Current Biology
Volume 28, Issue 1, 8 January 2018, Pages 28-37.e7
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Article
Cells Escape an Operational Mitotic Checkpoint through a Stochastic Process

https://doi.org/10.1016/j.cub.2017.11.031Get rights and content
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Highlights

  • Yeast cells under nocodazole arrest adapt in the presence of an active SAC

  • Adaptation dynamics can be described as a stochastic process

  • All cells in the population share the same propensity to adapt

  • Increasing Cdc20 levels favors adaptation but does not impair the SAC

Summary

Improperly attached chromosomes activate the mitotic checkpoint that arrests cell division before anaphase. Cells can maintain an arrest for several hours but eventually will resume proliferation, a process we refer to as adaptation. Whether adapting cells bypass an active block or whether the block has to be removed to resume proliferation is not clear. Likewise, it is not known whether all cells of a genetically homogeneous population are equally capable to adapt. Here, we show that the mitotic checkpoint is operational when yeast cells adapt and that each cell has the same propensity to adapt. Our results are consistent with a model of the mitotic checkpoint where adaptation is driven by random fluctuations of APC/CCdc20, the molecular species inhibited by the checkpoint. Our data provide a quantitative framework for understanding how cells overcome a constant stimulus that halts cell cycle progression.

Keywords

mitotic checkpoint
spindle assembly checkpoint
adaptation
molecular network dynamics
mathematical models

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These authors contributed equally

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