Head/tail interaction of vinculin influences cell mechanical behavior

This study evaluates the influence of vinculin in closed conformation on the mechanical properties of cells. We demonstrate that MEFvin−/− cells transfected with the eGFP-vinculin mutant A50I (talin-binding-deficient-vinculin in a constitutively closed conformation) show 2-fold lower stiffness and focal adhesion density compared to MEFvin+/+ and MEFRescue cells. MEFA50I cells are as stiff as MEFvin−/− cells with similar focal adhesion density. Further, 2D traction microscopy indicates that MEFA50I and MEFvin−/− cells generate 3- to 4-fold less strain energy than MEFvin+/+ and MEFRescue cells. These results demonstrate that vinculin’s mechano-coupling function is dependent on its conformational state.

Research highlights
► The open conformation of the vinculin molecule facilitates the binding of other focal adhesion proteins.
► In this configuration, vinculin is incorporated in the focal adhesion complex, and the number of focal adhesions increase.
► The higher focal adhesion density and the binding to the actin cytoskeleton allows for stronger cellular tractions.