Activating and silencing the mitotic checkpoint through CENP-E-dependent activation/inactivation of BubR1

Cell. 2003 Jul 11;114(1):87-98. doi: 10.1016/s0092-8674(03)00475-6.


The mitotic checkpoint prevents advance to anaphase prior to successful attachment of every centromere/kinetochore to mitotic spindle microtubules. Using purified components and Xenopus egg extracts, the kinetochore-associated microtubule motor CENP-E is now shown to be the activator of the essential checkpoint kinase BubR1. Since kinase activity and the checkpoint are silenced following CENP-E-dependent microtubule attachment in extracts or binding of CENP-E antibodies that do not disrupt CENP-E association with BubR1, CENP-E mediates silencing of BubR1 signaling. Checkpoint signaling requires the normal level of BubR1 containing a functional Mad3 domain implicated in Cdc20 binding, but only a small fraction need be kinase competent. This supports bifunctional roles for BubR1 in the checkpoint: an enzymatic one requiring CENP-E-dependent activation of its kinase activity at kinetochores and a stoichiometric one as a direct inhibitor of Cdc20.

Publication types

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

MeSH terms

  • Animals
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Extracts
  • Cells, Cultured
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Eukaryotic Cells / cytology
  • Eukaryotic Cells / metabolism*
  • Female
  • Gene Silencing / physiology
  • Genes, cdc / physiology*
  • Kinetochores / metabolism
  • Microtubules / genetics
  • Microtubules / metabolism
  • Mitosis / genetics*
  • Oocytes
  • Protein Binding / genetics
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Structure, Tertiary / genetics
  • Protein-Serine-Threonine Kinases
  • Spindle Apparatus / genetics
  • Spindle Apparatus / metabolism
  • Xenopus laevis


  • Cell Cycle Proteins
  • Cell Extracts
  • Chromosomal Proteins, Non-Histone
  • centromere protein E
  • Protein Kinases
  • Bub1 spindle checkpoint protein
  • Protein-Serine-Threonine Kinases