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Updated: Jun 26, 2026

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis
08:33

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis

Published on: December 5, 2017

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

Yinghui Mao1, Ariane Abrieu, Don W Cleveland

  • 1Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.

Cell
|July 16, 2003
PubMed

Insights

The mitotic checkpoint ensures correct chromosome attachment. Researchers found CENP-E activates BubR1 kinase, and also silences it after attachment, revealing BubR1

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • The mitotic checkpoint is crucial for accurate chromosome segregation.
  • It prevents anaphase onset until all chromosomes are properly attached to spindle microtubules.
  • BubR1 is an essential kinase in this checkpoint pathway.

Purpose of the Study:

  • To elucidate the role of CENP-E in regulating the mitotic checkpoint kinase BubR1.
  • To understand how BubR1 activity is controlled during mitosis.
  • To investigate the bifunctional roles of BubR1 in checkpoint signaling.

Main Methods:

  • Utilized purified protein components.
  • Employed Xenopus egg extracts for in vitro studies.
  • Investigated the effects of CENP-E antibodies on BubR1 activity.

Main Results:

  • Kinetochore-associated motor CENP-E activates the BubR1 kinase.
  • CENP-E mediates the silencing of BubR1 signaling upon microtubule attachment.
  • BubR1 requires its Mad3 domain for Cdc20 binding, but only a fraction needs kinase activity.

Conclusions:

  • CENP-E plays a dual role in the mitotic checkpoint: activating and silencing BubR1.
  • BubR1 functions both enzymatically (kinase activity) and stoichiometrically (Cdc20 inhibition).
  • This study reveals a novel regulatory mechanism for mitotic checkpoint control.

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