TCDB is operated by the Saier Lab Bioinformatics Group
TC-SUPERFAMILIES:

AAA-ATPase Superfamily

These ATPase are found as coomponents of several protein secretion systems as well as synaptosomal fusion systems. All of these systems are multi-component systems where the ATPases play energizing roles. See Miller JM, Enemark EJ., Fundamental Characteristics of AAA+ Protein Family Structure and Function. Archaea. 2016 PMID: 27703410.

1.F.1 - The Synaptosomal Vesicle Fusion Pore (SVF-Pore) Family
3.A.16 - The Endoplasmic Reticular Retrotranslocon (ER-RT) Family
3.A.20 - The Peroxisomal Protein Importer (PPI) Family
3.A.24 - The Type VII or ESX Protein Secretion System (T7SS) Family
3.A.25 - The Symbiont-specific ERAD-like Machinery (SELMA) Family
9.A.62 - The AAA-ATPase, Bcs1 (Bcs1) Family

ABC1, ABC2, ABC3 Superfamilies

as well as the ECF sub-superfamily are all included within the functional ABC superfamily, TC#3.A.1. Their descriptions and constituent families are presented in paragraphs 3 and 4 of the superfamily description under TC#3.A.1. The ABC2 uptake Superfamily includes proteins in TC families 2.A.87 (P-RFT) and 2.A.88 (VUT or ECF).

For efflux systems see: (Wang, B., M. Dukarevich, E.I. Sun, M.R. Yen, and M.H. Saier, Jr. (2009). Membrane porters of ATP-binding cassette transport systems are polyphyletic. J. Membr. Biol. 231: 1-10.) for more details.

For uptake systems see: (Zheng, W.H., A. Västermark, M.A. Shlykov, V. Reddy, E.I. Sun, and M.H. Saier, Jr. (2013). Evolutionary relationships of ATP-Binding Cassette (ABC) uptake porters. BMC Microbiol 13: 98.) for more details.

Adenylate/Guanylate Cyclase (A/GC) Family

These enzymes catalyzed the synthesis of cAMP or cGMP from ATP or GTP, respectively.

8.A.59 - The SLC and TCST-Associated Component (STAC-A) Family
8.A.85 - The Guanylate Cyclase (GC) Family
9.B.33 - The Sensor Histidine Kinase (SHK) Family

Aerolysin Superfamily

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

1.C.3 - The α-Hemolysin Channel-forming Toxin (αHL) Family
1.C.4 - The Aerolysin Channel-forming Toxin (Aerolysin) Family
1.C.5 - The Channel-forming ε-toxin (ε-toxin) Family
1.C.13 - The Channel-forming Leukocidin Cytotoxin (Ctx) Family
1.C.14 - The Cytohemolysin (CHL) Family
1.C.43 - The Earthworm Lysenin Toxin (Lysenin) Family
1.C.74 - The Snake Cytotoxin (SCT) Family

Anoctamin

The Anoctamin superfamily is found under TC# 1.A.17 and contains 7 families.

APC Superfamily

The APC superfamily consists of numerous families of porters that transport amino acids and their dereivatives. See: Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81.

Wong, F.H., J.S. Chen, V. Reddy, J.L. Day, M.A. Shlykov, S.T. Wakabayashi, and M.H. Saier, Jr. (2012). The amino acid-polyamine-organocation superfamily. J. Mol. Microbiol. Biotechnol. 22: 105-113. These proteins have two 5 TMS repeats except for NCS2, AE and SulP which have two 7 TMS repeats. See: Vastermark A, Wollwage S, Houle ME, Rio R and Saier MH Jr. (2014). Expansion of the APC superfamily of secondary carriers, Proteins. 82:2797-2811. PMID: 25043943. and Västermark Å and Saier MH Jr. (2014) Evolutionary relationship between 5+5 and 7+7 inverted repeat folds within the amino acid-polyamine-organocation superfamily. Proteins. 82:336-46. PMID: 24038584.

2.A.3 - The Amino Acid-Polyamine-Organocation (APC) Family
2.A.15 - The Betaine/Carnitine/Choline Transporter (BCCT) Family
2.A.18 - The Amino Acid/Auxin Permease (AAAP) Family
2.A.21 - The Solute:Sodium Symporter (SSS) Family
2.A.22 - The Neurotransmitter:Sodium Symporter (NSS) Family
2.A.25 - The Alanine or Glycine:Cation Symporter (AGCS) Family
2.A.26 - The Branched Chain Amino Acid:Cation Symporter (LIVCS) Family
2.A.30 - The Cation-Chloride Cotransporter (CCC) Family
2.A.31 - The Anion Exchanger (AE) Family
2.A.39 - The Nucleobase:Cation Symporter-1 (NCS1) Family
2.A.40 - The Nucleobase/Ascorbate Transporter (NAT) or Nucleobase:Cation Symporter-2 (NCS2) Family
2.A.42 - The Hydroxy/Aromatic Amino Acid Permease (HAAAP) Family
2.A.46 - The Benzoate:H+ Symporter (BenE) Family
2.A.53 - The Sulfate Permease (SulP) Family
2.A.55 - The Metal Ion (Mn2+-iron) Transporter (Nramp) Family
2.A.72 - The K+ Uptake Permease (KUP) Family
2.A.114 - The Putative Peptide Transporter Carbon Starvation CstA (CstA) Family
2.A.120 - The Putative Amino Acid Permease (PAAP) Family

ArsA ATPase (ArsA) Superfamily

Includes ATPases in the following TC families: 2.A.59 (2.A.59.1.5 and 2.A.59.1.6 only), 3.A.4, 3.A.19 and 3.A.21. Castillo, R. and M.H. Saier. (2010). Functional Promiscuity of Homologues of the Bacterial ArsA ATPases. Int J Microbiol 2010: 187373.

3.A.4 - The Arsenite-Antimonite (ArsAB) Efflux Family
3.A.19 - The TMS Recognition/Insertion Complex (TRC) Family
3.A.21 - The C-terminal Tail-Anchored Membrane Protein Biogenesis/ Insertion Complex (TAMP-B) Family

Bacterial Bacteriocin (BB) Superfamily

Hassan, M., M. Kjos, I.F. Nes, D.B. Diep, and F. Lotfipour. (2012). Natural antimicrobial peptides from bacteria: characteristics and potential applications to fight against antibiotic resistance. J Appl Microbiol 113: 723-736.

Nishie, M., J. Nagao, and K. Sonomoto. (2012). Antibacterial peptides (bacteriocins): an overview of their diverse characteristics and applications. Biocontrol Sci 17: 1-16.

1.C.22 - The Lactococcin A (Lactococcin A) Family
1.C.24 - The Pediocin (Pediocin) Family
1.C.26 - The Lactacin X (Lactacin X) Family
1.C.27 - The Divergicin A (Divergicin A) Family
1.C.29 - The Plantaricin EF (Plantaricin EF) Family
1.C.30 - The Plantaricin JK (Plantaricin JK) Family
1.C.31 - The Channel-forming Colicin V (Colicin V) Family
1.C.53 - The Lactocyclicin Q (Lactocyclicin Q) Family
1.C.102 - The Cerein (Cerein) Family

BART Superfamily

Mansour, N.M., Sawhney, M., Tamang, D.G., Vogl, C., Saier, M.H. Jr. 2007. The bile/arsenite/riboflavin transporter (BART) superfamily. FEBS Journal 274(3):612-29.

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

2.A.10 - The 2-Keto-3-Deoxygluconate Transporter (KdgT) Family
2.A.28 - The Bile Acid:Na+ Symporter (BASS) Family
2.A.59 - The Arsenical Resistance-3 (ACR3) Family
2.A.69 - The Auxin Efflux Carrier (AEC) Family
2.A.87 - The Prokaryotic Riboflavin Transporter (P-RFT) Family
9.B.34 - The Kinase/Phosphatase/Cyclic-GMP Synthase/Cyclic di-GMP Hydrolase (KPSH) Family

Bcl-2

The Bcl-2 Superfamily includes two families in TCDB, the Bcl-2 family (TC# 1.A.21), consisting of homologues, some of which form transmembrane pores, and the Bim Family (8.A.69), members of which influence apoptosis, either positively or negatively, and interact with TOM complex proteins (TC# 3.A.8).

1.A.21 - The Bcl-2 (Bcl-2) Family
8.A.69 - The Pro-apoptotic Bcl-2-Family Protein Bim (Bim) Family

CAAX Superfamily

The CAAX Superfamily has been described: PMID: 21570408

9.B.1 - The Integral Membrane CAAX Protease (CAAX Protease) Family
9.B.2 - The Integral Membrane CAAX Protease-2 (CAAX Protease2) Family
9.B.47 - The γ-Secretase (γ-Secretase) Family
9.B.217 - The Transmembrane PrsW Protease (PrsW) Family
9.B.218 - The DUF2324 Family of Putative Integral Membrane Metaloproteases (IMMP) Family
9.B.219 - The CPBP Intramembrane Metalloprotease (CPBP) Family
9.B.220 - The CAAX Protease Self-Immunity (CAAX-PSI) Family

Cation Diffusion Facilitator (CDF) Superfamily

Paulsen, I.T. and M.H. Saier, Jr. (1997). A novel family of ubiquitous heavy metal ion transport proteins. J. Membr. Biol. 156: 99-103.

Matias, M.G., K.M. Gomolplitinant, D.G. Tamang, and M.H. Saier, Jr. (2010). Animal Ca2+ release-activated Ca2+ (CRAC) channels appear to be homologous to and derived from the ubiquitous cation diffusion facilitators. BMC Res Notes 3: 158.

1.A.52 - The Ca2+ Release-activated Ca2+ (CRAC) Channel (CRAC-C) Family
2.A.4 - The Cation Diffusion Facilitator (CDF) Family
2.A.19 - The Ca2+:Cation Antiporter (CaCA) Family
2.A.103 - The Bacterial Murein Precursor Exporter (MPE) Family

Cecropin Superfamily

Tamang, D.G. and M.H. Saier, Jr. (2006). The cecropin superfamily of toxic peptides. J. Mol. Microbiol. Biotechnol. 11: 94-103.

1.C.17 - The Cecropin (Cecropin) Family
1.C.18 - The Melittin (Melittin) Family
1.C.32 - The Amphipathic Peptide Mastoparan (Mastoparan) Family
1.C.51 - The Pilosulin (Pilosulin) Family
1.C.52 - The Dermaseptin (Dermaseptin) Family
1.C.62 - The Pseudopleuronectes americanus (flounder) Pleurocidin (Pleurocidin) Family
1.C.76 - The Pore-forming Maculatin Peptide (Maculatin) Family
1.C.124 - The Antimicrobial Pore-forming Pandinin (Pin) Family

Circular Bacterial Bacteriocin (CBB) Superfamily

*1.C.53 is also shared with the BB Superfamily (see BB Superfamily list). Maqueda, M., M. Sánchez-Hidalgo, M. Fernández, M. Montalbán-López, E. Valdivia, and M. Martínez-Bueno. (2008). Genetic features of circular bacteriocins produced by Gram-positive bacteria. FEMS Microbiol. Rev. 32: 2-22.

1.C.28 - The Bacteriocin AS-48 Cyclic Polypeptide (Bacteriocin AS-48) Family
1.C.83 - The Gassericin (Gassericin) Family
1.C.84 - The Subtilosin (Subtilosin) Family
1.C.90 - The Carnocyclin A (Carnocyclin) Family

Copper Resistance Superfamily

9.A.55 - The TMEM205 (TMEM205) Family
9.B.62 - The Copper Resistance (CopD) Family

CPA Superfamily

Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81.

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

2.A.37 - The Monovalent Cation:Proton Antiporter-2 (CPA2) Family
2.A.70 - The Malonate:Na+ Symporter (MSS) Family
2.A.98 - The Putative Sulfate Exporter (PSE) Family
3.B.1 - The Na+-transporting Carboxylic Acid Decarboxylase (NaT-DC) Family

Cytochrome b561 (Cytb561) superfamily

The cytochrome b561 domain appears to be present in at least two family and therefore comprises a superfamily.

5.B.2 - The Eukaryotic Cytochrome b561 (Cytb561) Family
9.B.57 - The Conidiation and Conidial Germination Protein (CCGP) Family

Defensin Superfamily

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

1.C.19 - The Defensin (Defensin) Family
1.C.45 - The Plant Defensin (Plant Defensin) Family
1.C.47 - The Insect/Fungal Defensin (Insect/Fungal Defensin) Family
1.C.85 - The Pore-Forming β-Defensin (β-Defensin) Family
8.B.1 - The Long (4C-C) Scorpion Toxin (L-ST) Superfamily
8.B.2 - The Short Scorpion Toxin (S-ST) Superfamily

Drug/Metabolite Transporter (DMT) Superfamily

2.A.7 (32 families)

Jack, D.L., N.M. Yang, and M.H. Saier, Jr. (2001). The drug/metabolite transporter superfamily. Eur J Biochem 268: 3620-3639.

Yen, M.R., J.S. Chen, J.L. Marquez, E.I. Sun, and M.H. Saier. (2010). Multidrug resistance: phylogenetic characterization of superfamilies of secondary carriers that include drug exporters. Methods Mol Biol 637: 47-64.

2.A.7 - The Drug/Metabolite Transporter (DMT) Superfamily

ENaC/P2X Superfamily

1.A.6 (ENaC) and 1.A.7 (P2X receptor) have similar 3-d structures and are likely to be homologous (Kawate et al, 2009; Gonzales et al, 2009)

Le, T. and M.H. Saier, Jr. (1997). Phylogenetic characterization of the epithelial Na+ channel (ENaC) family. Mol. Membr. Biol. 13: 149-157.

Gonzales, E.B., T. Kawate, and E. Gouaux. (2009). Pore architecture and ion sites in acid-sensing ion channels and P2X receptors. Nature 460: 599-604.

Kawate, T., J.C. Michel, W.T. Birdsong, and E. Gouaux. (2009). Crystal structure of the ATP-gated P2X(4) ion channel in the closed state. Nature 460: 592-598.

1.A.6 - The Epithelial Na+ Channel (ENaC) Family
1.A.7 - The ATP-gated P2X Receptor Cation Channel (P2X Receptor) Family

Endomembrane Protein-Translocon (EMPT) Superfamily

Bolte, K., N. Gruenheit, G. Felsner, M.S. Sommer, U.G. Maier, and F. Hempel. (2011). Making new out of old: recycling and modification of an ancient protein translocation system during eukaryotic evolution. Mechanistic comparison and phylogenetic analysis of ERAD, SELMA and the peroxisomal importomer. Bioessays 33: 368-376.

Glycosyl Transferase/Transporter (GTT) Superfamily

Glycosyl transferases can be integral membrane proteins with numerous TMSs that in some cases have been shown to transport the growing polysaccharide chain as it is being elongated in a group translocation process.

4.D.1 - The Putative Vectorial Glycosyl Polymerization (VGP) Family
4.D.2 - The Glycosyl Transferase 2 (GT2) Family
4.D.3 - The Glycan Glucosyl Transferase (OpgH) Family

Guided Entry of Tail-anchored Protein (GET) Superfamily

In Eukaryotes, tail-anchored proteins use a distinctive pathway for insertion. Animal systems are in TC# 3.A.19 while Fungal systems are in TC#3.A.21.

Heme-binding YedZ (YedZ) Superfamily

YedZ is a heme-binding protein domain found in many proteins in various families in TCDB. Members of the YedZ family (TC# 9.B.7) often contain only a YedZ domain, but an MFS putative iron transporter (TC# 2.A.1.43.2), a bacterial ferric reductase (TC# 5.A.1.6.4), a human ferric reductase (TC# 5.B.6.1.1), a sulfoxide reductase (TC# 5.B.7.1.1, and a putative sulfite oxidase (TC# 5.B.7.2.1) all contain YedZ domains, usually as a C-terminal domain. 6 TMS YedZ domains arose by triplication of a 2 TMS precursor peptide (T.von Rozycki et al., 2004,The YedZ Family, JMMB, 8, 129-140).

5.B.7 - The YedZ (YedZ) Family

Holin Superfamily I

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.11 - The φ11 Holin (φ11 Holin) Family

Holin Superfamily II

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.1 - The P21 Holin S (P21 Holin) Family
1.E.6 - The T7 Holin (T7 Holin) Family
1.E.7 - The HP1 Holin (HP1 Holin) Family
1.E.25 - The Pseudomonas phage F116 Holin (F116 Holin) Family
1.E.50 - The Beta-Proteobacterial Holin (BP-Hol) Family

Holin Superfamily III

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.2 - The λ Holin S (λ Holin) Family
1.E.3 - The P2 Holin (P2 Holin) Family
1.E.4 - The LydA Holin (LydA Holin) Family
1.E.5 - The PRD1 Phage P35 Holin (P35 Holin) Family
1.E.20 - The Pseudomonas aeruginosa Hol Holin (Hol Holin) Family
1.E.34 - The Putative Actinobacterial Holin-X (Hol-X) Family
1.E.41 - The Deinococcus/Thermus Holin (D/T-Hol) Family

Holin Superfamily IV

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.10 - The Bacillus subtilis φ29 Holin (φ29 Holin) Family
1.E.16 - The Cph1 Holin (Cph1 Holin) Family
1.E.19 - The Clostridium difficile TcdE Holin (TcdE Holin) Family
1.E.40 - The Mycobacterial 4 TMS Phage Holin (MP4 Holin) Family

Holin Superfamily V

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.21 - The Listeria Phage A118 Holin (Hol118) Family
1.E.29 - The Holin Hol44 (Hol44) Family

Holin Superfamily VI

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.12 - The φAdh Holin (φAdh Holin) Family
1.E.26 - The Holin LLH (Holin LLH) Family

Holin Superfamily VII

Reddy, B.L. and M.H. Saier, Jr. (2013). Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim. Biophys. Acta. 1828: 2654-2671.

1.E.36 - The Mycobacterial 2 TMS Phage Holin (M2 Hol) Family

Huwentoxin Superfamily

Diao, J., Lin, Y., Tang, J., and Liang, S. (2003). cDNA sequence analysis of seven peptide toxins from the spider Selenocosmia huwena. Toxicon 42: 715-723.

8.B.3 - The Huwentoxin-1 (Huwentoxin-1) Family
8.B.4 - The Conotoxin T (Conotoxin) Family
8.B.5 - The Na+/K+/Ca2+ Channel Targeting Tarantula Huwentoxin (THT) Family
8.B.6 - The Ca2+ Channel-targeting Spider Toxin (CST) Family
8.B.12 - The Spider Toxin (STx2) Family
8.B.16 - The Maurocalcine Family
8.B.19 - The Sea Anemone K+ Channel Blocker Toxin, BcsTx3 (BcsTx3) Family
8.B.21 - The Spider Insecticidal Neurotoxin Cyrtautoxin (Cyrautoxin) Family

IT Superfamily

Prakash S, Cooper G, Singhi S, Saier MH. The ion transporter superfamily. Biochim Biophys Acta. 2003 Dec 3;1618(1):79-92.

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

2.A.8 - The Gluconate:H+ Symporter (GntP) Family
2.A.11 - The Citrate-Mg2+:H+ (CitM) Citrate-Ca2+:H+ (CitH) Symporter (CitMHS) Family
2.A.13 - The C4-Dicarboxylate Uptake (Dcu) Family
2.A.14 - The Lactate Permease (LctP) Family
2.A.34 - The NhaB Na+:H+ Antiporter (NhaB) Family
2.A.35 - The NhaC Na+:H+ Antiporter (NhaC) Family
2.A.45 - The Arsenite-Antimonite (ArsB) Efflux Family
2.A.47 - The Divalent Anion:Na+ Symporter (DASS) Family
2.A.61 - The C4-dicarboxylate Uptake C (DcuC) Family
2.A.62 - The NhaD Na+:H+ Antiporter (NhaD) Family
2.A.68 - The p-Aminobenzoyl-glutamate Transporter (AbgT) Family
2.A.94 - The Phosphate Permease (Pho1) Family
2.A.101 - The Malonate Uptake (MatC) Family (Formerly UIT1)
2.A.111 - The Na+/H+ Antiporter-E (NhaE) Family
2.A.118 - The Basic Amino Acid Antiporter (ArcD) Family

LysE Superfamily

Tsu, Brian V.; Saier, Milton H. (2015). The LysE Superfamily of Transport Proteins Involved in Cell Physiology and Pathogenesis. PloS One 10 (10). doi:10.1371/journal.pone.0137184. ISSN 1932-6203. PMC 4608589. PMID 26474485. Vrljic M, Garg J, Bellmann A, Wachi S, Freudl R, Malecki MJ, Sahm H, Kozina VJ, Eggeling L, Saier MH Jr (1999). The LysE superfamily: topology of the lysine exporter LysE of Corynebacterium glutamicum, a paradyme for a novel superfamily of transmembrane solute translocators. J Mol Microbiol Biotechnol. 1999;1:327-36.

2.A.75 - The L-Lysine Exporter (LysE) Family
2.A.76 - The Resistance to Homoserine/Threonine (RhtB) Family
2.A.77 - The Cadmium Resistance (CadD) Family
2.A.95 - The 6 TMS Neutral Amino Acid Transporter (NAAT) Family
2.A.106 - The Ca2+:H+ Antiporter-2 (CaCA2) Family
2.A.107 - The MntP Mn2+ exporter (MntP) Family
2.A.108 - The Iron/Lead Transporter (ILT) Family
2.A.109 - The Tellurium Ion Resistance (TerC) Family
2.A.113 - The Nickel/cobalt Transporter (NicO) Family
2.A.116 - The Peptidoglycolipid Addressing Protein (GAP) Family
5.A.1 - The Disulfide Bond Oxidoreductase D (DsbD) Family

MACPF Superfamily

Vitug + Saier, unpublished results

1.C.12 - The Thiol-activated Cholesterol-dependent Cytolysin (CDC) Family
1.C.39 - The Membrane Attack Complex/Perforin (MACPF) Family
1.C.97 - The Pleurotolysin Pore-forming (Pleurotolysin) Family

Major Intrinsic Protein (MIP) Superfamily

Reizer, J., A. Reizer, and M.H. Saier, Jr. (1993). The MIP family of integral membrane channel proteins: sequence comparisons, evolutionary relationships, reconstructed pathway of evolution, and proposed functional differentiation of the two repeated halves of the proteins. Crit. Rev. Biochem. Mol. Biol. 28: 235-257.

Park, J.H. and M.H. Saier, Jr. (1996). Phylogenetic characterization of the MIP family of transmembrane channel proteins. J. Membr. Biol. 153: 171-180.

1.A.8 - The Major Intrinsic Protein (MIP) Family
1.A.16 - The Formate-Nitrite Transporter (FNT) Family

Mer Superfamily

Ai Yamaguchi, Dorjee G. Tamang, Milton H Saier, Jr. (2007). Mercury Transport in Bacteria. Water, Air, and Soil Pollution. 182: 219 - 234.

Timothy Mok, Jonathan S. Chen, Maksim A. Shlykov, Maksim A. Shlykov, Milton H. Saier Jr. (2012). Bioinformatic Analyses of Bacterial Mercury Ion (Hg2+) Transporters. Water, Air, and Soil Pollution. 223: 4445 - 4457.

1.A.72 - The Mer Superfamily

MFS Superfamily

The Major Facilitator Superfamily (MFS) is the largest superfamily of secondary carriers known. It includes a few families of proteins that catalyze processes other than secondary transport. For example, evidence suggests that the Major Intrinsic Protein (MIP) family of aquaporins and glycerol channels is related to the MFS as are Rhomboid proteases and the glycosyl transferase (GT) superfamily (unpublished observations). Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81. Reddy, V.S., M.A. Shlykov, R. Castillo, E.I. Sun, and M.H. Saier, Jr. (2012). The major facilitator superfamily (MFS) revisited. FEBS J. 279: 2022-2035.

Yen, M.R., J.S. Chen, J.L. Marquez, E.I. Sun, and M.H. Saier. (2010). Multidrug resistance: phylogenetic characterization of superfamilies of secondary carriers that include drug exporters. Methods Mol Biol 637: 47-64.

2.A.1 - The Major Facilitator Superfamily (MFS)
2.A.2 - The Glycoside-Pentoside-Hexuronide (GPH):Cation Symporter Family
2.A.12 - The ATP:ADP Antiporter (AAA) Family
2.A.17 - The Proton-dependent Oligopeptide Transporter (POT/PTR) Family
2.A.48 - The Reduced Folate Carrier (RFC) Family
2.A.57 - The Equilibrative Nucleoside Transporter (ENT) Family
2.A.60 - The Organo Anion Transporter (OAT) Family
2.A.71 - The Folate-Biopterin Transporter (FBT) Family
2.A.100 - The Ferroportin (Fpn) Family
9.B.111 - The 6 TMS Lysyl tRNA Synthetase (LysS) Family

Mitochondrial Carrier (MC) Superfamily

2.A.29 (32 families)

Kuan, J. and M.H. Saier, Jr. (1993). The mitochondrial carrier family of transport proteins: structural, functional, and evolutionary relationships. Crit. Rev. Biochem. Mol. Biol. 28: 209-233.

Palmieri, F. and C.L. Pierri. (2010). Mitochondrial metabolite transport. Essays Biochem 47: 37-52.

Palmieri, F., C.L. Pierri, A. De Grassi, A. Nunes-Nesi, and A.R. Fernie. (2011). Evolution, structure and function of mitochondrial carriers: a review with new insights. Plant J. 66: 161-181.

2.A.29 - The Mitochondrial Carrier (MC) Family
9.B.25 - The Mitochondrial Inner/Outer Membrane Fusion (MMF) Family

Multidrug/Oligosaccharidyl-lipid/Polysaccharide (MOP) Flippase Superfamily

2.A.66 (12 families)

Hvorup, R.N., B. Winnen, A.B. Chang, Y. Jiang, X.F. Zhou, and M.H. Saier, Jr. (2003). The multidrug/oligosaccharidyl-lipid/polysaccharide (MOP) exporter superfamily. Eur J Biochem 270: 799-813.

Yen, M.R., J.S. Chen, J.L. Marquez, E.I. Sun, and M.H. Saier. (2010). Multidrug resistance: phylogenetic characterization of superfamilies of secondary carriers that include drug exporters. Methods Mol Biol 637: 47-64.

2.A.66 - The Multidrug/Oligosaccharidyl-lipid/Polysaccharide (MOP) Flippase Superfamily

Na+ Transporting Mrp Superfamily

Mrp of Bacillus subtilis is a 7 subunit Na+/H+ antiporter complex (2.A.63.1.4). All subunits are homologous to the subunits in other members of this monovalent cation (K+ or Na+): proton antiporter-3 (CPA3) family as well as subunits in the archaeal hydrogenases (3.D.1.4.1 and 3.D.1.4.2) which share many subunits with NADH dehydrogenase subunits (3.D.1). The largest subunit of the Mrp complex (Mrp A and Mrp D) are homologous to the subunits in NADH dehydrogenases (NDH, ND2, ND4 and ND5 in the fungal NADH dehydrogenase complex) and most other NDHs. (TC#3.D.1) as well are subunits in the F420H2 dehydrogenase of Methanosarcina mazei (TC#3.D.9.1.1). (Zickermann et al. 2015). New subunits in three TC families are homologous, and in all such systems, these subunits may function as Na+/K+ and/or H+ transporters.

2.A.63 - The Monovalent Cation (K+ or Na+):Proton Antiporter-3 (CPA3) Family
3.D.1 - The H+ or Na+-translocating NADH Dehydrogenase (NDH) Family
3.D.9 - The H+-translocating F420H2 Dehydrogenase (F420H2DH) Family

O-Antigen Polymerase (OAPol) Superfamily

9.B.67 - The O-antigen Polymerase (OAP) Family
9.B.128 - The O-antigen Polymerase, WzyE (WzyE) Family

Outer Membrane Pore-forming Protein (OMPP) Superfamily I

The OMPPI Superfamily is an exceptionally large superfamily including over 50 TC OMPP families. This conclusion is based on statistical analyses of primary sequence data (B. L. Reddy and M. H. Saier, Jr., PLOS One, DOI: 10.1371; journal.pone.0152733, April 11, 2016).

1.B.1 - The General Bacterial Porin (GBP) Family
1.B.2 - The Chlamydial Porin (CP) Family
1.B.3 - The Sugar Porin (SP) Family
1.B.4 - The Brucella-Rhizobium Porin (BRP) Family
1.B.5 - The Pseudomonas OprP Porin (POP) Family
1.B.6 - The OmpA-OmpF Porin (OOP) Family
1.B.7 - The Rhodobacter PorCa Porin (RPP) Family
1.B.8 - The Mitochondrial and Plastid Porin (MPP) Family
1.B.9 - The FadL Outer Membrane Protein (FadL) Family
1.B.10 - The Nucleoside-specific Channel-forming Outer Membrane Porin (Tsx) Family
1.B.11 - The Outer Membrane Fimbrial Usher Porin (FUP) Family
1.B.12 - The Autotransporter-1 (AT-1) Family
1.B.13 - The Alginate Export Porin (AEP) Family
1.B.14 - The Outer Membrane Receptor (OMR) Family
1.B.15 - The Raffinose Porin (RafY) Family
1.B.16 - The Short Chain Amide and Urea Porin (SAP) Family
1.B.17 - The Outer Membrane Factor (OMF) Family
1.B.18 - The Outer Membrane Auxiliary (OMA) Protein Family
1.B.19 - The Glucose-selective OprB Porin (OprB) Family
1.B.20 - The Two-Partner Secretion (TPS) Family
1.B.21 - The OmpG Porin (OmpG) Family
1.B.22 - The Outer Bacterial Membrane Secretin (Secretin) Family
1.B.23 - The Cyanobacterial Porin (CBP) Family
1.B.25 - The Outer Membrane Porin (Opr) Family
1.B.26 - The Cyclodextrin Porin (CDP) Family
1.B.31 - The Campylobacter jejuni Major Outer Membrane Porin (MomP) Family
1.B.32 - The Fusobacterial Outer Membrane Porin (FomP) Family
1.B.33 - The Outer Membrane Protein Insertion Porin (Bam Complex) (OmpIP) Family
1.B.35 - The Oligogalacturonate-specific Porin (KdgM) Family
1.B.39 - The Bacterial Porin, OmpW (OmpW) Family
1.B.42 - The Outer Membrane Lipopolysaccharide Export Porin (LPS-EP) Family
1.B.43 - The Coxiella Porin P1 (CPP1) Family
1.B.44 - The Probable Protein Translocating Porphyromonas gingivalis Porin (PorT) Family
1.B.49 - The Anaplasma P44 (A-P44) Porin Family
1.B.54 - The Intimin/Invasin (Int/Inv) or Autotransporter-3 (AT-3) Family
1.B.55 - The Poly Acetyl Glucosamine Porin (PgaA) Family
1.B.57 - The Legionella Major-Outer Membrane Protein (LM-OMP) Family
1.B.60 - The Omp50 Porin (Omp50 Porin) Family
1.B.61 - The Delta-Proteobacterial Porin (Delta-Porin) Family
1.B.62 - The Putative Bacterial Porin (PBP) Family
1.B.66 - The Putative Beta-Barrel Porin-2 (BBP2) Family
1.B.67 - The Putative Beta Barrel Porin-4 (BBP4) Family
1.B.68 - The Putative Beta Barrel Porin-5 (BBP5) Superfamily
1.B.70 - The Outer Membrane Channel (OMC) Family
1.B.71 - The Proteobacterial/Verrucomicrobial Porin (PVP) Family
1.B.72 - The Protochlamydial Outer Membrane Porin (PomS/T) Family
1.B.73 - The Capsule Biogenesis/Assembly (CBA) Family
1.B.78 - The DUF3374 Electron Transport-associated Porin (ETPorin) Family
1.B.80 - The Putative Trans-Outer Membrane Electron Flow Porin (TOM-EF) Family
1.B.81 - The DUF2490 Putative Beta Barrel Porin (DUF2490) Family
9.B.50 - The Outer Membrane Beta-barrel Endoprotease, Omptin (Omptin) Family
9.B.153 - The Putative Beta-Barrel Porin/Alpha Amylase or Phenol_MetA-deg (BBP/AA) Family
9.B.170 - The DUF3187 Putative Porin (DUF3187) Family
9.B.186 - The Putative Lipoprotein Supressor of a ts bamD mutant, YiaD (YiaD) Family

Outer Membrane Pore-forming Protein (OMPP) Superfamily II (MspA Superfamily)

Niederweis, M. (2003). Mycobacterial porins--new channel proteins in unique outer membranes. Mol. Microbiol. 49: 1167-1177; B. L. Reddy and M. H. Saier, Jr., PLOS One, DOI: 10.1371; journal.pone.0152733, April 11, 2016

1.B.24 - The Mycobacterial Porin (MBP) Family
1.B.58 - The Nocardial Hetero-oligomeric Cell Wall Channel (NfpA/B) Family

Outer Membrane Pore-forming Protein (OMPP) Superfamily III

B. L. Reddy and M. H. Saier, Jr., PLOS One, DOI: 10.1371; journal.pone.0152733, April 11, 2016

1.B.28 - The Plastid Outer Envelope Porin of 24 kDa (OEP24) Family
1.B.47 - The Plastid Outer Envelope Porin of 37 kDa (OEP37) Family

Outer Membrane Pore-forming Protein (OMPP) Superfamily IV (Tim17/OEP16/PxMPL (TOP) Superfamily)

B. L. Reddy and M. H. Saier, Jr., PLOS One, DOI: 10.1371; journal.pone.0152733, April 11, 2016 This superfamily includes protein that comprise pores in multicomponent protein translocases as follows: 3.A.8 - [Tim17 (P39515) Tim22 (Q12328) Tim23 (P32897)]; 1.B.69 - [PXMP4 (Q9Y6I8) PMP24 (A2R8R0)]; 3.D.9 - [NDH 21.3 kDa component (P25710)]

1.B.30 - The Plastid Outer Envelope Porin of 16 kDa (OEP16) Family
1.B.69 - The Peroxysomal Membrane Porin 4 (PxMP4) Family
3.A.8 - The Mitochondrial Protein Translocase (MPT) Family

Outer Membrane Pore-forming Protein (OMPP) Superfamily V (Corynebacterial PorA/PorH Superfamily)

Rath, P., O. Saurel, M. Tropis, M. Daffé, P. Demange, and A. Milon. (2013). NMR localization of the O-mycoloylation on PorH, a channel forming peptide from Corynebacterium glutamicum. FEBS Lett. 587: 3687-3691. B. L. Reddy and M. H. Saier, Jr., PLOS One, DOI: 10.1371; journal.pone.0152733, April 11, 2016

1.B.34 - The Corynebacterial Porin A (PorA) Family
1.B.59 - The Outer Membrane Porin, PorH (PorH) Family

P-type ATPase (P-ATPase) Superfamily

3.A.3 (32 families)

Thever, M.D. and M.H. Saier, Jr. (2009). Bioinformatic characterization of p-type ATPases encoded within the fully sequenced genomes of 26 eukaryotes. J. Membr. Biol. 229: 115-130.

Chan, H., V. Babayan, E. Blyumin, C. Gandhi, K. Hak, D. Harake, K. Kumar, P. Lee, T.T. Li, H.Y. Liu, T.C. Lo, C.J. Meyer, S. Stanford, K.S. Zamora, and M.H. Saier, Jr. (2010). The p-type ATPase superfamily. J. Mol. Microbiol. Biotechnol. 19: 5-104.

3.A.3 - The P-type ATPase (P-ATPase) Superfamily

Peroxisomal Peroxin (Pex)11/25/27 (Pex11/25/27) Superfamily

Pex11 of yeast has been shown to be a pore-forming protein (see TC# 1.A.101). It is homologous and similar in size to Pex25 and Pex27. All three proteins are constituents of the Peroxisomal Protein Importer (PPI) Family (see TC# 3.A.20.1.5).

1.A.101 - The Peroxisomal Pore-forming Pex11 (Pex11) Family

Phosphatase - Integral Membrane (5/6/10 TMS) Superfamily

Protein members of the Phosphatase-IM Superfamily can be short with 5 or 6 TMSs or about twice as long with about 10 TMSs. Several of the proteins in both families are annotated as phosphatases.

9.B.105 - The Lead Resistance Fusion Protein (PbrBC) Family
9.B.196 - The Integral Membrane Phosphodiesterase, PAP2 or PgpB (PAP2) Family

Polyphosphate Polymerase/YidH Superfamily

Full length polyphosphate polymerases (TC# 4.E.1) have a C-terminal 3 TMS domain that is in the ubiquitous DUF202 domain/E. coli YidH protein Family (TC# 9.B.51). These small proteins, all with 3 TMSs, are found in bacteria, archaea and eukaryotes.

4.E.1 - The Vacuolar (Acidocalcisome) Polyphosphate Polymerase (V-PPP) Family
9.B.51 - The Uncharacterized DUF202/YidH (YidH) Family

Protein Kinase (PK) Superfamily

Protein kinase domains are sometimes found in transport proteins. These include TC#s 1.A.87.2.1-6, 1.A.105.1.1, 1.I.1.1.3 (with four such proteins in this system), 9.A.15.1.1, 9.B.45.1.3 and 9.B.106.3.1-3. Some of these proteins have channel/transport domains distinct from the kinase domains.

1.I.1 - The Eukaryotic Nuclear Pore Complex (E-NPC) Family
1.A.87 - The Mechanosensitive Calcium Channel (MCA) Family
1.A.105 - The Mixed Lineage Kinase Domain-like (MLKL) Family
9.A.15 - The Autophagy-related Phagophore-formation Transporter (APT) Family
9.B.106 - The Pock Size-determining Protein (PSDP) Family

PTS-AG Superfamily

Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81.

4.A.5 - The PTS Galactitol (Gat) Family
4.A.7 - The PTS L-Ascorbate (L-Asc) Family

PTS-GFL Superfamily

Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81.

Nguyen T.X., Yen M.R., Barabote R.D., Saier M.H. Jr. 2006. Topological predictions for integral membrane permeases of the phosphoenolpyruvate:sugar phosphotransferase system. J Mol Microbiol Biotechnol. 11(6):345-60.

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

4.A.1 - The PTS Glucose-Glucoside (Glc) Family
4.A.2 - The PTS Fructose-Mannitol (Fru) Family
4.A.3 - The PTS Lactose-N,N'-Diacetylchitobiose-β-glucoside (Lac) Family
4.A.4 - The PTS Glucitol (Gut) Family

Resistance-Nodulation-Cell Division (RND) Superfamily

2.A.6 (9 families) Tseng, T.T., K.S. Gratwick, J. Kollman, D. Park, D.H. Nies, A. Goffeau, and M.H. Saier, Jr. (1999). The RND permease superfamily: an ancient, ubiquitous and diverse family that includes human disease and development proteins. J. Mol. Microbiol. Biotechnol. 1: 107-125.

Yen, M.R., J.S. Chen, J.L. Marquez, E.I. Sun, and M.H. Saier. (2010). Multidrug resistance: phylogenetic characterization of superfamilies of secondary carriers that include drug exporters. Methods Mol Biol 637: 47-64.

2.A.6 - The Resistance-Nodulation-Cell Division (RND) Superfamily

RTX-toxin Superfamily

Chen, J.S., V. Reddy, J.H. Chen, M.A. Shlykov, W.H. Zheng, J. Cho, M.R. Yen, and M.H. Saier, Jr. (2011). Phylogenetic characterization of transport protein superfamilies: superiority of SuperfamilyTree programs over those based on multiple alignments. J. Mol. Microbiol. Biotechnol. 21: 83-96.

1.C.11 - The Pore-forming RTX Toxin (RTX-toxin) Family
1.C.56 - The Pseudomonas syringae HrpZ Target Host Cell Membrane Cation Channel (HrpZ) Family
1.C.57 - The Clostridial Cytotoxin (CCT) Family

Synaptotagmin Domain-containing Superfamily

Several proteins in TCDB contain one or two ~100 aa synaptotagmin domains that are involved in calcium and receptor signalling as well as intracellular lipid transport (Pinheiro et al., 2016; PMID# 27731902).

8.A.30 - The Nedd4-Family Interacting Protein-2 (Nedd4) Family
8.A.78 - The Insulin Secretion-regulating Lipid Transporter TMEM24 (TMEM24) Family
9.A.48 - The Unconventional Protein Secretion (UPS) System
9.A.57 - The Extended-Synaptotagmin (E-Syt) Family

Tetraspan Junctional Complex Protein (4JC) Superfamily

Hua, V.B., A.B. Chang, J.H. Tchieu, N.M. Kumar, P.A. Nielsen, and M.H. Saier, Jr. (2003). Sequence and phylogenetic analyses of 4 TMS junctional proteins of animals: connexins, innexins, claudins and occludins. J. Membr. Biol. 194: 59-76; Attwood MM, Krishnan A, Pivotti V, Yazdi S, Almen MS, Schioth HB. Topology based identification and comprehensive classification of four-transmembrane helixcontaining proteins (4TMs) in the human genome. BMC Genomics. 2016 PMID: 27030248; Chou A, Lee A, Hendargo KJ, Reddy VS, Shlykov MA, Kuppusamykrishnan H, Medrano-Soto A, Saier MH Jr. (2017). Characterization of the tetraspan junctional complex (4JC) superfamily. Biochim Biophys Acta. 2017 Mar;1859(3):402-414. PMID 27916633.

1.H.1 - The Claudin Tight Junction (Claudin1) Family
1.H.2 - The Invertebrate PMP22-Claudin (Claudin2) Family
1.A.24 - The Gap Junction-forming Connexin (Connexin) Family
1.A.25 - The Gap Junction-forming Innexin (Innexin) Family
1.A.36 - The Intracellular Chloride Channel (ICC) Family
1.A.64 - The Plasmolipin (Plasmolipin) Family
1.A.81 - The Low Affinity Ca2+ Channel (LACC) Family
1.A.82 - The LHFPL Tetraspan Protein (LTSP) Family
1.A.84 - The Calcium Homeostasis Modulator Ca2+ Channel (CALHM-C) Family
8.A.16 - The Ca+ Channel Auxiliary Subunit γ1-γ8 (CCAγ) Family
9.A.27 - The Non-Classical Protein Exporter (NCPE) Family
9.A.46 - The Clarin (CLRN) Family
9.B.41 - The Occludin (Occludin) Family
9.B.130 - The Tetraspan Vesicle Membrane Protein (TVP) Family
9.B.179 - The MscS/DUF475 (DUF475) Family

Transmembrane Acyl Transferease (TmAT) Superfamily

These acyltransferases usually have 9 or 10 TMSs.

9.B.97 - The Acyltransferase-3/Putative Acetyl-CoA Transporter (ATAT) Family
9.B.169 - The Integral Membrane Protein (8 -10 TMSs) YeiB or DUF418 (YeiB) Family

Transporter-Opsin-G protein-coupled receptor (TOG) Superfamily

Yee, D.C., M.A. Shlykov, A. Västermark, V.S. Reddy, S. Arora, E.I. Sun, and M.H. Saier, Jr. (2013). The transporter-opsin-G protein-coupled receptor (TOG) superfamily. FEBS J. 280: 5780-5800.

1.A.14 - The Calcium Transporter A (CaTA) (formerly the Testis-Enhanced Gene Transfer (TEGT) Family
1.A.26 - The Mg2+ Transporter-E (MgtE) Family
1.A.76 - The Magnesium Transporter1 (MagT1) Family
2.A.43 - The Lysosomal Cystine Transporter (LCT) Family
2.A.52 - The Ni2+-Co2+ Transporter (NiCoT) Family
2.A.58 - The Phosphate:Na+ Symporter (PNaS) Family
2.A.82 - The Organic Solute Transporter (OST) Family
2.A.102 - The 4-Toluene Sulfonate Uptake Permease (TSUP) Family
2.A.112 - The KX Blood-group Antigen (KXA) Family
2.A.123 - The Sweet; PQ-loop; Saliva; MtN3 (Sweet) Family
3.E.1 - The Ion-translocating Microbial Rhodopsin (MR) Family
4.B.1 - The Nicotinamide Ribonucleoside (NR) Uptake Permease (PnuC) Family
9.A.14 - The G-protein-coupled receptor (GPCR) Family
9.B.45 - The Fungal Mating-type Pheromone Receptor (MAT-PR) Family
9.B.191 - The Endoplasmic Reticulum Retention Receptor (KDELR) Family

Urea Transporter/Na+ Exporter (UT/RnfD/NqrB) Superfamily

The Na+ pumping NQR (3.D.5) and RNF (3.D.6) families include protein complexes of six homologous but dissimilar subunits. Two of the six subunits, NqrD and NqrE, and RnfA and RnfD are homologous to each other. However, within 3.D.5 and 3.D.6, only one of the six protein constituents, NqrB and RnfD, respectively, is homologous to Urea Transporters (UT, 1.A.28), and these are believed to be responsible for Na+ transport.

1.A.28 - The Urea Transporter (UT) Family
3.D.5 - The Na+-translocating NADH:Quinone Dehydrogenase (Na-NDH or NQR) Family
3.D.6 - The Putative Ion (H+ or Na+)-translocating NADH:Ferredoxin Oxidoreductase (NFO or RNF) Family

VIC Superfamily

Chang A.B., Lin R., Studley W.K., Tran C.V., Saier M.H. Jr. 2004. Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. Mol Membr Biol. 21(3):171-81.

1.A.1 - The Voltage-gated Ion Channel (VIC) Superfamily
1.A.2 - The Inward Rectifier K+ Channel (IRK-C) Family
1.A.3 - The Ryanodine-Inositol 1,4,5-triphosphate Receptor Ca2+ Channel (RIR-CaC) Family
1.A.4 - The Transient Receptor Potential Ca2+ Channel (TRP-CC) Family
1.A.5 - The Polycystin Cation Channel (PCC) Family
1.A.10 - The Glutamate-gated Ion Channel (GIC) Family of Neurotransmitter Receptors
2.A.38 - The K+ Transporter (Trk) Family

Viral Envelope Fusion Protein (Env-FP) Superfamily

KeyNey

1.G.2 - The Viral Pore-forming Membrane Fusion Protein-2 (VMFP2) Family
1.G.9 - The Syncytin (Syncytin) Family
1.G.12 - The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95) Family
1.G.17 - The Bovine Leukemia Virus Envelop Glycoprotein (BLV-Env) Family
1.G.18 - The SARS-CoV Fusion Peptide in the Spike Glycoprotein Precursor (SARS-FP) Family