title: Gravin-mediated formation of signaling complexes in beta 2-adrenergic receptor desensitization and resensitization.
abstract: Agonist-induced desensitization and resensitization of G-protein-linked receptors involve the interaction of receptors with protein kinases, phosphatases, beta-arrestin, and clathrin organized by at least one scaffold protein. The dynamic composition of the signaling complexes and the role of the scaffold protein AKAP250 (gravin) in agonist-induced attenuation and recovery of beta-adrenergic receptors were explored by co-immunoprecipitation of target elements, antisense suppression, and confocal microscopy. Gravin associated with unstimulated receptor, and the association was increased significantly after agonist stimulation for up to 60 min. Agonist stimulation also induced a robust association of the receptor-gravin complex with protein kinases A and C, G-protein-linked receptor kinase-2, beta-arrestin, and clathrin. Confocal microscopy of the green fluorescence protein-tagged beta(2)-adrenergic receptor showed that the receptor underwent sequestration after agonist stimulation. Suppression of gravin expression via antisense oligodeoxynucleotides disrupted agonist-induced association of the receptor with G-protein-linked receptor kinase-2, beta-arrestin, and clathrin as well as receptor recovery from desensitization. Gravin deficiency also inhibited agonist-induced sequestration. These data reveal that gravin-mediated formation of signaling complexes with protein kinases/phosphatases, beta-arrestin, and clathrin is essential in agonist-induced internalization and resensitization of G-protein-linked receptors.
authors.affiliation: Department of Molecular Pharmacology, Diabetes and Metabolic Diseases Research Program, University Medical Center, State University of New York, Stony Brook, New York 11794-8651, USA.
authors.forename: F
authors.initials: F
authors.lastname: Lin
authors.forename: H y
authors.initials: Hy
authors.lastname: Wang
authors.forename: C C
authors.initials: CC
authors.lastname: Malbon
mesh_terms: D054758:A Kinase Anchor Proteins; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D019390:Arrestins / Q000378:metabolism; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002966:Clathrin / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D054769:G-Protein-Coupled Receptor Kinase 2; D009838:Oligodeoxyribonucleotides; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D011506:Proteins / Q000502:physiology*; D018343:Receptors, Adrenergic, beta-2 / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D000318:Adrenergic beta-Agonists; D019390:Arrestins; D018797:Cell Cycle Proteins; D002966:Clathrin; D009838:Oligodeoxyribonucleotides; D011506:Proteins; D018343:Receptors, Adrenergic, beta-2; D000071557:beta-Arrestins; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; C496567:GRK2 protein, human; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2