Gq alpha subunit

guanine nucleotide binding protein (G protein), q polypeptide
Symbol GNAQ
Entrez 2776
HUGO 4390
OMIM 600998
RefSeq NM_002072
UniProt P50148
Other data
Locus Chr. 9 q21
guanine nucleotide binding protein (G protein), alpha 11 (Gq class)
Symbol GNA11
Entrez 2767
HUGO 4379
OMIM 139313
RefSeq NM_002067
UniProt P29992
Other data
Locus Chr. 19 p13.3
guanine nucleotide binding protein (G protein), alpha 14
Symbol GNA14
Entrez 9630
HUGO 4382
OMIM 604397
RefSeq NM_004297
UniProt O95837
Other data
Locus Chr. 9 q21
guanine nucleotide binding protein (G protein), alpha 15 (Gq class)
Symbol GNA15
Entrez 2769
HUGO 4383
OMIM 139314
RefSeq NM_002068
UniProt P30679
Other data
Locus Chr. 19 p13.3

Gq protein (Gαq, or Gq/11) is a heterotrimeric G protein subunit that activates phospholipase C (PLC). PLC in turn hydrolyzes Phosphatidylinositol 4,5-bisphosphate (PIP2) to diacyl glycerol (DAG) and inositol trisphosphate (IP3) signal transduction pathway. DAG acts as a second messenger that activates Protein Kinase C (PKC) and IP3 helps in phosphorylation of some proteins.


There has been much debate about the naming of the Gαq. However, the "q" in the name is arbitrarily named and does not stand for anything in particular. This nomenclature came from Micheal Strathmann and Mel Simon after their discovery of the protein class in 1989. Essentially, the q designation comes from the fact that Michael Strathmann couldn't use the front end of the alphabet "because those early letters were already reserved for a number of classes of subunits, the Gz designation had been taken and Gx seemed too obvious -- and so Gq."


Gq proteins are class of G proteins which work to activate phospholipase C (PLC), participating in a variety of cellular signaling pathways.[1]

The Gq protein works by activating PLC. PLC then cleaves a phospholipid. In the process, phosphatidylinositol 4,5-bisphosphate (PIP2) is cleaved into diacyl glycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG remains bound to the membrane, and IP3 is released as a soluble structure into the cytosol. IP3 then diffuses through the cytosol to bind to IP3 receptors, particular calcium channels in the endoplasmic reticulum (ER). These channels are specific to calcium and only allow the passage of calcium to move through. This causes the cytosolic concentration of calcium to increase, causing a cascade of intracellular changes and activity.[1]

Further reading: Calcium function in vertebrates

In addition, calcium and DAG together work to activate PKC, which goes on to phosphorylate other molecules, leading to altered cellular activity.[1]

Further reading: function of protein kinase C

Examples of GPCR partners

From modulatory neurotransmitter receptors (amine receptors belonging to rhodopsin family), Gq has been shown to be pre-coupled with Gq-coupled receptors physically and is functionally coupled to e.g. the G-protein coupled receptors:[2]

It has been shown that Gq proteins are preassembled (pre-coupled) with Gq-coupled receptors (such as M3 receptor. The common polybasic domain in the C-tail of Gq-coupled receptors is necessary for the receptor-G protein preassembly.[2]


See also


  1. 1 2 3 Alberts B, Lewis J, Raff M, Roberts K, Walter P (2002). Molecular biology of the cell (4th ed.). New York: Garland Science. ISBN 0-8153-3218-1.
  2. 1 2 3 Kou Qin; Chunmin Dong; Guangyu Wu; Nevin A Lambert (August 2011). "Inactive-state preassembly of Gq-coupled receptors and Gq heterotrimers". Nature Chemical Biology. 7 (11): 740–747. doi:10.1038/nchembio.642. PMC 3177959Freely accessible. PMID 21873996.

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