Contraction and Connectivity in Simulated Cytoskeletal Networks

The structure and mechanics of cytoskeletal networks are fundamental to cell morphology, migration and division. In this work, we develop methods to quantify the connectivity of fiber-motor networks and identify geometrical conditions that ensure network contraction through a mechanism known as polarity sorting. We then derived, for such conditions, a theory that quantitatively predicts the rate of network contraction as a function of its connectivity and biochemical and physical parameters such as motor speed, binding rates, filament lengths and medium viscosity. Predictions are tested using the physics simulator CytoSim. Lastly we discuss how those outcomes are affected by the introduction of crosslinking proteins, which can increase connectivity but frustrate the contraction mechanisms.