When yeast cells change their mind: cell cycle "Start" is reversible under starvation
Deniz Irvali1, Fabian P Schlottmann1, Prathibha Muralidhara1
1Interfaculty Institute of Cell Biology, University of Tuebingen, Tuebingen, Germany.
The EMBO Journal
|November 24, 2022
Summary
Yeast cells can reverse their cell division commitment after passing the Start point if nutrients are depleted. The cell cycle inhibitor Whi5 is re-imported into the nucleus, pausing division until nutrients are restored.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Eukaryotic cells commit to division at the Restriction Point (mammals) or Start (yeast) in late G1.
- Yeast cells integrate signals at Start, halting progression if nutrients are scarce.
- Post-Start responses to nutrient depletion remain unclear.
Purpose of the Study:
- Investigate how yeast cells respond to nutrient depletion after passing the Start point.
- Analyze the role of Whi5, a cell cycle inhibitor, in this process.
Main Methods:
- Monitoring Whi5 localization in post-Start yeast cells under nutrient depletion.
- Assessing cell cycle progression and re-entry dynamics.
Main Results:
- Post-Start yeast cells can re-import the Whi5 inhibitor into the nucleus.
- Re-importation interrupts the G1/S transcription feedback loop and re-sensitizes cells to pheromones.
- CDK activation can re-occur upon nutrient replenishment, indicating a reversible commitment.
Conclusions:
- Nutrient starvation can reverse the cell cycle commitment decision at Start in yeast.
- Cell cycle commitment is a multi-step process, potentially conserved across eukaryotes.
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