Extended Data Fig. 5: The role of myosin II density in the mechanosensitive cell adhesion behaviour.

(a, b) Fitting of experimental data collected on MEF Talin 1 KO, Talin 2 shRNA cells (a) and MEF WT cells (b) treated with different concentrations of the myosin II inhibitor, blebbistatin [13]. The data were fitted to the linear KD model [solid curves, panel (a)], linear WT model [solid curves, panel (b)] and talin WT model [dotted curves, panel (b)], respectively, by varying only the density of myosin II motors. The remaining model parameters were fixed at the values shown in Table T1, SI. The dashed segments of the cell traction curves in panel (a) indicate unstable branches of the corresponding graphs. Panels (a, b) show that while MEF Talin 1 KO, Talin 2 shRNA cells are predicted to have bistable behaviour on rigid substrates at low myosin II densities, MEF WT cells lack this type of behaviour due to the high elasticity of talin-based molecular clutches, see Fig. 5 in the main text for additional details.