Model parameters for an AC with α5β1 and αVβ3 integrins.

For Young’s modulus of the substrate, we take again the range E = 0.1–100 kPa. For the radius of the FA, we take a fixed value of a = 708 nm [50] with equispaced ligands at a distance of d = 100 nm. The number of equispaced ligands nc is then computed given the radius of the circular AC and the distance d, and we get nc = 158 binders (see Fig A5 in S1 Text). For the stiffness of the linear spring that models the integrin, we take κc = 10 pN/nm [40, 73]. For the initial density of integrins, we choose int/μm2 [8, 69]. The stall force of a single myosin motor is Fm = 2 pN [78] and we take several myosin motors equal to the number of ligands, following previous models [43, 69]. As for the unloaded actin velocity vu, we choose vu = 110 nm/s, similar to velocities measured in previous experimental data [79–81].