title: PI4KIIIα is required for cortical integrity and cell polarity during Drosophila oogenesis.
abstract: Phosphoinositides regulate myriad cellular processes, acting as potent signaling molecules in conserved signaling pathways and as organelle gatekeepers that recruit effector proteins to membranes. Phosphoinositide-generating enzymes have been studied extensively in yeast and cultured cells, yet their roles in animal development are not well understood. Here, we analyze Drosophila melanogaster phosphatidylinositol 4-kinase IIIα (PI4KIIIα) during oogenesis. We demonstrate that PI4KIIIα is required for production of plasma membrane PtdIns4P and PtdIns(4,5)P2 and is crucial for actin organization, membrane trafficking and cell polarity. Female germ cells mutant for PI4KIIIα exhibit defects in cortical integrity associated with failure to recruit the cytoskeletal-membrane crosslinker Moesin and the exocyst subunit Sec5. These effects reflect a unique requirement for PI4KIIIα, as egg chambers from flies mutant for either of the other Drosophila PI4Ks, fwd or PI4KII, show Golgi but not plasma membrane phenotypes. Thus, PI4KIIIα is a vital regulator of a functionally distinct pool of PtdIns4P that is essential for PtdIns(4,5)P2-dependent processes in Drosophila development.
authors.affiliation: Program in Cell Biology, The Hospital for Sick Children, PGCRL, 686 Bay Street, Room 15.9716, Toronto, ON, M5G 0A4, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Tan
authors.forename: Karen
authors.initials: K
authors.lastname: Oh
authors.forename: Jason
authors.initials: J
authors.lastname: Burgess
authors.forename: David R
authors.initials: DR
authors.lastname: Hipfner
authors.forename: Julie A
authors.initials: JA
authors.lastname: Brill
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000201:enzymology*; D005089:Exocytosis; D005260:Female; D005804:Genes, Lethal; D005836:Genitalia, Female / Q000166:cytology; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D015778:Minor Histocompatibility Antigens; D009865:Oocytes / Q000502:physiology; D009866:Oogenesis; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000502:physiology*; D021381:Protein Transport
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D015778:Minor Histocompatibility Antigens; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; C502950:Sec5 protein, Drosophila; C099886:moesin, Drosophila; D017853:Phosphotransferases (Alcohol Group Acceptor); C402182:phosphatidylinositol phosphate 4-kinase
keywords: Exocyst; Moesin; PI 4-kinase; PI(4,5)P2; PI4P; Phosphatidylinositol 4-phosphate