View Program - 63rd Annual Drosophila Research Conference

Adult stem cells are crucial for regeneration, tissue repair after injury, and developmental processes such as spermatogenesis. Stem cells exist in a dynamic microenvironment termed the niche that provides signals to ensure the maintenance and self-renewal of the adult stem cell population. An appreciation of the dynamic communication between stem cells and their niche is vital to understand processes such as reproduction, oncogenesis, aging, development, and regeneration. Here I use the testis of Drosophila melanogaster as a model to investigate the role of endocytosis, and the ESCRT complexes specifically, in signaling within the stem cell niche. Endocytosis regulates a myriad of signaling pathways as well as cellular communication. The ESCRT complexes are involved in a variety of cellular processes, such as multivesicular body formation and particle budding, and are considered endocytic tumor suppressor genes due to their role in signal attenuation. Knockdown of ESCRTs in somatic stem cells causes niche cells to become significantly enlarged and exhibit abnormal morphology. Furthermore, Unpaired, a ligand for the JAK-STAT pathway normally secreted by niche cells, accumulates within the cytoplasm of niche cells upon ESCRT knockdown in somatic stem cells. As knockdown of ESCRTs in somatic stem cells affects the morphology of niche cells, this suggests that ESCRTs mediate signaling from somatic stem cells back to their niche to prevent niche hypertrophy. I am further exploring the role of additional pathways in modulating this signaling. A deeper understanding of the signaling dynamics within the Drosophila testis stem cell niche will have further implications for stem cell niches in other tissues and organisms as well as processes such as regeneration and renewal.

The role of ESCRTs in signaling within the testis stem cell niche