title: Clathrin box in G protein-coupled receptor kinase 2.
abstract: beta(1)-Adrenergic receptor (beta(1)AR) shows the resistance to agonist-induced internalization. However, beta(1)AR can internalize as G protein-coupled receptor kinase 2 (GRK2) is fused to its carboxyl terminus. Internalization of the beta(1)AR and GRK2 fusion protein (beta(1)AR/GRK2) is dependent on dynamin but independent of beta-arrestin and phosphorylation. The beta(1)AR/GRK2 fusion protein internalizes via clathrin-coated pits and is found to co-localize with the endosome that contains transferrin. The fusion proteins consisting of beta(1)AR and various portions of GRK2 reveal that the residues 498-502 in the carboxyl-terminal domain of GRK2 are critical to promote internalization of the fusion proteins. This domain contains a consensus sequence of a clathrin-binding motif defined as a clathrin box. In vitro binding assays show that the residues 498-502 of GRK2 bind the amino-terminal domain of clathrin heavy chain to almost the same extent as beta-arrestin1. The mutation of the clathrin box in the carboxyl-terminal domain of GRK2 results in the loss of the ability to promote internalization of the fusion protein. GRK2 activity increases and then decreases as the concentration of clathrin heavy chain increases. Taken together, these results imply that GRK2 contains a functional clathrin box and directly interacts with clathrin to modulate its function.
authors.affiliation: Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shiina
authors.forename: K
authors.initials: K
authors.lastname: Arai
authors.forename: S
authors.initials: S
authors.lastname: Tanabe
authors.forename: N
authors.initials: N
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Haga
authors.forename: T
authors.initials: T
authors.lastname: Nagao
authors.forename: H
authors.initials: H
authors.lastname: Kurose
mesh_terms: D000595:Amino Acid Sequence; D019390:Arrestins / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D002966:Clathrin / Q000737:chemistry / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry* / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010766:Phosphorylation; D021381:Protein Transport; D018342:Receptors, Adrenergic, beta-1 / Q000187:drug effects / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014168:Transferrin / Q000378:metabolism*; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D002966:Clathrin; D018342:Receptors, Adrenergic, beta-1; D011993:Recombinant Fusion Proteins; D014168:Transferrin; D000071557:beta-Arrestins; D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases; D007545:Isoproterenol