title: Protein kinase A regulates AKAP250 (gravin) scaffold binding to the beta2-adrenergic receptor.
abstract: A-kinase-anchoring protein 250 (AKAP250; gravin) acts as a scaffold that binds protein kinase A (PKA), protein kinase C and protein phosphatases, associating reversibly with the beta(2)-adrenergic receptor. The receptor-binding domain of the scaffold and the regulation of the receptor-scaffold association was revealed through mutagenesis and biochemical analyses. The AKAP domain found in other members of this superfamily is essential for the scaffold-receptor interactions. Gravin constructs lacking the AKAP domain displayed no binding to the receptor. Metabolic labeling studies in vivo demonstrate agonist-stimulated phosphorylation of gravin and enhanced gravin-receptor association. Analysis of the AKAP domain revealed two canonical PKA sites phosphorylated in response to elevated cAMP, blocked by PKA inhibitor, and essential for scaffold-receptor association and for resensitization of the receptor. The AKAP appears to provide the catalytic PKA activity responsible for phosphorylation of the scaffold in response to agonist activation of the receptor as well as for the association of the scaffold with the receptor, a step critical to receptor resensitization.
authors.affiliation: Departments of Pharmacology and Physiology and Biophysics, Heath Sciences Center, SUNY/Stony Brook, Stony Brook, NY 11794-8651, USA.
authors.forename: Jiangchuan
authors.initials: J
authors.lastname: Tao
authors.forename: Hsien-Yu
authors.initials: HY
authors.lastname: Wang
authors.forename: Craig C
authors.initials: CC
authors.lastname: Malbon
mesh_terms: D054758:A Kinase Anchor Proteins; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002294:Carcinoma, Squamous Cell; D018797:Cell Cycle Proteins; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D017931:DNA Primers; D049452:Green Fluorescent Proteins; D006801:Humans; D007700:Kinetics; D008164:Luminescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014407:Tumor Cells, Cultured
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D018797:Cell Cycle Proteins; D017931:DNA Primers; D008164:Luminescent Proteins; D010446:Peptide Fragments; D011506:Proteins; D018343:Receptors, Adrenergic, beta-2; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases