Stochastic resonance for adhesion of membranes with active stickers.

The behavior of two membranes that interact by active adhesion molecules or stickers is studied theoretically using mean-field theory and Monte Carlo simulations. The stickers are anchored in one of the membranes and undergo conformational transitions between on and off states. In their on states, the stickers can bind to ligands that are anchored in the other membrane. The transitions between the on and off states arise from the coupling of the stickers to some active, energy-releasing process, which keeps the system out of equilibrium. As one varies the transition rates of this active process, the membrane separation undergoes a stochastic resonance: this separation is maximal at intermediate rates of the sticker transitions and considerably smaller both at high and at low transition rates. This implies that the effective, fluctuation-induced repulsion between the membranes contains a rate-dependent contribution that arises from the switching of the active stickers.