View Program - 63rd Annual Drosophila Research Conference

Collective migration of numerous cell types including neural crest, endothelial, epithelial, tumor and stromal cells contributes to normal development, wound healing, angiogenesis, and tumor metastasis. The study of multiple in vitro and in vivo models has revealed mechanisms promoting collective polarization, motility, direction-sensing, and adhesion. Border cells in the Drosophila ovary serve as a useful in vivo model for collective cell migration. Border cells are a group of four to six migratory cells that surround and carry two non-migratory polar cells in between nurse cells in developing egg chambers. Here we report that cryptic basal protrusions in border cells ensure cluster cohesion. We further show that the basolateral complex protein scribble promotes cryptic protrusions by localizing LGL and the Rac guanine nucleotide exchange factor Cdep to membranes. The finding that membrane targeting of Cdep is sufficient to suppress scribble knockdown suggests that Cdep is a major effector for the basolateral complex. Additionally, Scribble restricts cryptic protrusions from encroaching onto the apical domain, which is essential for proper docking of the cluster apical surface to the oocyte at the end of migration. This work suggests novel roles for cryptic protrusions, Scribble, and Cdep in the collective and cooperative movement of a heterotypic cell group in vivo.

Coordination of border cell cohesion through localization of the RacGEF Cdep by the scribble complex.