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BRCA1 downregulates the kinase activity of Polo-like kinase 1 in response to replication stress

Jianqiu Zou1, Khosrow Rezvani, Hongmin Wang

  • 1Basic Biomedical Science Division, Sanford School of Medicine, The University of South Dakota, Vermillion, SD, USA.

Cell Cycle (Georgetown, Tex.)
|September 27, 2013
PubMed

Insights

DNA damage and replication stress trigger breast cancer gene 1 (BRCA1) to inhibit Polo-like kinase 1 (PLK1) activity. BRCA1 modulates interactions with Aurora A and hBora, downregulating PLK1 to aid DNA repair.

Area of Science:

  • Cellular biology
  • Molecular oncology
  • DNA damage response

Background:

  • Cell cycle arrest is crucial for DNA repair following damage or replication stress.
  • Cyclin-dependent kinases (CDKs) and Polo-like kinase 1 (PLK1) activity are downregulated during cell cycle arrest.
  • Breast cancer gene 1 (BRCA1) is a known regulator of CDK inhibition, but its role in PLK1 regulation remains unclear.

Purpose of the Study:

  • To investigate the mechanism by which DNA damage and replication stress inhibit PLK1 activity.
  • To determine the role of BRCA1 in the regulation of PLK1 during cellular stress responses.

Main Methods:

  • Co-immunoprecipitation assays to assess protein-protein interactions.
  • Kinase activity assays to measure PLK1 enzymatic function.
  • Cellular stress induction models (DNA damage and replication stress).

Main Results:

  • DNA damage and replication stress induce the association between BRCA1 and PLK1.
  • BRCA1 actively downregulates PLK1 kinase activity.
  • BRCA1 modulates the interaction dynamics of Aurora A, hBora, and PLK1 to achieve PLK1 inhibition.

Conclusions:

  • BRCA1 plays a critical role in inhibiting PLK1 activity in response to replication stress and DNA damage.
  • BRCA1 acts as a central regulator, coordinating the inhibition of both CDKs and PLK1 during DNA repair.
  • This study elucidates a novel mechanism for PLK1 regulation within the DNA damage response pathway.
Keywords:
BRCA1DNA damagePLK1replication stress

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