title: Myosin Ib modulates the morphology and the protein transport within multi-vesicular sorting endosomes.
abstract: Members of at least four classes of myosin (I, II, V and VI) have been implicated in the dynamics of a large variety of organelles. Despite their common motor domain structure, some of these myosins, however, are non processive and cannot move organelles along the actin tracks. Here, we demonstrate in the human pigmented MNT-1 cell line that, (1) the overexpression of one of these myosins, myosin 1b, or the addition of cytochalasin D affects the morphology of the sorting multivesicular endosomes; (2) the overexpression of myosin 1b delays the processing of Pmel17 (the product of murine silver locus also named GP100), which occurs in these multivesicular endosomes; (3) myosin 1b associated with endosomes coimmunoprecipitates with Pmel17. All together, these observations suggest that myosin 1b controls the traffic of protein cargo in multivesicular endosomes most probably through its ability to modulate with actin the morphology of these sorting endosomes.
authors.affiliation: Institut Curie, CNRS UMR144, 26 rue d'Ulm, 75248, Paris, Cedex 05, France.
authors.forename: Laura
authors.initials: L
authors.lastname: Salas-Cortes
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Danièle
authors.initials: D
authors.lastname: Tenza
authors.forename: Claire
authors.initials: C
authors.lastname: Wilhelm
authors.forename: Alexander
authors.initials: A
authors.lastname: Theos
authors.forename: Daniel
authors.initials: D
authors.lastname: Louvard
authors.forename: Graça
authors.initials: G
authors.lastname: Raposo
authors.forename: Evelyne
authors.initials: E
authors.lastname: Coudrier
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D003571:Cytochalasin B / Q000494:pharmacology; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D020460:Melanosomes / Q000648:ultrastructure; D024461:Myosin Type I / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D011993:Recombinant Fusion Proteins; D013347:Subcellular Fractions
chemical_list: D011993:Recombinant Fusion Proteins; D003571:Cytochalasin B; D024461:Myosin Type I