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The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite capable of infecting humans and animals. The organism has extraordinary metabolic resilience that allows it to establish parasitism in varied nutritional milieus of diverse host cells. Our earlier work has shown that, despite flexibility in the...

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Autores principales: Lyu, Congcong, Chen, Yukun, Meng, Yanan, Yang, Jichao, Ye, Shu, Niu, Zhipeng, EI-Debs, Issam, Gupta, Nishith, Shen, Bang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10100952/
https://www.ncbi.nlm.nih.gov/pubmed/36920199
http://dx.doi.org/10.1128/spectrum.05043-22
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author Lyu, Congcong
Chen, Yukun
Meng, Yanan
Yang, Jichao
Ye, Shu
Niu, Zhipeng
EI-Debs, Issam
Gupta, Nishith
Shen, Bang
author_facet Lyu, Congcong
Chen, Yukun
Meng, Yanan
Yang, Jichao
Ye, Shu
Niu, Zhipeng
EI-Debs, Issam
Gupta, Nishith
Shen, Bang
author_sort Lyu, Congcong
collection PubMed
description Toxoplasma gondii is an obligate intracellular parasite capable of infecting humans and animals. The organism has extraordinary metabolic resilience that allows it to establish parasitism in varied nutritional milieus of diverse host cells. Our earlier work has shown that, despite flexibility in the usage of glucose and glutamine as the major carbon precursors, the production of pyruvate by glycolytic enzymes is central to the parasite’s growth. Pyruvate is metabolized in a number of subcellular compartments, including the mitochondrion, apicoplast, and cytosol. With the objective of examining the mechanism and importance of the mitochondrial pool of pyruvate imported from the cytosol, we identified the conserved mitochondrial pyruvate carrier (MPC) complex, consisting of two subunits, MPC1 and MPC2, in T. gondii. The two parasite proteins could complement a yeast mutant deficient in growth on leucine and valine. Genetic ablation of either one or both subunits reduced the parasite’s growth, mimicking the deletion of branched-chain ketoacid dehydrogenase (BCKDH), which has been reported to convert pyruvate into acetyl-coenzyme A (CoA) in the mitochondrion. Metabolic labeling of the MPC mutants by isotopic glucose revealed impaired synthesis of acetyl-CoA, correlating with a global decrease in carbon flux through glycolysis and the tricarboxylic acid (TCA) cycle. Disruption of MPC proteins exerted only a modest effect on the parasite’s virulence in mice, further highlighting its metabolic flexibility. In brief, our work reveals the modus operandi of pyruvate transport from the cytosol to the mitochondrion in the parasite, providing the missing link between glycolysis and the TCA cycle in T. gondii. IMPORTANCE T. gondii is a zoonotic parasite capable of infecting many warm-blooded organisms, including humans. Among others, a feature that allows it to parasitize multiple hosts is its exceptional metabolic plasticity. Although T. gondii can utilize different carbon sources, pyruvate homeostasis is critical for parasite growth. Pyruvate is produced primarily in the cytosol but metabolized in other organelles, such as the mitochondrion and apicoplast. The mechanism of import and physiological significance of pyruvate in these organelles remains unclear. Here, we identified the transporter of cytosol-derived pyruvate into the mitochondrion and studied its constituent subunits and their relevance. Our results show that cytosolic pyruvate is a major source of acetyl-CoA in the mitochondrion and that the mitochondrial pyruvate transporter is needed for optimal parasite growth. The mutants lacking the transporter are viable and virulent in a mouse model, underscoring the metabolic plasticity in the parasite’s mitochondrion.
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spelling pubmed-101009522023-04-14 The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii Lyu, Congcong Chen, Yukun Meng, Yanan Yang, Jichao Ye, Shu Niu, Zhipeng EI-Debs, Issam Gupta, Nishith Shen, Bang Microbiol Spectr Research Article Toxoplasma gondii is an obligate intracellular parasite capable of infecting humans and animals. The organism has extraordinary metabolic resilience that allows it to establish parasitism in varied nutritional milieus of diverse host cells. Our earlier work has shown that, despite flexibility in the usage of glucose and glutamine as the major carbon precursors, the production of pyruvate by glycolytic enzymes is central to the parasite’s growth. Pyruvate is metabolized in a number of subcellular compartments, including the mitochondrion, apicoplast, and cytosol. With the objective of examining the mechanism and importance of the mitochondrial pool of pyruvate imported from the cytosol, we identified the conserved mitochondrial pyruvate carrier (MPC) complex, consisting of two subunits, MPC1 and MPC2, in T. gondii. The two parasite proteins could complement a yeast mutant deficient in growth on leucine and valine. Genetic ablation of either one or both subunits reduced the parasite’s growth, mimicking the deletion of branched-chain ketoacid dehydrogenase (BCKDH), which has been reported to convert pyruvate into acetyl-coenzyme A (CoA) in the mitochondrion. Metabolic labeling of the MPC mutants by isotopic glucose revealed impaired synthesis of acetyl-CoA, correlating with a global decrease in carbon flux through glycolysis and the tricarboxylic acid (TCA) cycle. Disruption of MPC proteins exerted only a modest effect on the parasite’s virulence in mice, further highlighting its metabolic flexibility. In brief, our work reveals the modus operandi of pyruvate transport from the cytosol to the mitochondrion in the parasite, providing the missing link between glycolysis and the TCA cycle in T. gondii. IMPORTANCE T. gondii is a zoonotic parasite capable of infecting many warm-blooded organisms, including humans. Among others, a feature that allows it to parasitize multiple hosts is its exceptional metabolic plasticity. Although T. gondii can utilize different carbon sources, pyruvate homeostasis is critical for parasite growth. Pyruvate is produced primarily in the cytosol but metabolized in other organelles, such as the mitochondrion and apicoplast. The mechanism of import and physiological significance of pyruvate in these organelles remains unclear. Here, we identified the transporter of cytosol-derived pyruvate into the mitochondrion and studied its constituent subunits and their relevance. Our results show that cytosolic pyruvate is a major source of acetyl-CoA in the mitochondrion and that the mitochondrial pyruvate transporter is needed for optimal parasite growth. The mutants lacking the transporter are viable and virulent in a mouse model, underscoring the metabolic plasticity in the parasite’s mitochondrion. American Society for Microbiology 2023-03-15 /pmc/articles/PMC10100952/ /pubmed/36920199 http://dx.doi.org/10.1128/spectrum.05043-22 Text en Copyright © 2023 Lyu et al. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Lyu, Congcong
Chen, Yukun
Meng, Yanan
Yang, Jichao
Ye, Shu
Niu, Zhipeng
EI-Debs, Issam
Gupta, Nishith
Shen, Bang
The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title_full The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title_fullStr The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title_full_unstemmed The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title_short The Mitochondrial Pyruvate Carrier Coupling Glycolysis and the Tricarboxylic Acid Cycle Is Required for the Asexual Reproduction of Toxoplasma gondii
title_sort mitochondrial pyruvate carrier coupling glycolysis and the tricarboxylic acid cycle is required for the asexual reproduction of toxoplasma gondii
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10100952/
https://www.ncbi.nlm.nih.gov/pubmed/36920199
http://dx.doi.org/10.1128/spectrum.05043-22
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