Twofold mechanosensitivity ensures actin cortex reinforcement upon peaks in mechanical tension

Research output: Preprint/documentation/report › Preprint


The actin cortex is an active biopolymer network underneath the plasma membrane at the periphery of mammalian cells. It is a major regulator of cell shape through the generation of active cortical tension. In addition, the cortex constitutes a mechanical shield that protects the cell during mechanical agitation. Cortical mechanics is tightly controlled by the presence of actin cross-linking proteins, that dynamically bind and unbind actin filaments. Cross-linker actin bonds are weak non-covalent bonds whose bond lifetime is likely affected by mechanical tension in the actin cortex making cortical composition inherently mechanosensitive. Here, we present a quantitative study of changes in cortex composition and turnover dynamics upon short-lived peaks in active and passive mechanical tension in mitotic HeLa cells. Our findings disclose a twofold mechanical reinforcement strategy of the cortex upon tension peaks entailing i) a direct catch-bond mechanosensitivity of cross-linkers filamin and $\alpha$-actinin and ii) an indirect cortical mechanosensitivity that triggers actin cortex reinforcement via enhanced polymerization of actin. We thereby disclose a `molecular safety belt' mechanism that protects the cortex from injury upon mechanical challenges.


Original languageEnglish
Number of pages24
Publication statusPublished - 12 May 2023
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External IDs

ORCID /0000-0002-6209-2364/work/142658680
ORCID /0000-0002-2213-2763/work/142659214
ORCID /0000-0002-2433-916X/work/142660168