A strong nonequilibrium bound for sorting of cross-linkers on growing biopolymers
Yuqing Qiu, Michael Nguyen, Glen M. Hocky, Aaron R. Dinner, Suriyanarayanan Vaikuntanathan · Proceedings of the National Academy of Sciences · 2021
Significance Understanding the connection between microscopic driving forces in biological systems and their emergent structures remains an outstanding challenge. We tackle this problem by deriving a fluctuation–response bound in the context of actin polymerization and bundling and verify its robustness far from equilibrium through simulation. Our results show how actin polymerization, molecular fluxes of cross-linker binding, and the morphology of the growing bundle are associated quantitatively; when the bound is saturated, it becomes a nonequilibrium linear-response relation. Molecular driving forces are difficult to measure directly in biological systems, and this work represents a first step toward estimating them from experimentally accessible quantities such as molecular fluxes and compositions.