Math models morphogenesis and mitosis

When a budding yeast cell is unable to form a new bud, cell division pauses in G2 phase, either until a bud can grow or until the cell “adapts” to the situation by becoming dinucleate. Ciliberto et al. collected the available experimental data on this morphogenesis checkpoint, and on page 1243 they present a mathematical model that explains previous results and makes some surprising predictions.

The morphogenesis checkpoint relies on antagonism between the Swe1 kinase, which inhibits entry into mitosis, and the active form of the Cdc28–Clb2 cyclin complex, which promotes it. In the model, a set of differential equations accounts for the phenotypes of a dozen morphogenesis checkpoint mutants by incorporating a few initial assumptions. Although previous work showed that Hsl1 kinase flags Swe1 for degradation, the mathematical model demonstrates that Hsl1...