A dynamic contractile F-actin network reconstituted in <i>Xenopus </i>egg extract

The actin cytoskeleton in most animal cells is a highly dynamic multi-component network that rapidly turns over, adapts, generates forces and moves. The continuous remodelling of the cytoskeleton and spontaneous flows have been extensively visualized in a variety of cellular processes, including intracellular transport, cell migration and division. It remains unclear how the spatiotemporal interactions of the various components self-organize to give rise to global F-actin flows. We reconstituted a fully active model cytoskeleton in water-in-oil emulsion droplets containing xenopus egg extract. We observed steady state directed flows and non-equilibrium phase separation. We analysed the flow and examined the contractile stress generated by actin-myosin interactions.