Abstract
For a group of cells to migrate together, each cell must couple the polarity of its own migratory machinery with that of the other cells in the migrating group. Although collective cell migrations are common in animal development, it is not understood how protrusions are coherently polarized within groups of migrating epithelial cells. We address this problem in the collective migration of the Drosophila melanogaster follicular epithelial cells, demonstrating that the atypical cadherin Fat2 relays polarity information between neighboring cells, causing them to align their lamellipodia and migrate together. Fat2 localizes the WAVE complex to the leading edge of each cell, where the WAVE complex builds polarized lamellipodia. In Fat2’s absence, the WAVE complex becomes enriched at fluctuating positions around the cell perimeter, resulting in short-lived and spatially disordered protrusive regions, ultimately causing collective migration to fail. In wild-type tissue, Fat2 puncta along the trailing edge of each cell concentrate the WAVE complex in corresponding puncta just across the cell-cell interface, restricting WAVE complex activity and protrusions to one stable leading edge. In summary, migrating cells couple their protrusive activity to that of their neighbors using a polarized transmembrane cue. We propose that this mechanism enables the tissue to achieve persistent, days-long directed migration.
Competing Interest Statement
The authors have declared no competing interest.
