TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*8.A.16.1.1









Calcium channel γ1-subunit, CACNG1
Eukaryota
Metazoa
CACNG1 from Homo sapiens
*8.A.16.1.2









Calcium channel γ6-subunit, CACNG6.  Mediates inhibition of the low voltage-activated Cav3.1 channel by direct interaction involving a GxxxA motif in TMS1 (Lin et al. 2008).

Eukaryota
Metazoa
CACNG6 from Homo sapiens
*8.A.16.1.8









Cornichon family AMPA receptor auxiliary protein 2 of 160 aas and 3 TMSs, CNIH-2.  Regulates the trafficking and gating properties of AMPA-selective glutamate receptors (AMPARs). Promotes their targeting to the cell membrane and synapses and modulates their gating properties by regulating their rates of activation, deactivation and desensitization (Shi et al. 2010; Kato and Witkin 2018).

Eukaryota
Metazoa
CNIH-2 of Homo sapiens
*8.A.16.2.1









Transmembrane AMPA receptor (AMPAR) regulatory proteins, also called voltage-dependent Ca2+ channel γ2 subunits, TARPγ2, CACNG2, gamma-2 or Stargazin; regulate Ca(v)2.2 (TC# 1.A.1.11.19) as well as GIRK (TC# 1.A.2.1.3) (Tselnicker and Dascal 2010). TARPγ2 and TARPγ7 (8.A.16.2.5) can substitute for each other (Yamazaki et al. 2015).  TARPs also enhance AMPAR function, altering ligand efficacy and receptor gating kinetics and shaping the postsynaptic response. Stargazin rescues gating deficiencies in AMPARs carrying mutations that destabilize the closed-cleft states of the ligand-binding domain (LBD), suggesting that stargazin stabilizes closed LBD states (MacLean et al. 2014).  For Ca2+-permeable AMPARs, stargazin enhances receptor function by increasing single-channel conductance, slowing channel gating, increasing calcium permeability, and relieving the voltage-dependent block by endogenous intracellular polyamines (McGee et al. 2015).  TARPs alter the conformations of pore-forming subunits and thereby affect antagonist interactions (Cokić and Stein 2008). By shifting the balance between AMPAR activation and desensitization, TARPs markedly facilitate the transduction of spillover-mediated synaptic signaling (Coombs et al. 2017).

Eukaryota
Metazoa
CACNG2 of Homo sapiens (Q9Y698)
*8.A.16.2.2









Voltage-dependent Ca2+ channel γ3 subunit, CACNG3
Eukaryota
Metazoa
CACNG3 of Homo sapiens (O60359)
*8.A.16.2.3









Voltage-dependent Ca2+ channel γ4 subunit, CACNG4
Eukaryota
Metazoa
CACNG4 of Homo sapiens (7656948)
*8.A.16.2.4









Voltage dependent Ca2+ channel γ5 subunit, CACNG5

Eukaryota
Metazoa
CACNG5 of Mus musculus (Q8VHW4)
*8.A.16.2.5









Voltage dependent Ca2+ channel γ7 (γ-7) subunit, CACNG7 or TARP γ7.  Enhances synaptic expression and channel activity of Ca2+ permeable AMPA receptors (TC#1.A.10.1.1) (Studniarczyk et al. 2013; Kato et al. 2007).

Eukaryota
Metazoa
CACNG7 of Homo sapiens (P62955)
*8.A.16.2.6









Voltage dependent Ca2+ channel γ8 subunit, CACNG8.  Interacts with calcineurin to regulate AMPA receptor phosphorylation and trafficking (Itakura et al. 2014).

Eukaryota
Metazoa
CACNG8 of Homo sapiens (Q8WXS5)
*8.A.16.2.7









The cataract-associated protein TMEM114 (222 aas) (Glycosylated) (Maher et al., 2011)

Eukaryota
Metazoa
TMEM114 of Mus musculus (Q9D563)
*8.A.16.2.8









Transmembrane protein 178
Eukaryota
Metazoa
TMEM178 of Homo sapiens
*8.A.16.2.9









Claudin domain-containing protein 1 (Membrane protein GENX-3745)
Eukaryota
Metazoa
CLDND1 of Homo sapiens
*8.A.16.2.10









Voltage-dependent calcium channel gamma-8 subunit, a duplicated 8 TMS protein of 602 aas with two 4 TMS elements, with the first half belonging to subfamily 8.A.16.2 and the second half more similar to subfamily 8.A.16.1. 

Eukaryota
Metazoa
Voltage-dependent calcium channel gamma-8 subunit of Tupaia chinensis (Chinese tree shrew)
*8.A.16.2.11









Voltage-dependent calcium channel gamma-6 subunit, a duplicated 8 TMS protein of 630 aas with two 4 TMS elements, the first half belonging to subfamily 8.A.16.2 and the second half more similar to subfamily 8.A.16.1.






Eukaryota
Metazoa
Voltage-dependent calcium channel gamma-6 subunit of Heterocephalus glaber (Naked mole rat)
*8.A.16.2.12









TARP Cacng2a (Stargazin homologue) of 324 aas.  Regulates the trafficking and gating properties of AMPA-selective glutamate receptors (AMPARs), promoting their targeting to the cell membrane and synapses and modulating their gating properties by slowing their rates of activation, deactivation and desensitization. Regulates all AMPAR subunits. Thought to stabilize the calcium channel in an inactivated (closed) state (Roy et al. 2016).

Eukaryota
Metazoa
Cacng2a of Danio rerio (Zebrafish) (Brachydanio rerio)
*8.A.16.3.1









Tetrameric tetraspanin MP20 (4 TMS scaffold protein; Gonen et al., 2007)
Eukaryota
Metazoa
Tetraspanin MP20 of Rattus norvegicus (P54825)
*8.A.16.3.2









Uncharacterized protein of 273 aas and 4 TMSs.  According to Pfam, it belongs to the Claudin2 superfamily.

TMEM202 homologue of Homo sapiens (Human)
*8.A.16.4.1









Invertebrate claudin-like cell junctional protein, Vab-1, of 211 aas and 4 TMSs.  Regulates cell adhesion, intercellular signalling, cell morphology and paracellular small molecule passage (Simske and Hardin 2011).

Eukaryota
Metazoa
Vab-1 of Caenorhabditis elegans
*8.A.16.4.2









Uncharacterized protein of 198 aas and 4 TMSs

Eukaryota
Metazoa
UP of Capitella teleta (Polychaete worm)
*8.A.16.5.1









Germ cell-specific gene 1 protein of 349 aas and 4 TMSs, GSG1. 

Eukaryota
Metazoa
GSG1 of Homo sapiens
*8.A.16.5.2









Uncharacterized protein of 245 aas and 4 TMSs.

Eukaryota
Metazoa
UP of Branchiostoma floridae (Florida lancelet)
*8.A.16.5.3









Germ cell-specific gene-1-like (GSG1L) protein of 331 aas and 4 TMS in a 1 (N-terminal) + 3 TMS arrangement.  Calcium-permeable AMPA receptors (TC# 1.A.10) are specific for the neurotransmitter glutamate. They contribute to various forms of synaptic plasticity. Alterations in their expression or regulation are seen in a number of neurological conditions including stroke, motor neuron disease, and cocaine addiction. Several groups of auxiliary transmembrane proteins have been described that enhance the function and cell-surface expression of AMPARs, but GSG1L decreases channel conductance and calcium permeability while increasing polyamine-dependent rectification by diminishing outward current (McGee et al. 2015). GSG1L favors the AMPAR desensitized state, where channel closure is facilitated by large structural rearrangements in the AMPAR extracellular domain, with ligand-binding domain dimers losing their local 2-fold rotational symmetry. AMPAR auxiliary subunits probably share a modular architecture(Twomey et al. 2017).

Eukaryota
Metazoa
GSG1L OF Homo sapiens
*8.A.16.6.1









Voltage-dependent Ca2+ channel γ-like subunit (211 aas; 3 TMSs) (Klugbauer et al., 2000)
Eukaryota
Metazoa
CcgL of Mus musculus (Q9JJV3)