title: Microtubule-sliding activity of a kinesin-8 promotes spindle assembly and spindle-length control.
abstract: Molecular motors play critical roles in the formation of mitotic spindles, either through controlling the stability of individual microtubules, or by crosslinking and sliding microtubule arrays. Kinesin-8 motors are best known for their regulatory roles in controlling microtubule dynamics. They contain microtubule-destabilizing activities, and restrict spindle length in a wide variety of cell types and organisms. Here, we report an antiparallel microtubule-sliding activity of the budding yeast kinesin-8, Kip3. The in vivo importance of this sliding activity was established through the identification of complementary Kip3 mutants that separate the sliding activity and microtubule-destabilizing activity. In conjunction with Cin8, a kinesin-5 family member, the sliding activity of Kip3 promotes bipolar spindle assembly and the maintenance of genome stability. We propose a slide-disassemble model where the sliding and destabilizing activity of Kip3 balance during pre-anaphase. This facilitates normal spindle assembly. However, the destabilizing activity of Kip3 dominates in late anaphase, inhibiting spindle elongation and ultimately promoting spindle disassembly.
authors.affiliation: Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Su
authors.forename: Hugo
authors.initials: H
authors.lastname: Arellano-Santoyo
authors.forename: Didier
authors.initials: D
authors.lastname: Portran
authors.forename: Jeremie
authors.initials: J
authors.lastname: Gaillard
authors.forename: Marylin
authors.initials: M
authors.lastname: Vantard
authors.forename: Manuel
authors.initials: M
authors.lastname: Thery
authors.forename: David
authors.initials: D
authors.lastname: Pellman
mesh_terms: D015153:Blotting, Western; D042822:Genomic Instability; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D053141:Organelle Size; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: C075342:CIN8 protein, S cerevisiae; C108256:KIP3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016547:Kinesins