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Chk1 modulates the interaction between myosin phosphatase targeting protein 1 (MYPT1) and protein phosphatase 1cβ

Xiaomei Hu1, Zhe Li1, Yuehe Ding2

  • 1a Beijing Key Laboratory of DNA Damage Response and College of Life Sciences , Capital Normal University , Beijing 100048 , China.

Cell Cycle (Georgetown, Tex.)
|December 22, 2017
PubMed

Insights

The DNA damage response inactivates Polo-like kinase 1 (Plk1) via Chk1-mediated phosphorylation of MYPT1. This mechanism recruits protein phosphatase 1β (PP1cβ) to dephosphorylate and inhibit Plk1 during mitotic damage.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Polo-like kinase 1 (Plk1) is crucial for cell cycle regulation.
  • Plk1 activity is targeted during DNA damage response, but the precise mechanism is unclear.
  • Previous studies link Plk1 inhibition to ATM/ATR and Chk1 pathways.

Purpose of the Study:

  • To elucidate the mechanism by which Chk1 regulates Plk1 activity during DNA damage.
  • To identify proteins interacting with Chk1 in the context of DNA damage response.

Main Methods:

  • Proteomic screening to identify Chk1-interacting proteins.
  • Immunoprecipitation assays.
  • Phosphorylation site analysis (Ser20).
  • Assays to measure Plk1 activity and MYPT1 degradation.

Main Results:

  • Myosin phosphatase targeting protein 1 (MYPT1) was identified as a Chk1-interacting protein.
  • Chk1 directly phosphorylates MYPT1 at Ser20, which is critical for recruiting protein phosphatase 1β (PP1cβ).
  • This Chk1-mediated phosphorylation of MYPT1 leads to Plk1 dephosphorylation and inactivation.
  • Chk1 phosphorylation also regulates MYPT1 degradation.

Conclusions:

  • Chk1-induced phosphorylation of MYPT1 is a key mechanism for attenuating Plk1 activity during mitotic damage.
  • This pathway involves the recruitment of PP1cβ to dephosphorylate Plk1.
  • The findings reveal a novel regulatory axis controlling Plk1 during cellular stress.
Keywords:
Cell cycleDNA damageMYPT1PP1cβPlk1mitosis

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