Figure 6.

Influence of clutch reinforcement on traction force and optimal substrate stiffness. Force transmission on rigid substrates results from a competition between load-dependent clutch reinforcement and myosin-mediated clutch loading rates. (A and B) Dimensionless time-averaged traction force as a function of substrate stiffness for different values of the clutch reinforcement parameter $\theta$ and clutch reinforcement threshold force $\Delta$. Parameter values: $\tau =1$, $\omega =200$, (A) $\mathrm{F}=1$ and (B) $\mathrm{F}=10$. (C) Dimensionless time-averaged traction force on rigid substrates ($\mathrm{K}\to \infty$) as a function of $\Delta$ for four different values of the unloaded velocity parameter $\omega$. Parameter values: $\theta =10,\mathrm{F}=1,\tau =5$. (D) Optimum substrate stiffness as a function of $\theta$ for different values of $\Delta$. Parameter values: $\omega =200,\mathrm{F}=1,\tau =1$. Solid lines are the numerical solution of the developed mean-field model (Eq. 7), and symbols are the numerical solutions of the stochastic motor-clutch model. To see this figure in color, go online.