Figure 1.

The spindle assembly checkpoint and cell fate. During mitosis, the constitutively active spindle assembly checkpoint (SAC) delays anaphase until all chromosomes are attached to the mitotic spindle. Any stress that prevents satisfaction of the SAC results in a prolonged mitotic arrest, which often leads to cell death. However, the SAC can be over-come by the release of Cdc20 from the mitotic checkpoint complex (MCC) or by direct inhibition of Cdk1. This mitotic slippage can result in polyploidy, increased cell survival, and provides a potential mechanism for escaping mitotic cell death.