Adherent cells sustain membrane tension gradients independently of migration.

Tension propagates in lipid bilayers over hundreds of microns within milliseconds, seemingly precluding the formation of tension gradients. Nevertheless, plasma membrane tension gradients have been reported in migrating cells and along growing axons. Here, we show that the mechanosensitive, fluorescent membrane probe Flipper-TR visualizes membrane tension gradients in artificial and cellular membranes. Images of tension gradients allow their quantitative characterization, showing that they are long-ranged and linear in all migratory adherent cells. Using this tool, we unexpectedly reveal that tension gradients also exist in non-migrating adherent cells while they are absent in non-adherent migrating cells. This suggests that actomyosin forces can generate tension gradients even in non-moving cells, but that adhesion to a substrate is needed to sustain these gradients. Treatment of cells with drugs perturbing actomyosin show that branched actin increases tension, creating gradients. Furthermore, specific adhesion mediated by clathrin plaques colocalizes with regions of low tension, and chemical disruption of clathrin plaques strongly affect tension gradients. Altogether, our results show that the combined action of actomyosin and adhesion forces create tension gradients in the plasma membrane of adherent cells, even the ones not migrating.