Local Contractions Test Rigidity of E-Cadherin Adhesions

E-cadherin is a major cell-cell adhesion molecule involved in mechanotransduction at cell-cell contacts in tissues. Since epithelial cells respond to rigidity and tension in the tissue through E-cadherin, there must be active processes that test and respond to the mechanical properties of these adhesive contacts. Using sub-micrometer, E-cadherin-coated PDMS pillars, we find that cells generate active contractions between E-cadherin adhesions and pull to a constant distance for a constant duration, irrespective of varying pillar rigidity. These cadherin contractions require non-muscle myosin IIB, tropomyosin 2.1, α-catenin and binding of vinculin to α-catenin; plus, they are correlated with mechanosensitive cell spreading. Without contractions, cells fail to spread to different areas on soft and rigid surfaces and to maintain monolayer integrity. Thus, we suggest that epithelial cells test the rigidity of neighboring cells by cadherin contractions.