Mitotic Exit Function of Polo-like Kinase Cdc5 Is Dependent on Sequential Activation by Cdk1

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Mitotic exit in Saccharomyces cerevisiae requires Cdc14 activation.
• Two pathways, FEAR and MEN, regulate Cdc14.
• The precise role of Cdc5 polo-like kinase in Cdc14 release is unclear.

Purpose of the Study:

• To elucidate the mechanism by which Cdc5 contributes to timely Cdc14 release.
• To investigate the specific role of Cdc5 in mitotic exit regulation.

Main Methods:

• Genetic analysis
• Biochemical assays
• Phosphorylation studies

Main Results:

• Cdc5 functions in parallel with the MEN pathway during anaphase.
• Cdc5's MEN-independent function requires active separase.
• Cdk1-dependent phosphorylation activates Cdc5 in early anaphase and promotes its MEN-related functions in late anaphase.

Conclusions:

• Cdc5 is a key regulator of Cdc14 release, acting both independently and in conjunction with the MEN pathway.
• Cdk1-mediated phosphorylation is crucial for Cdc5 activation and function in mitotic exit.