Guanine nucleotide-binding protein G(s) subunit alpha (Gsα)

Guanine nucleotide-binding protein G(s) subunit alpha (Gsα) is the prototypic alpha subunit of the heterotrimeric G protein complex (G protein stimulatory, Gs), encoded by the GNAS gene in humans[3][8]. When a G protein-coupled receptor (GPCR) is activated by a ligand, the Gsα subunit undergoes a GDP–GTP exchange, dissociates from the Gβγ dimer, and stimulates adenylyl cyclase, resulting in increased intracellular cyclic AMP (cAMP)[3][4]. This cAMP pathway regulates diverse physiological responses, including hormone signaling, neurotransmission, cardiac function, and metabolic regulation[1][3]. Gsα is a GTPase, cycling between inactive (GDP-bound) and active (GTP-bound) states to modulate downstream effectors[1][3]. Mutations in GNAS or abnormal Gsα signaling are implicated in several diseases, such as pseudohypoparathyroidism, McCune-Albright syndrome, some endocrine tumors, and certain cancers[3]. While many drugs affect the Gsα pathway indirectly by acting on its upstream GPCRs, there are no direct small-molecule drugs targeting the Gsα protein due to its essential and widespread role in cell signaling[3][8].

Other names

Gs alpha proteinGs alpha subunitGsαGNAS (gene)Gs proteinStimulatory G protein alpha subunit

Activation by GPCR agonists leads to GTP loading on Gsα, dissociation from Gβγ, and stimulation of adenylyl cyclase, increasing cAMP. Toxins (e.g., cholera toxin) ADP-ribosylate Gsα, locking it in its active state and stimulating persistent cAMP production.