Extended Data Fig. 2: Experimental data fitting to a model describing the competitive formation of two types of molecular clutches (WT-2 model). | Nature Physics

Extended Data Fig. 2: Experimental data fitting to a model describing the competitive formation of two types of molecular clutches (WT-2 model).

From: Elastic properties of force-transmitting linkages determine multistable mechanosensitive behaviour of cell adhesion

Extended Data Fig. 2: Experimental data fitting to a model describing the competitive formation of two types of molecular clutches (WT-2 model).The alternative text for this image may have been generated using AI.

(a, b) Fitting of the cell traction and retrograde actin flow experimental data from refs. 13,21 collected on MEF WT cells (red circles) and MEF Talin 1 KO, Talin 2 shRNA cells (green triangles) to the WT-2 model describing the competitive formation of two types of molecular clutches: 1) soft, nonlinear, talin-dominant one, prevalent in WT cells, and 2) more rigid, linear, non-talin-based one, prevalent in talin-deficient cells. The WT-2 model fits experimental data obtained in MEF WT cells more accurately [red curves in panels (a, b)] compared to the linear WT and talin WT models [Fig. 2(c,d) in the main text], with most of the model fitting parameters being similar to those in the linear KD and talin WT models, see Tables T1 and T2, SI. Moreover, the WT-2 model predicts that even 10% of the maximum density of talin in FAs, and hence 10% of the rate of talin-based molecular clutch formation (\({k}_{{\rm{on}}}^{0}\)), is sufficient to stabilize cell adhesion to rigid substrates (E > 10 kPa), but not to soft substrates (5 kPa < E < 10 kPa), see the blue curves in panels (a, b). (c) Negative correlation between cell traction and retrograde actin flow. Existing experimental data and models tested in this study show a negative linear correlation between cell traction and retrograde actin flow, which arises from the linear force-velocity relationship of myosin II motors, see panel (d) and Appendix H, SI for details. (d) Schematic explanation of the graphs shown in panel (c). The physicochemical properties of molecular clutches do not affect the correlation between experimentally measured cell traction and retrograde actin flow, since stable stationary points, which represent the steady-state of the molecular clutch system, correspond to the intersection points of the cell traction force curve, Fc(v), and the myosin II force-velocity curve, Fm(v). Thus, these points always lie on the linear force-velocity curve of myosin II motors, resulting in a linear correlation between experimentally measured cell traction and retrograde actin flow.

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