Reconstitution of Actin Cytoskeletal Functions in Cell-sized Confinement

Abstract

The actin cytoskeleton drives various biological functions, including intracellular positioning of the nucleus and mitotic spindle, and cell motility. To gain physical insights into the regulatory mechanisms, we use water-in-oil droplets containing cytoplasmic extracts as a model system. We successfully reconstituted the symmetric/asymmetric positioning of a nucleus-sized object and actomyosin-based cell motility. A combination of physical modeling and molecular perturbation experiments identified the key physical parameters responsible for these processes, highlighting the roles of mechanical interactions among cytoskeletal proteins in organizing intracellular structures and biological functions.