G-Protein alpha-i signaling
Guanine nucleotide binding protein alpha inhibiting activity
polypeptide 1 (G-protein
alpha-i) coupled receptors interact with trimeric G-protein
alpha-i/G-protein beta/gamma, which causes exchange of GDP for GTP bound
to G protein alpha subunits and dissociation of G-protein
alpha-i, directly stimulates kinase activity of tyrosine-protein kinase
v-src sarcoma viral oncogene homolog (c-SRC) by binding to
its catalytic domain and changing conformation of c-SRC. In
turn, c-SRC activates v-Ha-ras Harvey rat sarcoma viral
oncogene homolog (H-Ras)/V-raf-1 murine leukemia viral
oncogene homolog 1 (c-Raf-1)/Mitogen-activated protein
kinase kinase 1 and 2
protein kinase 1 and 3 (Erk (MAPK1/3))
pathway via phosphorylation of adaptor protein SHC transforming protein 1
(SHC) and recruitment of adaptor protein Growth factor
receptor-bound protein 2 (GRB2) and positive regulator of
RAS guanine nucleotide exchange protein Son of sevenless homolog
(SOS), leading to cell proliferation and activation of
transcription factor signal transducer and activator of transcription 3
alpha-i mediates activation of RAP1 GTPase activating protein
(RAP1GAP1). RAP1GAP1 transforms
RAP1A member of RAS oncogene family (RAP-1A) and inhibits
V-raf murine sarcoma viral oncogene homolog B1
(MAPK1/3) pathway. 
G-protein alpha-i inhibits some
Adenylate cyclases activity and decreases cAMP
concentration in the cell .
Regulator of G-protein signaling
(RGS) proteins are a family of proteins that have been shown
to act as GTPase-activating proteins, which attenuate signaling by heterotrimeric G
proteins. RGS7, RGS10, RGS11, RGS14, and
RGS18 directly bind to G-protein alpha-i and
selectively inhibit G protein alpha-i function .
Caveolin-1 interacts with
G-protein alpha-i subunits and can functionally suppress
their activity .
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