Adipocyte-Derived Amino Acid Storage Proteins Are Required for Germline Stem Cell Maintenance in Adult Drosophila Females

This study investigates the role of adipocyte-derived amino acid storage proteins in maintaining germline stem cells (GSCs) in adult female <i>Drosophila</i>. The researchers found that knocking down specific storage proteins, <i>Larval serum protein 1</i> (<i>Lsp1</i>) α/β/γ and <i>Larval serum protein 2</i> (<i>Lsp2</i>), in adipocytes leads to a decrease in GSC maintenance. This decrease is linked to reduced Target of Rapamycin (TOR) signaling in GSCs, indicating impaired amino acid sensing. Additionally, proteins involved in storage protein reabsorption, Fat body protein 1 (Fbp1) and Fat body protein 2 (Fbp2), are present in ovarian follicle cells but are not required for GSC maintenance, suggesting other roles for these proteins in oogenesis. The findings reveal a novel function for amino acid storage proteins in adult <i>Drosophila</i> and their influence on tissue stem cell lineages.