FIG 4.

Effect of KinC on the heterogeneity of Spo0A∼P levels in individual cells. (A) KinC reduces the heterogeneity of Spo0A levels in individual cells. In fast-growing cells, KinA levels are low, so KinC induces intermediate Spo0A∼P levels. In slow-growing cells, KinA accumulates and induces high levels of Spo0A∼P, while KinC reduces Spo0A∼P levels. (B) A higher mean Spo0A∼P level does not guarantee a higher mean PtapA activity. For a toy model, we assume that the Spo0A∼P levels in WT and ΔkinC strains follow normal distributions. The mean and variance of Spo0A∼P level are both higher in the ΔkinC strain. The gray area indicates the fraction of cells not expressing tapA. The dashed line shows the threshold level of Spo0A∼P to activate tapA. (C) Predicted distribution of Spo0A∼P level in ΔkinC and WT strains. The solid and dashed lines corresponding to the right y axis show how activities of PspoIIG and PtapA, respectively, depend on Spo0A∼P level. (D and E) Predicted distributions of PtapA (D) and PspoIIG (E) activity in ΔkinC and WT strains.