The mechanical response of vinculin.

Abstract

Vinculin is a mechanosensitive adaptor that links actin to cell-matrix and cell-cell adhesions. Known as a mechanoeffector, it is recruited to adhesion sites under force via mechanotransducers talin and α-catenin. Here, we examine vinculin's mechanical properties to assess its role as a mechanotransducer. We find that at physiological loading rates, vinculin domains unfold at forces of 5 to 15 pN and refold rapidly when forces drop to 1 pN. This behavior is reminiscent of force-dependent switches in talin and α-catenin, suggesting vinculin domains also function as molecular switches. Unfolding induces large extension changes up to 150 nm in steps of 20 to 30 nm. These findings reveal that vinculin exhibits a previously unrecognized mechanical response, with dynamic folding/unfolding under force acting as a buffering mechanism. Given its role as a scaffold for many proteins, this mechanosensitive behavior supports a model where vinculin functions directly as a mechanotransducer, recruiting binding partners in a force-dependent manner.