Figure 5.

Mathematical modeling of a robust PleC/DivJ switch. (a) Steady state analysis of DivK and DivK~P. The curves show that PleC/DivJ regulation forms a sensitive switch to convert DivK and DivK~P concentration to two distinctly different stable states; (b) and (c) are heat maps of DivK~P concentration level with PleC/DivJ regulation. Crosses represent wild type of swarmer cells (lower-right) and stalked cells (upper-left). Circles shows the cells with spatial perturbations. The solid lines indicates the arbitrary threshold that separate swarmer cell and stalked cell based on the concentration level of DivK~P; (b) Represents that PleC is recruited to the stalked cell; and (c) Shows DivJ is recruited to the swarmer cell. Heatmaps show that DivK~P levels in both of stalked and swarmer cells are changed with spatial perturbations, but the cell fates are not converted without strong enough effects; (d) The ratio of fluorescent intensity of recombinant DivJ and PleC between stalked cells and swarmer cells. In strain PB021 (PleC-GBDpep-CFP, DivK-SH3pep-YFP, mCherry-SH3(8)-GBD), the average ratio of mis-localized PleC in stalked cells and correctly localized PleC in swarmer cells was 0.55:1, SEM = 0.05. In strain PB025 (DivJ-GBDpep-CFP, DivK-SH3pep-YFP, mCherry-SH3(8)-GBD), the average ratio of correctly localized DivJ in stalked cells to mis-localized DivJ in swarmer cells was 2.2:1, SEM = 0.22.