Abstract
The cell division cycle is not an autonomous oscillator, like a circadian rhythm, but rather a circular sequence of events that must be carried out in a specific order. The order of events is enforced by checkpoints that control progression from one stage of the cell cycle to the next. The transitions can be made only if the prior event is properly accomplished. Cell cycle transitions are irreversible (ratchet-like) because they are implemented by bistable switches in the dynamics of the underlying molecular regulatory network. In this chapter we show how bistability and irreversibility are emergent properties of molecular interactions, how bistability ensures unidirectional progression around the cell cycle, and how checkpoint mechanisms use bistable switching networks to maintain genomic integrity. While emphasizing generic properties of these controls in all types of eukaryotes, we also discuss some characteristic differences between yeast cells and mammalian cells.
Users
Please
log in to take part in the discussion (add own reviews or comments).
