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cacng7

calcium channel, voltage-dependent, gamma subunit 7
Synonyms: cacng7. Symbol: Cacng7

Introductions


The protein encoded by CACNG7 is a type II transmembrane AMPA receptor regulatory protein (TARP). TARPs regulate both trafficking and channel gating of the AMPA receptors. This gene is part of a functionally diverse eight-member protein subfamily of the PMP-22/EMP/MP20 family and is located in a cluster with two family members, a type I TARP and a calcium channel gamma subunit. http://www.ncbi.nlm.nih.gov/gene/59284

Genes


Phylogenetic analysis suggests that all c subunits evolved from a single ancestral gene through tandem repeat and chromosome duplication (Burgesse [1312], Chu [1311]). Based on sequence homology and chromosomal linkage the c subunits can be divided into three clusters: (c1, c6), (c5, c7), and (c2, c3, c4, c8) (Burgesse [1312], Chu [1311]). See also the phylogenetic tree, fig.2 in Black [478].

c5 and c7 are encoded by five exons in contrast to all other c subunits, which are encoded by four exons (Moss [1336], Chu [1311]). A protein originally identified as mouse c5 (Klugbauer [1328]) is currently named transmembrane protein 37 (Tmem37, NCBI database). Although Tmem37 is also a tetraspanin protein with the GLW motif characteristic of the pfam0082 protein family, its gene consists of only two exons, indicating a divergence from other c subunit genes during evolution. Based on phylogenetic evidence, Chu et al. proposed that Tmem37 should not be considered a member of the calcium channel c family (Chu [1311]). This conclusion is further supported by the observation that Tmem37 does not share the chromosomal linkage to c4 and c1 in human (Burgess [1313]), mouse and rat (Chu [1311]) that is seen for c5 (Table 2 in Chen [1310]).

Cacng7 : calcium channel, voltage-dependent, gamma subunit 7

RGD ID Chromosome Position Species
628807 1 64114233-64140485 Rat
732587 7 3336685-3366537 Mouse
732586 19 54416071-54446268 Human

Transcripts


Acc No Sequence Length Source
NM_080695 NCBI
NM_133189 NCBI
NM_031896 NCBI

Ontologies


Accession Name Definition Evidence
GO:0016021 integral to membrane Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane. IEA
GO:0016020 membrane Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins. IEA

Interactions


Proteins


Structures


The eight calcium channel c subunits share a predicted structure that includes four transmembrane domains with intracellular N- and C- termini (Fig. 1 in Chen [1310]). They are members of a large protein superfamily (pfam00822, a subset of the tetraspanin supergroup) that also includes claudins, proteins that are important components of tight junctions in epithelia. The c subunits share with the claudins a conserved GLW motif of unknown significance in the first extracellular loop. Chen [1310]

The c5 and c7 subunits are highly expressed in brain tissue and lack a C-terminal PDZ-binding motif in comparison to other gamma subunits (Chu [1311], Moss [1336]).

c5, c7: c5, and c7 are palmitoylated at both the N- and C- termini. Additionally, their C-terminal tails contain tyrosine phosphorylation sites. Chen [1310]

Distributions


Expressions


Functionals


c7 subunit dramatically reduced current density produced by the Cav2.2 subunit in Xenopus oocytes and COS-7 cells (Moss [1336]). However, when expressed in sympathetic neurons c7 failed to affect pre-existing HVA Ca2+ channels. Therefore, confirmation of the physiological influence of c7 on calcium current remains elusive. (Chen [1310])

γ7, which is homologous to γ5, regulates stability of certain mRNAs (Ferron [1342]) and, along with γ2 and γ8, controls trafficking and gating of AMPA receptors (Tomita [1343], Kato [1344]). It thus may be involved in ischemic cardiomyopathy (Gronich [1341]).

Kinetics


Models


References


[1310 : 17652770]
[1336 : 11927536]
[1312 : 11170751]
[1313 : 10613843]
[1311 : 11738816]
[1328 : 10734232]
[1341 : 20090424]
[1342 : 18923037]
[1343 : 12771129]
[1344 : 17475805]

Credits