Project B10

Spatiotemporal Regulation of Secretory Lysosome Trafficking Controls Epithelial Tube Fusion

Organs like the vascular system and the kidney originate from separate primordia that fuse to form interconnected tubular networks. Despite their fundamental role in organogenesis, the cellular and molecular mechanisms underlying tube fusion events are not clear. Tracheal tube fusion in Drosophila shares similarities with anastomosis formation during angiogenesis in vertebrates, suggesting that underlying cellular and molecular mechanisms may be conserved. We use the fly tracheal system as a model to understand how the membrane trafficking machinery mediates lumen formation and fusion of luminal membranes in epithelial tubes. Through genetic screens we identified new components required for lumen fusion. In this CRC we will investigate the role of secretory lysosomes, dynamic vesicles of late endosomal and lysosomal origin, as well as their calcium-dependent regulation during tracheal tube fusion. We will determine how secretory lysosomes deliver membrane material to specific cellular interfaces to connect invading lumina in tracheal fusion cells.