Genetic characterization of glucose transporter function inLeishmania mexicana
- 21 March 2003
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 100 (7) , 3901-3906
- https://doi.org/10.1073/pnas.0630165100
Abstract
Both insect and mammalian life cycle stages of Leishmania mexicana take up glucose and express all three isoforms encoded by the LmGT glucose transporter gene family. To evaluate glucose transporter function in intact parasites, a null mutant line has been created by targeted disruption of the LmGT locus that encompasses the LmGT1, LmGT2, and LmGT3 genes. This deltalmgt null mutant exhibited no detectable glucose transport activity. The growth rate of the deltalmgt knockout in the promastigote stage was reduced to a rate comparable with that of WT cells grown in the absence of glucose. deltalmgt cells also exhibited dramatically reduced infectivity to macrophages, demonstrating that expression of LmGT isoforms is essential for viability of amastigotes. Furthermore, WT L. mexicana were not able to grow as axenic culture form amastigotes if glucose was withdrawn from the medium, implying that glucose is an essential nutrient in this life cycle stage. Expression of either LmGT2 or LmGT3, but not of LmGT1, in deltalmgt null mutants significantly restored growth as promastigotes, but only LmGT3 expression substantially rescued amastigote growth in macrophages. Subcellular localization of the three isoforms was investigated in deltalmgt cells expressing individual LmGT isoforms. Using anti-LmGT antiserum and GFP-tagged LmGT fusion proteins, LmGT2 and LmGT3 were localized to the cell body, whereas LmGT1 was localized specifically to the flagellum. These results establish that each glucose transporter isoform has distinct biological functions in the parasite.Keywords
This publication has 45 references indexed in Scilit:
- Metabolic Aspects of Glycosomes in Trypanosomatidae – New Data and ViewsParasitology Today, 2000
- Four Conserved Cytoplasmic Sequence Motifs Are Important for Transport Function of the LeishmaniaInositol/H+ SymporterPublished by Elsevier ,2000
- Two glucose transporters in Saccharomyces cerevisiae are glucose sensors that generate a signal for induction of gene expression.Proceedings of the National Academy of Sciences, 1996
- Glucose transport in amastigotes and promastigotes of Leishmania mexicana mexicanaMolecular and Biochemical Parasitology, 1995
- Sugars in the alimentary canal of Lutzomyia youngi (Diptera: Phlebotominae)Medical and Veterinary Entomology, 1994
- Two more independent selectable markers for stable transfection of LeishmaniaMolecular and Biochemical Parasitology, 1993
- Glucose and proline transport in kinetoplastidsParasitology Today, 1993
- Sandfly diet and LeishmaniaParasitology Today, 1986
- Enhanced Metabolism of Leishmania donovani Amastigotes at Acid p H: an Adaptation for Intracellular GrowthScience, 1985
- Human Cutaneous Leishmania in a Mouse Macrophage Line: Propagation and Isolation of Intracellular ParasitesScience, 1980