(604f) Self-Organization of Molecular Motors in Biopolymer Droplets

Soft, active materials self-organize from macromolecules in cells to form precisely structured assemblies that orchestrate specific biological functions. Critical to understanding biological assemblies and informing bio-inspired soft materials design is understanding the mechanisms regulating this spatial self-organization. Using a model system of a biopolymer liquid crystal that we recently developed, we investigate mechanisms of self-organization driven by anisotropy. From a minimal set of purified proteins derived from the cellular cytoskeleton, we form unusual cross-linked liquid crystal droplets, composed of biopolymer filaments, that have tunable shape and material properties. We find that enzymatically active motor proteins, which form assemblies that bind to and translocate biopolymer filaments, spatially self-organize in these biopolymer liquid crystal droplets. The spatial localization of motors is evocative of macromolecular localization in cellular assemblies such as the mitotic spindle. We develop a continuum model that captures the spatial localization based on liquid crystal theory. Finally, we investigate the dependence of motor size and liquid anisotropy on motor dynamics and localization. Our results inform physical mechanisms of self-organization and highlight the role of anisotropy in biological and bio-inspired soft materials.