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Luo D, Bai Z, Bai H, Liu N, Han J, Ma C, Wu D, Bai L, Li Z. A first-in-class dimethyl 2-acetamido terephthalate inhibitor targeting Conyza canadensis SHMT1 with a novel herbicidal mode-of-action. J Adv Res 2023:S2090-1232(23)00295-3. [PMID: 37820886 DOI: 10.1016/j.jare.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 09/26/2023] [Accepted: 10/04/2023] [Indexed: 10/13/2023] Open
Abstract
INTRODUCTION Herbicide application is a highly efficiency method of weed control that boots agricultural output and assures food security. The development of novel herbicides focuses on improved bioactivity and new modes of action. The amino acid biosynthesis was validated as a promising novel mode of action for herbicidal compounds. However, the amino acid biosynthesis enzyme remains largely unexplored for herbicidal targets. OBJECTIVES Serine hydroxymethyl transferase (SHMT) is an essentialenzyme in the photorespiratory cycle. The study aims to explore Conyza canadensis SHMT1 (CcSHMT1) as a promising target for herbicide discovery. METHODS Structure determination of CcSHMT1 was resolved by X-ray crystallography. Virtual screening docking experiments were performed with Glide version 5.5. Novel derivatives of dimethyl 2-acetamido terephthalate were further designed, synthesized, and bioassay. The druggability of the inhibitor was evidenced by ultrastructural changes in mitochondria, in vivo and vitro enzyme activity assays, and genetics analysis. RESULTS CcSHMT1 has a typical PLP-dependent enzyme 3D structure. The dimethyl 2-acetamido terephthalate-containing compounds had herbicidal activity. Dimethyl 2-(2-(4-(2-(4-bromo-2-chlorophenoxy) acetyl)piperazin-1-yl)acetamido) terephthalate (Compound 9ay, EC50 = 193.8 g a.i./ ha) exhibited the highest herbicidal activity on tested weed among the synthesized compounds. Compound 9ay had no obvious adverse effect on the growth of maize and honeybees. Compound 9ay was verified to target CcSHMT1 as an herbicide candidate. CONCLUSION A first-in-class CcSHMT1 inhibitor that could be developed as a potent herbicide with a new mode of action and provide an avenue for discovering novel inhibitors of pyridoxal-5-phosphate-dependent enzymes.
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Affiliation(s)
- Dingfeng Luo
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China
| | - Zhendong Bai
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China
| | - Haodong Bai
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China
| | - Na Liu
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China
| | - Jincai Han
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China
| | - Changsheng Ma
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China
| | - Di Wu
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China
| | - Lianyang Bai
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China.
| | - Zuren Li
- Hunan Provincial Key Laboratory for Biology and Control of Weeds, Hunan Academy of Agricultural Sciences, Changsha 410125, China; Longping Branch, College of Biology, Hunan University, Changsha 410125, China.
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Swift RP, Elahi R, Rajaram K, Liu HB, Prigge ST. The Plasmodium falciparum apicoplast cysteine desulfurase provides sulfur for both iron-sulfur cluster assembly and tRNA modification. eLife 2023; 12:e84491. [PMID: 37166116 PMCID: PMC10219651 DOI: 10.7554/elife.84491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/10/2023] [Indexed: 05/12/2023] Open
Abstract
Iron-sulfur clusters (FeS) are ancient and ubiquitous protein cofactors that play fundamental roles in many aspects of cell biology. These cofactors cannot be scavenged or trafficked within a cell and thus must be synthesized in any subcellular compartment where they are required. We examined the FeS synthesis proteins found in the relict plastid organelle, called the apicoplast, of the human malaria parasite Plasmodium falciparum. Using a chemical bypass method, we deleted four of the FeS pathway proteins involved in sulfur acquisition and cluster assembly and demonstrated that they are all essential for parasite survival. However, the effect that these deletions had on the apicoplast organelle differed. Deletion of the cysteine desulfurase SufS led to disruption of the apicoplast organelle and loss of the organellar genome, whereas the other deletions did not affect organelle maintenance. Ultimately, we discovered that the requirement of SufS for organelle maintenance is not driven by its role in FeS biosynthesis, but rather, by its function in generating sulfur for use by MnmA, a tRNA modifying enzyme that we localized to the apicoplast. Complementation of MnmA and SufS activity with a bacterial MnmA and its cognate cysteine desulfurase strongly suggests that the parasite SufS provides sulfur for both FeS biosynthesis and tRNA modification in the apicoplast. The dual role of parasite SufS is likely to be found in other plastid-containing organisms and highlights the central role of this enzyme in plastid biology.
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Affiliation(s)
- Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins UniversityBaltimoreUnited States
- The Johns Hopkins Malaria Research InstituteBaltimoreUnited States
| | - Rubayet Elahi
- Department of Molecular Microbiology and Immunology, Johns Hopkins UniversityBaltimoreUnited States
- The Johns Hopkins Malaria Research InstituteBaltimoreUnited States
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins UniversityBaltimoreUnited States
- The Johns Hopkins Malaria Research InstituteBaltimoreUnited States
| | - Hans B Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins UniversityBaltimoreUnited States
- The Johns Hopkins Malaria Research InstituteBaltimoreUnited States
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins UniversityBaltimoreUnited States
- The Johns Hopkins Malaria Research InstituteBaltimoreUnited States
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Nair SC, Munro JT, Mann A, Llinás M, Prigge ST. The mitochondrion of Plasmodium falciparum is required for cellular acetyl-CoA metabolism and protein acetylation. Proc Natl Acad Sci U S A 2023; 120:e2210929120. [PMID: 37068227 PMCID: PMC10151609 DOI: 10.1073/pnas.2210929120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 02/28/2023] [Indexed: 04/19/2023] Open
Abstract
Coenzyme A (CoA) biosynthesis is an excellent target for antimalarial intervention. While most studies have focused on the use of CoA to produce acetyl-CoA in the apicoplast and the cytosol of malaria parasites, mitochondrial acetyl-CoA production is less well understood. In the current study, we performed metabolite-labeling experiments to measure endogenous metabolites in Plasmodium falciparum lines with genetic deletions affecting mitochondrial dehydrogenase activity. Our results show that the mitochondrion is required for cellular acetyl-CoA biosynthesis and identify a synthetic lethal relationship between the two main ketoacid dehydrogenase enzymes. The activity of these enzymes is dependent on the lipoate attachment enzyme LipL2, which is essential for parasite survival solely based on its role in supporting acetyl-CoA metabolism. We also find that acetyl-CoA produced in the mitochondrion is essential for the acetylation of histones and other proteins outside of the mitochondrion. Taken together, our results demonstrate that the mitochondrion is required for cellular acetyl-CoA metabolism and protein acetylation essential for parasite survival.
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Affiliation(s)
- Sethu C. Nair
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21218
| | - Justin T. Munro
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA16802
| | - Alexis Mann
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21218
| | - Manuel Llinás
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA16802
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA16802
| | - Sean T. Prigge
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21218
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Rajaram K, Tewari SG, Wallqvist A, Prigge ST. Metabolic changes accompanying the loss of fumarate hydratase and malate-quinone oxidoreductase in the asexual blood stage of Plasmodium falciparum. J Biol Chem 2022; 298:101897. [PMID: 35398098 PMCID: PMC9118666 DOI: 10.1016/j.jbc.2022.101897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 12/03/2022] Open
Abstract
In the glucose-rich milieu of red blood cells, asexually replicating malarial parasites mainly rely on glycolysis for ATP production, with limited carbon flux through the mitochondrial tricarboxylic acid (TCA) cycle. By contrast, gametocytes and mosquito-stage parasites exhibit an increased dependence on the TCA cycle and oxidative phosphorylation for more economical energy generation. Prior genetic studies supported these stage-specific metabolic preferences by revealing that six of eight TCA cycle enzymes are completely dispensable during the asexual blood stages of Plasmodium falciparum, with only fumarate hydratase (FH) and malate-quinone oxidoreductase (MQO) being refractory to deletion. Several hypotheses have been put forth to explain the possible essentiality of FH and MQO, including their participation in a malate shuttle between the mitochondrial matrix and the cytosol. However, using newer genetic techniques like CRISPR and dimerizable Cre, we were able to generate deletion strains of FH and MQO in P. falciparum. We employed metabolomic analyses to characterize a double knockout mutant of FH and MQO (ΔFM) and identified changes in purine salvage and urea cycle metabolism that may help to limit fumarate accumulation. Correspondingly, we found that the ΔFM mutant was more sensitive to exogenous fumarate, which is known to cause toxicity by modifying and inactivating proteins and metabolites. Overall, our data indicate that P. falciparum is able to adequately compensate for the loss of FH and MQO, rendering them unsuitable targets for drug development.
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Affiliation(s)
- Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Shivendra G Tewari
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, Maryland, USA
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, Maryland, USA.
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Swift RP, Rajaram K, Liu HB, Prigge ST. Dephospho-CoA kinase, a nuclear-encoded apicoplast protein, remains active and essential after Plasmodium falciparum apicoplast disruption. EMBO J 2021; 40:e107247. [PMID: 34031901 PMCID: PMC8365264 DOI: 10.15252/embj.2020107247] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/06/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022] Open
Abstract
Malaria parasites contain an essential organelle called the apicoplast that houses metabolic pathways for fatty acid, heme, isoprenoid, and iron–sulfur cluster synthesis. Surprisingly, malaria parasites can survive without the apicoplast as long as the isoprenoid precursor isopentenyl pyrophosphate (IPP) is supplemented in the growth medium, making it appear that isoprenoid synthesis is the only essential function of the organelle in blood‐stage parasites. In the work described here, we localized an enzyme responsible for coenzyme A synthesis, DPCK, to the apicoplast, but we were unable to delete DPCK, even in the presence of IPP. However, once the endogenous DPCK was complemented with the E. coli DPCK (EcDPCK), we were successful in deleting it. We were then able to show that DPCK activity is required for parasite survival through knockdown of the complemented EcDPCK. Additionally, we showed that DPCK enzyme activity remains functional and essential within the vesicles present after apicoplast disruption. These results demonstrate that while the apicoplast of blood‐stage P. falciparum parasites can be disrupted, the resulting vesicles remain biochemically active and are capable of fulfilling essential functions.
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Affiliation(s)
- Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Hans B Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Abstract
Ferredoxin (Fd) and ferredoxin-NADP+ reductase (FNR) form a redox system that is hypothesized to play a central role in the maintenance and function of the apicoplast organelle of malaria parasites. The Fd/FNR system provides reducing power to various iron-sulfur cluster (FeS)-dependent proteins in the apicoplast and is believed to help to maintain redox balance in the organelle. While the Fd/FNR system has been pursued as a target for antimalarial drug discovery, Fd, FNR, and the FeS proteins presumably reliant on their reducing power play an unknown role in parasite survival and apicoplast maintenance. To address these questions, we generated genetic deletions of these proteins in a parasite line containing an apicoplast bypass system. Through these deletions, we discovered that Fd, FNR, and certain FeS proteins are essential for parasite survival but found that none are required for apicoplast maintenance. Additionally, we addressed the question of how Fd and its downstream FeS proteins obtain FeS cofactors by deleting the FeS transfer proteins SufA and NfuApi. While individual deletions of these proteins revealed their dispensability, double deletion resulted in synthetic lethality, demonstrating a redundant role in providing FeS clusters to Fd and other essential FeS proteins. Our data support a model in which the reducing power from the Fd/FNR system to certain downstream FeS proteins is essential for the survival of blood-stage malaria parasites but not for organelle maintenance, while other FeS proteins are dispensable for this stage of parasite development. IMPORTANCE Ferredoxin (Fd) and ferredoxin-NADP+ reductase (FNR) form one of the few known redox systems in the apicoplast of malaria parasites and provide reducing power to iron-sulfur (FeS) cluster proteins within the organelle. While the Fd/FNR system has been explored as a drug target, the essentiality and roles of this system and the identity of its downstream FeS proteins have not been determined. To answer these questions, we generated deletions of these proteins in an apicoplast metabolic bypass line (PfMev) and determined the minimal set of proteins required for parasite survival. Moving upstream of this pathway, we also generated individual and dual deletions of the two FeS transfer proteins that deliver FeS clusters to Fd and downstream FeS proteins. We found that both transfer proteins are dispensable, but double deletion displayed a synthetic lethal phenotype, demonstrating their functional redundancy. These findings provide important insights into apicoplast biochemistry and drug development.
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Swift RP, Rajaram K, Keutcha C, Liu HB, Kwan B, Dziedzic A, Jedlicka AE, Prigge ST. The NTP generating activity of pyruvate kinase II is critical for apicoplast maintenance in Plasmodium falciparum. eLife 2020; 9:e50807. [PMID: 32815516 PMCID: PMC7556864 DOI: 10.7554/elife.50807] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 08/20/2020] [Indexed: 12/20/2022] Open
Abstract
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 found that pyruvate kinase II (PyrKII) is essential for organelle maintenance, but that production of pyruvate by PyrKII is not responsible for this phenomenon. Enzymatic characterization of PyrKII revealed activity against all NDPs and dNDPs tested, suggesting that it may be capable of generating a broad range of nucleotide triphosphates. Conditional mislocalization of PyrKII resulted in decreased 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.
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Affiliation(s)
- Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Cyrianne Keutcha
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Hans B Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Bobby Kwan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Amanda Dziedzic
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Anne E Jedlicka
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
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Swift RP, Rajaram K, Liu HB, Dziedzic A, Jedlicka AE, Roberts AD, Matthews KA, Jhun H, Bumpus NN, Tewari SG, Wallqvist A, Prigge ST. A mevalonate bypass system facilitates elucidation of plastid biology in malaria parasites. PLoS Pathog 2020; 16:e1008316. [PMID: 32059044 PMCID: PMC7046295 DOI: 10.1371/journal.ppat.1008316] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 02/27/2020] [Accepted: 01/10/2020] [Indexed: 12/03/2022] Open
Abstract
Malaria parasites rely on a plastid organelle for survival during the blood stages of infection. However, the entire organelle is dispensable as long as the isoprenoid precursor, isopentenyl pyrophosphate (IPP), is supplemented in the culture medium. We engineered parasites to produce isoprenoid precursors from a mevalonate-dependent pathway, creating a parasite line that replicates normally after the loss of the apicoplast organelle. We show that carbon-labeled mevalonate is specifically incorporated into isoprenoid products, opening new avenues for researching this essential class of metabolites in malaria parasites. We also show that essential apicoplast proteins, such as the enzyme target of the drug fosmidomycin, can be deleted in this mevalonate bypass parasite line, providing a new method to determine the roles of other important apicoplast-resident proteins. Several antibacterial drugs kill malaria parasites by targeting basic processes, such as transcription, in the organelle. We used metabolomic and transcriptomic methods to characterize parasite metabolism after azithromycin treatment triggered loss of the apicoplast and found that parasite metabolism and the production of apicoplast proteins is largely unaltered. These results provide insight into the effects of apicoplast-disrupting drugs, several of which have been used to treat malaria infections in humans. Overall, the mevalonate bypass system provides a way to probe essential aspects of apicoplast biology and study the effects of drugs that target apicoplast processes. Malaria parasites rely on an organelle called the apicoplast for growth and survival. Antimalarial drugs such as azithromycin inhibit basic processes in the apicoplast and result in the disruption of the organelle. Surprisingly, addition of a single metabolite, isopentenyl pyrophosphate (IPP), allows the parasites to survive in culture after disruption of the apicoplast. Unfortunately, using IPP to study this phenomenon has several limitations: IPP is prohibitively expensive, has to be used at high concentrations, and has a half-life less than 5 hours. To address these problems, we engineered parasites to express four enzymes from an alternative pathway capable of producing IPP in the parasites. We validated this new system and used it to metabolically label essential metabolites, to delete an essential apicoplast protein, and to characterize the state of apicoplast-disrupted parasites. A key finding from these studies comes from transcriptomic and metabolomic analysis of parasites treated with the drug azithromycin. We found that apicoplast disruption results in few changes in parasite metabolism. In particular, the expression of hundreds of nuclear-encoded apicoplast proteins are not affected by disruption of the apicoplast organelle, making it likely that apicoplast metabolic pathways and processes are still functional in apicoplast-disrupted parasites.
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Affiliation(s)
- Russell P. Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Hans B. Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Amanda Dziedzic
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Anne E. Jedlicka
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Aleah D. Roberts
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Krista A. Matthews
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Hugo Jhun
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Namandje N. Bumpus
- Department of Medicine (Division of Clinical Pharmacology), Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shivendra G. Tewari
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, United States of America
| | - Sean T. Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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McLean KJ, Straimer J, Hopp CS, Vega-Rodriguez J, Small-Saunders JL, Kanatani S, Tripathi A, Mlambo G, Dumoulin PC, Harris CT, Tong X, Shears MJ, Ankarklev J, Kafsack BFC, Fidock DA, Sinnis P. Generation of Transmission-Competent Human Malaria Parasites with Chromosomally-Integrated Fluorescent Reporters. Sci Rep 2019; 9:13131. [PMID: 31511546 PMCID: PMC6739413 DOI: 10.1038/s41598-019-49348-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 08/15/2019] [Indexed: 01/01/2023] Open
Abstract
Malaria parasites have a complex life cycle that includes specialized stages for transmission between their mosquito and human hosts. These stages are an understudied part of the lifecycle yet targeting them is an essential component of the effort to shrink the malaria map. The human parasite Plasmodium falciparum is responsible for the majority of deaths due to malaria. Our goal was to generate transgenic P. falciparum lines that could complete the lifecycle and produce fluorescent transmission stages for more in-depth and high-throughput studies. Using zinc-finger nuclease technology to engineer an integration site, we generated three transgenic P. falciparum lines in which tdtomato or gfp were stably integrated into the genome. Expression was driven by either stage-specific peg4 and csp promoters or the constitutive ef1a promoter. Phenotypic characterization of these lines demonstrates that they complete the life cycle with high infection rates and give rise to fluorescent mosquito stages. The transmission stages are sufficiently bright for intra-vital imaging, flow cytometry and scalable screening of chemical inhibitors and inhibitory antibodies.
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Affiliation(s)
- Kyle Jarrod McLean
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Judith Straimer
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Novartis Institutes for Biomedical Research, Novartis Institute for Tropical Diseases, Emeryville, CA, 94608, USA
| | - Christine S Hopp
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Joel Vega-Rodriguez
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20892, USA
| | - Jennifer L Small-Saunders
- Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Sachie Kanatani
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Abhai Tripathi
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Godfree Mlambo
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Peter C Dumoulin
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, 02115, USA
| | - Chantal T Harris
- Department of Microbiology and Immunology, Weill Cornell School of Medicine, New York, NY, 10065, USA
| | - Xinran Tong
- Department of Microbiology and Immunology, Weill Cornell School of Medicine, New York, NY, 10065, USA
| | - Melanie J Shears
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, 98109, USA
| | - Johan Ankarklev
- Department of Microbiology and Immunology, Weill Cornell School of Medicine, New York, NY, 10065, USA
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Björn F C Kafsack
- Department of Microbiology and Immunology, Weill Cornell School of Medicine, New York, NY, 10065, USA
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA.
| | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
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Roberts AD, Nair SC, Guerra AJ, Prigge ST. Development of a conditional localization approach to control apicoplast protein trafficking in malaria parasites. Traffic 2019; 20:571-582. [PMID: 31094037 DOI: 10.1111/tra.12656] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 01/24/2023]
Abstract
Secretory proteins are of particular importance to apicomplexan parasites and comprise over 15% of the genomes of the human pathogens that cause diseases like malaria, toxoplasmosis and babesiosis as well as other diseases of agricultural significance. Here, we developed an approach that allows us to control the trafficking destination of secretory proteins in the human malaria parasite Plasmodium falciparum. Based on the unique structural requirements of apicoplast transit peptides, we designed three conditional localization domains (CLD1, 2 and 3) that can be used to control protein trafficking via the addition of a cell permeant ligand. Studies comparing the trafficking dynamics of each CLD show that CLD2 has the most optimal trafficking efficiency. To validate this system, we tested whether CLD2 could conditionally localize a biotin ligase called holocarboxylase synthetase 1 (HCS1) without interfering with the function of the enzyme. In a parasite line expressing CLD2-HCS1, we were able to control protein biotinylation in the apicoplast in a ligand-dependent manner, demonstrating the full functionality of the CLD tool. We have developed and validated a novel molecular tool that may be used in future studies to help elucidate the function of secretory proteins in malaria parasites.
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Affiliation(s)
- Aleah D Roberts
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Sethu C Nair
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Alfredo J Guerra
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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11
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Zhuang H, Wu F, Wei W, Dang Y, Yang B, Ma X, Han F, Li Y. Glycine decarboxylase induces autophagy and is downregulated by miRNA-30d-5p in hepatocellular carcinoma. Cell Death Dis 2019; 10:192. [PMID: 30804330 PMCID: PMC6389915 DOI: 10.1038/s41419-019-1446-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 02/07/2023]
Abstract
Glycine decarboxylase (GLDC) belongs to the glycine cleavage system and is involved in one-carbon metabolism. We previously reported that GLDC downregulation enhances hepatocellular carcinoma (HCC) progression and intrahepatic metastasis through decreasing ROS-mediated ubiquitination of cofilin. The role of autophagy in cancer metastasis is still controversial. Redox-dependent autophagy largely relies on the magnitude and the rate of ROS generation. Thus, we aimed to explore the role of GLDC in cellular autophagy during HCC progression. We showed that a high GLDC expression level is associated with better overall survival and is an independent factor for the favorable prognosis of HCC patients. GLDC overexpression significantly induced cell autophagy, whereas GLDC downregulation reduced cell autophagy. Of note, GLDC is the post-transcriptional target of miR-30d-5p. GLDC overexpression could rescue miR-30d-5p-mediated cell metastasis and increase autophagy. Furthermore, upregulation of GLDC could significantly decrease p62 expression and impair intrahepatic metastasis in vivo. Taken together, our results suggest that GLDC may play an important role to increasing miR-30d-5p-reduced autophagy to suppress HCC progress.
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Affiliation(s)
- Hao Zhuang
- Department of Hepatic Biliary Pancreatic Surgery, Cancer Hospital Affiliated to Zhengzhou University, Zhengzhou, 450000, Henan Province, China.,Department of Pathogen Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Fei Wu
- Department of Pathogen Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Wen Wei
- School of Life Sciences, Chongqing University, 400044, Chongqing, China
| | - Yamei Dang
- Department of Pathogen Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Baicai Yang
- Department of Gynaecology and Obstetrics, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang Province, China
| | - Xuda Ma
- Department of Pathogen Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Feng Han
- Department of Hepatic Biliary Pancreatic Surgery, Cancer Hospital Affiliated to Zhengzhou University, Zhengzhou, 450000, Henan Province, China.
| | - Yongmei Li
- Department of Pathogen Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
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12
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Using Lipoamidase as a Novel Probe To Interrogate the Importance of Lipoylation in Plasmodium falciparum. mBio 2018; 9:mBio.01872-18. [PMID: 30459194 PMCID: PMC6247088 DOI: 10.1128/mbio.01872-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipoate is an essential cofactor for a small number of enzymes that are important for central metabolism. Malaria parasites require lipoate scavenged from the human host for growth and survival; however, it is not known why this cofactor is so important. To address this question, we designed a probe of lipoate activity based on the bacterial enzyme lipoamidase (Lpa). Expression of this probe in different subcellular locations allowed us to define the mitochondrion as the compartment housing essential lipoate metabolism. To gain further insight into the specific uses of lipoate in the mitochondrion, we designed a series of catalytically attenuated probes and employed the probes in conjunction with a chemical bypass system. These studies suggest that two lipoylated proteins are required for parasite survival. We were able to express Lpa with different catalytic abilities in different subcellular compartments and driven by different promoters, demonstrating the versatility of this tool and suggesting that it can be used as a probe of lipoate metabolism in other organisms. Lipoate is a redox active cofactor that is covalently bound to key enzymes of oxidative metabolism. Plasmodium falciparum is auxotrophic for lipoate during the intraerythrocytic stages, but it is not known whether lipoate attachment to protein is required or whether attachment is required in a specific subcellular compartment of the parasite. To address these questions, we used an enzyme called lipoamidase (Lpa) as a probe of lipoate metabolism. Lpa was first described in Enterococcus faecalis, and it specifically cleaves protein-bound lipoate, inactivating enzymes requiring this cofactor. Enzymatically active Lpa could be expressed in the cytosol of P. falciparum without any effect on protein lipoylation or parasite growth. Similarly, Lpa could be expressed in the apicoplast, and although protein lipoylation was reduced, parasite growth was not inhibited. By contrast, while an inactive mutant of Lpa could be expressed in the mitochondrion, the active enzyme could not. We designed an attenuated mutant of Lpa and found that this enzyme could be expressed in the parasite mitochondrion, but only in conjunction with a chemical bypass system. These studies suggest that acetyl-CoA production and a cryptic function of the H protein are both required for parasite survival. Our study validates Lpa as a novel probe of metabolism that can be used in other systems and provides new insight into key aspects of mitochondrial metabolism that are responsible for lipoate auxotrophy in malaria parasites.
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13
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Abstract
Malaria parasites require certain host nutrients for growth and survival. In this project, we examined the role of the human vitamin biotin in all stages of the malaria life cycle. We cultured blood- and liver-stage malaria parasites in the absence of biotin and found that, whereas blood-stage replication was unaffected, liver-stage parasites deprived of biotin were no longer capable of establishing a blood-stage infection. Interestingly, biotin depletion resulted in more severe developmental defects than the genetic disruption of parasite biotin metabolism. This finding suggests that host biotin metabolism also contributes to parasite development. Because neither the parasite nor the human host can synthesize biotin, parasite infectivity may be affected by the nutritional status of the host. Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme that is the target of several classes of herbicides. Malaria parasites contain a plant-like ACC, and this is the only protein predicted to be biotinylated in the parasite. We found that ACC is expressed in the apicoplast organelle in liver- and blood-stage malaria parasites; however, it is activated through biotinylation only in the liver stages. Consistent with this observation, deletion of the biotin ligase responsible for ACC biotinylation does not impede blood-stage growth, but results in late liver-stage developmental defects. Biotin depletion increases the severity of the developmental defects, demonstrating that parasite and host biotin metabolism are required for normal liver-stage progression. This finding may link the development of liver-stage malaria parasites to the nutritional status of the host, as neither the parasite nor the human host can synthesize biotin.
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14
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Gisselberg JE, Herrera Z, Orchard LM, Llinás M, Yeh E. Specific Inhibition of the Bifunctional Farnesyl/Geranylgeranyl Diphosphate Synthase in Malaria Parasites via a New Small-Molecule Binding Site. Cell Chem Biol 2017; 25:185-193.e5. [PMID: 29276048 DOI: 10.1016/j.chembiol.2017.11.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/24/2017] [Accepted: 11/22/2017] [Indexed: 12/19/2022]
Abstract
The bifunctional farnesyl/geranylgeranyl diphosphate synthase (FPPS/GGPPS) is a key branchpoint enzyme in isoprenoid biosynthesis in Plasmodium falciparum (malaria) parasites. PfFPPS/GGPPS is a validated, high-priority antimalarial drug target. Unfortunately, current bisphosphonate drugs that inhibit FPPS and GGPPS enzymes by acting as a diphosphate substrate analog show poor bioavailability and selectivity for PfFPPS/GGPPS. We identified a new non-bisphosphonate compound, MMV019313, which is highly selective for PfFPPS/GGPPS and showed no activity against human FPPS or GGPPS. Inhibition of PfFPPS/GGPPS by MMV019313, but not bisphosphonates, was disrupted in an S228T variant, demonstrating that MMV019313 and bisphosphonates have distinct modes of inhibition. Molecular docking indicated that MMV019313 did not bind previously characterized substrate sites in PfFPPS/GGPPS. Our finding uncovers a new, selective small-molecule binding site in this important antimalarial drug target with superior druggability compared with the known inhibitor site and sets the stage for the development of Plasmodium-specific FPPS/GGPPS inhibitors.
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Affiliation(s)
- Jolyn E Gisselberg
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Zachary Herrera
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Lindsey M Orchard
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA; Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Ellen Yeh
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA; Department of Pathology, Stanford Medical School, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford Medical School, Stanford University, Stanford, CA 94305, USA.
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15
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Afanador GA, Guerra AJ, Swift RP, Rodriguez RE, Bartee D, Matthews KA, Schön A, Freire E, Freel Meyers CL, Prigge ST. A novel lipoate attachment enzyme is shared by Plasmodium and Chlamydia species. Mol Microbiol 2017; 106:439-451. [PMID: 28836704 DOI: 10.1111/mmi.13776] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2017] [Indexed: 12/22/2022]
Abstract
Lipoate is an essential cofactor for enzymes that are important for central metabolism and other processes. In malaria parasites, scavenged lipoate from the human host is required for survival. The Plasmodium falciparum mitochondrion contains two enzymes (PfLipL1 and PfLipL2) that are responsible for activating mitochondrial proteins through the covalent attachment of lipoate (lipoylation). Lipoylation occurs via a novel redox-gated mechanism that remains poorly understood. We show that PfLipL1 functions as a redox switch that determines which downstream proteins will be activated. Based on the lipoate redox state, PfLipL1 either functions as a canonical lipoate ligase or as a lipoate activating enzyme which works in conjunction with PfLipL2. We demonstrate that PfLipL2 is a lipoyltransferase and is a member of a novel clade of lipoate attachment enzymes. We show that a LipL2 enzyme from Chlamydia trachomatis has similar activity, demonstrating conservation between intracellular pathogens from different phylogenetic kingdoms and supporting the hypothesis that an early ancestor of malaria parasites once contained a chlamydial endosymbiont. Redox-dependent lipoylation may regulate processes such as central metabolism and oxidative defense pathways.
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Affiliation(s)
- Gustavo A Afanador
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Alfredo J Guerra
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Ryan E Rodriguez
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - David Bartee
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Krista A Matthews
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Arne Schön
- Department of Biology, The Johns Hopkins University, Baltimore, MD, USA
| | - Ernesto Freire
- Department of Biology, The Johns Hopkins University, Baltimore, MD, USA
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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16
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Guerra AJ, Afanador GA, Prigge ST. Crystal structure of lipoate-bound lipoate ligase 1, LipL1, from Plasmodium falciparum. Proteins 2017; 85:1777-1783. [PMID: 28543853 DOI: 10.1002/prot.25324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/04/2017] [Accepted: 05/17/2017] [Indexed: 11/08/2022]
Abstract
Plasmodium falciparum lipoate protein ligase 1 (PfLipL1) is an ATP-dependent ligase that belongs to the biotin/lipoate A/B protein ligase family (PFAM PF03099). PfLipL1 is the only known canonical lipoate ligase in Pf and functions as a redox switch between two lipoylation routes in the parasite mitochondrion. Here, we report the crystal structure of a deletion construct of PfLipL1 (PfLipL1Δ243-279 ) bound to lipoate, and validate the lipoylation activity of this construct in both an in vitro lipoylation assay and a cell-based lipoylation assay. This characterization represents the first step in understanding the redox dependence of the lipoylation mechanism in malaria parasites. Proteins 2017; 85:1777-1783. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Alfredo J Guerra
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Gustavo A Afanador
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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17
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Abstract
The target of rapamycin complex 1 (TORC1) pathway is a highly conserved signaling pathway across eukaryotes that integrates nutrient and stress signals to regulate the cellular growth rate and the transition into and maintenance of dormancy. The majority of the pathway's components, including the central TOR kinase, have been lost in the apicomplexan lineage, and it is unknown how these organisms detect and respond to nutrient starvation in its absence. Plasmodium falciparum encodes a putative ortholog of the RNA polymerase (Pol) III repressor Maf1, which has been demonstrated to modulate Pol III transcription in a TOR-dependent manner in a number of organisms. Here, we investigate the role of P. falciparum Maf1 (PfMaf1) in regulating RNA Pol III expression under conditions of nutrient starvation and other stresses. Using a transposon insertion mutant with an altered Maf1 expression profile, we demonstrated that proper Maf1 expression is necessary for survival of the dormancy-like state induced by prolonged amino acid starvation and is needed for full recovery from other stresses that slow or stall the parasite cell cycle. This Maf1 mutant is defective in the downregulation of pre-tRNA synthesis under nutrient-limiting conditions, indicating that the function of Maf1 as a stress-responsive regulator of structural RNA transcription is conserved in P. falciparum Recent work has demonstrated that parasites carrying artemisinin-resistant K13 alleles display an enhanced ability to recover from drug-induced growth retardation. We show that one such artemisinin-resistant line displays greater regulation of pre-tRNA expression and higher survival upon prolonged amino acid starvation, suggesting that overlapping, PfMaf1-associated pathways may regulate growth recovery from both artemisinin treatment and amino acid starvation.IMPORTANCE Eukaryote organisms sense changes in their environment and integrate this information through signaling pathways to activate response programs to ensure survival. The TOR pathway is a well-studied signaling pathway found throughout eukaryotes that is known to integrate a variety of signals to regulate organismal growth in response to starvation and other stresses. The human malaria parasite Plasmodium falciparum appears to have lost the TOR pathway over the course of evolution, and it is unclear how the parasite modulates its growth in response to starvation and drug treatment. Here, we show that Maf1, a protein regulated by TOR in other eukaryotes, plays an important role in maintaining the parasite's viability in the face of starvation and other forms of stress. This suggests that PfMaf1 is a component of a yet-to-be-described nutrient and stress response pathway.
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18
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Gisselberg JE, Zhang L, Elias JE, Yeh E. The Prenylated Proteome of Plasmodium falciparum Reveals Pathogen-specific Prenylation Activity and Drug Mechanism-of-action. Mol Cell Proteomics 2016; 16:S54-S64. [PMID: 28040698 DOI: 10.1074/mcp.m116.064550] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/01/2016] [Indexed: 11/06/2022] Open
Abstract
Plasmodium parasites contain several unique membrane compartments in which prenylated proteins may play important roles in pathogenesis. Protein prenylation has also been proposed as an antimalarial drug target because farnesyltransferase inhibitors cause potent growth inhibition of blood-stage Plasmodium However, the specific prenylated proteins that mediate antimalarial activity have yet to be identified. Given the potential for new parasite biology and elucidating drug mechanism-of-action, we performed a large-scale identification of the prenylated proteome in blood-stage P. falciparum parasites using an alkyne-labeled prenyl analog to specifically enrich parasite prenylated proteins. Twenty high-confidence candidates were identified, including several examples of pathogen-specific prenylation activity. One unique parasite prenylated protein was FYVE-containing coiled-coil protein (FCP), which is only conserved in Plasmodium and related Apicomplexan parasites and localizes to the parasite food vacuole. Targeting of FCP to this parasite-specific compartment was dependent on prenylation of its CaaX motif, as mutation of the prenylation site caused cytosolic mislocalization. We also showed that PfRab5b, which lacks C-terminal cysteines that are the only known site of Rab GTPase modification, is prenylated. Finally, we show that the THQ class of farnesyltransferase inhibitors abolishes FCP prenylation and causes its mislocalization, providing the first demonstration of a specific prenylated protein disrupted by antimalarial farnesyl transferase inhibitors. Altogether, these findings identify prenylated proteins that reveal unique parasite biology and are useful for evaluating prenyltransferase inhibitors for antimalarial drug development.
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Affiliation(s)
| | - Lichao Zhang
- ‖Chemical and Systems Biology, Stanford Medical School, Stanford University, Stanford, California 94025
| | - Joshua E Elias
- ‖Chemical and Systems Biology, Stanford Medical School, Stanford University, Stanford, California 94025
| | - Ellen Yeh
- From the ‡Department of Biochemistry, .,§Pathology.,¶Microbiology and Immunology, and
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19
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Nacer A, Claes A, Roberts A, Scheidig-Benatar C, Sakamoto H, Ghorbal M, Lopez-Rubio JJ, Mattei D. Discovery of a novel and conserved Plasmodium falciparum exported protein that is important for adhesion of PfEMP1 at the surface of infected erythrocytes. Cell Microbiol 2015; 17:1205-16. [PMID: 25703704 PMCID: PMC4654329 DOI: 10.1111/cmi.12430] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum virulence is linked to its ability to sequester in post-capillary venules in the human host. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is the main variant surface antigen implicated in this process. Complete loss of parasite adhesion is linked to a large subtelomeric deletion on chromosome 9 in a number of laboratory strains such as D10 and T9-96. Similar to the cytoadherent reference line FCR3, D10 strain expresses PfEMP1 on the surface of parasitized erythrocytes, however without any detectable cytoadhesion. To investigate which of the deleted subtelomeric genes may be implicated in parasite adhesion, we selected 12 genes for D10 complementation studies that are predicted to code for proteins exported to the red blood cell. We identified a novel single copy gene (PF3D7_0936500) restricted to P. falciparum that restores adhesion to CD36, termed here virulence-associated protein 1 (Pfvap1). Protein knockdown and gene knockout experiments confirmed a role of PfVAP1 in the adhesion process in FCR3 parasites. PfVAP1 is co-exported with PfEMP1 into the host cell via vesicle-like structures called Maurer's clefts. This study identifies a novel highly conserved parasite molecule that contributes to parasite virulence possibly by assisting PfEMP1 to establish functional adhesion at the host cell surface.
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Affiliation(s)
- Adéla Nacer
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Aurélie Claes
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Amy Roberts
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Christine Scheidig-Benatar
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Hiroshi Sakamoto
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Mehdi Ghorbal
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Jose-Juan Lopez-Rubio
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Denise Mattei
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
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20
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Plasmodium berghei glycine cleavage system T-protein is non-essential for parasite survival in vertebrate and invertebrate hosts. Mol Biochem Parasitol 2014; 197:50-5. [PMID: 25454081 DOI: 10.1016/j.molbiopara.2014.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 11/21/2022]
Abstract
T-protein, an aminomethyltransferase, represents one of the four components of glycine cleavage system (GCS) and catalyzes the transfer of methylene group from H-protein intermediate to tetrahydrofolate (THF) forming N(5), N(10)-methylene THF (CH2-THF) with the release of ammonia. The malaria parasite genome encodes T-, H- and L-proteins, but not P-protein which is a glycine decarboxylase generating the aminomethylene group. A putative GCS has been considered to be functional in the parasite mitochondrion despite the absence of a detectable P-protein homologue. In the present study, the mitochondrial localization of T-protein in the malaria parasite was confirmed by immunofluorescence and its essentiality in the entire parasite life cycle was studied by targeting the T-protein locus in Plasmodium berghei (Pb). PbT knock out parasites did not show any growth defect in asexual, sexual and liver stages indicating that the T-protein is dispensable for parasite survival in vertebrate and invertebrate hosts. The absence of P-protein homologue and the non-essentiality of T protein suggest the possible redundancy of GCS activity in the malaria parasite. Nevertheless, the H- and L-proteins of GCS could be essential for malaria parasite because of their involvement in α-ketoacid dehydrogenase reactions.
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21
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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22
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Afanador GA, Matthews KA, Bartee D, Gisselberg JE, Walters MS, Freel Meyers CL, Prigge ST. Redox-dependent lipoylation of mitochondrial proteins in Plasmodium falciparum. Mol Microbiol 2014; 94:156-71. [PMID: 25116855 PMCID: PMC4177315 DOI: 10.1111/mmi.12753] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2014] [Indexed: 11/26/2022]
Abstract
Lipoate scavenging from the human host is essential for malaria parasite survival. Scavenged lipoate is covalently attached to three parasite proteins: the H-protein and the E2 subunits of branched chain amino acid dehydrogenase (BCDH) and α-ketoglutarate dehydrogenase (KDH). We show mitochondrial localization for the E2 subunits of BCDH and KDH, similar to previously localized H-protein, demonstrating that all three lipoylated proteins reside in the parasite mitochondrion. The lipoate ligase 1, LipL1, has been shown to reside in the mitochondrion and it catalyses the lipoylation of the H-protein; however, we show that LipL1 alone cannot lipoylate BCDH or KDH. A second mitochondrial protein with homology to lipoate ligases, LipL2, does not show ligase activity and is not capable of lipoylating any of the mitochondrial substrates. Instead, BCDH and KDH are lipoylated through a novel mechanism requiring both LipL1 and LipL2. This mechanism is sensitive to redox conditions where BCDH and KDH are exclusively lipoylated under strong reducing conditions in contrast to the H-protein which is preferentially lipoylated under less reducing conditions. Thus, malaria parasites contain two different routes of mitochondrial lipoylation, an arrangement that has not been described for any other organism.
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Affiliation(s)
- Gustavo A Afanador
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, USA
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Erythrocyte lysis and Xenopus laevis oocyte rupture by recombinant Plasmodium falciparum hemolysin III. EUKARYOTIC CELL 2014; 13:1337-45. [PMID: 25148832 DOI: 10.1128/ec.00088-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Malaria kills more than 1 million people per year worldwide, with severe malaria anemia accounting for the majority of the deaths. Malaria anemia is multifactorial in etiology, including infected erythrocyte destruction and decrease in erythrocyte production, as well as destruction or clearance of noninfected erythrocytes. We identified a panspecies Plasmodium hemolysin type III related to bacterial hemolysins. The identification of a hemolysin III homologue in Plasmodium suggests a potential role in host erythrocyte lysis. Here, we report the first characterization of Plasmodium falciparum hemolysin III, showing that the soluble recombinant P. falciparum hemolysin III is a pore-forming protein capable of lysing human erythrocytes in a dose-, time-, and temperature-dependent fashion. The recombinant P. falciparum hemolysin III-induced hemolysis was partially inhibited by glibenclamide, a known channel antagonist. Studies with polyethylene glycol molecules of different molecular weights indicated a pore size of approximately 3.2 nm. Heterologous expression of recombinant P. falciparum hemolysin III in Xenopus oocytes demonstrated early hypotonic lysis similar to that of the pore-forming aquaporin control. Live fluorescence microscopy localized transfected recombinant green fluorescent protein (GFP)-tagged P. falciparum hemolysin III to the essential digestive vacuole of the P. falciparum parasite. These transfected trophozoites also possessed a swollen digestive vacuole phenotype. Native Plasmodium hemolysin III in the digestive vacuole may contribute to lysis of the parasitophorous vacuole membrane derived from the host erythrocyte. After merozoite egress from infected erythrocytes, remnant P. falciparum hemolysin III released from digestive vacuoles could potentially contribute to lysis of uninfected erythrocytes to contribute to severe life-threatening anemia.
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Gisselberg JE, Dellibovi-Ragheb TA, Matthews KA, Bosch G, Prigge ST. The suf iron-sulfur cluster synthesis pathway is required for apicoplast maintenance in malaria parasites. PLoS Pathog 2013; 9:e1003655. [PMID: 24086138 PMCID: PMC3784473 DOI: 10.1371/journal.ppat.1003655] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 08/12/2013] [Indexed: 11/19/2022] Open
Abstract
The apicoplast organelle of the malaria parasite Plasmodium falciparum contains metabolic pathways critical for liver-stage and blood-stage development. During the blood stages, parasites lacking an apicoplast can grow in the presence of isopentenyl pyrophosphate (IPP), demonstrating that isoprenoids are the only metabolites produced in the apicoplast which are needed outside of the organelle. Two of the isoprenoid biosynthesis enzymes are predicted to rely on iron-sulfur (FeS) cluster cofactors, however, little is known about FeS cluster synthesis in the parasite or the roles that FeS cluster proteins play in parasite biology. We investigated two putative FeS cluster synthesis pathways (Isc and Suf) focusing on the initial step of sulfur acquisition. In other eukaryotes, these proteins can be located in multiple subcellular compartments, raising the possibility of cross-talk between the pathways or redundant functions. In P. falciparum, SufS and its partner SufE were found exclusively the apicoplast and SufS was shown to have cysteine desulfurase activity in a complementation assay. IscS and its effector Isd11 were solely mitochondrial, suggesting that the Isc pathway cannot contribute to apicoplast FeS cluster synthesis. The Suf pathway was disrupted with a dominant negative mutant resulting in parasites that were only viable when supplemented with IPP. These parasites lacked the apicoplast organelle and its organellar genome--a phenotype not observed when isoprenoid biosynthesis was specifically inhibited with fosmidomycin. Taken together, these results demonstrate that the Suf pathway is essential for parasite survival and has a fundamental role in maintaining the apicoplast organelle in addition to any role in isoprenoid biosynthesis.
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Affiliation(s)
- Jolyn E. Gisselberg
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Teegan A. Dellibovi-Ragheb
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Krista A. Matthews
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Gundula Bosch
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Sean T. Prigge
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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Falkard B, Kumar TRS, Hecht LS, Matthews KA, Henrich PP, Gulati S, Lewis RE, Manary MJ, Winzeler EA, Sinnis P, Prigge ST, Heussler V, Deschermeier C, Fidock D. A key role for lipoic acid synthesis during Plasmodium liver stage development. Cell Microbiol 2013; 15:1585-604. [PMID: 23490300 DOI: 10.1111/cmi.12137] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 03/01/2013] [Accepted: 03/07/2013] [Indexed: 12/24/2022]
Abstract
The successful navigation of malaria parasites through their life cycle, which alternates between vertebrate hosts and mosquito vectors, requires a complex interplay of metabolite synthesis and salvage pathways. Using the rodent parasite Plasmodium berghei, we have explored the synthesis and scavenging pathways for lipoic acid, a short-chain fatty acid derivative that regulates the activity of α-ketoacid dehydrogenases including pyruvate dehydrogenase. In Plasmodium, lipoic acid is either synthesized de novo in the apicoplast or is scavenged from the host into the mitochondrion. Our data show that sporozoites lacking the apicoplast lipoic acid protein ligase LipB are markedly attenuated in their infectivity for mice, and in vitro studies document a very late liver stage arrest shortly before the final phase of intra-hepaticparasite maturation. LipB-deficient asexual blood stage parasites show unimpaired rates of growth in normal in vitro or in vivo conditions. However, these parasites showed reduced growth in lipid-restricted conditions induced by treatment with the lipoic acid analogue 8-bromo-octanoate or with the lipid-reducing agent clofibrate. This finding has implications for understanding Plasmodium pathogenesis in malnourished children that bear the brunt of malarial disease. This study also highlights the potential of exploiting lipid metabolism pathways for the design of genetically attenuated sporozoite vaccines.
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Affiliation(s)
- Brie Falkard
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
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26
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Folate metabolism in human malaria parasites—75 years on. Mol Biochem Parasitol 2013; 188:63-77. [DOI: 10.1016/j.molbiopara.2013.02.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/15/2013] [Accepted: 02/19/2013] [Indexed: 12/21/2022]
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Salcedo-Sora JE, Ward SA. The folate metabolic network of Falciparum malaria. Mol Biochem Parasitol 2013; 188:51-62. [PMID: 23454873 DOI: 10.1016/j.molbiopara.2013.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 02/04/2013] [Accepted: 02/11/2013] [Indexed: 01/07/2023]
Abstract
The targeting of key enzymes in the folate pathway continues to be an effective chemotherapeutic approach that has earned antifolate drugs a valuable position in the medical pharmacopoeia. The successful therapeutic use of antifolates as antimalarials has been a catalyst for ongoing research into the biochemistry of folate and pterin biosynthesis in malaria parasites. However, our understanding of the parasites folate metabolism remains partial and patchy, especially in relation to the shikimate pathway, the folate cycle, and folate salvage. A sizeable number of potential folate targets remain to be characterised. Recent reports on the parasite specific transport of folate precursors that would normally be present in the human host awaken previous hypotheses on the salvage of folate precursors or by-products. As the parasite progresses through its life-cycle it encounters very contrasting host cell environments that present radically different metabolic milieus and biochemical challenges. It would seem probable that as the parasite encounters differing environments it would need to modify its biochemistry. This would be reflected in the folate homeostasis in Plasmodium. Recent drug screening efforts and insights into folate membrane transport substantiate the argument that folate metabolism may still offer unexplored opportunities for therapeutic attack.
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Affiliation(s)
- J Enrique Salcedo-Sora
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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A quantitative analysis of Plasmodium falciparum transfection using DNA-loaded erythrocytes. Mol Biochem Parasitol 2013; 187:117-20. [PMID: 23313825 DOI: 10.1016/j.molbiopara.2013.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/02/2013] [Accepted: 01/04/2013] [Indexed: 11/20/2022]
Abstract
Genetic modification of Plasmodium falciparum is a key molecular tool for the investigation of the biology and pathogenesis of this important human pathogen. The most effective means to introduce exogenous DNA into P. falciparum is via passive uptake following invasion into a DNA-loaded erythrocyte. Using bioluminescence as a tool to quantify transfection efficiency, parameters previously judged empirically to enhance transfection efficiency were subjected to a quantitative analysis. This report supports roles for fresh erythrocytes and growth medium supplemented with human serum in enhancing transfection efficiency. Critically, a proposed enhancement to transfection efficiency through continued feeding with DNA-loaded erythrocytes is not borne out in this study, and actually appears to be detrimental.
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Sakura T, Yahata K, Kaneko O. The upstream sequence segment of the C-terminal cysteine-rich domain is required for microneme trafficking of Plasmodium falciparum erythrocyte binding antigen 175. Parasitol Int 2012; 62:157-64. [PMID: 23268338 DOI: 10.1016/j.parint.2012.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 12/14/2012] [Accepted: 12/16/2012] [Indexed: 12/31/2022]
Abstract
Erythrocyte invasion is a critical step for survival of Plasmodium parasites, the causative agents of malaria, in their host and recognition of the host cell receptors by Plasmodium erythrocyte-binding-like (EBL) proteins plays an important role. Although EBL subcellular localization was shown to be closely linked to parasite virulence in the rodent model of malaria, the trafficking of EBL to micronemes, the secretory organelle in the invasive parasite is not fully understood. In this study, we assessed the impact of the deletion and amino acid replacement of Plasmodium falciparum EBL (EBA-175) using transgenic P. falciparum lines expressing modified EBA-175. We found that, in addition to a signal peptide and a cysteine rich region (region 6) to the cytoplasmic tail, a previously unrecognized sequence segment in region 5 was required for correct microneme trafficking of EBA-175. Replacement of Arg or Phe residues in this segment altered microneme trafficking, suggesting that the sequence itself contained critical information. Based on these findings, we propose that the sequence segment in region 5 is also required for the recognition of EBA-175 by the trafficking machinery to direct this protein to the microneme. Our results provide key information to clarify an as yet unidentified EBA-175 trafficking mechanism.
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Affiliation(s)
- Takaya Sakura
- Department of Protozoology, Institute of Tropical Medicine and Global COE Program, Nagasaki University, Sakamoto, Nagasaki, Japan
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Storm J, Müller S. Lipoic acid metabolism of Plasmodium--a suitable drug target. Curr Pharm Des 2012; 18:3480-9. [PMID: 22607141 PMCID: PMC3426790 DOI: 10.2174/138161212801327266] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/12/2012] [Indexed: 11/22/2022]
Abstract
α-Lipoic acid (6,8-thioctic acid; LA) is a vital co-factor of α-ketoacid dehydrogenase complexes and the glycine cleavage system. In recent years it was shown that biosynthesis and salvage of LA in Plasmodium are necessary for the parasites to complete their complex life cycle. LA salvage requires two lipoic acid protein ligases (LplA1 and LplA2). LplA1 is confined to the mitochondrion while LplA2 is located in both the mitochondrion and the apicoplast. LplA1 exclusively uses salvaged LA and lipoylates α-ketoglutarate dehydrogenase, branched chain α-ketoacid dehydrogenase and the H-protein of the glycine cleavage system. LplA2 cannot compensate for the loss of LplA1 function during blood stage development suggesting a specific function for LplA2 that has yet to be elucidated. LA salvage is essential for the intra-erythrocytic and liver stage development of Plasmodium and thus offers great potential for future drug or vaccine development. LA biosynthesis, comprising octanoyl-acyl carrier protein (ACP) : protein N-octanoyltransferase (LipB) and lipoate synthase (LipA), is exclusively found in the apicoplast of Plasmodium where it generates LA de novo from octanoyl-ACP, provided by the type II fatty acid biosynthesis (FAS II) pathway also present in the organelle. LA is the co-factor of the acetyltransferase subunit of the apicoplast located pyruvate dehydrogenase (PDH), which generates acetyl-CoA, feeding into FAS II. LA biosynthesis is not vital for intra-erythrocytic development of Plasmodium, but the deletion of several genes encoding components of FAS II or PDH was detrimental for liver stage development of the parasites indirectly suggesting that the same applies to LA biosynthesis. These data provide strong evidence that LA salvage and biosynthesis are vital for different stages of Plasmodium development and offer potential for drug and vaccine design against malaria.
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Affiliation(s)
- Janet Storm
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
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Comparison of the absolute and relative efficiencies of electroporation-based transfection protocols for Plasmodium falciparum. Malar J 2012; 11:210. [PMID: 22720754 PMCID: PMC3407700 DOI: 10.1186/1475-2875-11-210] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/21/2012] [Indexed: 11/18/2022] Open
Abstract
Background Several electroporation protocols exist to transfect exogenous DNA into Plasmodium falciparum. To date, however, only a subjective analysis of their relative efficiencies has been reported. Methods A time-course of luciferase reporter expression is used to provide an objective quantitative analysis of the absolute efficiency of three electroporation techniques; direct electroporation of ring stage infected erythrocytes, preloading of erythrocytes and a novel “double-tap” protocol that combines both approaches. Results Preloading of erythrocytes shows a mean efficiency of 9.59x10-6, some 5–180 fold more efficient than matched experiments utilizing the “double-tap” and direct electroporation of ring stage infected erythrocytes alone, respectively. Conclusion Evidence presented here provides the first quantitative assessment of both the absolute and relative efficiencies of a key molecular tool used to study the biology and pathogenesis of this important human pathogen.
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Gallagher JR, Matthews KA, Prigge ST. Plasmodium falciparum apicoplast transit peptides are unstructured in vitro and during apicoplast import. Traffic 2011; 12:1124-38. [PMID: 21668595 DOI: 10.1111/j.1600-0854.2011.01232.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Trafficking of soluble proteins to the apicoplast in Plasmodium falciparum is determined by an N-terminal transit peptide (TP) which is necessary and sufficient for apicoplast import. Apicoplast precursor proteins are synthesized at the rough endoplasmic reticulum, but are then specifically sorted from other proteins in the secretory pathway. The mechanism of TP recognition is presently unknown. Apicoplast TPs do not contain a conserved sequence motif; therefore, we asked whether they contain an essential structural motif. Using nuclear magnetic resonance to study a model TP from acyl carrier protein, we found a short, low-occupancy helix, but the TP was otherwise disordered. Using an in vivo localization assay, we blocked TP secondary structure by proline mutagenesis, but found robust apicoplast localization. Alternatively, we increased the helical content of the TP through mutation while maintaining established TP characteristics. Apicoplast import was disrupted in a helical mutant TP, but import was then restored by the further addition of a single proline. We conclude that structure in the TP interferes with apicoplast import, and therefore TPs are functionally disordered. These results provide an explanation for the amino acid bias observed in apicoplast TPs.
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Affiliation(s)
- John R Gallagher
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Room E5132, 615 North Wolfe Street, Baltimore, MD 21205, USA
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Wong EH, Hasenkamp S, Horrocks P. Analysis of the molecular mechanisms governing the stage-specific expression of a prototypical housekeeping gene during intraerythrocytic development of P. falciparum. J Mol Biol 2011; 408:205-21. [PMID: 21354176 PMCID: PMC3081073 DOI: 10.1016/j.jmb.2011.02.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 02/10/2011] [Accepted: 02/17/2011] [Indexed: 01/22/2023]
Abstract
Gene expression during the intraerythrocytic development cycle of the human malarial parasite Plasmodium falciparum is subject to tight temporal control, resulting in a cascade of gene expression to meet the physiological demands of growth, replication, and reinvasion. The roles of the different molecular mechanisms that drive this temporal program of gene expression are poorly understood. Here we report the use of the bxb1 integrase system to reconstitute all aspects of the absolute and temporal control of the prototypical housekeeping gene encoding the proliferating cell nuclear antigen (Pfpcna) around an integrated luciferase reporter cassette. A quantitative analysis of the effect of the serial deletion of 5′ and 3′ genetic elements and sublethal doses of histone deacetylase inhibitors demonstrates that while the absolute control of gene expression could be perturbed, no effect on the temporal control of gene expression was observed. These data provide support for a novel model for the temporal control of potentially hundreds of genes during the intraerythrocytic development of this important human pathogen.
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Affiliation(s)
- Eleanor H. Wong
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Sandra Hasenkamp
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Paul Horrocks
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK
- Corresponding author. Institute for Science and Technology in Medicine, Keele University, Huxley Building, Staffordshire ST5 5BG, UK.
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Read M, Müller IB, Mitchell SL, Sims PFG, Hyde JE. Dynamic subcellular localization of isoforms of the folate pathway enzyme serine hydroxymethyltransferase (SHMT) through the erythrocytic cycle of Plasmodium falciparum. Malar J 2010; 9:351. [PMID: 21129192 PMCID: PMC3014972 DOI: 10.1186/1475-2875-9-351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 12/03/2010] [Indexed: 11/10/2022] Open
Abstract
Background The folate pathway enzyme serine hydroxymethyltransferase (SHMT) converts serine to glycine and 5,10-methylenetetrahydrofolate and is essential for the acquisition of one-carbon units for subsequent transfer reactions. 5,10-methylenetetrahydrofolate is used by thymidylate synthase to convert dUMP to dTMP for DNA synthesis. In Plasmodium falciparum an enzymatically functional SHMT (PfSHMTc) and a related, apparently inactive isoform (PfSHMTm) are found, encoded by different genes. Here, patterns of localization of the two isoforms during the parasite erythrocytic cycle are investigated. Methods Polyclonal antibodies were raised to PfSHMTc and PfSHMTm, and, together with specific markers for the mitochondrion and apicoplast, were employed in quantitative confocal fluorescence microscopy of blood-stage parasites. Results As well as the expected cytoplasmic occupancy of PfSHMTc during all stages, localization into the mitochondrion and apicoplast occurred in a stage-specific manner. Although early trophozoites lacked visible organellar PfSHMTc, a significant percentage of parasites showed such fluorescence during the mid-to-late trophozoite and schizont stages. In the case of the mitochondrion, the majority of parasites in these stages at any given time showed no marked PfSHMTc fluorescence, suggesting that its occupancy of this organelle is of limited duration. PfSHMTm showed a distinctly more pronounced mitochondrial location through most of the erythrocytic cycle and GFP-tagging of its N-terminal region confirmed the predicted presence of a mitochondrial signal sequence. Within the apicoplast, a majority of mitotic schizonts showed a marked concentration of PfSHMTc, whose localization in this organelle was less restricted than for the mitochondrion and persisted from the late trophozoite to the post-mitotic stages. PfSHMTm showed a broadly similar distribution across the cycle, but with a distinctive punctate accumulation towards the ends of elongating apicoplasts. In very late post-mitotic schizonts, both PfSHMTc and PfSHMTm were concentrated in the central region of the parasite that becomes the residual body on erythrocyte lysis and merozoite release. Conclusions Both PfSHMTc and PfSHMTm show dynamic, stage-dependent localization among the different compartments of the parasite and sequence analysis suggests they may also reversibly associate with each other, a factor that may be critical to folate cofactor function, given the apparent lack of enzymic activity of PfSHMTm.
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Affiliation(s)
- Martin Read
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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