title: Phosphorylated mu-opioid receptor purified from rat brains lacks functional coupling with Gi1, a GTP-binding protein in reconstituted lipid vesicles.
abstract: The effects of phosphorylation of a mu-opioid receptor on signal transduction to G-protein were studied. The mu-opioid receptor purified from rat whole brains was reconstituted with purified Gi1 in phosphatidylcholine vesicles. DAGO, a mu-opioid agonist at 1 microM-1 mM increased GTPase activity by 10-110% of control, in a concentration-dependent manner. When the mu-opioid receptor was phosphorylated by cyclic AMP-dependent protein kinase prior to reconstitution with Gi1, the DAGO-stimulation was markedly reduced (20% increase at 1 mM DAGO).
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Harada
authors.forename: H
authors.initials: H
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Katada
authors.forename: M
authors.initials: M
authors.lastname: Ui
authors.forename: M
authors.initials: M
authors.lastname: Satoh
mesh_terms: D000818:Animals; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D008081:Liposomes; D010713:Phosphatidylcholines; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D017450:Receptors, Opioid, mu; D015398:Signal Transduction
chemical_list: D004745:Enkephalins; D008081:Liposomes; D010713:Phosphatidylcholines; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D019204:GTP-Binding Proteins