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Protein phosphatase 5 regulates the function of 53BP1 after neocarzinostatin-induced DNA damage

Yoonsung Kang1, Jung-Hee Lee, Nguyen Ngoc Hoan

  • 1Departments of Pharmacology, Bio-materials, Orthopedic Surgery, and Anatomy, Chosun University, 375 Seosuk-dong, Gwangju 501-759, Korea.

The Journal of Biological Chemistry
|January 30, 2009
PubMed

Insights

Protein phosphatase 5 (PP5) regulates DNA repair protein 53BP1 (p53-binding protein 1) phosphorylation and activity. PP5 accelerates 53BP1 dephosphorylation, impacting DNA double-strand break repair efficiency.

Area of Science:

  • Molecular Biology
  • DNA Repair Mechanisms
  • Cellular Signaling

Background:

  • 53BP1 (p53-binding protein 1) is crucial for DNA double-strand break repair.
  • Understanding 53BP1 regulation is key to elucidating DNA damage response pathways.

Purpose of the Study:

  • To identify novel 53BP1-interacting proteins using a yeast two-hybrid system.
  • To characterize the functional interaction between 53BP1 and protein phosphatase 5 (PP5).

Main Methods:

  • Yeast two-hybrid screening to identify interacting partners.
  • Cell-based assays in U2OS cells with neocarzinostatin (NCS) treatment.
  • Western blotting to assess protein phosphorylation and dephosphorylation.
  • Analysis of phospho-53BP1 foci formation and non-homologous end-joining activity.

Main Results:

  • Protein phosphatase 5 (PP5) was identified as a 53BP1-binding protein.
  • PP5 overexpression accelerated 53BP1 dephosphorylation at Ser-25 and Ser-1778 after NCS treatment.
  • PP5 down-regulation inhibited 53BP1 dephosphorylation and phospho-53BP1 foci disappearance.
  • PP5 overexpression reduced non-homologous end-joining activity.

Conclusions:

  • PP5 plays a significant role in regulating 53BP1 phosphorylation and activity in vivo.
  • The interaction between PP5 and 53BP1 impacts DNA double-strand break repair processes.

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