Cooperative regulation of adherens junction elongation through Epidermal Growth Factor Receptor (EGFR) activation.

The mechanisms controlling the elongation rates of adherens junctions are poorly characterized and lag behind our understanding of those controlling their static properties. In suspended cell aggregates, we found that the speed of de novo junction formation between two cells increases with the number of junctions that the cells are already engaged in. This cooperative effect is driven by the transient activation of the Epidermal Growth Factor Receptor (EGFR) upon junction formation. EGFR activation then regulates the actin cytoskeleton turnover while cortical tension remains unaltered. Overall, we show that EGFR activation regulates the elongation speed of junctions (kinetype) without affecting their final size (phenotype) in such aggregates.