title: The Msd1-Wdr8-Pkl1 complex anchors microtubule minus ends to fission yeast spindle pole bodies.
abstract: The minus ends of spindle microtubules are anchored to a microtubule-organizing center. The conserved Msd1/SSX2IP proteins are localized to the spindle pole body (SPB) and the centrosome in fission yeast and humans, respectively, and play a critical role in microtubule anchoring. In this paper, we show that fission yeast Msd1 forms a ternary complex with another conserved protein, Wdr8, and the minus end-directed Pkl1/kinesin-14. Individual deletion mutants displayed the identical spindle-protrusion phenotypes. Msd1 and Wdr8 were delivered by Pkl1 to mitotic SPBs, where Pkl1 was tethered through Msd1-Wdr8. The spindle-anchoring defect imposed by msd1/wdr8/pkl1 deletions was suppressed by a mutation of the plus end-directed Cut7/kinesin-5, which was shown to be mutual. Intriguingly, Pkl1 motor activity was not required for its anchoring role once targeted to the SPB. Therefore, spindle anchoring through Msd1-Wdr8-Pkl1 is crucial for balancing the Cut7/kinesin-5-mediated outward force at the SPB. Our analysis provides mechanistic insight into the spatiotemporal regulation of two opposing kinesins to ensure mitotic spindle bipolarity.
authors.affiliation: The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, England, UK Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Yukawa
authors.affiliation: The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, England, UK.
authors.forename: Chiho
authors.initials: C
authors.lastname: Ikebe
authors.affiliation: The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, England, UK takashi.toda@crick.ac.uk.
authors.forename: Takashi
authors.initials: T
authors.lastname: Toda
mesh_terms: D016547:Kinesins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D046912:Multiprotein Complexes / Q000378:metabolism; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D064048:Spindle Pole Bodies / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; C521127:Msd1 protein, S pombe; D046912:Multiprotein Complexes; C104160:PKL1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C000599841:Wdr8 protein, S pombe; D016547:Kinesins