The NTP Generating Activity of Pyruvate Kinase II is Critical for Apicoplast Maintenance in Plasmodium falciparum
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ABSTRACT:
PROVIDER: PRJNA563082 | ENA |
REPOSITORIES: ENA
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Project description:The apicoplast of Plasmodium falciparum parasites is believed to rely on the import of three-carbon phosphate compounds for use in organelle anabolic pathways, in addition to the generation of energy and reducing power within the organelle. We generated a series of genetic deletions in an apicoplast metabolic bypass line to determine which genes involved in apicoplast carbon metabolism are required for blood-stage parasite survival and organelle maintenance. We were able to demonstrate that pyruvate kinase II (PyrKII), the sole predicted source of pyruvate and NTPs within the apicoplast, is essential for organelle maintenance. However, deletions within apicoplast pathways that metabolize pyruvate did not result in organelle disruption, indicating that NTPs generated by PyrKII are the products required for this process. Enzymatic characterization of PyrKII revealed that it was active against all NDPs and dNDPs tested with broad substrate specificity, suggesting that it may be capable of generating any and all NTPs and dNTPs within the organelle. Conditional mislocalization of PyrKII resulted in a decrease in transcript levels within the apicoplast that preceded organelle disruption, suggesting that PyrKII is required for organelle maintenance due to its role in nucleotide triphosphate generation within the apicoplast.
2020-07-31 | GSE136688 | GEO
Project description: Not available
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Project description:Repression by PRDM13 is critical for generating precise neuronal identity
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Project description:Pyruvate is a key metabolite in glycolysis and tricarboxylic acid (TCA) cycle. Exogenous pyruvate modulates metabolism, provides cellular protection, and is essential for the maintenance of human preimplantation embryos and human embryonic stem cells (hESCs). However, little is known about how pyruvate contributes to cell fate determination during epiblast stage. In this study, we used hESCs as a model to demonstrate that elevated exogenous pyruvate shifts metabolic balance towards oxidative phosphorylation in both maintenance and differentiation conditions. During differentiation, pyruvate potentiates mesoderm and endoderm lineage specification. Pyruvate production and its mitochondrial metabolism are required in BMP4-induced mesoderm differentiation. However, the TCA cycle metabolites do not have the same effect as pyruvate on differentiation. Further study shows that pyruvate increases AMP/ATP ratio, activates AMPK, and then modulates the mTOR pathway to enhance mesoderm differentiation. This study reveals that exogenous pyruvate not only controls metabolism, but also modulates signaling pathways in hESC differentiation.
2019-05-06 | GSE130249 | GEO
Project description:Pyruvate kinase (Pyk) is a rate-limiting enzyme that catalyzes the final metabolic reaction in glycolysis. The importance of this enzyme, however, extends far beyond ATP production, as Pyk is also known to regulate tissue growth, cell proliferation, and development. Studies of this enzyme in Drosophila melanogaster, however, are complicated by the fact the fly genome encodes six Pyk paralogs and the function of these individual genes remain poorly defined. To address this issue, we used a phylogenetic approach to demonstrate that the gene Pyk encodes the enzyme most similar to the mammalian Pyk orthologs while the other five Drosophila Pyk have significantly diverged from the canonical enzyme. Consistent with this observation, metabolomic studies of two different Pyk mutant backgrounds revealed that larvae lacking Pyk exhibit a severe block in glycolysis, with a buildup of glycolytic intermediates upstream of pyruvate. However, our analysis also unexpectantly reveals that steady state pyruvate levels are unchanged in Pyk mutants, indicating that larval metabolism maintains pyruvate pool size despite severe metabolic limitations. Consistent with our metabolomics findings, a complementary RNAseq analysis revealed that genes involved in lipid metabolism and peptidase activity are elevated in Pyk mutants, again indicating that loss of this glycolytic enzyme induces compensatory changes in other aspects of metabolism. Overall, our study provides both insight towards understanding how Drosophila larval metabolism adapts to disruption of glycolytic metabolism and immediate clinical relevance considering that Pyk deficiency is the most common congenital enzymatic defect in humans.
2023-09-01 | GSE234299 | GEO
Project description:Pyruvate kinase (PK) catalyzes the conversion of phosphoenolpyruvate to pyruvate during glycolysis. The PK isoform PKM2 has additional roles in regulation of gene transcription and protein phosphorylation. PKM2 controls macrophage metabolic remodeling in inflammation, but its role in T cell biology is poorly understood. These results show that TEPP-46, an activator of PKM2, reduces CD4+ T cell activation, proliferation, and cytokine production by inhibiting essential signaling pathways and preventing glycolysis.
2019-11-26 | GSE139378 | GEO
Project description:Recently identified spontaneous mutants of major glucose-PTS (manLMNO) in stocks of Streptococcus sanguinis SK36 showed enhanced fitness in low-pH environment. Transcriptomic and metabolomic analyses of the manL mutant (SK36/manL) revealed redirection of pyruvate from production of lactate to acetate for extra energy extraction, resulting in excretion of greater amounts of pyruvate and H2O2, and increased expression of multiple alkali-generating activities. Genes showing increased expression in SK36/manL also included several carbohydrate transporters, putative extracellular glycosidases, intracellular polysaccharide (IPS) locus, pathways for catabolism of acetoin, ethanolamine, ascorbate, and formate, genes required for membrane biosynthesis, and those for motility and attachment.
2022-07-28 | GSE209672 | GEO
Project description:Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Although the importance of glycolytic and oxidative metabolism in M1 and M2 macrophages, respectively, is well established, our knowledge of metabolic checkpoints controlling these effector states is limited. Here we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the conversion of cytosolic pyruvate to mitochondrial acetyl-CoA by pyruvate dehydrogenase, functions as a metabolic checkpoint in M1 macrophages. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). The therapeutic potential of attenuation of pro-inflammatory responses by PDK inhibition was tested, both genetically and pharmacologically, in obesity-induced insulin resistance, a disease process in which M1 macrophages contribute to adipose tissue inflammation and insulin resistance. Taken together, these studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages.
2019-05-11 | GSE112595 | GEO
Project description:A hallmark of the biofilm architecture is the presence of microcolonies. However, little is known about the underlying mechanisms governing microcolony formation. In the human pathogen Pseudomonas aeruginosa, microcolony formation is dependent on the two-component regulator MifR, with mifR mutant biofilms exhibiting an overall thin structure lacking microcolonies, and overexpression of mifR resulting in hyper-microcolony formation. Here, we made use of the distinct MifR-dependent phenotypes to elucidate mechanisms associated with microcolony formation. Using global transcriptomic and proteomic approaches, we demonstrate that cells located within microcolonies experience stressful, oxygen limited, and energy starving conditions, as indicated by the activation of stress response mechanisms and anaerobic and fermentative processes, in particular pyruvate fermentation. Inactivation of genes involved in pyruvate utilization including uspK, acnA and ldhA abrogated microcolony formation in a manner similar to mifR inactivation. Moreover, depletion of pyruvate from the growth medium impaired biofilm and microcolony formation, while addition of pyruvate significantly increased microcolony formation. Addition of pyruvate partly restored microcolony formation in ∆mifR biofilms. Moreover, addition of pyruvate to or expression of mifR in lactate dehydrogenase (ldhA) mutant biofilms did not restore microcolony formation. Consistent with the finding of denitrification genes not demonstrating distinct expression patterns in biofilms forming or lacking microcolonies, addition of nitrate did not alter microcolony formation. Our findings indicate the fermentative utilization of pyruvate to be a microcolony-specific adaptation to the oxygen limitation and energy starvation of the P. aeruginosa biofilm environment.
2012-05-01 | GSE35286 | GEO
Project description:The transporter which uptakes pyruvate into the mitochondria during pyruvate oxidation, called the Mitochondrial Pyruvate Carrier (MPC), was only recently identified. While the MPC has been studied in a variety of cell types, including cancer cells and stem cells, very little is known about the importance of MPC in immune cells. Here, we delete MPC from hematopoietic cells and measure its impact on T cell gene expression.
2020-04-27 | GSE122711 | GEO