Rab-mediated trafficking in the secondary cells of Drosophila male accessory glands and its role in fecundity

Abstract

It is known that the male seminal fluid contains factors that affect female post-mating behavior and physiology. In Drosophila, most of these factors are secreted by the two epithelial cell types that make up the male accessory gland: the main and secondary cells. Although secondary cells represent only 4% of the cells of the accessory gland, their contribution to the male seminal fluid is essential for sustaining the female post-mating response. To better understand the function of the secondary cells, here we investigate their molecular organization, particularly with respect to the intracellular membrane transport machinery. We determined that large vacuole-like structures found in the secondary cells are trafficking hubs labeled by Rab6, 7, 11 and 19. Furthermore, these cell-specific organelles are essential for the long-term post-mating behavior of females and that their formation is directly dependent upon Rab6. Our discovery adds to our understanding of Rab proteins function in secretory cells. We have created an online, open-access imaging resource as a valuable tool for the intracellular membrane and protein traffic community.