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Plk1 phosphorylation of Topors is involved in its degradation

Xiaoming Yang1, Hongchang Li, Anping Deng

  • 1College of Chemistry, Sichuan University, Chengdu 610064, China. xiaoming4444@gmail.com

Molecular Biology Reports
|October 13, 2009
PubMed

Insights

Topors protein regulates cell growth and tumor suppression. New findings show Topors is crucial for normal mitosis and is degraded when the spindle checkpoint is active, a process regulated by Plk1 phosphorylation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Topors is a DNA topoisomerase I- and p53-binding protein, primarily acting as a p53 regulator.
  • Evidence suggests Topors negatively regulates cell growth and may function as a tumor suppressor.

Purpose of the Study:

  • To investigate the role of Topors in mitotic progression.
  • To elucidate the mechanism of Topors degradation during mitosis.

Main Methods:

  • Depletion of Topors using RNA interference.
  • Activation of the spindle assembly checkpoint using nocodazole.
  • Analysis of Topors phosphorylation and degradation.

Main Results:

  • Topors depletion delays mitotic entry and disrupts mitotic progression.
  • Topors undergoes degradation upon activation of the spindle checkpoint.
  • Phosphorylation of Topors at serine 718 by Polo-like kinase 1 (Plk1) is critical for its degradation.

Conclusions:

  • Topors plays a significant role in normal mitotic progression.
  • Topors degradation is a regulated process dependent on spindle checkpoint activation and Plk1-mediated phosphorylation.

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