title: Identification of a motif in the carboxyl terminus of CXCR2 that is involved in adaptin 2 binding and receptor internalization.
abstract: Agonist treatment of cells expressing the chemokine receptor, CXCR2, induces receptor phosphorylation and internalization through a dynamin-dependent mechanism. In the present study, we demonstrate that a carboxyl terminus-truncated mutant of CXCR2 (331T), which no longer undergoes agonist-induced phosphorylation, continues to undergo ligand-induced internalization in HEK293 cells. This mutant receptor exhibits reduced association with beta-arrestin 1 but continues to exhibit association with adaptin 2 alpha and beta subunits. Replacing Leu320-321 and/or Ile323-Leu324 with Ala (LL320,321AA, IL323,324AA, and LLIL320,321,323,324AAAA) in wild-type CXCR2 or 331T causes little change in ligand binding and signaling through Ca(2+) mobilization but greatly impairs the agonist-induced receptor sequestration and ligand-mediated chemotaxis. The LL320,321AA, IL323,324AA, and LLIL320,321,323,324AAAA mutants of CXCR2 exhibit normal binding to beta-arrestin 1 but exhibit decreased binding to adaptin 2alpha and beta. These data demonstrate a role for the LLKIL motif in the carboxyl terminus of CXCR2 in receptor internalization and cell chemotaxis and imply a role for adaptin 2 in the endocytosis of CXCR2.
authors.affiliation: Veterans Affairs Medical Center, Nashville, Tennessee 37212-2637, USA.
authors.forename: G H
authors.initials: GH
authors.lastname: Fan
authors.forename: W
authors.initials: W
authors.lastname: Yang
authors.forename: X J
authors.initials: XJ
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Qian
authors.forename: A
authors.initials: A
authors.lastname: Richmond
mesh_terms: D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019390:Arrestins / Q000378:metabolism / Q000502:physiology; D002460:Cell Line; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D004622:Embryo, Mammalian; D006801:Humans; D007668:Kidney; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D023063:Receptors, Interleukin-8B / Q000819:agonists / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins
chemical_list: C000605253:ARRB1 protein, human; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; C000605256:Arrb1 protein, rat; D019390:Arrestins; D008024:Ligands; D008565:Membrane Proteins; D010446:Peptide Fragments; D023063:Receptors, Interleukin-8B; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins