Reactome | Liganded Gi-activating GPCR acts as a GEF for Gi

Liganded Gi-activating GPCR acts as a GEF for Gi

Stable Identifier

R-HSA-380073

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytoplasmic side of plasma membrane

ReviewStatus

5/5

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Liganded Gi-activating GPCR acts as a GEF for Gi

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The liganded receptor undergoes a conformational change, generating a signal that is propagated in a manner that is not completely understood to the the G-protein. This stimulates the exchange of GDP for GTP in the G-protein alpha subunit, activating the G-protein. This event is negatively regulated by some Activators of G protein signaling (AGS) proteins, a class of proteins identified in yeast functional screens for proteins able to activate G protein signaling in the absence of a G protein–coupled receptor (GPCR) (Cismowski et al. 1999, Takesono et al. 1999). AGS proteins contain G protein regulatory (GPR) motifs (also referred to as the GoLoco motif) that bind and stabilize the Galpha subunit in its GDP-bound conformation (Mochizuki et al. 1996, Peterson et al. 2000, Cao et al. 2004, Blumer & Lanier 2014). Some RGS proteins similarly bind to Galpha preventing the exchange of GDP for GTP (Soundararajan et al. 2008).

Literature References

PubMed ID	Title	Journal	Year
2748346	Nucleotide sequence for a cDNA encoding the alpha subunit of retinal transducin (GNAT1) isolated from the human eye Van Dop, C, Apone, LM, Medynski, DC	Nucleic Acids Res	1989
2534964	Alpha transducin is present in blue-, green-, and red-sensitive cone photoreceptors in the human retina Lerea, CL, Bunt-Milam, AH, Hurley, JB	Neuron	1989
2834384	Presence of three distinct molecular species of Gi protein alpha subunit. Structure of rat cDNAs and human genomic DNAs Itoh, H, Tsukamoto, T, Kozasa, T, Matsuoka, M, Kaziro, Y, Toyama, R	J Biol Chem	1988
8015379	Human taste cells express the G protein alpha-gustducin and neuron-specific enolase Margolskee, RF, Getchell, TV, Takami, S, McLaughlin, SK, Getchell, ML	Brain Res Mol Brain Res	1994