Human CDK18 promotes replication stress signaling and genome stability

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Cyclin-dependent kinases (CDKs) are crucial for cell cycle control and DNA repair, maintaining genome stability.
• Genome instability arises from various complex mechanisms that are not fully understood.

Purpose of the Study:

• To identify novel regulators of genome stability.
• To elucidate the role of CDK18 (PCTAIRE 3) in maintaining genome integrity.

Main Methods:

• Depletion of CDK18 using specific techniques.
• Analysis of DNA damage and chromosomal abnormalities.
• Assessment of cell cycle progression and replication fork kinetics.
• Investigation of ATR kinase signaling pathways.
• Co-immunoprecipitation assays to identify interacting proteins.
• Chromatin retention assays for RAD17 and RAD9.
• Rescue experiments using exogenous CDK18.

Main Results:

• CDK18 depletion leads to increased endogenous DNA damage and chromosomal abnormalities.
• Cells lacking CDK18 arrest in early S-phase with slowed replication fork progression.
• Replication stress response is impaired, with reduced ATR kinase signaling.
• CDK18 interacts with RAD9, RAD17, and TOPBP1.
• CDK18 deficiency reduces RAD17 and RAD9 chromatin retention under replication stress.
• Phenotypes are rescued by kinase-dependent expression of CDK18.

Conclusions:

• CDK18 plays a critical, rate-limiting role in replication stress signaling.
• CDK18 is established as a novel regulator of genome integrity.
• Understanding CDK18's function offers new insights into maintaining genomic stability.