Structure and function of the GTP binding protein Gtr1 and its role in phosphate transport in Saccharomyces cerevisiae

Research output: Contribution to journalArticle


The Pho84 high-affinity phosphate permease is the primary phosphate transporter in the yeast Saccharomyces cerevisiae under phosphate-limiting conditions. The soluble G protein, Gtr1, has previously been suggested to be involved in the derepressible Pho84 phosphate uptake function. This idea was based on a displayed deletion phenotype of Deltagtr1 similar to the Deltapho84 phenotype. As of yet, the mode of interaction has not been described. The consequences of a deletion of gtr1 on in vivo Pho84 expression, trafficking and activity, and extracellular phosphatase activity were analyzed in strains synthesizing either Pho84-green fluorescent protein or Pho84-myc chimeras. The studies revealed a delayed response in Pho84-mediated phosphate uptake and extracellular phosphatase activity under phosphate-limiting conditions. EPR spectroscopic studies verified that the N-terminal G binding domain (residues 1-185) harbors the nucleotide responsive elements. In contrast, the spectra obtained for the C-terminal part (residues 186-310) displayed no evidence of conformational changes upon GTP addition.


External organisations
  • Stockholm University
  • University of Kalmar
  • University of California System
Research areas and keywords


  • Electron Spin Resonance Spectroscopy, Gene Deletion, Green Fluorescent Proteins, Models, Molecular, Monomeric GTP-Binding Proteins, Phosphates, Protein Binding, Protein Conformation, Protein Transport, Proton-Phosphate Symporters, Recombinant Fusion Proteins, Saccharomyces cerevisiae Proteins, Structure-Activity Relationship, Thermodynamics, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)511-7
Issue number2
Publication statusPublished - 2005 Jan 18
Publication categoryResearch
Externally publishedYes