lncreased risk of slippage upon disengagement of the mitotic checkpoint
Fig 4
Dynamics of nocodazole washout in APC-A mutants.
A) Bifurcation diagrams showing the effect of decreasing APC/CCdc20 binding to 88%, 79% and 69% of Wild Type levels. Wild type in black. Equations in S1 Text, and parameters in Table 2. B) Adapting vs exiting cells. Left panel: APC-A cells growing in YPRG were arrested in G1 and released in nocodazole for 180 minutes, after which nocodazole was removed from the media. Cells carry Mad2-GFP to record mitotic checkpoint activation, and Clb2-mCherry to record mitotic exit (Clb2 degradation time). Adaptation and exit are defined based on Mad2 localization at Clb2 degradation time (see S2B Fig). Only cells degrading completely Clb2 are included in the percentage (see S2A Fig). Right panel: same percentages for the simulated data, where adaptation is defined as APC/C reaching the activation threshold with at least one unattached kinetochore. Reactions in Table 3, parameters in Table 2, initial conditions in Table 1 (checkpoint ON). At time 0, kinetochore attachment is allowed. C) Different dynamics of cells exiting and adapting. Upper panel: histograms of APC/C activation time in in cells adapting (purple) or exiting properly (green). Simulations details as in panel (B) right. Lower panel: histograms of Clb2 degradation time in in cells adapting (purple) or exiting (green). Experimental details as in (B) left. D) Comparison of Clb2 degradation time (experiments) and APC/C activation (simulations) in wild-type and APC-A cells. Left, experimental data: cells are the same presented in the barplots in Figs 3A and 4B. Right, results from wash-out simulations. Equations in S1 Text, and parameters in Table 2.