G-protein-coupled receptors (GPCRs) all have a similar struc…
G-protein-coupled receptors (GPCRs) all have a similar structure with ____________ transmembrane domains. When a GPCR binds an extracellular signal, an intracellular G protein, composed of _________ subunits, becomes activated. _________ of the G-protein subunits are tethered to the plasma membrane by short lipid tails. When unstimulated, the α subunit is bound to ________, which is exchanged for _______ on stimulation. The intrinsic ________ activity of the α subunit is important for inactivating the G protein. _______ inhibits this activity of the α subunit, thereby keeping the subunit in an active state. adenylyl cyclase cholera toxin GTPase AMP diacylglycerol phosphodiesterase ATP five seven ATPase four three Ca2+ GDP twelve cAMP GTP two