Liganded Gi-activating GPCR acts as a GEF for Gi

Stable Identifier
R-HSA-380073
Type
Reaction [transition]
Species
Homo sapiens
Compartment
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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
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
2748346 Nucleotide sequence for a cDNA encoding the alpha subunit of retinal transducin (GNAT1) isolated from the human eye

Van Dop, C, Medynski, DC, Apone, LM

Nucleic Acids Res 1989
2834384 Presence of three distinct molecular species of Gi protein alpha subunit. Structure of rat cDNAs and human genomic DNAs

Itoh, H, Toyama, R, Kozasa, T, Tsukamoto, T, Matsuoka, M, Kaziro, Y

J Biol Chem 1988
8015379 Human taste cells express the G protein alpha-gustducin and neuron-specific enolase

Takami, S, Getchell, TV, McLaughlin, SK, Margolskee, RF, Getchell, ML

Brain Res Mol Brain Res 1994
Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
guanyl-nucleotide exchange factor activity of Ligand:GPCR complexes that activate Gi:Heterotrimeric G-protein Gi (inactive) [plasma membrane]
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Activity
This event is regulated
Orthologous Events
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