When a ligand binds to a GPCR, it induces a conformational change in the receptor. This change is transmitted to an associated G protein, which is composed of three subunits: alpha, beta, and gamma. Upon activation, the G protein exchanges GDP for GTP on the alpha subunit, causing the dissociation of the G protein into the alpha subunit and the beta-gamma dimer. These subunits then go on to activate or inhibit various downstream effectors, such as adenylate cyclase or phospholipase C, leading to a cellular response.
