ApiLoc - A database of published protein sub-cellular localisation in Apicomplexa

version 3 (curated until May 28, 2011)

Host-derived glucose and its transporter in the obligate intracellular pathogen Toxoplasma gondii are dispensable by glutaminolysis.

Blume, M., Rodriguez-Contreras, D., Landfear, S., Fleige, T., Soldati-Favre, D., Lucius, R., Gupta, N. (2009 Aug 4, Proc Natl Acad Sci U S A)

Toxoplasma gondii, as an obligate intracellular and promiscuous pathogen of mammalian cells, utilizes host sugars for energy and to generate glycoconjugates that are important to its survival and virulence. Here, we report that T. gondii glucose transporter (TgGT1) is proficient in transporting mannose, galactose, and fructose besides glucose, and serves as a major hexose transporter at its plasma membrane. Toxoplasma harbors 3 additional putative sugar transporters (TgST1-3), of which TgST2 is expressed at its surface, whereas TgST1 and TgST3 are intracellular. Surprisingly, TgGT1 and TgST2 are nonessential to the parasite as their ablations inflict only a 30% or no defect in its intracellular growth, respectively. Indeed, Toxoplasma can also tolerate the deletion of both genes while incurring no further growth phenotype. Unlike Deltatgst2, the modest impairment in Deltatggt1 and Deltatggt1/Deltatgst2 mutants is because of a minor delay in their intracellular replication, which is a direct consequence of the abolished import of glucose. The Deltatggt1 displays an attenuated motility in defined minimal media that is rescued by glutamine. TgGT1-complemented parasites show an entirely restored growth, motility, and sugar import. The lack of exogenous glucose in Deltatggt1 culture fails to accentuate its intrinsic growth defect and prompts it to procure glutamine to sustain its metabolism. Unexpectedly, in vivo virulence of Deltatggt1 in mice remains unaffected. Taken together, our data demonstrate that glucose is nonessential for T. gondii tachyzoites, underscore glutamine is a complement substrate, and provide a basis for understanding the adaptation of T. gondii to diverse host cells.

PubMed: 19617561, full text

Localisation information

TGME49_014320 (GT1) facilitative glucose transporter, putative

Experimental localisation: parasite plasma membrane during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgGT1-HA under the control of the NTPase3 gene promoter localizes in the plasma membrane as confirmed by its colocalization with TgGAP45, a protein adjacent to the inner membrane complex of T. gondii."
  • Microscopy type: Light
  • Microscopy method: HA tag
  • Strain:
  • Gene model mapping comments: inferred from another publication
  • Localisation record: PPM during intracellular tachyzoite
  • Comment: strain information not found

TGME49_023940 (GAP45) hypothetical protein

Experimental localisation: adjacent to the inner membrane complex during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgGT1-HA under the control of the NTPase3 gene promoter localizes in the plasma membrane as confirmed by its colocalization with TgGAP45, a protein adjacent to the inner membrane complex of T. gondii."
  • Microscopy type: Light
  • Microscopy method: antibody
  • Strain:
  • Gene model mapping comments: inferred from another publication
  • Localisation record: adjacent to the inner membrane complex during intracellular tachyzoite
  • Comment: strain information not found

TGME49_057120 (ST1) glucose transporter, putative

Experimental localisation: cytoplasmic structure during intracellular tachyzoite, not parasite plasma membrane during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Yet again, TgST1 and TgST3 were present in intracellular compartments."
  • Microscopy type: Light
  • Microscopy method: C terminal Ty1 tag, N terminal HA tag, Ty1 tag in middle of protein
  • Strain:
  • Gene model mapping comments: blast from EF198053, annotation matches
  • Localisation record: intracellular compartment and not PPM during intracellular tachyzoite
  • Comment: strain information not found

TGME49_072500 (ST2) sugar transporter, putative

Experimental localisation: parasite plasma membrane during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Toxoplasma harbors 3 additional putative sugar transporters (TgST1-3), of which TgST2 is expressed at its surface, whereas TgST1 and TgST3 are intracellular."
  • Microscopy type: Light
  • Microscopy method: C terminal Ty1 tag, N terminal HA tag, Ty1 tag in middle of protein
  • Strain:
  • Gene model mapping comments: blast from EF427938, annotation matches, inconsistent 5' UTR?
  • Localisation record: PPM during intracellular tachyzoite
  • Comment: strain information not found

TGME49_001260 (ST3) sugar transporter, putative

Experimental localisation: cytoplasmic structure during intracellular tachyzoite, not parasite plasma membrane during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Yet again, TgST1 and TgST3 were present in intracellular compartments."
  • Microscopy type: Light
  • Microscopy method: C terminal Ty1 tag, N terminal HA tag, Ty1 tag in middle of protein
  • Strain:
  • Gene model mapping comments: blast from EF427939, inconsistent 5' UTR?
  • Localisation record: intracellular compartment and not PPM during intracellular tachyzoite
  • Comment: strain information not found

TGME49_027280 (GRA3) dense granule protein 3

Experimental localisation: dense granule during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "In contrast, TgST1 and TgST3 were only detected within the parasite, and shown to partially localize with a dense granule protein, TgGRA3."
  • Microscopy type: Light
  • Microscopy method: antibody
  • Strain:
  • Gene model mapping comments: inferred from another publication
  • Localisation record: dense granule during intracellular tachyzoite
  • Comment: strain information not found