Inositol pyrophosphates promote the interaction of SPX domains with the coiled-coil motif of PHR transcription factors to regulate plant phosphate homeostasis
Creators: name: Ried, Martina K.
name: Wild, Rebekka
name: Zhu, Jinsheng
name: Pipercevic, Joka
name: Sturm, Kristina
name: Broger, Larissa
name: Harmel, Robert K.
name: Abriata, Luciano A.
name: Hothorn, Ludwig A.
name: Fiedler, Dorothea
name: Hiller, Sebastian
name: Hothorn, Michael
Publisher: name: London : Nature Publishing Group
Year: 2021
Subjects: subject: binding protein
subject: brassinosteroid
subject: brassinosteroid receptor kinase bri1
subject: inhibitor protein
subject: inhibitor protein bki1
subject: inositol phosphate
subject: inositol pyrophosphate
subject: Pi starvation response transcription factor
subject: plant protein
subject: receptor
subject: spx domain containing protein
subject: transcription factor
subject: unclassified drug
subject: Arabidopsis protein
subject: nuclear protein
subject: PHR1 protein, Arabidopsis
subject: protein binding
subject: pyrophosphoric acid derivative
subject: recombinant protein
subject: SPX1 protein, Arabidopsis
subject: concentration (composition)
subject: DNA
subject: eukaryote
subject: homeostasis
subject: inorganic phosphorus
subject: mutation
subject: phosphate
subject: protein
subject: starvation
subject: Agrobacterium tumefaciens
subject: Arabidopsis thaliana
subject: Chaetomium thermophilum
subject: comparative study
subject: complex formation
subject: controlled study
subject: crystal structure
subject: dimerization
subject: dissociation constant
subject: DNA binding
subject: gene expression
subject: gene interaction
subject: gene mutation
subject: gene rearrangement
subject: in vitro study
subject: isothermal titration calorimetry
subject: metabolic regulation
subject: molecular cloning
subject: nonhuman
subject: nuclear magnetic resonance spectroscopy
subject: oligomerization
subject: phosphate metabolism
subject: point mutation
subject: promoter region
subject: protein domain
subject: protein expression
subject: protein motif
subject: protein protein interaction
subject: protein structure
subject: quantitative analysis
subject: seedling
subject: site directed mutagenesis
subject: stoichiometry
subject: tetramerization
subject: Arabidopsis
subject: gene expression regulation
subject: genetics
subject: isolation and purification
subject: metabolism
subject: physiology
subject: signal transduction
subject: ultrastructure
subject: X ray crystallography
subject: Eukaryota
subject: Amino Acid Motifs
subject: Arabidopsis Proteins
subject: Crystallography, X-Ray
subject: Diphosphates
subject: Gene Expression Regulation, Plant
subject: Inositol Phosphates
subject: Mutation
subject: Nuclear Proteins
subject: Protein Binding
subject: Protein Domains
subject: Recombinant Proteins
subject: Signal Transduction
subject: Transcription Factors
subject: Dewey Decimal Classification::500 | Naturwissenschaften

description: Phosphorus is an essential nutrient taken up by organisms in the form of inorganic phosphate (Pi). Eukaryotes have evolved sophisticated Pi sensing and signaling cascades, enabling them to stably maintain cellular Pi concentrations. Pi homeostasis is regulated by inositol pyrophosphate signaling molecules (PP-InsPs), which are sensed by SPX domain-containing proteins. In plants, PP-InsP-bound SPX receptors inactivate Myb coiled-coil (MYB-CC) Pi starvation response transcription factors (PHRs) by an unknown mechanism. Here we report that a InsP8–SPX complex targets the plant-unique CC domain of PHRs. Crystal structures of the CC domain reveal an unusual four-stranded anti-parallel arrangement. Interface mutations in the CC domain yield monomeric PHR1, which is no longer able to bind DNA with high affinity. Mutation of conserved basic residues located at the surface of the CC domain disrupt interaction with the SPX receptor in vitro and in planta, resulting in constitutive Pi starvation responses. Together, our findings suggest that InsP8 regulates plant Pi homeostasis by controlling the oligomeric state and hence the promoter binding capability of PHRs via their SPX receptors.