Mesoscale Dynamics of Spectrin and Acto-Myosin shape Membrane Territories during Mechanoresponse

Abstract

The spectrin cytoskeleton is a major component of the cell cortex. While ubiquitously expressed, its dynamic interaction with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, is poorly understood. Here, we investigated how the spectrin cytoskeleton re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We found spectrin and acto-myosin cytoskeletons to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence to organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin cytoskeletons necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.