Guanine nucleotide-binding protein G(i) subunit alpha-1 (GNAI1)

Guanine nucleotide-binding protein G(i) subunit alpha-1 (GNAI1) is a member of the heterotrimeric G protein family that mediates inhibitory signaling downstream of many G protein-coupled receptors (GPCRs)[1][2][4]. As the alpha subunit of the Gi1 complex, GNAI1 binds GTP and GDP and possesses intrinsic GTPase activity, functioning as a molecular switch to regulate intracellular signaling pathways. Upon activation by ligand-bound GPCRs, GNAI1 exchanges GDP for GTP, dissociates from the beta and gamma subunits, and inhibits adenylate cyclase, resulting in decreased intracellular cAMP levels and modulation of downstream cAMP-dependent protein kinase activity[1][2][4]. GNAI1 is implicated in processes such as cell proliferation, cell division, and neurological signaling, and serves as a substrate for pertussis toxin. While it is not directly targeted by approved therapeutics, many pharmacological agents exert their effects via modulation of GPCRs that signal through GNAI1[2][4].

Other names

Gi1 protein alpha subunitAdenylate cyclase-inhibiting G alpha proteinGi protein alpha subunitHG1BNEDHISBHeterotrimeric guanine nucleotide-binding protein 1BGiG protein subunit alpha i1

Drugs act indirectly by modulating GPCRs that activate or inhibit GNAI1, which then transduces signal by inhibiting adenylate cyclase, thereby reducing cAMP levels and modulating cell responses\nPertussis toxin irreversibly ADP-ribosylates GNAI1, disabling its function and interrupting inhibitory signaling from affected GPCRs