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Regulation of polo-like kinase 1 by DNA damage and PP2A/B55α

Ling Wang1, Qingyuan Guo, Laura A Fisher

  • 1a Department of Oral Biology; College of Dentistry ; University of Nebraska Medical Center ; Lincoln , NE USA.

Cell Cycle (Georgetown, Tex.)
|December 9, 2014
PubMed

Insights

DNA damage upregulates a phosphatase that inhibits Plk1 (Polo-like kinase 1), promoting cell cycle checkpoint recovery. This involves PP2A and B55α, crucial for regulating Plk1 activity after DNA damage.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Polo-like kinase 1 (Plk1) regulates mitotic progression and DNA damage checkpoint.
  • Plk1 inhibition is necessary for checkpoint activation after DNA damage, but its regulation remains unclear.

Purpose of the Study:

  • To elucidate the mechanism of Plk1 regulation in response to DNA damage.
  • To identify the phosphatase responsible for Plk1 inhibition and its regulation.

Main Methods:

  • Utilized Xenopus egg extracts to study Plk1 phosphorylation and dephosphorylation.
  • Investigated the association between PP2A, B55α, and Plk1 using biochemical assays.
  • Examined the role of ATM/ATR and checkpoint kinases in regulating PP2A/Plk1 association.

Main Results:

  • Identified PP2A as the primary phosphatase targeting Plk1 at Thr-210 in interphase extracts.
  • Showed that DNA damage upregulates PP2A activity toward Plk1.
  • Demonstrated that B55α mediates PP2A/Plk1 association, which is enhanced by DNA damage via ATM/ATR and checkpoint kinases.

Conclusions:

  • A phosphatase-dependent mechanism regulates Plk1 activity in response to DNA damage.
  • PP2A, targeted by B55α, plays a key role in Plk1 dephosphorylation and checkpoint recovery.
  • This pathway is critical for maintaining genomic stability after DNA damage.
Keywords:
B55αDNA damagePP2APlk1checkpoint recovery

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