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Updated: Sep 26, 2026

Manipulation and Analysis of Cell Cycle-Dependent Processes in Budding Yeast
08:13

Manipulation and Analysis of Cell Cycle-Dependent Processes in Budding Yeast

Published on: September 26, 2025

Budding yeast PAK kinases regulate mitotic exit by two different mechanisms

Elena Chiroli1, Roberta Fraschini, Alessia Beretta

  • 1Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.

The Journal of Cell Biology
|March 19, 2003
PubMed

Insights

The dominant-negative CLA4t allele in budding yeast inhibits cell division by delaying anaphase onset and mitotic exit. This involves the p21-activated kinase (PAK) family and affects key cell cycle regulators.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • The CLA4 gene encodes a p21-activated kinase (PAK) family member essential for budding and cytokinesis in yeast.
  • PAK kinases, including Cla4 and Ste20, play critical roles in regulating cell division processes.

Purpose of the Study:

  • To characterize the dominant-negative CLA4t allele of the budding yeast CLA4 gene.
  • To investigate the role of Cla4 and Ste20 in cell cycle progression, specifically anaphase onset and mitotic exit.

Main Methods:

  • Characterization of the dominant-negative CLA4t allele.
  • Analysis of cell cycle progression delays and protein degradation.
  • Investigation of the involvement of Swe1 and Tem1 in Cla4t-mediated effects.

Main Results:

  • Overproduction of Cla4t inhibits endogenous Cla4 and Ste20, delaying anaphase onset.
  • Cla4t inactivates Cdc20/anaphase-promoting complex (APC)-dependent proteolysis of cyclin B and securin.
  • Cla4t-dependent cell cycle delay requires Swe1, impacting mitotic exit network (MEN) activation.
  • Cla4t also inhibits mitotic exit via a Swe1-independent pathway affecting Tem1.

Conclusions:

  • Cla4 and Ste20 likely regulate the initial cyclin B proteolysis mediated by Cdc20/APC, crucial for MEN activation.
  • Cla4t disrupts cell cycle progression through both Swe1-dependent and independent mechanisms, impacting MEN activation.
  • PAK kinases are key regulators of both budding/cytokinesis and mitotic exit in yeast.

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