title: Differential regulation of endosomal GPCR/β-arrestin complexes and trafficking by MAPK.
abstract: β-Arrestins are signaling adaptors that bind to agonist-occupied G protein-coupled receptors (GPCRs) and target them for endocytosis; however, the mechanisms regulating receptor/β-arrestin complexes and trafficking in endosomes, remain ill defined. Here we show, in live cells, differential dynamic regulation of endosomal bradykinin B2 receptor (B2R) complexes with either β-arrestin-1 or -2. We find a novel role for MAPK in the B2R/β-arrestin-2 complex formation, receptor trafficking and signaling mediated by an ERK1/2 regulatory motif in the hinge domain of the rat β-arrestin-2 (PET(178)P), but not rat β-arrestin-1 (PER(177)P). While the ERK1/2 regulatory motif is conserved between rat and mouse β-arrestin-2, it is surprisingly not conserved in human β-arrestin-2 (PEK(178)P). However, mutation of lysine 178 to threonine is sufficient to confer MAPK sensitivity to the human β-arrestin-2. Furthermore, substitution for a phosphomimetic residue in both the rat and the human β-arrestin-2 (T/K178D) significantly stabilizes B2R/β-arrestin complexes in endosomes, delays receptor recycling to the plasma membrane and maintains intracellular MAPK signaling. Similarly, the endosomal trafficking of β2-adrenergic, angiotensin II type 1 and vasopressin V2 receptors was altered by the β-arrestin-2 T178D mutant. Our findings unveil a novel subtype specific mode of MAPK-dependent regulation of β-arrestins in intracellular trafficking and signaling of GPCRs, and suggest differential endosomal receptor/β-arrestin-2 signaling roles among species.
authors.affiliation: From the Departments of Medicine.
authors.forename: Etienne
authors.initials: E
authors.lastname: Khoury
authors.affiliation: Pharmacology and Therapeutics, and.
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Nikolajev
authors.affiliation: From the Departments of Medicine.
authors.forename: May
authors.initials: M
authors.lastname: Simaan
authors.affiliation: From the Departments of Medicine.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Namkung
authors.affiliation: From the Departments of Medicine, Pharmacology and Therapeutics, and Anatomy and Cell Biology, McGill University Health Center Research Institute, McGill University, Strathcona Anatomy & Dentistry Bldg., Quebec H3A 2B2, Canada stephane.laporte@mcgill.ca.
authors.forename: Stéphane A
authors.initials: SA
authors.lastname: Laporte
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019390:Arrestins / Q000737:chemistry / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D021381:Protein Transport; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605253:ARRB1 protein, human; C000605254:ARRB2 protein, human; C000605255:Arrb1 protein, mouse; C000605256:Arrb1 protein, rat; C000605258:Arrb2 protein, mouse; C000605257:Arrb2 protein, rat; D019390:Arrestins; D043562:Receptors, G-Protein-Coupled; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D020928:Mitogen-Activated Protein Kinases
keywords: Arrestin; Bradykinin B2 Receptor; Cell Signaling; G Protein-coupled Receptor (GPCR); Mitogen-activated Protein Kinase (MAPK); Trafficking