara, H., S. Ohe, and A. Ishihama. (2015). Role of transcription factor NimR (YeaM) in sensitivity control of Escherichia coli to 2-nitroimidazole. FEMS Microbiol. Lett. 362: 1-8.

Ohki, R. and K. Tateno. (2004). Increased stability of bmr3 mRNA results in a multidrug-resistant phenotype in Bacillus subtilis. J. Bacteriol. 186: 7450-7455.

Ohki, R. and M. Murata. (1997). bmr3, a third multidrug transporter gene of Bacillus subtilis. J. Bacteriol. 179: 1423-1427.

Ojeda, A.M., N.G. Kolmakova, and S.M. Parsons. (2004). Acetylcholine binding site in the vesicular acetylcholine transporter. Biochemistry 43: 11163-11174.

Oku, Y., K. Kurokawa, N. Ichihashi, and K. Sekimizu. (2004). Characterization of the Staphylococcus aureus mprF gene, involved in lysinylation of phosphatidylglycerol. Microbiology 150: 45-51.

Oliveira, I.H.R., H.C.P. Figueiredo, C.P. Rezende, T. Verano-Braga, M.N. Melo-Braga, J.L. Reis Cunha, and H.M. de Andrade. (2020). Assessing the composition of the plasma membrane of Leishmania (Leishmania) infantum and L. (L.) amazonensis using label-free proteomics. Exp Parasitol 218: 107964. [Epub: Ahead of Print]

Oliveira-Tintino, C.D.M., D.F. Muniz, C.R.D.S. Barbosa, R.L.S. Pereira, I.M. Begnini, R.A. Rebelo, L.E.D. Silva, S.L. Mireski, M.C. Nasato, M.I.L. Krautler, P.S. Pereira, J.G.M.D. Costa, F.F.G. Rodrigues, A.M.R. Teixeira, J. Ribeiro-Filho, S.R. Tintino, I.R.A. de Menezes, H.D.M. Coutinho, and T.G.D. Silva. (2021). The 1,8-naphthyridines sulfonamides are NorA efflux pump inhibitors. J Glob Antimicrob Resist 24: 233-240.

Omote, H., T. Miyaji, N. Juge, and Y. Moriyama. (2011). Vesicular neurotransmitter transporter: bioenergetics and regulation of glutamate transport. Biochemistry 50: 5558-5565.

Ostash, I., B. Ostash, A. Luzhetskyy, A. Bechthold, S. Walker, and V. Fedorenko. (2008). Coordination of export and glycosylation of landomycins in Streptomyces cyanogenus S136. FEMS Microbiol. Lett. 285: 195-202.

Ovens, M.J., C. Manoharan, M.C. Wilson, C.M. Murray, and A.P. Halestrap. (2010). The inhibition of monocarboxylate transporter 2 (MCT2) by AR-C155858 is modulated by the associated ancillary protein. Biochem. J. 431: 217-225.

Ozcan, S. and M. Johnston. (1999). Function and regulation of yeast hexose transporters. Microbiol. Mol. Biol. Rev. 63: 554-569.

Ozturk, T.N., C. Coumoundouros, D.E. Culham, and J.M. Wood. (2023). Structural Determinants and Functional Significance of Dimerization for Osmosensing Transporter ProP in. Biochemistry 62: 118-133.

Ozturk, T.N., D.E. Culham, L. Tempelhagen, J.M. Wood, and G. Lamoureux. (2020). Salt-Dependent Interactions between the C-Terminal Domain of Osmoregulatory Transporter ProP of and the Lipid Membrane. J Phys Chem B 124: 8209-8220.

Périchon, B., P. Bogaerts, T. Lambert, L. Frangeul, P. Courvalin, and M. Galimand. (2008). Sequence of conjugative plasmid pIP1206 mediating resistance to aminoglycosides by 16S rRNA methylation and to hydrophilic fluoroquinolones by efflux. Antimicrob. Agents Chemother. 52: 2581-2592.

Périchon, B., P. Courvalin, and M. Galimand. (2007). Transferable resistance to aminoglycosides by methylation of G1405 in 16S rRNA and to hydrophilic fluoroquinolones by QepA-mediated efflux in Escherichia coli. Antimicrob. Agents Chemother. 51: 2464-2469.

Packer, M., C.S. Wilcox, and J.M. Testani. (2023). Critical Analysis of the Effects of SGLT2 Inhibitors on Renal Tubular Sodium, Water and Chloride Homeostasis and Their Role in Influencing Heart Failure Outcomes. Circulation 148: 354-372.

Pamp, S.J., M. Gjermansen, H.K. Johansen, and T. Tolker-Nielsen. (2008). Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes. Mol. Microbiol. 68: 223-240.

Pan PY., Marrs J. and Ryan TA. (2015). Vesicular glutamate transporter 1 orchestrates recruitment of other synaptic vesicle cargo proteins during synaptic vesicle recycling. J Biol Chem. 290(37):22593-601.

Pan, C.J., S.Y. Chen, H.S. Jun, S.R. Lin, B.C. Mansfield, and J.Y. Chou. (2011). SLC37A1 and SLC37A2 are phosphate-linked, glucose-6-phosphate antiporters. PLoS One 6: e23157.

Pan, W., R.S. Godoy, D.P. Cook, A.L. Scott, C.A. Nurse, and M.G. Jonz. (2022). Single-cell transcriptomic analysis of neuroepithelial cells and other cell types of the gills of zebrafish (Danio rerio) exposed to hypoxia. Sci Rep 12: 10144.

Panja, A.S., A. Sarkar, R. Biswas, B. Bandyopadhyay, and R. Bandopadhyay. (2019). Modification of drug-binding proteins associated with the efflux pump in MDR-MTB in course of evolution: an unraveled clue based on in silico approach. J Antibiot (Tokyo) 72: 282-290.

Pao, S.S., I.T. Paulsen, and M.H. Saier, Jr. (1998). The major facilitator superfamily. Microbiol. Mol. Biol. Rev. 62: 1-32.

Paolini, R., C. Moore, T. Matthyssen, N. Cirillo, M. McCullough, C.S. Farah, H. Botha, T. Yap, and A. Celentano. (2022). Transcriptional regulation of glucose transporters in human oral squamous cell carcinoma cells. J Oral Pathol Med 51: 679-683.

Papakonstantinou, E., D. Vlachakis, T. Thireou, P.G. Vlachoyiannopoulos, and E. Eliopoulos. (2021). A Holistic Evolutionary and 3D Pharmacophore Modelling Study Provides Insights into the Metabolism, Function, and Substrate Selectivity of the Human Monocarboxylate Transporter 4 (hMCT4). Int J Mol Sci 22:.

Parche, S., M. Beleut, E. Rezzonico, D. Jacobs, F. Arigoni, F. Titgemeyer, and I. Jankovic. (2006). Lactose-over-glucose preference in Bifidobacterium longum NCC2705: glcP, encoding a glucose transporter, is subject to lactose repression. J. Bacteriol. 188: 1260-1265.

Park, J.S., S.J. Lee, H.G. Rhie, and H.S. Lee. (2008). Characterization of a chromosomal nickel resistance determinant from Klebsiella oxytoca CCUG 15788. J Microbiol Biotechnol 18: 1040-1043.

Park, J.T. and T. Uehara. (2008). How bacteria consume their own exoskeletons (turnover and recycling of cell wall peptidoglycan). Microbiol. Mol. Biol. Rev. 72: 211-27, table of contents.

Park, J.T., D. Raychaudhuri, H. Li, S. Normark, and D. Mengin-Lecreulx. (1998). MppA, a periplasmic binding protein essential for import of the bacterial cell wall peptide L-alanyl-γ-D-glutamyl-meso-diaminopimelate. J. Bacteriol. 180: 1215-1223.

Park, S.J., C.P. Smith, R.R. Wilbur, C.P. Cain, S.R. Kallu, S. Valasapalli, A. Sahoo, M.R. Guda, A.J. Tsung, and K.K. Velpula. (2018). An overview of MCT1 and MCT4 in GBM: small molecule transporters with large implications. Am J Cancer Res 8: 1967-1976.

Park, T.J., J. Reznick, B.L. Peterson, G. Blass, D. Omerbašić, N.C. Bennett, P.H.J.L. Kuich, C. Zasada, B.M. Browe, W. Hamann, D.T. Applegate, M.H. Radke, T. Kosten, H. Lutermann, V. Gavaghan, O. Eigenbrod, V. Bégay, V.G. Amoroso, V. Govind, R.D. Minshall, E.S.J. Smith, J. Larson, M. Gotthardt, S. Kempa, and G.R. Lewin. (2017). Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat. Science 356: 307-311.

Pascual, J.M., D. Wang, R. Yang, L. Shi, H. Yang, and D.C. De Vivo. (2008). Structural Signatures and Membrane Helix 4 in GLUT1: INFERENCES FROM HUMAN BLOOD-BRAIN GLUCOSE TRANSPORT MUTANTS. J. Biol. Chem. 283: 16732-16742.

Patching, S.G., G. Psakis, S.A. Baldwin, J. Baldwin, P.J. Henderson, and D.A. Middleton. (2008). Relative substrate affinities of wild-type and mutant forms of the Escherichia coli sugar transporter GalP determined by solid-state NMR. Mol. Membr. Biol. 25: 474-484.

Patching, S.G., S.A. Baldwin, A.D. Baldwin, J.D. Young, M.P. Gallagher, P.J. Henderson, and R.B. Herbert. (2005). The nucleoside transport proteins, NupC and NupG, from Escherichia coli: specific structural motifs necessary for the binding of ligands. Org Biomol Chem 3: 462-470.

Patel, N., H. Alkuraya, S.S. Alzahrani, S.R. Nowailaty, M.Z. Seidahmed, A. Alhemidan, T. Ben-Omran, N.G. Ghazi, A. Al-Aqeel, M. Al-Owain, H.I. Alzaidan, E. Faqeih, W. Kurdi, Z. Rahbeeni, N. Ibrahim, F. Abdulwahab, M. Hashem, R. Shaheen, M. Abouelhoda, D. Monies, A.O. Khan, M.A. Aldahmesh, and F.S. Alkuraya. (2018). Mutations in known disease genes account for the majority of autosomal recessive retinal dystrophies. Clin Genet 94: 554-563.

Patrick PS., Lyons SK., Rodrigues TB. and Brindle KM. (2014). Oatp1 enhances bioluminescence by acting as a plasma membrane transporter for D-luciferin. Mol Imaging Biol. 16(5):626-34.

Paul, S., K.O. Alegre, S.R. Holdsworth, M. Rice, J.A. Brown, P. McVeigh, S.M. Kelly, and C.J. Law. (2014). A single-component multidrug transporter of the major facilitator superfamily is part of a network that protects Escherichia coli from bile salt stress. Mol. Microbiol. 92: 872-884.

Paulsen, I.T., M.H. Brown, and R.A. Skurray. (1996). Proton-dependent multidrug efflux systems. Microbiol. Rev. 60: 575-608.

Paulsen, I.T., S. Chauvaux, P. Choi, and M.H. Saier, Jr. (1998). Characterization of glucose-specific catabolite repression-resistant mutants of Bacillus subtilis: identification of a novel hexose:H+ symporter. J. Bacteriol. 180: 498-504.

Paulsen, P.A., T.F. Custódio, and B.P. Pedersen. (2019). Crystal structure of the plant symporter STP10 illuminates sugar uptake mechanism in monosaccharide transporter superfamily. Nat Commun 10: 407.

Pavón, L.R., F. Lundh, B. Lundin, A. Mishra, B.L. Persson, and C. Spetea. (2008). Arabidopsis ANTR1 is a thylakoid Na+-dependent phosphate transporter: functional characterization in Escherichia coli. J. Biol. Chem. 283: 13520-13527.

Pearson, S.M., A.G. Griffiths, P. Maclean, A.C. Larking, S.W. Hong, R. Jauregui, P. Miller, C.M. McKenzie, P.J. Lockhart, J.A. Tate, J.L. Ford, and M.J. Faville. (2022). Outlier analyses and genome-wide association study identify and as candidate genes for foliar water-soluble carbohydrate accumulation in. Front Plant Sci 13: 1095359.

Pedersen, B.P., H. Kumar, A.B. Waight, A.J. Risenmay, Z. Roe-Zurz, B.H. Chau, A. Schlessinger, M. Bonomi, W. Harries, A. Sali, A.K. Johri, and R.M. Stroud. (2013). Crystal structure of a eukaryotic phosphate transporter. Nature 496: 533-536.

Peekhaus, N. and T. Conway. (1998). What’s for dinner?: Entner-Doudoroff metabolism in Escherichia coli. J. Bacteriol 180: 3495-3502.

Pegg, A.E. and A.J. Michael. (2010). Spermine synthase. Cell Mol Life Sci 67: 113-121.

Pelis, R.M., X. Zhang, Y. Dangprapai, and S.H. Wright. (2006). Cysteine accessibility in the hydrophilic cleft of human organic cation transporter 2. J. Biol. Chem. 281: 35272-35280.

Pelka, K., D. Bertheloot, E. Reimer, K. Phulphagar, S.V. Schmidt, A. Christ, R. Stahl, N. Watson, K. Miyake, N. Hacohen, A. Haas, M.M. Brinkmann, A. Marshak-Rothstein, F. Meissner, and E. Latz. (2018). The Chaperone UNC93B1 Regulates Toll-like Receptor Stability Independently of Endosomal TLR Transport. Immunity 48: 911-922.e7.

Pelka, K., K. Phulphagar, J. Zimmermann, R. Stahl, J.L. Schmid-Burgk, T. Schmidt, J.H. Spille, L.I. Labzin, S. Agrawal, E.R. Kandimalla, J.L. Casanova, V. Hornung, A. Marshak-Rothstein, S. Höning, and E. Latz. (2014). Cutting edge: the UNC93B1 tyrosine-based motif regulates trafficking and TLR responses via separate mechanisms. J Immunol 193: 3257-3261.

Pelletier, B., J. Beaudoin, C.C. Philpott, and S. Labbé. (2003). Fep1 represses expression of the fission yeast Schizosaccharomyces pombe siderophore-iron transport system. Nucleic Acids Res 31: 4332-4344.

Pellizzaro A., Clochard T., Planchet E., Limami AM. and Morere-Le Paven MC. (2015). Identification and molecular characterization of Medicago truncatula NRT2 and NAR2 families. Physiol Plant. 154(2):256-69.

Pendse, P.Y., B.R. Brooks, and J.B. Klauda. (2010). Probing the periplasmic-open state of lactose permease in response to sugar binding and proton translocation. J. Mol. Biol. 404: 506-521.

Peng, Y., S. Kumar, R.L. Hernandez, S.E. Jones, K.M. Cadle, K.P. Smith, and M.F. Varela. (2009). Evidence for the transport of maltose by the sucrose permease, CscB, of Escherichia coli. J. Membr. Biol. 228: 79-88.

Perdomo-Ramirez, A., E. Cordoba-Lanus, C.J. Trujillo-Frias, C. Gonzalez-Navasa, E. Ramos-Trujillo, M.I. Luis-Yanes, V. Garcia-Nieto, F. Claverie-Martin, and. (2023). Pathogenic Variants of (URAT1) and (GLUT9) in Spanish Patients with Renal Hypouricemia: Founder Effect of Variant c.374C>T; p.(T125M). Int J Mol Sci 24:.

Pereira, C.A. and A.M. Silber. (2012). On the evolution of hexose transporters in kinetoplastid potozoans. PLoS One 7: e36303.

Perland, E., E. Lekholm, M.M. Eriksson, S. Bagchi, V. Arapi, and R. Fredriksson. (2016). The Putative SLC Transporters Mfsd5 and Mfsd11 Are Abundantly Expressed in the Mouse Brain and Have a Potential Role in Energy Homeostasis. PLoS One 11: e0156912.

Perland, E., S. Bagchi, A. Klaesson, and R. Fredriksson. (2017). Characteristics of 29 novel atypical solute carriers of major facilitator superfamily type: evolutionary conservation, predicted structure and neuronal co-expression. Open Biol 7:.

Perland, E., S.V. Hellsten, E. Lekholm, M.M. Eriksson, V. Arapi, and R. Fredriksson. (2016). The Novel Membrane-Bound Proteins MFSD1 and MFSD3 are Putative SLC Transporters Affected by Altered Nutrient Intake. J Mol Neurosci. [Epub: Ahead of Print]

Perland, E., S.V. Hellsten, N. Schweizer, V. Arapi, F. Rezayee, M. Bushra, and R. Fredriksson. (2017). Structural prediction of two novel human atypical SLC transporters, MFSD4A and MFSD9, and their neuroanatomical distribution in mice. PLoS One 12: e0186325.

Perry, J.L., N. Dembla-Rajpal, L.A. Hall, and J.B. Pritchard. (2006). A three-dimensional model of human organic anion transporter 1: aromatic amino acids required for substrate transport. J. Biol. Chem. 281: 38071-38079.

Persson, B.L., A. Berhe, U. Fristedt, P. Martinez, J. Pattison, J. Petersson, and R. Weinander. (1998). Phosphate permeases of Saccharomyces cerevisiae. Biochim. Biophys. Acta 1365: 23-30.

Persson, B.L., J. Petersson, U. Fristedt, R. Weinander, A. Berhe, and J. Pattison. (1999). Phosphate permeases of Saccharomyces cerevisiae: structure, function and regulation. Biochim. Biophys. Acta 1422: 255-272.

Philip, M., S.A. Funkhouser, E.Y. Chiu, S.R. Phelps, J.J. Delrow, J. Cox, P.J. Fink, and J.L. Abkowitz. (2015). Heme Exporter FLVCR Is Required for T Cell Development and Peripheral Survival. J Immunol 194: 1677-1685.

Pietrancosta, N., C. Anne, H. Prescher, R. Ruivo, C. Sagné, C. Debacker, H.O. Bertrand, R. Brossmer, F. Acher, and B. Gasnier. (2012). Successful prediction of substrate-binding pocket in SLC17 transporter sialin. J. Biol. Chem. 287: 11489-11497.

Pietrancosta, N., M. Djibo, S. Daumas, S. El Mestikawy, and J.D. Erickson. (2020). Molecular, Structural, Functional, and Pharmacological Sites for Vesicular Glutamate Transporter Regulation. Mol Neurobiol. [Epub: Ahead of Print]

Pimentel-Schmitt, E.F., K. Jahreis, M.P. Eddy, J. Amon, A. Burkovski, and F. Titgemeyer. (2009). Identification of a glucose permease from Mycobacterium smegmatis mc2 155. J. Mol. Microbiol. Biotechnol. 16: 169-175.

Pina, C., P. Goncalves, C. Prista, and M.C. Loureiro-Dias. (2004). Ffz1, a new transporter specific for fructose from Zygosaccharomyces bailii. Microbiology 150: 2429-2433.

Plourde-Owobi, L., S. Durner, J.L. Parrou, R. Wieczorke, G. Goma, and J. François. (1999). AGT1, encoding an α-glucoside transporter involved in uptake and intracellular accumulation of trehalose in Saccharomyces cerevisiae. J. Bacteriol. 181: 3830-3832.

Pochini, L., M. Scalise, M. Galluccio, and C. Indiveri. (2013). OCTN cation transporters in health and disease: role as drug targets and assay development. J Biomol Screen 18: 851-867.

Pochini, L., M. Scalise, S. Di Silvestre, S. Belviso, A. Pandolfi, A. Arduini, M. Bonomini, and C. Indiveri. (2015). Acetylcholine and acetylcarnitine transport in peritoneum: role of the SLC22A4 (OCTN1) transporter. Biochim. Biophys. Acta. [Epub: Ahead of Print]

Posavi, M., D. Gulisija, J.B. Munro, J.C. Silva, and C.E. Lee. (2020). Rapid evolution of genome-wide gene expression and plasticity during saline to freshwater invasions by the copepod Eurytemora affinis species complex. Mol Ecol. [Epub: Ahead of Print]

Prestin, K., S. Wolf, R. Feldtmann, J. Hussner, I. Geissler, C. Rimmbach, H.K. Kroemer, U. Zimmermann, and H.E. Meyer zu Schwabedissen. (2014). Transcriptional regulation of urate transportosome member SLC2A9 by nuclear receptor HNF4α. Am. J. Physiol. Renal Physiol 307: F1041-1051.

Price, D.R., H.S. Wilkinson, and J.A. Gatehouse. (2007). Functional expression and characterisation of a gut facilitative glucose transporter, NlHT1, from the phloem-feeding insect Nilaparvata lugens (rice brown planthopper). Insect Biochem Mol Biol 37: 1138-1148.

Psakis, G., M. Saidijam, K. Shibayama, J. Polaczek, K.E. Bettaney, J.M. Baldwin, S.A. Baldwin, R. Hope, L.O. Essen, R.C. Essenberg, and P.J. Henderson. (2009). The sodium-dependent D-glucose transport protein of Helicobacter pylori. Mol. Microbiol. 71: 391-403.

Puri, S. and K. Juvale. (2020). Monocarboxylate transporter 1 and 4 inhibitors as potential therapeutics for treating solid tumours: A review with structure-activity relationship insights. Eur J Med Chem 199: 112393. [Epub: Ahead of Print]

Qiao, Y., C. Li, X. Lu, H. Zong, and B. Zhuge. (2021). Identification of key residues for efficient glucose transport by the hexose transporter CgHxt4 in high sugar fermentation yeast Candida glycerinogenes. Appl. Microbiol. Biotechnol. [Epub: Ahead of Print]

Qin, L., X. Liu, Q. Sun, Z. Fan, D. Xia, G. Ding, H.L. Ong, D. Adams, W.A. Gahl, C. Zheng, S. Qi, L. Jin, C. Zhang, L. Gu, J. He, D. Deng, I.S. Ambudkar, and S. Wang. (2012). Sialin (SLC17A5) functions as a nitrate transporter in the plasma membrane. Proc. Natl. Acad. Sci. USA 109: 13434-13439.

Qin, Y., J. Wang, Q. Lv, and B. Han. (2023). Recent Progress in Research on Mitochondrion-Targeted Antifungal Drugs: a Review. Antimicrob. Agents Chemother. e0000323. [Epub: Ahead of Print]

Qiu, A., M. Jansen, A. Sakaris, S.H. Min, S. Chattopadhyay, E. Tsai, C. Sandoval, R. Zhao, M.H. Akabas, and I.D. Goldman. (2006). Identification of an intestinal folate transporter and the molecular basis for hereditary folate malabsorption. Cell 127: 917-928.

Quistgaard, E.M., C. Löw, P. Moberg, and P. Nordlund. (2013). Metal-mediated crystallization of the xylose transporter XylE from Escherichia coli in three different crystal forms. J Struct Biol 184: 375-378.

Radestock, S. and L.R. Forrest. (2011). The alternating-access mechanism of MFS transporters arises from inverted-topology repeats. J. Mol. Biol. 407: 698-715.

Rajamohan, G., V.B. Srinivasan, and W.A. Gebreyes. (2010). Molecular and functional characterization of a novel efflux pump, AmvA, mediating antimicrobial and disinfectant resistance in Acinetobacter baumannii. J Antimicrob Chemother 65: 1919-1925.

Ramìrez, S., R. Moreno, O. Zafra, P. Castàn, C. Vallès, and J. Berenguer. (2000). Two nitrate/nitrite transporters are encoded within the mobilizable plasmid for nitrate respiration of Thermus thermophilus HB8. J. Bacteriol. 182: 2179-2183.

Ramon-Garcia S., Martin C., Thompson CJ. and Ainsa JA. (2009). Role of the Mycobacterium tuberculosis P55 efflux pump in intrinsic drug resistance, oxidative stress responses, and growth. Antimicrob Agents Chemother. 53(9):3675-82.

Ramzan, R., M. Safiullah Virk, Z. Muhammad, A.M.M. Ahmed, X. Yuan, and F. Chen. (2019). Genetic Modification of Gene Stimulating the Putative Penicillin Production in M7 and Exhibiting the Sensitivity towards Precursor Amino Acids of Penicillin Pathway. Microorganisms 7:.

Rana, N., M.A. Aziz, R.A.T. Serya, D.S. Lasheen, N. Samir, F. Wuest, K.A.M. Abouzid, and F.G. West. (2023). A Fluorescence-Based Assay to Probe Inhibitory Effect of Fructose Mimics on GLUT5 Transport in Breast Cancer Cells. ACS Bio Med Chem Au 3: 51-61.

Rani, M., S. Raj, V. Dayaman, M. Kumar, M. Dua, and A.K. Johri. (2016). Functional Characterization of a Hexose Transporter from Root Endophyte Piriformospora indica. Front Microbiol 7: 1083.

Rappold, P.M., M. Cui, A.S. Chesser, J. Tibbett, J.C. Grima, L. Duan, N. Sen, J.A. Javitch, and K. Tieu. (2011). Paraquat neurotoxicity is mediated by the dopamine transporter and organic cation transporter-3. Proc. Natl. Acad. Sci. USA 108: 20766-20771.

Raschdorf, O., F.D. Müller, M. Pósfai, J.M. Plitzko, and D. Schüler. (2013). The magnetosome proteins MamX, MamZ and MamH are involved in redox control of magnetite biomineralization in Magnetospirillum gryphiswaldense. Mol. Microbiol. 89: 872-886.

Raven, L.M., C.A. Muir, C. Kessler Iglesias, N.K. Bart, K. Muthiah, E. Kotlyar, P. Macdonald, C.S. Hayward, A. Jabbour, and J.R. Greenfield. (2023). Sodium glucose co-transporter 2 inhibition with empagliflozin on metabolic, cardiac and renal outcomes in recent cardiac transplant recipients (EMPA-HTx): protocol for a randomised controlled trial. BMJ Open 13: e069641.

Ray, A., J. Wen, L. Yammine, J. Culver, I.S. Parida, J. Garren, L. Xue, K. Hales, Q. Xiang, M.J. Birnbaum, B.B. Zhang, M. Monetti, and T.E. McGraw. (2023). Regulated dynamic subcellular GLUT4 localization revealed by proximal proteome mapping in human muscle cells. J Cell Sci 136:.

Raymond-Bouchard I., Carroll CS., Nesbitt JR., Henry KA., Pinto LJ., Moinzadeh M., Scott JK. and Moore MM. (2012). Structural requirements for the activity of the MirB ferrisiderophore transporter of Aspergillus fumigatus. Eukaryot Cell. 11(11):1333-44.

Reddy, A., L.H.M. Bozi, O.K. Yaghi, E.L. Mills, H. Xiao, H.E. Nicholson, M. Paschini, J.A. Paulo, R. Garrity, D. Laznik-Bogoslavski, J.C.B. Ferreira, C.S. Carl, K.A. Sjøberg, J.F.P. Wojtaszewski, J.F. Jeppesen, B. Kiens, S.P. Gygi, E.A. Richter, D. Mathis, and E.T. Chouchani. (2020). pH-Gated Succinate Secretion Regulates Muscle Remodeling in Response to Exercise. Cell 183: 62-75.e17.

Redhu, A.K., A. Banerjee, A.H. Shah, A. Moreno, M.K. Rawal, R. Nair, P. Falson, and R. Prasad. (2018). Molecular Basis of Substrate Polyspecificity of the Candida albicans Mdr1p Multidrug/H Antiporter. J. Mol. Biol. 430: 682-694.

Reihl, P. and J. Stolz. (2005). The monocarboxylate transporter homolog Mch5p catalyzes riboflavin (vitamin B2) uptake in Saccharomyces cerevisiae. J. Biol. Chem. 280: 39809-39817.

Reinders, A., J.A. Panshyshyn, and J.M. Ward. (2005). Analysis of transport activity of Arabidopsis sugar alcohol permease homolog AtPLT5. J. Biol. Chem. 280: 1594-1602.

Remm, S., D. De Vecchis, J. Schöppe, C.A.J. Hutter, I. Gonda, M. Hohl, S. Newstead, L.V. Schäfer, and M.A. Seeger. (2023). Structural basis for triacylglyceride extraction from mycobacterial inner membrane by MFS transporter Rv1410. Nat Commun 14: 6449.

Remy, E., T.R. Cabrito, P. Baster, R.A. Batista, M.C. Teixeira, J. Friml, I. Sá-Correia, and P. Duque. (2013). A major facilitator superfamily transporter plays a dual role in polar auxin transport and drought stress tolerance in Arabidopsis. Plant Cell 25: 901-926.

Remy, E., T.R. Cabrito, R.A. Batista, M.A. Hussein, M.C. Teixeira, A. Athanasiadis, I. Sá-Correia, and P. Duque. (2014). Intron retention in the 5''UTR of the novel ZIF2 transporter enhances translation to promote zinc tolerance in arabidopsis. PLoS Genet 10: e1004375.

Ren F., Zhao CZ., Liu CS., Huang KL., Guo QQ., Chang LL., Xiong H. and Li XB. (2014). A Brassica napus PHT1 phosphate transporter, BnPht1;4, promotes phosphate uptake and affects roots architecture of transgenic Arabidopsis. Plant Mol Biol. 86(6):595-607.

Reynes, J.P., T. Calmels, D. Drocourt, and G. Tiraby. (1988). Cloning, expression in Escherichia coli and nucleotide sequence of a tetracycline-resistance gene from Streptomyces rimosus. J. Gen. Microbiol. 134: 585-598.

Ricard-Blum, S. and J.R. Couchman. (2023). Conformations, interactions and functions of intrinsically disordered syndecans. Biochem Soc Trans 51: 1083-1096.

Rizwan, A.N., W. Krick, G. Burckhardt. (2007). The chloride dependence of the human organic anion transporter 1 (hOAT1) is blunted by mutation of a single amino acid. J. Biol. Chem. 282: 13402-13409.

Roca, I., S. Marti, P. Espinal, P. Martínez, I. Gibert, and J. Vila. (2009). CraA, a major facilitator superfamily efflux pump associated with chloramphenicol resistance in Acinetobacter baumannii. Antimicrob. Agents Chemother. 53: 4013-4014.

Rodionov, D.A., A.G. Vitreschak, A.A. Mironov, and M.S. Gelfand. (2002). Comparative genomics of thiamin biosynthesis in procaryotes. New genes and regulatory mechanisms. J. Biol. Chem. 277: 48949-48959.

Rodionov, D.A., C. Yang, X. Li, I.A. Rodionova, Y. Wang, A.Y. Obraztsova, O.P. Zagnitko, R. Overbeek, M.F. Romine, S. Reed, J.K. Fredrickson, K.H. Nealson, and A.L. Osterman. (2010). Genomic encyclopedia of sugar utilization pathways in the Shewanella genus. BMC Genomics 11: 494.

Rodionov, D.A., P. Hebbeln, A. Eudes, J. ter Beek, I.A. Rodionova, G.B. Erkens, D.J. Slotboom, M.S. Gelfand, A.L. Osterman, A.D. Hanson, and T. Eitinger. (2009). A novel class of modular transporters for vitamins in prokaryotes. J. Bacteriol. 191: 42-51.

Rodionov, D.A., X. Li, I.A. Rodionova, C. Yang, L. Sorci, E. Dervyn, D. Martynowski, H. Zhang, M.S. Gelfand, and A.L. Osterman. (2008). Transcriptional regulation of NAD metabolism in bacteria: genomic reconstruction of NiaR (YrxA) regulon. Nucleic Acids Res 36: 2032-2046.

Rodionova, I.A., Y. Gao, A. Sastry, Y. Hefner, H.G. Lim, D.A. Rodionov, M.H. Saier, Jr, and B.O. Palsson. (2021). Identification of a transcription factor, PunR, that regulates the purine and purine nucleoside transporter punC in E. coli. Commun Biol 4: 991.

Rodrigues, L., J. Ramos, I. Couto, L. Amaral, and M. Viveiros. (2011). Ethidium bromide transport across Mycobacterium smegmatis cell-wall: correlation with antibiotic resistance. BMC Microbiol 11: 35.

Rodriguez-Contreras, D., H. Aslan, X. Feng, K. Tran, P.A. Yates, S. Kamhawi, and S.M. Landfear. (2015). Regulation and biological function of a flagellar glucose transporter in Leishmania mexicana: a potential glucose sensor. FASEB J. 29: 11-24.

Rolland, S., M. Hnatova, M. Lemaire, J. Leal-Sanchez, and M. Wésolowski-Louvel. (2006). Connection between the Rag4 glucose sensor and the KlRgt1 repressor in Kluyveromyces lactis. Genetics 174: 617-626.

Roohparvar, R., M.A. De Waard, G.H. Kema, and L.H. Zwiers. (2007). MgMfs1, a major facilitator superfamily transporter from the fungal wheat pathogen Mycosphaerella graminicola, is a strong protectant against natural toxic compounds and fungicides. Fungal Genet Biol 44: 378-388.

Ropka-Molik, K., M. Stefaniuk-Szmukier, T. Szmatoła, K. Piórkowska, and M. Bugno-Poniewierska. (2019). The use of the SLC16A1 gene as a potential marker to predict race performance in Arabian horses. BMC Genet 20: 73.

Roshanbin, S., F.A. Lindberg, E. Lekholm, M.M. Eriksson, E. Perland, J. Åhlund, A. Raine, and R. Fredriksson. (2016). Histological characterization of orphan transporter MCT14 (SLC16A14) shows abundant expression in mouse CNS and kidney. BMC Neurosci 17: 43.

Rottmann, T., W. Zierer, C. Subert, N. Sauer, and R. Stadler. (2016). STP10 encodes a high-affinity monosaccharide transporter and is induced under low-glucose conditions in pollen tubes of Arabidopsis. J Exp Bot. [Epub: Ahead of Print]

Rubio, L., J. Díaz-García, V. Amorim-Silva, A.P. Macho, M.A. Botella, and J.A. Fernández. (2019). Molecular Characterization of , the Putative Sodium Dependent High-Affinity Nitrate Transporter of L. Int J Mol Sci 20:.

Ruiz-Pavón, L., P.M. Karlsson, J. Carlsson, D. Samyn, B. Persson, B.L. Persson, and C. Spetea. (2010). Functionally important amino acids in the Arabidopsis thylakoid phosphate transporter: homology modeling and site-directed mutagenesis. Biochemistry 49: 6430-6439.

Ruscitto, A., K. Honma, V.M. Veeramachineni, K. Nishikawa, G.P. Stafford, and A. Sharma. (2017). Regulation and Molecular Basis of Environmental Muropeptide Uptake and Utilization in Fastidious Oral Anaerobe. Front Microbiol 8: 648.

Ryu, N., B. Sagong, H.J. Park, M.A. Kim, K.Y. Lee, J.Y. Choi, and U.K. Kim. (2016). Screening of the SLC17A8 gene as a causative factor for autosomal dominant non-syndromic hearing loss in Koreans. BMC Med Genet 17: 6.

Sa-Nogueira I. and Ramos S.S. (1997). Cloning, functional analysis, and transcriptional regulation of the Bacillus subtilis araE gene involved in L-arabinose utilization. J. of Bacteriol. 179:7705-7711.

Sachs, M., A.R. Quijada-Rodriguez, S. Hans, and D. Weihrauch. (2022). Characterization of two novel ammonia transporters, HIAT1α and HIAT1β, in the American Horseshoe Crab, Limulus polyphemus. Comp Biochem Physiol A Mol Integr Physiol 278: 111365. [Epub: Ahead of Print]

Sager, G., N. Smaglyukova, and O.M. Fuskevaag. (2018). The role of OAT2 (SLC22A7) in the cyclic nucleotide biokinetics of human erythrocytes. J Cell Physiol 233: 5972-5980.

Sagor, G.H., T. Berberich, S. Kojima, M. Niitsu, and T. Kusano. (2016). Spermine modulates the expression of two probable polyamine transporter genes and determines growth responses to cadaverine in Arabidopsis. Plant Cell Rep 35: 1247-1257.

Saha, M., A.K. Pragasam, S. Kumari, J. Verma, B. Das, and R.K. Bhadra. (2024). Genomic and functional insights into antibiotic resistance genes and linked with the SXT element of non-O1/non-O139. Microbiology (Reading) 170:.

Saha, P., S. Sikdar, G. Krishnamoorthy, H.I. Zgurskaya, and V.V. Rybenkov. (2020). Drug Permeation against Efflux by Two Transporters. ACS Infect Dis 6: 747-758.

Said, H.M., K. Van Voorhis, F.K. Ghishan, N. Abumurad, W. Nylander, and R. Redha. (1989). Transport characteristics of glutamine in human intestinal brush-border membrane vesicles. Am. J. Physiol. 256: G240-245.

Saier, M.H., Jr, D.L. Wentzel, B.U. Feucht, and J.J. Judice. (1975). A transport system for phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate in Salmonella typhimurium. J. Biol. Chem. 250: 5089-5096.

Saitoh H., Hirabuchi A., Fujisawa S., Mitsuoka C., Terauchi R. and Takano Y. (2014). MoST1 encoding a hexose transporter-like protein is involved in both conidiation and mycelial melanization of Magnaporthe oryzae. FEMS Microbiol Lett. 352(1):104-13.

Sakamoto, T., K. Inoue-Sakamoto, and D.A. Bryant. (1999). A novel nitrate/nitrite permease in the marine cyanobacterium Synechococcus sp. strain PCC 7002. J. Bacteriol. 181: 7363-7372.

Salcedo-Sora, J.E., S. Jindal, S. O''Hagan, and D.B. Kell. (2021). A palette of fluorophores that are differentially accumulated by wild-type and mutant strains of : surrogate ligands for profiling bacterial membrane transporters. Microbiology (Reading) 167:.

Salveridou, E., S. Mayerl, S.M. Sundaram, B. Markova, and H. Heuer. (2020). Tissue-Specific Function of Thyroid Hormone Transporters: New Insights from Mouse Models. Exp Clin Endocrinol Diabetes 128: 423-427.

Samodelov, S.L., G.A. Kullak-Ublick, Z. Gai, and M. Visentin. (2020). Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology. Int J Mol Sci 21:.

Sandoval, G.M., J.S. Duerr, J. Hodgkin, J.B. Rand, and G. Ruvkun. (2006). A genetic interaction between the vesicular acetylcholine transporter VAChT/UNC-17 and synaptobrevin/SNB-1 in C. elegans. Nat Neurosci 9: 599-601.

Sano, R., Y. Shinozaki, and T. Ohta. (2020). Sodium-glucose cotransporters: Functional properties and pharmaceutical potential. J Diabetes Investig. [Epub: Ahead of Print]

Santiviago, C.A., J.A. Fuentes, S.M. Bueno, A.N. Trombert, A.A. Hildago, L.T. Socias, P. Youderian, and G.C. Mora. (2002). The Salmonella entrica sv. Typhimurium smvA, yddG and ompD (porin) genes are required for the efficient efflux of methyl viologen. Mol. Microbiol. 46: 687-698.

Sanyal, S. and M. Ramaswami. (2002). Spinsters, synaptic defects, and amaurotic idiocy. Neuron 36: 335-338.

Sapunaric, F.M. and S.B. Levy. (2005). Substitutions in the interdomain loop of the Tn10 TetA efflux transporter alter tetracycline resistance and substrate specificity. Microbiology 151: 2315-2322.

Sardar, D., Y.T. Cheng, J. Woo, D.J. Choi, Z.F. Lee, W. Kwon, H.C. Chen, B. Lozzi, A. Cervantes, K. Rajendran, T.W. Huang, A. Jain, B.R. Arenkiel, I. Maze, and B. Deneen. (2023). Induction of astrocytic Slc22a3 regulates sensory processing through histone serotonylation. Science 380: eade0027.

Sargiacomo, M., M. Valtieri, M. Gabbianelli, E. Pelosi, U. Testa, A. Camagna, and C. Peschle. (1991). Pure human hematopoietic progenitors: direct inhibitory effect of transforming growth factors-beta 1 and -beta 2. Ann. N.Y. Acad. Sci. 628: 84-91.

Sasa, K., K. Yoshimura, A. Yamada, D. Suzuki, Y. Miyamoto, H. Imai, K. Nagayama, K. Maki, M. Yamamoto, and R. Kamijo. (2018). Monocarboxylate transporter-1 promotes osteoblast differentiation via suppression of p53, a negative regulator of osteoblast differentiation. Sci Rep 8: 10579.

Sasaki, M. and Y. Kurusu. (2004). Analysis of spontaneous base substitutions generated in mutator strains of Bacillus subtilis. FEMS Microbiol. Lett. 234: 37-42.

Sato, M. and M. Mueckler. (1999). A conserved amino acid motif (R-X-G-R-R) in the Glut1 glucose transporter is an important determinant of membrane topology. J. Biol. Chem. 274: 24721-24725.

Sauer, J.-D., Bachman, M.A., and Swanson, M.S. (2005). The phagosomal transporter A couples threonine acquisition to differentiation and replication of Legionella pneumophila in macrophages. Proc. Natl. Acad. Sci. USA 102: 9924-9929.

Savalas, L.R., B. Gasnier, M. Damme, T. Lübke, C. Wrocklage, C. Debacker, A. Jézégou, T. Reinheckel, A. Hasilik, P. Saftig, and B. Schröder. (2011). Disrupted in renal carcinoma 2 (DIRC2), a novel transporter of the lysosomal membrane, is proteolytically processed by cathepsin L. Biochem. J. 439: 113-128.

Sawada, K., N. Echigo, N. Juge, T. Miyaji, M. Otsuka, H. Omote, A. Yamamoto, and Y. Moriyama. (2008). Identification of a vesicular nucleotide transporter. Proc. Natl. Acad. Sci. USA. 105: 5683-5686.

Schaedler TA. and van Veen HW. (2010). A flexible cation binding site in the multidrug major facilitator superfamily transporter LmrP is associated with variable proton coupling. FASEB J. 24(10):3653-61.

Scharenberg, S.G., W. Dong, A. Ghoochani, K. Nyame, R. Levin-Konigsberg, A.R. Krishnan, E.S. Rawat, K. Spees, M.C. Bassik, and M. Abu-Remaileh. (2023). An SPNS1-dependent lysosomal lipid transport pathway that enables cell survival under choline limitation. Sci Adv 9: eadf8966.

Scharff-Poulsen, P., H. Moriya, and M. Johnston. (2018). Genetic Analysis of Signal Generation by the Rgt2 Glucose Sensor of. G3 (Bethesda). [Epub: Ahead of Print]

Schaub, R.E. and J.P. Dillard. (2019). The Pathogenic Neisseria Use a Streamlined Set of Peptidoglycan Degradation Proteins for Peptidoglycan Remodeling, Recycling, and Toxic Fragment Release. Front Microbiol 10: 73.

Scheepers, A., S. Schmidt, A. Manolescu, C.I. Cheeseman, A. Bell, C. Zahn, H.G. Joost, and A. Schürmann. (2005). Characterization of the human SLC2A11 (GLUT11) gene: alternative promoter usage, function, expression, and subcellular distribution of three isoforms, and lack of mouse orthologue. Mol. Membr. Biol. 22: 339-351.

Schilling, S. and C. Oesterhelt. (2007). Structurally reduced monosaccharide transporters in an evolutionarily conserved red alga. Biochem. J. 406: 325-331.

Schlessinger, A., N. Zatorski, K. Hutchinson, and C. Colas. (2023). Targeting SLC transporters: small molecules as modulators and therapeutic opportunities. Trends. Biochem. Sci. [Epub: Ahead of Print]

Schmidl, S., S.A. Tamayo Rojas, C.V. Iancu, J.Y. Choe, and M. Oreb. (2020). Functional Expression of the Human Glucose Transporters GLUT2 and GLUT3 in Yeast Offers Novel Screening Systems for GLUT-Targeting Drugs. Front Mol Biosci 7: 598419.

Schmitt, B.M. and H. Koepsell. (2005). Alkali cation binding and permeation in the rat organic cation transporter rOCT2. J. Biol. Chem. 280: 24481-24490.

Schneider, S., A. Schneidereit, K.R. Konrad, M.R. Hajirezaei, M. Gramann, R. Hedrich, and N. Sauer. (2006). Arabidopsis INOSITOL TRANSPORTER4 mediates high-affinity H+ symport of myoinositol across the plasma membrane. Plant Physiol. 141:565-577.

Schneider, S., A. Schneidereit, P. Udvardi, U. Hammes, M. Gramann, P. Dietrich, and N. Sauer. (2007). Arabidopsis INOSITOL TRANSPORTER2 Mediates H+-Symport of Different Inositol Epimers and Derivatives across the Plasma Membrane. Plant Physiol. 145: 1395-1407.

Schneider, S., D. Beyhl, R. Hedrich, and N. Sauer. (2008). Functional and Physiological Characterization of Arabidopsis INOSITOL TRANSPORTER1, a Novel Tonoplast-Localized Transporter for myo-Inositol. Plant Cell 20: 1073-1087.

Schneidereit, A., J. Scholz-Starke, N. Sauer, and M. Büttner. (2005). AtSTP11, a pollen tube-specific monosaccharide transporter in Arabidopsis. Planta.221: 48-55.

Scholz-Starke J., M. Büttner, and N. Sauer. (2003). AtSTP6, a new pollen-specific H+-monosaccharide symporter from Arabidopsis. Plant Physiol. 131:70-77.

Schouler, C., A. Taki, I. Chouikha, M. Moulin-Schouleur, and P. Gilot. (2009). A genomic island of an extraintestinal pathogenic Escherichia coli Strain enables the metabolism of fructooligosaccharides, which improves intestinal colonization. J. Bacteriol. 191: 388-393.

Schubbe, S., M. Kube, A. Scheffel, C. Wawer, U. Heyen, A. Meyerdierks, M.H. Madkour, F. Mayer, R. Reinhardt, and D. Schüler. (2003). Characterization of a spontaneous nonmagnetic mutant of Magnetospirillum gryphiswaldense reveals a large deletion comprising a putative magnetosome island. J. Bacteriol. 185: 5779–5790.

Schuldiner, S., A. Shirvan, and M. Linial. (1995). Vesicular neurotransmitter transporters: from bacteria to humans. Physiol. Rev. 75: 369-392.

Schulz, A., D. Beyhl, I. Marten, A. Wormit, E. Neuhaus, G. Poschet, M. Büttner, S. Schneider, N. Sauer, and R. Hedrich. (2011). Proton-driven sucrose symport and antiport are provided by the vacuolar transporters SUC4 and TMT1/2. Plant J. 68: 129-136.

Schussler, A., H. Martin, D. Cohen, M. Fitz, and D. Wipf. (2006). Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi. Nature 444: 933-936.

Schweizer U. and Kohrle J. (2013). Function of thyroid hormone transporters in the central nervous system. Biochim Biophys Acta. 1830(7):3965-73.

Schwöppe, C., H.H. Winkler, and H.E. Neuhaus. (2002). Properties of the glucose-6-phosphate transporter from Chlamydia pneumoniae (HPTcp) and the glucose-6-phosphate sensor from Escherichia coli (UhpC). J. Bacteriol. 184: 2108-2115.

Scisciola, L., F. Taktaz, R.A. Fontanella, A. Pesapane, Surina, V. Cataldo, P. Ghosh, M. Franzese, A. Puocci, P. Paolisso, C. Rafaniello, R. Marfella, M.R. Rizzo, E. Barbato, M. Vanderheyden, and M. Barbieri. (2023). Targeting high glucose-induced epigenetic modifications at cardiac level: the role of SGLT2 and SGLT2 inhibitors. Cardiovasc Diabetol 22: 24.

Sealover, N.R., B. Felts, C.P. Kuntz, R.E. Jarrard, G.H. Hockerman, E.L. Barker, and L.K. Henry. (2016). The external gate of the human and Drosophila serotonin transporters requires a basic/acidic amino acid pair for 3,4-methylenedioxymethamphetamine (MDMA) translocation and the induction of substrate efflux. Biochem Pharmacol 120: 46-55.

Seatter, M.J., S.A. De la Rue, L.M. Porter, and G.W. Gould. (1998). QLS motif in transmembrane helix VII of the glucose transporter family interacts with the C-1 position of D-glucose and is involved in substrate selection at the exofacial binding site. Biochemistry 37: 1322-1326.

Seeger, C., C. Poulsen, and G. Dandanell. (1995). Identification and characterization of genes (xapA, xapB, and xapR) involved in xanthosine catabolism in Escherichia coli. J. Bacteriol. 177: 5506-5516.

Sekine, T., S.H. Cha, M. Tsuda, N. Apiwattanakul, N. Nakajima, Y. Kanai, and H. Endou. (1998). Identification of multispecific organic anion transporter 2 expressed predominantly in the liver. FEBS Lett. 429: 179-182.

Seol, W. and A.J. Shatkin. (1992). Escherichia coli α-ketoglutarate permease is a constitutively expressed proton symporter. J. Biol. Chem. 267: 6409-6413.

Seol, W. and A.J. Shatkin. (1992). Site-directed mutants of Escherichia coli α-ketoglutarate permease (KgtP). Biochemistry 31: 3550-3554.

Serdiuk, T., S.A. Mari, and D.J. Müller. (2017). Pull-and-Paste of Single Transmembrane Proteins. Nano Lett. [Epub: Ahead of Print]

Serrano-Saiz, E., M.C. Vogt, S. Levy, Y. Wang, K.K. Kaczmarczyk, X. Mei, G. Bai, A. Singson, B.D. Grant, and O. Hobert. (2019). SLC17A6/7/8 Vesicular Glutamate Transporter Homologs in Nematodes. Genetics. [Epub: Ahead of Print]

Serrano-Saiz, E., R.J. Poole, T. Felton, F. Zhang, E.D. De La Cruz, and O. Hobert. (2013). Modular control of glutamatergic neuronal identity in C. elegans by distinct homeodomain proteins. Cell 155: 659-673.

Shaheen, A., F. Ismat, M. Iqbal, A. Haque, Z. Ul-Haq, O. Mirza, R. De Zorzi, T. Walz, and M. Rahman. (2021). Characterization of the multidrug efflux transporter styMdtM from Salmonella enterica serovar Typhi. Proteins 89: 1193-1204.

Shaji, D. (2021). Identification of Inhibitors Based on Molecular Docking: Thyroid Hormone Transmembrane Transporter MCT8 as a Target. Curr Drug Discov Technol 18: 105-112.

Sharifi, A., M. Kousi, C. Sagné, G.C. Bellenchi, L. Morel, M. Darmon, H. Hulková, R. Ruivo, C. Debacker, S. El Mestikawy, M. Elleder, A.E. Lehesjoki, A. Jalanko, B. Gasnier, and A. Kyttälä. (2010). Expression and lysosomal targeting of CLN7, a major facilitator superfamily transporter associated with variant late-infantile neuronal ceroid lipofuscinosis. Hum Mol Genet 19: 4497-4514.

Sharlin, D.S., L. Ng, F. Verrey, T.J. Visser, Y. Liu, R.T. Olszewski, M. Hoa, H. Heuer, and D. Forrest. (2018). Deafness and loss of cochlear hair cells in the absence of thyroid hormone transporters Slc16a2 (Mct8) and Slc16a10 (Mct10). Sci Rep 8: 4403.

Sharma, S., A. Banerjee, A. Moreno, A.K. Redhu, P. Falson, and R. Prasad. (2022). Spontaneous Suppressors against Debilitating Transmembrane Mutants of Mdr1 Disclose Novel Interdomain Communication via Signature Motifs of the Major Facilitator Superfamily. J Fungi (Basel) 8:.

Sharma, V., C.E. Noriega, and J.J. Rowe. (2006). Involvement of NarK1 and NarK2 proteins in transport of nitrate and nitrite in the denitrifying bacterium Pseudomonas aeruginosa PAO1. Appl. Environ. Microbiol. 72: 695-701.

Shayeghi, M., G.O. Latunde-Dada, J.S. Oakhill, A.H. Laftah, K. Takeuchi, N. Halliday, Y. Khan, A. Warley, F.E. McCann, R.C. Hider, D.M. Frazer, G.J. Anderson, C.D. Vulpe, R.J. Simpson, and A.T. McKie. (2005). Identification of an intestinal heme transporter. Cell 122: 789-801.

Sheremet, A.S., S.V. Gronskiy, R.A. Akhmadyshin, A.E. Novikova, V.A. Livshits, R.S. Shakulov, and N.P. Zakataeva. (2011). Enhancement of extracellular purine nucleoside accumulation by Bacillus strains through genetic modifications of genes involved in nucleoside export. J Ind Microbiol Biotechnol 38: 65-70.

Shi, K., C. Li, C. Rensing, X. Dai, X. Fan, and G. Wang. (2018). A novel efflux transporter, ArsK, is responsible for bacterial resistance to arsenite, antimonite, trivalent roxarsone and methylarsenite. Appl. Environ. Microbiol. [Epub: Ahead of Print]

Shim, M.S., J.Y. Kim, K.H. Lee, H.K. Jung, B.A. Carlson, X.M. Xu, D.L. Hatfield, and B.J. Lee. (2011). l(2)01810 is a novel type of glutamate transporter that is responsible for megamitochondrial formation. Biochem. J. 439: 277-286.

Shimazu, M., T. Sekito, K. Akiyama, Y. Ohsumi, and Y. Kakinuma. (2005). A family of basic amino acid transporters of the vacuolar membrane from Saccharomyces cerevisiae. J. Biol. Chem. 280: 4851-4857.

Shin DS., Zhao R., Fiser A. and Goldman DI. (2012). Functional roles of the A335 and G338 residues of the proton-coupled folate transporter (PCFT-SLC46A1) mutated in hereditary folate malabsorption. Am J Physiol Cell Physiol. 303(8):C834-42.

Shin, D.S., R. Zhao, E.H. Yap, A. Fiser, and I.D. Goldman. (2012). A P425R mutation of the proton-coupled folate transporter causing hereditary folate malabsorption produces a highly selective alteration in folate binding. Am. J. Physiol. Cell Physiol. 302: C1405-1412.

Shin, D.S., S.H. Min, L. Russell, R. Zhao, A. Fiser, and I.D. Goldman. (2010). Functional roles of aspartate residues of the proton-coupled folate transporter (PCFT-SLC46A1); a D156Y mutation causing hereditary folate malabsorption. Blood 116: 5162-5169.

Shin, H.J., N. Anzai, A. Enomoto, X. He, do K. Kim, H. Endou, and Y. Kanai. (2007). Novel liver-specific organic anion transporter OAT7 that operates the exchange of sulfate conjugates for short chain fatty acid butyrate. Hepatology. 45: 1046-1055.

Shinnick, S.G., S.A. Perez, and M.F. Varela. (2003). Altered substrate selection of the melibiose transporter (MelY) of Enterobacter cloacae involving point mutations in Leu-88, Leu-91, and Ala-182 that confer enhanced maltose transport. J. Bacteriol. 185: 3672-3677.

Shiraya, K., T. Hirata, R. Hatano, S. Nagamori, P. Wiriyasermkul, P. Jutabha, M. Matsubara, S. Muto, H. Tanaka, S. Asano, N. Anzai, H. Endou, A. Yamada, H. Sakurai, and Y. Kanai. (2010). A novel transporter of SLC22 family specifically transports prostaglandins and co-localizes with 15-hydroxyprostaglandin dehydrogenase in renal proximal tubules. J. Biol. Chem. 285: 22141-22151.

Shishmarev, D., C.Q. Fontenelle, I. Kuprov, B. Linclau, and P.W. Kuchel. (2018). Transmembrane Exchange of Fluorosugars: Characterization of Red Cell GLUT1 Kinetics Using F NMR. Biophys. J. 115: 1906-1919.

Šikić, K., T. M A Peters, E. Marušić, I. Čulo Čagalj, D. Petković Ramadža, T. Žigman, K. Fumić, E. Fernandez, K. Gevaert, &.#.3.8.1.;. Debeljak, R. A Wevers, and I. Barić. (2022). Abnormal concentrations of acetylated amino acids in cerebrospinal fluid in acetyl-CoA transporter deficiency. J Inherit Metab Dis. [Epub: Ahead of Print]

Sim, S.Y., E.J. Hong, Y. Kim, and H.S. Lee. (2014). Analysis of cepA encoding an efflux pump-like protein in Corynebacterium glutamicum. J Microbiol 52: 278-283.

Singh, A.K. and R. Singh. (2020). Cardiovascular outcomes with SGLT-2 inhibitors and GLP-1 receptor agonist in Asians with type 2 diabetes: A systematic review and meta-analysis of cardiovascular outcome trials. Diabetes Metab Syndr 14: 715-722. [Epub: Ahead of Print]

Singh, G. and Y. Akhter. (2021). Molecular insights into the differential efflux mechanism of Rv1634 protein, a multidrug transporter of major facilitator superfamily in Mycobacterium tuberculosis. Proteins. [Epub: Ahead of Print]

Sionov, R.V., S. Banerjee, S. Bogomolov, R. Smoum, R. Mechoulam, and D. Steinberg. (2022). Targeting the Achilles'' Heel of Multidrug-Resistant by the Endocannabinoid Anandamide. Int J Mol Sci 23:.

Siskind, L.J., L. Feinstein, T. Yu, J.S. Davis, D. Jones, J. Choi, J.E. Zuckerman, W. Tan, R.B. Hill, J.M. Hardwick, and M. Colombini. (2008). Anti-apoptotic Bcl-2 Family proteins disassemble ceramide channels. J. Biol. Chem. 283: 6622-6630.

Skelly, P.J., J.W. Kim, J. Cunningham, and C.B. Shoemaker. (1994). Cloning, characterization, and functional expression of cDNAs encoding glucose transporter proteins from the human parasite Schistosoma mansoni. J. Biol. Chem. 269: 4247-4253.

Slavetinsky, C.J., A. Peschel, and C.M. Ernst. (2012). Alanyl-phosphatidylglycerol and lysyl-phosphatidylglycerol are translocated by the same MprF flippases and have similar capacities to protect against the antibiotic daptomycin in Staphylococcus aureus. Antimicrob. Agents Chemother. 56: 3492-3497.

Sloothaak, J., M. Schilders, P.J. Schaap, and L.H. de Graaff. (2014). Overexpression of the Aspergillus niger GatA transporter leads to preferential use of D-galacturonic acid over D-xylose. AMB Express 4: 66.

Smirnova, I., V. Kasho, and H.R. Kaback. (2011). Lactose permease and the alternating access mechanism. Biochemistry 50: 9684-9693.

Smirnova, I., V. Kasho, J. Sugihara, and H.R. Kaback. (2011). Opening the periplasmic cavity in lactose permease is the limiting step for sugar binding. Proc. Natl. Acad. Sci. USA 108: 15147-15151.

Smit, A., S.G. Moses, I.S. Pretorius, and R.R. Cordero Otero. (2008). The Thr505 and Ser557 residues of the AGT1-encoded α- glucoside transporter are critical for maltotriose transport in Saccharomyces cerevisiae. J. Appl. Microbiol. 104: 1103-1111.

Smith, D.J., J. Park, J.M. Tiedje, and W.W. Mohn. (2007). A large gene cluster in Burkholderia xenovorans encoding abietane diterpenoid catabolism. J. Bacteriol. 189: 6195-6204.

Smith, K.P., S. Kumar, and M.F. Varela. (2009). Identification, cloning, and functional characterization of EmrD-3, a putative multidrug efflux pump of the major facilitator superfamily from Vibrio cholerae O395. Arch. Microbiol. 191: 903-911.

Soares-Silva, I., J. Sá-Pessoa, V. Myrianthopoulos, E. Mikros, M. Casal, and G. Diallinas. (2011). A substrate translocation trajectory in a cytoplasm-facing topological model of the monocarboxylate/H⁺ symporter Jen1p. Mol. Microbiol. 81: 805-817.

Soares-Silva, I., S. Paiva, P. Kötter, K.D. Entian, and M. Casal. (2013). The disruption of JEN1 from Candida albicans impairs the transport of lactate. Mol. Membr. Biol. 21: 403-411.

Son, H.Y., S.W. Sohn, S.H. Im, H.J. Kim, M.K. Lee, B. Gombojav, H.S. Kwon, D.S. Park, H.L. Kim, K.U. Min, J. Sung, J.S. Seo, and J.I. Kim. (2015). Family-Based Association Study of Pulmonary Function in a Population in Northeast Asia. PLoS One 10: e0139716.

Soo, V.W., P. Hanson-Manful, and W.M. Patrick. (2011). Artificial gene amplification reveals an abundance of promiscuous resistance determinants in Escherichia coli. Proc. Natl. Acad. Sci. USA 108: 1484-1489.

Srinivas, S.R., P.D. Prasad, N.S. Umapathy, V. Ganapathy, and P.S. Shekhawat. (2007). Transport of butyryl-L-carnitine, a potential prodrug, via the carnitine transporter OCTN2 and the amino acid transporter ATB0,+. Am. J. Physiol. Gastrointest Liver Physiol 293: G1046-1053.

Stadler, R., M. Büttner, P. Ache, R. Hedrich, N. Ivashikina, M. Melzer, S.M. Shearson, S.M. Smith, and N. Sauer. (2003). Diurnal and light-regulated expression of AtSTP1 in guard cells of Arabidopsis. Plant Physiol. 133: 528-537.

Stasyk, O.G., M.M. Maidan, O.V. Stasyk, P. Van Dijck, J.M. Thevelein, and A.A. Sibirny. (2008). Identification of hexose transporter-like sensor HXS1 and functional hexose transporter HXT1 in the methylotrophic yeast Hansenula polymorpha. Eukaryot. Cell. 7(4): 735-746.

Stasyk, O.V., O.G. Stasyk, J. Komduur, M. Veenhuis, J.M. Cregg, and A.A. Sibirny. (2004). A hexose transporter homologue controls glucose repression in the methylotrophic yeast Hansenula polymorpha. J. Biol. Chem. 279: 8116-8125.

Staub, J.M., L. Brand, M. Tran, Y. Kong, and S.G. Rogers. (2012). Bacterial glyphosate resistance conferred by overexpression of an E. coli membrane efflux transporter. J Ind Microbiol Biotechnol 39: 641-647.

Staubitz, P., H. Neumann, T. Schneider, I. Wiedemann, and A. Peschel. (2004). MprF-mediated biosynthesis of lysylphosphatidylglycerol, an important determinant in staphylococcal defensin resistance. FEMS Microbiol. Lett. 231: 67-71.

Stolz, J. (2003). Isolation and characterization of the plasma membrane biotin transporter from Schizosaccharomyces pombe. Yeast. 20: 221-231.

Stolz, J., H.J. Wöhrmann, and C. Vogl. (2005). Amiloride uptake and toxicity in fission yeast are caused by the pyridoxine transporter encoded by bsu1+ (car1+). Eukaryot. Cell. 4: 319-326.

Stolz, J., T. Caspari, A.M. Carr, N. Sauer. (2004). Cell division defects of Schizosaccharomyces pombe liz1- mutants are caused by defects in pantothenate uptake. Euk. Cell 3: 406-412.

Stolz, J., U. Hoja, S, Meier, N. Sauer, and E. Schweizer. (2000). Identification of the plasma membrane H+-biotin symporter of Saccharomyces cerevisiae by rescue of a fatty acid-auxotrophic mutant. J. Biol. Chem. 274: 18741-18746.

Stout, K.A., A.R. Dunn, C. Hoffman, and G.W. Miller. (2019). The Synaptic Vesicle Glycoprotein 2: Structure, Function, and Disease Relevance. ACS Chem Neurosci 10: 3927-3938.

Strohm, A.K., L.M. Vaughn, and P.H. Masson. (2015). Natural variation in the expression of ORGANIC CATION TRANSPORTER 1 affects root length responses to cadaverine in Arabidopsis. J Exp Bot 66: 853-862.

Stroobants, K., J.R. Kumita, N.J. Harris, D.Y. Chirgadze, C.M. Dobson, P.J. Booth, and M. Vendruscolo. (2017). Amyloid-like Fibrils from an α-Helical Transmembrane Protein. Biochemistry 56: 3225-3233.

Sturm, A., V. Gorboulev, D. Gorbunov, T. Keller, C. Volk, B.M. Schmitt, P. Schlachtbauer, G. Ciarimboli, and H. Koepsell. (2007). Identification of cysteines in rat organic cation transporters rOCT1 (C322, C451) and rOCT2 (C451) critical for transport activity and substrate affinity. Am. J. Physiol. Renal Physiol 293: F767-779.

Su X. and Tsang JS. (2013). Existence of a robust haloacid transport system in a Burkholderia species bacterium. Biochim Biophys Acta. 1828(2):187-92.

Su, X., R. Li, K.F. Kong, and J.S. Tsang. (2016). Transport of haloacids across biological membranes. Biochim. Biophys. Acta. 1858: 3061-3070.

Subramanian, V.S., J.S. Marchant, and H.M. Said. (2008). Apical membrane targeting and trafficking of the human proton-coupled transporter in polarized epithelia. Am. J. Physiol. Cell Physiol. 294: C233-240.

Sugihara, J., I. Smirnova, V. Kasho, and H.R. Kaback. (2011). Sugar recognition by CscB and LacY. Biochemistry 50: 11009-11014.

Sugimoto, N., T. Iwaki, S. Chardwiriyapreecha, M. Shimazu, M. Kawano, T. Sekito, K. Takegawa, and Y. Kakinuma. (2011). Atg22p, a vacuolar membrane protein involved in the amino acid compartmentalization of Schizosaccharomyces pombe. Biosci. Biotechnol. Biochem. 75: 385-387.

Sugita, T. and K. Koketsu. (2022). Transporter Engineering Enables the Efficient Production of Lacto--triose II and Lacto--tetraose in. J Agric Food Chem 70: 5106-5114.

Suman, T.Y., S.Y. Kim, D.H. Yeom, Y. Jang, T.Y. Jeong, and J. Jeon. (2023). Transcriptome and computational approaches highlighting the molecular regulation of Zacco platypus induced by mesocosm exposure to common disinfectant chlorine. Chemosphere 319: 137989.

Sun, F., X. Cao, D. Yu, D. Hu, Z. Yan, Y. Fan, C. Wang, and A. Wu. (2022). AaTAS1 and AaMFS1 genes for biosynthesis or efflux transport of tenuazonic acid and pathogenicity of Alternaria alternata. Mol. Plant Microbe Interact. [Epub: Ahead of Print]

Sun, L., X. Zeng, C. Yan, X. Sun, X. Gong, Y. Rao, and N. Yan. (2012). Crystal structure of a bacterial homologue of glucose transporters GLUT1-4. Nature 490: 361-366.

Sun, M. and Q. Zheng. (2019). Key Factors in Conformation Transformation of an Important Neuron.ic Protein Glucose Transport 3 Revealed by Molecular Dynamics Simulation. ACS Chem Neurosci. [Epub: Ahead of Print]

Sun, Y. and C.K. Vanderpool. (2011). Regulation and function of Escherichia coli sugar efflux transporter A (SetA) during glucose-phosphate stress. J. Bacteriol. 193: 143-153.

Sutter, M.L., L. Console, A.F. Fahner, S.L. Samodelov, Z. Gai, G. Ciarimboli, C. Indiveri, G.A. Kullak-Ublick, and M. Visentin. (2021). The role of cholesterol recognition (CARC/CRAC) mirror codes in the allosterism of the human organic cation transporter 2 (OCT2, SLC22A2). Biochem Pharmacol 194: 114840.

Suzawa, K., A. Yukita, T. Hayata, T. Goto, H. Danno, T. Michiue, K.W. Cho, and M. Asashima. (2007). Xenopus glucose transporter 1 (xGLUT1) is required for gastrulation movement in Xenopus laevis. Int J Dev Biol 51: 183-190.

Swain, K., I. Casabon, L.D. Eltis, and W.W. Mohn. (2012). Two transporters essential for reassimilation of novel cholate metabolites by Rhodococcus jostii RHA1. J. Bacteriol. 194: 6720-6727.

Sweet, D.H. and J.B. Pritchard. (1999). rOCT2 is a basolateral potential-driven carrier, not an organic cation/proton exchanger. Am. J. Physiol. 277: F890-898.

Tahlan, K., S.K. Ahn, A. Sing, T.D. Bodnaruk, A.R. Willems, A.R. Davidson, and J.R. Nodwell. (2007). Initiation of actinorhodin export in Streptomyces coelicolor. Mol. Microbiol. 63: 937-940.

Tailor, C.S., B.J. Willett, and D. Kabat. (1999). A putatve cell surface receptor for anemia-inducing feline leukemia virus subgroup C is a member of a transporter superfamily. Virology 73: 6500-6505.

Takahashi, M., H. Kishimoto, Y. Shirasaka, and K. Inoue. (2020). Functional characterization of monocarboxylate transporter 12 (SLC16A12/MCT12) as a facilitative creatine transporter. Drug Metab Pharmacokinet. [Epub: Ahead of Print]

Takanaga H. and Frommer WB. (2010). Facilitative plasma membrane transporters function during ER transit. FASEB J. 24(8):2849-58.

Tamai, I., R. Ohashi, J. Nezu, H. Yabuuchi, A. Oku, M. Shimane, Y. Sai, and A. Tsuji. (1998). Molecular and functional identification of sodium ion-dependent, high affinity human carnitine transporter OCTN2. J. Biol. Chem. 273: 20378-20382.

Tamayo, E., B. Nada, I. Hafermann, and J.P. Benz. (2024). Correlating sugar transporter expression and activities to identify transporters for an orphan sugar substrate. Appl. Microbiol. Biotechnol. 108: 83.

Tan, G. and F. Meier-Abt. (2021). Differential expression of hydroxyurea transporters in normal and polycythemia vera hematopoietic stem and progenitor cell subpopulations. Exp Hematol. [Epub: Ahead of Print]

Tan, M., Q. Pan, C. Yu, X. Zhai, J. Gu, L. Tao, and D. Xu. (2024). PIGT promotes cell growth, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking. J Transl Med 22: 5.

Tan, P.K., T.M. Ostertag, and J.N. Miner. (2016). Mechanism of high affinity inhibition of the human urate transporter URAT1. Sci Rep 6: 34995.

Tanabe, T., H. Nakao, T. Kuroda, T. Tsuchiya, and S. Yamamoto. (2006). Involvement of the Vibrio parahaemolyticus pvsC gene in export of the siderophore vibrioferrin. Microbiol Immunol 50: 871-876.

Tanabe, T., T. Funahashi, H. Nakao, S.-I. Miyoshi, S. Shinoda, and S. Yamamoto. (2003). Identification and characterization of genes required for biosynthesis and transport of the siderophore vibrioferrin in Vibrio parahaemolyticus. J. Bacteriol. 185: 6938-6949.

Tanaka, M., Y. Miyamoto, K. Sasa, K. Yoshimura, A. Yamada, T. Shirota, and R. Kamijo. (2022). Low oxygen tension suppresses the death of chondrocyte-like ATDC5 cells induced by interleukin-1ß. In Vitro Cell Dev Biol Anim. [Epub: Ahead of Print]

Tang, G., B. Jiang, Y. Huang, M. Fu, L. Wu, and R. Wang. (2011). Identification of a novel bacterial k(+) channel. J. Membr. Biol. 242: 153-164.

Tanner, W. (2000). The Chlorella hexose/H+-symporters. Int Rev Cytol 200: 101-141.

Tavoulari, S. and S. Frillingos. (2008). Substrate selectivity of the melibiose permease (MelY) from Enterobacter cloacae. J. Mol. Biol. 376: 681-693.

Taylor, C.A., K.N. Stanley, and A.D. Shirras. (1997). The Orct gene of Drosophila melanogaster codes for a putative organic cation transporter with six or 12 transmembrane domains. Gene 201: 69-74.

Teijeira, F., R.V. Ullán, S.M. Guerra, C. García-Estrada, I. Vaca, and J.F. Martín. (2009). The transporter CefM involved in translocation of biosynthetic intermediates is essential for cephalosporin production. Biochem. J. 418: 113-124.

Tejada-Jiménez, M., A. Galván, and E. Fernández. (2011). Algae and humans share a molybdate transporter. Proc. Natl. Acad. Sci. USA 108: 6420-6425.

Tenreiro, S., P.A. Nunes, C.A. Viegas, M.S. Neves, M.C. Teixeira, M.G. Cabral, and I. Sá-Correia. (2002). AQR1 gene (ORF YNL065w) encodes a plasma membrane transporter of the major facilitator superfamily that confers resistance to short-chain monocarboxylic acids and quinidine in Saccharomyces cerevisiae. Biochem. Biophys. Res. Commun. 292: 741-748.

Teranishi, Y., M. Inoue, N.G. Yamamoto, T. Kihara, B. Wiehager, T. Ishikawa, B. Winblad, S. Schedin-Weiss, S. Frykman, and L.O. Tjernberg. (2015). Proton myo-inositol cotransporter is a novel γ-secretase associated protein that regulates Aβ production without affecting Notch cleavage. FEBS J. 282: 3438-3451.

Thévenod, F., R. Herbrechter, C. Schlabs, A. Pethe, W.K. Lee, N.A. Wolff, and E. Roussa. (2023). Role of the SLC22A17/lipocalin-2 receptor in renal endocytosis of proteins/metalloproteins: A focus on iron- and cadmium-binding proteins. Am. J. Physiol. Renal Physiol. [Epub: Ahead of Print]

Thompson, S.A., E.V. Maani, A.H. Lindell, C.J. King, and J.V. McArthur. (2007). Novel tetracycline resistance determinant isolated from an environmental strain of Serratia marcescens. Appl. Environ. Microbiol. 73: 2199-2206.

Tian, W., J. Qin, C. Lian, Q. Yao, and X. Wang. (2022). Identification of a major facilitator superfamily protein that is beneficial to L-lactic acid production by Bacillus coagulans at low pH. BMC Microbiol 22: 310.

Tirosh, O., N. Sigal, A. Gelman, N. Sahar, N. Fluman, S. Siemion, and E. Bibi. (2012). Manipulating the drug/proton antiport stoichiometry of the secondary multidrug transporter MdfA. Proc. Natl. Acad. Sci. USA 109: 12473-12478.

Tomitori, H., K. Kashiwagi, K. Sakata, Y. Kakinuma, and K. Igarashi. (1999). Identification of a gene for a polyamine transport protein in yeast. J. Biol. Chem. 274: 3265-3267.

Truernit, E., J. Schmid, P. Epple, J. Illig, and N. Sauer. (1996). The sink-specific and stress-regulated Arabidopsis STP4 gene: enhanced expression of a gene encoding a monosaccharide transporter by wounding, elicitors, and pathogen challenge. Plant Cell 8: 2169-2182.

Truernit, E., R. Stadler, K. Baier, and N. Sauer. (1999). A male gametophyte-specific monosaccharide transporter in Arabidopsis. Plant J. 17: 191-201.

Truong, D.M., G. Kaler, A. Khandelwal, P.W. Swaan, and S.K. Nigam. (2008). Multi-level analysis of organic anion transporters 1, 3, and 6 reveals major differences in structural determinants of antiviral discrimination. J. Biol. Chem. 283(13): 8654-8663.

Truong-Bolduc, Q.C., J. Strahilevitz, and D.C. Hooper. (2006). NorC, a new efflux pump regulated by MgrA of Staphylococcus aureus. Antimicrob. Agents Chemother. 50: 1104-1107.

Truong-Bolduc, Q.C., P.M. Dunman, J. Strahilevitz, S.J. Projan, and D.C. Hooper. (2005). MgrA is a multiple regulator of two new efflux pumps in Staphylococcus aureus. J. Bacteriol. 187: 2395-2405.

Truong-Bolduc, Q.C., Y. Wang, and D.C. Hooper. (2021). Staphylococcus aureus Tet38 Efflux Pump Structural Modeling and Roles of Essential Residues in Drug Efflux and Host Cell Internalization. Infect. Immun. 89:.

Tse, Y.M., M. Yu, and J.S. Tsang. (2009). Topological analysis of a haloacid permease of a Burkholderia sp. bacterium with a PhoA-LacZ reporter. BMC Microbiol 9: 233.

Tsuchida, H., N. Anzai, H.J. Shin, M.F. Wempe, P. Jutabha, A. Enomoto, S.H. Cha, T. Satoh, M. Ishida, H. Sakurai, and H. Endou. (2010). Identification of a novel organic anion transporter mediating carnitine transport in mouse liver and kidney. Cell Physiol Biochem 25: 511-522.

Tsutsumi, R., B. Ueberheide, F.X. Liang, B.G. Neel, R. Sakai, and Y. Saito. (2024). Endocytic vesicles act as vehicles for glucose uptake in response to growth factor stimulation. Nat Commun 15: 2843.

Tucker, D.F., J.T. Sullivan, K.A. Mattia, C.R. Fisher, T. Barnes, M.N. Mabila, R. Wilf, C. Sulli, M. Pitts, R.J. Payne, M. Hall, D. Huston-Paterson, X. Deng, E. Davidson, S.H. Willis, B.J. Doranz, R. Chambers, and J.B. Rucker. (2018). Isolation of state-dependent monoclonal antibodies against the 12-transmembrane domain glucose transporter 4 using virus-like particles. Proc. Natl. Acad. Sci. USA. [Epub: Ahead of Print]

Turner, M.S. and J.D. Helmann. (2000). Mutations in multidrug efflux homologs, sugar isomerases, and antimicrobial biosynthesis genes differentially elevate activity of the σX and σW factors in Bacillus subtilis. J. Bacteriol. 182: 5202-5210.

Uebanso, T., M. Fukui, C. Naito, T. Shimohata, K. Mawatari, and A. Takahashi. (2023). SLC16a6, mTORC1, and Autophagy Regulate Ketone Body Excretion in the Intestinal Cells. Biology (Basel) 12:.

Uebe, R. and D. Schüler. (2016). Magnetosome biogenesis in magnetotactic bacteria. Nat. Rev. Microbiol. 14: 621-637.

Uehara, M., A. Fukumoto, H. Omote, and M. Hiasa. (2024). Polyamine release and vesicular polyamine transporter expression in megakaryoblastic cells and platelets. Biochim. Biophys. Acta. Gen Subj 1868: 130610.

Uemura, T., K. Tachihara, H. Tomitori, K. Kashiwagi, K. Igarashi. (2005). Characteristics of the polyamine transporter TPO1 and regulation of its activity and cellular localization by phosphorylation. J. Biol. Chem. 280: 9646-9652.

Uldry, M., M. Ibberson, J.D. Horisberger, J.Y. Chatton, B.M. Riederer, and B. Thorens. (2001). Identification of a mammalian H+-myo-inositol symporter expressed predominantly in the brain. EMBO J. 20: 4467-4477.

Uldry, M., M. Ibberson, M. Hosokawa, and B. Thorens. (2002). GLUT2 is a high affinity glucosamine transporter. FEBS Lett. 524: 199-203.

Ullán, R.V., G. Liu, J. Casqueiro, S. Gutiérrez, O. Bañuelos, and J.F. Martín. (2002). The cefT gene of Acremonium chrysogenum C10 encodes a putative multidrug efflux pump protein that significantly increases cephalosporin C production. Mol. Genet. Genomics 267: 673-683.

Unkles SE., Karabika E., Symington VF., Cecile JL., Rouch DA., Akhtar N., Cromer BA. and Kinghorn JR. (2012). Alanine scanning mutagenesis of a high-affinity nitrate transporter highlights the requirement for glycine and asparagine residues in the two nitrate signature motifs. Biochem J. 447(1):35-42.

Unkles, S.E., K.L. Hawker, C. Grieve, E.I. Campbell, P. Montague, and J.R. Kinghorn. (1991). crnA encodes a nitrate transporter in Aspergillus nidulans. Proc. Natl. Acad. Sci. USA 88: 204-208.

Unkles, S.E., V.F. Symington, Z. Kotur, Y. Wang, M.Y. Siddiqi, J.R. Kinghorn, and A.D. Glass. (2011). Physiological and biochemical characterization of AnNitA, the Aspergillus nidulans high-affinity nitrite transporter. Eukaryot. Cell. 10: 1724-1732.

Unno, K., K. Taguchi, Y. Takagi, T. Hase, S. Meguro, and Y. Nakamura. (2023). Mouse Models with SGLT2 Mutations: Toward Understanding the Role of SGLT2 beyond Glucose Reabsorption. Int J Mol Sci 24:.

Uwai, Y., Y. Ozeki, T. Isaka, H. Honjo, and K. Iwamoto. (2011). Inhibitory effect of caffeic acid on human organic anion transporters hOAT1 and hOAT3: a novel candidate for food-drug interaction. Drug Metab Pharmacokinet 26: 486-493.

Vallon, V. (2020). Glucose transporters in the kidney in health and disease. Pflugers Arch. [Epub: Ahead of Print]

Valmeekam, V., Y.L. Loh, and M.J. San Francisco. (2001). Control of exuT activity for galacturonate transport by the negative regulator ExuR in Erwinia chrysanthemi EC16. Mol. Plant Microbe Interact. 14: 816-820.

Van Camp, B.M., R.R. Crow, Y. Peng, and M.F. Varela. (2007). Amino acids that confer transport of raffinose and maltose sugars in the raffinose permease (RafB) of Escherichia coli as implicated by spontaneous mutations at Val-35, Ser-138, Ser-139, Gly-389 and Ile-391. J. Membr. Biol. 220: 87-95.

van Geest, F.S., M.E. Meima, K.E. Stuurman, N.I. Wolf, M.S. van der Knaap, C.F. Lorea, F.O. Poswar, F. Vairo, N. Brunetti-Pierri, G. Cappuccio, P. Bakhtiani, S.A. de Munnik, R.P. Peeters, W.E. Visser, and S. Groeneweg. (2020). Clinical and functional consequences of C-terminal variants in MCT8: a case series. J Clin Endocrinol Metab. [Epub: Ahead of Print]

van Vliet, A.R., S. De Tito, E. Almacellas, and S.A. Tooze. (2023). Imaging ATG9A, a Multi-Spanning Membrane Protein. J Vis Exp.

van Wezel, G.P., K. Mahr, M. König, B.A. Traag, E.F. Pimentel-Schmitt, A. Willimek, and F. Titgemeyer. (2005). GlcP constitutes the major glucose uptake system of Streptomyces coelicolor A3(2). Mol. Microbiol. 55: 624-636.

Vancamp, P. and V.M. Darras. (2017). From zebrafish to human: A comparative approach to elucidate the role of the thyroid hormone transporter MCT8 during brain development. Gen Comp Endocrinol. [Epub: Ahead of Print]

Vardy, E., S. Steiner-Mordoch, and S. Schuldiner. (2005). Characterization of bacterial drug antiporters homologous to mammalian neurotransmitter transporters. J. Bacteriol. 187: 7518-7525.

Vasamsetti, B.M.K., K. Chon, C.Y. Yoon, J. Kim, J.Y. Choi, S. Hwang, and K.H. Park. (2023). Transcriptome Profiling of Etridiazole-Exposed Zebrafish () Embryos Reveals Pathways Associated with Cardiac and Ocular Toxicities. Int J Mol Sci 24:.

Västermark, &.#.1.9.7.;., J.A. Jacobsson, &.#.1.9.7.;. Johansson, R. Fredriksson, U. Gyllensten, and H.B. Schiöth. (2012). Polymorphisms in sh2b1 and spns1 loci are associated with triglyceride levels in a healthy population in northern Sweden. J Genet 91: 237-240.

Västermark, A. and M.H. Saier. (2014). Major Facilitator Superfamily (MFS) evolved without 3-transmembrane segment unit rearrangements. Proc. Natl. Acad. Sci. USA 111: E1162-1163.

Västermark, A., B. Lunt, and M. Saier. (2014). Major facilitator superfamily porters, LacY, FucP and XylE of Escherichia coli appear to have evolved positionally dissimilar catalytic residues without rearrangement of 3-TMS repeat units. J. Mol. Microbiol. Biotechnol. 24: 82-90.

Vela-Corcía, D., D. Aditya Srivastava, A. Dafa-Berger, N. Rotem, O. Barda, and M. Levy. (2019). MFS transporter from Botrytis cinerea provides tolerance to glucosinolate-breakdown products and is required for pathogenicity. Nat Commun 10: 2886.

Verheijen, F.W., E. Verbeek, N. Aula, C.E. Beerens, A.C. Havelaar, M. Joosse, L. Peltonen, R. Aula, H. Galjaard, P.J. van der Spek, and G.M. Mancini. (1999). A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases. Nature Genet. 23: 462-465.

Versaw, W.K. (1995). A phosphate-repressible, high-affinity phosphate permease is encoded by the pho-5+ gene of Neurospora crassa. Gene 153: 135-139.

Vieira, N., M. Casal, B. Johansson, D.M. MacCallum, A.J. Brown, and S. Paiva. (2010). Functional specialization and differential regulation of short-chain carboxylic acid transporters in the pathogen Candida albicans. Mol. Microbiol. 75: 1337-1354.

Viigand, K., K. Tammus, and T. Alamäe. (2005). Clustering of MAL genes in Hansenula polymorpha: cloning of the maltose permease gene and expression from the divergent intergenic region between the maltose permease and maltase genes. FEMS Yeast Res 5: 1019-1028.

Vilhena, C., E. Kaganovitch, J.Y. Shin, A. Grünberger, S. Behr, I. Kristoficova, S. Brameyer, D. Kohlheyer, and K. Jung. (2017). A single-cell view of the BtsSR/YpdAB pyruvate sensing network in Escherichia coli and its biological relevance. J. Bacteriol. [Epub: Ahead of Print]

Villagra, N.A., A.A. Hidalgo, C.A. Santiviago, C.P. Saavedra, and G.C. Mora. (2008). SmvA, and not AcrB, is the major efflux pump for acriflavine and related compounds in Salmonella enterica serovar Typhimurium. J Antimicrob Chemother 62: 1273-1276.

Visser, W.E., N.J. Philp, T.B. van Dijk, W. Klootwijk, E.C. Friesema, J. Jansen, P.W. Beesley, A.G. Ianculescu, and T.J. Visser. (2009). Evidence for a homodimeric structure of human monocarboxylate transporter 8. Endocrinology 150: 5163-5170.

Visser, W.F., C.W. van Roermund, L. Ijlst, H.R. Waterham, and R.J. Wanders. (2007). Metabolite transport across the peroxisomal membrane. Biochem. J. 401: 365-375.

Vitrac, H., V.K.P.S. Mallampalli, M. Bogdanov, and W. Dowhan. (2019). The lipid-dependent structure and function of LacY can be recapitulated and analyzed in phospholipid-containing detergent micelles. Sci Rep 9: 11338.

Vitrac, H., V.K.P.S. Mallampalli, S. Azinas, and W. Dowhan. (2020). Structural and Functional Adaptability of Sucrose and Lactose Permeases from to the Membrane Lipid Composition. Biochemistry. [Epub: Ahead of Print]

Vitreschak, A.G., D.A. Rodionov, A.A. Mironov, and M.S. Gelfand. (2002). Regulation of riboflavin biosynthesis and transport genes in bacteria by transcriptional and translational attenuation. Nucleic Acids Res 30: 3141-3151.

Vogl, C., C.M. Klein, A.F. Batke, M.E. Schweingruber, and J. Stolz. (2008). Characterization of Thi9, a novel thiamine (Vitamin B1) transporter from Schizosaccharomyces pombe. J. Biol. Chem. 283: 7379-7389.

Volkova M., Mandikova J., Barta P., Navratilova L., Laznickova A. and Trejtnar F. (2015). The in vivo disposition and in vitro transmembrane transport of two model radiometabolites of DOTA-conjugated receptor-specific peptides labelled with (177) Lu. J Labelled Comp Radiopharm. 58(13-14):483-9.

von Rozycki, T., M.R. Yen, E.E. Lende, and M.H. Saier, Jr. (2004). The YedZ family: possible heme binding proteins that can be fused to transporters and electron carriers. J. Mol. Microbiol. Biotechnol. 8: 129-140.

Wagai, S., A. Kasamatsu, M. Iyoda, F. Hayashi, K. Hiroshima, S. Yoshimura, I. Miyamoto, D. Nakashima, Y. Endo-Sakamoto, M. Shiiba, H. Tanzawa, and K. Uzawa. (2019). UNC93B1 promotes tumoral growth by controlling the secretion level of granulocyte macrophage colony-stimulating factor in human oral cancer. Biochem. Biophys. Res. Commun. 513: 81-87.

Wagenaars, F., P. Cenijn, M. Scholze, C. Frädrich, K. Renko, J. Köhrle, and T. Hamers. (2024). Screening for endocrine disrupting chemicals inhibiting monocarboxylate 8 (MCT8) transporter facilitated thyroid hormone transport using a modified nonradioactive assay. Toxicol In Vitro 96: 105770.

Walters, D.K., B.K. Arendt, and D.F. Jelinek. (2013). CD147 regulates the expression of MCT1 and lactate export in multiple myeloma cells. Cell Cycle 12: 3175-3183.

Wambo, T.O., L.Y. Chen, C. Phelix, and G. Perry. (2017). Affinity and path of binding xylopyranose unto E. coli xylose permease. Biochem. Biophys. Res. Commun. [Epub: Ahead of Print]

Wang C., Shen Y., Hou J., Suo F. and Bao X. (2013). An assay for functional xylose transporters in Saccharomyces cerevisiae. Anal Biochem. 442(2):241-8.

Wang M., Qi H., Li J., Xu Y. and Zhang H. (2015). Transmembrane transport of steviol glucuronide and its potential interaction with selected drugs and natural compounds. Food Chem Toxicol. 86:217-24.

Wang, C., F.Q. Zhao, J. Liu, and H. Liu. (2020). Short communication: The essential role of N-glycosylation in the transport activity of bovine peptide transporter 2. J Dairy Sci. [Epub: Ahead of Print]

Wang, C., L. Yang, A.A. Shah, E.S. Choi, and S.W. Kim. (2015). Dynamic interplay of multidrug transporters with TolC for isoprenol tolerance in Escherichia coli. Sci Rep 5: 16505.

Wang, C., X. Bao, Y. Li, C. Jiao, J. Hou, Q. Zhang, W. Zhang, W. Liu, and Y. Shen. (2015). Data set for cloning and characterization of heterologous transporters in Saccharomyces cerevisiae and identification of important amino acids for xylose utilization. Data Brief 4: 119-126.

Wang, D., H. Wu, J. Yang, M. Li, C. Ling, Z. Gao, H. Lu, H. Shen, and Y. Tang. (2022). Loss of SLC46A1 decreases tumor iron content in hepatocellular carcinoma. Hepatol Commun. [Epub: Ahead of Print]

Wang, J., T. Li, X. Wu, and Z. Zhao. (2014). Molecular cloning and functional analysis of a H+-dependent phosphate transporter gene from the ectomycorrhizal fungus Boletus edulis in southwest China. Fungal Biol 118: 453-461.

Wang, N., X. Jiang, S. Zhang, A. Zhu, Y. Yuan, H. Xu, J. Lei, and C. Yan. (2020). Structural basis of human monocarboxylate transporter 1 inhibition by anti-cancer drug candidates. Cell. [Epub: Ahead of Print]

Wang, Q. and M.E. Morris. (2007). The role of monocarboxylate transporter 2 and 4 in the transport of γ-hydroxybutyric acid in mammalian cells. Drug Metab Dispos 35: 1393-1399.

Wang, Q., H. Li, and A.F. Post. (2000). Nitrate assimilation genes of the marine diazotrophic, filamentous cyanobacterium Trichodesmium sp. strain WH9601. J. Bacteriol. 182: 1764-1767.

Wang, S. and L. Qin. (2022). Homeostatic medicine: a strategy for exploring health and disease. Curr Med (Cham) 1: 16.

Wang, S., K. Wang, K. Song, P. Li, D. Li, Y. Sun, Y. Mei, C. Xu, and M. Liao. (2024). Structures of the essential efflux pump EfpA from reveal the mechanisms of substrate transport and small-molecule inhibition. Res Sq.

Wang, T., J. Wang, X. Hu, X.J. Huang, and G.X. Chen. (2020). Current understanding of glucose transporter 4 expression and functional mechanisms. World J. Biol. Chem. 11: 76-98.

Wang, T., Y. Wang, A. Montero-Pedrazuela, L. Prensa, A. Guadaño-Ferraz, and E. Rausell. (2023). Thyroid Hormone Transporters MCT8 and OATP1C1 Are Expressed in Projection Neuron.s and Interneurons of Basal Ganglia and Motor Thalamus in the Adult Human and Macaque Brains. Int J Mol Sci 24:.

Wang, W. and H.W. van Veen. (2012). Basic residues R260 and K357 affect the conformational dynamics of the major facilitator superfamily multidrug transporter LmrP. PLoS One 7: e38715.

Wang, W., A.A. Guffanti, Y. Wei, M. Ito, and T.A. Krulwich. (2000). Two types of Bacillus subtilis tetA(L) deletion strains reveal the physiological importance of TetA(L) in K+ acquisition as well as in Na+, alkali, and tetracycline resistance. J. Bacteriol. 182: 2088-2095.

Wang, W.A. and N. Demaurex. (2022). The mammalian trafficking chaperone protein UNC93B1 maintains the ER calcium sensor STIM1 in a dimeric state primed for translocation to the ER cortex. J. Biol. Chem. 298: 101607.

Wang, X., R.I. Sarker, and P.C. Maloney. (2006). Analysis of substrate-binding elements in OxlT, the oxalate:formate antiporter of Oxalobacter formigenes. Biochemistry 45: 10344-10350.

Wang, Y., T. Wang, A. Montero-Pedrazuela, A. Guadaño-Ferraz, and E. Rausell. (2023). Thyroid Hormone Transporters MCT8 and OATP1C1 Are Expressed in Pyramidal Neuron.s and Interneurons in the Adult Motor Cortex of Human and Macaque Brain. Int J Mol Sci 24:.

Wang, Y., W. Li, Y. Siddiqi, V.F. Symington, J.R. Kinghorn, S.E. Unkles, and A.D. Glass. (2008). Nitrite transport is mediated by the nitrite-specific high-affinity NitA transporter and by nitrate transporters NrtA, NrtB in Aspergillus nidulans. Fungal Genet Biol 45: 94-102.

Watson, E.T., M.M. Pauers, M.J. Seibert, J.D. Vevea, and E.R. Chapman. (2023). Synaptic vesicle proteins are selectively delivered to axons in mammalian neurons. Elife 12:.

Wei, H., K. Vienken, R. Weber, S. Bunting, N. Requena, and R. Fischer. (2004). A putative high affinity hexose transporter, hxtA, of Aspergillus nidulans is induced in vegetative hyphae upon starvation and in ascogenous hyphae during cleistothecium formation. Fungal Genet Biol 41: 148-156.

Wei, X., Y. Fu, R. Yu, L. Wu, Z. Wu, P. Tian, S. Li, X. Yang, and M. Yang. (2022). Comprehensive sequence and expression profile analysis of the phosphate transporter gene family in soybean. Sci Rep 12: 20883.

Weijers, R.N. (2020). Fundamentals about onset and progressive disease character of type 2 diabetes mellitus. World J Diabetes 11: 165-181.

Wichers, J.S., P. Mesén-Ramírez, G. Fuchs, J. Yu-Strzelczyk, J. Stäcker, H. von Thien, A. Alder, I. Henshall, B. Liffner, G. Nagel, C. Löw, D. Wilson, T. Spielmann, S. Gao, T.W. Gilberger, A. Bachmann, and J. Strauss. (2022). PMRT1, a -Specific Parasite Plasma Membrane Transporter, Is Essential for Asexual and Sexual Blood Stage Development. mBio 13: e0062322.

Widiasih Widiyanto, T., X. Chen, S. Iwatani, H. Chibana, and S. Kajiwara. (2019). Role of major facilitator superfamily transporter Qdr2p in biofilm formation by Candida glabrata. Mycoses 62: 1154-1163.

Wieczorke, R., S. Krampe, T. Weierstall, K. Freidel, C.P. Hollenberg, and E. Boles. (1999). Concurrent knock-out of at least 20 transporter genes is required to block uptake of hexoses in Saccharomyces cerevisiae. FEBS Lett. 464: 123-128.

Williams, P.A. and L.E. Shaw. (1997). mucK, a gene in Acinetobacter calcoaceticus ADP1 (BD413), encodes the ability to grow on exogenous cis,cis-muconate as the sole carbon source. J. Bacteriol. 179: 5935-5942.

Wilpert, N.M., M. Krueger, R. Opitz, D. Sebinger, S. Paisdzior, B. Mages, A. Schulz, J. Spranger, E.K. Wirth, H. Stachelscheid, P. Mergenthaler, P. Vajkoczy, H. Krude, P. Kühnen, I. Bechmann, and H. Biebermann. (2020). Spatiotemporal Changes of Cerebral Monocarboxylate Transporter 8 Expression. Thyroid. [Epub: Ahead of Print]

Wilson MR., Kugel S., Huang J., Wilson LJ., Wloszczynski PA., Ye J., Matherly LH. and Hou Z. (2015). Structural determinants of human proton-coupled folate transporter oligomerization: role of GXXXG motifs and identification of oligomeric interfaces at transmembrane domains 3 and 6. Biochem J. 469(1):33-44.

Wilson, M.C., D. Meredith, J.E. Fox, C. Manoharan, A.J. Davies, and A.P. Halestrap. (2005). Basigin (CD147) is the target for organomercurial inhibition of monocarboxylate transporter isoforms 1 and 4: the ancillary protein for the insensitive MCT2 is EMBIGIN (gp70). J. Biol. Chem. 280: 27213-27221.

Wilson, M.C., V.N. Jackson, C. Heddle, N.T. Price, H. Pilegaard, C. Juel, A. Bonen, I. Montgomery, O.F. Hutter, and A.P. Halestrap. (1998). Lactic acid efflux from white skeletal muscle is catalyzed by the monocarboxylate transporter isoform MCT3. J. Biol. Chem. 273: 15920-15926.

Wilson, M.R., Z. Hou, and L.H. Matherly. (2014). Substituted Cysteine Accessibility Reveals a Novel Transmembrane 2-3 Reentrant Loop and Functional Role for Transmembrane Domain 2 in the Human Proton-coupled Folate Transporter. J. Biol. Chem. 289: 25287-25295.

Wilson-O''Brien, A.L., N. Patron, and S. Rogers. (2010). Evolutionary ancestry and novel functions of the mammalian glucose transporter (GLUT) family. BMC Evol Biol 10: 152.

Wirth, E.K., S.Y. Sheu, J. Chiu-Ugalde, R. Sapin, M.O. Klein, I. Mossbrugger, L. Quintanilla-Martinez, M.H. de Angelis, H. Krude, T. Riebel, K. Rothe, J. Köhrle, K.W. Schmid, U. Schweizer, and A. Grüters. (2011). Monocarboxylate transporter 8 deficiency: altered thyroid morphology and persistent high triiodothyronine/thyroxine ratio after thyroidectomy. Eur J Endocrinol 165: 555-561.

Wirth, E.K., U. Schweizer, and J. Köhrle. (2014). Transport of thyroid hormone in brain. Front Endocrinol (Lausanne) 5: 98.

Wirth, J., F. Chopin, V. Santoni, G. Viennois, P. Tillard, A. Krapp, L. Lejay, F. Daniel-Vedele, and A. Gojon. (2007). Regulation of root nitrate uptake at the NRT2.1 protein level in Arabidopsis thaliana. J. Biol. Chem. 282: 23541-23552.

Witkowska K., Smith KM., Yao SY., Ng AM., O'Neill D., Karpinski E., Young JD. and Cheeseman CI. (2012). Human SLC2A9a and SLC2A9b isoforms mediate electrogenic transport of urate with different characteristics in the presence of hexoses. Am J Physiol Renal Physiol. 303(4):F527-39.

Wolf, L., M. Föller, and M. Feger. (2023). The impact of SGLT2 inhibitors on αKlotho in renal MDCK and HK-2 cells. Front Endocrinol (Lausanne) 14: 1069715.

Wollack, J.B., B. Makori, S. Ahlawat, R. Koneru, S.C. Picinich, A. Smith, I.D. Goldman, A. Qiu, P.D. Cole, J. Glod, and B. Kamen. (2008). Characterization of folate uptake by choroid plexus epithelial cells in a rat primary culture model. J Neurochem 104(6): 1494-1503.

Wood, N.J., T. Alizadeh, D.J. Richardson, S.J. Ferguson, and J.W.B. Moir. (2002). Two domains of a dual-function NarK protein are required for nitrate uptake, the first step of denitrification in Paracoccus pantotrophus. Mol. Microbiol. 44: 157-170.

Woolley, R.C., G. Vediyappan, M. Anderson, M. Lackey, B. Ramasubramanian, B. Jiangping, T. Borisova, J.A. Colmer, A.N. Hamood, C.S. McVay, and J.A. Fralick. (2005). Characterization of the Vibrio cholerae vceCAB multiple-drug resistance efflux operon in Escherichia coli. J. Bacteriol. 187: 5500-5503.

Woolridge, D.P., N. Vazquez-Laslop, P.N. Markham, M.S. Chevalier, E.W. Gerner, and A.A. Neyfakh. (1997). Efflux of the natural polyamine spermidine facilitated by the Bacillus subtilis multidrug transporter Blt. J. Biol. Chem. 272: 8864-8866.

Wright DJ. and Tate CG. (2015). Isolation and characterisation of transport-defective substrate-binding mutants of the tetracycline antiporter TetA(B). Biochim Biophys Acta. 1848(10 Pt A):2261-2270.

Wright, D.C. (2007). Mechanisms of calcium-induced mitochondrial biogenesis and GLUT4 synthesis. Appl Physiol Nutr Metab 32: 840-845.

Wright, M.B., E.A. Howell, and R.F. Gaber. (1996). Amino acid substitutions in membrane-spanning domains of Hol1, a member of the major facilitator superfamily of transporters, confer nonselective cation uptake in Saccharomyces cerevisiae. J. Bacteriol. 178: 7197-7205.

Wu, W., K.T. Bush, H.C. Liu, C. Zhu, R. Abagyan, and S.K. Nigam. (2015). Shared Ligands Between Organic Anion Transporters (OAT1 and OAT6) and Odorant Receptors. Drug Metab Dispos 43: 1855-1863.

Wu, W., N. Jamshidi, S.A. Eraly, H.C. Liu, K.T. Bush, B.O. Palsson, and S.K. Nigam. (2013). Multispecific drug transporter slc22a8 (oat3) regulates multiple metabolic and signaling pathways. Drug Metab Dispos 41: 1825-1834.

Wu, X., R. Kekuda, W. Huang, Y.J. Fei, F.H. Leibach, J. Chen, S.J. Conway, and V. Ganapathy. (1998). Identity of the organic cation transporter OCT3 as the extraneuronal monoamine transporter (uptake2) and evidence for the expression of the transporter in the brain. J. Biol. Chem. 273: 32776-32786.

Wu, X., Y.J. Fei, W. Huang, C. Chancy, F.H. Leibach, and V. Ganapathy. (1999). Identity of the F52F12.1 gene product in Caenorhabditis elegans as an organic cation transporter. Biochim. Biophys. Acta. 1418: 239-244.

Wuchiyama, J., M. Kimura, and I. Yamaguchi. (2000). A trichothecene efflux pump encoded by Tri102 in the biosynthesis gene cluster of Fusarium graminearum. J Antibiot (Tokyo) 53: 196-200.

Wunderlich, J. (2022). Updated List of Transport Proteins in. Front Cell Infect Microbiol 12: 926541.

Xi, Y., T. Zhan, H. Xu, J. Chen, C. Bi, F. Fan, and X. Zhang. (2021). Characterization of JEN family carboxylate transporters from the acid-tolerant yeast Pichia kudriavzevii and their applications in succinic acid production. Microb Biotechnol. [Epub: Ahead of Print]

Xie, X., H. Lin, X. Peng, C. Xu, Z. Sun, K. Jiang, A. Huang, X. Wu, N. Tang, A. Salvioli, P. Bonfante, and B. Zhao. (2016). Arbuscular Mycorrhizal Symbiosis Requires a Phosphate Transceptor in the Gigaspora margarita Fungal Symbiont. Mol Plant 9: 1583-1608.

Xie, Y., J. Ma, X. Qin, Q. Li, and J. Ju. (2017). Identification and utilization of two important transporters: SgvT1 and SgvT2, for griseoviridin and viridogrisein biosynthesis in Streptomyces griseoviridis. Microb Cell Fact 16: 177.

Xiong, Y., D. Delic, S. Zeng, X. Chen, C. Chu, A.A. Hasan, B.K. Krämer, T. Klein, L. Yin, and B. Hocher. (2022). Regulation of SARS CoV-2 host factors in the kidney and heart in rats with 5/6 nephrectomy-effects of salt, ARB, DPP4 inhibitor and SGLT2 blocker. BMC Nephrol 23: 117.

Xu Y., Chen B., Chao H. and Zhou NY. (2013). mhpT encodes an active transporter involved in 3-(3-hydroxyphenyl)propionate catabolism by Escherichia coli K-12. Appl Environ Microbiol. 79(20):6362-8.

Xu, X., J. Chen, H. Xu, and D. Li. (2014). Role of a major facilitator superfamily transporter in adaptation capacity of Penicillium funiculosum under extreme acidic stress. Fungal Genet Biol 69: 75-83.

Yadav, V., M. Kumar, D.K. Deep, H. Kumar, R. Sharma, T. Tripathi, N. Tuteja, A.K. Saxena, and A.K. Johri. (2010). A phosphate transporter from the root endophytic fungus Piriformospora indica plays a role in phosphate transport to the host plant. J. Biol. Chem. 285: 26532-26544.

Yaffe, D., S. Radestock, Y. Shuster, L.R. Forrest, and S. Schuldiner. (2013). Identification of molecular hinge points mediating alternating access in the vesicular monoamine transporter VMAT2. Proc. Natl. Acad. Sci. USA 110: E1332-1341.

Yamada, K., Y. Saijo, H. Nakagami, and Y. Takano. (2016). Regulation of sugar transporter activity for antibacterial defense in Arabidopsis. Science 354: 1427-1430.

Yamada, S., N. Awano, K. Inubushi, E. Maeda, S. Nakamori, K. Nishino, A. Yamaguchi, and H. Takagi. (2006). Effect of drug transporter genes on cysteine export and overproduction in Escherichia coli. Appl. Environ. Microbiol. 72: 4735-4742.

Yamada, Y., J. Sakuma, I. Takeuchi, Y. Yasukochi, K. Kato, M. Oguri, T. Fujimaki, H. Horibe, M. Muramatsu, M. Sawabe, Y. Fujiwara, Y. Taniguchi, S. Obuchi, H. Kawai, S. Shinkai, S. Mori, T. Arai, and M. Tanaka. (2017). Identification of TNFSF13, SPATC1L, SLC22A25 and SALL4 as novel susceptibility loci for atrial fibrillation by an exome‑wide association study. Mol Med Rep 16: 5823-5832.

Yamada, Y., K. Hideka, S. Shiota, T. Kuroda, and T. Tsuchiya. (2006). Gene cloning and characterization of SdrM, a chromosomally-encoded multidrug efflux pump, from Staphylococcus aureus. Biol Pharm Bull 29: 554-556.

Yamada, Y., S. Shiota, T. Mizushima, T. Kuroda, and T. Tsuchiya. (2006). Functional gene cloning and characterization of MdeA, a multidrug efflux pump from Staphylococcus aureus. Biol Pharm Bull 29: 801-804.

Yamagata, A., K. Ito, T. Suzuki, N. Dohmae, T. Terada, and M. Shirouzu. (2024). Structural basis for antiepileptic drugs and botulinum neurotoxin recognition of SV2A. Nat Commun 15: 3027.

Yamaguchi, A., Y. Mukai, T. Sakuma, A. Furugen, K. Narumi, and M. Kobayashi. (2023). Atorvastatin Exerts More Selective Inhibitory Effects on hMCT2 than on hMCT1 and hMCT4. Anticancer Res 43: 3015-3022.

Yanagisawa, H., T. Miyashita, Y. Nakano, and D. Yamamoto. (2003). HSpin1, a transmembrane protein interacting with Bcl-2/Bcl-xL, induces a caspase-independent autophagic cell death. Cell Death Differ. 10: 798-807.

Yanatori, I., Y. Yasui, K. Miura, and F. Kishi. (2012). Mutations of FLVCR1 in posterior column ataxia and retinitis pigmentosa result in the loss of heme export activity. Blood Cells Mol Dis 49: 60-66.

Yang, C., D.A. Rodionov, X. Li, O.N. Laikova, M.S. Gelfand, O.P. Zagnitko, M.F. Romine, A.Y. Obraztsova, K.H. Nealson, and A.L. Osterman. (2006). Comparative genomics and experimental characterization of N-acetylglucosamine utilization pathway of Shewanella oneidensis. J. Biol. Chem. 281: 29872-29885.

Yang, H., G. Qin, Z. Luo, X. Kong, C. Gan, R. Zhang, and W. Jiang. (2022). MFSD4A inhibits the malignant progression of nasopharyngeal carcinoma by targeting EPHA2. Cell Death Dis 13: 332.

Yang, J., X. Xu, and G. Liu. (2012). Amplification of an MFS Transporter Encoding Gene penT Significantly Stimulates Penicillin Production and Enhances the Sensitivity of Penicillium chrysogenum to Phenylacetic Acid. J Genet Genomics 39: 593-602.

Yang, L., J. Li, Y. Li, Y. Zhou, Z. Wang, D. Zhang, J. Liu, and X. Zhang. (2021). Diclofenac impairs the proliferation and glucose metabolism of triple-negative breast cancer cells by targeting the c-Myc pathway. Exp Ther Med 21: 584.

Yang, L., Z. Chen, W. Xiong, H. Ren, E. Zhai, K. Xu, H. Yang, Z. Zhang, L. Ding, Y. He, X. Song, and J. Liu. (2019). High expression of SLC17A9 correlates with poor prognosis in colorectal cancer. Hum Pathol 84: 62-70.

Yang, R., T. Viswanatham, S. Huang, Y. Li, Y. Yu, J. Zhang, J. Chen, M. Herzberg, R. Feng, B.P. Rosen, and C. Rensing. (2024). A Sb(III)-specific efflux transporter from Ensifer adhaerens E-60. Microbiol Res 286: 127830. [Epub: Ahead of Print]

Yang, Y.J., R.P. Singh, X. Lan, C.S. Zhang, D.H. Sheng, and Y.Q. Li. (2019). Whole transcriptome analysis and gene deletion to understand the chloramphenicol resistance mechanism and develop a screening method for homologous recombination in Myxococcus xanthus. Microb Cell Fact 18: 123.

Yao, J. and S.M. Bajjalieh. (2009). SVOP is a nucleotide binding protein. PLoS One 4: e5315.

Yao, X., L. Liu, W. Shao, M. Bai, X. Ding, G. Wang, S. Wang, L. Zheng, Y. Sun, G. Wang, Y. Huang, C. Yu, Z. Song, Y. Bao, S. Yang, and L. Sun. (2023). Tectorigenin targets PKACα to promote GLUT4 expression in skeletal muscle and improve insulin resistance and. Int J Biol Sci 19: 1579-1596.

Yasuda, S., S. Hasui, M. Kobayashi, S. Itagaki, T. Hirano, and K. Iseki. (2008). The mechanism of carrier-mediated transport of folates in BeWo cells: the involvement of heme carrier protein 1 in placental folate transport. Biosci. Biotechnol. Biochem. 72: 329-334.

Ye, L. and P.C. Maloney. (2002). Structure/function relationships in OxlT, the oxalate/formate antiporter of Oxalobacter formigenes: assignment of transmembrane helix 2 to the translocation pathway. J. Biol. Chem. 277: 20372-20378.

Ye, L., Z. Jia, T. Jung, and P.C. Maloney. (2001). Toplogy of OxlT, the oxalate transporter of Oxalobacter formigenes, determined by site-directed fluorescence labeling. J. Bacteriol. 183: 2490-2496.

Yee, S.W., C. Macdonald, D. Mitrovic, X. Zhou, M.L. Koleske, J. Yang, D.B. Silva, P.R. Grimes, D. Trinidad, S.S. More, L. Kachuri, J.S. Witte, L. Delemotte, K.M. Giacomini, and W. Coyote-Maestas. (2023). The full spectrum of OCT1 (SLC22A1) mutations bridges transporter biophysics to drug pharmacogenomics. bioRxiv.

Yee, S.W., D. Buitrago, A. Stecula, H.X. Ngo, H.C. Chien, L. Zou, M.L. Koleske, and K.M. Giacomini. (2020). Deorphaning a solute carrier 22 family member, SLC22A15, through functional genomic studies. FASEB J. 34: 15734-15752.

Yi, Y., H. Zhang, M. Chen, B. Chen, Y. Chen, P. Li, H. Zhou, Z. Ma, and H. Jiang. (2023). Inhibition of multiple uptake transporters in cardiomyocytes/mitochondria alleviates doxorubicin-induced cardiotoxicity. Chem Biol Interact 382: 110627. [Epub: Ahead of Print]

Yin, Y., X. He, P. Szewczyk, T. Nguyen, and G. Chang. (2006). Structure of the multidrug transporter EmrD from Escherichia coli. Science 312: 741-744.

Yonezawa, A., S. Masuda, S. Yokoo, T. Katsura, and K. Inui. (2006). Cisplatin and oxaliplatin, but not carboplatin and nedaplatin, are substrates for human organic cation transporters (SLC22A1-3 and multidrug and toxin extrusion family). J Pharmacol Exp Ther 319: 879-886.

Yong, Z., Z. Kotur, and A.D. Glass. (2010). Characterization of an intact two-component high-affinity nitrate transporter from Arabidopsis roots. Plant J. 63: 739-748.

Yoshida, K., Y. Yamamoto, K. Omae, M. Yamamoto, and Y. Fujita. (2002). Identification of two myo-inositol transporter genes of Bacillus subtilis. J. Bacteriol. 184: 983-991.

Young, C.S. and J.T. Beatty. (1998). A topological model of the Rhodobacter capsulatus light-harvesting I complex assembly protein LlaA (previously known as ORF1696). J. Bacteriol. 180: 4742-4745.

Young, K.G., R. Hopkins, B.M. Shields, N.J. Thomas, A.P. McGovern, J.M. Dennis, and. (2023). Recent UK type 2 diabetes treatment guidance represents a near whole population indication for SGLT2-inhibitor therapy. Cardiovasc Diabetol 22: 302.

Yousefzadeh, N., S. Jeddi, M. Zarkesh, K. Kashfi, and A. Ghasemi. (2023). Altered sialin mRNA gene expression in type 2 diabetic male Wistar rats: implications for nitric oxide deficiency. Sci Rep 13: 4013.

Yu, J., D. Bhatnagar, and T.E. Cleveland. (2004). Completed sequence of aflatoxin pathway gene cluster in Aspergillus parasiticus. FEBS Lett. 564: 126-130.

Yu, J., P.K. Chang, K.C. Ehrlich, J.W. Cary, D. Bhatnagar, T.E. Cleveland, G.A. Payne, J.E. Linz, C.P. Woloshuk, and J.W. Bennett. (2004). Clustered pathway genes in aflatoxin biosynthesis. Appl. Environ. Microbiol. 70: 1253-1262.

Yu, M., Y.W. Faan, W.Y. Chung, and J.S. Tsang. (2007). Isolation and characterization of a novel haloacid permease from Burkholderia cepacia MBA4. Appl. Environ. Microbiol. 73: 4874-4880.

Yu, S., A. Vit, S. Devenish, H.K. Mahanty, A. Itzen, R.S. Goody, and W. Blankenfeldt. (2011). Atomic resolution structure of EhpR: phenazine resistance in Enterobacter agglomerans Eh1087 follows principles of bleomycin/mitomycin C resistance in other bacteria. BMC Struct Biol 11: 33.

Yu, W., L. Wang, W.Y. Ren, H.X. Xu, N.N. Wu, D.H. Yu, R.J. Reiter, W.L. Zha, Q.D. Guo, and J. Ren. (2023). SGLT2 inhibitor empagliflozin alleviates cardiac remodeling and contractile anomalies in a FUNDC1-dependent manner in experimental Parkinson''s disease. Acta Pharmacol Sin. [Epub: Ahead of Print]

Yu, Z., H. Wang, and G. You. (2023). The regulation of human organic anion transporter 4 by insulin-like growth factor 1 and protein kinase B signaling. Biochem Pharmacol 115702. [Epub: Ahead of Print]

Yuan, Y., F. Kong, H. Xu, A. Zhu, N. Yan, and C. Yan. (2022). Cryo-EM structure of human glucose transporter GLUT4. Nat Commun 13: 2671.

Yun, Y., P. Guo, J. Zhang, H. You, P. Guo, H. Deng, Y. Hao, L. Zhang, X. Wang, Y.S. Abubakar, J. Zhou, G. Lu, Z. Wang, and W. Zheng. (2020). Flippases play specific but distinct roles in the development, pathogenicity, and secondary metabolism of Fusarium graminearum. Mol Plant Pathol 21: 1307-1321.

Yusuf, I.H., M.E. Shanks, P. Clouston, and R.E. MacLaren. (2018). A splice-site variant in FLVCR1 produces retinitis pigmentosa without posterior column ataxia. Ophthalmic Genet 39: 263-267.

Zada, D., E. Blitz, and L. Appelbaum. (2017). Zebrafish - An emerging model to explore thyroid hormone transporters and psychomotor retardation. Mol. Cell Endocrinol. [Epub: Ahead of Print]

Zähner, D., X. Zhou, S.T. Chancey, J. Pohl, W.M. Shafer, and D.S. Stephens. (2010). Human antimicrobial peptide LL-37 induces MefE/Mel-mediated macrolide resistance in Streptococcus pneumoniae. Antimicrob. Agents Chemother. 54: 3516-3519.

Zakataeva, N.P., E.A. Kutukova, S.V. Gronskiĭ, P.V. Troshin, V.A. Livshits, and V.V. Aleshin. (2006). [Export of metabolites by the proteins of the DMT and RhtB families and its possible role in intercellular communication]. Mikrobiologiia 75: 509-520.

Zakataeva, N.P., S.V. Gronskiy, A.S. Sheremet, E.A. Kutukova, A.E. Novikova, and V.A. Livshits. A new function for the Bacillus PbuE purine base efflux pump: efflux of purine nucleosides. Res. Microbiol. 158(8-9): 659-665.

Zannad, F., J.P. Ferreira, J. Butler, G. Filippatos, J.L. Januzzi, M. Sumin, M. Zwick, M. Saadati, S.J. Pocock, N. Sattar, S.D. Anker, and M. Packer. (2022). Effect of Empagliflozin on Circulating Proteomics in Heart Failure: Mechanistic Insights from the EMPEROR Program. Eur Heart J. [Epub: Ahead of Print]

Zhan, C., S. Wang, Y. Sun, X. Dai, X. Liu, L. Harvey, B. McNeil, Y. Yang, and Z. Bai. (2016). The Pichia pastoris transmembrane protein GT1 is a glycerol transporter and relieves the repression of glycerol on AOX1 expression. FEMS Yeast Res 16:.

Zhang Z., Wang R. and Xie J. (2015). Mycobacterium smegmatis MSMEG_3705 encodes a selective major facilitator superfamily efflux pump with multiple roles. Curr Microbiol. 70(6):801-9.

Zhang, C., X. Wei, G.S. Omenn, and Y. Zhang. (2018). Structure and Protein Interaction-based Gene Ontology Annotations Reveal Likely Functions of Uncharacterized Proteins on Human Chromosome 17. J Proteome Res. [Epub: Ahead of Print]

Zhang, C.C., M.C. Durand, R. Jeanjean, and F. Joset. (1989). Molecular and genetical analysis of the fructose-glucose transport system in the cyanobacterium Synechocystis PCC6803. Mol. Microbiol. 3: 1221-1229.

Zhang, F.X., S.N. Ge, Y.L. Dong, J. Shi, Y.P. Feng, Y. Li, Y.Q. Li, and J.L. Li. (2018). Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems. Prog Neurobiol 171: 72-89.

Zhang, J., X. Xu, Y. Zhao, C. Ren, M. Gu, H. Zhang, P. Wu, Y. Wang, L. Kong, and C. Han. (2023). Target Separation and Potential Anticancer Activity of Withanolide-Based Glucose Transporter Protein 1 Inhibitors from var. J Nat Prod. [Epub: Ahead of Print]

Zhang, L. and L. Xu. (2023). Fgf2 and Ptpn11 play a role in cerebral injury caused by sevoflurane anesthesia. Medicine (Baltimore) 102: e36108.

Zhang, L., Q. Yang, Y. Zhang, X. Li, R. Dong, C. Song, L. Cheng, and H. Zhao. (2020). [Effects of resveratrol and soy isoflavones on learning and memory ability and expression of glucose transporter in aging model rats]. Wei Sheng Yan Jiu 49: 249-253.

Zhang, L., T. Gui, L. Console, M. Scalise, C. Indiveri, S. Hausler, G.A. Kullak-Ublick, Z. Gai, and M. Visentin. (2020). Cholesterol stimulates the cellular uptake of L-carnitine by the carnitine/organic cation transporter novel 2 (OCTN2). J. Biol. Chem. [Epub: Ahead of Print]

Zhang, L., W. Guo, Y. Lu, T. Zhou, Y. Wang, X. Tang, and J. Zhang. (2023). Genome-wide characterization of the inositol transporters gene family in Populus and functional characterization of PtINT1b in response to salt stress. Int J Biol Macromol 228: 197-206.

Zhang, P., P. Azad, D.C. Engelhart, G.G. Haddad, and S.K. Nigam. (2021). SLC22 Transporters in the Fly Renal System Regulate Response to Oxidative Stress In Vivo. Int J Mol Sci 22:.

Zhang, W., S. Wang, F. Yu, J. Tang, L. Yu, H. Wang, and J. Li. (2019). Genome-Wide Identification and Expression Profiling of Sugar Transporter Protein (STP) Family Genes in Cabbage (Brassica oleracea var. capitata L.) Reveals their Involvement in Clubroot Disease Responses. Genes (Basel) 10:.

Zhang, W., Y. Liao, P. Shao, Y. Yang, L. Huang, Z. Du, C. Zhang, Y. Wang, Y. Lin, and J. Zhu. (2024). Integrated analysis of differently expressed microRNAs and mRNAs at different postnatal stages reveals intramuscular fat deposition regulation in goats (Capra hircus). Anim Genet. [Epub: Ahead of Print]

Zhang, X., J. Feng, R. Zhao, H. Cheng, J. Ashraf, Q. Wang, L. Lv, Y. Zhang, G. Song, and D. Zuo. (2023). Functional characterization of the gene reveals its significant role in improving nitrogen use efficiency in. PeerJ 11: e15152.

Zhang, X., K. Garbett, K. Veeraraghavalu, B. Wilburn, R. Gilmore, K. Mirnics, and S.S. Sisodia. (2012). A role for presenilins in autophagy revisited: normal acidification of lysosomes in cells lacking PSEN1 and PSEN2. J. Neurosci. 32: 8633-8648.

Zhang, X.C., Y. Zhao, J. Heng, and D. Jiang. (2015). Energy coupling mechanisms of MFS transporters. Protein. Sci. 24: 1560-1579.

Zhang, Y., Q. Bao, L.A. Gagnon, A. Huletsky, A. Oliver, S. Jin, and T. Langaee. (2010). ampG gene of Pseudomonas aeruginosa and its role in β-lactamase expression. Antimicrob. Agents Chemother. 54: 4772-4779.

Zhang, Z., X. Li, F. Yang, C. Chen, P. Liu, Y. Ren, P. Sun, Z. Wang, Y. You, Y.X. Zeng, and X. Li. (2021). DHHC9-mediated GLUT1 S-palmitoylation promotes glioblastoma glycolysis and tumorigenesis. Nat Commun 12: 5872.

Zhao R., Shin DS., Fiser A. and Goldman ID. (2012). Identification of a functionally critical GXXG motif and its relationship to the folate binding site of the proton-coupled folate transporter (PCFT-SLC46A1). Am J Physiol Cell Physiol. 303(6):C673-81.

Zhao R., Visentin M., Suadicani SO. and Goldman ID. (2013). Inhibition of the proton-coupled folate transporter (PCFT-SLC46A1) by bicarbonate and other anions. Mol Pharmacol. 84(1):95-103.

Zhao, J., Y. Liu, L. Zhu, J. Li, Y. Liu, J. Luo, T. Xie, and D. Chen. (2023). Tumor cell membrane-coated continuous electrochemical sensor for GLUT1 inhibitor screening. J Pharm Anal 13: 673-682.

Zhao, R. and I.D. Goldman. (2007). The molecular identity and characterization of a proton-coupled folate transporter--PCFT; biological ramifications and impact on the activity of pemetrexed. Cancer Metastasis. Rev. 26: 129-139.

Zhao, R., E.S. Unal, D.S. Shin, and I.D. Goldman. (2010). Membrane topological analysis of the proton-coupled folate transporter (PCFT-SLC46A1) by the substituted cysteine accessibility method. Biochemistry 49: 2925-2931.

Zhao, R., M. Najmi, A. Fiser, and I.D. Goldman. (2016). Identification of an Extracellular Gate for the Proton-Coupled Folate Transporter (SLC46A1) by Cysteine Cross-Linking. J. Biol. Chem. [Epub: Ahead of Print]

Zhao, R., M. Najmi, S. Aluri, D.C. Spray, and I.D. Goldman. (2018). Concentrative Transport of Antifolates Mediated by the Proton-Coupled Folate Transporter (SLC46A1); Augmentation by a HEPES Buffer. Mol Pharmacol 93: 208-215.

Zhao, R., N. Diop-Bove, M. Visentin, and I.D. Goldman. (2011). Mechanisms of membrane transport of folates into cells and across epithelia. Annu. Rev. Nutr. 31: 177-201.

Zhao, S., Z. Guo, L. Zhu, J. Fan, B. Yang, W. Chai, H. Sun, F. Feng, Y. Liang, C. Zou, X. Jiang, W. Zhao, J. Lü, and C. Zhang. (2023). [Identification, expression and DNA variation analysis of high affinity nitrate transporter / gene family in ]. Sheng Wu Gong Cheng Xue Bao 39: 2743-2761.

Zheng, H., G. Wisedchaisri, and T. Gonen. (2013). Crystal structure of a nitrate/nitrite exchanger. Nature 497: 647-651.

Zheng, H., J. Taraska, A.J. Merz, and T. Gonen. (2010). The prototypical H+/galactose symporter GalP assembles into functional trimers. J. Mol. Biol. 396: 593-601.

Zhou, H., G. Lei, Y. Chen, M. You, and S. You. (2022). Affects the Temperature Adaptability of a Cosmopolitan Pest by Altering Trehalose Tissue Distribution. Int J Mol Sci 23:.

Zhou, J., E. Fernández, A. Galván, and A.J. Miller. (2000). A high affinity nitrate/nitrite transport system from Chlamydomonas requires two gene products. FEBS Lett. 466: 225-227.

Zhou, W., Y.M. Jiang, H.J. Wang, L.H. Kuang, Z.Q. Hu, H. Shi, M. Shu, and C.M. Wa. (2014). Erythromycin-resistant genes in group A β-haemolytic Streptococci in Chengdu, Southwestern China. Indian J. Med. Microbiol. 32: 290-293.

Zhou, Y., Z. Li, C. Chi, C. Li, M. Yang, and B. Liu. (2023). Identification of Hub Genes and Potential Molecular Pathogenesis in Substantia Nigra in Parkinson''s Disease via Bioinformatics Analysis. Parkinsons Dis 2023: 6755569.

Zhou, Z., L. Ma, J. Zhou, Z. Song, J. Zhang, K. Wang, B. Chen, D. Pan, Z. Li, C. Li, and Y. Shi. (2018). Renal hypouricemia caused by novel compound heterozygous mutations in the SLC22A12 gene: a case report with literature review. BMC Med Genet 19: 142.

Zhu, X., K. Ren, Y.Z. Zeng, Z. Zheng, and G.H. Yi. (2018). Biological function of SPNS2: From zebrafish to human. Mol Immunol 103: 55-62.

Zorzano, A., M. Palacín, and A. Gumà. (2005). Mechanisms regulating GLUT4 glucose transporter expression and glucose transport in skeletal muscle. Acta Physiol Scand 183: 43-58.

2.A.1.1 The Sugar Porter (SP) Family


TC#NameOrganismal TypeExample

Galactose:H+ symporter, GalP. Also transports glucose, xylose, fucose (6-deoxygalactose), 2-deoxygalactose and 2-deoxyglucose) (Henderson and Giddens 1977Henderson et al. 1977; Hernández-Montalvo et al., 2001). Relative substrate affinities of wild-type and mutant forms of the E. coli sugar transporter GalP have been determined by solid-state NMR (Patching et al., 2008).  GalP may exist as a trimer with each subunit having a sugar transporting channel (Zheng et al. 2010).


GalP of E. coli (P0AEP1)


Maltotriose/maltose:H+ symporter, Mal6T or Mal61 (Dietvorst et al. 2005).  The orthologue (90% identical) in Saccharomyces pastorianus (Lager yeast) (Saccharomyces cerevisiae x Saccharomyces eubayanus), MTT1 or Mty1 of 615 aas, has higher affinity for maltotriose than maltose (Magalhães et al. 2016).


MAL6 of Saccharomyces cerevisiae

2.A.1.1.100Probable metabolite transport protein YFL040WFungiYFL040W of Saccharomyces cerevisiae
2.A.1.1.101Probable metabolite transport protein YDR387CFungiYDR387C of Saccharomyces cerevisiae
2.A.1.1.102Plastidic glucose transporter 4 (AtpGlcT)PlantsAt5g16150 of Arabidopsis thaliana
2.A.1.1.103D-xylose-proton symporter-like 3, chloroplasticPlantsAt5g59250 of Arabidopsis thaliana
2.A.1.1.104Myo-inositol transporter 2FungiITR2 of Saccharomyces cerevisiae
2.A.1.1.105Hexose transporter HXT11 (Low-affinity glucose transporter LGT3)FungiHXT11 of Saccharomyces cerevisiae
2.A.1.1.106Probable metabolite transport protein CsbCBacilliCsbC of Bacillus subtilis
2.A.1.1.107Hexose transporter HXT15FungiHXT15 of Saccharomyces cerevisiae

Low-affinity glucose transporter HXT1 of 570 aas and 12 TMSs. Substitutions of equivalent salt bridge-forming residues in Hxt1, Rgt2, and Glut4 are predicted to lock them in an inward-facing conformation but lead to different functional consequences. The salt bridge networks in yeast and human glucose transporters and yeast glucose receptors may play different roles in maintaining their structural and functional integrity (Kim et al. 2023).


HXT1 of Saccharomyces cerevisiae

2.A.1.1.109Hexose transporter HXT14FungiHXT14 of Saccharomyces cerevisiae

General α-glucoside:H+ symporter, Gtr3, Mal11,Mal1T, Mtp1 or Agt1 . (Substrates include trehalose, maltotriose, maltose, turanose, isomaltose, α-methyl-glucoside, maltotriose, palatinose, and melezitose) (Smit et al., 2008).  Maltotriose is transported with higher affinity than maltose (Magalhães et al. 2016).


AGT1 of Saccharomyces cerevisiae

2.A.1.1.110Hexose transporter HXT13FungiHXT13 of Saccharomyces cerevisiae

High-affinity glucose transporter HXT2.  Asp340 and Asn331 in part determine the high glucose affinity (Kasahara et al. 2007; Kasahara and Kasahara 2010).


HXT2 of Saccharomyces cerevisiae

2.A.1.1.112High-affinity glucose transporter Ght1 (Hexose transporter 1)YeastGht1 of Schizosaccharomyces pombe

Putative metabolite transport protein YyaJ


YyaJ of Bacillus subtilis


Putative metabolite transport protein YaaU


YaaU of Escherichia coli


Putative metabolite transport protein YdjK


YdjK of Escherichia coli


Arabinose/xylose transporter, AraE (Wang et al. 2013).


AraE of Coynebacterium glutamicum


Glucose transporter Rco-3 or MoST1. MoST1 plays a specific role in conidiation and mycelial melanization which is not shared by other hexose transporter family members in M. oryzae (Saitoh et al. 2013).


MoST1 of Magnaporthe oryzae


MFS porter of 435 aas


MFS porter of Sulfolobus solfataricus


The galacturonic acid (galacturonate) uptake porter, GatA, of 518 aas and 12 TMSs (Sloothaak et al. 2014).


GatA of Aspergillus niger


Glucose uniporter, Glut3 (also transports dehydro-ascorbate; Maulén et al., 2003). Down-regulated in the brains of Alzheimer's disease patients (Liu et al., 2008b).  The structure of the human orthologue with D-glucose bound was solved at 1.5 Å resolution in the outward occluded conformation (Deng et al. 2015).  Sugars are predominantly coordinated by polar residues in the C-terminal domain. The conformational transition from the outward-open to the outward-occluded states entails a prominent local rearrangement of the extracellular part of  TMS 7. Comparison of the outward-facing GLUT3 structures with inward-open GLUT1 provides insight into the alternating access cycle for GLUTs, whereby the C-terminal domain provides the primary substrate-binding site and the N-terminal domain undergoes rigid-body rotation with respect to the C-terminal domain (Deng et al. 2015). Glut3 is involved in several disease states in humans (Lechermeier et al. 2019). Resveratrol and soy isoflavones alone and in combination improve the learning and memory of aging rats. The mechanism may be related to up-regulating the expression of GLUT1 and GLUT3 genes and proteins in the hippocampus (Zhang et al. 2020).


Gtr3 (Glut3) of Rattus norvegicus (rat)


Major myo-inositol transporter, IolT1, of 456 aas (Kröger et al. 2010).


IolT1 of Samonella enterica


Minor myo-inositol transporter, IolT2, of 478 aas (Kröger et al. 2010).


IolT2 of Salmonella enterica


Sorbitol (glucitol):H+ co-transporter, SOT2 (Km for sorbitol of 0.81 mM) of 491 aas and 12 TMSs (Gao et al. 2003). SOT2 of Prunus cerasus is mainly expressed only early in fruit development and not in leaves (Gao et al. 2003).


SOT2 of Pyrus pyrifolia (Chinese pear) (Pyrus serotina)


Sorbitol (D-Glucitol):H+ co-transporter, SOT1 (Km for sorbitol of 0.64 mM) of 509 aas and 12 TMSs (Gao et al. 2003). SOT1 of P. cerasus is expressed throughout fruit development, but especially when growth and sorbitol accumulation rates are highest. In leaves, PcSOT1 expression is highest in young, expanding tissues, but substantially less in mature leaves (Gao et al. 2003).


SOT1 of Prunus salicina


The high affinity sugar:H+ symporter (sugar uptake) porter of 514 aas and 12 TMSs, STP10. It transports glucose, galactose and mannose, and is therefore a hexose transporter (Rottmann et al. 2016). The 2.4 Å structure with glucose bound has been solved, explaining high affinity sugar recognition (Paulsen et al. 2019). The results suggest a proton donor/acceptor pair that links sugar transport to proton translocation. It contains a Lid domain, conserved in all sugar transport proteins, that locks the mobile transmembrane domains through a disulfide bridge, and creates a protected environment which allows efficient coupling of the proton gradient to drive sugar uptake (Paulsen et al. 2019).

STP10 of Arabidopsis thaliana


Glycerol:H+ symporter of 530 aas and 12 TMSs, GT1.  It is essnetial for the glycerol repression of the alcohol oxidase 1 (AOX1 gene (Zhan et al. 2016), and plays a role in glycerol and methanol metabolism in Pichia pastoris (Li et al. 2017).


GT1 of Komagataella pastoris (Yeast) (Pichia pastoris)


Myo inositol uptake porter of 574 aas and 12 TMSs, Fst1.  Also takes up the polyketide mycotoxin produced by Fusarium verticillioides during the colonization of maize kernels, Fumonisin B1 (FB1).  The activity was demonstrated with the orthologue in Weissella verticillioides (Niu et al. 2016). 

Fst1 of Weissella confusa


Hexose:proton symporter of 525 aas and 12 TMSs, Hxt5. Takes up D-glucose, D-fructose, D-xylose, D-mannose, D-galactose with decreasing affinity in this order (Rani et al. 2016).

Hxt5 of Piriformospora indica


Facilitative (Na+-independent) glucose-specific transporter (Km = 3 mM) of 486 aas and 12 TMSs, HT1; inhibited by cytochalasin B and localized to the midgut (Price et al. 2007).

HT1 of Nilaparvata lugens (Brown planthopper)


High-capacity facilitative transporter for trehalose, TRET1, required to induce anhydrobiosis. Anhydrobiotic larvae can survive almost complete dehydration. Does not transport maltose, sucrose or lactose. Transports trehalose synthesized in the fat body and incorporates trehalose into other tissues that require a carbon source, thereby regulating trehalose levels in the hemolymph (Kikawada et al. 2007; Kanamori et al. 2010).  70% identical to the Drosophila homologue, TC# 2.a.1.1.99.

TRET1 of Polypedilum vanderplanki (Sleeping chironomid)


Fructose uniporter, GLUT5.  The proteins from rat and cow have been crystalized and their structures have been determined in the open outward- and open inward-facing conformations, respectively. On the basis of comparisons of the inward-facing structures of GLUT5 and human GLUT1, a ubiquitous glucose transporter, a single point mutation proved to be enough to switch the substrate-binding preference from fructose to glucose. A comparison of the substrate-free structures of GLUT5 with occluded substrate-bound structures of E. coli XylE suggested that, in addition to a global rocker-switch-like re-orientation of the bundles, local asymmetric rearrangements of carboxy-terminal transmembrane bundle helices, TM7 and TM10, underlie a 'gated-pore' transport mechanism (Nomura et al. 2015).  GLUT5 is preferentially used for fructose uptake under (near) anoxic glycolysis to avoid feedback inhibition of phosphofructokinase (Park et al. 2017). Residues involved in fructose recognition have been identified (Ebert et al. 2017). Glucose (Glut-1 and 3) and fructose (Glut-2 and 5) transporter expression and regulation in the hummingbird occur independently of each other (Ali et al. 2020). Complex plastic mechanisms allow adaptation to environmental changes (Huang et al. 2023). C-3 modified 2,5-anhydromannitol (2,5-AM) compounds are inhibitory D-fructose analogues (Rana et al. 2023).  Discrimination of GLUTs by fructose isomers enables simultaneous screening of GLUT5 and GLUT2 activities in live cells (Gora et al. 2023).



SLC2A5 of Homo sapiens


Glucose transporter 1, GLUT1 or Slc2A1 of 491 aas and 12 TMSs.  Expression occurs in the mesodermal region of Xenopus embryos, especially in the dorsal blastopore lip at the gastrula stage.  It is an important player during gastrulation cell movement (Suzawa et al. 2007). This system is required for hepatocellular carcinoma proliferation and metastasis (Fang et al. 2021).

GLUT1 of Xenopus laevis (African clawed frog)


Myo-inositol-specific uptake transporter, ITR1 of 509 aas and 12 TMSs.  The Km for myo-inositol is about 1 mM; glucose and other inositols are apparently not transported (Cushion et al. 2016).

ITR1 of Pneumocystis carinii


Bloom1 of 524 aas and 12 TMSs in a 6 + 6 arrangement. Mutations in the encoding gene give rise to shiny soybean seads with increased amounts of oil (Zhang et al. 2018). This protein is 50% identical to the sorbitol transporter of Prunus salicina (TC# 2.A.1.1.123).

Bloom1 of Glycine max (Soybean) (Glycine hispida) (Glycine soja)


Facilitative glucose transporter, GLUT2 of 503 aas and 12 TMSs.  Evidence suggests that the blunt snout bream is able to regulate its ability to metabolize glucose by improving GLUT2, GK, and PK expression levels (Liang et al. 2018).  The ortholog in grass carp (Ctenopharyngodon idellus) is exactly the same size and 98% identical throughout its length. It is found in the anterior and mid intestine as well as the liver (Liang et al. 2020).

GLUT2 of Megalobrama amblycephala (Chinese blunt snout bream) (Brema carp)


Sugar (mannose, fructose, glucose, galactose xylose) transporter of 521 aas and 12 TMSs, STP2 (Liu et al. 2018).

STP2 of Manihot esculenta (Cassava) (Jatropha manihot)


Galactose-specific uptake porter of 515 aas and 12 TMSs, STP16 (Liu et al. 2018).

STP16 of Manihot esculenta (Cassava) (Jatropha manihot)


Monosaccharide uptake porter of 529 aas and 12 TMSs, STP7. Transports mannose, galactose, glucose and fructose, but not xylose (Liu et al. 2018).

STP7 of Manihot esculenta (Cassava) (Jatropha manihot)


Glycerol:H+ symporter,WaStl1, of 561 aas and 12 TMSs. WaStl1 is a concentrative glycerol-H+ symporter with twice the affinity of S. cerevisiae. It is repressed by glucose and derepressed/induced by glycerol. This yeast, aerobically growing on glycerol, was found to produce ethanol, providing a redox escape to compensate the redox imbalance at the level of cyanide-resistant respiration (CRR) and glycerol 3P shuttle (da Cunha et al. 2019).

Glycerol porter of Wickerhamomyces anomalus


Maltose permease, HPMAL2, of 582 aas and 12 TMSs in a 1 + 5 + 6 TMS arrangement.  Expression of both of the adjacent HPMAL1 and HPMAL2 genes is coordinately regulated, repressed by glucose, and induced by maltose (Viigand et al. 2005).

MAL2 of Pichia angusta (Yeast) (Hansenula polymorpha)


Glut3 or Slc2a3a of 541 aas and 12 TMSs. Transcript analysis of zebrafish GLUT3 genes, slc2a3a and slc2a3b, have define overlapping as well as distinct expression domains in the central nervous system (Lechermeier et al. 2019).

Glut3 of Danio rerio


Hexose:H+ symporter of 534 aas and 12 TMSs.  Substrate accumulation can be up to 1500-fold;  one proton  is symporter per hexose taken up. Helices I, V, VII and XI interact with the sugar during translocation and line the transport path through the membrane (Tanner 2000).


Hup1 of Chlorella kessleri


Cellodextrin transporter, CtA or CDT-1, of 535 aas and 12 TMSs.  It transports cellobiose, cellotriose, cellotetraose and cellopeptaose, and its synthesis is induced by degradation products of cellulose (Lin et al., Feb. 2020, Identification and Characterization of a Cellodextrin Transporter in Aspergillus niger). It is 37% identical to the N crassa protein of the same specificity (TC# 2.A.1.1.82).

CtA of  Aspergillus niger


Lactose permease of 533 aas and 12 TMSs; 45% identical to 2.A.1.1.140 (Havukainen et al. 2020).

Lactose permease of Aspergillus nidulans


MFS-type cellodextrin transporter, CdtG, of 538 aas and 12 TMSs (Havukainen et al. 2020).

CdtG of Penicillium sp. 2HH


Facilitative glucose transporter 4, GLUT4, of 505 aas and 12 TMSs. MaGLUT4 is mainly distributed in muscle. Changes in the insulin, mRNA, and protein levels of MaGUT4 lagged far behind changes in blood glucose levels. This delay in insulin level changes and GLUT4 activation might be the reason for glucose intolerance of this fish species (Liang et al. 2020).

GLUT4 of Megalobrama amblycephala (Chinese blunt snout bream) (Brema carp)


Plant MFS porter of 521 aas and 12 TMSs. This system affects nutrient minerals concentrations in wheat grains and showed a pleiotropic effect on Ca2+, K+, Mg2+, Mn2+, and Sulfur (Alomari et al. 2021). In view of its association with sugar uptake porters, we suggest that it is a sugar transporter, and sugar uptake increases the energy of the grains so as to stimulate elemental ion uptake.

MFS porter of Triticum aestivum (bread wheat)


MFS-type sugar/inositol transporter of 510 aas and 12 TMSs. An orthologous system has been shown to be a highly specific L-arabinose transporter from Trichoderma reesei (Havukainen et al. 2021). Considering the high affinity for L-arabinose and low inhibition by D-glucose or D-xylose, Trire2_104072 could serve as a good candidate for improving the existing pentose-utilizing yeast strains (Havukainen et al. 2021).

L-Arabinose transporter of Penicillium sp.


MFS glucose transporter, Mfs1, of 550 aas and 12 TMSs. It is required for sugar transport, oxidative stress resistance, and pathogenicity of Colletotrichum gloeosporioides in Hevea brasiliensis (Liu et al. 2021). C. gloeosporioides is the causal agent of anthracnose in various plant species.

Mfs1 of Colletotrichum gloeosporioides


Glucose transporter 1, GLUT1, of 500 aas and 12 TMSs. EgGLUT1 Is crucial for the viability of Echinococcus granulosus sensu stricto metacestode and may be a new therapeutic target (Amahong et al. 2021).

GLUT1 of Echinococcus granulosus


High affinity hexose transporter, HxtA of 531 aas and 12 TMSs. HxtA is induced in vegetative hyphae upon starvation and in ascogenous hyphae during cleistothecium formation (Wei et al. 2004).

HxtA of Emericella nidulans (Aspergillus nidulans)

2.A.1.1.15Putative sugar transporterArchaeaPorter of Sulfolobus solfataricus

Hexose transporter-like protein, GCR1, of 541 aas and 12 TMSs. Substrates include glucose, mannose and fructose. It functions in catabolite repression (as does Snf3p in S. cerevisiae (TC# 2.A.1.1.18)) of peroxisome biogenesis and of peroxisomal enzymes (Stasyk et al. 2004).

GCR1 of Ogataea polymorpha (Hansenula polymorpha)


Facilitated trehalose transporter, Tret1-like, of 485 aas and 12 TMSs in a 6 + 6 TMS arrangement. Trehalose is the main blood sugar in insects and plays an important role in energy metabolism and stress resistance. Plutella xylostella (L.) is an agricultural pest worldwide. Tret1-like was cloned, knoched out and studied (Zhou et al. 2022). It was found that expression of the gene encoding PxTret1-like was affected by ambient temperature. A knockout mutation of PxTret1-like was generated, and the trehalose content and trehalase activity of the mutant increased at different developmental stages. The trehalose content increased in the fat body of the fourth-instar and decreased in the hemolymph. There was no significant change in glucose in the fat body and hemolymph. Mutant deletion strains of P. xylostella showed a significantly reduced survival rate, fecundity and ability to withstand extreme temperatures. Thus, PxTret1-like could affect the development, reproduction and temperature adaptability of P. xylostella by regulating the trehalose content in the fat body and hemolymph (Zhou et al. 2022).

Tret1-like transporter of Plutella xylostella


INT7 of 504 aas and 12 TMSs in a 6 + 6 TMS pattern. There are nine INT homologues in Populus trichocarpa, all presumed to transport inositor, and they are involved in stress responses (Zhang et al. 2023).


INT7 of Populus alba x Populus glandulosa


Sugar transporter of 529 aas and 12 TMSs.

Sugar transporter of Planoprotostelium fungivorum


Solute carrier family 2, facilitated glucose transporter member 8 of 509 aas and 12 TMSs. Symbiotic cnidarians such as corals and anemones form highly productive and biodiverse coral reef ecosystems in nutrient-poor ocean environments, a phenomenon known as Darwin's paradox (Cui et al. 2023). Using the sea anemone Aiptasia, we show that during symbiosis, the increased availability of glucose and the presence of the algae jointly induce the coordinated up-regulation and relocalization of glucose and ammonium transporters. These molecular responses are critical to support symbiont functioning and organism-wide nitrogen assimilation through glutamine synthetase/glutamate synthase-mediated amino acid biosynthesis (Cui et al. 2023). 

Glucose transporter of Exaiptasia diaphana


Sugar transporter ERD6-like 4 of 496 aas and 12 TMSs. Vacuolar sugar transporter EARLY RESPONSE TO DEHYDRATION 6-LIKE4 affects fructose signaling and plant growth (Khan et al. 2023).

ERD6-like 4 of Triticum aestivum


Mannosyltransferase  with 3 C-terminal TMSs in a 2 + 1 TMS arrangement. It is involved in N-Glycan biosynthesis and displays an unexpected minimal cellulose-synthase-like fold (Gandini et al. 2020).

MT of Pyrobaculum calidifontis


Putative sugar uptake transporter of 456 aas and 18 TMSs in a 6 + 6 + 6 TMS arrangement.  This protein has an N-terminal 6 TMSs that are not related to the MFS transporters, but the last 12 TMSs are homologous to members of MFS family 2.A.1.1. The N-terminal 6 TMSs are not related to sequences of the MFS but are homologous to members of the

MFS transporter of Alistipes sp. HGB5



Low-affinity hexose (glucose, fructose, mannose, 2-deoxyglucose) uniporter.  The evolution of hexose transporters in kinetoplastid protozoans has been studied (Pereira and Silber 2012).


Gtr2 (D2) of Leishmania donovani

2.A.1.1.17Glucose transporterProtozoaTh2A of Trypanosoma brucei

Glucose/mannose/fructose transporter and high affinity sensor, Snf3p, (regulates glucose transport via other systems).  Residues involved in ligand preference are similar to those involved in transport (Dietvorst et al. 2010).  Snf3p in Candida glabrata is essential for growth in low glucose media but not high glucose media, and plays a role in the induction of severall hexose transporters (Ng et al. 2015).


Snf3p of Saccharomyces cerevisiae


Glucose transporter and low affinity sensor, Rgt2p (regulates glucose transport in conjunction with Snf3p). Rgt2 generates an intracellular signal in response to glucose that leads to inhibition of the Rgt1 transcriptional repressor and consequently to derepression of HXT genes encoding glucose transporters. They have unusually long C-terminal tails that bind to Mth1 and Std1, paralogous proteins that regulate the function of the Rgt1 transcription factor. Scharff-Poulsen et al. 2018 showed that the C-terminal tail of Rgt2 is not responsible for its inability to transport glucose. RGT2 mutations that cause constitutive signal generation alter evolutionarily-conserved amino acids in the transmembrane spanning regions involved in maintaining an outward-facing conformation or the substrate binding site. These mutations may cause Rgt2 to adopt inward-facing or occluded conformations that generate the glucose signal. The cytoplasmic C-terminal domains of the yeast cell surface receptors Rgt2 and Snf3 play multiple roles in glucose sensing and signaling (Kim et al. 2024).


Rgt2p of Saccharomyces cerevisiae


Arabinose (xylose; galactose):H+ symporter, AraE (low affinity high capacity) (Khlebnikov et al. 2001).


AraE of E. coli (P0AE24)

2.A.1.1.20Myoinositol:H+ symporter, MITProtozoaMIT of Leishmania donovani; most similar to ITRI of Saccharomyces cerevisiae
2.A.1.1.21Hexose:H+ symporter, Ght2 (Glucose > Fructose)YeastGht2 of Schizosaccharomyces pombe
2.A.1.1.22Hexose:H+ symporter, Ght6 (Fructose > Glucose)YeastGht6 of Schizosaccharomyces pombe
2.A.1.1.23Gluconate:H+ symporter, Ght3YeastGht3 of Schizosaccharomyces pombe

Hexose (Glucose and Fructose) transporter, PfHT1 of 504 aas and 12 TMSs. This is the only hexose transporter, and it is found in the plasma membrane. It is an antimalarial drug target (Meier et al. 2018; Wunderlich 2022).


PfHT1 of Plasmodium falciparum


Myoinositol:H+ symporter, HMIT (also transport other inositols including scyllo-, muco- and chiro-, but not allo-inositol) (Aouameur et al., 2007). Expressed in the Golgi of the hippocampus and cortex. May also transport inositoltriphosphate (Di Daniel et al., 2009). Interacts directly with γ-secretase (9.B.47.1.1) to regulate its activity and the production of Abeta production, important in Alzheimer's disease (Teranishi et al. 2015).


SLC2A13 of Homo sapiens


Major myoinositol:H+ symporter, IolT, of 473 aas and 12 TMSs in a 6 + 6 TMS pattern (Yoshida et al. 2002).


IolT (YdjK) of Bacillus subtilis


Minor, low affinity myoinositol:H+ symporter, IolF, of 438 aas and 12 TMSs (Yoshida et al. 2002).


IolF of Bacillus subtilis


The erythrocyte/brain hexose facilitator, glucose transporter-1, Gtr1. SLC2a1 or Glut1. Transports D-glucose, dehydroascorbate, arsenite and the flavonone, quercetin, via one pathway and water via a distinct channel. Sugar transport has been suggested to function via a sliding mechanism involving several sugar binding sites (Cunningham et al., 2006). Glut1 is the receptor for human T-cell leukemia virus (HTLV)) (Manel et al., 2003). The orientation of the 12 TMSs and the conformation of the exofacial glucose binding site of GLUT1 have been proposed (Mueckler and Makepeace 2004). It is regulated by stomatin (TC# 8.A.21) to take up dehydroascorbate (Montel-Hagen et al., 2008). Mutations cause Glut1 deficiency syndrome, a human encephalopathy that results from decreased glucose flux through the blood brain barrier (Pascual et al., 2008).  Mueckler and Makepeace (2009) have presented a model of the exofacial substrate-binding site and helical folding of Glut1. Glut1, 2, 4 and 9 are functional both in the plasma membrane and the endoplasmic reticulum (Takanaga and Frommer, 2010). Glut1 is down-regulated in the brains of Alzheimer's disease patients (Liu et al., 2008b). Metabolic stress rapidly stimulates blood-brain barrier endothelial cell sugar transport by acute up-regulation of plasma membrane GLUT1 levels, possibly involving an AMP-activated kinase activity (Cura and Carruthers, 2010). Serves as a receptor for neuropilin-1 (923aas; 2 TMSs; O14786) and heparan sulfate proteoglycans (HSPGs) (Hoshino, 2012). Glut1 has a nucleotide binding site, and nucleotide binding affects transport activity (Yao and Bajjalieh 2009).  The protein serves as a receptor for dermatin and β-adducin which help link the spectrin-actin junctional complex to the erythrocyte plasma membrane (Khan et al. 2008).  May play a role in paroxysmal dyskinesias (Erro et al. 2017). GLUT1 mediates infection of CD4+ lymphocytes by human T cell leukemia virus type 1 (Jin et al. 2006). Mutations in disordered regions can cause disease by introducing dileucine motifs, For example, mutations that are causative of GLUT1 deficiency syndrome are of this type, and the mutated protein mislocalizes to intracellular compartments (Meyer et al. 2018). Glucose transits along a transmembrane pathway through significant rotational motions while maintaining hydrogen bonds with the protein (Galochkina et al. 2019). It is phosphoryated by protein kinase C-B (TC# 8.A.104.1.4) (Lee et al. 2015). GLUT1-mediated exchange of fluorosugars has been studied (Shishmarev et al. 2018). Resveratrol and soy isoflavones alone and in combination improve the learning and memory of aging rats. The mechanism may be related to up-regulating the expression of GLUT1 and GLUT3 genes in the hippocampus (Zhang et al. 2020). The pore diameters of the transmembrane glucose transporters of all Class I GLUT proteins are constricted upon depletion of unsaturated fatty acids in the membranes (Weijers 2020). Diclofenac inhibits tumor cell glycolysis and growth by decreasing GLUT1 expression (Yang et al. 2021). Almost the entire populations of Glut1 and three other transmembrane proteins are immobilized by either the incorporation within large multiprotein complexes or entrapment within the protein network of the cortical spectrin cytoskeleton (Kodippili et al. 2020). This system is required for hepatocellular carcinoma proliferation and metastasis (Fang et al. 2021). The main triggers FoR activation of transport are located within the solvent accessible linker regions in the extramembranous zones (Gonzalez-Resines et al. 2021). DHHC9-mediated GLUT1 S-palmitoylation is requuired for plasma membrane localization and promotes glioblastoma glycolysis and tumorigenesis (Zhang et al. 2021). An ancient family of arrestin-fold proteins, termed alpha-arrestins, have conserved roles in regulating nutrient transporter trafficking and cellular metabolism as adaptor proteins. One alpha-arrestin, TXNIP (thioredoxin-interacting protein), is known to regulate myocardial glucose uptake, but the in vivo role of the related alpha-arrestin, ARRDC4 (arrestin domain-containing protein 4), was unknown. Interactions of ARRDC4 with GLUT1 prove to mediate metabolic stress in the ischemic heart (Nakayama et al. 2022). Mercury (Hg2+) decreased membrane deformability, impairing RBC capacity to deal with the shear forces in the circulation, increasing membrane fragmentation, and affecting transport (Notariale et al. 2022). GLUT-1 and GLUT-3 play important roles in the development of some types of malignant tumors, including glioblastoma, and expression of both is regulated by miRNAs (Beylerli et al. 2022). Glucose uptake inhibitors via Glut1 are potential anticancer agents (Hung et al. 2022). GLUT1 deficiency syndrome (GLUT1DS1) is a rare genetic metabolic disease, characterized by infantile-onset epileptic encephalopathy, global developmental delay, progressive microcephaly, and movement disorders (e.g., spasticity and dystonia) (Mauri et al. 2022). It is caused by heterozygous mutations in the SLC2A1 gene, which encodes the GLUT1 protein, a glucose transporter across the blood-brain barrier (BBB). Most commonly, these variants (~2 dozen) arise de novo, resulting in sporadic cases, although several familial cases with AD inheritance pattern have been described (Mauri et al. 2022). Fluoride exposure affects the expression of glucose transporters (GLUT1 and 3) and ATP synthesis (Chen et al. 2023). GLUT1 is necessary for the flexor digitorum brevis (FDB) to survive hypoxia, but overexpression of GLUT1 was insufficient to rescue other skeletal muscles from hypoxic damage (Amorese et al. 2023). The role of GLUT inhibitors, micro-RNAs, and long non-coding RNAs that aid in inhibiting glucose uptake by cancer cells have been discussed as potential theraputics (Chamarthy and Mekala 2023). GLUT1 overexpression in tumor cells is a potential target for drug therapy (Zhao et al. 2023). HSP90B1-mediated plasma membrane localization of GLUT1 promotes radioresistance of glioblastomas (Li et al. 2023).  The core genes (Fgf2, Pdgfra, Ptpn11, Slc2a1) are highly expressed in sevoflurane anesthesia brain tissue samples. The 4 core genes (Fgf2, Pdgfra, Ptpn11, and Slc2a1) are associated with neurodegenerative diseases, brain injuries, memory disorders, cognitive disorders, neurotoxicity, drug-induced abnormalities, neurological disorders, developmental disorders, and intellectual disabilities. Fgf2 and Ptpn11 are highly expressed in brain tissue after sevoflurane anesthesia, the higher the expression level of Fgf2 and Ptpn11, the worse the prognosis (Zhang and Xu 2023). Target separation and potential anticancer activity of withanolide-based glucose transporter protein 1 inhibitors from Physalis angulata var. villosa have been evaluated (Zhang et al. 2023).  PIGT is a subunit of the glycosylphosphatidylinositol transamidase which is involved in tumorigenesis and invasiveness.  PIGT promotes cell growth, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking (Tan et al. 2024).  PDGF-stimulated glucose uptake via Glut1 has been reported to be dependent on receptor/transporter endocytosis (Tsutsumi et al. 2024).


SLC2A1 of Homo sapiens


Glucosamine/glucose/fructose uniporter, Glut-2, Glut2 or ATG9A; it may also transport dehydroascorbate (Mardones et al., 2011Maulén et al., 2003), and cotransports water against an osmotic gradient (Naftalin, 2008).  Mutations may give rise to the rare autosomal recessive Fanconi-Bickel syndrome (Batool et al. 2019). It mediates intestinal transport of quercetrin (Li et al. 2020) and can transport the drug gastrodin, a seditive with a strcture of a phenolic glucoside (Huang et al. 2023). It also functions in autophagy. The cryoEM structure of the human ATG9A isoform at 2.9-Å resolution has been solved (Guardia et al. 2020). The structure reveals a fold with a homotrimeric domain-swapped architecture, multiple membrane spans, and a network of branched cavities, consistent with ATG9A being a membrane transporter. Mutational analyses support a role for the cavities in the functions of ATG9A. Structure-guided molecular simulations predict that ATG9A causes membrane bending, explaining the localization of this protein to small vesicles and highly curved edges of growing autophagosomes (Guardia et al. 2020). Both GLUT2 and GLUT3 have been expressed in yeast and exhibit most of the characteristics of the proteins expressed in humans (Schmidl et al. 2020). Autophagy is a highly conserved pathway that the cell uses to maintain homeostasis, degrade damaged organelles, combat invading pathogens, and survive pathological conditions. A set of proteins, called ATG proteins, comprise the core autophagy machinery and work together in a defined hierarchy. ATG9A vesicles are at the heart of autophagy, as they control the rapid de novo synthesis of an organelle called the phagophore. ATG9A is present in different membrane compartments (van Vliet et al. 2023).  Metformin increases the uptake of glucose into the gut from the circulation in high-fat diet-fed male mice, which is enhanced by a reduction in whole-body Slc2a2 expression (Morrice et al. 2023).



SLC2A2 of Homo sapiens


Xylose (xylopyranose):H+ symporter of 491 aas and 12 TMSs (Wambo et al. 2017).  Also transports and binds D-glucose and 6-bromo-6-deoxy-D-glucose.  The 3-d structure is known in three conformers, outward occluded, inward occluded and inward open (Sun et al. 2012: Quistgaard et al. 2013).  Most of the sugar-binding residues are conserved with the human Glut-1, 2, 3 and 4 homologues.  The coalescence of intramolecular tunnels and cavities has been postulated to account for facilitated diffusion of sugars (Cunningham and Naftalin 2014). Protonation of a conserved aspartate triggers a conformational transition from the outward-facing to the inward-facing state. This transition only occurs in the presence of substrate xylose, while the inhibitor glucose locks the transporter in the outward-facing state (Jia et al. 2020).


XylE of E. coli (P0AGF4)


Low affinity, constitutive, glucose (hexose; xylose) uniporter, Hxt4 (LGT1; Rag1) (also transports arsenic trioxide [As(OH)3] as do Hxtl, 3, 5, 7 and 9) (Liu et al., 2004).  The Kluyveromyces lactis ortholog is 73% identical and is similarly regulated (Rolland et al. 2006). Key residues for efficient glucose transport by the hexose transporter CgHxt4 in the high sugar fermentation yeast Candida glycerinogenes.have been identified (Qiao et al. 2021).


Hxt4 of Saccharomyces cerevisiae


High affinity, glucose-repressible, glucose (hexose) uniporter (Hxt6/Hxt7). Asn331 and hydrophobic residue side chains in TMS5 determine substrate affinity (Kasahara et al., 2011; Kasahara and Kasahara 2010).  Also transports xylose (Wang et al. 2013).


Hxt6/Hxt7 of Saccharomyces cerevisiae
Hxt6 (P39003)

2.A.1.1.32Glucose/fructose:H+ symporter, GlcP (Zhang et al., 1989)BacteriaGlcP of Synechocystis sp. (P15729)
2.A.1.1.33Fructose:H+ symporter, Frt1 (Diezemann and Boles, 2003)YeastFrt1 of Kluyveromyces lactis (CAC79614)
2.A.1.1.34The broad specificity sugar/sugar alcohol (myo-inositol, glycerol, ribose, sorbitol, mannitol, xylitol, erythritol, etc) H+ symporter, AtPLT5 (transports a wide range of hexoses, pentoses, tetroses, sugar alcohols and a sugar acid, but not disaccharides) (Reinders et al., 2005) (expressed in roots, leaves and floral organs) (Klepek et al., 2004)PlantsAtPLT5 of Arabidopsis thaliana (Q8VZ80)
2.A.1.1.35The major glucose (or 2-deoxyglucose) uptake transporter, GlcP (van Wezel et al., 2005)BacteriaGlcP of Streptomyces coelicolor (Q7BEC4)

The low affinity, glucose-inducible glucose transporter, MstE (Forment et al., 2006)


MstE of Aspergillus nidulans (Q400D8)

2.A.1.1.37The glucose/fructose facilitator, Glut7 (SLC2A7) (a single mutation, I314V, results in loss of fructose transport but retention of glucose transport (Manolescu et al., 2005)AnimalsSLC2A7 of Homo sapiens
2.A.1.1.38The glycerol:H+ symporter, Stl1p (Ferreira et al., 2005)YeastStl1p of Saccharomyces cerevisiae (NP_010825)
2.A.1.1.39The high affinity glucose transporter, Hgt1 (Baruffini et al., 2006)YeastHgt1 of Kluyveromyces lactis (P49374)
2.A.1.1.4Glucose uniporterBacteriaGlf of Zymomonas mobilis
2.A.1.1.40The xylose facilitator, Xylhp (Nobre et al., 1999)YeastXylhp of Debaryomyces hansenii (AAR06925)
2.A.1.1.41The D-xylose:H+ symporter, XylT (Km=220 μM; inhibited competitively by 6-deoxyglucose (Ki=220 μM), but not by other sugars tested) (Chaillou et al., 1998)BacteriaXylT of Lactobacillus brevis (O52733)
2.A.1.1.42The D-glucose:H+ symporter, GlcP (glucose uptake is inhibited by 2-deoxyglucose, mannose and galactose) (Parche et al., 2006)BacteriaGlcP of Bifidobacterium longum (AAN25419)

The monosaccharide (MST) (glucose > mannose > galactose > fructose):H+ symporter, MST1 (Schussler et al., 2006).


MST1 of Geosiphon pyriformis (A0ZXK6)

2.A.1.1.44The hexose (glucose and fructose but not galactose) transporter (Glut11; SLC2A11) (Scheepers et al., 2005)AnimalsSLC2A11 of Homo sapiens

Vacuolar (tonoplast) glucose transporter1, Vgt1 (important for seed germination and flowering) (Aluri and Büttner, 2007)


Vgt1 of Arabidopsis thaliana (Q8L6Z8)


The blastocyst/testis glucose transporter, Glut8 (Doege et al., 2000) (insulin stimulated in blastocysts) (Carayannopoulos et al., 2000).


Glut8 of Mus musculus (Q9JIF3)


The embryonic liver, kidney, and other tissue uric acid (urate) transporter, Glut9 (SLC2A9) (Wright et al. 2010). Mutations in this transporter cause severe renal hyperuricemia.  It transports hexoses as well as urate, the latter by an electrogenic uniport mechanism.  It's transcription is regulated by a hepatocyte nuclear factor, HNF4α (Prestin et al. 2014).


Glut9 of Mus musculus (Q5ERC7)

2.A.1.1.48The pentose/hexose transporter (sugar transport protein 2), STP2. (Expressed during pollen maturation and early stages of gametophyte development) (Truernit et al., 1999) Plants STP2 of Arabidopsis thaliana (Q9LNV3)
2.A.1.1.49The sink-specific, stress-regulated monosaccharide uptake porter, STP4. (Induced upon wounding or infection with bacteria or fungi; expressed in roots and flowers) (Truernit et al., 1996)PlantsSTP4 of Arabidopsis thaliana (Q39228)
2.A.1.1.5Hexose uniporterYeastHxtO of Saccharomyces cerevisiae

The glucose/fructose:H+ symporter, STP13 (sugar transport protein 13). Expressed in vascular tissues and induced during programmed cell death (Norholm et al., 2006).  Used to combat bacterial infection by competing with them for sugars by phosphorylation of STP13 by the BAK1 receptor kinase (Yamada et al. 2016).


STP13 of Arabidopsis thaliana (Q94AZ2)

2.A.1.1.51Glucose/xylose: H+ symporter, Gsx1 (Leandro et al., 2006)yeastGsx1 of Candida intermedia (Q2MEV7)
2.A.1.1.52The glucose transport protein, GTP1 (Skelly et al., 1994)AnimalsGTP1 of Schistosoma mansoni (Q26579)

Myo-Inositol uptake porter, IolT1 (Km=0.2mM) (Krings et al., 2006).  Can also transport D-glucose (Ikeda et al. 2011).


IolT1 of Corynebacterium glutamicum (Q8NTX0)


Myo-Inositol (Km=0.45mM) uptake porter, IolT2 (Krings et al., 2006).  Can not transport D-glucose (Ikeda et al. 2011).


IolT2 of Corynebacterium glutamicum (Q8NL90)


L-arabinose:proton symporter, AraE (Sa-Nogueira and Ramos, 1997). Also transports xylose, galactose and α-1,5 arabinobiose (Ferreira and Sá-Nogueira, 2010).


AraE of Bacillus subtilis (P96710)

2.A.1.1.56High affinity monosaccharide (KM ≈ 20 µM):H+ symporter, Stp6 (takes up glucose, 3-O-methylglucose, mannose, fructose, galactose and to a lesser extent, xylose and ribulose. (Scholz-Starke et al., 2003)PlantsStp6 of Arabidopsis thaliana (Q9SFG0)

High affinity (15 μM) glucose (monosaccharides including xylose):H+ symporter, MstA (Jørgensen et al., 2007).


MstA of Aspergillus niger


Low affinity glucose:H+ symporter, MstC (Jørgensen et al., 2007).


MstC of Aspergillus niger

2.A.1.1.59The glucose transporter, GLUT10, was originally believed to be responsible for Type 2 diabetes. It is now believed to be responsible for arterial tortuosity, a rare autosomal recessive connective tissue disease (Callewaert et al., 2007). GLUT10 transports glucose and 2-deoxy glucose (Km=0.3 mM), and is inhibited by galactose and phloretin (Coucke et al., 2006). AnimalsSLC2A10 of Homo sapiens

Galactose, glucose uniporter, Gal2. Also transports xylose (Wang et al. 2013).  This transporter has been engineered by mutation (N376F) to transport xylose without being inhibited by glucose or transporting other hexoses (Farwick et al. 2014).  The 3-d structure is known (Wang et al. 2015).


Gal2 of Saccharomyces cerevisiae

2.A.1.1.60The major hexose transporter, Htr1 (mediates the active uptake of hexoses by sugar:H+ symport. Can transport glucose, 3-O-methylglucose, fructose, xylose, mannose, galactose, fucose, 2-deoxyglucose and arabinose. Confers sensitivity to galactose in seedlings. Km=20 uM for glucose) (Stadler et al., 2003; Boorer et al., 1994)PlantsHtr1 of Arabidopsis thaliana (P23586)

High affinity monosaccharide (Km = 25 µM) transporter (takes up glucose, galactose, mannose, xylose and 3-O-methylglucose, but not fructose and ribose), STP11 (expressed in pollen tubes) (Schneidereit et al., 2005).  This protein is also called Sugar Transport Protein (STP).  Expression profiles of homologues in cabbage have been studied (Zhang et al. 2019).


STP11 of Arabidopsis thaliana (Q9FMX3)

2.A.1.1.62High affinity (0.24mM) plasma membrane myoinositol-specific H+ symporter, INT4 (Schneider et al., 2006) PlantsINT4 of Arabidopsis thaliana (O23492)
2.A.1.1.63Low affinity inositol (myoinsoitol (Km = 1 mM), scylloinositol, d-chiroinositol and mucoinositol):H+ symporter (expressed in the anther tapetum, the vasculature, and the leaf mesophyll (Schneider et al., 2007)PlantsINT2 of Arabidopsis thaliana (Q9C757)
2.A.1.1.64The hexose sensor, Hxs1 (believed to be non-transporting) (Stasyk et al., 2008)YeastHxs1 of Hansenula polymorpha (B1PM37)
2.A.1.1.65Glucose permease GlcP (Pimentel-Schmitt et al., 2008) (most similar to 2.A.1.1.32)BacteriaGlcP of Mycobacterium smegmatis (A0QZX3)

The tonoplast H+:Inositol symporter 1, Int1 (mediates efflux from the tonoplast to the cytoplasm (Schneider et al., 2008) (most similar to 2.A.1.1.63 and 2.A.1.1.62).


Int1 of Arabidopsis thaliana (Q8VZR6)

2.A.1.1.67Glucose/xylose facilitator-1, GXF1 (functions by sugar uniport; low affinity (Leandro et al., 2008)YeastGXF1 of Candida intermedia (Q2MDH1)

The Glucose Transporter/Sensor Rgt2


Rgt2 Pichia stipitis (A3M0N3)

2.A.1.1.69Sugar & polyol transporter 1 (SPT1): broad specificity; takes up glucose (Schilling and Oesterhelt, 2007). Loss of the first 3 TMSs of the 12 TMSs does not prevent sugar uptake or sugar recognition but lowers substrate affinity & transport rate, and abolished H+ symport (Schilling and Oesterhelt, 2007).Red algaeSPT1 of Galdieria sulphuraria (A1Z264)
2.A.1.1.7Quinate:H+ symporterFungiQay of Neurospora crassa

MFS Permease


MFS Permease of Phaeosphaeria nodurum


Hexose (glucose) transporter, GT4 (D2) (almost identical to 2.A.1.1.16). The L. infantum ortholog (A4I8N6) is 95% identical to this protein and is the dominant protein in the plasma membrane of this organims (Oliveira et al. 2020).


Hexose transporter, GT4 of Leishmania mexicana (B1PLM1)


The kidney basolateral urate efflux transporter (SLC2A9, URATv1 or GLUT9) (orthologue of 2.A.1.1.47) (Anzai et al., 2008). Human SLC2A9a and SLC2A9b isoforms mediate electrogenic transport of urate with different characteristics in the presence of hexoses (Witkowska et al., 2012).  It transports hexoses as well as urate, the latter by a uniport mechanism, thus catalyzing uptake as well as efflux. The ITM2B protein Q9Y287; 266 aas and 1 TMS) inhibits urate uptake and stimulates efflux (Mandal and Mount 2019). GLUT9's transcription is regulated by a hepatocyte nuclear factor, HNF4α (Prestin et al. 2014). Residues involved in urate transport have been identified (Long et al. 2017). Pathogenic variants of SLC22A12 (URAT1) and SLC2A9 (GLUT9) can give rise to renal hypouricemia (Perdomo-Ramirez et al. 2023).


SLC2A9 of Homo sapiens

2.A.1.1.73Glycerol uptake permease (Glycerol:H+ symporter) Stl1. (Involved in salt stress relief) (Kayingo et al. 2009) (similar to Stl1 of S. cerevisiae (2.A.1.1.38))


Stl1 of Candida albicans (Q5A8J5)


The putative L-rhamnose porter, RhaY

Firmicutes, Actinobacteria

RhaY of Listeria monocytogenes (Q926Q9)


The fructose/xylose:H+ symporter, PMT1 (polyol monosaccharide transporter-1). Also transports other substrates at lower rates. PMT2 is largely of the same sequence and function. Both are present in pollen and young xylem cells (Klepek et al., 2005). A similar ortholog has been identifed in pollen grains of Petunia hybrida (Garrido et al. 2006).


PMT1 of Arabidopsis thaliana (Q9XIH7)


Glucose transporter, GT1. GT1, 2, and 3 are homologues. GT2 and GT3 transport ribose as well as glucose at different rates. GT3 transports ribose with 6-fold lower efficiency due to two threonines in GT3 that are alanines in GT2. They are in two loops between TMSs 3, 4, and 7, 8 (Naula et al., 2010). GT1 is expressed in the flagellar membrane and may be both a glucose transporter and sensor, allowing the parasites to enter the stationary phase when they deplete glucose although in the absence of the sensor, they lose viability (Rodriguez-Contreras et al. 2015).


GT1 of Leishmania mexicana (Q9F315)


The D-glucose/D-ribose transporter, LmGT2 (Most similar to 1.A.1.1.18) (Naula et al., 2010).


LmGT2 of Leishmania mexicana (O61059)


The glucose transporter, LmGT3 (homologous to LmGT2 (1.A.1.1.75)). Two threonine residues located in the hydrophilic loops connecting TMSs 3 & 4 and 7 & 8 of GT3 prevent transport of D-ribose. Changing these two residues to alanine (as in GT2) allows transport of ribose. Thus, loops 3-4 and 7-8 partially determine substrate specificity (Naula et al., 2010).


LmGT3 of Leishmania mexicana (O61060)


Polyol (xylitol):H+ symporter, PLT4 (Kalliampakou et al., 2011)



PLT4 of Lotus japonicus (Q1XF07)


Myoinositol:H+ symporter




ITR1 of Saccharomyces cerevisiae


Insulin-responsive facilitative glucose transporter in skeletal and cardiac muscle, adipose, and other tissues, Glut4 (GTR4; SLC2A4; 509aas). Defects in Glut4 cause noninsulin-dependent diabetes mellitus (NIDDM). Hyperinsulinemia leads to uncoupled insulin regulation of the GLUT4 glucose transporter and the FoxO1 transcription factor (Gonzalez et al., 2011). The first luminal loop confers insulin responsiveness to GLUT4 (Kim and Kandror, 2012). Exercise increases Glut4 synthesis in a process involving several protein kinases, the Glut4 enhancer factor (GEF; SLC2A4 regulator; Q9NR83), and the myocyte enhancing factor 2 (MEF2; NP_001139257). (McGee and Hargreaves 2006; Wright 2007; Zorzano et al. 2005). monoclonal antibodies against the GLUT4 inward-open and outward-open states have been isoated (Tucker et al. 2018). It is phosphoryated by protein kinase C-β, PRKCB or PKCB (Lee et al. 2015). Insulin-induced GLUT4 transport is observed in the heart and brain in addition to the skeletal muscle and adipocytes, and hormones other than insulin can enhance GLUT4 transport (Wang et al. 2020). Prolonged preoperative fasting induces postoperative insulin resistance by ER-stress mediated Glut4 down-regulation in skeletal muscle (Lin et al. 2021). GLUT4 is the primary glucose transporter in adipose and skeletal muscle tissues, and its cellular trafficking is regulated by insulin signaling. Failed or reduced plasma membrane localization of GLUT4 is associated with diabetes. The cryo-EM structures of human GLUT4 bound to a small molecule inhibitor cytochalasin B (CCB) at resolutions of 3.3 Å which exhibits an inward-open conformation. The cryo-EM structure reveals an extracellular glycosylation site and an intracellular helix that is invisible in the crystal structure of GLUT1 (Yuan et al. 2022). Tectorigenin targets PKACα to promote GLUT4 expression in skeletal muscle and improve insulin resistance in vitro and in vivo (Yao et al. 2023). Key molecular players in insulin resistance (IR) are the insulin receptor and glucose transporter 4, and certain natural products, such as lipids, phenols, terpenes, antibiotics and alkaloids have beneficial effects on IR which are named "membrane-active immunomodulators" (MAIMs) (Izbicka and Streeper 2023). An example is the medium chain fatty acid ester diethyl azelate (DEA), which increases the fluidity of plasma membranes with subsequent downstream effects on cellular signaling and improves the symptoms of IR. The intracellular helical bundle of human glucose transporter GLUT4 is important for complex formation with ASP (Huang et al. 2023). Diabetes-induced electrophysiological alterations on neurosomes in ganglia of the peripheral nervous system have been reported (Leal-Cardoso et al. 2023). Regulated dynamic subcellular GLUT4 localization has been revealed by proximal proteome mapping in human muscle cells (Ray et al. 2023). In goats, this system is closely associate with lipid metabolism (Zhang et al. 2024).


SLC2A4 of Homo sapiens


The glucose uptake porter, GluP (Araki et al., 2011).


GluP of Rhodococcus jostii (Q0SE66)


The cellobiose/cellotriose/cellotetraose/latose/cellodextrin transporter, Cdt-1 of 579 aas and 12 TMSs. It is a proton symporter with a Km of about 4 μM (Galazka et al., 2010).


Cdt-1 of Neurospora crassa (Q7SCU1)


The cellobiose/cellotriose/cellodextrin/lactose transporter, Cdt-2, of 525 aas and 12 TMSs. It functions by facilitated diffusion but with low efficiency and high affinity (Km = 3 μM). Mutations can increase its activity substantially (Lian et al. 2014). It appears to be capable of catalyzing efflux of 2'-fucosyllactose (2'FL), the most abundant oligosaccharide in human breast milk, following genetic engineering (Hollands et al. 2019).  It may also take up lactose (Tamayo et al. 2024).


Cdt2 of Neurospora crassa (Q7SD12)


The heteromeric TMT1/TMT2 glucose/sucrose:H+ antiporter. Catalyzes glucose/sucrose antiport into vacuoles (Schulz et al., 2011).


The TMT1/2 sugar:H+ anti-porter of Arabidopsis thaliana. TMT1 (Q96290). TMT2 (Q8LPQ8).


Zebrafish Slc2A10 (Glut10) facilitative glucose transporter.


Zebrafish Glut10 of Danio rerio (A8KB28)


The sea bream facilitative glucose transporter 1 (GLUT1) (Balmaceda-Aguilera et al., 2012).


Glut1 of Sparus aurata (H9BPB6)


solute carrier family 2, member 12, Glut12 of 617 aas and 12 TMSs.  In contrast to most mammalian members of this family, this protein has been reported to be a glucose:proton symporter (Wilson-O'Brien et al. 2010).


SLC2A12 of Homo sapiens

2.A.1.1.88 solute carrier family 2 (facilitated glucose transporter), member 6AnimalsSLC2A6 of Homo sapiens
2.A.1.1.89Solute carrier family 2, facilitated glucose transporter member 8 (Glucose transporter type 8) (GLUT-8) (Glucose transporter type X1)AnimalsSLC2A8 of Homo sapiens
2.A.1.1.9Lactose, galactose:H+ symporterYeastLacP of Kluyveromyces lactis
2.A.1.1.90Solute carrier family 2, facilitated glucose transporter member 14 (Glucose transporter type 14) (GLUT-14)AnimalsSLC2A14 of Homo sapiens

Solute carrier family 2, facilitated glucose transporter member 3 (Glucose transporter type 3, brain) (GLUT-3 or GLUT3). It mediates the facilitative uptake of glucose, 2-deoxyglucose, galactose, mannose, xylose and fucose, and probably dehydroascorbate, but not fructose (Seatter et al. 1998, Deng et al. 2015).  GLUT3, a key neuronal transporter, exhibits multiple intermediate states (Sun and Zheng 2019). SLC2A3 may play a role in the progression of colorectal cancer (CRC) by regulating the epithelial-mesenchymal transition (EMT) classical pathway as well as PD-L1 mediated immune responses (Gao et al. 2021). GLUT3 is consistently upregulated in actively proliferating human oral squamous cell carcinoma cells (Paolini et al. 2022). GLUT-1 and GLUT-3 play roles in the development of some types of malignant tumors including glioblastoma, and expression of both is regulated by miRNAs (Beylerli et al. 2022). The overexpression of GLUT3 or GLUT1 may be monitored alone or in combination (GLUT1/GLUT3 ratio) as a biomarker for preeclampsia onset, phenotype, and progression (Agbani et al. 2023).


SLC2A3 of Homo sapiens


Inner membrane metabolite transport protein YdjE


YdjE of E. coli

2.A.1.1.93Vacuolar protein sorting-associated protein 73FungiVPS73 of Saccharomyces cerevisiae
2.A.1.1.94Putative metabolite transport protein YDL199CFungiYDL199C of Saccharomyces cerevisiae

Inner membrane metabolite transport protein YgcS



YgcS of E. coli

2.A.1.1.96Probable metabolite transport protein YBR241CFungiYBR241C of Saccharomyces cerevisiae
2.A.1.1.97Sugar transporter ERD6 (Early-responsive to dehydration protein 6) (Sugar transporter-like protein 1)PlantsERD6 of Arabidopsis thaliana

Sugar transporter ERD6-like 6, ERD6L6, of 487 aas and 12 TMSs.  It is 92% identical to ERD6L4 (488 aas and 12 TMSs) of A. thaliana, and ERD6-like 4 is candidate gene for foliar water-soluble carbohydrate accumulation in Trifolium repens (Pearson et al. 2022). Vacuolar sugar transporter EARLY RESPONSE TO DEHYDRATION 6-LIKE4 affects fructose signaling and plant growth (Khan et al. 2023). Regulation of intracellular sugar homeostasis is maintained by regulation of activities of sugar import and export proteins residing at the tonoplast. ERDL4 protein resides in the vacuolar membrane in Arabidopsis thaliana. Gene expression and subcellular fractionation studies indicated that ERDL4 participates in fructose allocation across the tonoplast, and modification of cytosolic fructose levels influences plant organ development and stress tolerance (Khan et al. 2023).



At1g75220 of Arabidopsis thaliana


Facilitated trehalose transporter Tret1-1 (DmTret1-1); transports trehalose with a Km of 11 mM (Kanamori et al. 2010).  Tret1 orthologs of other insects examined have differing Km values (Apis mellifera, 9 mM; Anopheles gambiae, 46 mM, and Bombyx mori, 72 mM).


Tret1-1 of Drosophila melanogaster


2.A.1.10 The Nucleoside: H+ Symporter (NHS) Family


TC#NameOrganismal TypeExample

Nucleoside porter, NupG.  Guanosine, inosine, cytidine and thymidine but not uridine, adenosine and xanthosine are transported (Patching et al. 2005). ADP-glucose is also a substrate of this system (Almagro et al. 2018).


NupG of E. coli (P0AFF4)


Xanthosine porter, XapB.  Xanthosine, inosine, adenosine, cytidine and thymidine but not guanosine and uridine are transported (Seeger et al. 1995). The Km for Xanthosine is 136 μM (Nørholm and Dandanell 2001). The transporter is encoded within an operon with xanthosine phosphorylase which is inactive in S. enterica but can be mutated to the active form (Hansen et al. 2006).

XapB of E. coli


Putative low affinity ribonucleoside transporter, YegT, of 425 aas and 12 TMSs.


YegT of Escherichia coli


2.A.1.11 The Oxalate:Formate Antiporter (OFA) Family


TC#NameOrganismal TypeExample

The oxalate:formate antiporter.  Residues and TMSs involved in the translocation pathway and substrate binding have been identified (Fu and Maloney 1998; Fu et al. 2001; Ye and Maloney 2002; Wang et al. 2006). Beuming and Weinstein 2005 developed a method to predict the structures of membrane proteins consisting of (1) identifying TMSs from sequence; (2) assigning buried and lipid-exposed faces of the TMSs; and (3) assembling the TMSs into a bundle, based on geometric restraints obtained from EM data. The OxlT structure was modeled (Beuming and Weinstein 2005).


OxlT of Oxalobacter formigenes


MFS carrier of 577 aas and 12 TMSs

MFS protein of Entamoeba histolytica


Putative MFS transporter of 399 aas; 12 TMSs.


MFS porter of Pseudomonas aeruginosa (Q9I458)


Inner membrane protein BtsT or YhjX (probably a pyruvate:proton symporter that can also function as an exporter) (Vilhena et al. 2017).  Regulated by Crp as well as the LytS-like histidine sensor kinase, BtsS or YehU, and the corresponding LytTR-like response regulator, BtsR or YehT (Kristoficova et al. 2017).  Possibly induced by peptides as cells enter the stationary growth phase because they release extracellular pyruvate, the true inducer (Kristoficova et al. 2017).  Forms a complex with the BtsT (CsiA; YjiY) transporter (TC# 2.A.114.1.9) and two sensor kinase/response regulator pairs, BtsS/BtsR (YehU/YehT) and YdpA/YdpB, both of which respond to extracellular pyruvate, but with differing affinities (Behr et al. 2014).  The carbon storage regulator A (CsrA) is involved in posttranscriptional regulation of both BtsT (YjiY) and YjiX, a 67 aa soluble protein of unknown function (Behr et al. 2014). The two proteins, YhjX (TC# 2.A.1.11.3) and YjiY (TC# 2.A.114.1.9) may function together as an oligomer, and confusingly, have both been given the designation: BtsT (see UniProt entries). 


BtsT or YhjX of Escherichia coli

2.A.1.11.4Uncharacterized membrane protein YJL163CFungiYJL163C of Saccharomyces cerevisiae

MFS-type transporter YcxA (ORF5) of 408 aas and 12 TMSs.  Capable of exporting the peptide antibiotic, surfactin, synthsized by a non-ribosome mechanism in B. subtilis (Li et al. 2015).


YcxA of Bacillus subtilis


Uncharacterized MFS-type transporter YbfB


YbfB of Bacillus subtilis


Uncharacterized protein of 512 aas and 12 TMSs.


UP of Chondrus crispus


Uncharacterized protein of 404 aas


UP of Pseudomonas aeruginosa


Uncharacterized MFS porter of 508 aas and 12 TMSs.

UP of Entamoeba histolytica


2.A.1.12 The Sialate:H+ Symporter (SHS) Family


TC#NameOrganismal TypeExample

The sialic acid porter, NanT, of 496 aas and 14 TMSs.  N-acetylneuraminic acid (Neu5Ac) serves as a sole source of carbon and nitrogen for E. coli.  It is a mucus-derived carbon source in the mammalian gut. NanT can also take up and allow efficient growth on the related sialic acids, N-glycolylneuraminic acid (Neu5Gc) and 3-keto-3-deoxy-d-glycero-d-galactonononic acid (KDN) (Hopkins et al. 2013). In animals, N-glycolylneuraminic acid is transported by exo- and endo-cytosis (He et al. 2023).


NanT of E. coli


The lactate/pyruvate:H+ symporter of 616 aas and 12 TMSs. Residues in the substrate translocation pathway have been reported (Soares-Silva et al., 2011). This systems and its orthologs in fungi have been reviewed (Guo et al. 2018).


Jen1 (YKL217w) of Saccharomyces cerevisiae


Jen2 of 513 aas and 12 TMSs.  It is a dicarboxylic acid (succinate, malate, fumarate) uptake porter, and is subject to catabolite repression by glucose. It is induced during infection, being upregulated following the phagocytosis of C. albicans cells by neutrophils and macrophages.  It may be important during early stages of virulence (Vieira et al. 2010). In  the acid-tolerant yeast, Pichia kudriavzevii, it transports the above mentioned dicarboxylates as well as α-ketoglutarate (sometimes) and citrate, and possibly lactate (Xi et al. 2021).

Jen2 of Candida albicans


Jen1 of 541 aas and 12 TMSs. Zt is a monocarboxylate (lactate) uptake porter that is upregulated following the phagocytosis of Candida albicans cells by neutrophils and macrophages. It may be important for virulence (Soares-Silva et al. 2013; Vieira et al. 2010). It may be the only lactate uptake porter and is subject to glucose catabolite repression. However, growth on lactate affects biofilm formation, morphology and susceptibility to fluconazole, and both Jen1 and Jen2 may play a role in these processes. Thus, the adaptation of Candida cells to the carbon source present in the host niches affects their pathogenicity (Alves et al. 2017; Alves et al. 2020).

Jen1 of C. albicans


TC#NameOrganismal TypeExample

2.A.1.13 The Monocarboxylate Transporter (MCT) Family (Halestrap, 2011)

MCTs play roles in the absorption, tissue distribution, and clearance of both endogenous and exogenous compounds. MCTs are required for the transport of essential cell nutrients and for cellular metabolic and pH regulation (Jones and Morris 2016).


TC#NameOrganismal TypeExample

The low affinity proton-linked monocarboxylate (lactate, pyruvate, mevalonate, branched chain oxo acids, β-hydroxybutyrate, γ-hydroxybutyrate, butyrate, acetoacetate, acetate and formate, succinate) uptake/efflux porter (Moschen et al. 2012; Reddy et al. 2020). pH-gated succinate secretion regulates muscle remodeling in response to exercise (Reddy et al. 2020). The structural basis of MCT1 inhibition by anti-cancer drugs has been considered (Wang et al. 2020). MCT1 also transports anti-tumor alkylating agents, 3-bromopyruvate and dichloroacetate (Cooper et al. 1989; Su et al. 2016; Bailey et al. 2019) as well as artemisinin (Girardi et al. 2020). Activity is stimulated by direct interaction with carbonic anhydrase isoform II (Becker et al., 2005). This transporter interacts physically with the chaperone protein Basigin (CD147; TC #8.A.23.1.1) which is required both for targetting to the plasma membrane and for activity. Mct-2 uses a different chaperone protein, GP70. Mct-1 also transports the methionine hydroxy analogue 2-hydroxy (4-methylthio) butanate (Martin-Venegas et al., 2007; Becker and Deitmer, 2008). MCT1, 3 and 4 require the ancillary protein, basigin (P35613; 8.A.23.1.1) for plasma membrane localization (Ovens et al., 2010).  It partially localizes to the peroxysomal membrane (Visser et al. 2007). MCT1 is regulated by CD147 proteins, and this association is important for lactate export and cell proliferation in certain cancer cells (Walters et al. 2013).  It is upregulated in some cancers and maintains the metabolic phenotype of these cancer cells by mediating lactate efflux together with a proton, promoting pH homeostasis (Baltazar et al. 2014). MCT-1 functions as a positive regulator of osteoblast differentiation via suppression of p53 (Sasa et al. 2018). It plays a role in aggressive breast cancer subtypes (Li et al. 2018) as well as other cancers (Park et al. 2018).  The SLC16A1 gene is a potential marker to predict race performance in Arabian horses (Ropka-Molik et al. 2019). MCT1 is a negative regulator and MCT2 and a positive regulator of osteoclast differentiation, while MCT2 is required for bone resorption by osteoclasts (Imai et al. 2019). MCTs 1 and 4 are present in increased amounts in solid tumors, and inhibitors as potential therapeutics have been reviewed (Puri and Juvale 2020). Interleukin-1beta induces monocarboxylate transporter-1 in an oxygen tension-dependent manner (Tanaka et al. 2022). Substrate protonation is a pivotal step in the mechanisms of several MCT-unrelated weak acid translocating proteins, but utilization of the proton binding and transfer capabilities of the transporter-bound substrate is probably a universal theme for weak acid anion/H+ cotransport (Geistlinger et al. 2023). This transporter is over expressed in breast cancer (Arponen et al. 2023). Fasting upregulates MCT1 at the rat blood-brain barrier through PPAR δ activation (Chasseigneaux et al. 2024).  The anticancer effect of androgen deprivation therapy can be enhanced by an MCT1 inhibitor in prostate cancer cells (Kim et al. 2024).


MCT1 (SLC16A1) of Homo sapiens


MCT8 (SLC16a2) homodimeric monocarboxylate thyroid hormone transporter 8 of 613 or 539 aas and 12 TMSs (Visser et al. 2009; Arjona et al., 2011).  It is the X-linked mental retardation Allan-Herndon-Dudley syndrome (AHDS) (a severe psychomotor retardation syndrome) protein (Schweizer and Köhrle 2012; Boccone et al. 2010; Johannes et al. 2016). Lack of MCT8 function produces serious neurological disturbances, most likely due to impaired transport of thyroid hormones across brain barriers during development, resulting in severe brain hypothyroidism (Grijota-Martínez et al. 2020). Arg residues important for function have been identified (Groeneweg et al. 2013).  Thyroid hormone (TH) transporters in the brain and across the blood brain barrier have been reviewed (Wirth et al. 2014; Bernal et al. 2015). The product facilitates both TH uptake and efflux across the cell membrane. The disease goes together with low serum T4 and high T3 levels. The mechanisms underlying MCT8-deficient brain development in various animal models including humans has been reviewed (Vancamp and Darras 2017). Together with OATP1C1 (TC# 2.A.60.1.15), MCT8 controls skeletal muscle regeneration (Mayerl et al. 2018).  Deafness and loss of cochlear hair cells occurs in the absence of thyroid hormone transporters, Slc16a2 (Mct8) and Slc16a10 (Mct10) (Sharlin et al. 2018). Stable levels of MCT8 protein in endothelial cells of the blood-brain barrier, choroid plexus epithelial cells and tanycytes during postnatal development has been demonstrated (Wilpert et al. 2020). Oligomerization involves noncovalent interactions between the N-terminal halves of MCT8 proteins (Groeneweg et al. 2020). Genetic variants in MCT8, cause intellectual and motor disability and abnormal serum thyroid function tests, known as MCT8 deficiency (van Geest et al. 2020). Shaji 2021 identified natural inhibitors against MCT8. Emodin exhibited the best binding energy of -8.6 kcal/mol followed by helenaquinol, cercosporamide and resveratrol. Emodin and helenaquinol exhibit high binding energy. Cercosporamide and resveratrol exhibited higher binding energy than triac and desipramine and showed the binding energy similar to silychristin. Thus, these compounds could be promising candidates for further evaluation for AHDS prevention. MCT8 deficiency induces severe X-linked psychomotor retardation (Iwayama et al. 2021). It is common and severe in homozygous males (one X chromosome) but mild in heterozygous females (XX) (Dumitrescu et al. 2004). Thyroid normone transporters MCT8 and OATP1C1 are expressed in pyramidal neurons and interneurons in the adult motor cortex of human and macaque brains (Wang et al. 2023). Thyroid hormone transporters MCT8 and OATP1C1 are expressed in projection neurons and interneurons of basal ganglia and motor thalamus in adult human brains (Wang et al. 2023). MCT8 plays a vital role in maintaining brain thyroid hormone homeostasis. This transporter is expressed at the brain barriers, as the blood-brain barrier (BBB), and in neural cells, being the sole known thyroid hormone-specific transporter to date. Inactivating mutations in the MCT8 gene cause the Allan-Herndon-Dudley Syndrome (AHDS) or MCT8 deficiency, a rare X-linked disease characterized by delayed neurodevelopment and severe psychomotor disorders as well as BBB leakage (Guillén-Yunta et al. 2023). A novel SLC16A2 gene mutation produced a rare case of delayed myelination with dysthyroidism, v Allan-Herndon-Dudley syndrome (Mahesan et al. 2023). MCT8 inhibitors include methylmercury, bisphenol-AF and bisphenol-Z as well as previously known MCT8 inhibitors (Wagenaars et al. 2024).


SLC16A2 of Homo sapiens


Solute carrier family 16, member 5 (monocarboxylic acid transporter 6) of 505 aas and 12 TMSs. Found on the luminal side of small intestinal epithelial cells (Kohyama et al. 2013). MCT6 mediates uptake of nateglinide, an oral hypoglycemic agent. The K(t) for nateglinide is 46 μM. Thus, MCT6 may play a role in the intestinal absorption of nateglinide, although other transporters are also likely to be involved (Kohyama et al. 2013).


SLC16A5 of Homo sapiens


Solute carrier family 16, member 14 (monocarboxylic acid transporter 14), ATBo or MCT14.  Transports carnitine with low affinity (~ 1 mM) (Ingoglia et al. 2015). Its tissue localization in the mouse has been determined (Roshanbin et al. 2016).



SLC16A14 of Homo sapiens

2.A.1.13.13 solute carrier family 16, member 11 (monocarboxylic acid transporter 11)AnimalsSLC16A11 of Homo sapiens

Solute carrier family 16, member 12, SLC16A12, or monocarboxylic acid transporter 12; MCT12. Facilitative monocarboxylate transporter that mediates creatine transport across the plasma membrane (Abplanalp et al. 2013; Takahashi et al. 2020). It is the cataract and glucosuria associated monocarboxylate transporter.


SLC16A12 of Homo sapiens


Monocarboxylate transporter 7 (MCT 7; mTORC1) (Monocarboxylate transporter 6) (MCT 6) (Solute carrier family 16 member 6) of 523 aas and 12 TMSs in a 6 + 6 TMS arrangement. SLC16a6, mTORC1, and autophagy regulate ketone body excretion in intestinal cells (Uebanso et al. 2023).


SLC16A6 of Homo sapiens

2.A.1.13.16Monocarboxylate transporter 9 (MCT 9) (Solute carrier family 16 member 9)AnimalsSLC16A9 of Homo sapiens
2.A.1.13.17Monocarboxylate transporter 13 (MCT 13) (Solute carrier family 16 member 13)AnimalsSLC16A13 of Homo sapiens
2.A.1.13.18Probable transporter MCH2FungiMCH2 of Saccharomyces cerevisiae S288c
2.A.1.13.19Probable transporter MCH4FungiMCH4 of Saccharomyces cerevisiae

The low affinity aromatic amino acid (Tyr, Trp, Phe) transporter, TAT1 (T-type amino acid transporter), MCT10, Slc16a10.  Also transports N-methyl amino acids and thyroid hormones.  Essential for aromatic amino acid homeostasis in various tissues of mice (Mariotta et al. 2012). MCT10 is 58% identical to MCT8. Both transporters mediate T3 transport, but while MCT8 also transports rT3 and T4, these compounds are not efficiently transported by MCT10.  A few amino acyl residue substitutions in the human orthologue broadens the substrate specificity of this porter (Johannes et al. 2016). The Six1 trahscription factor promotes a skeletal muscle thyroid hormone response through regulation of the MCT10 transporter (Girgis et al. 2021).


Tat1 of Rattus norvegicus


Putative permease of 468 aas


Putative permease of Galdieria sulphuraria


MFS porter of 392 aas


MSF porter of Pseudomonas stutzeri


SLC16 Family protein of 771 aas and 12 TMSs, GEM-1.  GEM-1 acts in parallel to the GON-2 channel (TC# 1.A.4.5.10) to promote cation uptake within the developing gonad (Kemp et al. 2009).


Gem1 of Caenorhabditis elegans


Chicken MCT8 of 509 aas and 12 TMSs.  Transports pro-thyroid hormone, T4, with high affiinity, and T3 as well (Nele Bourgeois et al. 2016).

MCT8 of Gallus gallus (Chicken)


MCT10 (SLC16A10) of 400 aas and 11 TMSs.  Transports thyroid hormones, especially T3 (Nele Bourgeois et al. 2016).

MTC10 of Gallus gallus (chicken)


Thyroid hormones (TH) transporter, MCT8 of 526 aas and 12 TMSs (Zada et al. 2017). The mechanisms underlying MCT8-deficient brain development in various animal models including zebra fish and humans has been reviewed (Vancamp and Darras 2017).

TH transporter of Danio rerio (Zebrafish) (Brachydanio rerio)


Thyroid hormones (TH) transporter, MCT10 of 505 aas and 12 TMSs.

MCT10 of Danio rerio (Zebrafish) (Brachydanio rerio)


MfsG of 447 aas and 12 TMSs.  Exports fungicides such as glucosinolates and isothiocyanates. Exposure to glucosinolate-breakdown products induces expression of mfsG. MfsG functions in fungitoxic compound efflux (Vela-Corcía et al. 2019).

MfsG of Botryotinia fuckeliana (Noble rot fungus) (Botrytis cinerea)


Uncharacterized protein of 652 aas and 12 TMSs

UP of Trachymyrmex zeteki


The thyroid hormone transporter, MCT8 (transports L- and D-isomers of thyroxine (T4), 3,3',5-triiodothyronine (T3), 3,3'5'-triiodothyronine (rT3) and 3,3'-diiodothyronine [Km values = 2-5 μM; Leu, Phe, Trp and Tyr were not transported]) (Friesema et al., 2003). Loss of function mutations in MCT8 leads to Allan-Herndon-Dudley syndrome, severe X-linked psychomotor retardation and elevated serum T3 levels (Jansen et al., 2008). Essential molecular determinants for thyroid hormone transport and their structural implications are presented by Kinne et al. (2010). Induced by retinoic acid (Kogai et al., 2010). Mediates energy-independent bidirectional transport. MCT8 is specific for L-iodothyronines and requires at least one iodine atom per aromatic ring. Thyronamines, decarboxylated metabolites of iodothyronines, triiodothyroacetic acid and tetraiodothyroacetic acid, TH derivatives lacking both chiral center and amino group, are not substrates (Kinne et al., 2010). A deficiency causes altered thyroid morphology and a persistent high triiodothyronine/thyroxine ratio after thyroidectomy (Wirth et al., 2011). Primary and secondary thyroid hormone transporters have been reviewed (Kinne et al., 2011). A differential effect of a shortage of thyroid hormone was observed compared with a knockout of thyroid hormone transporters Mct8 and Mct10 on murine macrophage polarization (Hoen et al. 2024).


MCT8 of Mus musculus (O70324)


The high affinity (17 μM) facilitated diffusion, riboflavin-regulated riboflavin uptake system, Mch5 (Reihl and Stolz, 2005)


Mch5 of Saccharomyces cerevisiae (NP_014951)


Low affinity monocarboxylate transporter-2 (MCT2). Transports γ-hydroxybutyrate (Wang and Morris, 2007). MCT2 requires the ancillary protein, embigin (Q6PCB8; 8.A.23.1.2) for plasma membrane localization (Ovens et al., 2010). It is present in neurons but not astrocytes where the low affinity MCT1 and MCT4 predominate (Hertz and Dienel 2013). Partially localizes to the peroxysomal membrane (Visser et al. 2007). MCT1 is a negative regulator and MCT2 a positive regulator of osteoclast differentiation, while MCT2 is required for bone resorption by osteoclasts (Imai et al. 2019). Atorvastatin exerts more selective inhibitory effects on hMCT2 than on hMCT1 and hMCT4 (Yamaguchi et al. 2023).


MCT2 (SLC16A7) of Homo sapiens


Plasma membrane proton-linked monocarboxylate transporter, MCT4 or MCT-4 (SLC16A3). It catalyzes the rapid low affinity plasma membrane transport of many monocarboxylates such as lactate, pyruvate, branched-chain oxo acids derived from leucine, valine and isoleucine, and the ketone bodies acetoacetate, beta-hydroxybutyrate and acetate.  It is the main transporter that catalyzes lactate efflux from glycolyzing cells (Halestrap 2013; Papakonstantinou et al. 2021).  Residues binding high affinity inhibitors have been identified (Nancolas et al. 2015).  It forms a complex with binding partner, CD147/BSG, which regulates the transport activity (Fisel et al. 2015). It plays a role in aggressive breast cancer subtypes (Li et al. 2018) as well as other cancers (Park et al. 2018).  MCT4 may be a therapeutic target for colorectal cancer (Kim et al. 2018). MCTs 1 and 4 are present in increased amounts in solid tumors, and inhibitors are potential therapeutics (Puri and Juvale 2020). Anagliptin promotes apoptosis in mouse colon carcinoma cells via MCT-4/lactate-mediated intracellular acidosis (Li et al. 2022). Dietary folate deficiency promotes lactate metabolic disorders that sensitize lung cancer metastasis through mTOR-signaling-mediated targets (Chen et al. 2023). Shikonin reduced MCT4 expression and activation, resulting in inhibition of aerobic glycolysis in cancer-associated fibroblasts (CAFs) and overcoming CAF-induced gemcitabine resistance in pancreatic cancer (PC). Shikonin is a promising chemosensitizing phytochemical agent when used in combination with gemcitabine for PC treatment. The results suggest that disrupting the metabolic coupling between cancer cells and stromal cells might provide an attractive strategy for improving gemcitabine efficacy (Hu et al. 2024).


MCT4 (SLC16A3) of Homo sapiens


Monocarboxylate transporter-5 (MCT5 or SLC16A4; sometimes referred to as MCT4). Lactate transport via the MCT5 is non enzymatically stimulated by carbonic anhydrase II (Becker et al., 2010). MCTs require an ancillary 1TMS glycoprotein, either Embigin (Q6PCB8; TC# 8.A.23.1.2) or basigin (P35613; TC# 8.A.23.1.1) for plasma membrane localization (Ovens et al., 2010).  Upregulated in some cancers and maintains the metabolic phenotype of these cancer cells by mediating lactate efflux together with a proton, promoting pH homeostasis (Baltazar et al. 2014).  Also transports the chemotheraputic agent, 3-bromopyruvate (Baltazar et al. 2014).


SLC16A4 of Homo sapiens


Monocarboxylate transporter, MCT10. Transports thyroid horomones as well as aromatic amino acids (Visser et al., 2010). Primary and secondary thyroid hormone transporters have been reviewed (Kinne et al., 2011).  Deafness and loss of cochlear hair cells occurs in the absence of thyroid hormone transporters, Slc16a2 (Mct8) and Slc16a10 (Mct10) (Sharlin et al. 2018). Tissue-specific functions of thyroid hormone transporters in mice, including MCT8, MCT10 and Oatp1c1 have been reviewed (Salveridou et al. 2020).


SLC16A10 of Homo sapiens


Short chain monocarboxylate (lactate) transporter 3, MCT3. MCT1, 3 and 4 require the ancillary protein, basigin (P35613; 8.A.23.1.1) for plasma membrane localization (Ovens et al., 2010).

AnimalsSLC16A8 of Homo sapiens

2.A.1.14 The Anion:Cation Symporter (ACS) Family


TC#NameOrganismal TypeExample
2.A.1.14.1Glucarate porterBacteriaGudT of Bacillus subtilis

Lysosomal sialate transporter (Salla disease and infantile sialate storage disease protein, Sialin, of 419 aas and 12 TMSs (Morin et al., 2004)). Also transports glucuronic acid and aspartate. Structure-function studies have identify crucial residues and substrate-induced conformational changes (Courville et al., 2010). Also called SLC17A5. The substrate binding pocket has been identified based on modeling studies (Pietrancosta et al., 2012).  NAAG (N-acetylaspartylglutamate) an abundant neuropeptide in the vertebrate nervous system that is released from synaptic terminals in a calcium-dependent manner and acts as an agonist at the type II metabotropic glutamate receptor mGluR3, is transported into synaptic vesicles before it is secreted. Lodder-Gadaczek et al. 2013 demonstrate that vesicular uptake of NAAG and the related peptide NAAG2 (N-acetylaspartylglutamylglutamate) is mediated by sialin (SLC17A5). Sialin is probably the only vesicular transporter for NAAG and NAAG2, because transport of both peptides was not detectable in vesicles isolated from sialin-deficient mice.  Sialin also transports nitrate in the plasma membrane of salivary glands (Qin et al. 2012). Sialin interacts with nitrate and participates in the regulation of NO production and cell biological functions for body homeostasis (Wang and Qin 2022). Sialin mediates the flux of sialic acid from lysosomes to the cytoplasm (Li et al. 2022). Altered sialin mRNA expression in the main tissues of male type 2 diabetes rats has been documented (Yousefzadeh et al. 2023).  Base editing corrects the common Salla disease SLC17A5 c.115C>T variant (Harb et al. 2023).


SLC17A5 of Homo sapiens

2.A.1.14.11Plasma membrane, high affinity nicotinate permease, Tna1YeastTna1 of Saccharomyces cerevisiae
2.A.1.14.12Plasma membrane, high affinity biotin:H+ symporter, Vht1YeastVht1 of Saccharomyces cerevisiae

Broad specificity brain synaptic vesicle anion:Na+ symporter (transports glutamate, phosphate, chloride, etc.)(BNPI, EAT-4, VGLUT1) Chloride and ketone bodies regulate VGLUT activities (Omote et al., 2011). 


BNPI of Rattus norvegicus


Probable D-galactarate (glucarate?):H+ symporter, GarP or YhaU.  May also function as a glucarate:glycerate antiporter (Moraes and Reithmeier 2012) and a glucose transporter.  This sequence is incomplete.


GarP (YhaU) of E. coli


Apical membrane renal proximal tubular voltage-driven but Na+-independent organic anion transporter, OATv1 (transports p-aminohippurate; probably transports organic anions but not cations and not inorganic phosphate. It may catalyze excretion of various drugs, xenobiotics, and their metabolites) (Jutabha et al., 2003)


OATv1 of Sus scrofa (Q7YQJ7)


The broad specificity brain synaptic vesicle anion transporter, VGLUT-2 (transports glutamate in a Δψ-dependent fashion requiring Cl-, but phosphate by a Na+-dependent mechanism via a different pathway/mechanism (Juge et al., 2006). VGLUT1-3 concentrate glutamate into synaptic vesicles before its exocytotic release. Two distinct roles for Cl- in both allosteric activation and permeation have been proposed (Chang et al. 2018). The 3-D structure has been solved at 3.8 Å resolution revealing mechanisms of substrate recognition and allosteric activation by low pH and Cl-. It shows how the activities of VGLUTs are coordinated by changes in proton and chloride concentration during the synaptic vesicle cycle (Li et al. 2020).


VGLUT2 of Rattus norvegicus (Q9JI12)

2.A.1.14.17Pantothenate:H+ symporter, Liz1 (mutants cause abnormal mitosis due to a defect in ribonucleotide reductase) (Stolz et al., 2004)YeastLiz1 of Schizosaccharomyces pombe (O43000)
2.A.1.14.18Pantothenate:H+ symporter, Fen2YeastFen2 of Saccharomyces cerevisiae (P25621)
2.A.1.14.19Plasma membrane, high affinity vitamin H transporter 1 (H+:biotin symporter), Vht1 (Stolz, 2003)YeastVht1 of Schizosaccharomyces pombe (O13880)

Hexuronate (glucuronate; galacturonate) porter, ExuT (Nemoz et al. 1976). It also transports D-glucose (Kim et al. 2020).


ExuT of E. coli (P0AA78)


Endoplasmic reticular cysteine transporter, Yct1 (Kaur and Bachhawat, 2007)


Yct1 of Saccharomyces cerevisiae (Q12235)


The vesicular purine nucleotide (ADP, ATP, GTP) transporter, VNUT or SLC17A9. It is found in synaptic vesicles and chromafin granules (Sawada et al., 2008)) and is associated with disseminated superficial actinic porokeratosis (DSAP), a rare autosomal dominant genodermatosis (Cui et al. 2014). It plays a key role in purinergic signaling through its ability to transport nucleotides using the pmf. It catalyzes Cl--dependent transport activity involving essential arginines in the transmembrane region. Ketoacids inhibit these transporters through modulation of Cl- activation, but Cl- and the arginine residues are not important for ATP binding (Iwai et al. 2019). High expression of SLC17A9 correlates with a poor prognosis for colorectal cancer (Yang et al. 2019).


SLC17A9 of Homo sapiens


The chloroplast thylakoid Na+:phosphate symporter, ANTR1 (512aas) (Pavón et al., 2008). Residues essential for function have been identified (Ruiz-Pavón et al., 2010).


ANTR1 of Arabidopsis thaliana (O82390)


Vesicular glutamate transporter #3 (VGLUT3) [Its absence in mice causes sensorineural deafness and seizures]. 70% identical to VGLUT2 (TC# 2.A.1.14.16) (Gras et al., 2002). VGLUT1-3 concentrate glutamate into synaptic vesicles before its exocytotic release and contribute to the regulation of serotonergic transmission and anxiety (Amilhon et al., 2010). It may catalyze uptake of the neurotransmitter coupled with H+ export and K+ uptake (Farsi et al. 2016).


VGLUT3 of Mus musculus (Q8BFU8)


Intestinal mucosal sodium/phosphate symporter, SLC17A4. Maintains phosphate homeostasis; mediates intestinal absorption, bone deposition and resorption and renal excretion.

AnimalsSLC17A4 of Homo sapiens

The putative D-mannuronate porter, AlgT (Rodionov et al., 2010).


AlgT of Shewanella frigidimarina (Q07YH1)


The plasma membrane Lethal (2)01810 glutamate uptake porter (Km=0.07μM) (Inhibited by aspartate) (Shim et al., 2011)


L(2)01810 of Drosophila melanogaster (F2YPN7)


Voltage-driven Na+:phosphate cotransporter; solute carrier family 17, member 1.  Orthologous to 2.A.1.14.6.  Transports other anions including urate; functions in urate cell elimination at the renal apical membrane (Prestin et al. 2014).


SLC17A1 of Homo sapiens


Solute carrier family 17 (sodium phosphate), member 3.  Catalyzes voltage-driven Na+:phosphate cotransport, but also functions in cell elimination of urate at renal tubular cell apical membranes (Prestin et al. 2014).


SLC17A3 of Homo sapiens

2.A.1.14.29Sodium-dependent phosphate transport protein 3 (Na(+)/PI cotransporter 3) (Sodium/phosphate cotransporter 3) (Solute carrier family 17 member 2)AnimalsSLC17A2 of Homo sapiens

Putative tartrate porter, TtuB or TUB3, of 449 aas and 12 TMSs.


TtuB of Agrobacterium vitis


Vesicular glutamate transporter 1, VGluT1 or PNP1 of 560 aas and 12 TMSs. Brain-specific Na+-dependent inorganic phosphate cotransporter; Solute carrier family 17 member 7). Several proteins must be retrieved to the synaptic vesicle before it can export neurotransmitters, and cargo retrieval is a collective cargo-driven process, dependent on VGluT1 (Pan et al. 2015).  The amino-terminal and carboxyl-terminal regions of VGLUT2 in membranes face the cytoplasm (Jung et al. 2006). It is involved in nervous system diseases (Du et al. 2020). VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems (Zhang et al. 2018). An overview of the physiologic sites for VGLUT regulation that can modulate glutamate release in an over-active synapse or in a disease state has been presented (Pietrancosta et al. 2020).


SLC17A7 of Homo sapiens


Vesicular glutamate transporter 2 (VGluT2) (Differentiation-associated BNPI) (Differentiation-associated Na+-dependent inorganic phosphate cotransporter) (Solute carrier family 17 member 6, SLC17A6). It has 582 aas with 12 probable TMSs. It is expressed in different nerve fibre populations that selectively contact pulmonary neuroepithelial bodies (Brouns et al. 2004).


SLC17A6 of Homo sapiens

Vesicular glutamate transporter 3 (VGluT3) (Solute carrier family 17 member 8). Loss in mice produces circadian-dependent hyperdopaminergia and amiliorates motor disfunction and dopa-mediated dyskinesias in a model of Parkinson's Disease (Divito et al. 2015). VGLUT3 is expressed selectively in the inner hair cells (IHCs) and transports the neurotransmitter glutamate into synaptic vesicles. Mutation of the SLC17A8 gene is associated with DFNA25 (deafness, autosomal dominant 25), a non-syndromic hearing loss (ADNSHL) in humans (Ryu et al. 2016). Glut3 contributes to stress response and related psychopathologies (Horváth et al. 2018). An adeno-associated virus carrying the Slc17a8 gene restored vesicular Glut3 in the inner hair cells of the cochlea, thereby rescuing loss in mice that lacked Glut3 (Mathiesen et al. 2023).


SLC17A8 (VGluT3) of Homo sapiens


Putative L-galactonate transporter, YjjL


YjjL of Escherichia coli

2.A.1.14.34Putative inorganic phosphate cotransporterAnimalsPicot of Drosophila melanogaster
2.A.1.14.35Inner membrane transport protein RhmTBacteria

RhmT of Escherichia coli

2.A.1.14.36Thiamine pathway transporter THI73FungiTHI73 of Saccharomyces cerevisiae
2.A.1.14.37Probable transporter SEO1FungiSEO1 of Saccharomyces cerevisiae

Transporter YIL166c (Hellborg et al. 2008) of 542 aas and 12 TMSs. May transport inorganic sulfur-containing compounds such as sulfate, sulfite, thiosulfate and sulfonates.


YIL166c of Saccharomyces cerevisiae

2.A.1.14.39Uncharacterized transporter YybOBacilli

YybO of Bacillus subtilis

2.A.1.14.4Dipeptide (e.g., Gly-Leu), allantoate, ureidosuccinate, allantoin porter (Cai et al., 2007).YeastDal5 of Saccharomyces cerevisiae

Glucarate transporter, GudP.  Encoded in an operon with GudD, a glucarate dehydratase (Moraes and Reithmeier 2012).


GudP of E. coli


The Aldohexuronate (glucuronate, galacturonate) uptake porter (Valmeekam et al. 2001).


ExuT of Erwinia chrysanthemi  This sequence is incomplete.


Vesicular glutamate transporter, EAT-4/VGLUT of 576 aas (Serrano-Saiz et al. 2013).  EAT-4 is responsible for loading glutamate into synaptic vesicles, and thus in defining the glutamatergic phenotype of a neuron (Serrano-Saiz et al. 2013). 


EAT-4 of Caenorhabditis elegans


Uncharacterized but putative sulfonate (and other inorganic sulfur-containing compounds) uptake transporter of 537 aas and 12 TMSs.

UP of Ashbya gossypii (Yeast) (Eremothecium gossypii)


Vesicular Glutamate transporter, VGlut of 632 aas and 10 TMSs with the N- and C-termini in the cytoplasm (Fei et al. 2007).

VGlut of Drosophila melanogaster


AtPHT4;4, or ANTR2 of 541 aas and 12 TMSs, an ascorbate transporter in the chloroplast envelope membrane.  It may be required for tolerance to strong light stress (Miyaji et al. 2015).

ANTR2 of Arabidopsis thaliana


Vesicular glutamate transporter, VGLU-2, of 573 aas and 12 TMSs. In addition to being present in nerve cells, it may play a role in collagen trafficking in the skin. The C. elegans SLC17A6/7/8 family members probaly have diverse functions within and outside the nervous system (Serrano-Saiz et al. 2019).

VGLU-2 of Homo sapiens


MFS2 of 1379 aas and 12 TMSs in a 6 + 6 TMS arrangement at the C-terminal end of the protein (residues 800 - 1379).  The N-terminal 800 residues are strongly hydrophilic (Wunderlich 2022).

MFS2 of Plasmodium falciparum


MFS general substrate transporter of 451 aas and 12 TMSs, MFS-3-6. It facilitates the export of lactate from the cell under acidic conditions (Tian et al. 2022). 

MFS-3-6 of Weizmannia coagulans (strain 2-6) (Bacillus coagulans)


Uncharacterized MFS carrier of 453 aas and probably 12 TMSs in a 6 + 6 TMS arrangement. The encoding gene is responsive to the presence of Ivermectin (Dube et al. 2023).

UP of Caenorhabditis elegans


Phthalate porter, Pht1 of 451 aas and 11 or 12 TMSs.


Pht1 of Pseudomonas putida


MFS carrier, a putative drug exporter of 450 aas and 12 TMSs in a 6 + 6 TMS arrangement.  It exports polymyxin B, CCCP and verapamil (Gao et al. 2023).

Polymyxin exporter of Pandoraea pnomenusa


Na:Pi symporter, NPT1 or SLC17A1. (Renal chloride-dependent polyspecific anion exporter; transports organic acids such as p-aminohippurate, ureate, and acetylsalicylate (asprin)). Catalyzes ureate excretion. A mutant form shows increased risk of gout in humans.


Npt1 of Mus musculus

2.A.1.14.7Galactonate transporterBacteriaDgoT (YidT) of E. coli (P0AA76)
2.A.1.14.8Phthalate porterBacteriaOphD of Burkholderia cepacia
2.A.1.14.9Putative p-hydroxyphenylacetate porterBacteriaHpaX of Salmonella dublin

2.A.1.15 The Aromatic Acid:H+ Symporter (AAHS) Family


TC#NameOrganismal TypeExample

4-Hydroxybenzoate/protocatechuate porter (Nichols and Harwood 1997).


PcaK of Pseudomonas putida


The gentisate (2,5-dihydroxybenzoate) uptake porter, GenK (does not take up either benzoate or 3-hydoxybenzoate).


GenK of Corynebacterium glutamicum (Q8NLB7)


The Vanillate porter, VanK 


VanK of Corynebacterium glutamicum (Q6M372)


Inner membrane transport protein YdiM.  Catalyzes export of medium chain alcohols such as isoprenol (Wang et al. 2015).


YdiM of Escherichia coli


Inner membrane transport protein, YdiN (similar to 2.A.1.15.12).  Induced under carbon limitation but not phosphate limitation (Johansson and Lidén 2006).


YdiN of Escherichia coli


Probable uptake transporter for 2,4-dichlorophenoxyacetic acid (2,4-D), CadK (Kitagawa et al. 2002).


CadK of Bradyrhizobium sp. HW13


Unncharacterized permease of 436 aas and 12 TMSs.


UP of Treponema brennaborense


Aromatic/benzoate uptake transporter of 442 aas and 12 TMSs, BenK (Choudhary et al. 2017).

BenK of Pseudomonas putida


MhpT. A specific 3-(3-hydroxyphenyl)propionate (3HPP) transporter; vital for E. coli K-12 W3110 to grow on this substrate.  Transports 3HPP but not benzoate, 3-hydroxybenzoate or gentisate (Xu et al. 2013).  May also export arabinose but not xylose (Koita and Rao 2012).


MhpT of E. coli


2,4-Dichlorophenoxyacetate porter (Hawkins and Harwood 2002).


TfdK of Ralstonia eutropha


cis,cis-muconate porter, MucK (Williams and Shaw 1997).


MucK of Acinetobacter sp. ADP1

2.A.1.15.5Benzoate porter, BenKBacteriaBenK of Acinetobacter sp. ADPP1

Vanillate porter, VanK


VanK of Acinetobacter sp. ADP1


Aromatic compound (benzoate) uptake transporter of 450 aas (Clark et al. 2002).


BenK of Acinetobacter baylyi

2.A.1.15.8Probable 1-hydroxy-2-naphthoate transporter, orf1 (Iwabuchi and Harayama, 1997). BacteriaOrf1 of Nocardioides sp. (O24723)
2.A.1.15.9Probable 4-methylmuconolactone transporter, MmlH (Erb et al., 1998)BacteriaMmlH of Ralstonia eutropha (O51798)

2.A.1.16 The Siderophore-Iron Transporter (SIT) Family


TC#NameOrganismal TypeExample

Siderophore-iron (ferrioxamine):H+ symporter, Sit1 (Arn3) (in vesicles)


Sit1 (YEL065w) of Saccharomyces cerevisiae

2.A.1.16.2The ferric enterobactin:H+ symporter, Enb1YeastEnb1 (YOL158c) of Saccharomyces cerevisiae
2.A.1.16.3The ferric triacetylfusarinine C:H+ symporter, Taf1YeastTaf1 (YHL047c) of Saccharomyces cerevisiae
2.A.1.16.4The ferrichrome:H+ symporter, Arn1p (Moore et al., 2003)YeastArn1 of Saccharomyces cerevisiae (NP_011823)
2.A.1.16.5Siderophore iron transporter 2Yeaststr2 of Schizosaccharomyces pombe

Siderophore iron transporter 1, Str1


Str1 of Schizosaccharomyces pombe


Ferri-siderophore transporter, MirB. Transports hydroxamate siderophores such as triacetylfusarinine C (TAFC) (Raymond-Bouchard et al. 2012).


MirB of Emericella nidulans


Fusarum iron-related protein, Fir1 of 585 aas and 14 TMSs. Probably an iron-siderophre transporter (López-Errasquín et al. 2006).

Fir1 if Gibberella moniliformis (Maize ear and stalk rot fungus) (Fusarium verticillioides)


Siderophore iron transporter 3, Str3 of 630 aas and 14 TMSs in a 6 + 7 + 1 TMS arrangement. It transports siderophore iron and so plays a role in iron homeostasis (Pelletier et al. 2003). It also transports heme, and the peroxiredoxin, Tpx1 (Q74887; 192 aas and 0 - 2 possible TMSs), is a binding partner of Str3 (Normant et al. 2020). Under microaerobic conditions, cells deficient in heme biosynthesis and lacking the heme receptor Shu1 exhibit poor hemin-dependent growth in the absence of Tpx1, a cytoplasmic heme binding protein. Tpx1 exhibits an equilibrium constant value of 0.26 muM for hemin. The association of Tpx1 with hemin protects hemin from degradation by H2O2, and the peroxidase activity of hemin is lowered when it is bound to Tpx1 (Normant et al. 2020).

Str3 of Schizosaccharomyces pombe (Fission yeast)


2.A.1.17 The Cyanate Porter (CP) Family


TC#NameOrganismal TypeExample

Cyanate transport system, CynT.  Encoded with cyanate aminohydrolase, CynS, and carbonic anhydrase, CynX (Anderson et al. 1990; Moraes and Reithmeier 2012).


CynX of E. coli


Glucose transporter, OEOE_0819. Does not transport fructose (Kim et al., 2011)


OEOE_0819 of Oenococcus onei (Q04FN1)


Inner membrane transport protein, NimT or YeaN of 393 aas and 12 TMSs.  It exports 2-nitroimidazole from the cytoplasm, confering resistance to this anitbiotic, and transcription of this gene as well as NimO, within the same operon, is regulated by the repressor, NimR (YeaM) (Ogasawara et al. 2015).


NimT or YeaN of Escherichia coli


MFS porter of 390 aas and 12 TMSs

MFS porter of Campylobacter peloridis


2.A.1.18 The Polyol Porter (PP) Family


TC#NameOrganismal TypeExample

D-Arabinitol:H+ symporter of 425 aas and 12 TMSs, DalT (Heuel et al. 1997; Heuel et al. 1998).


DalT of Klebsiella pneumoniae


Ribitol:H+ symporter of 427 aas and 12 TMSs, RbtT (Heuel et al. 1997; Heuel et al. 1998).


RbtT of Klebsiella pneumoniae


Alpha-ketoglutarate permease of 435 aas and 12 TMSs (Gomez and Cutting 1997).


CsbX of Bacillus subtilis


2.A.1.19 The Organic Cation Transporter (OCT) Family (The SLC22A family including OCT1-3, OCTN1-3 and OAT1-5 of H. sapiens)

This family has been described by Koepsell 2013.  It contains 13 functionally characterized human plasma membrane proteins.The family includes organic cation transporters (OCTs), organic zwitterion/cation transporters (OCTNs), and organic anion transporters (OATs). The transporters operate as (1) uniporters which mediate facilitated diffusion (OCTs and some OCTNs), (2) anion exchangers (OATs), and (3) some Na+/zwitterion cotransporters (OCTNs). They participate in small intestinal absorption and hepatic and renal excretion of drugs, xenobiotics and endogenous compounds and perform homeostatic functions in the brain and heart. Important endogeneous substrates include monoamine neurotransmitters, l-carnitine, alpha-ketoglutarate, cAMP, cGMP, prostaglandins and urate. Mutations in the SLC22 genes cause specific diseases like primary systemic carnitine deficiency and idiopathic renal hypouricemia and are correlated with diseases such as Crohn's disease and gout. Drug-drug interactions at individual transporters may change pharmacokinetics and toxicities of drugs (Koepsell 2013). Models of Octs resemble GLUT3 (PDB ID# 5C65) and have an intracellular three/four-helix loop between TMH6 and TMH7 containing putative phosphorylation sites for precise regulation of hOCTs. The models allow prediction of substrate binding sites (Dakal et al. 2017). Interactions with therapeutic herbal products, dietary supplements, and clinically important drugs are discussed, and the significance of these transporters in modulating the severity of drug-related side effects and toxicity mechanisms have been reviewed (Mor et al. 2018). OCTs are highly expressed on the plasma membranes of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives) (Samodelov et al. 2020). SLC22 is a family of drug/metabolite exporters (i.e., OAT1) speicific for (1) drugs and natural products, (2) antibiotics (i.e., cefazolin) and antiviral agents (i.ie., adefovir), (3) chemo-theraputic agents (i.e., methotrexate), (4) antioxidants (i.e., uric acid) that decrease oxidative stress and aging, (5) protaglandins (i.e., PG F2a), (6) gut microbial metabolites (i.e., hippuric acid and trimethylamine oxide, TMAO),  (7) other compounds including bile acids (Granados et al. 2021; Zhang et al. 2021). Their functions are similar in flies and mammals.


TC#NameOrganismal TypeExample

The basolateral multivalent, potential-sensitive, organic cation (tetramethyl-ammonium; N'-methylnicotinamide; cationic drugs, xenobiotics, vitamins, neuro-transmitters, etc.) transporter (uni-porter)-1, Oct1.  Cysteyl residues essential for transport and substrate binding have been identified (Sturm et al. 2007). Subtype-specific affinity of rat organic cation transporters rOCT1 and rOCT2 for corticosterone depends on three amino acids within the substrate binding region (Gorboulev et al. 2005). Differences in metformin and thiamine uptake between human and mouse Oct1 transporters have been demonstrated (Meyer et al. 2020).


Oct1 of Rattus norvegicus (Q63089)


The apical proximal tubular kidney/placenta organic anion transporter 4, Oat4 (Slc22a11) (transports estrone sulfate (Km = 1 µM), dehydroepiandrosterone sulfate (Km = 60µM), many anionic drugs, diuretics, bile salts, urate and ochratoxin A). Catalyzes Na+-independent efflux, possibly using glutamate as a counter anion in an exchange reaction, especially in the placenta (Lofthouse et al. 2015).  Functions in renal urate reabsorption (Prestin et al. 2014). Chlorine decreases the expression of the gene encoding this transporter (Suman et al. 2023). hOAT4 is mainly expressed in the kidney and placenta, and is essential for the disposition of numerous drugs, toxins, and endogenous substances. It is regulated by insulin-like growth factor and portein kinase B (Yu et al. 2023).


SLC22A11 (Oat4) of Homo sapiens


The apical proximal tubular renal urate:anion exchanger, URAT1 (Slc22a12).  Catalyzes Na+-independent anion efflux (secretion) and reabsorption (Eraly et al., 2003a,b; Anzai and Endou, 2011; Prestin et al. 2014)  Regulated by the PDZK1 protein; Anzai et al., 2004). Also transports orotate, a precursor of pyrimidine biosynthesis (Miura et al., 2011). Mutations in URAT1 cause hereditary renal hypouricemia/gaut.  Residues involved in urea and inhibitor binding have been identified (Tan et al. 2016). Mutations can cause renal hypouricemia (RHUC), a heterogeneous genetic disorder that is characterized by decreased serum uric acid concentrations and increased fractional excretion of uric acid (Zhou et al. 2018; Kaynar et al. 2022). Mutation in transmembrane domain 8 of the human urate transporter 1 (residue K393) disrupts uric acid recognition and transport (Lan et al. 2022). Pathogenic variants of SLC22A12 (URAT1) and SLC2A9 (GLUT9) can give rise to renal hypouricemia (Perdomo-Ramirez et al. 2023). Biphenyl carboxylic acid derivatives are potent URAT1 inhibitors (Hou et al. 2023).


URAT1/SLC22A12 of Homo sapiens


The high affinity L-carnitine transporter, CT2, present in the luminal membranes of epididymal epithelia and Sertoli cells of the testis (Enomoto et al., 2002b).  It also catalyzes uptake of the anticancer polyamine analogue, bleomycin-A5 (Aouida et al. 2010). Carnitine transport and metabolism have been reviewed (Nałęcz and Nałęcz 2017). SLC22A16 (CG6126) transports ergothioneine (Zhang et al. 2021).


SLC22A16 of Homo sapiens


The organic cation transporter, Oct1 (transports L-carnitine; expressed in vascular tissues of various organs and at sites of lateral root formation) (Lelandais-Briere et al, 2007). It also transports spermine and other polyamines and is induced by them (Sagor et al. 2016).  It protects against the polyamine, cadaverine, which affects root length (Strohm et al. 2015).


Oct1 of Arabidopsis thaliana (Q9CAT6)


Brush border glycosylated urate (Km= 1.2 mM) tranporter, RST. Orthologous to the human URAT1. Inhibited by 50 μM benzbromarone, 1 mM probenecid and 10 mM lactate which may also be transported and trans-stimulate urate uptake. May be orthologous to 2.A.1.19.11 as well (Hosoyamada et al., 2004).  Involved in urate absorption across the apical membrane, but probably not the primary route (Eraly et al. 2008; Prestin et al. 2014).


RST/Slc22a12 of Mus musculus

2.A.1.19.15The liver multispecific organic anion transporter, NLT or OAT2. Transports salicylate, KM=90µM, acetylsalicylate, prostaglandin E2, dicarboxylate, p-aminohippurate, etc. (Sekine et al., 1998)AnimalsNLT of Rattus norvegicus (Q63314)

The organic anion transporter, Oat6 or SLC22a20 of 556 aas and 12 TMSs.  Binding and transport rates for 40 anionic substrates have been studied and compared with those for Oat1 (TC# 1.A.1.19.4) (Kaler et al., 2007). Oat6 transports many antiviral agents (Truong et al., 2008). It can bind odorants and is present in the mouse olfactory mucosa; it has been proposed to be an odorant receptor and/or odorant transporter (Wu et al. 2015). Mouse OAT6 is expressed predominantly in olfactory mucosa but not in kidney or brain (Monte et al. 2004).


Oat6 of Mus musculus (Q80UJ1)


Kidney organic cation transporter-like 3 ORCTL-3 (OAT10; SLC22A13; Like-3) (Bahn et al., 2008) (transports nicotinate, p-aminohippurate and urate; KM=20-40 mμM) via exchange for lactate).  Activated by tumorigeneic mutations in this antitumor gene to promote apoptosis (AbuAli and Grimm 2014).  Functions in urate reabsorption (Prestin et al. 2014). Substrate binding and lipid-mediated allostery in the human organic anion transporter 1 have been examined at the atomic-scale (Janaszkiewicz et al. 2023).


SLC22A13 of Homo sapiens

2.A.1.19.18Oranic anion transporter, Oat7 (exchanges sulfate conjugates (steroids) and other anions for butyrate) (Shin et al., 2007)AnimalsSLC22A9 of Homo sapiens

The rat kidney basolateral potential-driven symport carrier, Oct2 (transports tetraethylammonium and many other organic cations) (Sweet and Pritchard 1999).  A cysteyl residue critical for substrate binding and transport has been identified (Sturm et al. 2007). Subtype-specific affinity of rat organic cation transporters rOCT1 and rOCT2 for corticosterone depends on three amino acids within the substrate binding region (Gorboulev et al. 2005).


Oct2 of Rattus norvegicus (Q9R0W2)


The ergothionine/carnitine/hydroxyurea/organic zwitterion transporter, OCTN1 or SVOP (SLC22A4). It is upregulated in polycythemia vera hematopoietic stem and progenitor cells (Tan and Meier-Abt 2021). It is associated with rheumatoid arthritis (Barton et al., 2005).  Acetylcholine is a physiological substrate, and its transport could be involved in nonneuronal cholinergic functions (Pochini et al. 2013).  OCTN1 and OCTN2 are associated with several pathologies, such as inflammatory bowel disease, primary carnitine deficiency, diabetes, neurological disorders, and cancer. It transports TEA, and transoirts acetylcholine better than acetylcarnitine (Pochini et al. 2015).


SLC22A4 (OCTN1) of Homo sapiens (O14546)


Prostaglandin (PGE2, PGE2α, and PGD(2)) -specific organic anion transporter. Exhibits Na+ -independent and saturable transport. Shows narrow substrate selectivity and high affinity (Shiraya et al., 2010). 


Slc22a22 (OAT-PG) of Mus musculus (Q8R0S9)

2.A.1.19.21 solute carrier family 22, member 24AnimalsSLC22A24 of Homo sapiens

solute carrier family 22, member 14, Slc22a14, is crucial for sperm motility and male fertility in mice. It is expressed specifically in male germ cells, and mice lacking the Slc22a14 gene show severe male infertility as well as sperm morphological changes (Maruyama et al. 2016).


SLC22A14 of Homo sapiens

2.A.1.19.23 solute carrier family 22, member 31AnimalsSLC22A31 of Homo sapiens

Solute carrier family 22 member 3 (Extraneuronal monoamine transporter) (EMT) (Organic cation transporter 3) of 556 aas and 12 TMSs.  Induction of astrocytic Slc22a3 (EMT) regulates sensory processing through histone serotonylation (Sardar et al. 2023).


SLC22A3 of Homo sapiens


Solute carrier family 22 member 7 (liver transporter) (Organic anion transporter 2) (hOAT2), transports cyclic nucleotodes and the anti-viral drug, acyclovir (Dahlin et al. 2013). Expressed mostly in liver, but also in kidney, brain and red blood cells (Sager et al. 2018). slc22 transporter homologs in flies, worms, and humans clarify the phylogeny of organic anion (OATs) and cation (OCTs) transporters (Eraly et al. 2004).


SLC22A7 of Homo sapiens


SLC22 OAT ortholog, Multispecific anion transporter, oat-1 (George et al. 1999)


oat-1 of Caenorhabditis elegans

2.A.1.19.27Solute carrier family 22 member 10 (Organic anion transporter 5)AnimalsSLC22A10 of Homo sapiens

Solute carrier family 22 member 23.  The rat orthologue may be inactive (Bennett et al. 2011). Human SLC22A23 is expressed in many tissues including brain (brain organic cation transporter (BOCT2) (Bennett et al. 2011).


SLC22A23 of Homo sapiens


Solute carrier family 22 member 1 (Organic cation transporter 1) (hOCT1).  May be a primary polyamine uptake porter (Abdulhussein and Wallace 2013). Amino acids in TMS1 confer major functional differences between human and mouse orthologs of the polyspecific membrane transporter, OCT1. Reduced function alleles of OCT1 associate significantly with high LDL cholesterol levels (Yee et al. 2023).


SLC22A1 of Homo sapiens


The polyspecific organic cation (L- and D-carnitine, butyryl-L-carnitine, acetyl carnitine, γ-butyro-betaine, glycinebetaine, β-lactam antibiotics with a quaternary nitrogen such as cephaloridine, and others):Na+ symporter, OCTN2 (SLC22A5). Carnitine is transporter with high affinity (2 - 20 μM0 (Ingoglia et al. 2015). Associated with Crohn''s disease (Barton et al., 2005) as well as primary carnitine deficiency.  The protein is glycosylated on extracytoplasmic asparagines, and these residues are in a region important for function and turnover (Filippo et al. 2011).  OCTN2 maintains the carnitine homeostasis, resulting from intestinal absorption, distribution to tissues, and renal excretion/reabsorption (Pochini et al. 2013).  OCTN1 and OCTN2 are associated with several pathologies, such as inflammatory bowel disease, primary carnitine deficiency, diabetes, neurological disorders, and cancer.  OCTN2 is activated in a process dependent on Caveolin1 (Q03135) which interacts directly with OCTN2 and by protein kinase C which does not phosphorylate OCTN2 directly (Czeredys et al. 2013). Cholesterol stimulates the cellular uptake of L-carnitine by the carnitine/organic cation transporter novel 2 (OCTN2) (Zhang et al. 2020). A dataset of OCTN2 variant functions and localization has been created, revealing important disease-causing mechanisms (Koleske et al. 2022).  Primary carnitine deficiency (PCD) is caused by pathogenic variants of the SLC22A5 gene, which encodes a high affinity carnitine transporter. Carnitine is essential for the transport of acyl-CoA, produced from fatty acids, into the mitochondria where they are oxidised to produce energy (Khries et al. 2023). OctN2 transports doxorubicin (Yi et al. 2023). A novel pathogenic variant in the carnitine transporter gene, SLC22A5, is associated with metabolic carnitine deficiency and cardiomyopathy features (Jolfayi et al. 2024).


SLC22A5 (OCTN2) of Homo sapiens


Solute carrier family 22 member 2 (Organic cation transporter 2) (hOCT2).  Oct2 is a low affinity high efficiency choline transporter, enriched in synaptic vesicles of cholinergic neurons (Nakata et al. 2013).  May also transport peptides and peptide derivatives (Volková et al. 2015). It also transports L-carnitine (Adeva-Andany et al. 2017). OCT2 is a multispecific transporter with cholesterol-dependent allosteric features. The role of cholesterol recognition/interaction amino acid consensus sequences (CRAC and CARC) in the allosteric binding to 1-methyl-4-phenylpyridinium (MPP+) has been reported (Sutter et al. 2021). Comparisons of the inhibitory potential of elacridar and imazalil on metformin uptake with that on MPP uptake revealed substrate-dependent differences in hOCT2 and mOct2 for both inhibitors (Kuehne et al. 2022).


SLC22A2 or Oct2 of Homo sapiens


Solute carrier family 22 member 6 (Organic anion transporter 1) (hOAT1) (PAH transporter) (hPAHT) (Renal organic anion transporter 1) (hROAT1),  Probably orthologous to 2.A.1.19.4. Functions in urate uptake from the circulation across the basolateral membrane of tubular cells (Prestin et al. 2014).  It transports methotrexate (anticancer), acyclovir (antiviral), and adefovir (antiviral) (Nigam 2015).


SLC22A6 of Homo sapiens


Solute carrier family 22 member 15 (Fly-like putative transporter 1) (Flipt 1). This system is required for hepatocellular carcinoma proliferation and metastasis (Fang et al. 2021). SLC22A15 (FLIPT1) prefers zwitterionic compounds over cations and anions. Eight zwitterions transported include ergothioneine, carnitine, carnosine, gabapentin, as well as four cations including MPP+ , thiamine and cimetidine. Carnosine was a specific substrate of SLC22A15 among the transporters in the SLC22A family. SLC22A15 transport was sodium-dependent and exhibited higher Km values for ergothioneine, carnitine, and carnosine compared to previously identified transporters for these ligands (Yee et al. 2020). Many carnitine derivatives (i.e., (R)-3-hydrixybutryl carnitine, hexanoyl carnitine and glutaryl carnitine amoung others) are also transported.


SLC22A15 of Homo sapiens


Solute carrier family 22 member 25 (Organic anion transporter UST6).  Expressed exclusively in liver in both embryo and adult (Eraly et al. 2004). It may take up a nucleobase-containing compound (Meixner et al. 2020).


SLC22A25 of Homo sapiens


Multispecific drug transporter, solute carrier family 22 member 8 (Organic anion transporter 3) (hOAT3).  Both OAT1 and OAT3 of humans are inhibited by caffeic acid (Ki ~ 17 μM) (Uwai et al. 2011; Wu et al. 2013).  It is the principal uptake system for steviol glucuronide (SVG), the major metabolite derived from steviol, the aglycone of stevioside and rebaudioside A (Wang et al. 2015).  Also functions in urate uptake from the circulation across the basolateral membrane of renal tubular cells (Prestin et al. 2014). Inhibition of the proteasome, but not the lysosome, upregulates organic anion transporter 3 (Fan et al. 2022). See also 2.A.1.19.9.


SLC22A8 of Homo sapiens


Solute carrier family 22 member 20 (Organic anion transporter 6; OAT6) of 555 aas and 12 probable TMSs. This protein is an apparent anionic odorant transporter in the olfactory epithelium of mice (Monte et al. 2004; Kaler et al. 2006).


SLC22A20 of Homo sapiens


Organic cation transporter-like protein, OrcT, of 548 aas and 12 TMSs (Taylor et al. 1997).


OrcT of Drosophila melanogaster


Organic cation transporter 1 (CeOCT1) of 568 aas and 12 TMSs.  It transports tetraethylammonium ions and has broad substrate specificity (Wu et al. 1999).


Oct-1 of Caenorhabditis elegans

2.A.1.19.38Uncharacterized MFS-type transporter PB1E7.08cYeastSPAPB1E7.08c of Schizosaccharomyces pombe
2.A.1.19.39Organic cation/carnitine transporter 6 (AtOCT6)PlantsOCT6 of Arabidopsis thaliana

The polyspecific organic anion, cation and neutral molecule transporter, Oat1 (Slc22a6) (transports neutral compounds such as cardiac glycosides [i.e., ouabain] and steroids [i.e., aldosterone; cortisol; dexamethasone]; cationic compounds such as N-propylajmalinium, and anionic compounds such as p-aminohippurate, dicarboxylates, cyclic nucleotides, prostaglandins, urate, β-lactam antibiotics, nonsteroidal anti-inflammatory drugs, diuretics, bile salts and steroid conjugates [i.e., estrone-3-sulfate and estradiol-17-glucuronide]) transporter (H+ symporter or uniporter) Probably catalyzes organic anion (uptake):dicarboxylate (efflux) antiport in the basolateral membrane of kidney proximal tubules) (Eraly et al., 2003a,b). A 3-dimensional model of OAT1 has led to the identification of residues involved in differential transport of substrates such as p-aminohippurate and cidofovir (Perry et al., 2006). Oat1 transports many antiviral agents (Truong et al., 2008).  The human orthologue (Q4U2R8; 563aas) has been shown to be a multispecific organic anion transporter on the basolateral membrane of the proximal tubule in human kidney (Hosoyamada et al. 1999). A substrate binding hinge domain is required for transport-related structural changes (Egenberger et al., 2012). Transports environmental toxins and clinically important drugs including anti-HIV therapeutics, anti-tumor drugs, antibiotics, anti-hypertensives, and anti-inflammatories (Duan et al., 2011). hOAT1 has two GXXXG motifs in TMSs 2 and 5 which play critical roles in stability (Duan et al., 2011).  Both OAT1 and OAT3 of humans are inhibited by caffeic acid (Ki ~ 17 μM) (Uwai et al. 2011).


Oat1 of Rattus norvegicus (O35956)


Organic anion transporter, Oat9.  A splice variant with 443 aas and 8 TMSs (Oa9S) was reported to transport L-carnitine (3 μM), cimetidine (16 μM) and salicylic acid (175 μM), but the full length protein of 551 aas and 12 TMSs (Oat9L) was reported to be inactive (Tsuchida et al. 2010).  


Oat9 of Mus musculus


Organocation transporter, OCTN3.  Identified only in mouse; mediates carnitine transport (Pochini et al. 2013).  81% identical to 2.A.1.19.3.  Also called SLC22a21 and SLC22a9.


OctN3 of Mus musculus


Slc22 homologue of 580 aas.

Plants (single celled marine green alga)

Slc19 homologue of Ostreococcus tauri


Organocation transporter, Oct4 of 526 aas and 12 TMSs.  It is induced under drought conditioins.


Oct4 of Arabidopsis thaliana (Mouse-ear cress)


Uncharacterized protein of 556 aas

Plants (Algae)

UP of Chlorella variabilis (Green alga)


MFS transporter of 569 aas


MFS transporter of Tetrahymena thermophila


MFS transporter of 593 aas

Alveolata (ciliates)

MFS porter of Oxytricha trifallax


MFS porter of 691 aas


MFS porter of Volvox carteri (Green alga)


Fungal MFS homologue of 520 aas


UP of Aspergillus terreus


Putative glucose transporter 1 (Gluct1) of 569 aas and 12 TMSs.  Constitutively synthesized in many tissues.  Serves as the receptor of white spot syndrom virus (WSSV) (Huang et al. 2012). 


Gluct1 of Litopenaeus vannamei (Whiteleg shrimp) (Penaeus vannamei)


The putative apical polyspecific organic cation transporter (cation:H+ or cation:cation antiporter), Oct2 (substrates include monoamine neurotransmitters such as dopamine, noradrenaline, adrenaline and 5-hydroxytryptamine) (Oct2 exhibits some properties of an ion channel with an inner diameter of ~4 Å. Selectivity: Cs+ > Rb+ > K+ > Na+ %u2248 Li+ (Schmitt and Koepsell, 2005)) Chloride dependent, but a single mutation (R466K) abolishes this dependency (Rizwan et al., 2007). Also transports ochratoxin (Rizwan et al., 2007) and cisplatin and oxaliplatin (Yonezama et al., 2006).

AnimalsOct2 of Sus scrofa (O02713)

Uncharacterized solute carrier family 22 member 15-like of 543 aas and 12 TMSs (Posavi et al. 2020).

UP of Eurytemora affinis


The polyspecific potential-sensitive organic cation uptake transporter, Oct3 (transport substrates include the neurotoxin 1-methyl-4-phenylpyridinium and monoamine neurotransmitters such as dopamine). Mediates paraquat (herbicide) neurotoxicity (Rappold et al., 2011). SLC22 transporters involved in drug elimination and organ distribution are polyspecific. The cryo-EM structure of SLC22A3 (OCT3) is available (Meyer-Tönnies and Tzvetkov 2023).


Oct3 of Rattus norvegicus (O88446)

2.A.1.19.7The polyspecific organic anion (and cation) (anions: p-aminohippurate, ochratoxin A, estrone sulfate, anionic drugs, anionic neurotransmitter metabolites; cation: cimetidine) transporter, Oat3 (slc22a8) (catalyzes organic anion (uptake): dicarboxylate (efflux) antiport in the basolateral membrane of the renal proximal tubule) (Eraly et al., 2003a,b); transports many antiviral agents (Truong et al., 2008).AnimalsOat3 of Rattus norvegicus (Q9R1U7)

The human organic cation transporter, SLC22A17.  The rat orthologue may be inactive (Bennett et al. 2011). It is also the cell surface receptor for Lipocalin-2 (LCN2) that plays a key role in iron homeostasis and transport. It is able to bind iron-LCN2, followed by internalization and release of iron, thereby increasing intracellular iron concentration and leading to inhibition of apoptosis (Cabedo Martinez et al. 2016). It also binds iron-free LCN2, followed by internalization and its association with an intracellular siderophore, leading to iron chelation and iron transfer to the extracellular medium, thereby reducing intracellular iron concentrations and resulting in apoptosis.  The SLC22A17/lipocalin-2 receptor plays a role in renal endocytosis of proteins involved in metalloproteins, particularly on iron- and cadmium-binding proteins (Thévenod et al. 2023).  Other renal functions of SLC22A17 include its contribution to osmotic stress adaptation, protection against urinary tract infection, and renal carcinogenesis.


SLC22A17 of Homo sapiens


The osteosclerosis protein, Roct (organic anion transporter 3, Oat3) (Slc22a8) (catalyzes organic anion (uptake):di-carboxylate (efflux) antiport in the basolateral membrane of the renal proximal tubule) (Eraly et al., 2003a,b); transports glutathione and many antiviral agents (Truong et al., 2008).  It is a multispecific drug transporter, critical for the renal handling of common drugs (e.g, antibiotics, antivirals, diuretics) and toxins.  Probably handles hydroxylated and glucouronidated metabolites, consistent with the "remote sensing and signaling hypothesis" (Wu et al. 2013).  It may also handle dietary flavonoids and antioxidants.


Roct (Oat3) of Mus musculus (O88909)


TC#NameOrganismal TypeExample

2.A.1.2 The Drug:H+ Antiporter-1 (12 Spanner) (DHA1) Family


TC#NameOrganismal TypeExample

Pyridoxine, pyridoxal, pyridoxamine, amiloride:H+ cotransporter (Km (pyridoxine) = 22 μM) (Stolz et al., 2005). Also takes up thiamine (Vogl et al., 2008).


Bsu1 (Car1) of Schizosaccharomyces pombe (P33532)


Quinolone (and other drug):H+ antiporter, NorA.  Many synthetic inhibitors have been identified (Bhaskar et al. 2016). 1,8-Naphthyridines sulfonamides are NorA efflux pump inhibitors (Oliveira-Tintino et al. 2021).


NorA of Staphylococcus aureus (P0A0J7)


Bcr/CflA family drug resistance efflux transporter of 389 aas and 12 TMSs. Multidrug-resistance in S. aureus is inhibited by the endocannabinoid, anandamide (Sionov et al. 2022).  Butyrolactone I enhances the efficacy of gentamycin in methicillin-resistant S. aureus (Jiang et al. 2024).

MDR exporter of Staphylococcus aureus


Bmr-like protein SblA of 395 aas and 12 TMSs.

SblA of Staphylococcus aureus


TetA class C (TetA(C)) of 396 aas and 12 TMSs. The TetA(C) of the transposon, Tn10, not only exports tetracycline by a proton antiport mechanism, it also increases susceptibility to cadmium, fusaric acid, bleomycin and  several classes of cationic aminoglycoside antibiotics (Griffith et al. 1995).  For this reason, it has been used to generate dual counter selection procedures (Li et al. 2013). It is not certain that this is due to import of these compounds as this increased susceptibility could be due to a secondary effect.

TetA(C) of E. coli


Tetracycline:H+ class D, (TetA(D)) antiporter of 286 aas and 12 TMSs.

TetA(D) of E. coli


MFS carrier of 490 aas and 12 TMSs, MfsD14a or Hiat1 (Hippocampus abundant transcript 1 protein) is a member of the SLC18 family.  It is 76% identical to 2.A.1.2.30. Mutant mice (Mus musculus, strain 129S6Sv/Ev) were generated with the Mfsd14a gene disrupted with a LacZ reporter gene. Mutant mice are viable and healthy, but males are sterile due to a 100-fold reduction in the number of spermatozoa in the vas deferens. Male mice have adequate levels of testosterone and show normal copulatory behaviour. The few spermatozoa that are formed show rounded head defects similar to those found in humans with globozoospermia. Spermatogenesis proceeds normally up to the round spermatid stage, but the subsequent structural changes associated with spermiogenesis are severely disrupted with failure of acrosome formation, sperm head condensation and mitochondrial localization to the mid-piece of the sperm. Mfsd14a expression occurs in Sertoli cells, suggesting that MFSD14A may transport a solute from the bloodstream that is required for spermiogenesis (Doran et al. 2016). MFSD14A and MFSD14B are intracellular neuronal membrane-bound proteins, expressed in the Golgi and ER, and their levels of expression are affected by both starvation and a high fat diet to varying degrees in the mouse brain (Lekholm et al. 2017). It is associated with milk production in buffalo and sheep breeds, as well as growth of chickens and goats, and drastically affect s sperm morphogenesis (Luo et al. 2023). The functional InDel polymorphism (rs1089950828) reflects growth traits in domestic sheep populations (Luo et al. 2023).

MfsD14a of Homo sapiens


MFSD9 of 474 aas and 12 TMSs. In the mouse, this protein and MFS4a localize to neurons in the brain; their mRNA expression levels are affected by diet (Perland et al. 2017). This protein is in the SLC18 family (Gyimesi and Hediger 2022).

MFSD9 of Homo sapiens


Uncharacterized MFS-type transporter YvmA

BacilliyvmA of Bacillus subtilis

MFS porter of 399 aas and 12 TMSs, HepP, involved in the uptake of glycoside(s), with a specific physiological role in production of heterocyst exopolysaccharide, HEP (López-Igual et al. 2012).

HepP of Anabaena or Nostoc sp. (strain PCC 7120)


Putative spermine uptake porter of 552 aas and 12 TMSs, SPBC409.08.  Spermine and the spermine-precursor, spermidine, are implicated in ageing as they are involved in autophagy-dependent lifespan extension (Ellis et al. 2018).

SPBC409.08 of Schizosaccharomyces pombe


MFS porter of 414 aas and 12 TMSs.  It has been suggested that it could be a citrate efflux porter (Braakman et al. 2017).

MFS porter of Prochlorococcus marinus

2.A.1.2.11Monoamine transporter; drug (doxorubicin, ethidium bromide-6-G):H+ antiporterAnimalsVMAT1 of Rattus norvegicus

Florfenicol-chloramphenicol resistance drug exporter, FloR of 404 aas and 12 TMSs (Braibant et al. 2005). This system in V. cholerae (98.8% identical) exports chlorampenicol (Saha et al. 2024).

FloR of Salmonella enterica subsp. enterica serovar Typhimurium str. DT104


Zinc-induced facilitator-like protein 1, ZIFL1 or Tpo1p  of 478 aas and 12 TMSs. It confers resistance to the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D) and is transcriptionally activated in response to this herbicide. Tpo1p is required to reduce the intracellular concentration of 2,4-D (Cabrito et al. 2009). K+ may be its physiological substrate, and it may play a dual role in polar auxin transport and drought stress tolerance (Remy et al. 2013). It is also involved in auxin efflux and acts as a positive regulator of shootward transport at the root apex. Possibly, it may mediate proton efflux from the vacuolar compartment (Remy et al. 2013).

Tpo1 of Arabidopsis thaliana


Uncharacterized protein of 904 aas with 16 TMSs in a 6 + 6 + 3 + 1 TMS arrangement, where the last 300 aas comprise the non-MFS integral membrane domain with at least 4, and maybe as many as 6 TMSs. May possibly play a role in lipid transport.

UP of Aspergillus ruber


Uncharacterized MFS transporter of 539 aas and 11 TMSs.  It is probably similar in sequence to MfsT, described as a penicillin G (isopenicillin N) precursor in Monascus ruber (Ramzan et al. 2019).

MFS porter of Aspergillus clavatus


MFS1 of 728 aas and 12 TMSs. The MFS1 transporter contributes to Penicilliun digitatum fungicide resistance and fungal virulence during citrus fruit infection (de Ramón-Carbonell et al. 2019).

MFS1 of Penicillium digitatum


Multidrug resistance MDR exporter of 583 aas and 12 TMSs. It is involved in resistance to the antifungal drugs miconazole, tioconazole, clotrimazole and ketoconazole as well as to quinidine   (Costa et al. 2013; Costa et al. 2016).  It also plays a role in biofilm formation. Compared to the wild type, the C. glabrata ∆qdr2 mutant showed lower adhesion activity and higher fluconazole susceptibility when assessed as a biofilm. The mutant also showed decreased metabolic activity during biofilm formation and grew more slowly under neutral-basic pH conditions. The qdr2 deletion in C. glabrata resulted in an impaired ability to maintain pH homeostasis, which led in turn to a reduction of cell growth and of adherence to an artificial matrix (Widiasih Widiyanto et al. 2019). Mitochondrion-targeted antifungal drugs have been reviewed (Qin et al. 2023).

MDR pump of Candida glabrata (Yeast) (Torulopsis glabrata)


MDR efflux pump, Bcr/CflA, of 411 aas and 12 TMSs.  Confer's chloramphenicol resistance (Yang et al. 2019).

Brc of Myxococcus xanthus


Uncharacterized protein of 510 aas and 12 TMSs.

UP of Fistulifera solaris


Na+ (K+ or Li+)/H+ antiporter and multidrug:Na+ anitporter, MdrP of 424 aas and 12 TMSs.  It exports ethidium and norfloxacin in exchange for Na+ taken up (Abdel-Motaal et al. 2018). D223  acts as a key determinant in the Na+ translocation coupled to norfloxacin efflux (R. Zhang, Abdel-Motaal et al, 2020).

MdrP of Planococcus maritimus


AaMFS1 is an efflux pump for the transmembrane transport of tenuazonic acid (TeA) (Sun et al. 2022).  See 4.C.1.1.19 for relevant information about the TeA synthetase that makes TeA before exporting it (Sun et al. 2022). The genes encoding these two proteins are adjacent to each other.

MFS1 of Alternaria alternata


Chromaffin granule monoamine (and drug) transporter, VAT1. It is involved in the transport of biogenic monoamines such as serotonin from the cytoplasm into the secretory vesicles of neuroendocrine and endocrine cells (Essand et al. 2005). It is strongly inhibited by reserpine, and to a lesser extent by ketanserin and fenfluramine, but not by tetrabenazine (Erickson et al. 1996).  Fine-tuning novel monoamine reuptake inhibitor selectivities has been acieved through manipulation of inhibitor stereochemistry (chirality) (Kalaba et al. 2023).


SLC18A1 of Homo sapiens


Major Familitator, MFS6 of 550 aas and 12 TMSs in a 6 + 6 TMS arrangement with a central ~ 200 aa hydrophilic domain. The substrate is not known (Wichers et al. 2022).

MFS6 of Plasmodium malariae


MFS permease of 550 aas and 12 TMSs in a 6 + 6 TMS arrangement with a large central hydrophilic domain betweem residues 200 and 370.

MFS permease of Plasmodium ovale (malaria parasite P. ovale)


MfsC (Smlt0549), a probable diamide exporter of 379 aas and 12 TMSs in a 6 + 6 TMS arrangement.  It is encoded within the mfsBC operon controlled by the DitR TetR-like transcript factor which binds diamide to displace the repressing factor from the DNA. MfsB (BeFL18) may be a sugar uptake porter (Boonyakanog et al. 2022).

MfsC of Stenotrophomonas maltophilia


Fluconazole resistance protein 1, Flu1 of 610 aas and 12 TMSs. It mediates resistance to structurally and functionally unrelated compounds including cycloheximide but also azoles such as fuconazole, ketoconazole and itraconazole (Calabrese et al. 2000). It mediates efflux of histatin 5, a salivary human antimicrobial peptide, and is responsible for reduction of its toxicity in C.albicans (Li et al. 2013, Hampe et al. 2017).

Flu1 of Candida albicans


Putative MDR pump, MDT; MFS1, of 442 aas and 12 TMSs (Wunderlich 2022).

MDR pump of Plasmodium falciparum


MFS drug-resistance efflux pump of 401 aas and 12 TMSs.  This system exports tetracycline and doxycycline and is induced by several drugs in addition to these compounds (Li et al. 2023).

SAUSA300_09310 of Staphylococcus aureus


MFS permease of 405 aas and 12 TMSs, KpsrMFS (He et al. 2024). This efflux pump is a proton-driven transporter that can reduce the intracellular tetracycline concentration. In normal conditions, the expression of kpsrmfs was at a low level, while artificial overexpression of it led to increased endogenous reactive oxygen species (ROS) production. By comparing the functions of adjacent genes of kpsrmfs, another four genes that can confer similar phenotypes, indicating a special regulon that regulates cell growth.. 

KpsrMFS of Klebsiella pneumoniae


Vesicular acetylcholine:H+ antiporter, UNC-17/VAChT.  Mutants grow slowly and are uncoordinated, but the defects can be corrected by mutation of two interacting monotopic protein, synaptobrevin-1/SNB-1 (109 aas and 1 C-terminal TMS; Sandoval et al. 2006) and SUP-1 (103 aas and 1 C-terminal TMS (Mathews et al. 2012).


Unc17 of Caenorhabditis elegans


Putative arabinose efflux porter, AraJ.


AraJ of E. coli


Arabinose (but not xylose) and isopropyl β-D-thio-galactopyranoside:H+ antiporter, YdeA (Koita and Rao 2012). Overexpression of the gene for YdeA allows export of Lacto-N-triose (LNT II) and lacto-N-tetraose (LNT), human milk oligosaccharides (Sugita and Koketsu 2022).


YdeA of E. coli


Polyamines (spermine, spermidine, putrescine); paraquat; methylglyoxal bis(guanylhydrazone):H+ antiporter (in the plasma membrane) (activated by phosphorylation) (Uemura et al., 2005)


TPO1 (YLL028w) of Saccharomyces cerevisiae

2.A.1.2.17Fluconazole:H+ antiporterYeastFlr1 of Saccharomyces cerevisiae
2.A.1.2.18Lactose and melibiose (>>IPTG) efflux pump, SotBBacteriaSotB of Erwinia chrysanthemi

The multidrug (chloramphenicol, tetracycline, norfloxacin, doxorubicin, trimethoprim, acriflavin, ethidium bromide, tetraphenylphosphonium, TPP, benzalkonium, ciprofloxacin, thiamphenicol, IPTG) resistance exporter, MdfA (catalyzes both electrogenic and electroneutral transport) (Adler and Bibi, 2004). Can function as a Na+ (K+)/H+ antiporter (Lewinson and Bibi 2001; Higgins, 2007). Is known to provide resistance to a wide variety of dissimilar toxic compounds, including neutral, cationic and zwitterionic substances.  Crystals that diffracted to 3.4 Å resolution and belonged to the hexagonal space group P6122 have been obtained (Nagarathinam et al. 2017). For review of MdfA see Lewinson et al., 2006. The conformational switch accompanying transport is induced by the promiscuous binding of substrates and/or inhibitors to the binding pocket (Fluman et al., 2009). MdfA normally extrudes monovalent cationic drugs in exchange for a single proton, but it transports divalent cationic drugs poorly. It can be mutated to antiport a divalent cationic drug for 2 protons (Tirosh et al., 2012). Transporters acting across the inner and outer membranes have synergistic effects with each other, but transporters acting across the same membrane are usually additive but can be synergistic under special circumstances, owing to a bifurcation controlled by the barrier constant (Saha et al. 2020). Promiscuity in the geometry of electrostatic interactions between  MdfA and cationic substrates has been demonstrated (Adler and Bibi 2005). With respect to ethidium bromide, the inner membrane transporter MdfA is synergistic to the TolC-dependent efflux across the outer membrane (Saha et al. 2020). The conformational behavior of MdfA in response to substrate binding has been studied (Bahrenberg et al. 2021). Overexpression of the gene for MdfA allows export of Lacto-N-triose (LNT II) and lacto-N-tetraose (LNT), human milk oligosaccharides (Sugita and Koketsu 2022).


MdfA of E. coli (P0AEY8)

2.A.1.2.2Cycloheximide:H+ antiporterYeastCyhR of Candida maltosa

Broad specificity MDR efflux pump, MdtG (YceE) (under SoxSR control) (Fàbrega et al., 2010).  Confer resistance to fosfomycin, fluoroquinolone and many other drugs (Nishino and Yamaguchi 2001).


MdtG of E. coli


The norfloxacin/enoxacin resistance protein, MdtH or YceL (Nishino and Yamaguchi 2001).


MdtH or YceL of E. coli (P69367)


The multidrug resistance protein, YidY (Nishino and Yamaguchi 2001).


YidY of E. coli

2.A.1.2.23The fructose-specific facilitator (uniporter), Ffz1 (Pina et al., 2004)YeastFfz1 of Zygosaccharomyces bailii (CAD56485)
2.A.1.2.24The multidrug resistance efflux pump, CgMDR (exports fluoroquinolones and chloramphenicol) (Vardy et al., 2005)BacteriaCgMDR of Corynebacterium glutamicum (NP_600365)

The purine base/nucleoside (nucleosides: inosine, adenosine and guanosine; bases: hypoxanthine, adenine, guanine, 2-fluoroadenine) efflux pump, YdhL (PbuE) (Johansen et al., 2003; Nygaard and Saxild, 2005; Zakataeva et al., 2007; Sheremet et al. 2011).


PbuE of Bacillus subtilis (O05504)


The purine ribonucleoside (inosine, adenosine, guanosine, 6-mercaptopurine ribonucleoside) efflux pump (H+ antiporter), NepI (YicM) (Gronskiy et al., 2005; Sheremet et al. 2011)


NepI of E. coli (P0ADL1)

2.A.1.2.27The alcaligin siderophore exporter, AlcS (Brickman and Armstrong, 2005)BacteriaAlcS of Bordetella pertussis (CAE42734)

The vesicular acetylcholine transporter, VAChT (pumps acetylcholine into synaptic vesicles).  The acetyl choline and vesamicol binding sites have been identified (Ojeda et al. 2004) and are near the luminal end of the transport pathway (Khare et al. 2010). The SLC18 family has been reviewed (Lawal and Krantz 2018). VAChT in the brain is an important presynaptic cholinergic biomarker (Hu et al. 2023).


SLC18A3 of Homo sapiens


The vesicular monoamine transporter, VMAT2 (pumps dopamine, norepinephrine, serotonin and histamine into synaptic vesicles) (Cliburn et al. 2016). VMAT2 physically and functionally interacts with the enzymes responsible for dopamine synthesis (Cartier et al., 2010).  Molecular hinge points mediating alternating access have been identified (Yaffe et al. 2013). The substituted amphetamine, 3,4-methylenedioxy-methamphetamine (MDMA, ecstasy), is a widely used drug of abuse that induces non-exocytotic release of serotonin, dopamine, and norepinephrine through their cognate transporters as well as blocking the reuptake of neurotransmitter by the same transporters (Sealover et al. 2016). The slc18a2 gene is expressed at high levels in neuroepithelial cells (Pan et al. 2022). Synaptic vesicle proteins are selectively delivered to axons in mammalian neurons (Watson et al. 2023). VMAT2 may play a role in Parkinson's disease (Zhou et al. 2023). Dopaminergic cell protection and alleviation of neuropsychiatric disease symptoms are aleviated by VMAT2 expression (Lee et al. 2023).


VMAT2 (SLC18A2) of Homo sapiens


Chloramphenicol:H+ antiporter, CmlA; Cmr; MdfA.  Multidrug exporter that also catalyzes efflux of arabinose (but not xylose) and  isopropyl β-thiogalactoside (Koita and Rao 2012).


CmlA of Pseudomonas aeruginosa


The hippocampus abundant transcript-like 1 protein, HIATL1 or MFSD14B, of 506 aas and 12 TMSs (putative drug exporter) is a SLC18 family member. There is a correlation between a risk for colorectal cancer, alcohol consumption and variants in the 9q22.32/HIATL1 gene (Gong et al. 2016). MFSD14A (HIAT1) and MFSD14B (HIATL1) are in the mouse central nervous system throughout the adult brain (Lekholm et al. 2017). Expression of SLC22A18 regulates oxaliplatin resistance (Kim et al. 2022), and in cases of oxaliplatin resistance due to low SLC22A18 expression, resistance can be overcome by treatment with an ERK inhibitor (Kim et al. 2022). Two ammonia transporters, HIAT1alpha and HIAT1beta, in the American Horseshoe Crab, Limulus polyphemus, have been identified and characterized (Sachs et al. 2022). This gene is associated with milk production in buffalo and sheep breeds, as well as growth of chickens and goats, and drastically affect sperm formation (Luo et al. 2023). The functional InDel polymorphism (rs1089950828) reflects growth traits in domestic sheep populations (Luo et al. 2023).


HIATL1 of Homo sapiens (NP_115947)


The multidrug transporter, QDR2, required for resistance to quinidine, barban, cisplatin, and bleomycin; may play a role in potassium uptake.


QDR2 of Saccharomyces cerevisiae (P40474)

2.A.1.2.32The chloramphenicol resistance protein, ChlRBacteriaChlR of Streptomyces lividans (P31141)
2.A.1.2.33The Hol1 MFS transporter (Mutation allows the uptake of histidinol and other cations (Wright et al., 1996). The N-terminal 200 residues show 22% identity with 2.A.1.2.1 and 2.A.1.2.16).YeastHol1 of Saccharomyces cerevisiae (P53389)

The MDR efflux pump, PmrA (exports fluoroquinolone and other compounds) and other components including the antimicrobial peptide, colistin (Martinez-Garriga et al. 2007; Pamp et al., 2008).


PmrA of Streptococcus pneumoniae (P0A4K4)


The caffeine resistance protein 5 (Caf5) (Benko et al., 2004)


Caf5 of Schizosaccharomyces pombe (O94528)

2.A.1.2.36The multidrug resistance protein Aqr1 (YNL065w) (exports short chain monocarboxylates but not more hydrophobic acids such as octonate and quinidine. Also exports ketoconazole and crystal violet (Tenreiro et al., 2002)).YeastAqr1 of Saccharomyces cerevisiae (P53943)
2.A.1.2.37The legiobactin (siderophore) exporter (most similar to 2.A.1.2.9; 23% identity) (Allard et al., 2006)Gram-negative bacteriumIbtB of Legionella pneumophila
LbtA (Q45RG2)
LbtB (Q5WX21)
2.A.1.2.38Tetracycline-specific exporter, TetA39 (most like 2.A.1.2.4) (Thompson et al., 2007).BacteriaTetA39 of Acinetobacter spp. (Q56RY7)
2.A.1.2.39Tetracycline-specific exporter, TetA41 (most like 2.A.1.2.4) (Thompson et al., 2007).BacteriaTetA41 of Serratia marcescens (Q5JAK9)
2.A.1.2.4Tetracycline:H+ antiporterBacteriaTetA of E. coli
2.A.1.2.40The dityrosine exporter, Dtr1 (required for formation of the outer layer of the cell wall (Morishita and Engebrecht, 2008)).


Dtr1 of Saccharomyces cerevisiae (P38125)

2.A.1.2.41The tetracycline resistance determinant, TetA42 from a deep terrestrial subsurface bacterium (Brown et al., 2008).


TetA42 of Micrococcus sp. SMCC G8878 (B2YGG2)


The multidrug efflux pump, EmrD-3 (exports ethidium, linezolid, tetraphenylphosphonium chloride, rifampin, erythromycin, minocycline, trimethoprim, chloramphenicol, and rhodamine) (Smith et al., 2009).


EmrD-3 of Vibrio cholerae (Q9KMQ3)


The multidrug efflux pump, Qdr3 (exports polyamines, quinidine, barban, cisplatin and bleomycin). The two halves of the protein each have an N-terminal. 150 residue hydrophilic region found in many fungi followed by a 200 residue, 6 TMS, transmembrane region. This suggests that an intragenic duplication event gave rise to 12 TMS proteins independently of most other MFS carriers, but this has not been demonstrated, possibly because of extensive sequence divergence of the second half.


Qdr3 of Saccharomyces cerevisiae (P38227)


Diglucosyl-diacylglycerol exporter or flippase, LtaA (lipoteichoic acid protein A) (Gründling and Schneewind, 2007).


LtaA of Staphylococcus aureus (Q2FZP8)


The fructose-specific uniporter, Ffz1 (69% identical to Ffz2 
(2.A.1.2.46) and 66% identical to (2.A.1.2.23) (Leandro et al., 2011). 


Ffz1 of Zygosaccharomyces rouxii (C5E4Z7)


The fructose/glucose uniporter, Ffz2 (64% identical to 2.A.1.2.23). Both sugars are transported with similar affinities and efficiencies (Leandro et al., 2011). 


Ffz2 of Zygosaccharomyces rouxii (C5DX43)


The multidrug resistance efflux pump, HsMDR (YfmO2).  Exports drugs such as fluoroquinolones and chloramphenicol (Vardy et al., 2005).


HsMDR of Halobacterium salinarum


tetracycline exporter


tetR exporter of Aspergillus niger (A2QTF4)


Putative tetracycline resistance protein


Putative tet resistance pump of Pyrobaculum aerophilum (Q8ZUX8)


Multidrug (14- and 15-membered macrolides, lincosamides, streptogramins, tetracyclines, daunomycin, ethidium bromide, etc.):H+ antiporter, LmrP. Two proton translocation pathways have been proposed (Bapna et al., 2007), but Schaedler and van Veen, 2010 have provided evidence that a flexible cation binding site in LmrP is associated with variable proton coupling. Basic residues R260 and K357 affect the conformational dynamics of LmrP (Wang and van Veen, 2012).  Basic residues, R260 and K357 control the conformational dynamics of the protein (Wang and van Veen 2012).  Also specifically catalyzes Ca2+:3H+ antiport with an affinity of 7 μM (Zhang et al. 2012). Two carboxylates (Asp-235 and Glu-327) are critical for Ca2+ binding.  Protonation drives major conformational switches (Masureel et al. 2013). The system exhibits plasticity in proton interactions, which is a consequence of the flexibility in the location of key residues that are responsible for proton/multidrug antiport (Nair et al. 2016).


Gram-positive bacteria

LmrP of Lactococcus lactis


MFS porter

Slime molds

MFS porter of Dictyostelium purpureum (F0ZU09)


Chloramphenicol resistance pump, CraA (43% identical to MdfA of E. coli) (Roca et al., 2009). It is a broad specificity transporter exporting chloramphenicol, thiamphenicol, florfenicol, ethidium, dequalinium, chlorhexidine, benzalkonium, mitomycin C and TPP+. Glu-38 is essential for activity (Foong et al. 2019).


CraA of Acinetobacter baumannii (A3M9E9)


Puromycin resistance MDR protein, MdtM (Soo et al., 2011).  Also catalyzes bile salt:H+ antiport, and binds cholate and deoxycholate to the protein with micromolar affinity. Functions as an MDR pump (Nishino and Yamaguchi 2001). Acts synergistically with AcrAB-TolC (Paul et al. 2014). The ortholog has been characterized in Salmonella enterica serovar Typhi, and specific residues have been shown to be important for transport and stability (Shaheen et al. 2021).


MdtM of E. coli (P39386)


MDR pump, SLC22A18 in lung cancer cells (Lei et al., 2012). It has 424 aas and 12 TMSs. Allelic loss in the absence of mutations in the polyspecific transporter gene BWR1A on 11p15.5 in hepatoblastoma has been shown (Albrecht et al. 2004).


SLC22A18 of Homo sapiens


LigA-like protein


LigA-like protein of Streptomyces coelicolor (Q9KYE9)


Peptide exporter (Ala-Gln and Ala-branched chain amino and dipeptides) (Hayashi et al., 2010).  May also export arabinose (but not xylose) and function as an MDR pump (Koita and Rao 2012).


YdeE of E. coli (P31126)


NCL7 or MFSD8. Neuronal ceroid lipofuscinosis, NCL, a neuro-degenerative genetic disease, is caused by mutations in at least 8 different human genes, one of which, CLN7 (MFSD8), is associated with late infantile NCL. CLN7 is localized to lysosomes (Sharifi et al., 2010).  Loss of this putative lysosomal transporter in the brain leads to lysosomal dysfunction, impaired constitutive autophagy and neurodegeneration late in the disease (Brandenstein et al. 2015). An in-frame deletion in the MFSD8 gene gave rise to neuronal ceroid lipofuscinosis type 7 (Hosseini Bereshneh and Garshasbi 2018). In D. discoideum, it interacts with cathepsin D (CtsD), as well as human orthologs of CLN3 (Cln3) and CLN5 (Cln5) (Huber et al. 2020). In humans the defect can also affect cardiac conducting cells and cardiomyocytes as well as basophilic degeneration of myocardium. (Iannaccone Farkašová et al. 2019).  Moreover, loss of Mfsd8 alters the secretome during Dictyostelium aggregation (Huber et al. 2023).


NCL7 of Homo sapiens (Q8NHS3)


MFS-type polyamine transporter SLC18B1 or VPAT (Solute carrier family 18 member B1) of 456 aas and 12 TMSs.  Polyamines synthesized in neurons and astrocytes are stored in secretory vesicles and released upon depolarization. Vesicular storage is mediated in an ATP-dependent, reserpine-sensitive process.  SLC18B1 is the fourth member of the SLC18 transporter family, which includes vesicular monoamine transporters and a vesicular acetylcholine transporter. Proteoliposomes containing purified human SLC18B1 protein actively transport spermine and spermidine in exchange of H+. The SLC18B1 protein is predominantly expressed in the hippocampus and is associated with vesicles in astrocytes. SLC18B1 gene knockdown decreased both the amount of the SLC18B1 protein and the spermine/spermidine contents of astrocytes (Hiasa et al. 2014).  Slc18b1 knock out mice have reduced polyamine content in the brain These mice have impaired short and long term memory in novel object recognition, radial arm maze and self-administration paradigms (Fredriksson et al. 2019). Moreover, Slc18b1 KO mice have altered expression of genes involved in Long Term Potentiation, plasticity, calcium signalling and synaptic functions, and expression of components of GABA and glutamate signalling are alterred. These mutants show partial resistance to diazepam, manifested as lowered reduction in locomotion after diazepam treatment. Possibly, removal of Slc18b1 leads to reduction of polyamine contents in neurons, resulting in reduced GABA signalling due to a long-term reduction in glutamatergic signalling (Fredriksson et al. 2019).  Polyamine release and vesicular polyamine transporter, SLC18B1; VPAT,. expression in megakaryoblastic cells and plateletshas been documented (Uehara et al. 2024).


C6orf192 of Homo sapiens

2.A.1.2.58Protein ZINC INDUCED FACILITATOR 1PlantsZIF1 of Arabidopsis thaliana

Uncharacterized MFS-type transporter C330.07c; YJ87


YJ87 of Schizosaccharomyces pombe


(Benomyl, cycloheximide, methotrexate, fluconazole, etc.):H+ antiporter, CaMDR1 (Basso et al., 2010; Cannon et al., 1998). MDR1 catalyzes efflux of commonly used azoles. The central cytoplasmic loop is critical for MDR function, but does not impart substrate specificity (Mandal et al., 2012). The structural basis for polyspecificity of MDR MFS transporters, based on studies with Mdr1, is the extended capacity brought by residues located at the periphery of a binding core to accomodate compounds differing in size and type (Redhu et al. 2018). Each domain in the protein is arranged in a pseudo-symmetric fold of two tandems of 3-TMSs that alternatly expose the drug-binding site towards the inside or the outside of the yeast to promote drug binding and release. Sharma et al. 2022 provided information on these motifs by having screened a library of 64 drug transport-deficient mutants and their corresponding suppressors spontaneously addressing the deficiency. They found that five strains recovered the drug-resistance capacity by expressing CaMdr1 with a secondary mutation. The pairs of debilitating/rescuing residues are distributed either in the same TMS or 3-TMS repeat, at the hinge of 3-TMS repeat tandems, and between the N- and C-domains. Most of these mutants belong to different signature motifs, highlighting a mechanistic role and interplay thought to be conserved among MFS proteins. Results point to the specific role of TMS 11 in the interplay between the N- and C-domains in the inward- to outward-open conformational transition (Sharma et al. 2022).


CaMDR1 of Candida albicans


YajR of 454 aas and 12 TMSs.  The 3-D structure in the outward-facing conformation is available at 3.15Å resolution, and the cytoplasmic C-terminal YAM domain has been solved to 1.07Å resolution.  This 65 aa YAM domain is thought to control the conformational states of the protein (Jiang et al. 2013; Jiang et al. 2014).


YajR of E. coli


SPX domain-containing membrane protein At1g63010, called Vacuolar Phosphate Transporter 1 (VPT1), It transports phosphate > sulphate > nitrate > chloride and malate.  The vpt1 mutant plants were stunted and consistently retained less Pi than wild type plants, especially when grown in medium containing high levels of Pi. In seedlings, VPT1 was expressed primarily in younger tissues under normal conditions, but was strongly induced by high-Pi conditions in older tissues, suggesting that VPT1 functions in Pi storage in young tissues and in detoxification of high Pi in older tissues. As a result, disruption of VPT1 rendered plants hypersensitive to both low-Pi and high-Pi conditions, reducing the adaptability of plants to changing Pi availability (Liu et al. 2015).


VPT1 or At1g63010 of Arabidopsis thaliana


Putative MDR pump, YdhC or PunC.  It has been reporte to export arabinose but not xylose (Koita and Rao 2012). However, it also takes up adenosine, adenine, deoxyadenosine, and other purine nucleosides and nucleobases such as inosine and guanosine as sole nitrogen sources. It also takes up various sulfonamides such as sulfathiazole, sulfadiazine and sulfamethoxazole.  Expression of the punC gene is reglulated by the positive transcription factor, PunR (YdhB) (Rodionova et al. 2021).


PunC (YdhC) of Escherichia coli

2.A.1.2.63Probable drug/proton antiporter YHK8FungiYHK8 of Saccharomyces cerevisiae

Polyamine exporter 4 (Igarashi and Kashiwagi 2010).


TPO4 of Saccharomyces cerevisiae


Inner membrane transport protein YdhP


YdhP of Escherichia coli


Polyamine exporter 3 (Igarashi and Kashiwagi 2010).


TPO3 of Saccharomyces cerevisiae


Polyamine exporter 2 (Igarashi and Kashiwagi 2010).


TPO2 of Saccharomyces cerevisiae


Tetracycline resistance protein, class B (TetA(B)) (Metal-tetracycline/H+ antiporter).  Mutants defective in either transport or tetracycline binding have been isolated (Wright and Tate 2015). Several amino acid substitutions (i.e., D190C, E192C and S201C) alter the specificity of the porter so that it prefers deoxycycline (3x) and minochcline (6x) over tetracycline (Sapunaric and Levy 2005).


TetA of Escherichia coli


Uncharacterized MFS-type transporter YttB


YttB of Bacillus subtilis


Bicyclomycin, sulfathiazole, tetracycline, fosfomycin, acriflavin, etc.):H+ antiporter (Nishino and Yamaguchi 2001).  Also exports L-cysteine (Yamada et al., 2006).

Gram-negative bacteria

Bcr of E. coli

2.A.1.2.70Multidrug resistance protein 1 (Multidrug-efflux transporter 1)Bacilli

Bmr of Bacillus subtilis

2.A.1.2.71Uncharacterized MFS-type transporter Rv2456c/MT2531BacteriaRv2456c of Mycobacterium tuberculosis
2.A.1.2.72Major facilitator superfamily domain-containing protein 9AnimalsMfsd9 of Mus musculus

Major facilitator superfamily domain-containing protein 10, MFSD10, a member of the SLC18 family. It is a tetracycline exporter-like protein.  This protein is found in the inner nuclear membrane (Cheng et al. 2019) and is a disease protein in humans (Bagchi et al. 2020). Its gene shows increased expression with increased energy consumption (Bagchi et al. 2020). It may confers cellular resistance to apoptosis induced by the non-steroidal anti-inflammatory drugs, indomethacin and diclofenac. A microdeletion proximal to the mfsD10 gene is associated with mild Wolf-Hirschhorn syndrome (Hannes et al. 2012).



MfsD10 of Mus musculus

2.A.1.2.74Multidrug resistance protein MdtL


MdtL of Shewanella sp.

2.A.1.2.75Tetracycline resistance protein, class E (TetA(E))


TetA of Escherichia coli


Major facilitator copper transporter 1, Mfc1.  Takes up copper in meiotic sporulating cells; present in the forespore membrane.  Induced under copper limitation.  Required for normal forespore development and spore copper-dependent amine oxidase activity (Beaudoin et al. 2011).


Mfc1 of Schizosaccharomyces pombe


CefT confers phenylacetate resistance (Fernández-Aguado et al. 2012).  It has been reported to be a hydrophilic beta-lactam transporter that is involved in the secretion of hydrophilic beta-lactams containing an α-aminoadipic acid side chain (isopenicillin N, penicillin N and deacetylcephalosporin C) (Cesareo et al. 2007; Ullán et al. 2002).


CefT of Acremonium chrysogenum


The PaaT (PenT) exporter.  PaaT is involved in penicillin production, possibly through the translocation of side-chain precursors (phenylacetate and phenoxyacetate) from the cytosol to the peroxisomal lumen across the peroxisomal membrane of P. chrysogenum.  It has a Pex19 (peroxisome biogenesis factor 19) binding sequence (residues 258 - 269) accounting for its peroxysomal location (Fernández-Aguado et al. 2012; Yang et al. 2012).


PaaT of Penicillum chysogenum (notatum)


The host-nonselective polyketide perylenequinone toxin, cercosporin, exporter, Ctb4 (Choquer et al. 2007).


Ctb4 of Cercospora nicotianae


(Spermidine; fluoroquinolones, acriflavin, chloramphenicol, ethidium bromide, etc.):H+ antiporter (Woolridge et al. 1997).

Gram-positive bacteria

Blt of Bacillus subtilis


Putative permease of 458 aas


Putative permease of Galdieria sulphuraria


Uncharacterized MFS permease; encoded by a gene adjacent to one encoding a peroxiredoxin (an electron donor and antioxidant; Hanschmann et al. 2013).


UP of Deinococcus peraridilitoris


Uncharacterized MFS permease of 402 aas and 12 TMSs


UP of Leptospira interrogans


MmrA MFS protein. Homologous to drug exporter. RppA and MmrA are involved in amino acid uptake and efflux of antimicrobial agents including streptomycin, ethidium bromide and norfloxacin (Kimura et al. 2004).


MXAN_5906 of Myxococcus xanthus.  


Probable siderophore-specific exporter of 407 aas and 12 TMSs, MxcK.


MxcK of Stigmatella aurantiaca


Peroxysomal phenylacetate/phenoxyacetate transporter, PaaT (CefT) of 564 aas (Fernández-Aguado et al. 2013).


PaaT of Penicillium chrysogenum (Penicillium notatum)


Peroxisomal isopenicillin N importer, PenM (Evers et al. 2004; Fernández-Aguado et al. 2014).


PenM of Penicillium chrysogenum (Penicillium notatum)


Purine efflux porter of 392 aas, CepA.  Exports purine analogues, 6-mercaptopurine and 6-mercaptoguanine, but not to 2-aminopurine and purine nucleoside analogues. May show increased resistance to the antibiotics nalidixic acid and ampicillin (Sim et al. 2014).


CepA of Corynebacterium glutamicum


MFS porter of 442 aas


MFS porter of Pyrococcus furiosus


MFS porter of 454 aas


MFS porter of Streptomyces coelicolor


(Hydrophobic uncoupler e.g., CCCP, benzalkonium, SDS and other drugs):H+ antiporter, EmrD (Nishino and Yamaguchi 2001). The 3-d structure (3.5 Å resolution) has been determined (Yin et al., 2006).  conformational dynamics studies have revealed details of the transport pathway and some motions of EmrD at an atomic level (Baker et al. 2012).  Probably exports arabinose but not xylose (Koita and Rao 2012).

Gram-negative bacteria

EmrD of E. coli


UMF4F of 405 aas and 12 TMSs


UMF4F of Aectobacterium woodii


MFS permease of 554 aas and 12 TMSs


Putative MFS carrier of Metarhizium robertsii (Metarhizium anisopliae)


The CefM protein of 482 aas and 12 TMSs. Probably involved in the translocation of penicillin N from the lumen of peroxisomes (or peroxisome-like microbodies) to the cytosol, where it is converted into cephalosporin C (Teijeira et al. 2009).  A null mutant accumulates  penicillin N, is unable to synthesize deacetoxy- and deacetyl-cephalosporin C as well as cephalosporin C, and shows impaired differentiation into arthrospores (Teijeira et al. 2009).

CefM of Acremonium chrysogenum (Cephalosporium acremonium)


Uncharacterized MFS permease of 433 aas and 12 TMSs

UP of Lactobacillus buchneri


Uncharacterized MFS permease of 445 aas and 12 TMSs

UP of Microbacterium maritypicum


Blt of 422 aas and 12 TMSs.  Exports antibiotics such as fluoroquinolones and chloramphenicol (Vardy et al. 2005)

Blt of Mycobacterium smegmatis


ZIF2 (Zinc-Induced Facilitator 2) of 484 aas and 12 TMSs localises primarily at the tonoplast of root cortical cells and is a functional transporter able to mediate Zn efflux from the cytoplasm (Remy et al. 2014).  Activity is controlled by alternative RNA splicing. 

ZIF2 of Arabidopsis thaliana


Bcr/CflA family drug exporter, MSMEG_2991 of 428 aas and 12 TMSs. A pmf-dependent multidrug efflux pump that expels diverse groups of antibiotics including ciprofloxacin. May also be involved in biofilm enhancement (Bansal et al. 2016).

Bcr-like exporter of Mycobacterium smegmatis


Uncharacterized MFS transporter of 427 aas and 12 TMSs.

UP of Aeropyrum camini


Putative siderophore exporter, SbnD of 418 aas and 12 TMSs (Marklevitz and Harris 2016).

SbnD of Staphylococcus aureus


2.A.1.20 The Sugar Efflux Transporter (SET) Family


TC#NameOrganismal TypeExample

Sugar efflux transporter A, SetA.  Exports lactose, glucose, aromatic glucosides and galactosides, cellobiose, maltose, α-methylglucoside and isopropyl β-thiogalactosides (IPTG); amino-glycosides, streptomycin and kanamycin are weakly expelled (Liu et al. 1999).  Regulated by SgrR (a transcriptional regulator of sgrS) and SgrS (a small RNA that represses trascription of setA).  These two regulatory genes are upstream of the setA gene.  Uses a pmf-dependent mechanism of energization.  Induced in response to glucose-phosphate stress which occurs when a sugar phosphates accumulate in the cytoplam (Sun and Vanderpool 2011). Overexpression of the gene for SetA allows export of Lacto-N-triose (LNT II) and lacto-N-tetraose (LNT), human milk oligosaccharides (Sugita and Koketsu 2022).


SetA (YabM) of E. coli


Sugar efflux system, SetB, for lactose and glucose, but not IPTG or galactose (Liu et al. 1999). Overexpression of the gene for SetB allows export of Lacto-N-triose (LNT II) and lacto-N-tetraose (LNT), human milk oligosaccharides (Sugita and Koketsu 2022).


SetB (YeiO) of E. coli


Arabinose (but not xylose) exporter, SetC (Koita and Rao 2012).


SetC (YicK) of E. coli

2.A.1.20.4Efflux system for arabinose and IPTG (>>lactose), SotA BacteriaSotA of Erwinia chrysanthemi

2.A.1.21 The Drug:H+ Antiporter-3 (12 Spanner) (DHA3) Family


TC#NameOrganismal TypeExample

The macrolide (erythromycin; oleandomycin; azithromycin; telithromycin) efflux pump, MefA, of 405 aas and 12 TMSs (Cantón et al. 2005; Bley et al. 2011). Iannelli et al. 2018 suggested that MefA can function with an ATPase, MsrD (TC# 3.A.1.121.6), and therefore function as an ABC drug exporter.  However, the data presented seem inconsistent with this suggestion. The two genes encoding these two proteins are adjacent to each other, suggesting that they may function together (Iannelli et al. 2018). Predicted transmembrane proteins with homology to MefA do not complement a mefA deletion in the MefA-MsrD macrolide efflux system in Streptococcus pneumoniae (Fox et al. 2021). Note: MsrD is an ATPase of the ABC superfamily, so it can not be certain that MefA and MsrD function together. Coupling of an MFS carrier with an ABC-type energizer is very rare, maybe non-existent.


MefA of Streptococcus pyogenes


MFS porter


MFS porter of Sulfolobus islandicus (D2PCQ8)


MFS porter


MFS porter of Stackebrandtia nassauensis (D3Q871)


Multidrug-efflux transporter, Rv1258c/MT1297, of 419 aas and 12 TMSs. Both Rv1634 and Rv1258c are believed to play major roles in drug resistance by altering the protein pump that is required to remove the active drugs from the bacterial cell (Panja et al. 2019).


Rv1258c of Mycobacterium tuberculosis

2.A.1.21.13Uncharacterized MFS-type transporter yjbBBacilli

YjbB of Bacillus subtilis

2.A.1.21.14Uncharacterized MFS-type transporter Mb0038cActinobacteriaMb0038c of Mycobacterium bovis

MFS Homologue


MFS homologue of Streptomyces coelicolor (Q9X9Y0)


MFS Homologue


MFS homologue of Streptomyces coelicolor (Q9X8T4)


Uncharacterized MFS-type transporter YxaM


YxaM of Bacillus subtilis


Uncharacterized protein


Uncharacterized protein of Streptomyces coelicolor


Uncharacterized Major Facilitator


UMF of Streptomyces coelicolor


The multidrug (erythromycin, tetracycline, puromycin, bleomycin) resistance protein, Cmr


Cmr of Corynebacterium glutamicum


Unidentified Major Facilitator


UMF of Pseudomonas syringae


Unidentified major facilitator


UMF of Saccharomonospora marina


Macrolide efflux pump, MefE (Mef; MefA) of 405 aas.  Induced by erythromycin and the antimicrobial peptide, LL-37 (Zähner et al. 2010).  May act in conjunction with Mel (Q93QE4), an ABC-type ATPase that is encoded in the same operon with the mefA gene (Ambrose et al. 2005).


MefE of Streptococcus pneumoniae


Uncharacterized MFS permease of 433 aas and 12 TMSs

UP of Deinococcus geothermalis


MFS_1 protein of 476 aas and 12 TMSs.

MFS_1 of Bifidobacterium longum

2.A.1.21.3The tetracycline resistance determinant, TetV BacteriaTetV of Mycobacterium smegmatis
2.A.1.21.4Multidrug resistance efflux pump, Tap BacteriaTap of Mycobacterium fortuitum
2.A.1.21.5The putative bacilysin exporter, BacEBacteriaBacE of Bacillus subtilis (P39642)
2.A.1.21.6The tetracycline resistance efflux pump, TetA(P) (Bannam et al., 2004) (21% identity (e-07) with 2.A.1.21.5 and 22% identity (2xe-7) with 2.A.1.2.10). It may be the link between DHA1 and DHA3.


TetA (P) of Clostridium perfringens (Q46305)


The Staphyloferrin A (siderophore) exporter, NWMN-2081 (Beasley et al. 2009). Independently suggested to be a macrolide exporter (Marklevitz and Harris 2016).


NWMN-2081 of Staphylococcus aureus (A6QJ21)


The putative macrolide exporter, TIGR00900 (most similar to 2.A.1.21.1).


TIGR00900 of Bacillus clausii (Q5WAS7)


MFS carrier of unknown function


MFS carrier of Thermoplasma acidophilum (Q9HLP1)


2.A.1.22 The Vesicular Neurotransmitter Transporter (VNT) Family (Related to the SP Family (TC #2.1.1))


TC#NameOrganismal TypeExample

Synaptic vesicle glycoprotein neurotransmitter (e.g., dopamine) transporter, SV2A or SLC22B1.  This protein localizes to neurotransmitter-containing vesicles and has a nucleotide binding site (Yao and Bajjalieh 2009). The SV2 family is comprised of three paralogues: SV2A, SV2B, and SV2C. They are present in secretory vesicles, including synaptic vesicles, and are critical to neurotransmission. Structural and functional studies suggest that SV2 proteins may play several roles to promote proper vesicular function. Among these roles are their potential to stabilize the transmitter content of vesicles, to maintain and orient the releasable pool of vesicles, and to regulate vesicular calcium sensitivity to ensure efficient, coordinated release of the transmitter (Stout et al. 2019). SV2A plays a role in neuronal excitability and as such is the specific target for the antiepileptic drug levetiracetam as well as seletracetam and brivaracetam. SV2 proteins also act as the target by which potent neurotoxins, particularly botulinum, gain access to neurons and exert their toxicity. Both SV2B and SV2C are increasingly implicated in diseases such as Alzheimer's disease and Parkinson's disease. Despite decades of intensive research, their exact functions were elusive in 2019 (Stout et al. 2019), but the systems may transport galactose.The human (Q70J3) and rat orthologs are 99% identical. The structure, function, and disease relevance of GP2 (SV2) transporters have been reviewed (Stout et al. 2019).  More than one percent of people have epilepsy worldwide. Levetiracetam (LEV) is a successful new-generation antiepileptic drug (AED), and its derivative, brivaracetam (BRV), shows improved efficacy. Synaptic vesicle glycoprotein 2a (SV2A), a membrane transporter in the synaptic vesicles (SVs), has been identified as a target of LEV and BRV. SV2A also serves as a receptor for botulinum neurotoxin (BoNT) (Yamagata et al. 2024).  The structural basis for antiepileptic drugs and botulinum neurotoxin recognition of SV2A have been ellucidated (Yamagata et al. 2024).


SV2 of Rattus norvegicus


Synaptic vesicle glycoprotein 2B of 556 aas


Glycoprotein 2B of Tribolium castaneum


AgaP of 537 aas

Animals (Insects)

AgaP of Anopheles gambiae


Uncharacterized protein of 537 aas


UP of Acyrthosiphon pisum


Uncharacterized protein of 561 aas


UP of Trichoplax adhaerens (Trichoplax reptans)


Synaptic vesicle 2C, SV2C or SLC22B3, of 727 aas and 11 TMSs. Botulinum neurotoxins (BoNTs) inhibit neurotransmitter release by selectively cleaving core components of the vesicular fusion machinery. The synaptic vesicle proteins Synaptotagmin-I and -II act as receptors for BoNT/B and BoNT/G. Mahrhold et al. 2006 showed that BoNT/A also interacts with a synaptic vesicle protein, the synaptic vesicle glycoprotein 2C (SV2C), but not with the homologous proteins SV2A and SV2B. Binding of BoNT/A occurs at the membrane juxtaposed region preceding transmembrane domain 8. A peptide comprising the intravesicular domain between transmembrane domains 7 and 8 specifically reduces the neurotoxicity of BoNT/A at phrenic nerve preparations, demonstrating the physiological relevance of this interaction (Mahrhold et al. 2006). The interactions of SV2C with BoNT have been reviewed (Li et al. 2020). SV2C is implicated in diseases such as Alzheimer's disease and Parkinson's disease (Stout et al. 2019). It seems to play roles in vesicle trafficking, exocytosis and neurotransmission (Hu et al. 2017).

SV2C of Homo sapiens


Synaptic vesicle glycoprotein 2B, SV2B or SLC22B2, of 683 aas and 12 TMSs in a 6 +  1 + 5 TMS arrangement.  SV2B, ephrin B1 and the receptors of angiotensin II are expressed in the podocyte, and their expressions were altered in anti-nephrin antibody-induced nephropathy. These proteins may be involved in the development of proteinuria (Kawachi et al. 2009). SV2B and SV2C may be involved in the pathogenesis of epilepsy as well as other neurodegenerative diseases (Löscher et al. 2016) such as Alzheimer's disease and Parkinson's disease (Stout et al. 2019). Defective lysosomal acidification may provide a prognostic marker and therapeutic target for neurodegenerative diseases (Lo and Zeng 2023).

SV2B of Homo sapiens


2.A.1.23 The Conjugated Bile Salt Transporter (BST) Family


TC#NameOrganismal TypeExample

Conjugated bile salt:H+ symporter, CbsT1 of 452 aas and 12 TMSs. Its gene is in an operon with those for CbsT2 and CbsH, a conjugated bile salt hydrolase, and such operons are common amoung the lactobacilli including Lactobacillus acidophilus (Elkins et al. 2001).


CbsT1 of Lactobacillus johnsonii 100-100


Taurocholate:cholate antiporter, CbsT2 of 451 aas and 12 TMSs (Elkins and Savage 2003).


CbsT2 of Lactobacillus johnsonii 100-100 (AAC34380)


2.A.1.24 The Vacuolar Basic Amino Acid Transporter (VBAAT) Family


TC#NameOrganismal TypeExample
2.A. KDa protein, YCL038c YeastYCL038c of Saccharomyces cerevisiae

Vacuolar amino acid (Arg, Lys, His) transporter, Atg22 (Autophagy-related protein-22) (Sugimoto et al. 2011).


Atg22 of Schizosaccharomyces pombe (Q09812)


MFS permease


MFS permease of Chloroflexus aurantiacus (A9WGR7)


MFS permease


MFS permease of Myxococcus xanthus (Q1CWQ3)


MFS permease


MFS permease of Micrococcus luteus (Micrococcus lysodeikticus)


MFS porter of 474 aas


MFS porter of Hyphomonas neptunium


Uncharacterized MFS carrier protein of 524 aas.

UP of Entamoeba histolytica


2.A.1.25 The Peptide/Acetyl-Coenzyme A/Drug Transporter (PAT) Family


TC#NameOrganismal TypeExample

The endoplasmic reticular/Golgi acetyl-CoA:CoA antiporter 1, ACATN/ACATN1 (SLC33A1).  Allows acetylation of sialic acid residues in gangliosides and lysine residues in membrane proteins.  It is associated with neurodegenerative disorders such as sporadic amyotrophic laterial sclerosis (ALS) and Spastic Paraplegia 42, and it is essential for motor neuron viability (Hirabayashi et al. 2013). Abnormal concentrations of acetylated amino acids in cerebrospinal fluid are observed in acetyl-CoA transporter deficiency (Šikić et al. 2022).


SLC33A1 of Homo sapiens


Cell wall degradation product (peptides and glycopeptides including N-acetylglucosaminyl β-1,4-anhydro-N-acetyl-muramyl-tri or tetra-peptide) as well as penicillin derivative uptake porter, AmpG (Cheng and Park 2002). The AmpG permease is also required for AmpC beta-lactamase induction (Chahboune et al. 2005; Park and Uehara 2008). AmpG mediates a dynamic relationship between serine beta-lactamase induction and biofilm-formation (Mallik et al. 2018).


AmpG of E. coli (P0AE16)


The AmpG peptidoglycan degradation product uptake porter is part of the peptidoglycan recycling pathway (Garcia and Dillard, 2008). It also plays a role in peptidoglycan remodeling, recycling, and toxic fragment release as well as pathogenesis (Schaub and Dillard 2019).


AmpG of Neisseria gonorrhoeae (Q5F6G0)


Putative peptide/acetyl-CoA transporter of 560 aas and 12 TMSs.

Uncharacterized protein of Saccharomyces cerevisiae (Baker's yeast)


Transporter of meuropeptides, N-acetylglucosamine anhydrous N-acetylmuramyl peptides, AmpG (Kong et al. 2010).  Necessary for induction of ampC, β-lactamase, and ampicillin resistance (Zhang et al. 2010). Amino acyl residues essential for proper mRNA production and for catalytic activity have been identified (Li et al. 2016).


AmpG of Pseudomonas aeruginosa


Uptake transporter, AmpG, of 433 aas and 12 TMSs, specific for muropeptides, fragments of the peptidoglycan cell walls of bacteria (Ruscitto et al. 2017).

AmpG of Tannerella forsythia


Putative acetyl-CoA:CoA antiporter, ACT or AT1, of 590 aas and 12 or 13 TMSs in a 6 or 7 + 6 TMS arrangement (Wunderlich 2022).

ACT lf Plasmodium falciparum


2.A.1.26 The Drug:H+ Antiporter-4 (DHA4) Family Family


TC#NameOrganismal TypeExample
2.A. KDa Protein, YcaD BacteriaYcaD of E. coli

MFS porter, YfkF; possible drug exporter


YfkF of Bacillus subtilis (O34929)


Multidrug resistance efflux porter, BC3310 of 396 aas and 12 TMSs.  Exports ethidium bromide, sodium dodecyl sulfate and silver nitrate.  D105 in TMS4 is essential for activity (Kroeger et al. 2015).

BC3310 of Bacillus cereus


2.A.1.27 The Phenyl Propionate Permease (PPP) Family


TC#NameOrganismal TypeExample

The phenylpropionate porter, HcaT (YfhS) (Díaz et al. 1998).


HcaT (YfhS) of E. coli


MFS permease of 406 aas and 12 TMSs.

MFS porter of Methylobacterium nodulans


Putative metabolite transporter of 393 aas and 12 TMSs.

Porter of Sulfurimonas denitrificans (Thiomicrospira denitrificans


2.A.1.28 The Feline Leukemia Virus Subgroup C Receptor (FLVCR)/Heme Importer Family


TC#NameOrganismal TypeExample

Cell surface receptor (C-receptor) for anemia-inducing feline leukemia virus subgroup C (FLCVR, Slc49A1 or Mfsd7d) of 555 aas and 12 TMSs. It may function in choline transport (Kenny et al. 2023) or haem export in haemopoietic cells (Latunde-Dada et al., 2006Khan and Quigley, 2011) and may cause Diamond-Blackfan anemia when defective (Keel et al., 2008). Mutations of FLVCR1 in posterior column ataxia and retinitis pigmentosa result in the loss of heme export activity (Yanatori et al., 2012). Heme accumulation causes toxicity (Khan and Quigley 2018).  FLVCR1 is co-induced upon iron insufficiency in the placenta with the LDL receptor-related protein 1 (LRP1) heme receptor, and these two proteins may be important for neonatal iron status (Cao et al. 2014).  FLVCR1 is required for erythroid and αβ-, CD4 and CD8 T- cell development (Philip et al. 2015). A splice-site variant of FLVCR1 produces retinitis pigmentosa without posterior column ataxia (Yusuf et al. 2018). Protocols suitable for purification of FLVCR1a, antibody generation and structural characterization of the transporter have been reported (Chiabrando et al. 2020). FLVCR1-related disease is a rare cause of retinitis pigmentosa and hereditary sensory autonomic neuropathy (Grudzinska Pechhacker et al. 2020). More recently, integrative genetic analyses identified FLVCR1 as a plasma-membrane choline transporter in mammals (Kenny et al. 2023).


C-receptor of Homo sapiens


The MFS-Domain7 protein of 516 aas and 12 TMSs. The MFS-D7 mRNA is expressed in many human tissues, especially in lungs and testis, but its transport substrate is not known (Khan and Quigley 2018).


MFSD7 of Mus musculus


Unknown major facilitator of 407 aas and 12 TMSs.


UMF of Coriobacterium glomerans (F2NBU7)


The Fowler syndrome-associated protein, feline leukemia virus subgroup C receptor-related protein 2, FLVCR2, or SLC49A2, is probably a heme importer (Duffy et al., 2010). Mutations of SLC49A2  are observed in Fowler syndrome, a rare proliferative vascular disorder of the brain (Khan and Quigley 2018).


FLVCR2 of Homo sapiens (Q9UPI3)


MFS porter of 401 aas and 12 TMSs.


MFS porter of Leptospira biflexa (B0SL69)


Electrogenic DIRC2 (Disrupted in renal carcinoma 2) or SLC49A4.  It is glycosylated and proteolytically processed (Savalas et al., 2011)) and is targeted to lysosomes via an N-terminal dileueine motif. It is implicated in hereditary renal carcinomas (Khan and Quigley 2018). DIRC2 is an electrogenic lysosomal metabolite transporter which is subjected to and presumably modulated by limited proteolytic processing (Savalas et al. 2011).


DIRC2 of Homo sapiens (Q96SL1)

2.A.1.28.7Feline leukemia virus subgroup C receptor-related protein 1


FLVCR1 of Felis catus

MFSD7, FLVCR2 or SLC49A3 of 560 aas and 12 TMSs. It is the feline leukemia virus subgroup C receptor-2 (FLVCR2), a member of the SLC49 family of four paralogous genes in humans (Khan and Quigley 2018). It is a cell surface heme transporter, essential for erythropoiesis and systemic iron homeostasis. Mutations of SLC49A2, encoding FLVCR1, are noted in patients with Fowler syndrome (Khan and Quigley 2018). FLVCR2 is 30% identical to FLVCR1 (TC# 2.A.1.28.1).

FLCR2 of Homo sapiens


2.A.1.29 The Potential Heme Import (HemeI) Family


TC#NameOrganismal TypeExample
2.A.1.29.1Archaeal open reading frame ArchaeaOrf of Archaeoglobus fulgidus
2.A.1.29.2Archaeal open reading frame ArchaeaOrf of Aeropyrum pernix

Bacterial unknown major facilitator


UMF3 member of Frankia sp. Eul1c (E3J3E7)


2.A.1.3 The Drug:H+ Antiporter-2 (14 Spanner) (DHA2) Family


TC#NameOrganismal TypeExample

The main boron exporter in yeast, Atr1 (Kaya et al. 2009) (Aminotriazole, 4-nitroquinoline-N-oxide, etc.):H+ antiporter. Also exports L-cysteine (Yamada et al., 2006).


Atr1 of Saccharomyces cerevisiae

2.A.1.3.10Methylenomycin:H+ antiporterGram-positive bacteriaMmrB of Bacillus subtilis
2.A.1.3.11Puromycin:H+ antiporterGram-positive bacteriaPur8 of Streptomyces lipmanii
2.A.1.3.12Tetracenomycin:H+ antiporterGram-positive bacteriaTcmA of Streptomyces glaucescens
2.A.1.3.13Unconjugated bile acid uptake transporterBacteriaBaiG of Eubacterium sp. strain VPI 12708

Methylviologen (paraquat):H+ antiporter, SmvA (also exports ethidium bromide, acriflavin, malachite green, pyronine B and benzyl viologen) (Villagra et al. 2008).


SmvA of Salmonella typhimurium

2.A.1.3.15Rifamycin:H+ antiporterBacteriaRifP of Amycolatopsis mediterranei

The Me2+·tetracycline:2H+ antiporter
(Me2+ = Co2+, Mg2+, Mn2+) (also probably
a Na+ or K+:2H+ antiporter) (Wang et al. 2000).


TetA(L) of Bacillus subtilis

2.A.1.3.17The trimethoprim-sensitivity protein, YebQ (increases sensitivity to trimethoprim)BacteriaYebQ of E. coli

Efflux pump for plant-bacterial signaling molecules, phytoalexins, flavonoids and salicylate as well as drugs, RmrB


RmrB of Rhizobium etli


Paraquat efflux pump, PqrB (Cho et al., 2003)


PqrB of Streptomyces coelicolor (AAG45950)


Exporter of CCCP, nalidixic acid, rhodamine 6G, methylviologen, deoxycholate, growth inhibitory steroid hormones (estradiol and progesterone) (Elkins and Mullis, 2006) SDS, organomercurials, etc. (Nishino and Yamaguchi 2001).

Gram-negative bacteria

EmrB of E. coli (P0AEJ0)

2.A.1.3.20Long chain fatty acid efflux pump, FarB (Lee et al., 2003) (exports antimicrobial long chain fatty acids; functions with MFP auxillary protein, FarA (TC# 8.A.1.1.2)) (Lee et al., 2006)BacteriaFarB of Neisseria gonorrhoeae (AAD54074)
2.A.1.3.21Siderophore, achromobactin efflux pump, YhcA (Franza et al., 2005)BacteriaYhcA of Erwinia (Pectobacterium) chrysanthemi (AAL14569)

The Tet38 tetracycline-resistance protein of 450 aas and 14  TMSs of S. aureus (Truong-Bolduc et al., 2005). Tet38 has distinct functions, including drug efflux and host cell attachment and internalization mediated by interaction with host cell CD36. Truong-Bolduc et al. 2021 identified key amino acids involved in different functions. Cysteine substitutions of arginine 106, situated at the junction of TMS 4 and external loop L2, and glycine 151 of motif C on TMS 5, resulted in 8- to 16-fold reductions in Tet38-mediated resistance to tetracycline, with minimal effect on A549 host cell internalization. In contrast, two three-amino-acid deletions, F411P412G413, in external loop L7, situated between TMSs 13 and 14, and D38D39L40, in external loop L1, situated between TMS 1 and 2, led to decreased tetracycline resistance, but only the former affected S. aureus internalization and impaired binding to CD36 (Truong-Bolduc et al. 2021).


Tet38 of Staphylococcus aureus (AAV80464)

2.A.1.3.23The NorB multidrug resistance pump (exports hydrophilic quinolones, ethidium bromide, cetrimide, sparfloxacin, moxifloxacin and tetracycline) (Truong-Bolduc et al., 2005)BacteriaNorB of Staphylococcus aureus (BAB42529)

The VceAB multidrug (hydrophobic compounds including deoxycholate (DOC), antibiotics, such as chloramphenicol and nalidixic acid, and the proton motive force uncoupler, cyanide carbonyl m-chlorophenylhydrazone (CCCP)) resistance pump (functions with outer membrane VceC (TC#1.B.17.3.6) or OprM (2.A.6.2.21), an OMF family member; The C-terminal domain of the Pseudomonas aeruginosa OprM and the alpha-helical hairpin domain of Vibrio cholerae VceA play important roles in recognition/specificity/recruitment in the assembly of a functional, VceAB-OprM chimeric efflux pump (Bai et al., 2010).


VceAB of Vibrio cholerae
VceB (MFS), NP_231054
VceA (MFP), NP_231053


Actinorhodin (blue pigmented antibiiotic) transporter, ActII-2


ActII-2, Actinorhodin transporter of Streptomyces coelicolor (P46105).


Novobiocin/deoxycholate exporting MDR efflux pump, MdtD or YegB (Baranova and Nikaido, 2002).  Also exports arabinose but not xylose (Koita and Rao 2012). Regulated by the transcription factor, BaeR (Nagakubo et al. 2002).


YegB of E. coli (P36554)


The vacuolar basic amino acid (Arg, Lys, His) transporter, Vba3 (Shimazu et al., 2005)


Vba3 of Saccharomyces cerevisiae (P25594)

2.A.1.3.28MDR multidrug efflux pump, EbrE (involved in colony growth, dependent on Ca2+, Mg2+, Na+ and K+) (Lee et al., 2007)BacteriaEbrE of Streptomyces lividans (Q939A4)
2.A.1.3.29The metal:tetracycline/oxytetracycline resistance efflux pump, TctB (563 aas)BacteriaTctB of Streptomyces rimosus (O69070)

(Acriflavin, ethidium bromide, fluoroquinolones, etc.):H+ antiporter (Li et al. 2004; Rodrigues et al. 2011).

Gram-positive bacteria

LfrA of Mycobacterium smegmatis

2.A.1.3.30Lincomycin resistance protein; Lincomycin:H+ antiporter, LmrBBacteriaLmrB of Bacillus subtilis (O35018)

The hydrophilic fluoroquinolones efflux pump, QepA (Perichon et al., 2008). Exports hydrophilic quinolones, norfloxacin, and ciprofloxacin.


QepA of E. coli (A5H8A5)

2.A.1.3.32Landomycin A efflux pump, LanJ (Otash et al., 2008)BacteriaLanJ of Streptomyces cyanogenus (Q9ZGB6)
2.A.1.3.33Multidrug (including novobiocin, streptomycin, and actinomycin D) resistance porter, MdtP (YusP)


MdtP of Bacillus subtilis (O32182)


The P55 (MFS55) triglyceride (TAG)/drug efflux pump (Rv141Oc) (extrudes drugs including rifampicin and clifazimine, first- and second-line anti-tuberculosis drugs.) CCCP and valinomycin inhibited drug resistance (Ramón-García et al., 2009).  P55 also exports malachite green, ethidium bromide, isoniazid and ethambutol (Bianco et al. 2011).  It functions together with the outer membrane lipoprotein porin, LprG (P9WK45; TC# 9.B.138.1.1), also called P27 and Lpp-27 (Bianco et al. 2011; Farrow and Rubin 2008).  MFS55 is required together with LprG for normal colony morphology and sliding motility, possibly due to alterred cell wall composition (Farrow and Rubin 2008). MFS transporter Rv1410 and the periplasmic lipoprotein, LprG, transport triacylglycerides (TAGs) that seal the mycomembrane. Remm et al. 2023 reported a 2.7 Å structure of a mycobacterial Rv1410 homologue, which adopts an outward-facing conformation and exhibits unusual transmembrane helix 11 and 12 extensions that protrude ~20 Å into the periplasm. A small, very hydrophobic cavity suitable for lipid transport is constricted by a functionally important ion-lock likely involved in proton coupling. Combining mutational analyses and MD simulations, the authors proposed that TAGs are extracted from the core of the inner membrane into the central cavity via lateral clefts present in the inward-facing conformation. The functional role of the periplasmic helix extensions is to channel the extracted TAG into the lipid binding pocket of LprG (Remm et al. 2023).


P55 drug efflux pump of Mycobacterium tuberculosis (P71678)


EmrKY-TolC MDR efflux pump (Nishino and Yamaguchi 2001). (also exports cysteine (Yamada et al., 2006)) (similar to 2.A.1.3.2)


EmrKY-TolC of E. coli
EmrK (MFP) (C5W790)
EmrY (MFS) (C5W789)


The uridine/deoxyuridine/5-fluorouridine uptake transporter, UriP (llmg_0856) (480aas; 14TMSs) (Martinussen et al., 2010)


UriP of Lactococcus lactis (A2RJJ9)


MFS porter of unknown function


MFS porter of Streptomyces viridochromogenes (D9X7X8)


The antimicrobial efflux pump, LmrS. Exports linezolid and tetraphenylphosphonium chloride (TPCL) > sodium dodecyl sulfate (SDS), trimethoprim, and chloramphenicol. (most similar to LmrB (2.A.1.3.30)) (Floyd et al., 2010).


LmrS of Staphylococcus aureus (Q5HE38)


(Mono- and divalent organocation):H+ antiporter. Transmembrane helix 12 of QacA lines the bivalent cationic drug binding pocket (Hassan et al., 2007). Two sites, D34 and D411 are involved in substrate recognition, while E407 facilitates substrate efflux as a protonation site and plays a role as a substrate recognition site for the transport of dequalinium, a divalent quaternary ammonium compound (Majumder et al. 2019). TMS 12 and its external flanking loop are required for the structural and functional integrity of QacA, and they contain amino acids directly involved in their interactions with substrates (Dashtbani-Roozbehani et al. 2023). Cryo-EM structures of QacA from S. aureus revealed a novel extracellular loop with an allosteric role (Majumder et al. 2023). 

Gram-positive bacteria

QacA of Staphylococcus aureus (P0A0J9)


The phenazine resistance pump. It also exports D-alanyl-griseoluteic acid; possibly in conjunction with a chaperone protein, EhpR. The crystal structure of EhpR is known (Yu et al., 2011). Note: Phenazines are toxic redox active secondary metabolites that many bacteria secrete. It may be  involved in the export of griseoluteic acid, an intermediate in the biosynthesis of the broad-spectrum phenazine antibiotic, D-alanylgriseoluteic acid (Dagher et al. 2021).


EhpJ of Panloea (Enterobacter) agglomerans (O32600)


MFS efflux pump, AmvA (AedF). Mediates drug, dye, detergent, antibiotic and disinfectant resistance (Rajamohan et al., 2010; Hassan et al. 2011). 98.6% identical to AdeF (2.A.1.3.46).


AmvA of Acinetobacter baumannii (C4PAW9)


MDR pump, AdeF (AmvA) exports ethidium, DAPI, and chlorhexidine (Hassan et al. 2011). 98.6% identical to AmvA (2.A.1.3.45).


AdeF of Acinetobacter baumannii (A3M6E0)


The phenicol (florfenicol/chloramphenicol) exporter, FexB (Liu et al., 2012)


FexB of Enterococcus faecium (G9FS16)


The trichothecene efflux pump, TRI12 (Alexander et al., 1999; Wuchiyama et al., 2000). Trichothecenes are plant growth promoters and bio-control agents (See also Fang et al. (2012)). TRI12 secretes toxic trichothecene compounds like T-2 toxin, nivalenol and deoxynivalenol.


TRI12 of Fusarium sporotrichioides (Q9C1B3)


Multidrug-efflux transporter Rv1634/MT1670 of 471 aas and 14 TMSs.  Both Rv1634 and Rv1258c are believed to play a major role in drug resistance by altering the protein pump that is required to remove the active drug compounds from the bacterial cell (Panja et al. 2019). Ciprofloxacin and norfloxacin are substrates, to which M. tuberculosis strains have become resistant. The expulsion of the drugs to the outside the bacterial cell occurs through the alternating-access mechanism of N and C-terminal domains (Singh and Akhter 2021).


Rv1634 of Mycobacterium tuberculosis


Multidrug resistance protein Stp (Spectinomycin tetracycline efflux pump)


Stp of Myconbacterium tuberculosis

2.A.1.3.5(Pristinamycin I and II, rifamycin, etc.):H+ antiporterGram-positive bacteriaPtr of Streptomyces pristinaespiralis

Multidrug resistance protein 3 (Multidrug-efflux transporter 3) or Brm3, of 512 aas and 14 TMSs. Resistance to puromycin, tosofloxacin, norfloxacin, acriflavin, ethidium, and tetraphenyl phosphonium, but not ofloxacin, nalidixic acid or carbonyl cyanide m-chlorophenylhydrazone (Ohki and Murata 1997). A spontaneous B. subtilis mutant isolated in the presence of a high concentration of puromycin acquired a multidrug-resistant phenotype due to high level expression of the bmr3 gene (Ohki and Tateno 2004), and selection for improved synthesis of menaquinone-7 also caused increased expression (Cui et al. 2020).


Bmr3 of Bacillus subtilis

2.A.1.3.51Probable transport protein HsrA (High-copy suppressor of RspA)Bacteria

HsrA of Escherichia coli


Drug resistance protein YOR378W.  Does not export boron (Bozdag et al. 2011).


YOR378W of Saccharomyces cerevisiae

2.A.1.3.53Azole resistance protein 1FungiAZR1 of Saccharomyces cerevisiae
2.A.1.3.54Protein SGE1 (10-N-nonyl acridine orange resistance protein) (Crystal violet resistance protein)FungiSGE1 of Saccharomyces cerevisiae

Uncharacterized MFS-type transporter YubD


YubD of Bacillus subtilis


Putative MFS drug exporter of 461 aas and 14 TMSs.

Porter of Paenibacillus polymyxa


Uncharacterized MFS-type transporter YwoD


YwoD of Bacillus subtilis


Uncharacterized MFS-type transporter YfiU


YfiU of Bacillus subtilis


MDR efflux pump, NorC (Truong-Bolduc et al. 2006). Proposed to be a quinolone resistance exporter, NorB (Marklevitz and Harris 2016). The 3-d x-ray structure at 3.6 Å resolution has been solved in an outward open configuration (Kumar et al. 2021). The structure shows that NorC specifically interacts with an organic cation, tetraphenylphosphonium. Multidrug-resistance in S. aureus is inhibited by the endocannabinoid, anandamide (Sionov et al. 2022).


NorC (NorB) of Staphylococcus aureus

2.A.1.3.6Me2+·tetracycline:2H+ or 2K+ antiporter
(the optimal Me2+ = Co2+) (Also transports Na+ or K+out in exchange for 2H+.)
BacteriaTetK of Staphylococcus aureus (P02983)

MDR efflux pump, SdrM.  Exports norfloxacin, acriflavin and ethidium bromide (Yamada et al. 2006). Multidrug-resistance in S. aureus is inhibited by the endocannabinoid, anandamide (Sionov et al. 2022).


SdrM of Staphylococcus aureus


MDR efflux pump, MdeA.  Exports quaternary ammonium compounds and antibiotics (Huang et al. 2004). Also exports hoechst 33342, doxorubicin, daunorubicin, tetraphenyl phosphonium, ethidium bromide and rhodamine 6G (Yamada et al. 2006). Multidrug-resistance in S. aureus is inhibited by the endocannabinoid, anandamide (Sionov et al. 2022).


MdeA of Staphylococcus aureus


MDR efflux pump, AedC (Hassan et al. 2011).  Shown to export chloramphenicol and tetracycline.


AedC of Acinetobacter baumannii


Iron homeostasis protein, AedD; may function in siderophore export (Hassan et al. 2011).


AedD of Acinetobacter baumannii


Uptake permease for cholate (steroid) metabolites, CamM of 513 aas and 14 TMSs.  Uptake of 3,7(R),12(S)-trihydroxy-9-oxo-9,10-seco-23,24-bisnorchola-1,3,5(10)-trien-22-oate was observed (Swain et al. 2012).


CamM of Rhodococcus jostii


ThMFS1 of 563 aas and 14 TMSs.  Catalyzes export of fungicides causing tolerance.  It exports trichodermin, but it is not the only exporter of this secondary metabolite (Liu et al. 2012). Trichothecenes are the sesquiterpenes secreted by Trichoderma spp. residing in the rhizosphere. These compounds have been reported to act as plant growth promoters and bio-control agents (Chaudhary et al. 2016).


MFS1 of Trichoderma harzianum (Hypocrea lixii)


MFS permease of 413 aas and 12 TMSs. Encoded within the SoxR regulon; possibly a drug exporter (Naseer et al. 2014).


MFS permease of Pseudomonas aeruginosa


MFS porter of 462 aas and 14 TMSs


MFS porter of Deinococcus radiodurans


The PfMFS transporter (551 aas; 14 putative TMSs) is involved in the acid resistance and intracellular pH homeostasis of Penicillium funiculosum (Xu et al. 2014). This protein (AIJ02309) was not in UniProt when enterred into TCDB, and its closest orthologue, PmMFS of Penicillium marneffei, is therefore presented here. These two proteins are 82% identical.


PfMFS of Talaromyces (Penicillium) funiculosum


Drug resistance pump, YMR279c of 540 aas.  When overexpressed, confers boron resistance, but is not induced by boron (Bozdag et al. 2011). 

YMR279c of Saccharomyces cerevisiae (Baker's yeast)

2.A.1.3.7Actinorhodin:H+ antiporter, ActVa or ActA (Tahlan et al., 2007)Gram-positive bacteriaActVa of Streptomyces coelicolor

Probable exporter of aromatic compounds of 559 aas and 16 putative TMSs in an apparent 4 + 4 + 4 + 4 arrangement. May function in aromatic compoound detoxification.  Regulated by a MarR-like transcriptional regulator that is encoded in the same operon. A ten-fold induction occurs in response to aromatic aldehydes such as benzaldehyde (Fiorentino et al. 2007). The same MarR protein controls transcription of a gene encoding an NADH-dependent alcohol dehydrogenase (Sso2536).

Sso1351 of Sulfolobus solfataricus


Putative multidrug-resistance exporter of 553 aas and 14 putative TMSs, KNQ1. It is a drug efflux permease for several toxic compounds that in multiple copies confer increased dithiothreitol resistance. KNQ1 does not export dithiothreitol or function in recombinant protein secretion. KNQ1 gene amplification or deletion resulted in enhanced transcription of iron transport genes, suggesting,  a role in iron homeostasis on which dithiothreitol tolerance may depend (Marchi et al. 2007).

KNQ1 of Kluyveromyces lactis (Yeast) (Candida sphaerica)


Riboflavin transporter of 456 aas and 14 TMSs, RibZ (Gutiérrez-Preciado et al. 2015).

RibZ of Peptoclostridium difficile (Clostridium difficile)


Multidrug resistance Mfs1 protein of 583 aas and 14 TMSs.  Exports natural mycotoxins and a variety of fungicides in Mycosphaerella graminicola (Roohparvar et al. 2007). Etridiazole (EDZ) is a thiadiazole-containing fungicide commonly used to control Pythium and Phytophthora spp. Studies have shown that EDZ is teratogenic. A zebrafish (Danio rerio; ZF) model has been used to explore the molecular pathways associated with EDZ toxicity, and itwas concluded that there are several (Vasamsetti et al. 2023).

MDR exporter, Mfs1 of Zymoseptoria tritici (Speckled leaf blotch fungus) (Septoria tritici)


Polyamine/cationinc amino acid exporter, CmgA.  Exports L-lysine, L-arginine, L-citrulline, the diamine/polyamine, putrescine, cadaverine, and possibly spermdine and spermine (Nguyen et al. 2015 ;Lubitz et al. 2016).

CmgA of Corynebacterium glutamicum


Erythromycin/macrolide export system of 499 aas and 14 TMSs, ErmB (Zhou et al. 2014). 

ErmB of Streptococcus pyogenes


MFS transporter of 530 aas and 14 TMSs, SgvT1.  Exports griseoviridin and viridogrisein (etamycin) (Xie et al. 2017).

SgvT1 of Streptomyces griseoviridis


Drug resistance efflux porter, SgvT3 of 464 aas and 14 TMSs. (Xie et al. 2017).

SgvT3 of Streptomyces griseoviridis


Drug resistance pump, EfpA of 530 aas and 14 TMSs.  May function with IniABC (see TC# 9.B.282), shown to influence resistance to several drugs (Colangeli et al. 2007).  Structures of the essential drug efflux pump EfpA from Mycobacterium tuberculosis reveal the mechanisms of substrate transport and small-molecule inhibition (Wang et al. 2024).

EfpA of Mycobacterium tuberculosis


Multidrug resistance MFS exporter, MFS54 of 538 aas and 14 TMSs. A fungal mutant lacking AaMFS54 produced fewer conidia and showed increased sensitivity to many potent oxidants (potassium superoxide and singlet-oxygen generating compounds) as well as  xenobiotics (2,3,5-triiodobenzoic acid and 2-chloro-5-hydroxypyridine), and fungicides (clotrimazole, fludioxonil, vinclozolin, and iprodione) (Lin et al. 2018). Virulence assays on citrus leaves inoculated by spraying with spores revealed that AaMFS54 mutant induced less severe lesions than wild-type.

MFS54 of Alternaria alternata

2.A.1.3.8Cephamycin:H+ antiporterGram-positive bacteriaCmcT of Nocardia lactamdurans

Uncharacterized EmrB/QacA-like durg resistance transporter of 540 aas and 14 TMSs. The gene encoding this protein is adjacent to a 3 component putative ABC drug exporter of TC# 3.A.1.122.32.

U-MFS porter of Cellulomonas flavigena


multidrug (tetracycline, kanamycin, rhodamin 6G, ampicillin, acriflavine, ethidium bromide, and tetraphenylphosphonium chloride) resistance exporter, MdeA, of 453 aas and 14 TMSs (Kim et al. 2013).

MdeA of Streptococcus mutans


Multidrug resistance transporter protein of 519 aas and 14 TMSs. It exports 2-thiocyanatopyridine derivatives (Nunvar et al. 2019).

MDR pump of Burkholderia cenocepacia (Burkholderia cepacia)


AflT efflux pump of 514 aas and 14 TMSs (Yu et al. 2004).  Its gene is part of the gene cluster that mediates the biosynthesis of aflatoxins (Yu et al. 2004).

AflT of Aspergillus parasiticus


Trichothecene efflux pump, Tri12, of 590 aas and 14 TMSs (Lee et al. 2002). It may function as a phospholipid flippase, and five flippases (FgDnfA, B, C1, C2 and D have been identified  (Yun et al. 2020). FgDnfA is critical for normal vegetative growth while the other flippases are dispensable. FgDnfA and FgDnfD are crucial for fungal pathogenesis, and a remarkable reduction in deoxynivalenol (DON) production was observed in DeltaFgDNFA and DeltaFgDNFD strains. Deletion of the FgDNFB gene increased DON production to about 30 fold. FgDnfA and FgDnfD play positive roles in the regulation of trichothecene (TRI) gene (TRI1, TRI4, TRI5, TRI6, TRI12, and TRI101) expression and toxisome reorganization, while FgDnfB acts as a negative regulator of DON synthesis. FgDnfB and FgDnfD have redundant functions in the regulation of phosphatidylcholine transport, and double deletion of FgDNFB and FgDnfD showed defects in fungal development, DON synthesis, and virulence. Thus, the distinct and specific functions of flippase family members in F. graminearum have been determined, and FgDnfA, FgDnfD, and FgDnfB have specific spatiotemporal roles during toxisome biogenesis (Yun et al. 2020). This protein is 76% identical to the protein with TC# 2.A.1.3.47, and they probably catalyze the same reaction(s).

Tri12 of Gibberella zeae (Wheat head blight fungus) (Fusarium graminearum)


Acinetobacter baumannii ATCC17978 MDR pump (A1S_0188) of the DHA2 family in the MFS (Hassan et al. 2011). It is of 463 aas with 14 TMSs. There are 6 DHA2 members in A. baumannii. One of these, called AadT, exports a variety of drugs (Naidu et al. 2023).

MDR pump AedA of Acinetobacter baumannii


Antimony, SbIII and SbV, resistance MFS efflux protein of xxx aas and 14 TMSs in a 6 + 2 + 6 TMS arrangement with both 6 TMS domains having a 2 + 2 + 2 TMS arrangement (Yang et al. 2024). AntB is encoded on the chromosome of the arsenite-oxidizing bacterium Ensifer adhaerens E-60 that confers resistance to Sb(III) and Sb(V). The antB gene is adjacent to a gene encoding a LysR family transcriptional regulator termed LysRars, which is an As(III)/Sb(III)-responsive transcriptional repressor that is predicted to control expression of antB. Similar antB and lysRars genes are found in related arsenic-resistant bacteria, especially strains of Ensifer adhaerens, and the lysRars gene adjacent to antB encodes a member of a divergent subgroup of putative LysR-type regulators. Closely related AntB and LysRars orthologs contain three conserved cysteine residues, which are Cys17, Cys99, and Cys350 in AntB and Cys81, Cys289 and Cys294 in LysRars, respectively. Expression of antB is induced by As(III), Sb(III), Sb(V) and Rox(III) (4-hydroxy-3-nitrophenyl arsenite). Heterologous expression of antB in E. coli AW3110 (Δars) conferred resistance to Sb(III) and Sb(V) and reduced the intracellular concentration of Sb(III) (Yang et al. 2024). 

AntB of Ensifer adhaerens

2.A.1.3.9Lincomycin:H+ antiporterGram-positive bacteriaLmrA of Streptomyces lincolnensis

2.A.1.30 The Putative Abietane Diterpenoid Transporter (ADT) Family


TC#NameOrganismal TypeExample

Putative abietane uptake permease (in a gene cluster for degradation of abietane diterpenoids), DitE, of 547 aas and 12 TMSs (Martin and Mohn 2000). Abietane diterpenoids are defense compounds synthesized by trees that are abundant in natural environments and occur as significant pollutants from pulp and paper production (Smith et al. 2007).


DitE of Pseudomonas abietaniphila BKME-9


Uncharacterized MFS transporter of 410 aas and 12 TMSs.

MFS porter of Actinomadura macra


Enterobactin exporter, EntS (gene, tetv1) of 549 aas and 12 TMSs.

EntS of Stenotrophomonas maltophilia


2.A.1.31 The Nickel Resistance (Nre) Family


TC#NameOrganismal TypeExample
2.A.1.31.1The Ni2+ efflux pump, NreB (Ni2+ inductible) BacteriaNreB of Achromobacter xylosoxidans plasmid pTOM
2.A.1.31.2The Ni2+ resistance protein, NrsD BacteriaNrsD of Synechocystis PCC6803

The unknown porter, YfiS


YfiS of Bacillus subtilis (O31561)

Kurstakin/surfactin exporter of 417 aas (in B. subtilis) (Li et al. 2015).  This protein is an orthologue of the B. subtilis protein (Li et al. 2015).


KrsE of Bacillus cereus


Uncharacterized MFS porter of 455 aas

Green Algae

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Uncharacterized MFS porter (residiues 1 - 450) with hydrophilic C-terminal protein kinase domain.  The protein is of 858 aas.

Green algae

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Putative bacilysin exporter, BacE, of 484 aas and10 - 11 TM

BacE of Candidatus Heimdallarchaeota archaeon AB_125


Nickel resistance membrane nickel efflux protein NirA of 432 aas and 12 TMSs.  This protein is 99.7% identical to a trunkated homolog from Klebsiella oxytoca (Park et al. 2008).

NirA of Enterobacter cloacae


2.A.1.32 The Putative Aromatic Compound/Drug Exporter (ACDE) Family


TC#NameOrganismal TypeExample

Putative aromatic compound/drug exporter. Enhances expression of the sigma X gene that functions to modify the cell envelope (Turner and Helmann, 2000). yitG is reported to be a mutator gene that inhibits transition base substitutions (Sasaki and Kurusu, 2004).


YitG of Bacillus subtilis

2.A.1.32.2Bacillibactin exporter, YmfE (199aas; 6TMSs) (Miethke et al., 2008) (resembles the 2nd half of YitG of B. subtilis (2.A.1.32.1). The sequence provided under acc# O31763 is only a fragment of the full length gene.BacteriaYmfE of Bacillus subtilis (O31763)

Putative copper/multidrug efflux protein, YfmO.  The yfmPO operon is autoregulated by the MerR homologue, YfmP (a repressor). The copZA operon encodes CopA, a copper ATPase (TC# 3.A.3.5.18) which is induced by a copper dependent mechanism. Since a yfmP null mutant had poor copZA induction but elevated levels of the YfmO efflux pump, YfmO could catalyze copper efflux and be responsible for reduced copZA induction. Consistent with this model, a yfmP yfmO double mutant showed normal induction by copper (Gaballa et al. 2003).


YfmO of Bacillus subtilis


2.A.1.33 The Putative YqgE Transporter (YqgE) Family

These proteins are most closely related to TC#s 2.A.1.21 and 2.A.1.46, and therefore may be MDR exporters.


TC#NameOrganismal TypeExample

MFS homologue, YqgE. It is cotranscribed with ftsI, encoding the peptidoglycan transpeptidase that crosslinks peptidoglycan strands, releasing free D-alanine. Possibly YqgE is a D-alanine uptake porter. Its expression causes a decrease in the amount of sigma W synthesis, the sigma factor for genes involved in detoxification and antimicrobial synthesis (Turner and Helmann 2000).

Bacteria; Archaea

YqgE of Bacillus subtilis (P54487)


YqgE homologue


YqgE homologue of Bacteroides ovatus (A7LYG9)


YqgE homologue (encoded near an α-glucuronidase; GH31 family; divergently transcribed). Therefore could be an uptake system for glucouronides.


YqgE homologue of Sulfolobus tokodaii (Q96XI6)


Uncharacterized protein of 385 aas and 12 TMSs.

UP of Candidatus Beckwithbacteria bacterium


2.A.1.34 The Sensor Kinase-MFS Fusion (SK-MFS) Family


TC#NameOrganismal TypeExample

Sensor kinase (N-terminal 400 residues)/MFS fusion protein. The N-terminal domain resembles the sensor kinase of 414 aas of Anaeromyxobacter sp. KJ (ACG71775). The C-terminal MFS domain most resembles those of TC family 2.A.1.2 (DHA1).


Fusion protein of Bordetella pertussis (Q7VWI9)


MFS carrier with N-terminal hydrophilic domain with 3 putative TMSs of about 2880 aas. The protein is of 676 aas with 15 TMSs.

MFS permease fusion protein of Fodinicurvata fenggangensis


MFS carrier of 526 aas and an N-terminal hydrophilic domain with 1 TMS. 

MFS carrier fusion protein of Herbaspirillum huttiense


2.A.1.35 The Fosmidomycin Resistance (Fsr) Family


TC#NameOrganismal TypeExample

The fosmidomycin resistance (Fsr) protein (confers fosmidomycin, trimethoprim and carbonylcyanide m-chlorophenylhydrazone (CCCP) resistance) (Fujisaki et al. 1996).


Fsr of E. coli

2.A.1.35.2The cationic microbial peptide resistance (RosA) proteinBacteriaRosA of Yersinia enterocolitica

MFS transporter of 388 aas and 12 TMSs


MFS porter of Sulfobacillus acidophilus


2.A.1.36 The Acriflavin-sensitivity (YnfM) Family


TC#NameOrganismal TypeExample

The acriflavin-sensitivity protein, YnfM (increases sensitivity to acriflavin specifically).  Also exports arabinose but not xylose (Koita and Rao 2012).


YnfM of E. coli


Hypothetical MFS carrier of 411 aas and 12 TMSs.


MFS carrier of Serratia proteamaculans (A8GHT9)


Putative uncharacterized transporter YgaY


YgaY of Escherichia coli


MdrA.  Putative MDR transporter that may export cationic and hydrophobic compounds, Sco4007.  Regulated by a TetR-like repressor that binds drugs (Hayashi et al. 2013).


MdrA (Sco4007) of Streptomyces coelicolor


MFS carrier of 389 aas


MFS carrier of Rhizobium loti


Succinate/dicarboxylate transporter, YnfM, of 416 aas and 12 TMSs. It exports succinate under both aerobic and anaerobic conditions (Fukui et al. 2019).

YnfM of Corynebacterium glutamicum


2.A.1.37 The Uncharacterized Major Facilitator-4 (UMF4) Family

This family possibly includes drug exporters


TC#NameOrganismal TypeExample

Unknown Major Facilitator-4 family member, UMF4A, of 396 aas and 12 TMSs.


UMF4A of Brachyspira pilosicoli


UMF4 family member of 399 aas and 12 TMSs, UMF4B.


UMF4B of Brachyspira murdochii


UMF4C of 407 aas and 12 TMSs.


UMF4C of Ferroplasma sp. 


UMF4D of 399 aas and 12 TMSs


UMF4D of Sphaerochaeta pleomorpha


UMF4E of 373 aas and 12 TMSs


UMF4E of Caldisphaera lagunensis


2.A.1.38 The Enterobactin (Siderophore) Exporter (EntS) Family


TC#NameOrganismal TypeExample

The enterobactin (siderophore) exporter, EntS or YbdA (Bleuel et al., 2005).  May also export arabinose but not xylose (Koita and Rao 2012).


EntS (YbdA) of E. coli

2.A.1.38.2The putative siderophore exporter (DUF 894; Pfam 05977), VabSBacteriaVabS of Listonella anguillarum (Q0E7C5)
2.A.1.38.3Enterobactin exporter, EntS (Crouch et al., 2008) (probably orthologous to 2.A.1.38.1). BacteriaEntS of Salmonella typhimurium

Uncharacterized MFS protein of 429 aas and 12 TMSs.

UP of Lactobacillus rhamnosus


2.A.1.39 The Vibrioferrin (Siderophore) Exporter (PrsC) Family


TC#NameOrganismal TypeExample

The vibrioferrin (siderophore) exporter, PrsC (Tanabe et al., 2003; Tanabe et al., 2006)


PrsC of Vibrio parahaemolyticus (BAC16546)


MFS permease of 398 aas and 12 TMSs.

MFS permease of Xanthomonas campestris


Putative efflux pump of 383 aas and 12 TMSs.

Efflux pump of Kitasatospora setae (Streptomyces setae)


2.A.1.4 The Organophosphate:Pi Antiporter (OPA) Family


TC#NameOrganismal TypeExample
2.A.1.4.1Sugar-P:Pi antiporter (transports many sugar-phosphates - both 1- and 6-P esters)BacteriaUhpT of E. coli (P0AGC0)

2-phosphonoacetate/2-phosponopropionate uptake porter of 428 aas, PhnB.  The PhnA protein is a hydrolase, and PhnC is a positive transcriptional regulator.  Induction occurs with either of the two substrates (Kulakova et al. 2001).


PhnB of Pseudomonas fluorescens


Glycerol-3-phosphate:inorganic phosphate antiporter, GlpT (Frohlich and Audia 2013).


GlpT of Rickettsia prowazekii


P-glycerate:Pi antiporter, Pgt.  Takes up phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate as sole sources of carbon and energy for rapid growth (Saier et al. 1975).  Not present in E. coli K12, but is present in many intracellular pathogenic strains of E. coli (Tang and Saier, unpublished observations).


PgtP of Salmonella typhimurium


Glycerol-P:Pi antiporter (may function by a 'rocker switch' mechanism; Law et al., 2007). The 3-d structure is known (3.3Å resolution) (Huang et al., 2003; Lemieux et al., 2005; Lemieux, 2007).


GlpT of E. coli

2.A.1.4.4Hexose-P:Pi antiporter regulatory protein; senses external glucose-6-P and transports it with high affinity and low efficiencyBacteriaUhpC of E. coli

Microsomal (ER/Golgi) glucose-6-P:Pi antiporter (glycogen storage disease (GSD1b and 1c); Gierke''s disease protein) (SLC37A2 in mice, associated with white adipose tissue obesity and expressed at high levels in macrophage) (4 isoforms present in humans (Chen et al., 2008)).  SLC37A1 and A2 can not substitute for A4.  91 mutations have been observed in human patients (Chou and Mansfield 2014).  Inhibited by cholorogenic acid although SLC37A1 and A2 are not.  SLC37A3 had not been characterized by 2014 (Chou and Mansfield 2014).


SLC37A4 of Homo sapiens

2.A.1.4.6Glucose-6-P:Pi antiporter, Hpt (may also transport other organophosphates including C3 organophosphates).BacteriaHpt of Chlamydia pneumoniae (spQ9Z7N9 & gi9979188) & pirA72050

Putative glycerol-3-phosphate (G-3-P) transporter, G3PP (most similar to TC# 2.A.1.4.6, 22% identity).  Has been shown to catalyze glucose 6-P:Pi antiport across the endoplasmic reticular membrane(Pan et al. 2011).


SLC37A1 of Homo sapiens


solute carrier family 37 (putative glycerol-3-phosphate transporter), member 2.  Has been shown to catalyze glucose 6-P:Pi antiport across the endoplasmic reticular membrane (Pan et al. 2011). N-glycosylation is critical for the function of bovine PepT2 (Wang et al. 2020).


SLC37A2 of Homo sapiens

2.A.1.4.9 solute carrier family 37 (glycerol-3-phosphate transporter), member 3AnimalsSLC37A3 of Homo sapiens

2.A.1.40 The Major Facilitator Superfamily Domain-containing Protein (MFS-DP) Family


TC#NameOrganismal TypeExample

Major facilitator superfamily domain-containing protein 5, MfsD5 or SLC61A1) of 481 aas and 13 TMSs in a 7 + 6 TMS arrangement. 


MfsD5 of Danio rerio


Major facilitator superfamily domain-containing protein 5, MFSD5 or SLC61A1, of 450 aas and 13 TMSs in a 5 + 2 + 6 TMS arrangement. It mediates high-affinity (550 nM Km) intracellular uptake of the rare oligo-element molybdenum.  It is probably a molybdate (the oxianion molybdate)/anion uptake porter (Tejada-Jiménez et al. 2011). In mammals, it is expressed in the brain and may play a role in energy homeostasis (Perland et al. 2016).



Molybdate uptake porter of Homo sapiens

2.A.1.40.3Major facilitator superfamily domain-containing protein 5Animalsmfsd5 of Xenopus tropicalis

2.A.1.41 The Putative Bacteriochlorophyll Delivery (BCD) Family


TC#NameOrganismal TypeExample
2.A.1.41.1Putative pigment transporter (Young and Beatty, 1998)Photosynthetic bacteriaLhaA of Rhodobacter capsulatus
2.A.1.41.2Putative pigment transporter (Young and Beatty, 1998)Photosynthetic bacteriaPucC of Rhodobacter capsulatus
2.A.1.41.3Putative bacteriochlorophyll synthasePhotosynthetic bacteriaBch2 of Rhodobacter capsulatus

2.A.1.42 The Lysophospholipid Transporter (LplT) Family


TC#NameOrganismal TypeExample

The lysophospholipid (LPL) transporter, LplT (Harvat et al., 2005).  Substrates include lyso-PE, lyso-cardiolipin, diacylcardiolipin, fully-deacylated cardiolipin and lyso-phosphatidylglycerol, but not lysophosphatidylcholine, lysophosphatidic acid or phosphatidic acid (Lin et al. 2016). Reacylation by acyltransferase/acyl-acyl carrier protein synthetase then occurs on the inner leaflet of the membrane.Thus, a fatty acid chain is not required for LplT transport. A "sideways sliding" mechanism was proposed to explain how a conserved membrane-embedded α-helical interface excludes diacylphospholipids from the LplT binding site to facilitate efficient flipping of lysophospho-lipids across the cell membrane (Lin et al. 2016). Thus, a fatty acid chain is not required for LplT transport. Fruther, LplT cannot transport lysophosphatidic acid, and its substrate binding was not inhibited by either orthophosphate or glycerol 3-phosphate, indicating that either a glycerol or ethanolamine headgroup is the chemical determinant for substrate recognition. Diacyl forms of PE, phosphatidylglycerol, or the tetra-acylated form of cardiolipin could not serve as competitive inhibitors .A "sideways sliding" mechanism was proposed to explain how a conserved membrane-embedded α-helical interface can exclude diacylphospholipids from the LplT binding site. A dual substrate-accessing mechanism, in which LplT recruits LPLs to its substrate-binding site via two routes, either from its extracellular entry site, or through a membrane-embedded groove between transmembrane helices, and it then moves them towards the inner membrane leaflet (Lin et al. 2018).


LplT of E. coli (NP_417312)


The lysophospholipid transporter-2-acyl glycerophosphoethanolamine acyl transferase/acyl ACP synthetase (LplT-Pls-ACS) fusion protein (Harvat et al., 2005). 


The fused LplT-PlsC-ACS of Bradyrhizobium japonicum (BAC47589)


2.A.1.43 The Putative Magnetosome Permease (PMP) Family


TC#NameOrganismal TypeExample
2.A.1.43.1The putative magnetosomal permease, MamH (Schubbe et al., 2003)BacteriaMamH of Magnetospirillum gryphiswaldense (Q6NE63)

The magnetosome permease fused to a C-terminal YedZ-like domain, MamZ (von Rozycki et al., 2004). This protein has 649 aas and 18 TMSs with a C-terminal YedZ domain and is therefore in the YedZ superfamily as well as the MFS. The two MFS proteins in the magnetosome membrane, MamZ and MamH (44% identical to MamZ), appear to overlap in function as deletion of their two genes have additive effects (Raschdorf et al. 2013). Magnetosome biogenesis has been reviewed ().


PMP of Magnetospirillum magneticum (Q2W8K5)


2.A.1.44 The L-Amino Acid Transporter-3 (LAT3) Family

This family is also called the SLC43 family.


TC#NameOrganismal TypeExample

The L-amino acid transporter-3, LAT3 (transports neutral amino acids such as L-leucine, L-isoleucine, L-valine, and L-phenylalanine by a Na+-independent, electroneutral, facilitated diffusion process; it also transports amino acid alcohols and thyroid hormones such as 3,3'-T2) (Prostate cancer up-regulated gene product) (Krause and Hinz 2019).


SLC43A1 of Homo sapiens


L-amino acid transporter-4 (LAT4) has the same specificity and is 57% identity to LAT3. Na+, Cl- and pH independent; not trans-stimulated; it has been reported to have two kinetic components, a low affinity component sensitive to NEM, and a high affinity component insensitive to NEM. It is found in the basolateral membrane of epithelial cells in the distal tubule and collecting duct of the kidney and the crypt cells in the intestine (Bodoy et al., 2005). It can transport throid hormones such as 3,3'-T2 (Krause and Hinz 2019).


SLC43A2 of Homo sapiens

2.A.1.44.3 solute carrier family 43, member 3AnimalsSLC43A3 of Homo sapiens

Similar to MFS transporter Fmp4; of 614 aas and 12 TMSs in a 6 + 6 TMS arrangement where the two 6 TMS units are separated by a large hydrophilic domain.

MFS porter of Leptosphaeria maculans


2.A.1.45 The 2,4-diacetylphloroglucinol (PHL) Exporter (PHL-E) Family

This family is most closely related to TC# 2.A.1.15.


TC#NameOrganismal TypeExample
2.A.1.45.1The 2,4-diacetylphloroglucinol resistance/general stress porter, PhlE (Abbas et al., 2004)BacteriaPhlE of Pseudomonas fluorescens (CAD65845)

Probable metabolite transporter of 440 aas and 12 TMSs.

Porter of Pseudomonas syringae


Putative aromatic acid uptake porter of 450 aas and 12 TMSs.

Porter of Erwinia billingiae


2.A.1.46 The Uncharacterized Major Facilitator-5 (UMF5) Family

This family includes probable MDR pumps.


TC#NameOrganismal TypeExample

Probable MDR efflux transporter of 396 aas and 12 TMSs.  The closest homolologues are MDR pumps in subfamilies 2.A.1.2 and 2.A.1.3.


Probable MDR transporter of Bordetella pertussis (Q7W0Q7)


Probable staphylopine exporter, CntE.  Staphylopine is a broad spectrum metalophore similar to plant nicotianamine that binds several divalent ions (nickel, cobalt, zinc, copper and iron) (Ghssein et al. 2016).  The uptake system for metal bound staphylpine is TC# 3.A.1.5.43).  CntE is downstream of the genes coding for the uptake system, CntABCDF (Ghssein et al. 2016).

CntE of Staphylococcus aureus


Uncharacterized MFS porter of 403 aas and 12 TMSs.

UP of Candidatus Wolfebacteria bacterium


Uncharacterized MFS permease of 406 aas and 12 TMSs.

UP of Candidatus Saccharibacteria bacterium


Membrane protein of unknown function of 406 aas and 12 TMSs

Membrane protein of unknown function of Canditatus Saccharibacteria bacterium


Putative MDR efflux transporter of 390 aas and 12 TMSs.  The closest homolologues are MDR pumps in subfamilies 2.A.1.2 and 2.A.1.3.


Putative transporter of Tropheryma whipplei (Q83N16)


Putative drug resistance UMF5 family member


Putative MDR pump of Leishmania infantum


UMF15 family member


UMF5 homologue of Methanosphaerula palustris (B8GFY3)


Putative quinolone resistance protein


MFS porter of Bacillus cereus (C2UR80)


UPF0226 protein YfcJ.  Catalyzes export of arabinose but not xylose (Koita and Rao 2012).


YfcJ of E. coli


UPF0226 protein, YhhS.  Exports arabinose but not xylose (Koita and Rao 2012).  Also may export the herbicide, glyphosate (Staub et al. 2012).


YhhS of E. coli


MFS carrier of 366 aa


MFS carrier of Sulfolobus solfataricus


Uncharacterized MFS porter of 430 aas


MFS porter of Halosimplex carlsbadense


2.A.1.47 The Uncharacterized Major Facilitator-6 (UMF6) Family

These porters may be drug exporters.


TC#NameOrganismal TypeExample
2.A.1.47.1Putative transporterBacteriaPutative transporter of Lactobacillus plantarum (NP_784357)

UMF6 family member


MFS carrier of Streptococcus suis (A4VY05)


Possible antibiotic peptide exporter (encoded in an operon together with lantibiotic biosynthesis enzymes)


UMF6 family member of Streptococcus pneumoniae (B2IRN2)


MFS permease of 408 aas


MFS permease of Streptococcus pneumoniae


2.A.1.48 The Vacuolar Basic Amino Acid Transporter (V-BAAT) Family


TC#NameOrganismal TypeExample
2.A.1.48.1The vacuolar basic amino acid (histidine, lysine and arginine) transporter, Vba1 (catalyzes uptake into the vacuoles (equivalent to efflux from the cytoplasm)) (most similar to family 2.A.1.3; DHA2; 13-14 putative TMSs) (Shimazu et al., 2005)YeastVba1 of Saccharomyces cerevisiae (NP_013806)
2.A.1.48.2The vacuolar basic amino acid (Arg, Lys, His) transporter, Vba2 (Shimazu et al., 2005)YeastVba2 of Saccharomyces cerevisiae (P38358)
2.A.1.48.3Vacuolar G0 arrest protein, Fnx1; involved in amino acid (e.g., his, lys, ile, asn, etc) uptake into the vacuole (Chardwiriyapreecha et al., 2008).YeastFnx1 of Schizosaccharomyces pombe (Q09752)
2.A.1.48.4Vacuolar amino acid uptake system, Fnx2 (Chardiwiriyapreecha et al., 2008)YeastFnx2 of Schizosaccharomyces pombe (O59726)

Originally considered to be vacuolar basic amino acid transporter 4, but it my not act on amino acids, but exports drugs such as azoles.  May also play a role in vacuolar morphology (Kawano-Kawada et al. 2015).


VBA4 of Saccharomyces cerevisiae S288c


2.A.1.49 The Endosomal Spinster (Spinster) Family


TC#NameOrganismal TypeExample

The spinster protein, spin1 or spns1 gene product (involved in synaptic growth regulation; interacts with Bcl-2/Bcl-xL, affecting programmed cell death) (Nakano et al., 2001; Sanyal and Ramaswami, 2002; Yanagisawa et al., 2003).  Probably transports sphingosine-1-phosphate (Fukuhara et al. 2012), but polymorphisms in spns1 are associated with alterred triglyceride levels (Västermark et al. 2012).


Spinster of Drosophila melanogaster (AAG43825)


MFS multidrug exporter of 429 aas and 12 TMSs.  Exports capreomycin and ethidium bromide, and deletion mutants grow faster than wild type cells (Zhang et al. 2015).


MDR pump of Mycobacterium smegmatis


Uncharacterized protein of 656 aas and 12 TMSs

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Spinster 3, SPNS3 (SLC63A3), of 512 aas and 12 TMSs.  The evolutionary conservation, predicted structure and neuronal expression have been characterized (Perland et al. 2017). It probably exports sphigosine-1- phosphate.

SPNS3 of Homo sapiens


MFS porter, MFR1, of 853 aas and 12 TMSs in an apparent 6 + 2 + 4 TMS arrangement.

MFR1 of Plasmodium falciparum


The spinster homologue, Spin1 or Spns1 (SLC63A1) of 528 aas and 12 TMSs. It interacts with Bc1-2/Bc1-XL to induce a caspase-independent autophagic cell death (Yanagisawa et al., 2003). It is a spingosine-1-phosphate (S1P) (or sphingolipid) exporter (Nijnik et al. 2012). S1P is important for lymphocyte trafficking, immune responses, vascular and embryonic development, cancer, bone homeostasis (Zhu et al. 2018). S1P is produced intracellularly and then secreted into the circulation to engage in the above physiological or pathological processes by regulating the proliferation, differentiation and survival of target cells. SPNS2 acts as a mediator of intracellular S1P release. The SPNS1-dependent lysosomal lipid transport pathway enables cell survival under choline limitation (Scharenberg et al. 2023). The orphan lysosomal transmembrane protein SPNS1 is critical for cell survival under choline limitation. SPNS1 loss leads to intralysosomal accumulation of lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE). SPNS1 is a proton gradient-dependent transporter of LPC species from the lysosome for their re-esterification into phosphatidylcholine in the cytosol (Scharenberg et al. 2023). 


Spin1 of Homo sapiens (Q9H2V7)


Probable sphingosine-1-phosphate (or sphingolipid) transporter, spinster homologue 3 (by similarity).


Spinster homologue 3 of Arabidopsis thaliana (F4IKF6)


Protein Spinster homologue 2 (Spns2 or protein two of hearts).  Exports sphingosine-1-P (S1P) and the immunomodulating agent, FTY720 (Hisano et al. 2011; Nijnik et al. 2012).  S1P is a secreted lipid mediator that functions in vascular development. In the yolk syncytial layer, Spns2 functions in S1P secretion, thereby regulating myocardial precursor migration (Kawahara et al. 2009).


Spns2 of Danio rerio


Probable sphingosine-1-phosphate or sphingolipid transporter, Spinster homologue 1 (by similarity).


At5g65687 of Arabidopsis thaliana


Sphingosine-1-phosphate/dehydrosphingosine-1-P transport protein, Spinster 2, SPNS2 of 549 aas and 12 TMSs. It is involved in immune development and lymphocyte trafficing (Nijnik et al. 2012; Fukuhara et al. 2012). The functions and the mechanisms of SPNS2 in the pathogenesis of cancer have been reviewed (Fang et al. 2020).


SPNS2 of Homo sapiens


Bacterial Spinster homologue; possible sphingosine-1-phosphate transporter (by similarity only).


Spinster homologue of Myxococcus xanthus


Bacterial spinster homologue.  Possible sphingosine-1-phosphate transporter (by similarity only).


Spinster homologue of Terriglobus saanensis


The cis, cis muconate transporter of 508 aas.

Animals (Insects)


MucK of Bombyx mori (Silk moth)


2.A.1.5 The Oligosaccharide:H+ Symporter (OHS) Family


TC#NameOrganismal TypeExample

β- and α-galactopyranoside:H+ symporter, LacY. Transports lactose, melibiose, thio-β-methyl galactopyranoside (TMG), isopropyl-β-thiogalactoside (IPTG), 4-nitrophenyl-beta-D-galactopyranoside, 4-nitrophenyl-alpha-D-galactopyranoside and galactopyranosyl-1-glycerol. Single point mutations allow transport of sucrose and maltose (King and Wilson 1990).  Crystal structures and modeling reveal the cytoplasmic open state and the periplasmic open state (PDB ID: 1PV7). A structure with a bound lactose homolog, beta-D-galactopyranosyl-1-thio-beta-D-galactopyranoside, revealed the sugar-binding site in a cavity, and residues that play major roles in substrate recognition and proton translocation were identified (Abramson et al., 2003Pendse et al., 2010). The membrane lipid composition determines the topology of LacY (Dowhan and Bogdanov, 2011). Smirnova et al. (2011) have provided evidence that the opening of the periplasmic cavity in LacY is the limiting step for sugar binding. Evidence for an alternating sites mechanism of transport has been summarized (Smirnova et al., 2011). Eames and Kortemme (2012) have shown that when considering expression of the lac operon, LacY function (H+ co-transport) and not protein production is the primary origin of cost fitness. Homology threading of several MFS porters based on the LacY 3-d structure has been reported (Kasho et al., 2006). The alternating-access mechanism has been suggested to arise from inverted topological repeats (Radestock and Forrest, 2011; Madej et al. 2012), but this proposal has been contested (Västermark and Saier 2014; Västermark et al. 2014). Mechanistic features of LacY have been summarized (Kaback 2015). Insertion into the membrane depends on YidC (TC# 2.A.9.3.1) and may occur in a stepwise, stochastic manner employing multiple coexisting pathways to complete the folding process (Serdiuk et al. 2017). The glucose Enzyme IIA (Crr) protein binds LacY to allosterically inhibit its activity, promoting inducer exclusion (Hoischen et al. 1996; Hariharan et al. 2015). Protonated LacY binds D-galactopyranosides specifically, inducing an occluded state that can open to either side of the membrane (Kumar et al. 2014). LacY can form amyloid-like fibrils under destabilizing conditions (Stroobants et al. 2017). Multiple conformations of LacY have been solved (Kumar et al. 2018).  Direct interactions between LacY and its lipid environment uniquely contribute to its membrane protein organization and function (Vitrac et al. 2020). The lactose permease purified from E. coli exhibiting varied phospholipid compositions has the same topology and function as in its membrane of origin (Vitrac et al. 2019).



LacY of E. coli


Raffinose:H+ symporter, RafB, can be mutated to transport maltose (Van Camp et al., 2007).


RafB of E. coli


Sucrose:H+ symporter, CscB, also transports maltose (Peng et al. 2009). CscB recognizes not just sucrose but also fructose and lactulose, but glucopyranosides are not transported and do not inhibit sucrose transport (Sugihara et al. 2011). Direct interactions between LacY and its lipid environment uniquely contribute to its membrane protein organization and function (Vitrac et al. 2020).


CscB of E. coli


Melibiose:H+ symporter, MelY (Shinnick et al., 2003). Transports melibiose and lactose, but not TMG, which does however bind to the transporter (Tavoulari and Frillingos, 2008)


MelY of Enterobacter cloacae


MFS transporter specific for fructooligosaccharides, FosT, of 412 aas and 12 TMSs (Schouler et al. 2009).

FosT of E. coli


2.A.1.50 The Proton Coupled Folate Transporter/Heme Carrier Protein (PCFT/HCP) Family


TC#NameOrganismal TypeExample

The apical intestinal and choroid plexus proton-coupled, high affinity folate transporter, the hereditary folate malabsorption (HFM) protein, PCFT/HCP1 (Shin et al. 2010).  Also reported to mediate heme-iron uptake from the gut lumen with duodenal epithelial cells (Shayeghi et al., 2005; Latunde-Dada et al., 2006; Subramanian et al., 2008, Shin et al., 2012b), but it shows a higher affinity for folate than heme) (Qiu et al., 2006). Responsible for folate uptake by choroid plexus epithelial cells (Wollack et al., 2007) and placenta (Yasuda et al., 2008). The rat orthologue (Q5EBA8) catalyzes H+-dependent folate uptake in the intestine (Inoue et al., 2008; Zhao and Goldman, 2007; Qiu et al., 2006; Shin et al., 2012). Evidence for a 12 TMS topology with a renetrant loop between TMSs 2 and 3 has been presented (Zhao et al., 2010; Qiu et al., 2006; Zhao et al., 2011; Wilson et al. 2014).  Downregulated in Chronic Kidney Disease (CKD) in heart, liver, and brain, causing malabsorption (Bukhari et al., 2011). An IGXXG motif in TMS5 is important for folate binding and a GXXXG motif is involved in dimerization (Zhao et al., 2012). It is inhibited by bicarbonate, bisulfite, nitrite and other anions (Zhao et al. 2013).  Its role in antifolate cancer chemotherapy has been reviewed (Matherly et al. 2014). TMSs 3 and 6 may provide critical interfaces for formation of hPCFT oligomers, facilitated by the GXXXG motifs in TMS2 and TMS4 (Wilson et al. 2015).  The extracellular gate has been identified (Zhao et al. 2016), and mechanistic aspects have been considered (Date et al. 2016). Residues in the seventh and eighth TMSs play roles in the translocation pathway and folate binding (Aluri et al. 2017). The mutation, N411K-PCFT, is responsible for HFM (Aluri et al. 2018). PCFT is ubiquitously expressed in solid tumors to which it delivers antifolates, particularly pemetrexed, into cancer cells in a concentrative fashion (Zhao et al. 2018). Substitutions have been identified that lock and unlock PCFT into an inward-open conformation (Aluri et al. 2019). The nanodisc lipid composition influences the cell-free expression of PCFT (Do et al. 2021). Iron deficiency promotes hepatocellular carcinoma metastasis, and the loss of SLC46A1 expression leads to iron deficiency in liver tumor tissues (Wang et al. 2022). Cell-free expression of PCFT in the presence of nanodiscs has been reported (Do and Jansen 2022). Biological and therapeutic applications of the proton-coupled folate transporter have been reviewed (Matherly et al. 2022).


SLC46A1 or PCFT of Homo sapiens

2.A.1.50.2Thymic stromal cotransporter, TSCOT (Kim et al. 2000)AnimalsSLC46A2 of Homo sapiens
2.A.1.50.3 solute carrier family 46, member 3AnimalsSLC46A3 of Homo sapiens

Multidrug efflux transporter, MET, of 507 aas and 12 TMSs (Chahine et al. 2012).  Exposure to dietary methotrexate was associated with increased fluid secretion rate and increased flux of methotrexate, but not salicylate. Exposure to methotrexate in the diet resulted in increases in the expression of a multidrug efflux transporter gene (MET; CG30344) in the Malpighian tubules. There were also increases in expression of genes for either a Drosophila multidrug resistance-associated protein (dMRP; CG6214; TC# 3.A.1.208.39) or an organic anion transporting polypeptide (OATP; CG3380; TC# 2.A.60.1.27), depending on the concentration of methotrexate in the diet.  MET probably does not export methotrexate (Chahine et al. 2012).

MET of Drosophila melanogaster (Fruit fly)


2.A.1.51 The Uncharacterized Major Facilitator-7 (UMF7) Family

This family may include aromatic acid porters.


TC#NameOrganismal TypeExample
2.A.1.51.1Putative permeaseBacteriaPutative transporter of Azoarcus sp. EbN1 (CAI06874)

YjiJ MFS porter, a member of the DUF2118 family in Pfam.


YjiJ of E. coli (D6IHN4)


MFS permease


MFS permease of Thermus thermophilus (F6DF77)


Uncharacterized MFS permease


UP of Pseudomonas aeruginosa


2.A.1.52 The Glycerophosphodiester Uptake (GlpU) Family


TC#NameOrganismal TypeExample

MFS permease, YihN, of 423 aas and 11 TMSs.  It may transport aromatic fluorophores (fluorescent dyes) (Salcedo-Sora et al. 2021).


YihN of E. coli (P32135)


YqcE putative transporter


YqcE pf E. coli (F4TJX1)


MFS permease


MFS permease of Propionibacterium acnes


The glycerophosphodiester, glycerophosphocholine uptake porter, GlpU.  The cytoplasmic compound is hydrolyzed to α-glycerolphosphate and choline (Großhennig et al. 2013).


GlpU of Mycoplasma pneumoniae


2.A.1.53 The Proteobacterial Intraphagosomal Amino Acid Transporter (Pht) Family


TC#NameOrganismal TypeExample
2.A.1.53.1The threonine uptake permease, PhtA (Sauer et al., 2005) (required for maximal growth in macrophages and Acanthamoeba castellanii)Gamma proteobacteriaPhtA of Legionella pneumophila (YP_094583)

PhtF of 425 aas

PhtF of Legionella pneumophila


PhtG of 432 aas

PhtG of Legionella pneumophila


PhtH of 430 aas

PhtH of Legionella pneumophila


PhtI of 390 aas

PhtI of Legionella pneumophila


PhtK of 410 aas

PhtK of Legionella pneumophila


The valine uptake permease, PhtJ (required for maximal growth in macrophages and Acanthamoeba castellanii) (Chen et al., 2008)

Gamma proteobacteria

PhtJ of Legionella pneumophila (YP_095910)


The MFSD1 (SMAP4) transporter (465 aas; 12 TMSs).  Expression is increased in mice by amino acid starvation and decreased by a high fat diet (Perland et al. 2016). This lysosomal transporter is essential for liver homeostasis and critically depends on its accessory subunit GLMP (Massa López et al. 2019). MFSD1 is not N-glycosylated but contains a dileucine-based sorting motif needed for its transport to lysosomes. Mfsd1 knockout mice develop splenomegaly and severe liver disease. GLMP (406 aas and at least 2 TMSs, N- and C-terminal) physically interacts with MFSD1 and is a critical accessory subunit. GLMP is essential for the maintenance of normal levels of MFSD1 in lysosomes and vice versa. Glmp knockout mice mimic the phenotype of Mfsd1 knockout mice (Massa López et al. 2019).  The two lysosomal integral membrane proteins MFSD1 and GLMP form a tight complex that confers protection of both interaction partners against lysosomal proteolysis. López et al. 2020 refined the molecular interaction of the two proteins and found that the luminal domain of GLMP alone, but not its transmembrane domain or its short cytosolic tail, conveys protection and mediates the interaction with MFSD1. The interaction is essential for the stabilization of the complex. N-glycosylation of GLMP is essential for protection. The interaction of both proteins   starts in the endoplasmic reticulum, and quantitatively depends on each other. Both proteins can affect their intracellular trafficking to lysosomes. MFSD1 can form homodimers both in vitro and in vivo (López et al. 2020).


MFSDI/GLMP of Homo sapiens (A6NID9)


Uncharacterized protein of 575 aas and 14 TMSs.


UP of Cyanidioschyzon merolae


Putative amino acid transporter of 478 aas and 12 TMSs, CG8602, isoform A.  May play a role in macrophage migration in the Drosophila embryo (Dr. Daria Siekhaus, personal communication).

SG8602A of Drosophila melanogaster (Fruit fly)


MFS uptake permease specific for pyrimidines, PhtC of 422 aas and 12 TMSs.  Together with PhtD (TC# 2.A.1.53.6), it contributes to protection of L. pneumophila from dTMP starvation, protects the cell from 5-fluorodeoxyuridine (FUdR) toxicity and is required for growth of L. pneumophila in macrophage (Fonseca et al. 2014).

PhtC of Legionella pneumophila


MFS uptake permease, probably specific for pyrimidines, PhtD of 427 aas and 12 TMSs.  Together with PhtC (TC# 2.A.1.53.6), it contributes to protection of L. pneumophila from dTMP starvatioin, protects the cell from 5-fluorodeoxyuridine (FUdR) toxicity and is required for growth of L. pneumophila in macrophage (Fonseca et al. 2014).

PhtD of Legionella pneumophila


PhtB of 431 aas

PhtB of Legionella pneumophila


PhtE of 430 aas

PhtE of Legionella pneumophila


2.A.1.54 The Uncharacterized Major Facilitator-9 (UMF9) Family

The proteins of this family are related to 2.A.1.54; amino acid/nucleobase porters. Members are mainly found in bacteria and archaea.


TC#NameOrganismal TypeExample

The archaeal uptake permease, MMP0835 (function unknown) (31% I, 49% S with PhtA)


MMP0835 of Methanococcus maripaludis (CAF30391)


UMF-9 homologue of 414 aa


UMF9 homologue of Geobacter sulfurreducens (Q747F2)


Functionally uncharacterized MFS porter of 414 aas

UP of Syntrophothermus lipocalidus


2.A.1.55 The Uncharacterized Major Facilitator-8 (UMF8) Family

These systems may be MDR pumps.


TC#NameOrganismal TypeExample

Uncharacterized MFS porter of 397 aas and 12 TMSs

UP of Halorubrum distributum


Uncharacterized protein of 390 aas

UP of Natrinema versiforme


Uncharacterized protein of 406 aas

UP of Haloterrigena salina


Putative phthalate porter of 377 aas

UP of Haloferax gibbonsii


MFS protein of 373 aas and 11 TMSs. The protein is probably N-terminally truncated due to an error, and probably has 12 TMSs in a 6 + 6 TMS arrangement.

MFS porter of Labrenzia sp. THAF82


2.A.1.56 The 1,3-Dihydroxybenzene/Drug Transporter (DHB-T) Family


TC#NameOrganismal TypeExample

The 1,3-dihydroxybenzene (resorcinol) uptake permease, MFS_1 (Darley et al., 2007) of 402 aas and 12 TMSs.


MFS_1 of Azoarcus anaerobius (YP_285101)


Uncharacterized protein of 405 aas and 12 TMSs.


UP of Bradyrhizobium japonicum


2.A.1.57 The Ferripyochelin Transporter (FptX) Family


TC#NameOrganismal TypeExample

The Ferripyochelin uptake permease, FptX (Michel et al., 2007).  Also transports N-acetylglucosamine anhydrous N-acetylmuramyl peptides and is called AmpP or AmpGh1 (Kong et al. 2010).  However, it does not play a role in the induction of β-lactam resistance (Zhang et al. 2010).


FptX or AmpP of Pseudomonas aeruginosa (Q9HWG8)


The ferric rhizbactin 1021 uptake porter, RhtX (Cuív et al. 2004).


RhtX of Sinorhizobium meliloti


Iron-yersiniabactin (Ybt) transporter of 467 aas and 12 TMSs, YbtX (Bobrov et al. 2014). Yersiniabactin can also bind zinc ions with high affinity and feed the Zn2+ into this MFS transporter, YbtX (Bobrov et al. 2014). In fact, the siderophore, Ybt, is required for growth under Zn2+-deficient conditions in a strain lacking ZnuABC (see 3.A.1.15.5 for the E. coli ortholog). This MFS porter is similar to the Irp8 piscibactin secretion porter of Vibrio anguillarum (Lages et al. 2022).


YbtX of Yersinia pestis


Siderophore transporter, RhtX/FptX family


Siderophore transporter of Myxococcus xanthus


The iron (Fe3+)·pyridine-2,6-bis(thiocarboxylic acid (PDTC)) uptake transporter, PdtE. Functions with the OMR, PdtK, 1.B.14.8.2 (most similar to 2.A.1.57.4) (Leach and Lewis 2006).


PdtE of Pseudomonas putida (ABC8353)


Major facilitator superfamily domain-containing protein 3, MFSD3. Function unknown. The human ortholog has Uniprotein acc # of Q96ES6 with 412 aas and 12 TMSs.


Mfsd3 of Rattus norvegicus


2.A.1.58 The N-Acetylglucosamine Transporter (NAG-T) Family


TC#NameOrganismal TypeExample

The N-acetylglucosamine:H+ symporter, Ngt1 (Alvarez and Konopka, 2007)


Ngt1 of Candida albicans (Q5A7S4)


May contribute to coordination of muscle contraction as regulatory subunit of a nonessential potassium channel complex.  Subunit structure:  May form a complex with sup-9 and sup-10 where unc-93 and sup-10 act as regulatory subunits of the two pore potassium channel sup-9.



Unc-93 of Caenorhabditis elegans (Q93380)


UNC93-like protein MFSD11 (Major facilitator superfamily domain-containing protein 11; Protein ET) of 449 aas and 12 TMSs It seems to be involved in intracellular transport in mammals and has been suggested to be a sugar:H+ symporter (Zhang et al. 2018). It is expressed in testis, small intestine, spleen, prostate, and ovary, and mutations can give rise to ovarian cancer (Liu et al. 2002). Mfsd11 is abundantly expressed in the mouse brain and plays a potential role in energy homeostasis (Perland et al. 2016). Its transcript is highly enriched in Aedes aegypti during arbovirus infection (Campbell et al. 2011). UNC93A and SV2 (TC# 2.A.1.22.1) may play a role in virus assembly or budding (Campbell et al. 2011). TMEM132C, UNC93A and TTLL2 (the latter two genes being adjacent) are associated with pulmonary function (Son et al. 2015). It may be involved in psoriasis, a common chronic autoimmune inflammatory skin disease (Li et al. 2020).


MFSD11 of Mus musculus


MFS permease of 467 aas


MFS permease of Oryza sativa


Duf895 protein of 450 aas


Duf895 protein of Verticillium albo-atrum


MFS permease of 425 aas

Slime molds

MFS permease of Dictyostellium discoideum


Unc-93 family homologue B1, Unc-93b1 or Unc93b1, of 597 aas and 12 TMSs, plays a role in innate and adaptive immunity by regulating nucleotide-sensing Toll-like receptor (TLR) signaling (Pelka et al. 2014). It is required for the transport of a subset of TLRs (including TLR3, TLR7 and TLR9) from the endoplasmic reticulum to endolysosomes where they can engage pathogen nucleotides (e.g., of viral nucleic acids) and activate signaling cascades. Unc93B1 may play a role in autoreactive B-cells removal (Isnardi et al. 2008).  It induces apoptotic cell death and is cleaved by host and viral proteases (Harris and Coyne 2015). UNC93B1 may play a role in human oral squamous cell carcinomas growth by controlling the secretion of granulocyte macrophage colony-stimulating factor (GM-CSF) (Wagai et al. 2019). UNC93B1 regulates Toll-like receptor stability independently of endosomal TLR transport (Pelka et al. 2018). A missense variant affecting the C-terminal tail of UNC93B1 in dogs is responsible for a Exfoliative Cutaneous Lupus Erythematosus (ECLE) condition (Leeb et al. 2020). Compartmentalization of TLRs in the endosome limits their activation by self-derived nucleic acids and reduces the possibility of autoimmune reactions. UNC93B1 is indispensable for the trafficking of TLRs from the endoplasmic reticulum to the endosome. Ishida et al. 2021 reported two cryo-EM structures of human and mouse TLR3-UNC93B1 complexes and a human TLR7-UNC93B1 complex. UNC93B1 exhibits structural similarity to other MFS porters. Both TLRs interact with the UNC93B1 amino-terminal six-helix bundle through their transmembrane and luminal juxtamembrane regions, but the complexes of TLR3 and TLR7 with UNC93B1 differ in their oligomerization state (Ishida et al. 2021). The mammalian trafficking chaperone protein UNC93B1 maintains the ER calcium sensor STIM1 in a dimeric state primed for translocation to the ER cortex (Wang and Demaurex 2022).


Unc93b1 of Homo sapiens


MFS permease of 418 aas and 12 TMSs.

MFS permease of Entamoeba histolytica


Unc93A of 457 aas and 12 TMSs.

Unc93A of Homo sapiens


2.A.1.59 The Uncharacterized Major Facilitator-10 (UMF10) Family

These porters are mostly from Archaea but some are from bacteria; they are closely related to 2.A.1.46, possible drug exporters.


TC#NameOrganismal TypeExample

UMF10a of unknown function, (COG2270).


UMF10a of Methanococcus aeolicus (A6UVW2)


UMF10b (in an operon with a sensor kinase/response regulator pair and an 8 TMS rhomboid protease)


UMF10b of Nostoc punctiforme (B2JBG5)


MFS permease, AF1541


AF1541 of Archaeoglobus fulgidus (O28731)


MFS permease, LepA


LepA of Hydrogenivirga sp.128-5-R1-1 (A8UT57)


Putative pantothenate:H+ importer of 417 aas and 12 TMSs (Wunderlich 2022).

Putative pantothenate uptake porter of Plasmodium falciparum


2.A.1.6 The Metabolite:H+ Symporter (MHS) Family


TC#NameOrganismal TypeExample
2.A.1.6.1Citrate:H+ symporterBacteriaCitA of Klebsiella pneumoniae

Inner membrane metabolite transport protein YhjE


YhjE of Escherichia coli


Acetate/haloacid transporter, Dehp2, with a possible atypical topology (Tse et al. 2009).  Transports acetate, chloroacetate, bromoacetate, 2-chloropropionate, and possibly, with low affinity, glycolate, lactate and pyruvate (based on weak inhibition results).  Inducible by chloroacetate (Su and Tsang 2012).  This protein is 79% identical to its paralogue, Deh4p (TC# 2.A.1.6.8) which differs in that it shows lower apparent affinity for 2-chloropropionate.


Dehp2 of Burkholderia caribensis (formerly sp. MBA4)


The putative thiazole transporter, ThiU. Regulatyed by TPP riboswitch (Rodionov et al. 2002)


ThiU of Haemophilus influenzae (P44699)


Acetate/monochloroacetate permease, Deh4p, of 468 aas and 12 TMSs.  Transports various carboxylates.  Dehalococcoides mccartyi degrades haloacids (Su et al. 2016).

Deh4p of Dehalococcoides mccartyi


Proline/glycine betaine uptake transporter, ProP, of 466 aas and 12 TMSs. It is not the major proline transporter found in S. aureus (Lehman et al. 2023).

ProP of Staphylococcus aureus


α-Ketoglutarate (oxoglutarate):H+ symporter (Seol and Shatkin 1992; Seol and Shatkin 1992).  May also export arabinose but not xylose (Koita and Rao 2012).


KgtP of E. coli (P0AEX3)


Dicarboxylate:H+ symporter.  Transports and serves as a chemoreceptor for β-ketoadipate (Karimian and Ornston 1981).


PcaT of Pseudomonas putida


(Proline/glycine-betaine):(H+/Na+) symporter, ProP (also transports taurine, ectoine, pipecolate, proline-betaine, N,N-dimethylglycine, carnitine, and 1-carboxymethyl-pyridinium) (subject to osmotic activation). Transmembrane helix I and periplasmic loop 1 are involved in osmosensing and osmoprotectant transport (Keates et al., 2010). ProP detects the increase in cytoplasmic cation concentration associated with osmotically induced cell dehydration and mediates osmolyte uptake into bacteria (Ozturk et al. 2020). ProP is a 12-TMS protein with an α-helical, cytoplasmic C-terminal domain (CTD) linked to TMS XII. The CTD helix associates with the anionic membrane surface to lock ProP in an inactive conformation. The release of the CTD may activate ProP. Molecular dynamics simulations showed specific intrapeptide salt bridges forming when the CTD associated with the membrane. The salt bridge Lys447-Asp455 weakened CTD-lipid interactions at 0.25 M KCl, and gradual stiffening of the membrane with increasing salinity was obseerved. Thus, salt cations may affect CTD release and activate ProP by increasing the order of membrane phospholipids (Ozturk et al. 2020). ProP forestalls cellular dehydration by detecting environments with high osmotic pressure and mediating the accumulation of organic osmolytes by bacterial cells. Structural determinants and functional significance of dimerization have been described (Ozturk et al. 2023).


ProP of E. coli (P0C0L7)

2.A.1.6.54-Methyl-o-phthalate:H+ symporterBacteriaMopB of Burkholderia cepacia
2.A.1.6.6Shikimate:H+ symporterBacteriaShiA of E. coli
2.A.1.6.7The citrate/tricarballylate:H+ symporter (CitA or TcuC); probably orthologous to 2.A.1.6.1 (Lewis et al., 2004)BacteriaTcuC of Salmonella enterica serovar Typhimurium LT2 (P0A2G3)

The acetate/monochloroacetate (haloacid) permease, Deh4p (Km = 5.5 mμM for acetate; 9 mμM for monochloroacetate) (Yu et al., 2007; Su and Tsang 2012).


Deh4 of Burkholderia cepacia or sp. MBA4 (Q7X4L6)


YdfJ. Can function as an inward rectifying K+ channel when expressed in animal cells as measured by whole cell patch clamping. Blocked by barium and protopine (Tang et al., 2011).


YdfJ of E. coli (P77228)


2.A.1.60 The Rhizopine-related MocC (MocC) Family


TC#NameOrganismal TypeExample
2.A.1.60.1The rhizopine related transporter, MocC (could either transport a precursor for rhizopine biosynthesis into bacteroids or the finished product from the bacteroids) (Murphy et al., 1993)BacteriaMocC of Sinorhizobium meliloti (Q07609)

Inner membrane protein YbjJ


YbjJ of Escherichia coli


The multidrug (quinolone; tetarcycline) resistance pump, TcrA (Chang et al. 2011).


TcrA of Stenotrophomonas maltophilia (F2WVP9)


2.A.1.61 The Microcin C51 Immunity Protein (MccC) Family

May also export various drugs.


TC#NameOrganismal TypeExample
2.A.1.61.1The MccC microcin C51 immunity protein (exports the peptide-nucleotide 'Trojan horse' antibiotic) (Fomenko et al., 2003; Kazakov et al., 2007)BacteriaMccC of E. coli (Q83Y57)

MFS porter of 411 aas and 12 TMSs.

Porter of Bartonella washoensis


MFS porter of 413 aas and 12 TMSs.

Porter of Parachlamydia acanthamoebae


2.A.1.62 The Uncharacterized Major Facilitator-11 (UMF11) Family

Possibly involved in transport of amino acids and their derivatives.


TC#NameOrganismal TypeExample

The UMF11 homologue


UMF11 of Staphylococcus aureus (A8YZ14)


Putative Macrolide efflux pump (P-MEP), possibly involved in transport of amino acids and their derivatives.



P-MEP of Fusobacterium sp. 7_1 (C3WVU9)


UMF11 (links UMF11 with UMF13)


UMF11 of Bacillus clausii (Q5WGH2)


Uncharacterized protein of 406 aas and 12 TMSs.  Gives an alignment with a ferroportin homolog, 2.A.100.2.1 including almost all of both proteins with a TC BLAST score of e-12.

UP of Clostridium diolis


Putative MFS efflux pump of 389 aas and 12 TMSs. Expression of the gene encoding this transporter is governed by a quorum sensing (QS) system, and it impacts the expression of multiple virulence factors, accounting for QS-dependent antibiotic susceptibility (Chang et al. 2022).

MFS porter of Streptococcus pyogenes


2.A.1.63 The Uncharacterized Major Facilitator-12 (UMF12) Family

May export drugs.


TC#NameOrganismal TypeExample

The UMF12 protein 


UMF12 of Methanosarcina barkeri (Q467Y6)


UMF12 Possible amino acid exporter


UMF12 of Methanosarcina mazei (Q8PRW9)


Possible nucleotide or oligonucleotide uptake porter, UMF12


UMF12 of Deinococcus radiodurans (Q9RXM0)




MFS carrier


MFS carrier of Saccharomyces cerevisiae K7 (P47159)


2.A.1.64 The Unidentified Major Facilitator-13 (UMF13) Family

Similar to 2.A.1.62; may transport amino acids and their derivatives.


TC#NameOrganismal TypeExample

The UMF13 protein


UMF13 of Streptococcus thermophilus (Q5M4L1)

2.A.1.64.2Uncharacterized protein RP255BacteriaRP255 of Rickettsia prowazekii

Uncharacterized protein of 611 aas

UP of Spiroplasma diminutum


2.A.1.65 The Uncharacterized Major Facilitator-14 (UMF14) Family

Possibly this family includes members that transport metabolites such as aromatic acids.


TC#NameOrganismal TypeExample

The putative MFS carrier, Sugar Baby (Sug, isoform D); has a hydrophilic domain between TMSs 3 and 4. Overexpression causes an increased lifespan by 17%. It has 12 TMSs in a 3 + 3 + 6 TMS arrangement.


Sugar Baby of Drosophila melanogaster (Q7KUF9)


Major facilitator superfamily domain-containing protein 6-like, MfsD6Ls, of 586 aas and 12 TMSs. Mutations can cause pediatric cataracts (Aldahmesh et al. 2012).


MFSD6L of Homo sapiens


Duplicated MFS permease (901 amino acyl residues; ~24 TMSs)


Duplicated MFS permease of Chlamydomonas reinhardtii


MFS_1_like domain-containing protein, MFSD6, of 630 aas and 12 TMSs in a 3 + 3 + 6 TMS arrangement. It seems to regulate neural circuit activity (McCulloch et al. 2017).

MfsD6 of Caenorhabditis elegans


MFSD6 of 791 aas and 12 TMSs in a 3 + 3 + 6 TMS arrangement. Mutations in the mfsd-6 gene influence the regulation of  neural circuit activity (McCulloch et al. 2017). MfsD6 may transport sugars.

MfsD6 of Homo sapiens

2.A.1.65.2Unknown MFS homologue; e-6 with 2.A.1.5 family members; has a hydrophilic domain between TMSs 3 and 4.


UMF14 of Culex quinquefasciatus (B0W435)


Unknown MFS homologue UMF14 ( 833 aas, 12 TMSs in a 3+9 arrangement )


UMF14 of Anopheles gambiae (Q7Q0Z9)


Uncharacterized protein of 474 aas


UP of Nematostella vectensis (Starlet sea anemone)


MFS porter


MFS porter of Daphnia pulex (E9I268)


Macrophage MHC Class I receptor 2, Mmr2 or MFSD6.  The ortholog of this protein in humans is a also called MFSD6 and is 90% identical to the mouse protein (Bagchi et al. 2020). This disease protein shows increased expression levels with increased energy consumption (Bagchi et al. 2020).


Mmr2 of Mus musculus (Q8CBH5)


MFS porter


MFS porter of Chlorella variablis (E1ZG13)


MFS permease


MFS permease of Thermoanaerobacter tengcongensis (Q8R7B7)

2.A.1.65.9Maltose permease


MalA of Geobacillus stearothermophilus


2.A.1.66 The Uncharacterized Major Facilitator-15 (UMF15) Family

Most similar to family 2.A.1.49 which functions to transport sphingosine-1-P or sphingosyl lipids.


TC#NameOrganismal TypeExample

MFS permease of unknown function (First half resembles 2.A.1.3.7 (e-11) and 2.A.1.15.3 (e-8)). Very likely to be a galactoside/galactose transporter; encoded within a gene cluster with β-galactosidase and galactose metabolic genes.


MFS permease of Thermofilum pendens (A1RW34)


Putative 4-hydroxybenzoate uptake transporter, MFS_1 (in an operon with 2,3-diketo-5-methylthiopentyl-1-phosphate enolase-phosphatase of the methionine salvage pathway), using S-adenyl methionine (SAM) as substrate. May transport SAM.


MFS1 of Leptospira interrogans (Q8F7L4)


UMF15 Homologue

Eukaryotes (Stramenophiles)

UMF15 homologue of Thalassiosira pseudonana (B8BU21)



MFS transporter of 531 aas.  Present in the membrane of the organelle called the rhoptries which is involved in host invasion and hijacking host cell functions (Peter Bradley, personal communication).


MFS porter of Toxoplasma gondii


MFS transporter of 428 aas.  Present in the membrane of the organelle called the rhoptries which is involved in host invasion and hijacking host cell functions (Peter Bradley, personal communication).


Porter of Toxoplasma gondii


Uncharacterized protein of 646 aas and 12 TMSs

UP of Chlorella variabilis (Green alga)


Putative MFS carrier of 809 aas and 12 TMSs in a 2 + 4 + 6 TMS arrangement.

MFS carrier of Plasmodium falciparum


Pantothenate:H+ symporter, PAT or TMP1 of 565 aas and 12 TMSs in a 6 + 6 TMS arrangement (Wunderlich 2022).

PAT of Plasmodium falciparum


2.A.1.67 The Uncharacterized Major Facilitator-16 (UMF16) Family

Most similar to 2.A.21,39 and 51; may export drugs, aromatic acids and/or siderophores


TC#NameOrganismal TypeExample

MFS permease of unknown function (second half distantly resembles the first half of 2.A.1.41.3/e value of 0.001)


UMF16 of Kribbella flavida (D2PP09)


MFS porter


MFS porter of Arthrobacter aurescens (A1R564)


MFS porter


MFS porter of Erwinia pyrifoliae (D0FNI7)


MFS porter of 402 aas and 12 TMSs.


MFS porter of Propionibacterium acnes (D1YEI1)


MfsB (Smlt0548) (B2FL18) of 404 aas and 12 TMSs in a 6 + 6 TMS arrangement.  Its function is not known (Boonyakanog et al. 2022).

MfsB of Stenotrophomonas maltophilia


2.A.1.68 The Glucose Transporter (GT) Family


TC#NameOrganismal TypeExample

The glucose transporter, OEOE_1574; does not transport fructose (Kim et al., 2011).


OEOE_1574 of Oenococcus onei (Q04DP6)


MFS porter of 409 aas

MFS porter of Methanofollis ethanolicus


MFS porter

MFS porter of Blautia producta


2.A.1.69 The Uncharacterized Major Facilitator-17 (UMF17) Family


TC#NameOrganismal TypeExample

The UMF17A porter


UMF17A porter of Streptomyces coelicolor (Q9KZY0)


MFS permease of 438 aas

MFS porter of Geodermatophilus obscurus


2.A.1.7 The Fucose: H+ Symporter (FHS) Family


TC#NameOrganismal TypeExample

L-Fucose:H+ symporter. The x-ray structure (3.1Å resolution) with an outward open, amphipathic cavity has been solved. Asp46 and Glu135 can undergo cycles of protonation (Dang et al., 2010). 


FucP of E. coli


The putative glucose porter, GlcP (Rodionov et al., 2010).


GlcP of Shewanella amazonensis (A1S5F4)


The putative mannose porter, ManPl (Rodionov et al., 2010).


ManPl of Shewanella amazonensis (A1S297)


The putative trehalose porter, TreT (Rodionov et al., 2010)


TreT of Shewanella frigidimarina (Q07XD1)

2.A.1.7.13Bypass of stop codon protein 6FungiBSC6 of Saccharomyces cerevisiae S288c

Protein TsgA, also called GutS, YhfC, YhfH.  tsgA i(gutS) gene expression is up-regulated by tellurite and selenite (Guzzo and Dubow 2000).


TgsA of E. coli


Major facilitator superfamily domain-containing protein 4-A, MFSD4A, of 526 aas and 12 TMSs.


MfsD4a of Danio rerio


The putative mannose porter, ManP (Rodionov D.A., personal communication). Regulated by mannose regulon ManR.


ManP (Q8A5Y0) of Bacteroides thetaiotaomicron


The putative fructose porter, FruP (Rodionov D.A., personal communication). Regulated by fructose oligosaccharide utilization regulon.


FruP (Q8A6W8) of Bacteroides thetaiotaomicron


The putative N-acetylglucosamine porter, NagP (Rodionov D.A., personal communication). Regulated by heparin utilization regulon.


NagP (Q89YS8) of Bacteroides thetaiotaomicron


Probable glucose transporter encoded by a gene sandwiched in between two genes encoding a glucose 1-dehydrogenase and a gluconolactonase.


Glucose permease of Parachlamydia acanthamoebae

2.A.1.7.2Glucose/galactose porterBacteriaGgp of Brucella abortus (P0C105)

Uncharacterized MFS protein of 392 aas and 12 TMSs.

UMFS of Bdellovibrio exovorus


Uncharacterized protein of the MFS of 505 aas and 12 TMSs

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Uncharacterized protein of 494 aas and 12 TMSs.

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Na+-dependent glucose transporter 1, Mfsd4b, of 491 aas and 12  TMSs.  May also serve as a channels for urea in the inner medulla of the kidney.

Mfsd4b of Xenopus laevis (African clawed frog)


MFS porter, MFSD4a or SLC60A1, of 514 aas and 12 TMSs. In the mouse, this protein and MFSD9 localize to neurons in the brain, and their mRNA expression levels are affected by diet (Perland et al. 2017). They are associated with cancer and have anti-tumor activities (Yang et al. 2022). It may play a role in the excretion of nitrogen metabolites (Honerlagen et al. 2021).

MFSD4a of Homo sapiens


Uncharacterized protein of 894 aas and 19 TMSs in a 7 + 12 TMS arrangement.  The first 7 TMSs comprise a CFEM domain, while the last 12 TMSs are homologous to MFS porters. There are many such proteins in the NCBI database, most from fungi.

UP of Leptosphaeria maculans


Na+:glucose co-transporter of 672 aas and about 14 TMSs, SGLT2. It has a Na+ to glucose coupling ratio of 1:1 (Brown et al. 2019). Efficient substrate transport in the mammalian kidney is provided by the concerted action of a low affinity high capacity and a high affinity low capacity Na+/glucose cotransporter arranged in series along kidney proximal tubules. Inhibitors are antidiabetic agents (Li 2019; Singh and Singh 2020). They are also useful as theraputic agents of non-alcoholic fatty liver disease and chronic kidney disease (Kanbay et al. 2020). Marein, an active component of the Coreopsis tinctoria Nutt plant, ameliorates diabetic nephropathy by inhibiting renal sodium glucose transporter 2 and activating the AMPK signaling pathway (Guo et al. 2020). NHE-3 (TC# 2.A.53.2.18) was markedly downregulated, while the Na+-HCO3--cotransporter (NBC-1; TC# 2.A.31.2.12) and SGLT2 were upregulated after kidney transplantation (Velic et al. 2004). Pharmacological inhibition of hSGLT2 by oral small-molecule inhibitors, such as empagliflozin, leads to enhanced excretion of glucose and is widely used in the clinic to manage blood glucose levels for the treatment of type 2 diabetes. Niu et al. 2021 determined the cryogenic electron microscopic structure of the hSGLT2-MAP17 complex in the empagliflozin-bound state to a resolution of 2.95 Å. MAP17 interacts with transmembrane helix 13 of hSGLT2. Empagliflozin occupies both the sugar-substrate-binding site and the external vestibule to lock hSGLT2 in an outward-open conformation, thus inhibiting the transport cycle (Niu et al. 2021). There is no upregulation regarding host factors potentially promoting SARS-CoV-2 virus entry into host cells when the SGLT2-blocker empagliflozin, telmisartan and the DPP4-inhibitor blocker, linagliptin, are used (Xiong et al. 2022). Canagliflozin, dapagliflozin and ipragliflozin significantly inhibit the growth of different cancer cell lines in the micromolar range; SGLT2 inhibitors have antiproliferation, anti-tumorigenesis, and anti-migration effects and may induce apoptosis in cancer cells. Treatment with SGLT2 inhibitors also results in the downregulation of selected genes (Bardaweel and Issa 2022). SGLT2 inhibitor treatment results in symptomatic and functional well-being, especially in relieving pain (Calderon-Rivera et al. 2022). Effects of SGLT2 inhibitors affect the heart and kidney to promote autophagic flux, nutrient deprivation signaling and transmembrane sodium transport (Zannad et al. 2022). Empagliflozin (EMPA), mainly acting on SGLT2, prevented DNA methylation changes induced by high glucose and provided evidence of a new mechanism by which SGLT2i can exert cardio-beneficial effects (Scisciola et al. 2023). A diversifiable synthetic platform for the discovery of new carbasugar SGLT2 inhibitors using azide-alkyne click chemistry has been described (Kitamura et al. 2023). SGLT2 is inhibited by empagliflozin (Raven et al. 2023). SGLT2 inhibitors not only suppress hyperglycemia but also reduce renal, heart, and cardiovascular diseases (Unno et al. 2023). In fact, SGLT2 may also be related to other functions, such as bone metabolism, longevity, and cognitive functions based on mouse models (Unno et al. 2023). Complex effects of different SGLT2 inhibitors on alphaKlotho gene expression (see TC family 8.A.49) and protein secretion in renal MDCK and HK-2 cells have been observed (Wolf et al. 2023). Ferulic acid-grafted chitosan (FA-g-CS) stimulates the transmembrane transport of anthocyanins by SGLT1 and GLUT2 (Ma et al. 2022). SGLT2 Inhibitors are potential anticancer agents (Basak et al. 2023). Analyses of the effects of SGLT2 inhibitors on renal tubular sodium, water and chloride homeostasis as well as their roles in influencing heart failure outcomes has appeared (Packer et al. 2023).  The SGLT2 inhibitor, empagliflozin, alleviates cardiac remodeling and contractile anomalies in a FUNDC1-dependent manner in experimental Parkinson's disease (Yu et al. 2023). Type 2 diabetes guidance proposes offering SGLT2-inhibitor therapy to people with established atherosclerotic cardiovascular disease (ASCVD) or heart failure, but this suggestion has been questioned (Young et al. 2023). SGLT2 inhibition in a non-diabetic rat model of salt-sensitive hypertension blunts the development of salt-induced hypertension independent of sex (Kravtsova et al. 2023).

GLUT2 of Homo sapiens


Na+/Glucose co-transporter, SGLT1, SLC60A2 or MfsD4B, of 518 aas and 12 TMSs (Perland et al. 2017).

MfsD4B of Homo sapiens


Glucose/Mannose/Xylose: H+ symporter (Paulsen et al., 1998; G.Gosset, personal communication).


GlcP of Bacillus subtilis


Rat kidney Na+-dependent glucose (methyl α-glucoside) transporter, NaGLT1 or SGLT1 (glucose:Na+:Na+=1:1) (Horiba et al., 2003). Position 170 of Rabbit Na+/glucose cotransporter (rSGLT1) lies in the Na+ pathway, and modulation of polarity/charge at this site regulates charge transfer and carrier turnover (Huntley et al. 2004). The fine-tuning of glucose uptake mechanisms is rendered by various glucose transporters with distinct transport characteristics. In the pancreatic islet, facilitative diffusion glucose transporters (GLUTs), and sodium-glucose cotransporters (SGLTs) contribute to glucose uptake and represent important components in the glucose-stimulated hormone release from endocrine cells, therefore playing a crucial role in blood glucose homeostasis (Berger and Zdzieblo 2020). SGLT1 and SGLT2 are therapeutic targets for various diseases (Sano et al. 2020), and function in glucose absorption in the small intestine (Vallon 2020). This glucose:Na+ symporter can transport the drug gastrodin, a seditive with a strcture of a phenolic glucoside (Huang et al. 2023).


NaGLT1 of Rattus norvegicus (BAC57446)


2-Deoxy-D-ribose porter, DeoP (Christensen et al., 2003).  Plays a role in colonization of the mouse intestine (Martinez-Jéhanne et al. 2009).


DeoP of Salmonella typhimurium LT-2 (gi 16767076)


Sucrose permease, ScrT (Rodionov et al., 2010)


ScrT of Shewanella frigidimarina (ABI73814)

2.A.1.7.7The Na+-dependent sugar transporter, HP1174 (transports glucose, galactose, mannose and 2-deoxyglucose (Psakis et al. 2009)). (most similar to 2.A.1.7.2; 49% identity)


HP1174 of Helicobacter pylori (O25788)


N-acetylglucosamine porter, NagP (Rodionov et al. 2010).


NagP of Shewanella oneidensis (Q8EBL0)


The putative N-acetylgalactosamine porter, AgaP (Leyn et al. 2012).


AgaP of Shewanella amazonensis (A1S4V0)


2.A.1.70 The Arsenite/Antimonite Exporter (ArsK) Family

One member of this family (2.A.1.70.9) has been characterized as an arsenite/antimonite exporter (Shi et al. 2018).


TC#NameOrganismal TypeExample

UMF18A,  May be a monocarboxylate uptake transporter based on its sequence similarity with families 2.A.1.11 and 2.A.1.13. 


UMF18A of Streptomyces coelicolor (Q9L223)




UMF18B of Saccharomonospora azurea (G4JJZ0)




UMF18C of Salinispora tropica (A4X2L1)


Uncharacterized MFS protein of 412 aas and 12 TMSs.

UP of Meiothermus timidus


Uncharacterized MFS porter of 401 aas and 12 TMSs.

UP of Belnapia rosea


Uncharacteerized MFS porter of 434 aas and 12 TMSs

UP of Halalkalibacillus halophilus


Uncharacterized MFS porter of 401 aas and 12 TMSs.

UP of Dehalococcoidia bacterium


Uncharacterized MFS porter of 397 aas and 12 TMSs, annotated in Uniprot as ArsP.  The encoding gene is next to genes encoding ArsH (Q1LRL2), an NADPH-dependent FMN reductase, ArsC1, an arsenate reductase (Q1LRL1) and an arsenite efflux pump, ArsB or Acr3 of 10 TMSs (ArsB; Q1LRL0; ACR family, TC# 2.A.59). This MFS family shows greatest similarity with families 2.A.1.11 and 2.A.1.13, both which transport anionic speices, for example, oxalate, formate and pyruvate (TC# 2.A.1.11) and monocarboxylates (TC# 2.A.1.13).  It is 32% identical and 52% similar to ArsK (TC# 2.A.1.70.9) which is an arsenite/antimonite exporter (Shi et al. 2018).

ArsP of Cupriavidus metallidurans (Ralstonia metallidurans)


ArsK, exporter of arsenite, antimonite, trivalent roxarsone and methylarsenite (Shi et al. 2018). Expression of arsK is induced by arsenite [As(III)], antimonite [Sb(III)], trivalent roxarsone [Rox(III)], methylarsenite [MAs(III)] and arsenate [As(V)], and heterologous expression of ArsK in an arsenic-hypersensitive E. coli strain showed that ArsK is essential for resistance to As(III), Sb(III), Rox(III) and MAs(III) but not to As(V), dimethylarsenite [Dimethyl-As(III)] or Cd(II). ArsK reduces the cellular accumulation of As(III), Sb(III), Rox(III) and MAs(III) but not to As(V) or Dimethyl-As(III). An arsenic regulator gene arsR2 is cotranscribed with arsK, and ArsR2 interacts with the arsR2-arsK promoter region without metalloids but is derepressed by As(III), Sb(III), Rox(III) and MAs(III). Thus, ArsK is an arsenic efflux protein  and is regulated by ArsR2 (Shi et al. 2018).


ArsK of Rhizobium radiobacter (Agrobacterium tumefaciens; Agrobacterium radiobacter)


2.A.1.71 The Valanimycin-resistance (Val-R) Family


TC#NameOrganismal TypeExample

The Valanimycin-resistance determinant, VlmF (probably a valanimycin:H  antiporter (Ma et al., 2000))


VlmF of Streptomyces viridifaciens (Q9LA76)


The UMF19a porter


UMF19a porter of Streptomyces coelicolor (Q93J85)


MFS transporter of 375 aas and 11 TMSs

UP of Patulibacter americanus


2.A.1.72 The Uncharacterized Major Facilitator-20 (UMF20) Family

These proteins are probable MDR exporters.


TC#NameOrganismal TypeExample

The UMF20A porter


UMF20A of Streptomyces coelicolor (Q9RL01)


MFS_1 of 429 aas

MFS_1 of Propionimicrobium lymphophilum


MFS_1 of 390 aas

MFS_1 of Mesorhizobium loti


2.A.1.73 The Unidentified Major Facilitator-21 (UMF21) Family

Most similar to TC# 2.A.1.80.


TC#NameOrganismal TypeExample

The UMF21A porter


UMF21A porter of Streptomyces coelicolor (Q9L102)


MFS permease of 397 aas

MFS permease of Actinoplanes friuliensis


MFS_1, MilK of 442 aas.

MilK of Streptomyces rimofaciens


2.A.1.74 The Uncharacterized Major Facilitator-22 (UMF22) Family

Family members may be MDR pumps.


TC#NameOrganismal TypeExample

UMF22a porter 


UMF22 porter of Streptomyces coelicolor (Q9S243)


MFS_1 of 408 aas

MFS_1 of Bacillus marmarensis


MFS_1 of 389 aas

MFS_1 of Variovorax paradoxus


MFS_1 of 401 aas

MFS_1 of Marinobacter santoriniensis


2.A.1.75 The Uncharacterized Major Facilitator-23 (UMF23) Family

Most closely related to TC# 2.A.1.11, mono- and di-carboxylate transporters


TC#NameOrganismal TypeExample

Probable transporter MCH1.  Although the name, "monocarboxylate transporter homologue 1" implies that this system transports monocarboxylates such as lactate, pyruvate and acetate, no evidence for this possibility was obtained (Makuc et al. 2001). Instead, the mch1-5 mutant strain, lacking all 5 such paralogues in yeast showed strongly reduced biomass yields in aerobic glucose-limited chemostat cultures, pointing to the involvement of Mch transporters in mitochondrial metabolism. Indeed, intracellular localization studies indicated that at least some of the Mch proteins reside in intracellular membranes.Thus, the yeast monocarboxylate transporter-homologs perform other functions other than do their mammalian counterparts (Makuc et al. 2001). Possibly they function in intracellular, organellar transport of these acids.


MCH1 of Saccharomyces cerevisiae



Mct of Coccidioides posadasii (E9CYW5)


Uncharacterized major facilitator, UMF23C


UMF23C of Candida albicans


Uncharacterized major facilitator UMF23D


UMF23D of Naegleria gruberi


UMF23 permease of 572 aa


UMF23 of Arabidopsis thaliana


Uncharacterized protein of 591 aas and 12 TMSs

UP of Chlamydomonas reinhardtii (Chlamydomonas smithii)


Uncharacterized MFS permease of 530 aas and 12 TMSs.

UP of Entamoeba histolytica


PICLORAM RESISTANT30 (PIC30) protein of 601 aas and 12 or 14 TMSs. It is a plasma membrane anion uptake porter, transporting picloram and other picolinate herbicides as well as nitrate, chlorate and chloride anions (Kathare et al. 2019). 

PIC30 of Arabidopsis thaliana


2.A.1.76 The Uncharacterized Major Facilitator-24 (UMF24) Family

Most similar to 2.A.1.15, aromatic acid porters.


TC#NameOrganismal TypeExample

Uncharacterized protein Mhp246


Mhp246 of Mycoplasma hyopneumoniae


Uncharacterized Mycoplama MFS carrier, UMF24B


UMF24B of Mycoplasma capricolum


Uncharacterized MFS carrier, UMF24C


UMF24C of Lactobacillus salivarius


MFS carrier of 525 aas and 12 TMSs.

MFS porter of Mycoplasma galisepticum


2.A.1.77 The Uncharacterized Major Facilitator-25 (UMF25) Family

Most closely related to TC# 2.A.1.15, transporters for organic carboxylates.


TC#NameOrganismal TypeExample

Unknown Major Facilitator UMF25a


UMF25a of Rhodopirellula baltica


Unknown Major Facilitator, UMF25b


UMF25b of Planctomyces limnophilus


2.A.1.78 The Uncharacterized Major Facilitator-26 (UMF26) Family

These transporters may be drug porters.


TC#NameOrganismal TypeExample

UMF26a of 416 aas and 12 TMSs.  Encoded by a gene that is adjacent to two ATP hydrolyzing subunits homologous to ABC proteins of the peptide transporters of TC family 3.A.1.5.


UMF26a of Parachlamydia acanthaemoebae (F8KXQ8)


UMF26b of 419 aas and 12 TMSs


UMF26b of Simkania negevensis (F8L9E4)


UMF26c of 457 aas and 12 TMSs


UMF26c of Phycisphaera mikurensis (I0II84)


UMF26d of 413 aas and 12 TMSs


UMF26d of Verrucomicrobiae bacterium (B5JEI3)


2.A.1.79 The Uncharacterized Major Facilitator-27 (UMF27) Family

Most similar to TC#2.A.1.11 (carboxylate transporters) and 2.A.1.55 (MDR pumps).


TC#NameOrganismal TypeExample

MFS permease of 485 aas


MFS permease of Cyanidioschyzon merolae


Uncharacterized MFS proter of 724 aas and 12 TMSs with a C-terminal hydrophilic extension.

UP of Chondrus crispus (Carrageen Irish moss) (Polymorpha crispa)


2.A.1.8 The Nitrate/Nitrite Porter (NNP) family


TC#NameOrganismal TypeExample

Nitrate/H+ symporter (K1);Nitrate/nitrite antiporter (K2).  The 3-d structure is available revealing a positively charged pathway for nitrate/nitrite lined with arginine residues with no apparent proton pathway suggesting exchange transport is the primary or sole mechanism.  The pathway is between the two halves of the protein and a rocker switch mechanism was proposed (Zheng et al. 2013).  In an in vitro reconstituted system, NarK appeared to be a nitrate/nitrite antiporter.  High-resolution crystal structures in the nitrate-bound occluded, nitrate-bound inward-open and apo inward-open states have been solved (Fukuda et al. 2015).


NarK (NarK1-K2) of E. coli


NO3-/NO2- transporter (NO3- uptake permease; NO2- exporter) (probable NO3-/NO2- antiporter) (stress-induced; Clegg et al., 2006; Jia et al. 2009)


NarU of E. coli


The 24 TMS, 2 domain, NarK1-NarK2 porter (NarK1 = a NO3-/H+ symporter; NarK2 = a NO3-/NO2- antiporter).  NarK1 is a nitrate/proton symporter with high affinity for nitrate while NarK2 is a nitrate/nitrite antiporter with lower affinity for nitrate (Goddard et al., 2008).  Each transporter requires two conserved arginine residues for activity.  A transporter consisting of inactivated NarK1 fused to active NarK2 has a dramatically increased affinity for nitrate compared with NarK2 alone, implying a functional interaction between the two domains (Goddard et al., 2008).


NarK1/NarK2 of Roseobacter denitrificans (Q166T6)


The root cortical and epidermal cell, high affinity, plasma membrane, NO3- uptake transporter, NRT2.1 (Wirth et al., 2007). Also functions in nitrate sensing and signaling (Miller et al., 2007; Girin et al., 2010). Activity only occurs when NRT2.1 is complexed with NAR2.1 (WR3; 8.A.20.1.1) in a 2:2 tetrameric complex (Yong et al., 2010). NAR2.1 has an N-terminal and a C-terminal TMS and has been annotated as a calcineurin-like phosphoesterase family member (Yong et al., 2010).  Ntr transporters may also play a role in gaseous NO2 uptake by leaves (Hu et al. 2014).  The Medicago truncatula orthologue has been characterized (Pellizzaro et al. 2014). An NRT2 homologue in wheat has been identifed and partially characterized (Kumar et al. 2022). Nitrate is the main form of inorganic nitrogen that crops absorb, and nitrate transporters 2 (NRT2) are high affinity nitrate uptake porters. When the available nitrate is limiting, the high affinity transport systems are activated. Most NRT2s cannot transport nitrates alone and require the assistance of helper proteins belonging to nitrate assimilation related family (NAR2; TC# 8.A.20.1.1) to complete the transport of nitrate (Zhao et al. 2023). Crop nitrogen utilization efficiency is affected by environmental conditions, and there are differences between different plant varieties.  Sorghum bicolor has high stress tolerance and is efficient in soil nitrogen utilization. The S. bicolor genome database was scanned for gene structures, chromosomal localizations, physicochemical properties, secondary structures and transmembrane domains, signal peptides and subcellular localizations, promoter region cis-acting elements, phylogenetic evolution, SNP recognition and annotation, and selection pressure of gene family members (Zhao et al. 2023). Through bioinformatics analysis, 5 NRT2 gene members (designated as SbNRT2-1a, SbNRT2-1b, SbNRT2-2, SbNRT2-3, and SbNRT2-4) and 2 NAR2 gene members (designated SbNRT3-1 and SbNRT3-2) were identified, the number of which was less than that of foxtail millet. SbNRT2/3 could be divided into four subfamilies. All were present in the plasma membrane; SbNRT2 proteins lacked signal peptides, but SbNRT3 proteins contained them. Expression was responsive to plant hormones and stress response elements (Zhao et al. 2023).


NRT2.1 of Arabidopsis thaliana (O82811)


High affinity nitrate/nitrite antiporter and uptake porter, NrtB (Unkles et al., 1991; 2011; Wang et al. 2008).


NrtB of Emericella (Aspergillus) nidulans (Q8X193)


Nitrate/nitrite uptake porter, NapA (Wang et al., 2000)


NapA of Trichodesmium sp. WH 9601 (Q9RA38)


Probable nitrate transporter NarT


NarT of Staphylococcus carnosus


MFS porter of 430 aas


MFS porter of Rhizobium loti


Nitrate/nitrite transporter, NarK2, of 468 aas and 12 TMSs. The narK1 and narK2 genes are located in an operon, narK1K2GHJI, with the structural genes for the nitrate reductase complex.  Utilizing an isogenic narK1 mutant, a narK2 mutant, and a narK1K2 double mutant, Sharma et al. 2006 explored the effect on growth under denitrifying conditions. While the ΔnarK1::Gm mutant was only slightly affected, but both the ΔnarK2::Gm and double mutants exhibited poor nitrate-dependent, anaerobic growth although all three strains had wild-type levels of nitrate reductase activity. Nitrate uptake measurements showed that NarK2 has most of the activity.  E. coli narK rescued both mutants.

NarK2 of Pseudomonas aeruginosa


NRT2.1 high affinity Na+-dependent nitrate uptake porter of 517 aas and 12 TMSs. It functions with the aoxillary protein, NAR2 (TC# 8.A.20.1.2) (Rubio et al. 2019). Functional characterization of the GhNRT2.1e gene revealed its role in improving nitrogen use efficiency in Gossypium hirsutum (Zhang et al. 2023).

NTR2.1 of Zostera marina


Nitrate uptake porter


NasA of Bacillus subtilis


Nitrate/nitrite uptake porter


NrtP of Synechococcus PCC7002


Nitrate transporter


Nitrate porter of Cylindrotheca fusiformis


Nitrate/nitrite transporter/antiporter, CrnA/NrtA (Unkles et al., 1991; Beckham et al. 2010). The nitrate signature sequences (NS1 and NS2) in TMSs 5 and 11 and arg residues in TMSs 2 and 8 may influence substrate binding (Unkles et al., 2012).


CrnA of Emericella nidulans


Nitrate transporter


Nitrate porter of Chlamydomonas reinhardtii


High affinity Nitrate/nitrite uptake transporter, Nar4.


Nar4 of Chlamydomonas reinhardtii (A8J4P3) 


NO2- extrusion, NO3-/NO2- exchange permease, NarK1


NarK1 of Thermus thermophilus HB8


NO2- extrusion, NO3-/NO2- exchange permease, NarK2


NarK2 of Thermus thermophilus HB8


2.A.1.80 The Uncharacterized Major Facilitator-28 (UMF28) Family

Most similar to TC# 2.A.1.73.


TC#NameOrganismal TypeExample

Uncharacterized MFS permease of 515 aas


Putative peremease of Galdieria sulphuraria


MFS_1 of 395 aas

MFS1 of Plesiocystis pacifica


MFS_1 of 398 aas.

MFS_1 of Desulfobulbus propionicus


MFS transporter of 410 aas.

MFS1 of Octadecabacter antarcticus


MFS_1 of 401 aas

MFS_1 of Crocosphaera watsonii


2.A.1.81 The Copper Uptake Porter (Cu-UP)

Most similar to TC# 2.A.1.2, MDR pumps.


TC#NameOrganismal TypeExample

The copper (Cu2+) uptake porter, CcoA of 405 aas and 12 TMSs. CcoA-mediated Cu2+ import relies on conserved Met and His residues that could act as metal ligands at the membrane-embedded Cu2+-binding domain (Khalfaoui-Hassani et al. 2016). It provides cytoplasmic Cu needed for cbb3-type cytochrome c oxidase (cbb3-Cox) biogenesis (Khalfaoui-Hassani et al. 2021). Residues important for and/or esstential for function have been identified. CcoA undergoes a thiol:disulfide oxidoreduction cycle, which is important for its Cu import activity (Khalfaoui-Hassani et al. 2021).


CcoA of Rhodobacter capsulatus


Putative copper uptake porter, MFS_1 of 420 aas


MFS_1 of Chloroflexus aggregans


MFS permease of 403 aas.


MFSA permease of Corynebacterium glutamicum


MFS porter of 350 aas

Thaumarchaeota (Archaea)

MFS porter of Candidatus Caldiarchaeum subterraneum


Riboflavin uptake transporter of 398 aas and 12 TMSs, RfnT (Gutiérrez-Preciado et al. 2015).

RfnT of Ochrobactrum anthropi


2.A.1.82 The Plant Copper Uptake Porter (Pl-Cu-UP)

Shows very substantial similarity with TC#s 2.A.1.15 (specific for aromatic acids), 2.A.1.19 (specific for organic cations) and 2.A.1.22 (specific for neurotransmitters).


TC#NameOrganismal TypeExample

The barley copper uptake porter, CT-1 of 749 aas; nearly identical to the wheat orthologue (Li et al. 2013).


CT-1 of Hordeum vulgare (F2CRE4)


The putative copper uptake porter, CT1, of 825 aas. The C-terminal domain of 300 aas is a DUF572 (COG5134) domain.


CT1 of Ostreococcus tauri (Q010B9)


Synaptic vesicle 2-related protein (SV2-related protein), SVOP or SLC22B4.  This protein localizes to neurotransmitter-containing vesicles and has a nucleotide binding site (Yao and Bajjalieh 2009). ATP, GTP, TTP, CTP and NAD biind, with the highest affinity for NAD, in contrast to SV2 (TC# 2.A.1.22.1), which binds both NAD and ATP with equal affinity. May transport nicotinate.


Sv2p of Mus musculus


Niacin uptake porter NiaP (Jeanguenin et al. 2012)


YceI of Bacillus subtilis (O34691)


Uncharacterized MFS protein of 460 aas


UP of Volvox carteri (Green alga)


Synaptic vesicle 2-related protein, SVOPL, of 492 aas and 12 TMSs in a 6 + 1 + 5 TMS arrangement.  Gene disruption gives rise to neurocognitive disabilities (Nilsson et al. 2017), and mutations can give rise to retinal dystrophies, hereditary blinding disorders (Patel et al. 2018).  SVOPL is also a potential cell survival gene that undergoes allelic switching (Boot et al. 2019).

SVOPL of Homo sapiens


2.A.1.83 The 1-arseno-3-phosphoglycerate exporter (APGE) Family


TC#NameOrganismal TypeExample

MFS porter; 1-arseno-3-phosphoglycerate (1As3PGA) exporter, ArsJ.  Encoded in an operon concerned with arsenic resistance, encoding the enzymes and transporters of a new pathway of arsenic biotransformation.  The adjacent gene encodes a 3-phosphoglycerate dehydrogenase homologue that probably forms the substrate of this MFS porter which could be expelled from the cell (Chen et al. 2016).


ArsJ of Aliivibrio (Vibrio) salmonicida


Putative 1-arseno-3-phosphoglycerate exporter, MFS-83.


MFS-83 of Ferrimonas balearica


Putative 1-arseno-3-phosphoglycerate exporter of 460 aas (see 2.A.1.83.1).


MFS-83 of Ectocarpus siliculosus (Brown alga


2.A.1.84 The 1-arseno-3-phosphoglycerate exporter (APGE) Family

This family shows greatest sequence similarity with TC# 2.A.1.2 and 2.A.1.24, MDR export porters.


TC#NameOrganismal TypeExample

Putative MFS permease of 467 aas and 12 TMSs


MFS permease of Treponema denticola


Uncharacterized protein of 435 aas and 12 TMSs.


UP of Slackia heliotrinireducens (Peptococcus heliotrinreducens)


Uncharacterized protein


UP of Streptosporangium roseum


2.A.1.85 The Uncharacterized Major Facilitator-29 (UMF29) Family

The members of this family are not closely related to any other MFS family.


TC#NameOrganismal TypeExample

Uncharacterized protein of 541 aas and 12 TMSs

UP of Isoptericola variabilis


Putative 12 TMS permease of 534 aas, HalU (Besse et al. 2015).

HalU of Halalkalicoccus jeotgali


Putative MFS permease

MFS permease of Actinoplanes friuliensis


Putative permease of 510 aas

PP of Halobacterium salinarum (Halobacterium halobium)


Putative transport protein of 525 aas and 14 TMSs in a 2 + 8 + 2 + 3 TMS arrangement. It is homologous to other proteins annotated as ABC, transporter and hypothetical proteins.

PT of Subtercola boreus


PAM68 family protein of 524 aas and 14 TMSs in a 2 +4 + 2 + 2 + 2 TMS arrangement. 

PAM68 protein of Cryobacterium sp.


2.A.1.86 The Uncharacterized Major Facilitator-30 (UMF30) Family


TC#NameOrganismal TypeExample

MFS uptake permease.  The gene is adjacent to a putative SAM-dependent methyl transferase, one homologue of which is a puromycin methyl transferase.  Perhaps the transport substrate is a drug that is modified by methylation for detoxification purposes. This family is most closely, but distantly related to the AAHS family (2.A.1.15).


MFS uptake permease of Myxococcus xanthus


Fused protein with N-terminal transmembrane region of 7 putative TMSs and a C-terminal hydrophilic domain homologous to SAM-dependent spermidine synthase.  The N-terminus of this protein shows extensive sequence similarity with 2.A.1.86.1 but shows weak similarity with other MFS permeases.


Fused protein of Thiocapsa marina


Uncharacterized protein of 512 aas and 7 TMSs.

UP of Candidatus Thiodiazotropha endoloripes


Uncharacterized putative S-adenosyl-L-methionine-dependent methyltransferase with a 7 TMS N-terminus (Pegg and Michael 2010).

UP of Magnetospirillum gryphiswaldense


Polyamine aminopropyltransferase or spermidine synthase of 516 aas and 7 N-terminal TMSs.

SpeE of Comamonas testosteroni


Putative MFS transporter, SVOPL or SLC22B5 (in humans), of 706 aas and 13 TMSs with two repeats of 6 TMSs with the 13th TMS being the extra one.

MFS porter of Candidatus Entotheonella palauensis


Uncharacterized protein of 212 aas and 6 TMSs.

UP of Legionella maceachernii (Tatlockia maceachernii)


Uncharacterized protein of 688 aas and 14 TMSs in a 7 TMS + large hydrophilic domain + 7 more TMSs.

UP of Desulfosarcina alkanivorans


2.A.1.87 The Uncharacterized Major Facilitator-31 (UMF31) Family


TC#NameOrganismal TypeExample

Uncharacterized protein of 435 aas and 12 TMSs in a 6 + 6 arrangement. It most resembles 2.A.1.3.53, an azole resistance protein.  Therefore, this protein might be a drug exporter.

UP of Gardnerella vaginalis


Uncharacterized MFS protein of 431 aas and 12 TMSs.

UP of Arcanobacterium haemolyticum


Uncharacterized MFS protein of 423 aas and 12 TMSs.

UP of Kushneria konosiri


2.A.1.88 The Uncharacterized Major Facilitator-32 (UMF32) Family


TC#NameOrganismal TypeExample

Uncharacterized protein of 434 aas and 12 TMSs.

UP of Lokiarchaeum sp.


Uncharacterized protein of 430 aas and 12 TMSs.

UP of Lokiarchaeum sp.


2.A.1.89 The Uncharacterized Major Facilitator-33 (UMF33) Family


TC#NameOrganismal TypeExample

UP of 535 aas and 11 TMSs

UP of Candidatus Lokiarchaeota archaeon CR_4


Uncharacteerized protein of 563 aas and 12 TMSs in a 6 + 6 TMS arrangement. 

UP of Candidatus Lokiarchaeota archaeon CR_4


2.A.1.9 The Phosphate: H+ Symporter (PHS) Family


TC#NameOrganismal TypeExample

High affinity Pi uptake porter, SUL1, Sul-1, SFP2 of 859 aas and 10 TMSs. (also functions in Mn2+ homeostasis); may transport a phosphate·Mn2+ complex (Jensen et al., 2003). Also takes up selenite (Lazard et al., 2010).  May be a "transceptor", combining transport and receptor functions (Diallinas 2017).



Pho84 of Saccharomyces cerevisiae (P25297)


High affinity (25 mμM) phosphate uptake porter, PiPT (Yadav et al. 2010).  The high resolution structure has been determined by x-ray crystallography (Pedersen et al. 2013).


PiPT of Piriformospora indica


Phosphate transporter, PT, of 543 aas and 12 TMSs. It has a micormolar Km for phosphate uptake, is found in the plasma membrane and is induced by low medium phosphate concentrations (Wang et al. 2014).


PT in the ectomycorrhizal fungus, Boletus edulis


Phosphate transporter and receptor (transceptor) of 543 aas and 12 TMSs.  Important for signalling and uptake of phosphate.  The majority of terrestrial vascular plants can form mutualistic associations with obligate biotrophic arbuscular mycorrhizal (AM) fungi from the phylum Glomeromycota. This mutualistic symbiosis provides carbohydrates to the fungus, and reciprocally improves plant phosphate uptake. AM fungal transporters can acquire phosphate from the soil through the hyphal networks. Xie et al. 2016 reported a high-affinity phosphate transporter GigmPT that is required for AM symbiosis. GigmPT functions as a phosphate transceptor for the activation of the phosphate signaling pathway as well as the protein kinase A signaling cascade.

PT of Gigaspora margarita