De novo E-cadherin/catenin complex formation controls basal epithelial mechanics and force transmission for apoptotic cell clearance

Beyond serving as cohesive barriers, epithelial tissues are involved in tissue surveillance and actively clear apoptotic cells to regulate development, tissue homeostasis and inflammation across species. How epithelial cell shape is dynamically remodelled during phagocytosis while preserving tissue integrity has remained unclear. Using quantitative in vivo imaging of phagocyte-target interactions in zebrafish (Danio rerio) embryos, we show that basal and apical epithelial domains are mechanically decoupled, enabling engulfment without disrupting tissue cohesion. Notably, the cell-cell adhesion receptor E-cadherin dynamically assembles into functional E-cadherin/catenin complexes on the basal epithelial surface upon apoptotic cell interactions. Targeted perturbations and semi-synthetic in vivo assays reveal two specific mechano-regulatory functions of the E-cadherin/catenin complex in phagocytosis: -catenin acts as a physical linker and transmits forces from the actin cytoskeleton required for engulfment, independently of E-cadherin trans-binding. p120- catenin recruitment further restrains Myosin II activity at the phagocytic synapse, which is essential for successful clearance. We also show that E-cadherin has a conserved role in apoptotic cell clearance by the trophectoderm in the early mouse embryo. Our findings reveal that the E-cadherin/catenin complex can be dynamically repurposed on the basal epithelial surface, where it acts as a mechano-regulator of apoptotic cell clearance, beyond its canonical role in tissue cohesion.