Amine Mehidi

Abstract Tension propagates extremely fast in lipid bilayers, precluding the formation of tension gradients. Nevertheless, plasma membrane tension gradients have been evidenced in migrating cells and along axons. Here, using a fluorescent membrane tension probe, we show that membrane tension gradients exist in all adherent cells, whether they migrate or not. Non-adhering cells do not display tension gradients.

Highlights • Rac1 immobilization at the lamellipodium tip correlates with its activation • Rac1 immobilization depends on effector binding, including WRC • RhoA does not display selective immobilization at the lamellipodium tip • Local Rac1 activation at the lamellipodium tip triggers membrane protrusion Summary The spatiotemporal coordination of actin regulators in the lamellipodium determines the dynamics and architecture of branched F-actin networks during cell migration.