title: Rab11 endosomes contribute to mitotic spindle organization and orientation.
abstract: During interphase, Rab11-GTPase-containing endosomes recycle endocytic cargo. However, little is known about Rab11 endosomes in mitosis. Here, we show that Rab11 localizes to the mitotic spindle and regulates dynein-dependent endosome localization at poles. We found that mitotic recycling endosomes bind γ-TuRC components and associate with tubulin in vitro. Rab11 depletion or dominant-negative Rab11 expression disrupts astral microtubules, delays mitosis, and redistributes spindle pole proteins. Reciprocally, constitutively active Rab11 increases astral microtubules, restores γ-tubulin spindle pole localization, and generates robust spindles. This suggests a role for Rab11 activity in spindle pole maturation during mitosis. Rab11 depletion causes misorientation of the mitotic spindle and the plane of cell division. These findings suggest a molecular mechanism for the organization of astral microtubules and the mitotic spindle through Rab11-dependent control of spindle pole assembly and function. We propose that Rab11 and its associated endosomes cocontribute to these processes through retrograde transport to poles by dynein.
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Heidi
authors.initials: H
authors.lastname: Hehnly
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA. Electronic address: stephen.doxsey@umassmed.edu.
authors.forename: Stephen
authors.initials: S
authors.lastname: Doxsey
mesh_terms: D015153:Blotting, Western; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology; D002455:Cell Division; D004398:Dyneins / Q000378:metabolism; D011992:Endosomes / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D012516:Osteosarcoma / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics; D008941:Spindle Apparatus / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D020691:rab GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
chemical_list: D004398:Dyneins; D049452:Green Fluorescent Proteins; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; D014404:Tubulin; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins