Phosphatidylinositol 4‐phosphate signaling in Drosophila

Phosphatidylinositol 4‐phosphate [PtdIns(4)P] has been shown to play key roles in intracellular trafficking and signaling in yeast and mammalian cells. However, much less is known about the requirement for this important phospholipid in multicellular organisms. To examine PtdIns(4)P in an animal model, we are studying PtdIns(4)P regulatory enzymes in the fruit fly Drosophila melanogaster . This allows us to take advantage of the evolutionarily conserved genes, powerful molecular genetic techniques and well‐characterized developmental biology available in the fly system. Using this system, we generated loss‐of‐function mutations in all three Drosophila PtdIns 4‐kinases (PI4Ks), as well as the PtdIns(4)P phosphatase Sac1. Our analysis of the mutant flies has revealed previously unsuspected functions for PtdIns(4)P regulatory enzymes in cytokinesis, gametogenesis and organelle biogenesis. Since these enzymes are highly conserved, we anticipate that our findings in Drosophila will uncover potential roles for these enzymes in human development and disease.