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Gene Review

GTR1  -  Rag GTPase GTR1

Saccharomyces cerevisiae S288c

Synonyms: GTP-binding protein GTR1, YM7056.05, YML121W
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Disease relevance of GTR1


High impact information on GTR1

  • The complex contains two small GTPases (Gtr1p and Gtr2p) and three other proteins (Ybr077c, Ykr007w and Ltv1p) that are located in the late endosomal membrane [2].
  • The latter phenotypes were shown to be due to a defect in Pi uptake, and the Gtr1 protein was found to be functionally associated with the Pho84 Pi transporter [3].
  • In Saccharomyces cerevisiae, this gene is distal to the TUB3 locus on the left arm of chromosome XIII and is named GTR1 [3].
  • Disruption of the GTR1 gene resulted in slow growth at 30 degrees C and no growth at 15 degrees C; other phenotypes resembled those of pho84 mutants and included constitutive synthesis of repressible acid phosphatase, reduced Pi transport activity, and resistance to arsenate [3].
  • GTR1 encodes a protein consisting of 310 amino acid residues containing, in its N-terminal region, the characteristic tripartite consensus elements for binding GTP conserved in GTP-binding proteins, except for histidine in place of a widely conserved aspargine residue in element III [3].

Biological context of GTR1

  • We found that gtr1-11 caused a single amino acid substitution in Gtr1p, forming S20L, which is a putative GDP-bound mutant protein, while Gtr1p has been reported to bind to GTP alone [4].
  • A multiple sequence alignment indicated that RagA and RagB cannot be assigned to any of the known subfamilies of Ras-related GTPases but exhibit a 52% identity with a yeast protein (Gtr1) presumably involved in phosphate transport and/or cell growth [5].

Physical interactions of GTR1


Other interactions of GTR1

  • S. cerevisiae possesses a novel gene, GTR2, which is homologous to GTR1 [4].
  • The other three genes, GTR1, PHO86 and PHO87, are also suggested to be involved in the P(i) uptake system [6].
  • Furthermore, gtr1-11 suppressed the rna1-1, temperature-sensitive mutant of the Gsp1p GTPase-activating protein, but not the srp1-31, temperature-sensitive mutant of the S. cerevisiae importin alpha homologue. mtr1-2, srm1-1 and prp20-1 were also suppressed by overexpression of the mutated Gtr1p, Gtr1-11p [7].
  • The association of Gtr1p with Rpc19p occurred in a GTP-form-specific manner [8].
  • This genetic system has also led us to identify Gtr1 as an Meh1 interacting protein [9].


  1. Saccharomyces cerevisiae GTPase complex: Gtr1p-Gtr2p regulates cell-proliferation through Saccharomyces cerevisiae Ran-binding protein, Yrb2p. Wang, Y., Nakashima, N., Sekiguchi, T., Nishimoto, T. Biochem. Biophys. Res. Commun. (2005) [Pubmed]
  2. A conserved GTPase-containing complex is required for intracellular sorting of the general amino-acid permease in yeast. Gao, M., Kaiser, C.A. Nat. Cell Biol. (2006) [Pubmed]
  3. Putative GTP-binding protein, Gtr1, associated with the function of the Pho84 inorganic phosphate transporter in Saccharomyces cerevisiae. Bun-Ya, M., Harashima, S., Oshima, Y. Mol. Cell. Biol. (1992) [Pubmed]
  4. Saccharomyces cerevisiae putative G protein, Gtr1p, which forms complexes with itself and a novel protein designated as Gtr2p, negatively regulates the Ran/Gsp1p G protein cycle through Gtr2p. Nakashima, N., Noguchi, E., Nishimoto, T. Genetics (1999) [Pubmed]
  5. Cloning of a novel family of mammalian GTP-binding proteins (RagA, RagBs, RagB1) with remote similarity to the Ras-related GTPases. Schürmann, A., Brauers, A., Massmann, S., Becker, W., Joost, H.G. J. Biol. Chem. (1995) [Pubmed]
  6. A putative new membrane protein, Pho86p, in the inorganic phosphate uptake system of Saccharomyces cerevisiae. Yompakdee, C., Bun-ya, M., Shikata, K., Ogawa, N., Harashima, S., Oshima, Y. Gene (1996) [Pubmed]
  7. Putative GTPase Gtr1p genetically interacts with the RanGTPase cycle in Saccharomyces cerevisiae. Nakashima, N., Hayashi, N., Noguchi, E., Nishimoto, T. J. Cell. Sci. (1996) [Pubmed]
  8. Association of the GTP-binding protein Gtr1p with Rpc19p, a shared subunit of RNA polymerase I and III in yeast Saccharomyces cerevisiae. Todaka, Y., Wang, Y., Tashiro, K., Nakashima, N., Nishimoto, T., Sekiguchi, T. Genetics (2005) [Pubmed]
  9. ERS1 encodes a functional homologue of the human lysosomal cystine transporter. Gao, X.D., Wang, J., Keppler-Ross, S., Dean, N. FEBS J. (2005) [Pubmed]
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