(127i) Relating Energy Dissipation to Effective Interactions and Structure Formation in Cross-Linked Biopolymer with Molecular Motors

Active biological systems such as the actin networks in cytoskeleton exhibit a wide range of interaction types and are subject to a variety of external stimuli. In this work, we aim to identify the metrics that govern the formation and stability of structures in the cytoskeleton. Previous work on non-equilibrium liquids [Tociu et al. PRX 2018] demonstrated that their structure and dynamics can be altered by changing the rate at which the system dissipates energy. We extrapolate this concept to cross-linked biopolymer networks driven by molecular motors. Using simulations of the cytoskeletal networks and cloning algorithm, we sample large-deviation biased ensembles of actomyosin networks and find a connection between their pattern formation and thermodynamic quantities such as energy dissipation. We consider a system in which molecular motors mediate effective interactions between actin filaments, and drive the formation of either actin asters or bundles depending on the rigidity of motors. We investigate the nature of the transition between asters and bundles, and demonstrate that biasing the rate of energy dissipation in a system with fixed motor rigidity has the same effect on structure modulation as tuning the motor rigidity. This work elucidates the relationship between energy dissipation, effective interactions, and pattern formation in active biopolymer network, which would lead to improved understanding of underlying principles that control the cytoskeletal structure and dynamics.