"PI4P Drives Cell Morphogenesis in Drosophila"

Phosphatidylinositol (PI) phosphates (PIPs) are membrane lipids with key roles in cell growth, signaling and morphogenesis. Altered levels of PIPs are associated with human diseases such as cancer, yet little is known about the normal roles of PIPs during animal development. Using Drosophila as a model system, we have uncovered novel roles for one of the PIPs [PI 4-phosphate (PI4P)] and its regulatory enzymes in critical aspects of cell morphogenesis during development. We showed that the PI 4-kinase Fwd (which synthesizes PI4P) is needed for spermatocyte cytokinesis (Polevoy et al., 2009); that PI4KIIIalpha synthesizes plasma membrane PIPs during oogenesis (Tan et al., in press); that PI4KII promotes trafficking during glue granule biogenesis in the larval salivary gland (Burgess et al., 2012); and that PI4KII and the PI 4-phosphatase Sac1 regulate pigmentation in the Drosophila eye (Del Bel et al., in preparation). Our current studies are focused on determining how PIP pathway enzymes are regulated and identifying their targets in these developmental processes. As PIPs and their regulatory enzymes are found in all eukaryotes, our research will identify conserved cellular mechanisms fundamental to human development and disease.