title: Control of eukaryotic phosphate homeostasis by inositol polyphosphate sensor domains.
abstract: Phosphorus is a macronutrient taken up by cells as inorganic phosphate (P(i)). How cells sense cellular P(i) levels is poorly characterized. Here, we report that SPX domains--which are found in eukaryotic phosphate transporters, signaling proteins, and inorganic polyphosphate polymerases--provide a basic binding surface for inositol polyphosphate signaling molecules (InsPs), the concentrations of which change in response to P(i) availability. Substitutions of critical binding surface residues impair InsP binding in vitro, inorganic polyphosphate synthesis in yeast, and P(i) transport in Arabidopsis In plants, InsPs trigger the association of SPX proteins with transcription factors to regulate P(i) starvation responses. We propose that InsPs communicate cytosolic P(i) levels to SPX domains and enable them to interact with a multitude of proteins to regulate P(i) uptake, transport, and storage in fungi, plants, and animals.
authors.affiliation: Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Wild
authors.affiliation: Department of Biochemistry, University of Lausanne, Lausanne, Switzerland.
authors.forename: Ruta
authors.initials: R
authors.lastname: Gerasimaite
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.
authors.forename: Ji-Yul
authors.initials: JY
authors.lastname: Jung
authors.affiliation: Department of Biochemistry, Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Vincent
authors.initials: V
authors.lastname: Truffault
authors.affiliation: Department of Chemistry and Pharmacy, University of Zürich, Zürich, Switzerland.
authors.forename: Igor
authors.initials: I
authors.lastname: Pavlovic
authors.affiliation: Department of Biochemistry, University of Lausanne, Lausanne, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Schmidt
authors.affiliation: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Saiardi
authors.affiliation: Department of Chemistry and Pharmacy, University of Zürich, Zürich, Switzerland. Institute of Organic Chemistry, Albert-Ludwigs-University Freiburg, Freiburg, Germany.
authors.forename: Henning Jacob
authors.initials: HJ
authors.lastname: Jessen
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland. yves.poirier@unil.ch michael.hothorn@unige.ch andreas.mayer@unil.ch.
authors.forename: Yves
authors.initials: Y
authors.lastname: Poirier
authors.affiliation: Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. yves.poirier@unil.ch michael.hothorn@unige.ch andreas.mayer@unil.ch.
authors.forename: Michael
authors.initials: M
authors.lastname: Hothorn
authors.affiliation: Department of Biochemistry, University of Lausanne, Lausanne, Switzerland. yves.poirier@unil.ch michael.hothorn@unige.ch andreas.mayer@unil.ch.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mayer
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics; D018360:Crystallography, X-Ray; D003600:Cytosol / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007294:Inositol / Q000378:metabolism*; D028061:Phosphate Transport Proteins / Q000737:chemistry* / Q000235:genetics; D010758:Phosphorus / Q000378:metabolism*; D011122:Polyphosphates / Q000378:metabolism*; D017433:Protein Structure, Secondary / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry; D017855:Transferases (Other Substituted Phosphate Groups) / Q000737:chemistry* / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C460111:PHO1 protein, Arabidopsis; D028061:Phosphate Transport Proteins; D011122:Polyphosphates; D014157:Transcription Factors; D010758:Phosphorus; D007294:Inositol; D017855:Transferases (Other Substituted Phosphate Groups)