CENP-E kinesin interacts with SKAP protein to orchestrate accurate chromosome segregation in mitosis

J Biol Chem. 2012 Jan 6;287(2):1500-9. doi: 10.1074/jbc.M111.277194. Epub 2011 Nov 22.

Abstract

Mitotic chromosome segregation is orchestrated by the dynamic interaction of spindle microtubules with the kinetochore. Although previous studies show that the mitotic kinesin CENP-E forms a link between attachment of the spindle microtubule to the kinetochore and the mitotic checkpoint signaling cascade, the molecular mechanism underlying dynamic kinetochore-microtubule interactions in mammalian cells remains elusive. Here, we identify a novel interaction between CENP-E and SKAP that functions synergistically in governing dynamic kinetochore-microtubule interactions. SKAP binds to the C-terminal tail of CENP-E in vitro and is essential for an accurate kinetochore-microtubule attachment in vivo. Immunoelectron microscopic analysis indicates that SKAP is a constituent of the kinetochore corona fibers of mammalian centromeres. Depletion of SKAP or CENP-E by RNA interference results in a dramatic reduction of inter-kinetochore tension, which causes chromosome mis-segregation with a prolonged delay in achieving metaphase alignment. Importantly, SKAP binds to microtubules in vitro, and this interaction is synergized by CENP-E. Based on these findings, we propose that SKAP cooperates with CENP-E to orchestrate dynamic kinetochore-microtubule interaction for faithful chromosome segregation.

Publication types

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

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Chromosome Segregation / physiology*
  • Chromosomes, Human / genetics
  • Chromosomes, Human / metabolism*
  • HeLa Cells
  • Humans
  • Kinesin / genetics
  • Kinesin / metabolism
  • Kinetochores / metabolism*
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / genetics
  • Microtubules / metabolism
  • Mitosis / physiology*
  • Spindle Apparatus / genetics
  • Spindle Apparatus / metabolism

Substances

  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • KNSTRN protein, human
  • Microtubule-Associated Proteins
  • centromere protein E
  • Kinesin