Phosducin is a protein kinase A-regulated G-protein regulator.
Signal transduction by G-protein-coupled receptors is regulated by various mechanisms acting at the receptor level; those studied most thoroughly are from the beta-adrenergic receptor/Gs/adenylyl cyclase system. We report here a regulatory mechanism occurring at the level of the G proteins themselves. A protein with M(r) 33,000 that inhibits Gs-GTPase activity was purified from bovine brain. This protein is very similar or identical to phosducin, a protein previously thought to be specific for retina and pineal gland. Recombinant phosducin inhibited the GTPase activity of several G proteins, and also inhibited Gs-mediated adenylyl cyclase activation. Blockade of its inhibitory effects by protein kinase A suggests that phosducin may be part of a complex regulatory network controlling G-protein-mediated signalling.
Bauer
P H
PH
Laboratory of Molecular Biology, University of Munich, Max-Planck-Institute of Biochemistry, Martinsried, Germany.
Müller
S
S
Puzicha
M
M
Pippig
S
S
Obermaier
B
B
Helmreich
E J
EJ
Lohse
M J
MJ
D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000502:physiology; D002417:Cattle; D005136:Eye Proteins / Q000502:physiology*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020555:GTP-Binding Protein Regulators; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015870:Gene Expression; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D015398:Signal Transduction
D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D010750:Phosphoproteins; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; C065631:phosducin; D011494:Protein Kinases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases