Structure of the SPX domain of the human phosphate transporter XPR1 in complex with a sulfate ion

Experimental Data Snapshot

  • Resolution: 2.43 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 

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Control of eukaryotic phosphate homeostasis by inositol polyphosphate sensor domains.

Wild, R.Gerasimaite, R.Jung, J.Y.Truffault, V.Pavlovic, I.Schmidt, A.Saiardi, A.Jessen, H.J.Poirier, Y.Hothorn, M.Mayer, A.

(2016) Science 352: 986-990

  • DOI: https://doi.org/10.1126/science.aad9858
  • Primary Citation of Related Structures:  
    5IIG, 5IIQ, 5IIT, 5IJH, 5IJJ, 5IJP

  • PubMed 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.

  • Organizational Affiliation

    Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Xenotropic and polytropic retrovirus receptor 1
A, B
213Homo sapiensMutation(s): 0 
Gene Names: XPR1SYG1XR
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UBH6 (Homo sapiens)
Explore Q9UBH6 
Go to UniProtKB:  Q9UBH6
GTEx:  ENSG00000143324 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UBH6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.43 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.95α = 90
b = 80.32β = 90
c = 97.86γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
European Research CouncilSwitzerland310856

Revision History  (Full details and data files)

  • Version 1.0: 2016-04-27
    Type: Initial release
  • Version 1.1: 2016-06-01
    Changes: Database references
  • Version 1.2: 2024-01-10
    Changes: Data collection, Database references, Refinement description