Trimeric G protein, complex with RGS4, model

Molecular model of G alpha (a trimeric G protein) in complex with RGS4 (regulator of G-protein signalling, PDB code:1agr), ribbon diagram. G alpha is shown in green with the switch regions I and II in red. RGS4 is shown in blue. The trimeric guanine nucleotide-binding proteins are involved as transducers in various transmembrane signalling systems. The G alpha (s) protein is involved in hormonal regulation of adenylate cyclase: it activates the cyclase in response to beta-adrenergic stimuli, and is regulated by RGS4.