Cavγ8
Description: calcium channel, voltage-dependent, gamma subunit 8 Gene: cacng8 Alias: cacng8
The protein encoded by CACNG8 (also known as FLJ16240; FLJ30598) is a type I 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 II TARP and a calcium channel gamma subunit. The mRNA for this gene is believed to initiate translation from a non-AUG (CUG) start codon.
http://www.ncbi.nlm.nih.gov/gene/59283
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].
The four c subunits identified as regulators of AMPA receptor function (c2, c3, c4, and c8; the TARPs) are widely expressed in the brain and share highly conserved sequences that are quite distinct from c1 and c6 (Arikkath [1324], Black [478]).
Transcript
| Species | NCBI accession | Length (nt) | |
|---|---|---|---|
| Human | NM_031895.6 | 8850 | |
| Mouse | NM_133190.3 | 2116 | |
| Rat | NM_080696.2 | 1266 |
Protein Isoforms
Isoforms
Post-Translational Modifications
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 cytoplasmic C-terminal regions of the TARPs (to which cacng8 = gamma8 = c8 belongs) contain a number of regulatory sites including a PDZ-binding motif. This PDZ-binding motif (TTPV) is critical for targeting AMPA receptors to the synapse. Chen [1310]
Cavγ8 predicted AlphaFold size
Methodology for AlphaFold size prediction and disclaimer are available here
The four c subunits identified as regulators of AMPA receptor function (c2, c3, c4, and c8; the TARPs) are widely expressed in the brain and share highly conserved sequences that are quite distinct from c1 and c6 (Arikkath [1324], Black [478]).
The most distinct features of the TARPs are the terminal PDZ-binding motifs overlapped with PKA phosphorylation sites. The terminal TTPV motif is known to interact with PSD-95 in the postsynaptic density and the binding is regulated by the PKA motif immediately preceding the PDZ-binding motif (Chetkovich [1325], Choi [1326]). In addition to the critical PDZ-binding motif, the C-terminal regions of the four c subunits known as the TARPs (c2, c3, c4, c8) also contain regulatory sites that control AMPA receptor targeting. (Chen [1310])
References
Black JL
The voltage-gated calcium channel gamma subunits: a review of the literature.
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2003
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Chen RS
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Calcium channel gamma subunits: a functionally diverse protein family.
Cell Biochem. Biophys.,
2007
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Chu PJ
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Calcium channel gamma subunits provide insights into the evolution of this gene family.
Gene,
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Burgess DL
et al.
A cluster of three novel Ca2+ channel gamma subunit genes on chromosome 19q13.4: evolution and expression profile of the gamma subunit gene family.
Genomics,
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Burgess DL
et al.
Identification of three novel Ca(2+) channel gamma subunit genes reveals molecular diversification by tandem and chromosome duplication.
Genome Res.,
1999
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Arikkath J
et al.
Gamma 1 subunit interactions within the skeletal muscle L-type voltage-gated calcium channels.
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Arikkath J
et al.
Auxiliary subunits: essential components of the voltage-gated calcium channel complex.
Curr. Opin. Neurobiol.,
2003
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, 13 (298-307).
Chetkovich DM
et al.
Phosphorylation of the postsynaptic density-95 (PSD-95)/discs large/zona occludens-1 binding site of stargazin regulates binding to PSD-95 and synaptic targeting of AMPA receptors.
J. Neurosci.,
2002
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15
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Choi J
et al.
Phosphorylation of stargazin by protein kinase A regulates its interaction with PSD-95.
J. Biol. Chem.,
2002
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Moss FJ
et al.
The novel product of a five-exon stargazin-related gene abolishes Ca(V)2.2 calcium channel expression.
EMBO J.,
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, 21 (1514-23).
Blom N
et al.
Prediction of post-translational glycosylation and phosphorylation of proteins from the amino acid sequence.
Proteomics,
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, 4 (1633-49).
Credits
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