Shape change in cytoskeleton surface by active self-organization of nematic structures.

Morphogenetic events in the actin cytoskeleton surface result from an interplay between nematic structures, hydrodynamic flow, density accumulation, geometry, topology, and shape deformation. In this work, we propose a theoretical model to explore the physical mechanisms, regulated by the aforementioned interplay, that leads to self-organized shape changes in a cytoskeleton surface. This model is based on Onsager's formalism, according to which the dynamics result from a variational principle where free-energy release, dissipation, and activity compete. We perform a linear stability analysis of the model to predict an unstable regime that results in the various deformation modes in a cytoskeleton surface. Lastly, we used a finite element-based computational framework to explore the model in a fully non-linear regime and investigate the role of the deformation modes in morphogenetic events such as cellular oscillation, division, motility and wound healing.