Guanine nucleotide-binding proteins (G proteins) function as transducers in numerous signaling pathways controlled by G protein-coupled receptors (GPCRs). Signaling involves the activation of adenylyl cyclases, resulting in increased levels of the signaling molecule cAMP (PubMed:2022671, PubMed:9395396, PubMed:11087399, PubMed:15591060, PubMed:16766715, PubMed:19243146). GNAS functions downstream of several GPCRs, including beta-adrenergic receptors. Stimulates the Ras signaling pathway via RAPGEF2 (By similarity). Heterotrimeric G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site (PubMed:9395396, PubMed:9417641, PubMed:10427002, PubMed:11087399, PubMed:15591060, PubMed:16766715, PubMed:19243146). Interacts with CRY1; the interaction may block GPCR-mediated regulation of cAMP concentrations. Interacts with ADCY6 and stimulates its adenylyl cyclase activity (By similarity). Interacts with ADCY2 and ADCY5 (PubMed:9395396, PubMed:9417641, PubMed:10427002, PubMed:11087399, PubMed:15591060, PubMed:16766715, PubMed:19243146). Stimulates the ADCY5 adenylyl cyclase activity (By similarity). Interaction with SASH1 (By similarity). Interacts with GASL2L2 (By similarity). The GNAS locus is imprinted in a complex manner, giving rise to distinct paternally, maternally and biallelically expressed proteins. Crystal structures were determined for GNAS in complex with an adenylyl cyclase catalytic domain that was reconstructed from ADCY2 and ADCY5 N- and C-terminal domains. Belongs to the G-alpha family. G(s) subfamily.