title: Moesin interacts with the cytoplasmic region of intercellular adhesion molecule-3 and is redistributed to the uropod of T lymphocytes during cell polarization.
abstract: During activation, T lymphocytes become motile cells, switching from a spherical to a polarized shape. Chemokines and other chemotactic cytokines induce lymphocyte polarization with the formation of a uropod in the rear pole, where the adhesion receptors intercellular adhesion molecule-1 (ICAM-1), ICAM-3, and CD44 redistribute. We have investigated membrane-cytoskeleton interactions that play a key role in the redistribution of adhesion receptors to the uropod. Immunofluorescence analysis showed that the ERM proteins radixin and moesin localized to the uropod of human T lymphoblasts treated with the chemokine RANTES (regulated on activation, normal T cell expressed, and secreted), a polarization-inducing agent; radixin colocalized with arrays of myosin II at the neck of the uropods, whereas moesin decorated the most distal part of the uropod and colocalized with ICAM-1, ICAM-3, and CD44 molecules. Two other cytoskeletal proteins, beta-actin and alpha-tubulin, clustered at the cell leading edge and uropod, respectively, of polarized lymphocytes. Biochemical analysis showed that moesin coimmunoprecipitates with ICAM-3 in T lymphoblasts stimulated with either RANTES or the polarization- inducing anti-ICAM-3 HP2/19 mAb, as well as in the constitutively polarized T cell line HSB-2. In addition, moesin is associated with CD44, but not with ICAM-1, in polarized T lymphocytes. A correlation between the degree of moesin-ICAM-3 interaction and cell polarization was found as determined by immunofluorescence and immunoprecipitation analysis done in parallel. The moesin-ICAM-3 interaction was specifically mediated by the cytoplasmic domain of ICAM-3 as revealed by precipitation of moesin with a GST fusion protein containing the ICAM-3 cytoplasmic tail from metabolically labeled Jurkat T cell lysates. The interaction of moesin with ICAM-3 was greatly diminished when RANTES-stimulated T lymphoblasts were pretreated with the myosin-disrupting drug butanedione monoxime, which prevents lymphocyte polarization. Altogether, these data indicate that moesin interacts with ICAM-3 and CD44 adhesion molecules in uropods of polarized T cells; these data also suggest that these interactions participate in the formation of links between membrane receptors and the cytoskeleton, thereby regulating morphological changes during cell locomotion.
authors.affiliation: Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, 28006 Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Serrador
authors.forename: J L
authors.initials: JL
authors.lastname: Alonso-Lebrero
authors.forename: M A
authors.initials: MA
authors.lastname: del Pozo
authors.forename: H
authors.initials: H
authors.lastname: Furthmayr
authors.forename: R
authors.initials: R
authors.lastname: Schwartz-Albiez
authors.forename: J
authors.initials: J
authors.lastname: Calvo
authors.forename: F
authors.initials: F
authors.lastname: Lozano
authors.forename: F
authors.initials: F
authors.lastname: Sánchez-Madrid
mesh_terms: D015703:Antigens, CD; D000943:Antigens, Differentiation; D001798:Blood Proteins / Q000032:analysis; D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology*; D018925:Chemokines / Q000494:pharmacology; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D003598:Cytoskeletal Proteins; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D008840:Microfilament Proteins; D010750:Phosphoproteins / Q000032:analysis; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D013601:T-Lymphocytes / Q000737:chemistry* / Q000166:cytology* / Q000187:drug effects; D000099149:Ezrin
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D001798:Blood Proteins; D015815:Cell Adhesion Molecules; D018925:Chemokines; D003598:Cytoskeletal Proteins; D018960:Hyaluronan Receptors; D018799:Intercellular Adhesion Molecule-1; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011506:Proteins; D000099149:Ezrin; C483616:ICAM3 protein, human; C071058:moesin; C071776:radixin