title: Beta-arrestin binding to the beta2-adrenergic receptor requires both receptor phosphorylation and receptor activation.
abstract: Homologous desensitization of beta2-adrenergic receptors has been shown to be mediated by phosphorylation of the agonist-stimulated receptor by G-protein-coupled receptor kinase 2 (GRK2) followed by binding of beta-arrestins to the phosphorylated receptor. Binding of beta-arrestin to the receptor is a prerequisite for subsequent receptor desensitization, internalization via clathrin-coated pits, and the initiation of alternative signaling pathways. In this study we have investigated the interactions between receptors and beta-arrestin2 in living cells using fluorescence resonance energy transfer. We show that (a) the initial kinetics of beta-arrestin2 binding to the receptor is limited by the kinetics of GRK2-mediated receptor phosphorylation; (b) repeated stimulation leads to the accumulation of GRK2-phosphorylated receptor, which can bind beta-arrestin2 very rapidly; and (c) the interaction of beta-arrestin2 with the receptor depends on the activation of the receptor by agonist because agonist withdrawal leads to swift dissociation of the receptor-beta-arrestin2 complex. This fast agonist-controlled association and dissociation of beta-arrestins from prephosphorylated receptors should permit rapid control of receptor sensitivity in repeatedly stimulated cells such as neurons.
authors.affiliation: Institute for Pharmacology and Toxicology, Versbacher Strasse 9, D-97078 Würzburg, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Krasel
authors.forename: Moritz
authors.initials: M
authors.lastname: Bünemann
authors.forename: Kristina
authors.initials: K
authors.lastname: Lorenz
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Lohse
mesh_terms: D000818:Animals; D019390:Arrestins / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D054770:G-Protein-Coupled Receptor Kinase 3; D006801:Humans; D007668:Kidney; D007700:Kinetics; D051379:Mice; D010766:Phosphorylation; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D018343:Receptors, Adrenergic, beta-2; D011994:Recombinant Proteins; D000071557:beta-Arrestins; D017868:Cyclic AMP-Dependent Protein Kinases; D054770:G-Protein-Coupled Receptor Kinase 3; C517848:GRK3 protein, human; C517850:GRK3 protein, mouse; D051552:beta-Adrenergic Receptor Kinases