G12/G13 alpha subunits explained

guanine nucleotide-binding protein (G protein) alpha 12
Hgncid:	4380
Symbol:	GNA12
Entrezgene:	2768
Omim:	604394
Refseq:	NM_007353
Uniprot:	Q03113
Chromosome:	7
Arm:	p
Band:	22.3

guanine nucleotide-binding protein (G protein), alpha 13
Hgncid:	4381
Symbol:	GNA13
Entrezgene:	10672
Omim:	604406
Refseq:	NM_006572
Uniprot:	Q14344
Chromosome:	17
Arm:	q
Band:	24

G₁₂/G₁₃ alpha subunits are alpha subunits of heterotrimeric G proteins that link cell surface G protein-coupled receptors primarily to guanine nucleotide exchange factors for the Rho small GTPases to regulate the actin cytoskeleton.^[1] Together, these two proteins comprise one of the four classes of G protein alpha subunits.^[2] G protein alpha subunits bind to guanine nucleotides and function in a regulatory cycle, and are active when bound to GTP but inactive and associated with the G beta-gamma complex when bound to GDP.^{[3] [4]} G₁₂/G₁₃ are not targets of pertussis toxin or cholera toxin, as are other classes of G protein alpha subunits.^[5]

G proteins G₁₂ and G₁₃ regulate actin cytoskeletal remodeling in cells during movement and migration, including cancer cell metastasis.^[6] G₁₃ is also essential for receptor tyrosine kinase-induced migration of fibroblast and endothelial cells.^[7]

Genes

• GNA12

See also

• Second messenger system
• G protein-coupled receptor
• Heterotrimeric G protein
• Gs alpha subunit
• Gi alpha subunit
• Gq alpha subunit
• Rho family of GTPases

Notes and References

1. Dhanasekaran N, Dermott JM . Signaling by the G12 class of G proteins . Cell. Signal. . 8 . 4 . 235–45 . 1996 . 8842523 . 10.1016/0898-6568(96)00048-4 .
2. Strathmann MP, Simon MI . G alpha 12 and G alpha 13 subunits define a fourth class of G protein alpha subunits . Proc. Natl. Acad. Sci. U.S.A. . 88 . 13 . 5582–6 . 1991 . 1905812 . 10.1073/pnas.88.13.5582 . 51921 . 1991PNAS...88.5582S . free .
3. Gilman . AG . 1987 . G proteins: transducers of receptor-generated signals . Annual Review of Biochemistry . 56 . 615–649 . 10.1146/annurev.bi.56.070187.003151 . 3113327 .
4. Rodbell . M . 1995 . Nobel Lecture: Signal transduction: Evolution of an idea . Bioscience Reports . 15 . 3 . 117–133 . 10.1007/bf01207453 . 7579038 . 11025853 . 1519115 .
5. Harhammer R, Nürnberg B, Harteneck C, Leopoldt D, Exner T, Schultz G . Distinct biochemical properties of the native members of the G₁₂ G-protein subfamily. Characterization of G alpha 12 purified from rat brain . Biochem. J. . (Pt 1) . 165–71 . 319 . 1996 . Pt 1 . 8870664 . 10.1042/bj3190165. 1217750 .
6. Wang D, Tan YC, Kreitzer GE, Nakai Y, Shan D, Zheng Y, Huang XY . G proteins G12 and G13 control the dynamic turnover of growth factor-induced dorsal ruffles . J. Biol. Chem. . 281 . 43 . 32660–7 . 2006 . 16943201 . 10.1074/jbc.M604588200 . free .
7. Shan D, Chen L, Wang D, Tan YC, Gu JL, Huang XY . The G protein G alpha(13) is required for growth factor-induced cell migration . Dev. Cell . 10 . 6 . 707–18 . 2006 . 16740474 . 10.1016/j.devcel.2006.03.014 . free .