FIGURE 4:

Stronger mutual coupling between the actin networks and the signaling system improves cell polarization. Twenty simulations are considered for each set of parameters. Based on the outcome, the probability of a stable polarized solution is reported as the fraction of polarized solutions out of the total number of simulations for that specific choice of parameters. (a) Polarization probability is reported as a function of the two coupling parameters in the mechanochemical positive feedback loop, α and β. The parameters that were used to produce the simulations shown in Figure 3 are indicated. (b) Polarization probability as a function of two signaling kinetic rates: induced recruitment to the membrane rate k_fb and disassociation rate k_off. (c) Polarization probability as a function of two signaling kinetic rates: spontaneous association rate k_on and disassociation rate k_off. For subplots (a–c), a strongly coupled system is considered with α = β = 2. Effect of the actin competition parameter m₀ on polarization probability is reported for (d) a weakly coupled system, α = β = 0.2, and (e) a strongly coupled system, α = β = 2.