TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
2.A.69.1.1









Auxin efflux carrier, PIN-FORMED1 (PIN1) (Reinhardt et al., 2003; Carraro et al. 2012). Catalyzes auxin efflux without the participation of any other protein (Petrasek et al., 2006).  PIN1 determines the direction of intercellular auxin flow (Wang et al. 2014). It consists of two TMS bundles, each of 5 TMSs at the N-terminus and the C-terminus of the protein (NodzyƄski et al. 2016), confirming previous bioinformatic predictions (Mansour et al. 2007). Arabidopsis VASCULATURE COMPLEXITY AND CONNECTIVITY (VCC) (TC# 8.A.175) is a plant-specific transmembrane protein that controls the development of veins in cotyledons. Yanagisawa et al. 2021 showed that the expression and localization of PIN1 is altered in vcc developing cotyledons, and that overexpression of PIN1-GFP partially rescues vascular defects of vcc mutants. Genetic analyses suggested that VCC and PINOID (PID), a kinase that regulates PIN1 polarity, are both required for PIN1-mediated control of vasculature development. VCC expression is upregulated by auxin, likely as part of a positive feedback loop for the progression of vascular development. VCC and PIN1 localized to the plasma membrane in pre-procambial cells but were actively redirected to vacuoles in procambial cells for degradation. In the vcc mutant, PIN1 failed to properly polarize in pre-procambial cells during the formation of basal strands, and instead, it was prematurely degraded in vacuoles. VCC plays a role in the localization and stability of PIN1, which is crucial for the transition of pre-procambial cells into procambial cells that are involved in the formation of basal lateral strands in embryonic cotyledons (Yanagisawa et al. 2021). Three inward-facing conformational structures of Arabidopsis thaliana PIN1: the apo state, bound to the natural auxin indole-3-acetic acid (IAA), and in complex with the polar auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) have been solved (Yang et al. 2022). The transmembrane domain of PIN1 shares a conserved NhaA fold. In the substrate-bound structure, IAA is coordinated by both hydrophobic stacking and hydrogen bonding. NPA competes with IAA for the same site in an intracellular pocket, but with a much higher affinity (Yang et al. 2022). PIN-FORMED is required for shoot phototropism/gravitropism and facilitates meristem formation in Marchantia polymorpha (Fisher et al. 2023). Phytopathogens causes worldwide crop losses. Parmagnani et al. 2023 showed that microbial volatile organic compound (mVOC; 1-nonanol and 1-dodecanol) profile of Erwinia amylovora, enhances A. thaliana shoot and root growth. E. amylovora mVOCs triggered early signaling events including plasma transmembrane potential Vm depolarization, cytosolic Ca2+ fluctuations, K+-gated channel activity, and reactive oxygen species (ROS) and nitric oxide (NO) bursts from a few minutes to 16 h upon exposure. These early events were followed by the modulation of the expression of genes involved in plant growth and defense responses as well as responses to phytohormones, including abscisic acid, gibberellin, and auxin (including via the efflux carriers PIN1 and PIN3). A unique mutation in PIN-FORMED1 has been identified, and a genetic pathway for reduced sensitivity of Arabidopsis roots to N-1-naphthylphthalamic acid has been proposed (Huang et al. 2023).

Eukaryota
Viridiplantae, Streptophyta
PIN1 of Arabidopsis thaliana
2.A.69.1.2









Auxin transporter, ethylene-insensitive root 1 (EIR1) auxin:H+ symporter
Eukaryota
Viridiplantae, Streptophyta
EIR1 of Arabidopsis thaliana
2.A.69.1.3









Auxin efflux carrier, PIN7 (promotes embryonic axis formation) (Friml et al., 2003)
Eukaryota
Viridiplantae, Streptophyta
PIN7 of Arabidopsis thaliana (NP_849923)
2.A.69.1.4









Auxin efflux facilitator PIN3: functions in auxin redistribution through the root cap in response to the gravity sensors, ARL2 (Q6XL73) and ARG1 (Q9ZSY2). Both ARG1 and ARL2 are DnaJ homologues and show regions homologous to translocation proteins, NPL1 and Sec63 (3.A.5.8.1 and 3.A.5.9.1, respectively). Cryo-EM structures of AtPIN3 in the apo state and in complex with its substrate indole-3-acetic acid (IAA) and the inhibitor N-1-naphthylphthalamic acid (NPA) at 2.6-3.0 Å resolution have been determined (Su et al. 2022). AtPIN3 exists as a homodimer, with TMSs 1, 2, and 7 in the scaffold domain involved in dimerization. The dimeric AtPIN3 forms a large, joint extracellular-facing cavity at the dimer interface while each subunit adopts an inward-facing conformation. The structural basis for the recognition of IAA and NPA were revealed and elucidated the molecular mechanism of NPA inhibition. The AtPIN3 structures support an elevator-like model for the transport of auxin, whereby the transport domains undergo up-down rigid-body motions and the dimerized scaffold domains remain static (Su et al. 2022). CslPIN3 is involved in the regulation of root growth and development as well as auxin accumulation in tea plants (Hu et al. 2023).

Eukaryota
Viridiplantae, Streptophyta
PIN3 of Arabidopsis thaliana
(Q9S7Z8).
2.A.69.1.5









Auxin efflux carrier #10, PIN10/SLM1 (important for development; orthologous to A. thaliana PIN1 (Zhou et al., 2011)).

Eukaryota
Viridiplantae, Streptophyta
PIN10 of Medicago truncatula (Q673E5)
2.A.69.1.6









Putative auxin efflux carrier component 8 (AtPIN8)
Eukaryota
Viridiplantae, Streptophyta
PIN8 of Arabidopsis thaliana
2.A.69.1.7









Auxin efflux carrier, PIN5.  Regulates auxin homeostasis and metabolism.  Mediates auxin transport across the endoplasmic reticular membrane, for the cytosol to the ER lumen (Mravec et al. 2009).

Eukaryota
Viridiplantae, Streptophyta
PIN5 of Arabidopsis thaliana
2.A.69.1.8









The auxin efflux carrier, AEC3 or PIN1, of 634 aas and 10 TMSs, plays a role in fruit development (Li et al. 2017).

Eukaryota
Viridiplantae, Streptophyta
AEC3 of Momordica charantia (bitter gourd)
2.A.69.1.9









Pin1B of 554 aas and 10 TMSs in a 5 + 5 TMS arrangement with a large hydrophilic loop between the two hydroophobic halves. This auxin transporter, OsPIN1b, is a regulator of leaf inclination in rice (Oryza sativa L.) (Zhang et al. 2023).

Eukaryota
Viridiplantae, Streptophyta
Pin1B of Oryza sativa L.
2.A.69.2.1









AEC family member of 416 aas and 10 TMSs in a 5 + 5 TMS arrangement, with a large hydrophilic loop between the two repeat units.

Bacteria
Euglenozoa
AEC family member of Trypanosoma cruzi (E7LII7)
2.A.69.2.2









Poorly characterized transporter YBR287w.  Deletion of the gene leads to poor growth on glucose-minimal medium at 15 degrees C in the FY 1679 genetic background, but is not involved in mating or sporulation (Dueñas et al. 1999).  

Eukaryota
Fungi, Ascomycota
YBR287w of Saccharomyces cerevisiae
2.A.69.2.3









Auxin efflux carrier family member

Eukaryota
Fungi, Ascomycota
AEC homologue of Aspergillus flavus (B8MZ51)
2.A.69.2.4









AEC family member

Eukaryota
Evosea
AEC family member of Entamoeba histolytica (C4MAS5)
2.A.69.2.5









Uncharacterized protein of 616 aas and 11 TMSs in a 5 + 6 arrangement

Eukaryota
Rhodophyta
UP of Cyanidioschyzon merolae
2.A.69.2.6









Uncharacterized transporter, nonessential for growth or sporulation, YLR152c, of 576 aas and 10 TMSs (Watson 2001).

Eukaryota
Fungi, Ascomycota
UP of Saccharomyces cerevisiae
2.A.69.2.7









Uncharacterized protein of 442 aas and 10 TMSs in a 5 + 5 TMS arrangement.

Eukaryota
Viridiplantae, Streptophyta
UP of Citrus clementina
2.A.69.3.1









AEC homologue

Bacteria
Actinomycetota
AEC homologue of Streptomyces coelicolor
2.A.69.3.2









Malate transporter (MleP) homologue

Bacteria
Pseudomonadota
MleP homologue of Dickeya dadantii (E0SFK1)
2.A.69.3.3









Putative malonate transporter, MdcF
Bacteria
Pseudomonadota
MdcF of Klebsiella pneumoniae
2.A.69.3.4









Putative malonate transporter, MdcF

Bacteria
Pseudomonadota
MdcF of Rhizobium meliloti
2.A.69.3.5









Uncharacterized transporter YfdV
Bacteria
Pseudomonadota
YfdV of Escherichia coli O6:H1
2.A.69.3.6









Putative MdcF malonate transporter of 316 aas and 10 TMSs.

Bacteria
Pseudomonadota
MdcF homologue of Rhizobium loti
2.A.69.3.7









AEC family transporter, auxin efflux carrier, of 318 aas and 10 TMSs in a 5 + 5 TMS arrangement. The efflux mechanism of the substrate, indole 3-acetic acid, has been examined (Rai et al. 2021).

Bacteria
Bacillota
AEC of Bacillus licheniformis
2.A.69.3.8









GPR155 (GP155) of 870 aas and possibly 17 TMSs in a 15 + 2 TMS arrangement.  The N-terminal 15 TMSs may consist of 3 repeats, each of 5 TMSs in a LSLSL (L = large; S = small peak of hydrophobicity).  It may play a role in several types of cancer (Lee et al. 2022).  GPR155 matches the first 10 TMSs (5 + 5 TMS arrangement while TMSs 6 - 10 are similar to the N-terminal half of the sodium bile transporter of the AsbT (SLC10) family.  TMSs 11 - 17 are similar to GPCR proteins with 7 TMSs (Gyimesi and Hediger 2022). Lysosomal GPCR-like protein LYCHOS (GRP155) signals cholesterol sufficiency to mTORC1 (Shin et al. 2022).

Eukaryota
Metazoa, Chordata
GPR155 of Homo sapiens
2.A.69.4.1









Putative membrane permease-like protein. May belong to the BART superfamily (297aas; 10TMS)

Bacteria
Chlorobiota
permease-like protein of Chlorobium luteolum (Q3B5D8)
2.A.69.4.2









Uncharacterized transporter MJ1031
Archaea
Euryarchaeota
MJ1031 of Methanocaldococcus jannaschii
2.A.69.4.3









Uncharacterized transporter MTH_1382
Archaea
Euryarchaeota
MTH_1382 of Methanothermobacter thermautotrophicus
2.A.69.4.4









AEC homologue

Bacteria
Myxococcota
AEC homologue of Myxococcus xanthus
2.A.69.4.5









Malate permease, MleP (Labarre et al. 1996). Activated a few minutes after rehydration (Costantini et al. 2011).

Bacteria
Bacillota
MleP of Oenococcus (Leuconostoc) oeni
2.A.69.4.6









Putative auxin efflux carrier of 333 aas and 10 TMSs.

Bacteria
Actinomycetota
Auxin efflux carrier of Bifidobacterium longum
2.A.69.4.7









Uncharacterized protein of 308 aas and 10 TMSs (Hug et al. 2016).

Bacteria
Candidatus Peregrinibacteria
UP of Candidatus Peribacter riflensis
2.A.69.4.8









Uncharacterized protein of 388 aas and 10 TMSs in a 5 + 5 TMS arrangement.

Eukaryota
Evosea
UP of Entamoeba histolytica