Molecular model of G alpha (a trimeric G protein)
in complex with RGS4, close-up view. G alpha is
shown in magenta, with the switch regions I, II
and III in green, RGS4 in pink. Alpha helices are
represented by cylinders. 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 cyclse: it
activates the cyclase in response to beta-
adrenergic stimuli, and is regulated by RGS4.
