The ATM-E6AP-MASTL axis mediates DNA damage checkpoint recovery

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Cell cycle arrest following DNA damage is crucial for genomic stability.
• The mechanisms initiating cell cycle recovery after DNA damage are not fully understood.

Purpose of the Study:

• To elucidate the molecular mechanisms governing cell cycle recovery after DNA damage.
• To identify key regulators involved in the transient nature of the DNA damage checkpoint.

Main Methods:

• Western blotting to assess protein levels.
• Ubiquitination assays to study protein degradation.
• Immunoprecipitation to investigate protein interactions.
• Cell cycle analysis to monitor progression.

Main Results:

• MASTL kinase levels increase after DNA damage due to decreased protein degradation.
• E3 ubiquitin ligase E6AP mediates MASTL degradation, and its dissociation from MASTL upon DNA damage stabilizes MASTL.
• ATM-dependent phosphorylation of E6AP at Ser-218 is required for MASTL stabilization and cell cycle recovery.
• Depletion of E6AP promotes cell cycle recovery in a MASTL-dependent manner.

Conclusions:

• ATM/ATR signaling activates the DNA damage checkpoint and simultaneously initiates cell cycle recovery.
• The ATM/ATR-MASTL-E6AP axis acts as a timer, ensuring the transient nature of the DNA damage checkpoint.