Figure 5
From: Distinct predictive performance of Rac1 and Cdc42 in cell migration
Models of cell migration.
(a) A model of signal transmission from Rho GTPases to edge displacement in order to explain Rho GTPases activation following membrane protrusion. The response function (middle panel) processes an input signal (Rac1/Cdc42 in the left panel) and generates an output (edge displacement in the right panel). The red and blue curves in the middle panel correspond to the response functions with leaky and differentiating properties, respectively. Note that the estimated response functions possess the differentiating property (right inset in Fig. 2d). In the right panel, output signal through the response function with differentiating property indicated by the red line is followed by input signal, which is plotted by the thin black curve for comparison. (b) A model of migration modes depending on the balance between the activities of Rac1 and Cdc42. In persistently and randomly migrating cells, Rac1 and Cdc42 have great contributions to the cell migration, respectively, which can be evaluated in terms of the predictability measure (Fig. 3c). (c) A tug-of-war model of macroscopic cell migration. The angle and speed of the cellular migration indicated by the red vector can be predicted by summation like tug-of-war of the distributed driving factors of the locally extended membrane indicated by the black arrows (Fig. 4). The driving factors are predicted by Rac1/Cdc42 through the response function (Fig. 2a).
