SPRTN protease and checkpoint kinase 1 cross-activation loop safeguards DNA replication

Area of Science:

• Molecular Biology
• Cellular Biology
• Genetics

Background:

• SPRTN metalloprotease is vital for DNA repair and replication.
• SPRTN deficiency leads to replication stress, genome instability, premature aging, and cancer.

Purpose of the Study:

• To elucidate the mechanism by which SPRTN activates the ATR-CHK1 signaling cascade during DNA replication.
• To investigate the role of SPRTN-CHK1 interaction in maintaining genome stability.

Main Methods:

• Proteolysis assays
• Chromatin immunoprecipitation
• Western blotting
• Analysis of purified components

Main Results:

• SPRTN activates ATR-CHK1 signaling by proteolytically evicting CHK1 from chromatin.
• SPRTN cleaves CHK1, releasing active N-terminal kinase fragments.
• CHK1 phosphorylates SPRTN, enhancing its chromatin recruitment for DNA replication and DPC repair.
• A SPRTN-CHK1 cross-activation loop is identified, crucial for DNA replication and stress protection.

Conclusions:

• A novel SPRTN-CHK1 cross-activation loop is essential for DNA replication and protection against replication stress.
• This loop contributes to maintaining genome integrity and preventing age-related diseases and cancer.