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

Martin Blume, Dayana Rodriguez-Contreras, Scott Landfear, Tobias Fleige, Dominique Soldati-Favre, Richard Lucius, Nishith Gupta

Research output: Contribution to journalArticlepeer-review

106 Scopus citations


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 Δtgst2, the modest impairment in Δtggt1 and Δtggt1/ Δtgst2 mutants is because of a minor delay in their intracellular replication, which is a direct consequence of the abolished import of glucose. The Δtggt1 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 Δtggt1 culture fails to accentuate its intrinsic growth defect and prompts it to procure glutamine to sustain its metabolism. Unexpectedly, in vivo virulence of Δtggt1 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.

Original languageEnglish (US)
Pages (from-to)12998-13003
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number31
StatePublished - Aug 4 2009


  • Genetic manipulation
  • Glucose transport
  • Glutamine metabolism

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Host-derived glucose and its transporter in the obligate intracellular pathogen Toxoplasma gondii are dispensable by glutaminolysis'. Together they form a unique fingerprint.

Cite this