Regulated and Polarized PtdIns(3,4,5)P3 Accumulation Is Essential for Apical Membrane Morphogenesis in Photoreceptor Epithelial Cells

• DOI: 10.1016/j.cub.2005.11.068
• Publication Date: 2006-01-24T14:15:36Z
• Authors: Noelia Pinal; Deborah C.I. Gobe...; Lucy Collinson; Yasuyuki Fujita; Iain M. Cox; Clive Wilson; Franck Pichaud
• Keywords: 0303 health sciences; Agricultural and Biological Sciences(all); Microvilli; Biochemistry, Genetics and Molecular Biology(all); Cell Membrane; Intracellular Signaling Peptides and Proteins; PTEN Phosphohydrolase; Cell Polarity; Gene Expression Regulation, Developmental; Epithelial Cells; Adherens Junctions; Protein Serine-Threonine Kinases; Models, Biological; 03 medical and health sciences; Phosphatidylinositol Phosphates; SIGNALING; Morphogenesis; Animals; Drosophila Proteins; CELLBIO; Drosophila; Photoreceptor Cells, Invertebrate

In a specialized epithelial cell such as the Drosophila photoreceptor, a conserved set of proteins is essential for the establishment of polarity, its maintenance, or both--in Drosophila, these proteins include the apical factors Bazooka, D-atypical protein kinase C, and D-Par6 together with D-Ecadherin. However, little is known about the mechanisms by which such apical factors might regulate the differentiation of the apical membrane into functional domains such as an apical-most stack of microvilli or more lateral sub-apical membrane.We show that in photoreceptors Bazooka (D-Par3) recruits the tumor suppressor lipid phosphatase PTEN to developing cell-cell junctions (Zonula Adherens, za). za-localized PTEN controls the spatially restricted accumulation of optimum levels of the lipid PtdIns(3,4,5)P3 within the apical membrane domain. This in turn finely tunes activation of Akt1, a process essential for proper morphogenesis of the light-gathering organelle, consisting of a stack of F-actin rich microvilli within the apical membrane.Spatially localized PtdIns(3,4,5)P3 mediates directional sensing during neutrophil and Dictyostelium chemotaxis. We conclude that a conserved mechanism also operates during photoreceptor epithelial cell morphogenesis in order to achieve normal differentiation of the apical membrane.