The Polo-like kinase Cdc5 interacts with FEAR network components and Cdc14

Area of Science:

• Cell Biology
• Molecular Biology
• Yeast Genetics

Background:

• Mitotic exit in Saccharomyces cerevisiae is controlled by the phosphatase Cdc14.
• Cdc14 is inhibited and sequestered in the nucleolus by Cfi1/Net1 during interphase and early mitosis.
• The FEAR and MEN pathways coordinate Cdc14 release from the nucleolus during anaphase.

Purpose of the Study:

• To investigate the physical interactions of the FEAR network component Cdc5 with other proteins involved in Cdc14 regulation.
• To elucidate the mechanism by which Cdc5 influences Cdc14 localization and activation during mitotic exit.

Main Methods:

• Co-immunoprecipitation assays to detect physical associations between proteins.
• Analysis of protein-binding domains, specifically the Polo-box domain of Cdc5.
• In vivo studies to confirm direct interactions and functional relevance.

Main Results:

• Cdc5 physically associates with Separase Esp1 and the Esp1-binding protein Slk19.
• Cdc5 directly interacts with Cdc14.
• The Polo-box domain of Cdc5 mediates the interaction with Cdc14, suggesting a role in recognizing phosphorylated substrates.

Conclusions:

• Cdc5 plays a central role in the localization and regulation of Cdc14 during mitotic exit.
• The direct physical association between Cdc5 and Cdc14 provides a mechanistic link for Cdc14 release and activation.
• Understanding these interactions is crucial for comprehending cell cycle control in yeast.