title: Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis.
abstract: Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the importance of cell polarity, its underlying mechanisms are still largely unknown, including the definition and distinctiveness of the polar domains within the PM. Here, we show in Arabidopsis thaliana that the signaling membrane components, the phosphoinositides phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] as well as PtdIns4P 5-kinases mediating their interconversion, are specifically enriched at apical and basal polar plasma membrane domains. The PtdIns4P 5-kinases PIP5K1 and PIP5K2 are redundantly required for polar localization of specifically apical and basal cargoes, such as PIN-FORMED transporters for the plant hormone auxin. As a consequence of the polarity defects, instructive auxin gradients as well as embryonic and postembryonic patterning are severely compromised. Furthermore, auxin itself regulates PIP5K transcription and PtdIns4P and PtdIns(4,5)P2levels, in particular their association with polar PM domains. Our results provide insight into the polar domain-delineating mechanisms in plant cells that depend on apical and basal distribution of membrane lipids and are essential for embryonic and postembryonic patterning.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Tejos
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Michael
authors.initials: M
authors.lastname: Sauer
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.affiliation: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
authors.forename: Miriam
authors.initials: M
authors.lastname: Palacios-Gomez
authors.affiliation: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
authors.forename: Hongjiang
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Heilmann
authors.affiliation: Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Ringo
authors.initials: R
authors.lastname: van Wijk
authors.affiliation: Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Joop E M
authors.initials: JE
authors.lastname: Vermeer
authors.affiliation: Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Heilmann
authors.affiliation: Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Teun
authors.initials: T
authors.lastname: Munnik
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria jiri.friml@ist.ac.at.
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml