The integrin-talin complex under force.

Integrins are the major transmembrane cellular adhesion receptors. Talin binds to integrins with its head domain and links them to the actin cytoskeleton with its rod domain, acting as the force linkage between the extracellular matrix and the cytoskeleton. It is unknown how forces in different directions affect the integrin-talin complex. We show that small forces applied to the integrin-talin complex breaks a salt bridge between the integrins α- and β-subunit, unlocking the integrin from its resting state. Forces parallel to the membrane lead to a zipper-like unbinding. Forces normal to the membrane induce strengthening of the complex. Our results indicate that the integrin-talin complex is physiologically optimized to be strengthened by applied forces at certain locations within the cell.