title: Myosin IIA is involved in the endocytosis of CXCR4 induced by SDF-1alpha.
abstract: Endocytosis of chemokine receptors regulates signal transduction initiated by chemokines, but the molecular mechanisms underlying this process are not fully defined. In this work, we assessed the involvement of the motor protein nonmuscle myosin heavy chain IIA (MIIA) in the endocytosis of CXCR4 induced by SDF-1alpha (also known as CXCL12) in T lymphocytes. Overexpression of the C-terminal half of MIIA inhibited the ligand-induced endocytosis of CXCR4, but not that of transferrin receptor. Targeting MIIA either by silencing its expression with small interfering RNA (siRNA) or by blebbistatin treatment also inhibited endocytosis of CXCR4. Inhibition of endocytosis of CXCR4 by targeting endogenous MIIA resulted in an increased migration of T cells induced by SDF-1alpha, and in the inhibition of the HIV-1-Env antifusogenic activity of this chemokine. Coimmunoprecipitation and protein-protein binding studies demonstrated that MIIA interacts with both the cytoplasmic tail of CXCR4 and beta-arrestin. Moreover, SDF-1alpha promotes a rapid MIIA-beta-arrestin dissociation. Our data reveal a novel role for MIIA in CXCR4 endocytosis, which involves its dynamic association with beta-arrestin and highlights the role of endogenous MIIA as a regulator of CXCR4 internalization and, therefore, the onset of SDF-1alpha signaling.
authors.affiliation: Servicio de Inmunología, Hospital Universitario de la Princesa, Diego de León, 62, 28006 Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Rey
authors.forename: Agustín
authors.initials: A
authors.lastname: Valenzuela-Fernández
authors.forename: Ana
authors.initials: A
authors.lastname: Urzainqui
authors.forename: María
authors.initials: M
authors.lastname: Yáñez-Mó
authors.forename: Manuel
authors.initials: M
authors.lastname: Pérez-Martínez
authors.forename: Petronila
authors.initials: P
authors.lastname: Penela
authors.forename: Federico
authors.initials: F
authors.lastname: Mayor
authors.forename: Francisco
authors.initials: F
authors.lastname: Sánchez-Madrid
mesh_terms: D019390:Arrestins / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D054377:Chemokine CXCL12 / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D006801:Humans; D024507:Nonmuscle Myosin Type IIA / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D019718:Receptors, CXCR4 / Q000502:physiology*; D011990:Receptors, Transferrin / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013601:T-Lymphocytes / Q000502:physiology; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D006576:Heterocyclic Compounds, 4 or More Rings; D019718:Receptors, CXCR4; D011990:Receptors, Transferrin; D011994:Recombinant Proteins; D000071557:beta-Arrestins; C472645:blebbistatin; D024507:Nonmuscle Myosin Type IIA