title: Myosin 1c participates in B cell cytoskeleton rearrangements, is recruited to the immunologic synapse, and contributes to antigen presentation.
abstract: Myosin 1c (Myo1c) is a member of the unconventional class I myosins of vertebrates, which directly link the plasma membrane with the microfilament cortical web. Although this molecular motor has been implicated in cell functions such as cytoskeleton organization, cell motility, nuclear transcription, and endocytosis, its role in hematopoietic cells is largely unknown. In this study, we show that Myo1c is abundantly expressed in murine B lymphocytes and is preferentially located at the plasma membrane, especially in peripheral processes such as microvilli. We observed that this motor concentrates at the growing membrane protrusions generated during B cell spreading and that it is actively recruited to the immune synapse. Interestingly, Myo1c was detected in lipid rafts of B cells and showed strong colocalization with MHC-II, particularly after cross-linking of these molecules. By transfection of a dominant negative form of Myo1c or specific siRNA, we also detected alterations in the spreading and Ag-presenting ability of these cells. The data suggest that Myo1c is involved in the cytoskeleton dynamics and membrane protein anchoring or sorting in B lymphocytes.
authors.affiliation: Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City CP 07360, México.
authors.forename: José L
authors.initials: JL
authors.lastname: Maravillas-Montero
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gillespie
authors.forename: Genaro
authors.initials: G
authors.lastname: Patiño-López
authors.forename: Stephen
authors.initials: S
authors.lastname: Shaw
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Santos-Argumedo
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002469:Cell Separation; D003599:Cytoskeleton / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D054992:Immunological Synapses / Q000276:immunology*; D047468:Immunoprecipitation; D051379:Mice; D008810:Mice, Inbred C57BL; D009218:Myosins / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D009218:Myosins