title: A potential physiological role for bi-directional motility and motor clustering of mitotic kinesin-5 Cin8 in yeast mitosis.
abstract: The bipolar kinesin-5 Cin8 switches from minus- to plus-end-directed motility under various conditionsin vitroThe mechanism and physiological significance of this switch remain unknown. Here, we show that under high ionic strength conditions, Cin8 moves towards and concentrates in clusters at the minus ends of stable and dynamic microtubules. Clustering of Cin8 induces a switch from fast minus- to slow plus-end-directed motility and forms sites that capture antiparallel microtubules (MTs) and induces their sliding apart through plus-end-directed motility. In early mitotic cells with monopolar spindles, Cin8 localizes near the spindle poles at microtubule minus ends. This localization is dependent on the minus-end-directed motility of Cin8. In cells with assembled bipolar spindles, Cin8 is distributed along the spindle microtubules. We propose that minus-end-directed motility is required for Cin8 clustering near the spindle poles before spindle assembly. Cin8 clusters promote the capture of microtubules emanating from the neighboring spindle poles and mediate their antiparallel sliding. This activity is essential to maximize microtubule crosslinking before bipolar spindle assembly and to induce the initial separation of the spindle poles.
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Ofer
authors.initials: O
authors.lastname: Shapira
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Alina
authors.initials: A
authors.lastname: Goldstein
authors.affiliation: Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA jawdat@ucdavis.edu lgheber@bgu.ac.il.
authors.forename: Jawdat
authors.initials: J
authors.lastname: Al-Bassam
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel jawdat@ucdavis.edu lgheber@bgu.ac.il.
authors.forename: Larisa
authors.identifier: 0000-0003-3759-4001
authors.initials: L
authors.lastname: Gheber
mesh_terms: D016547:Kinesins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D009068:Movement; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D064048:Spindle Pole Bodies / Q000378:metabolism
chemical_list: C075342:CIN8 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016547:Kinesins
keywords: Cin8; Kinesin-5; Microtubules; Mitosis; Mitotic spindle