The function of α-Catenin mechanosensing in tissue morphogenesis

α-catenin couples the cadherin-catenin complex to the actin cytoskeleton. The mechanosensitive α-catenin M region undergoes conformational changes upon application of force to recruit binding partners. Here, we took advantage to the tension landscape in the Drosophila embryo to define three different states of α-catenin mechanosensing in support of cell adhesion. Low, medium, and high tension contacts showed α-catenin M region-dependent low, medium, and high levels of Vinculin and Ajuba recruitment. In contrast, Afadin/Canoe acts in parallel to α-catenin at bicellular low and medium tension junctions, but requires an interaction with α-catenin for its tension-sensitive enrichment at high-tension tricellular junctions. Individual M region domains make complex contributions to cell adhesion through their impact on binding partner recruitment, and redundancies with the function of Afadin/Canoe. Our data argue that α-catenin and its interaction partners are part of a cooperative and partially redundant, mechanoresponsive network that supports AJs remodelling during morphogenesis.