GNAS Identifiers Aliases , AHO, C20orf45, GNAS1, GPSA, GSA, GSP, NESP, POH, SCG6, SgVI, GNAS complex locus, PITA3 GNAS External IDs OMIM: 139320 MGI: 95777 HomoloGene: 55534 GeneCards: GNAS
Gene location (Mouse) Chr. Chromosome 2 (mouse)  Band 2 H4|2 97.89 cM Start 174,284,320 bp  End 174,346,744 bp  Orthologs Species Human Mouse Entrez Ensembl UniProt RefSeq (mRNA) RefSeq (protein) Location (UCSC) Chr 20: 58.84 – 58.91 Mb Chr 2: 174.28 – 174.35 Mb PubMed search   Wikidata
G ( s alpha subunit G, αs G) is a subunit of the sα heterotrimeric G protein G that s stimulates the cAMP-dependent pathway by activating adenylyl cyclase. G sα is a GTPase that functions as a cellular signaling protein.
G sα is the founding member of one of the four families of heterotrimeric G proteins, defined by the alpha subunits they contain: the G αs family, G, αi/G αo family G, and αq family G. α12/G α13 family The Gs-family has only two members: the other member is G  olf, named for its predominant expression in the olfactory system. In humans, G sα is encoded by the GNAS complex locus, while G olfα is encoded by the GNAL gene.
Function [ edit ]
The general function of G
s is to activate intracellular signaling pathways in response to activation of cell surface G protein-coupled receptors (GPCRs). GPCRs function as part of a three-component system of receptor-transducer-effector.  The transducer in this system is a  heterotrimeric G protein, composed of three subunits: a Gα protein such as G sα, and a complex of two tightly linked proteins called Gβ and Gγ in a Gβγ complex.  When not stimulated by a receptor, Gα is bound to  GDP and to Gβγ to form the inactive G protein trimer.  When the receptor binds an activating ligand outside the cell (such as a  hormone or neurotransmitter), the activated receptor acts as a guanine nucleotide exchange factor to promote GDP release from and GTP binding to Gα, which drives dissociation of GTP-bound Gα from Gβγ.  In particular, GTP-bound, activated G  sα binds to adenylyl cyclase to produce the second messenger cAMP, which in turn activates the cAMP-dependent protein kinase (also called Protein Kinase A or PKA).  Cellular effects of G  sα acting through PKA are described here.
Although each GTP-bound G
sα can activate only one adenylyl cyclase enzyme, amplification of the signal occurs because one receptor can activate multiple copies of G s while that receptor remains bound to its activating agonist, and each G sα-bound adenylyl cyclase enzyme can generate substantial cAMP to activate many copies of PKA.
Receptors [ edit ]
The G protein-coupled receptors that couple to the G
s family proteins include:
See also [ edit ]
References [ edit ]
^ a b c
GRCh38: Ensembl release 89: ENSG00000087460 - Ensembl, May 2017
^ a b c
GRCm38: Ensembl release 89: ENSMUSG00000027523 - Ensembl, May 2017
"Human PubMed Reference:".
"Mouse PubMed Reference:".
Ellis C, Nature Reviews Drug Discovery GPCR Questionnaire Participants (July 2004). "The state of GPCR research in 2004". Nature Reviews. Drug Discovery. 3 (7): 575, 577–626. doi: 10.1038/nrd1458. PMID 15272499.
^ a b c d e
Gilman AG (1987). "G proteins: transducers of receptor-generated signals". Annual Review of Biochemistry. 56: 615–649. doi: 10.1146/annurev.bi.56.070187.003151.
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Rodbell M (1995). "Nobel Lecture: Signal transduction: Evolution of an idea". Bioscience Reports. 15 (3): 117–133. doi: 10.1007/bf01207453.
Purves D, Augustine GJ, Fitzpatrick D, Hall WC, LaMantia AS, White LE, eds. (2007). Neuroscience (4th ed.). New York: W. H. Freeman. p. 155. ISBN . 978-0-87893-697-7
External links [ edit ]