Minus-end-directed Kinesin-14 motors align antiparallel microtubules to control metaphase spindle length

Dev Cell. 2014 Oct 13;31(1):61-72. doi: 10.1016/j.devcel.2014.07.023.

Abstract

During cell division, a microtubule-based mitotic spindle mediates the faithful segregation of duplicated chromosomes into daughter cells. Proper length control of the metaphase mitotic spindle is critical to this process and is thought to be achieved through a mechanism in which spindle pole separation forces from plus-end-directed motors are balanced by forces from minus-end-directed motors that pull spindle poles together. However, in contrast to this model, metaphase mitotic spindles with inactive kinesin-14 minus-end-directed motors often have shorter spindle lengths, along with poorly aligned spindle microtubules. A mechanistic explanation for this paradox is unknown. Using computational modeling, in vitro reconstitution, live-cell fluorescence microscopy, and electron microscopy, we now find that the budding yeast kinesin-14 molecular motor Kar3-Cik1 can efficiently align spindle microtubules along the spindle axis. This then allows plus-end-directed kinesin-5 motors to efficiently exert the outward microtubule sliding forces needed for proper spindle bipolarity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Kinesin / metabolism*
  • Microtubule Proteins / metabolism
  • Microtubule-Associated Proteins / metabolism
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Models, Biological*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Spindle Apparatus / metabolism*
  • Spindle Apparatus / ultrastructure

Substances

  • CIK1 protein, S cerevisiae
  • KAR3 protein, S cerevisiae
  • Microtubule Proteins
  • Microtubule-Associated Proteins
  • Saccharomyces cerevisiae Proteins
  • Kinesin