title: Endosome sorting of beta 2-adrenoceptors is GRK5 independent.
abstract: 1. We have investigated the role of G protein-coupled receptor kinase 5 (GRK5) in the regulation of endosome sorting of human beta(2)-adrenoceptors. 2. Expressing GRK5 at a high level significantly increased the extent of internalization of wild-type beta(2)-adrenoceptors and of an internalization-defective mutant receptor, and increased receptor phosphorylation at serines 355 and 356 in the cytoplasmic tail. 3. Overexpressing GRK5 did not alter beta(2)-adrenoceptor recycling as assessed by immunofluorescence microscopy and radioligand binding assays nor was there any change in receptor downregulation. 4. These data indicate that GRK5 does not regulate the sorting of beta(2)-adrenoceptors in the endocytic pathway.
authors.affiliation: Department of Pediatrics and Molecular Physiology and Biophysics, Baylor College of Medicine, 6621 Fannin, CCC1040, Houston, TX 77030, U.S.A.
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Millman
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Rosenfeld
authors.forename: David J
authors.initials: DJ
authors.lastname: Vaughan
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Nguyen
authors.forename: WenPing
authors.initials: W
authors.lastname: Dai
authors.forename: Estrella
authors.initials: E
authors.lastname: Alpizar-Foster
authors.forename: Richard B
authors.initials: RB
authors.lastname: Clark
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Knoll
authors.forename: Robert H
authors.initials: RH
authors.lastname: Moore
mesh_terms: D002460:Cell Line; D015536:Down-Regulation / Q000502:physiology; D011992:Endosomes / Q000235:genetics / Q000378:metabolism*; D054774:G-Protein-Coupled Receptor Kinase 5; D006801:Humans; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D018343:Receptors, Adrenergic, beta-2; D017346:Protein Serine-Threonine Kinases; D054774:G-Protein-Coupled Receptor Kinase 5; C517898:GRK5 protein, human