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Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth
Many apicomplexan parasites harbor a non-photosynthetic plastid called the apicoplast, which hosts important metabolic pathways like the methylerythritol 4-phosphate (MEP) pathway that synthesizes isoprenoid precursors. Yet many details in apicoplast metabolism are not well understood. In this study...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9744290/ https://www.ncbi.nlm.nih.gov/pubmed/36449552 http://dx.doi.org/10.1371/journal.ppat.1011009 |
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author | Niu, Zhipeng Ye, Shu Liu, Jiaojiao Lyu, Mengyu Xue, Lilan Li, Muxiao Lyu, Congcong Zhao, Junlong Shen, Bang |
author_facet | Niu, Zhipeng Ye, Shu Liu, Jiaojiao Lyu, Mengyu Xue, Lilan Li, Muxiao Lyu, Congcong Zhao, Junlong Shen, Bang |
author_sort | Niu, Zhipeng |
collection | PubMed |
description | Many apicomplexan parasites harbor a non-photosynthetic plastid called the apicoplast, which hosts important metabolic pathways like the methylerythritol 4-phosphate (MEP) pathway that synthesizes isoprenoid precursors. Yet many details in apicoplast metabolism are not well understood. In this study, we examined the physiological roles of four glycolytic enzymes in the apicoplast of Toxoplasma gondii. Many glycolytic enzymes in T. gondii have two or more isoforms. Endogenous tagging each of these enzymes found that four of them were localized to the apicoplast, including pyruvate kinase2 (PYK2), phosphoglycerate kinase 2 (PGK2), triosephosphate isomerase 2 (TPI2) and phosphoglyceraldehyde dehydrogenase 2 (GAPDH2). The ATP generating enzymes PYK2 and PGK2 were thought to be the main energy source of the apicoplast. Surprisingly, deleting PYK2 and PGK2 individually or simultaneously did not cause major defects on parasite growth or virulence. In contrast, TPI2 and GAPDH2 are critical for tachyzoite proliferation. Conditional depletion of TPI2 caused significant reduction in the levels of MEP pathway intermediates and led to parasite growth arrest. Reconstitution of another isoprenoid precursor synthesis pathway called the mevalonate pathway in the TPI2 depletion mutant partially rescued its growth defects. Similarly, knocking down the GAPDH2 enzyme that produces NADPH also reduced isoprenoid precursor synthesis through the MEP pathway and inhibited parasite proliferation. In addition, it reduced de novo fatty acid synthesis in the apicoplast. Together, these data suggest a model that the apicoplast dwelling TPI2 provides carbon source for the synthesis of isoprenoid precursor, whereas GAPDH2 supplies reducing power for pathways like MEP, fatty acid synthesis and ferredoxin redox system in T. gondii. As such, both enzymes are critical for parasite growth and serve as potential targets for anti-toxoplasmic intervention designs. On the other hand, the dispensability of PYK2 and PGK2 suggest additional sources for energy in the apicoplast, which deserves further investigation. |
format | Online Article Text |
id | pubmed-9744290 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-97442902022-12-13 Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth Niu, Zhipeng Ye, Shu Liu, Jiaojiao Lyu, Mengyu Xue, Lilan Li, Muxiao Lyu, Congcong Zhao, Junlong Shen, Bang PLoS Pathog Research Article Many apicomplexan parasites harbor a non-photosynthetic plastid called the apicoplast, which hosts important metabolic pathways like the methylerythritol 4-phosphate (MEP) pathway that synthesizes isoprenoid precursors. Yet many details in apicoplast metabolism are not well understood. In this study, we examined the physiological roles of four glycolytic enzymes in the apicoplast of Toxoplasma gondii. Many glycolytic enzymes in T. gondii have two or more isoforms. Endogenous tagging each of these enzymes found that four of them were localized to the apicoplast, including pyruvate kinase2 (PYK2), phosphoglycerate kinase 2 (PGK2), triosephosphate isomerase 2 (TPI2) and phosphoglyceraldehyde dehydrogenase 2 (GAPDH2). The ATP generating enzymes PYK2 and PGK2 were thought to be the main energy source of the apicoplast. Surprisingly, deleting PYK2 and PGK2 individually or simultaneously did not cause major defects on parasite growth or virulence. In contrast, TPI2 and GAPDH2 are critical for tachyzoite proliferation. Conditional depletion of TPI2 caused significant reduction in the levels of MEP pathway intermediates and led to parasite growth arrest. Reconstitution of another isoprenoid precursor synthesis pathway called the mevalonate pathway in the TPI2 depletion mutant partially rescued its growth defects. Similarly, knocking down the GAPDH2 enzyme that produces NADPH also reduced isoprenoid precursor synthesis through the MEP pathway and inhibited parasite proliferation. In addition, it reduced de novo fatty acid synthesis in the apicoplast. Together, these data suggest a model that the apicoplast dwelling TPI2 provides carbon source for the synthesis of isoprenoid precursor, whereas GAPDH2 supplies reducing power for pathways like MEP, fatty acid synthesis and ferredoxin redox system in T. gondii. As such, both enzymes are critical for parasite growth and serve as potential targets for anti-toxoplasmic intervention designs. On the other hand, the dispensability of PYK2 and PGK2 suggest additional sources for energy in the apicoplast, which deserves further investigation. Public Library of Science 2022-11-30 /pmc/articles/PMC9744290/ /pubmed/36449552 http://dx.doi.org/10.1371/journal.ppat.1011009 Text en © 2022 Niu et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Niu, Zhipeng Ye, Shu Liu, Jiaojiao Lyu, Mengyu Xue, Lilan Li, Muxiao Lyu, Congcong Zhao, Junlong Shen, Bang Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title | Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title_full | Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title_fullStr | Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title_full_unstemmed | Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title_short | Two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for Toxoplasma growth |
title_sort | two apicoplast dwelling glycolytic enzymes provide key substrates for metabolic pathways in the apicoplast and are critical for toxoplasma growth |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9744290/ https://www.ncbi.nlm.nih.gov/pubmed/36449552 http://dx.doi.org/10.1371/journal.ppat.1011009 |
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