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A morphogenesis checkpoint monitors the actin cytoskeleton in yeast
J N McMillan1, R A Sia, D J Lew
1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
The Journal of Cell Biology
|September 23, 1998
Summary
Budding yeast employ a morphogenesis checkpoint to delay cell cycle progression when actin organization is perturbed. This checkpoint, dependent on Swe1p, monitors actin directly and responds during a specific cell cycle window.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Budding yeast possess a morphogenesis checkpoint that halts cell cycle progression.
- This checkpoint responds to disruptions in cell polarity that impede bud formation.
- The checkpoint relies on the tyrosine kinase Swe1p to inhibit the cyclin-dependent kinase Cdc28p.
Purpose of the Study:
- To investigate the specific defects that activate the morphogenesis checkpoint.
- To determine if actin cytoskeleton integrity is the direct trigger for the checkpoint.
Main Methods:
- Perturbation of the actin cytoskeleton in budding yeast.
- Analysis of cell cycle progression in response to actin perturbations.
- Monitoring Swe1p levels throughout the cell cycle.
Main Results:
- Direct actin cytoskeleton perturbations trigger a Swe1p-dependent cell cycle delay, independent of polarity establishment.
- The checkpoint can be activated even after bud formation, indicating a focus on actin organization.
- The checkpoint detects actin perturbations throughout most of the cell cycle.
- Cell cycle delay response is restricted to a specific phase, coinciding with Swe1p accumulation.
Conclusions:
- The morphogenesis checkpoint in budding yeast directly monitors actin organization.
- The timing of the cell cycle delay is regulated by the periodic availability of the effector Swe1p.