title: Receptor sorting within endosomal trafficking pathway is facilitated by dynamic actin filaments.
abstract: Early endosomes (EEs) are known to be a sorting station for internalized molecules destined for degradation, recycling, or other intracellular organelles. Segregation is an essential step in such sorting, but the molecular mechanism of this process remains to be elucidated. Here, we show that actin is required for efficient recycling and endosomal maturation by producing a motile force. Perturbation of actin dynamics by drugs induced a few enlarged EEs containing several degradative vacuoles and also interfered with their transporting ability. Actin repolymerization induced by washout of the drug caused the vacuoles to dissociate and individually translocate toward the perinuclear region. We further elucidated that cortactin, an actin-nucleating factor, was required for transporting contents from within EEs. Actin filaments regulated by cortactin may provide a motile force for efficient sorting within early endosomes. These data suggest that actin filaments coordinate with microtubules to mediate segregation in EEs.
authors.affiliation: Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Ohashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Tanabe
authors.forename: Yuji
authors.initials: Y
authors.lastname: Henmi
authors.forename: Kumi
authors.initials: K
authors.lastname: Mesaki
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kohji
authors.initials: K
authors.lastname: Takei
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D051356:Cortactin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics; D059027:Recycling; D022161:Transport Vesicles / Q000378:metabolism*
chemical_list: D000199:Actins; D051356:Cortactin; D034741:RNA, Small Interfering