State-dependent recruitment of adhesion molecules enables perfect stabilization in cell-adhesion models

Abstract

Cells adapt their adhesion to mechanical load, but the physical conditions under which this response prevents rupture remain unclear. Inspired by focal adhesions, we study models in which force-sensitive conformational states within an adhesion cluster are coupled to the recruitment of additional molecules. We show that sufficiently strong coupling creates a distinct regime under load in which clusters grow in proportion to the applied force while the average load per bond remains below the level that destabilizes the cluster. The clusters can therefore withstand arbitrarily large stationary forces in principle. We term this behavior ``perfect stabilization''. At still stronger coupling, the same feedback causes unbounded growth already at equilibrium. For the minimal model, we derive state diagrams that characterize adhesion stability under stationary and dynamic loading. More broadly, using generic molecular-state networks, we derive conditions under which perfect stabilization and related growth instabilities arise in nonequilibrium adhesion systems with state-dependent recruitment.