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
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GRCm38: Ensembl release 89: ENSMUSG00000027523 - Ensembl, May 2017
"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
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.
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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 ]