title: Differential expression and distribution of ezrin, radixin and moesin in human natural killer cells.
abstract: Cytoskeleton plays a crucial role in natural killer cell function. In this study the expression and subcellular distribution of ezrin, radixin and moesin, a family of proteins that connect actin filaments to many membrane structures, were evaluated in human NK cells. The results showed that NK cells expressed all these proteins, while NK cell-deprived peripheral blood leukocytes and purified T lymphocytes did not express radixin. Only ezrin changed its distribution following IL-2 activation and all three ezrin, moesin and radixin were polarized on uropods of adherent natural killer cells. Ezrin and radixin co-localized with the perforin granules at the intimate sites of contact between NK and the target cells, while moesin remains uniformly distributed on the membrane of NK cells. Ezrin, radixin and perforin co-localization was undetected in non-lytic conjugates and inhibited by treatment with actin depolymerizing agents. These results suggest that ezrin and radixin may exert a role in NK activity, particularly in the trafficking of perforin granules to the NK/target cells contact site. Moreover, our data suggest that radixin may represent an additional biological marker of human NK cells and that this protein may hold a specific role in NK cell function.
authors.affiliation: Laboratory of Immunology, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Ramoni
authors.forename: Francesca
authors.initials: F
authors.lastname: Luciani
authors.forename: Francesca
authors.initials: F
authors.lastname: Spadaro
authors.forename: Luana
authors.initials: L
authors.lastname: Lugini
authors.forename: Francesco
authors.initials: F
authors.lastname: Lozupone
authors.forename: Stefano
authors.initials: S
authors.lastname: Fais
mesh_terms: D001798:Blood Proteins / Q000032:analysis* / Q000235:genetics; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007694:Killer Cells, Natural / Q000737:chemistry*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D008840:Microfilament Proteins / Q000032:analysis* / Q000235:genetics; D018613:Microscopy, Confocal; D054353:Perforin; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics; D052899:Pore Forming Cytotoxic Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099149:Ezrin
chemical_list: D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D054353:Perforin; D010750:Phosphoproteins; D052899:Pore Forming Cytotoxic Proteins; D000099149:Ezrin; C071058:moesin; C071776:radixin