Distinct SNARE Proteins Regulate Intracellular Trafficking, Secretion, and Polarized Deposition of the Basement Membrane in the Drosophila Follicular Epithelium

Basement membrane (BM) is an essential part of epithelial cell architecture. BM is a specialized extracellular matrix. BM assembles on the basal side outside of plasma membrane. It carries out important biological functions such as maintaining tissue shape, enabling cellular migration, and facilitating communication between cells. Defects in BM assembly or composition can cause a range of diseases. However, the regulatory mechanisms governing polarized deposition of BM are not well understood. To study this process, I use the follicular epithelium of the Drosophila melanogaster ovary as a model system. In this study, I analyzed the role of SNARE proteins in intracellular trafficking, secretion and polarized deposition of the BM. SNAREs are crucial for membrane fusion. I performed a genetic screen targeting all SNARE proteins in Drosophila. Individual knockdowns of multiple SNARE family members resulted in BM mislocalization. Three distinct mislocalization phenotypes were observed: Intracellular accumulation of BM, apical deposition of BM, or a combination of apical deposition and intracellular accumulation of BM. Taken together, these observations suggest that multiple SNARE family members contribute to the intracellular trafficking, secretion, and polarized deposition of BM proteins.