Fig. 4

Experiments agree with the optimal control theory predictions. a Representative immunofluorescence images showing the dynamics of (top) nephrin localization in podocytes, and (bottom) vimentin localization in fibroblasts. Cells were plated on channel or rhombus micropatterns, treated with integrin β₃ blocking antibodies or blebbistatin, fixed at given time points, and stained for nephrin or vimentin (green) as well as F-actin (red). b Experimentally measured localization dynamics in podocyte and fibroblasts for (i) nephrin (podocytes) and (ii) vimentin (fibroblasts) were fitted with the temporal order predicted from the optimal control solution (blue and red lines). Both cells show an excellent fit with the control models. A clear shape-tension transition is revealed which confirm the predicted strategy that cells initially respond to shape signals followed by a transition to a tension-driven mechanism. (iii) The localization ratio between shape and tension signals reveals how well the predicted switching time, t agrees with the measured dynamics. Experimental values are given as mean ± SEM; n = 20 cells per timepoint, chosen from four different slides, cultured independently