Perfect Stabilization of Biomolecular Adhesions under Load

Abstract: Cells attach to their environment by means of focal adhesions, which are molecular complexes that exhibit the remarkable ability to adapt to mechanical load by changing their size. Drawing from the biomolecular mechanisms underlying this behavior, we present a generic model for mechanically induced adhesion growth where conformational states of molecules already in the adhesion cluster are coupled to the adsorption of further molecules. For sufficiently strong coupling, an instability arises and unbounded system growth ensues in the absence of mechanical load. Unexpectedly, the same type of instability can lead to perfect stability under mechanical load, whereby adhesion clusters adjust their size to withstand arbitrarily large forces without breaking, a phenomenon we term perfect stabilization. We derive state diagrams that characterize adhesion stability under stationary loads and show that perfect stabilization also occurs under dynamic loading on physiologically relevant timescales. Finally, we show that perfect stabilization and related instabilities are generic phenomenona that can be realized in many different ways if internal molecule states are coupled to adsorption in nonequilibrium.