Mathematics Colloquia and Seminars

Return to Colloquia & Seminar listing

Muscle contraction is a fundamental biological process that drives essential processes from heart function to locomotion. At the smallest scale, contraction is a result of interactions between two proteins, actin and myosin. These molecular measurements are well-described by a four-state mechanochemical model which includes two “bound” states, where myosin is bound to actin and producing force, and two “unbound” states, where myosin and actin do not interact. Larger scale fiber level measurements, however, suggest the existence of an additional weakly-bound interaction between actin and myosin. In this work, we examine two mathematical models to understand the effect of weak binding. We find that both a weakly-bound interaction between actin and myosin, as well as nonlinear elasticity of myosin, are necessary to consistently model muscle measurements from the molecular to cellular levels, and that weak-binding is acting as a viscous drag.