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EAPP modulates the activity of p21 and Chk2

Peter Andorfer1, Ludwig Schwarzmayr, Hans Rotheneder

  • 1Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.

Cell Cycle (Georgetown, Tex.)
|May 17, 2011
PubMed

Insights

Genomic instability in cancer is linked to DNA damage response. EAPP protein overexpression disrupts cell cycle checkpoints by affecting Chk2 activity, potentially promoting tumor development.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Genetics

Background:

  • Genomic instability, including microsatellite instability (MIN) and chromosomal instability (CIN), is crucial for cancer development.
  • Cell cycle checkpoints and DNA repair mechanisms, particularly the response to double-strand breaks involving ATM, Chk2, and p53, are vital for maintaining genomic integrity.
  • EAPP, a nuclear phosphoprotein upregulated in tumors, plays a role in cellular homeostasis and its overexpression impacts cell cycle arrest and apoptosis.

Purpose of the Study:

  • To investigate the role of EAPP in regulating DNA damage response pathways.
  • To elucidate the mechanism by which EAPP influences Chk2 activity and its implications for genomic stability.
  • To understand the contribution of EAPP to the development of aneuploid tumor cells.

Main Methods:

  • Analysis of EAPP protein levels in human tumors.
  • Investigating the effect of EAPP overexpression on G1 arrest and apoptosis.
  • Assessing EAPP's interaction with the p21 promoter and its transcriptional activity.
  • Examining the impact of EAPP on Chk2 phosphorylation and activity.

Main Results:

  • EAPP overexpression leads to G1 arrest and impaired apoptosis in a p21-dependent manner.
  • EAPP binds to and stimulates the p21 promoter, suggesting a role in transcription initiation.
  • EAPP regulates the phosphorylation status of Chk2, leading to its dephosphorylation and inactivation.
  • EAPP overexpression may affect the newly identified role of Chk2 in mitosis, potentially contributing to aneuploidy in tumor cells.

Conclusions:

  • EAPP is a key regulator of cellular homeostasis and DNA damage response.
  • EAPP's modulation of p21 and Chk2 activity has significant implications for cell fate decisions and genomic stability.
  • The findings suggest EAPP's overexpression contributes to cancer development by disrupting critical cell cycle control mechanisms.

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