Présentation
The collective migration of cells within an epithelial sheet underlies tissue remodeling events associated with morphogenesis, wound repair, and the metastatic cascade. Yet little is known about how each epithelial cell coordinates its movements with those of its neighbors. Studying the rotational migration of the follicular epithelium in Drosophila, we have identified two signaling pathways that these cells use to coordinate their movements for collective motility. In the first half of the seminar, I will show that the cadherin Fat2 and the receptor tyrosine phosphatase Lar send short-range signals within the tissue plane to coordinate leading edge and trailing edge dynamics between neighboring cells. In the second half of the seminar, I will show that Semaphorin-5c and Plexin A also provide important signals required for collective migration, and that these signals appear to antagonize Fat2-Lar signaling via an unknown mechanism. Interestingly, Fat2, Lar, Semaphorin-5c and Plexin A all play key roles in wiring the nervous system. Thus, the same cues that guide neurites through the body may also be used by epithelial cells to influence the migratory behavior of their neighbors.