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Blood, 1 July 2008, Vol. 112, No. 1, pp. 34-44. Prepublished online as a Blood First Edition Paper on April 24, 2008; DOI 10.1182/blood-2007-07-102103. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2007-07-102103v1 112/1/34    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Google Scholar Articles by Lagane, B. Articles by Bachelerie, F. PubMed PubMed Citation Articles by Lagane, B. Articles by Bachelerie, F. Related Collections Chemokines, Cytokines, and Interleukins Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  CHEMOKINES, CYTOKINES, AND INTERLEUKINS CXCR4 dimerization and β-arrestin–mediated signaling account for the enhanced chemotaxis to CXCL12 in WHIM syndrome Bernard Lagane1,2, Ken Y. C. Chow1,2, Karl Balabanian1,2, Angélique Levoye1,2, Julie Harriague1,2, Thierry Planchenault1,2, Françoise Baleux3, Nathalie Gunera-Saad4, Fernando Arenzana-Seisdedos1,2, and Françoise Bachelerie1,2 1 Unité de Pathogénie Virale Moléculaire, Institut Pasteur, Paris; 2 Inserm U819, Paris; 3 Unité de Chimie Organique, Institut Pasteur, Paris; and 4 Université Lyon1, UFR Lyon-Sud, URCI-LS, Centre Hospitalier Lyon-Sud, Pierre-Benite, France WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is an immune deficiency linked in many cases to heterozygous mutations causing truncations in the cytoplasmic tail of CXC chemokine receptor 4 (CXCR4). Leukocytes expressing truncated CXCR4 display enhanced responses to the receptor ligand CXCL12, including chemotaxis, which likely impair their trafficking and contribute to the immunohematologic clinical manifestations of the syndrome. CXCR4 desensitization and endocytosis are dependent on β-arrestin (βarr) recruitment to the cytoplasmic tail, so that the truncated CXCR4 are refractory to these processes and so have enhanced G protein–dependent signaling. Here, we show that the augmented responsiveness of WHIM leukocytes is also accounted for by enhanced βarr2-dependent signaling downstream of the truncated CXCR4 receptor. Indeed, the WHIM-associated receptor CXCR41013 maintains association with βarr2 and triggers augmented and prolonged βarr2-dependent signaling, as revealed by ERK1/2 phosphorylation kinetics. Evidence is also provided that CXCR41013-mediated chemotaxis critically requires βarr2, and disrupting the SHSK motif in the third intracellular loop of CXCR41013 abrogates βarr2-mediated signaling, but not coupling to G proteins, and normalizes chemotaxis. We also demonstrate that CXCR41013 spontaneously forms heterodimers with wild-type CXCR4. Accordingly, we propose a model where enhanced functional interactions between βarr2 and receptor dimers account for the altered responsiveness of WHIM leukocytes to CXCL12. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

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