1
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MacLean AE, Shikha S, Ferreira Silva M, Gramelspacher MJ, Nilsen A, Liebman KM, Pou S, Winter RW, Meir A, Riscoe MK, Doggett JS, Sheiner L, Mühleip A. Structure, assembly and inhibition of the Toxoplasma gondii respiratory chain supercomplex. Nat Struct Mol Biol 2025:10.1038/s41594-025-01531-7. [PMID: 40389671 DOI: 10.1038/s41594-025-01531-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 03/12/2025] [Indexed: 05/21/2025]
Abstract
The apicomplexan mitochondrial electron transport chain is essential for parasite survival and displays a divergent subunit composition. Here we report cryo-electron microscopy structures of an apicomplexan III2-IV supercomplex and of the drug target complex III2. The supercomplex structure reveals how clade-specific subunits form an apicomplexan-conserved III2-IV interface with a unique, kinked architecture, suggesting that supercomplexes evolved independently in different eukaryotic lineages. A knockout resulting in supercomplex disassembly challenges the proposed role of III2-IV in electron transfer efficiency as suggested for mammals. Nevertheless, knockout analysis indicates that III2-IV is critical for parasite fitness. The complexes from the model parasite Toxoplasma gondii were inhibited with the antimalarial atovaquone, revealing interactions underpinning species specificity. They were also inhibited with endochin-like quinolone (ELQ)-300, an inhibitor in late-stage preclinical development. Notably, in the apicomplexan binding site, ELQ-300 is flipped compared with related compounds in the mammalian enzyme. On the basis of the binding modes and parasite-specific interactions discovered, we designed more potent ELQs with subnanomolar activity against T. gondii. Our findings reveal critical evolutionary differences in the role of supercomplexes in mitochondrial biology and provide insight into cytochrome b inhibition, informing future drug discovery.
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Affiliation(s)
- Andrew E MacLean
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
- Glasgow Centre for Parasitology, University of Glasgow, Glasgow, UK
| | - Shikha Shikha
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
- Glasgow Centre for Parasitology, University of Glasgow, Glasgow, UK
| | - Mariana Ferreira Silva
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
- Glasgow Centre for Parasitology, University of Glasgow, Glasgow, UK
| | | | - Aaron Nilsen
- VA Portland Health Care System, Portland, OR, USA
- Medicinal Chemistry Core, Oregon Health and Science University, Portland, OR, USA
| | | | - Sovitj Pou
- VA Portland Health Care System, Portland, OR, USA
| | | | - Amit Meir
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
- Centre for Virus Research, University of Glasgow, Glasgow, UK
| | - Michael K Riscoe
- VA Portland Health Care System, Portland, OR, USA
- Department of Microbiology and Molecular Immunology, Oregon Health and Science University, Portland, OR, USA
| | - J Stone Doggett
- VA Portland Health Care System, Portland, OR, USA
- School of Medicine Division of Infectious Diseases, Oregon Health and Science University, Portland, OR, USA
| | - Lilach Sheiner
- School of Infection and Immunity, University of Glasgow, Glasgow, UK.
- Glasgow Centre for Parasitology, University of Glasgow, Glasgow, UK.
| | - Alexander Mühleip
- School of Infection and Immunity, University of Glasgow, Glasgow, UK.
- Glasgow Centre for Parasitology, University of Glasgow, Glasgow, UK.
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, Helsinki, Finland.
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2
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García-Guerrero AE, Marvin RG, Blackwell AM, Sigala PA. Biogenesis of Cytochromes c and c1 in the Electron Transport Chain of Malaria Parasites. ACS Infect Dis 2025; 11:813-826. [PMID: 39481007 PMCID: PMC11991887 DOI: 10.1021/acsinfecdis.4c00450] [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] [Indexed: 11/02/2024]
Abstract
Plasmodium malaria parasites retain an essential mitochondrional electron transport chain (ETC) that is critical for growth within humans and mosquitoes and is a key antimalarial drug target. ETC function requires cytochromes c and c1, which are unusual among heme proteins due to their covalent binding to heme via conserved CXXCH sequence motifs. Heme attachment to these proteins in most eukaryotes requires the mitochondrial enzyme holocytochrome c synthase (HCCS) that binds heme and the apo cytochrome to facilitate the biogenesis of the mature cytochrome c or c1. Although humans encode a single bifunctional HCCS that attaches heme to both proteins, Plasmodium parasites are like yeast and encode two separate HCCS homologues thought to be specific for heme attachment to cyt c (HCCS) or cyt c1 (HCC1S). To test the function and specificity of Plasmodium falciparum HCCS and HCC1S, we used CRISPR/Cas9 to tag both genes for conditional expression. HCC1S knockdown selectively impaired cyt c1 biogenesis and caused lethal ETC dysfunction that was not reversed by the overexpression of HCCS. Knockdown of HCCS caused a more modest growth defect but strongly sensitized parasites to mitochondrial depolarization by proguanil, revealing key defects in ETC function. These results and prior heterologous studies in Escherichia coli of cyt c hemylation by P. falciparum HCCS and HCC1S strongly suggest that both homologues are essential for mitochondrial ETC function and have distinct specificities for the biogenesis of cyt c and c1, respectively, in parasites. This study lays a foundation to develop novel strategies to selectively block ETC function in malaria parasites.
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Affiliation(s)
- Aldo E. García-Guerrero
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Rebecca G. Marvin
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Amanda Mixon Blackwell
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
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3
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Chen M, Koszti SG, Bonavoglia A, Maco B, von Rohr O, Peng HJ, Soldati-Favre D, Kloehn J. Dissecting apicoplast functions through continuous cultivation of Toxoplasma gondii devoid of the organelle. Nat Commun 2025; 16:2095. [PMID: 40025025 PMCID: PMC11873192 DOI: 10.1038/s41467-025-57302-x] [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: 06/13/2024] [Accepted: 02/18/2025] [Indexed: 03/04/2025] Open
Abstract
The apicoplast, a relic plastid organelle derived from secondary endosymbiosis, is crucial for many medically relevant Apicomplexa. While it no longer performs photosynthesis, the organelle retains several essential metabolic pathways. In this study, we examine the four primary metabolic pathways in the Toxoplasma gondii apicoplast, along with an accessory pathway, and identify conditions that can bypass these. Contrary to the prevailing view that the apicoplast is indispensable for T. gondii, we demonstrate that bypassing all pathways renders the apicoplast non-essential. We further show that T. gondii lacking an apicoplast (T. gondii-Apico) can be maintained indefinitely in culture, establishing a unique model to study the functions of this organelle. Through comprehensive metabolomic, transcriptomic, and proteomic analyses of T. gondii-Apico we uncover significant adaptation mechanisms following loss of the organelle and identify numerous putative apicoplast proteins revealed by their decreased abundance in T. gondii-Apico. Moreover, T. gondii-Apico parasites exhibit reduced sensitivity to apicoplast targeting compounds, providing a valuable tool for discovering new drugs acting on the organelle. The capability to culture T. gondii without its plastid offers new avenues for exploring apicoplast biology and developing novel therapeutic strategies against apicomplexan parasites.
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Affiliation(s)
- Min Chen
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland
| | - Szilamér Gyula Koszti
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland
| | - Alessandro Bonavoglia
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland
| | - Olivier von Rohr
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland
| | - Hong-Juan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health; Key Laboratory of Infectious Diseases Research in South China (Ministry of Education), Southern Medical University, Guangzhou City, Guangdong Province, China.
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland.
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, Geneva, Switzerland.
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4
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Bai R, Wang H, Yang T, Yan Y, Zhu S, Lv C, Pei Y, Guo J, Li J, Cui X, Lv X, Zheng M. Mechanisms of Mitochondria-Mediated Apoptosis During Eimeria tenella Infection. Animals (Basel) 2025; 15:577. [PMID: 40003058 PMCID: PMC11852116 DOI: 10.3390/ani15040577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2025] [Revised: 02/10/2025] [Accepted: 02/14/2025] [Indexed: 02/27/2025] Open
Abstract
Coccidiosis in chickens is a parasitic disease caused by Eimeria species, resulting in significant economic losses to the poultry industry. Among these species, Eimeria tenella is considered the most virulent pathogen, with its infection strongly associated with the apoptotic response of host cells. Eimeria tenella modulates host cell apoptosis in a stage-specific manner, suppressing apoptosis in the early phase to promote its intracellular development and triggering apoptosis in later stages to facilitate parasite egress and disease progression. This study established an in vitro infection model using 60 fifteen-day-old chick embryo cecal epithelial cells and infecting the cells with Eimeria tenella sporozoites at a 1:1 ratio of host cells to sporozoites. The aim was to examine the relationship between parasitic infection and the apoptotic response of host cells in the chick embryo cecal epithelial cells infected with E. tenella. The roles of the mitochondrial permeability transition pore (MPTP) and cytochrome c in intrinsic apoptosis were examined through the application of cyclosporine A (CsA), N, N, N', N'-tetramethyl-1,4-phenylenediamine (TMPD), and ascorbate (Asc). TUNEL staining, ELISA, and flow cytometry were performed to evaluate apoptotic rates. CsA, TMPD, and Asc significantly (p < 0.01) decreased cytochrome c release, caspase-9 activation, and apoptotic rates from 24 to 120 h post-E. tenella infection. These findings highlight the significance of cytochrome c-mediated, mitochondria-dependent apoptotic pathways in parasitized chick embryo cecal epithelial cells.
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Affiliation(s)
- Rui Bai
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
- Shanxi Key Laboratory for Modernization of TCVM, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Hui Wang
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
- Shanxi Key Laboratory for Modernization of TCVM, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Tiantian Yang
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Yuqi Yan
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Shuying Zhu
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Chenyang Lv
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Yang Pei
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Jiale Guo
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Jianhui Li
- College of Animal Science, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Xiaozhen Cui
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Xiaoling Lv
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
| | - Mingxue Zheng
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Jinzhong 030801, China
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5
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Renaud EA, Maupin AJM, Besteiro S. Iron‑sulfur cluster biogenesis and function in Apicomplexa parasites. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2025; 1872:119876. [PMID: 39547273 DOI: 10.1016/j.bbamcr.2024.119876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2024] [Revised: 11/05/2024] [Accepted: 11/06/2024] [Indexed: 11/17/2024]
Abstract
Iron‑sulfur cluster are ubiquitous and ancient protein cofactors that support a wide array of essential cellular functions. In eukaryotes, their assembly requires specific and dedicated machineries in each subcellular compartment. Apicomplexans are parasitic protists that are collectively responsible for a significant burden on the health of humans and other animals, and most of them harbor two organelles of endosymbiotic origin: a mitochondrion, and a plastid of high metabolic importance called the apicoplast. Consequently, apicomplexan parasites have distinct iron‑sulfur cluster assembly machineries located to their endosymbiotic organelles, as well as a cytosolic pathway. Recent findings have not only shown the importance of iron‑sulfur cluster assembly for the fitness of these parasites, but also highlighted parasite-specific features that may be promising for the development of targeted anti-parasitic strategies.
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6
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García-Guerrero AE, Marvin RG, Blackwell AM, Sigala PA. Biogenesis of cytochromes c and c 1 in the electron transport chain of malaria parasites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.575742. [PMID: 38352463 PMCID: PMC10862854 DOI: 10.1101/2024.02.01.575742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Plasmodium malaria parasites retain an essential mitochondrional electron transport chain (ETC) that is critical for growth within humans and mosquitoes and a key antimalarial drug target. ETC function requires cytochromes c and c 1 that are unusual among heme proteins due to their covalent binding to heme via conserved CXXCH sequence motifs. Heme attachment to these proteins in most eukaryotes requires the mitochondrial enzyme holocytochrome c synthase (HCCS) that binds heme and the apo cytochrome to facilitate biogenesis of the mature cytochrome c or c 1. Although humans encode a single bifunctional HCCS that attaches heme to both proteins, Plasmodium parasites are like yeast and encode two separate HCCS homologs thought to be specific for heme attachment to cyt c (HCCS) or cyt c 1 (HCC1S). To test the function and specificity of P. falciparum HCCS and HCC1S, we used CRISPR/Cas9 to tag both genes for conditional expression. HCC1S knockdown selectively impaired cyt c 1 biogenesis and caused lethal ETC dysfunction that was not reversed by over-expression of HCCS. Knockdown of HCCS caused a more modest growth defect but strongly sensitized parasites to mitochondrial depolarization by proguanil, revealing key defects in ETC function. These results and prior heterologous studies in E. coli of cyt c hemylation by P. falciparum HCCS and HCC1S strongly suggest that both homologs are essential for mitochondrial ETC function and have distinct specificities for biogenesis of cyt c and c 1, respectively, in parasites. This study lays a foundation to develop novel strategies to selectively block ETC function in malaria parasites.
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Affiliation(s)
- Aldo E. García-Guerrero
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Rebecca G. Marvin
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Amanda Mixon Blackwell
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
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7
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Maclean AE, Sloan MA, Renaud EA, Argyle BE, Lewis WH, Ovciarikova J, Demolombe V, Waller RF, Besteiro S, Sheiner L. The Toxoplasma gondii mitochondrial transporter ABCB7L is essential for the biogenesis of cytosolic and nuclear iron-sulfur cluster proteins and cytosolic translation. mBio 2024; 15:e0087224. [PMID: 39207139 PMCID: PMC11481526 DOI: 10.1128/mbio.00872-24] [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: 03/21/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024] Open
Abstract
Iron-sulfur (Fe-S) clusters are ubiquitous inorganic cofactors required for numerous essential cellular pathways. Since they cannot be scavenged from the environment, Fe-S clusters are synthesized de novo in cellular compartments such as the apicoplast, mitochondrion, and cytosol. The cytosolic Fe-S cluster biosynthesis pathway relies on the transport of an intermediate from the mitochondrial pathway. An ATP-binding cassette (ABC) transporter called ABCB7 is responsible for this role in numerous commonly studied organisms, but its role in the medically important apicomplexan parasites has not yet been studied. Here we identify and characterize a Toxoplasma gondii ABCB7 homolog, which we name ABCB7-like (ABCB7L). Genetic depletion shows that it is essential for parasite growth and that its disruption triggers partial stage conversion. Characterization of the knock-down line highlights a defect in the biogenesis of cytosolic and nuclear Fe-S proteins leading to defects in protein translation and other pathways including DNA and RNA replication and metabolism. Our work provides support for a broad conservation of the connection between mitochondrial and cytosolic pathways in Fe-S cluster biosynthesis and reveals its importance for parasite survival. IMPORTANCE Iron-sulfur (Fe-S) clusters are inorganic cofactors of proteins that play key roles in numerous essential biological processes, for example, respiration and DNA replication. Cells possess dedicated biosynthetic pathways to assemble Fe-S clusters, including a pathway in the mitochondrion and cytosol. A single transporter, called ABCB7, connects these two pathways, allowing an essential intermediate generated by the mitochondrial pathway to be used in the cytosolic pathway. Cytosolic and nuclear Fe-S proteins are dependent on the mitochondrial pathway, mediated by ABCB7, in numerous organisms studied to date. Here, we study the role of a homolog of ABCB7, which we name ABCB7-like (ABCB7L), in the ubiquitous unicellular apicomplexan parasite Toxoplasma gondii. We generated a depletion mutant of Toxoplasma ABCB7L and showed its importance for parasite fitness. Using comparative quantitative proteomic analysis and experimental validation of the mutants, we show that ABCB7L is required for cytosolic and nuclear, but not mitochondrial, Fe-S protein biogenesis. Our study supports the conservation of a protein homologous to ABCB7 and which has a similar function in apicomplexan parasites and provides insight into an understudied aspect of parasite metabolism.
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Affiliation(s)
- Andrew E. Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Megan A. Sloan
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Eléa A. Renaud
- LPHI, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Blythe E. Argyle
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
| | - William H. Lewis
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jana Ovciarikova
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Vincent Demolombe
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
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8
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Zwahlen SM, Hayward JA, Maguire CS, Qin AR, van Dooren GG. A myzozoan-specific protein is an essential membrane-anchoring component of the succinate dehydrogenase complex in Toxoplasma parasites. Open Biol 2024; 14:230463. [PMID: 38835243 DOI: 10.1098/rsob.230463] [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: 12/22/2023] [Accepted: 01/15/2024] [Indexed: 06/06/2024] Open
Abstract
Succinate dehydrogenase (SDH) is a protein complex that functions in the tricarboxylic acid cycle and the electron transport chain of mitochondria. In most eukaryotes, SDH is highly conserved and comprises the following four subunits: SdhA and SdhB form the catalytic core of the complex, while SdhC and SdhD anchor the complex in the membrane. Toxoplasma gondii is an apicomplexan parasite that infects one-third of humans worldwide. The genome of T. gondii encodes homologues of the catalytic subunits SdhA and SdhB, although the physiological role of the SDH complex in the parasite and the identity of the membrane-anchoring subunits are poorly understood. Here, we show that the SDH complex contributes to optimal proliferation and O2 consumption in the disease-causing tachyzoite stage of the T. gondii life cycle. We characterize a small membrane-bound subunit of the SDH complex called mitochondrial protein ookinete developmental defect (MPODD), which is conserved among myzozoans, a phylogenetic grouping that incorporates apicomplexan parasites and their closest free-living relatives. We demonstrate that TgMPODD is essential for SDH activity and plays a key role in attaching the TgSdhA and TgSdhB proteins to the membrane anchor of the complex. Our findings highlight a unique and important feature of mitochondrial energy metabolism in apicomplexan parasites and their relatives.
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Affiliation(s)
- Soraya M Zwahlen
- Research School of Biology, Australian National University , Canberra, Australian Capital Territory, Australia
| | - Jenni A Hayward
- Research School of Biology, Australian National University , Canberra, Australian Capital Territory, Australia
| | - Capella S Maguire
- Research School of Biology, Australian National University , Canberra, Australian Capital Territory, Australia
| | - Alex R Qin
- Research School of Biology, Australian National University , Canberra, Australian Capital Territory, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University , Canberra, Australian Capital Territory, Australia
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9
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Ovciarikova J, Shikha S, Lacombe A, Courjol F, McCrone R, Hussain W, Maclean A, Lemgruber L, Martins-Duarte ES, Gissot M, Sheiner L. Two ancient membrane pores mediate mitochondrial-nucleus membrane contact sites. J Cell Biol 2024; 223:e202304075. [PMID: 38456969 PMCID: PMC10923651 DOI: 10.1083/jcb.202304075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/28/2023] [Accepted: 01/29/2024] [Indexed: 03/09/2024] Open
Abstract
Coordination between nucleus and mitochondria is essential for cell survival, and thus numerous communication routes have been established between these two organelles over eukaryotic cell evolution. One route for organelle communication is via membrane contact sites, functional appositions formed by molecular tethers. We describe a novel nuclear-mitochondrial membrane contact site in the protozoan Toxoplasma gondii. We have identified specific contacts occurring at the nuclear pore and demonstrated an interaction between components of the nuclear pore and the mitochondrial protein translocon, highlighting them as molecular tethers. Genetic disruption of the nuclear pore or the TOM translocon components, TgNup503 or TgTom40, respectively, result in contact site reduction, supporting their potential involvement in this tether. TgNup503 depletion further leads to specific mitochondrial morphology and functional defects, supporting a role for nuclear-mitochondrial contacts in mediating their communication. The discovery of a contact formed through interaction between two ancient mitochondrial and nuclear complexes sets the ground for better understanding of mitochondrial-nuclear crosstalk in eukaryotes.
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Affiliation(s)
- Jana Ovciarikova
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Shikha Shikha
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Alice Lacombe
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Flavie Courjol
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, University of Lille, Lille, France
| | - Rosalind McCrone
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Wasim Hussain
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Andrew Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Leandro Lemgruber
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Erica S. Martins-Duarte
- Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mathieu Gissot
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, University of Lille, Lille, France
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
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10
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Pietsch E, Ramaprasad A, Bielfeld S, Wohlfarter Y, Maco B, Niedermüller K, Wilcke L, Kloehn J, Keller MA, Soldati-Favre D, Blackman MJ, Gilberger TW, Burda PC. A patatin-like phospholipase is important for mitochondrial function in malaria parasites. mBio 2023; 14:e0171823. [PMID: 37882543 PMCID: PMC10746288 DOI: 10.1128/mbio.01718-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE For their proliferation within red blood cells, malaria parasites depend on a functional electron transport chain (ETC) within their mitochondrion, which is the target of several antimalarial drugs. Here, we have used gene disruption to identify a patatin-like phospholipase, PfPNPLA2, as important for parasite replication and mitochondrial function in Plasmodium falciparum. Parasites lacking PfPNPLA2 show defects in their ETC and become hypersensitive to mitochondrion-targeting drugs. Furthermore, PfPNPLA2-deficient parasites show differences in the composition of their cardiolipins, a unique class of phospholipids with key roles in mitochondrial functions. Finally, we demonstrate that parasites devoid of PfPNPLA2 have a defect in gametocyte maturation, underlining the importance of a functional ETC for parasite transmission to the mosquito vector.
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Affiliation(s)
- Emma Pietsch
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Abhinay Ramaprasad
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Sabrina Bielfeld
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Yvonne Wohlfarter
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Korbinian Niedermüller
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Louisa Wilcke
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Markus A. Keller
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Michael J. Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Tim-Wolf Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Paul-Christian Burda
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
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11
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Rodriguez JB, Szajnman SH. An updated review of chemical compounds with anti-Toxoplasma gondii activity. Eur J Med Chem 2023; 262:115885. [PMID: 37871407 DOI: 10.1016/j.ejmech.2023.115885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/30/2023] [Accepted: 10/15/2023] [Indexed: 10/25/2023]
Abstract
The opportunistic apicomplexan parasite Toxoplasma gondii is the etiologic agent for toxoplasmosis, which can infect a widespread range of hosts, particularly humans and warm-blooded animals. The present chemotherapy to treat or prevent toxoplasmosis is deficient and is based on diverse drugs such as atovaquone, trimethoprim, spiramycine, which are effective in acute toxoplasmosis. Therefore, a safe chemotherapy is required for toxoplasmosis considering that its responsible agent, T. gondii, provokes severe illness and death in pregnant women and immunodeficient patients. A certain disadvantage of the available treatments is the lack of effectiveness against the tissue cyst of the parasite. A safe chemotherapy to combat toxoplasmosis should be based on the metabolic differences between the parasite and the mammalian host. This article covers different relevant molecular targets to combat this disease including the isoprenoid pathway (farnesyl diphosphate synthase, squalene synthase), dihydrofolate reductase, calcium-dependent protein kinases, histone deacetylase, mitochondrial electron transport chain, etc.
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Affiliation(s)
- Juan B Rodriguez
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Unidad de Microanálisis y Métodos Físicos en Química Orgánica (UMYMFOR), C1428EHA, Buenos Aires, Argentina.
| | - Sergio H Szajnman
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Unidad de Microanálisis y Métodos Físicos en Química Orgánica (UMYMFOR), C1428EHA, Buenos Aires, Argentina
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12
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Silva MF, Douglas K, Sandalli S, Maclean AE, Sheiner L. Functional and biochemical characterization of the Toxoplasma gondii succinate dehydrogenase complex. PLoS Pathog 2023; 19:e1011867. [PMID: 38079448 PMCID: PMC10735183 DOI: 10.1371/journal.ppat.1011867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 12/21/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
The mitochondrial electron transport chain (mETC) is a series of membrane embedded enzymatic complexes critical for energy conversion and mitochondrial metabolism. In commonly studied eukaryotes, including humans and animals, complex II, also known as succinate dehydrogenase (SDH), is an essential four-subunit enzyme that acts as an entry point to the mETC, by harvesting electrons from the TCA cycle. Apicomplexa are pathogenic parasites with significant impact on human and animal health. The phylum includes Toxoplasma gondii which can cause fatal infections in immunocompromised people. Most apicomplexans, including Toxoplasma, rely on their mETC for survival, yet SDH remains largely understudied. Previous studies pointed to a divergent apicomplexan SDH with nine subunits proposed for the Toxoplasma complex, compared to four in humans. While two of the nine are homologs of the well-studied SDHA and B, the other seven have no homologs in SDHs of other systems. Moreover, SDHC and D, that anchor SDH to the membrane and participate in substrate bindings, have no homologs in Apicomplexa. Here, we validated five of the seven proposed subunits as bona fide SDH components and demonstrated their importance for SDH assembly and activity. We further find that all five subunits are important for parasite growth, and that disruption of SDH impairs mitochondrial respiration and results in spontaneous initiation of differentiation into bradyzoites. Finally, we provide evidence that the five subunits are membrane bound, consistent with their potential role in membrane anchoring, and we demonstrate that a DY motif in one of them, SDH10, is essential for complex formation and function. Our study confirms the divergent composition of Toxoplasma SDH compared to human, and starts exploring the role of the lineage-specific subunits in SDH function, paving the way for future mechanistic studies.
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Affiliation(s)
- Mariana F. Silva
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Kiera Douglas
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Sofia Sandalli
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Andrew E. Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
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13
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Hayward JA, Makota FV, Cihalova D, Leonard RA, Rajendran E, Zwahlen SM, Shuttleworth L, Wiedemann U, Spry C, Saliba KJ, Maier AG, van Dooren GG. A screen of drug-like molecules identifies chemically diverse electron transport chain inhibitors in apicomplexan parasites. PLoS Pathog 2023; 19:e1011517. [PMID: 37471441 PMCID: PMC10403144 DOI: 10.1371/journal.ppat.1011517] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/04/2023] [Accepted: 06/28/2023] [Indexed: 07/22/2023] Open
Abstract
Apicomplexans are widespread parasites of humans and other animals, and include the causative agents of malaria (Plasmodium species) and toxoplasmosis (Toxoplasma gondii). Existing anti-apicomplexan therapies are beset with issues around drug resistance and toxicity, and new treatment options are needed. The mitochondrial electron transport chain (ETC) is one of the few processes that has been validated as a drug target in apicomplexans. To identify new inhibitors of the apicomplexan ETC, we developed a Seahorse XFe96 flux analyzer approach to screen the 400 compounds contained within the Medicines for Malaria Venture 'Pathogen Box' for ETC inhibition. We identified six chemically diverse, on-target inhibitors of the ETC in T. gondii, at least four of which also target the ETC of Plasmodium falciparum. Two of the identified compounds (MMV024937 and MMV688853) represent novel ETC inhibitor chemotypes. MMV688853 belongs to a compound class, the aminopyrazole carboxamides, that were shown previously to target a kinase with a key role in parasite invasion of host cells. Our data therefore reveal that MMV688853 has dual targets in apicomplexans. We further developed our approach to pinpoint the molecular targets of these inhibitors, demonstrating that all target Complex III of the ETC, with MMV688853 targeting the ubiquinone reduction (Qi) site of the complex. Most of the compounds we identified remain effective inhibitors of parasites that are resistant to Complex III inhibitors that are in clinical use or development, indicating that they could be used in treating drug resistant parasites. In sum, we have developed a versatile, scalable approach to screen for compounds that target the ETC in apicomplexan parasites, and used this to identify and characterize novel inhibitors.
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Affiliation(s)
- Jenni A. Hayward
- Research School of Biology, Australian National University, Canberra, Australia
| | - F. Victor Makota
- Research School of Biology, Australian National University, Canberra, Australia
| | - Daniela Cihalova
- Research School of Biology, Australian National University, Canberra, Australia
| | - Rachel A. Leonard
- Research School of Biology, Australian National University, Canberra, Australia
| | - Esther Rajendran
- Research School of Biology, Australian National University, Canberra, Australia
| | - Soraya M. Zwahlen
- Research School of Biology, Australian National University, Canberra, Australia
| | - Laura Shuttleworth
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ursula Wiedemann
- Research School of Biology, Australian National University, Canberra, Australia
| | - Christina Spry
- Research School of Biology, Australian National University, Canberra, Australia
| | - Kevin J. Saliba
- Research School of Biology, Australian National University, Canberra, Australia
| | - Alexander G. Maier
- Research School of Biology, Australian National University, Canberra, Australia
| | - Giel G. van Dooren
- Research School of Biology, Australian National University, Canberra, Australia
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14
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Leonard RA, Tian Y, Tan F, van Dooren GG, Hayward JA. An essential role for an Fe-S cluster protein in the cytochrome c oxidase complex of Toxoplasma parasites. PLoS Pathog 2023; 19:e1011430. [PMID: 37262100 PMCID: PMC10263302 DOI: 10.1371/journal.ppat.1011430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 06/13/2023] [Accepted: 05/17/2023] [Indexed: 06/03/2023] Open
Abstract
The mitochondrial electron transport chain (ETC) of apicomplexan parasites differs considerably from the ETC of the animals that these parasites infect, and is the target of numerous anti-parasitic drugs. The cytochrome c oxidase complex (Complex IV) of the apicomplexan Toxoplasma gondii ETC is more than twice the mass and contains subunits not found in human Complex IV, including a 13 kDa protein termed TgApiCox13. TgApiCox13 is homologous to a human iron-sulfur (Fe-S) cluster-containing protein called the mitochondrial inner NEET protein (HsMiNT) which is not a component of Complex IV in humans. Here, we establish that TgApiCox13 is a critical component of Complex IV in T. gondii, required for complex activity and stability. Furthermore, we demonstrate that TgApiCox13, like its human homolog, binds two Fe-S clusters. We show that the Fe-S clusters of TgApiCox13 are critical for ETC function, having an essential role in mediating Complex IV integrity. Our study provides the first functional characterisation of an Fe-S protein in Complex IV.
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Affiliation(s)
- Rachel A. Leonard
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Yuan Tian
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Feng Tan
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Giel G. van Dooren
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Jenni A. Hayward
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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15
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Espino-Sanchez T, Wienkers H, Marvin R, Nalder SA, García-Guerrero A, VanNatta P, Jami-Alahmadi Y, Mixon Blackwell A, Whitby F, Wohlschlegel J, Kieber-Emmons M, Hill C, A. Sigala P. Direct tests of cytochrome c and c1 functions in the electron transport chain of malaria parasites. Proc Natl Acad Sci U S A 2023; 120:e2301047120. [PMID: 37126705 PMCID: PMC10175771 DOI: 10.1073/pnas.2301047120] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/30/2023] [Indexed: 05/03/2023] Open
Abstract
The mitochondrial electron transport chain (ETC) of Plasmodium malaria parasites is a major antimalarial drug target, but critical cytochrome (cyt) functions remain unstudied and enigmatic. Parasites express two distinct cyt c homologs (c and c-2) with unusually sparse sequence identity and uncertain fitness contributions. P. falciparum cyt c-2 is the most divergent eukaryotic cyt c homolog currently known and has sequence features predicted to be incompatible with canonical ETC function. We tagged both cyt c homologs and the related cyt c1 for inducible knockdown. Translational repression of cyt c and cyt c1 was lethal to parasites, which died from ETC dysfunction and impaired ubiquinone recycling. In contrast, cyt c-2 knockdown or knockout had little impact on blood-stage growth, indicating that parasites rely fully on the more conserved cyt c for ETC function. Biochemical and structural studies revealed that both cyt c and c-2 are hemylated by holocytochrome c synthase, but UV-vis absorbance and EPR spectra strongly suggest that cyt c-2 has an unusually open active site in which heme is stably coordinated by only a single axial amino acid ligand and can bind exogenous small molecules. These studies provide a direct dissection of cytochrome functions in the ETC of malaria parasites and identify a highly divergent Plasmodium cytochrome c with molecular adaptations that defy a conserved role in eukaryotic evolution.
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Affiliation(s)
| | - Henry Wienkers
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | - Rebecca G. Marvin
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | - Shai-anne Nalder
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | | | - Peter E. VanNatta
- Department of Chemistry, University of Utah, Salt Lake City, UT84112
| | | | - Amanda Mixon Blackwell
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | - Frank G. Whitby
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | | | | | - Christopher P. Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT84112
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16
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Espino-Sanchez TJ, Wienkers H, Marvin RG, Nalder SA, García-Guerrero AE, VanNatta PE, Jami-Alahmadi Y, Blackwell AM, Whitby FG, Wohlschlegel JA, Kieber-Emmons MT, Hill CP, Sigala PA. Direct Tests of Cytochrome Function in the Electron Transport Chain of Malaria Parasites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.23.525242. [PMID: 36747727 PMCID: PMC9900762 DOI: 10.1101/2023.01.23.525242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The mitochondrial electron transport chain (ETC) of Plasmodium malaria parasites is a major antimalarial drug target, but critical cytochrome functions remain unstudied and enigmatic. Parasites express two distinct cyt c homologs ( c and c -2) with unusually sparse sequence identity and uncertain fitness contributions. P. falciparum cyt c -2 is the most divergent eukaryotic cyt c homolog currently known and has sequence features predicted to be incompatible with canonical ETC function. We tagged both cyt c homologs and the related cyt c 1 for inducible knockdown. Translational repression of cyt c and cyt c 1 was lethal to parasites, which died from ETC dysfunction and impaired ubiquinone recycling. In contrast, cyt c -2 knockdown or knock-out had little impact on blood-stage growth, indicating that parasites rely fully on the more conserved cyt c for ETC function. Biochemical and structural studies revealed that both cyt c and c -2 are hemylated by holocytochrome c synthase, but UV-vis absorbance and EPR spectra strongly suggest that cyt c -2 has an unusually open active site in which heme is stably coordinated by only a single axial amino-acid ligand and can bind exogenous small molecules. These studies provide a direct dissection of cytochrome functions in the ETC of malaria parasites and identify a highly divergent Plasmodium cytochrome c with molecular adaptations that defy a conserved role in eukaryotic evolution. SIGNIFICANCE STATEMENT Mitochondria are critical organelles in eukaryotic cells that drive oxidative metabolism. The mitochondrion of Plasmodium malaria parasites is a major drug target that has many differences from human cells and remains poorly studied. One key difference from humans is that malaria parasites express two cytochrome c proteins that differ significantly from each other and play untested and uncertain roles in the mitochondrial electron transport chain (ETC). Our study revealed that one cyt c is essential for ETC function and parasite viability while the second, more divergent protein has unusual structural and biochemical properties and is not required for growth of blood-stage parasites. This work elucidates key biochemical properties and evolutionary differences in the mitochondrial ETC of malaria parasites.
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Affiliation(s)
- Tanya J. Espino-Sanchez
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Henry Wienkers
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Rebecca G. Marvin
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Shai-anne Nalder
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Aldo E. García-Guerrero
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Peter E. VanNatta
- Department of Chemistry, University of Utah, Salt Lake City, UT, United States
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California, Los Angeles, CA, United States
| | - Amanda Mixon Blackwell
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Frank G. Whitby
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - James A. Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, CA, United States
| | | | - Christopher P. Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
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17
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Maclean AE, Hayward JA, Huet D, van Dooren GG, Sheiner L. The mystery of massive mitochondrial complexes: the apicomplexan respiratory chain. Trends Parasitol 2022; 38:1041-1052. [PMID: 36302692 PMCID: PMC10434753 DOI: 10.1016/j.pt.2022.09.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 11/05/2022]
Abstract
The mitochondrial respiratory chain is an essential pathway in most studied eukaryotes due to its roles in respiration and other pathways that depend on mitochondrial membrane potential. Apicomplexans are unicellular eukaryotes whose members have an impact on global health. The respiratory chain is a drug target for some members of this group, notably the malaria-causing Plasmodium spp. This has motivated studies of the respiratory chain in apicomplexan parasites, primarily Toxoplasma gondii and Plasmodium spp. for which experimental tools are most advanced. Studies of the respiratory complexes in these organisms revealed numerous novel features, including expansion of complex size. The divergence of apicomplexan mitochondria from commonly studied models highlights the diversity of mitochondrial form and function across eukaryotic life.
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Affiliation(s)
- Andrew E Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Jenni A Hayward
- Research School of Biology, Australian National University, Canberra, Australia
| | - Diego Huet
- Center for Tropical & Emerging Diseases, University of Georgia, Athens, GA, USA; Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, Australia
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK.
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18
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Herneisen AL, Li ZH, Chan AW, Moreno SNJ, Lourido S. Temporal and thermal profiling of the Toxoplasma proteome implicates parasite Protein Phosphatase 1 in the regulation of Ca 2+-responsive pathways. eLife 2022; 11:e80336. [PMID: 35976251 PMCID: PMC9436416 DOI: 10.7554/elife.80336] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Apicomplexan parasites cause persistent mortality and morbidity worldwide through diseases including malaria, toxoplasmosis, and cryptosporidiosis. Ca2+ signaling pathways have been repurposed in these eukaryotic pathogens to regulate parasite-specific cellular processes governing the replicative and lytic phases of the infectious cycle, as well as the transition between them. Despite the presence of conserved Ca2+-responsive proteins, little is known about how specific signaling elements interact to impact pathogenesis. We mapped the Ca2+-responsive proteome of the model apicomplexan Taxoplasma gondii via time-resolved phosphoproteomics and thermal proteome profiling. The waves of phosphoregulation following PKG activation and stimulated Ca2+ release corroborate known physiological changes but identify specific proteins operating in these pathways. Thermal profiling of parasite extracts identified many expected Ca2+-responsive proteins, such as parasite Ca2+-dependent protein kinases. Our approach also identified numerous Ca2+-responsive proteins that are not predicted to bind Ca2+, yet are critical components of the parasite signaling network. We characterized protein phosphatase 1 (PP1) as a Ca2+-responsive enzyme that relocalized to the parasite apex upon Ca2+ store release. Conditional depletion of PP1 revealed that the phosphatase regulates Ca2+ uptake to promote parasite motility. PP1 may thus be partly responsible for Ca2+-regulated serine/threonine phosphatase activity in apicomplexan parasites.
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Affiliation(s)
- Alice L Herneisen
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Biology Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases, University of GeorgiaAthensUnited States
| | - Alex W Chan
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Center for Tropical and Emerging Global Diseases, University of GeorgiaAthensUnited States
| | - Silvia NJ Moreno
- Center for Tropical and Emerging Global Diseases, University of GeorgiaAthensUnited States
| | - Sebastian Lourido
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Biology Department, Massachusetts Institute of TechnologyCambridgeUnited States
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19
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Disrupting the plastidic iron-sulfur cluster biogenesis pathway in Toxoplasma gondii has pleiotropic effects irreversibly impacting parasite viability. J Biol Chem 2022; 298:102243. [PMID: 35810787 PMCID: PMC9386495 DOI: 10.1016/j.jbc.2022.102243] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/27/2022] Open
Abstract
Like many other apicomplexan parasites, Toxoplasma gondii contains a plastid harboring key metabolic pathways, including the sulfur utilization factor (SUF) pathway that is involved in the biosynthesis of iron-sulfur clusters. These cofactors are crucial for a variety of proteins involved in important metabolic reactions, potentially including plastidic pathways for the synthesis of isoprenoid and fatty acids. It was shown previously that impairing the NFS2 cysteine desulfurase, involved in the first step of the SUF pathway, leads to an irreversible killing of intracellular parasites. However, the metabolic impact of disrupting the pathway remained unexplored. Here, we generated another mutant of this pathway, deficient in the SUFC ATPase, and investigated in details the phenotypic consequences of TgNFS2 and TgSUFC depletion on the parasites. Our analysis confirms that Toxoplasma SUF mutants are severely and irreversibly impacted in division and membrane homeostasis, and suggests a defect in apicoplast-generated fatty acids. However, we show that increased scavenging from the host or supplementation with exogenous fatty acids do not fully restore parasite growth, suggesting that this is not the primary cause for the demise of the parasites and that other important cellular functions were affected. For instance, we also show that the SUF pathway is key for generating the isoprenoid-derived precursors necessary for the proper targeting of GPI-anchored proteins and for parasite motility. Thus, we conclude plastid-generated iron-sulfur clusters support the functions of proteins involved in several vital downstream cellular pathways, which implies the SUF machinery may be explored for new potential anti-Toxoplasma targets.
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20
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Hayward JA, Rajendran E, Makota FV, Bassett BJ, Devoy M, Neeman T, van Dooren GG. Real-Time Analysis of Mitochondrial Electron Transport Chain Function in Toxoplasma gondii Parasites Using a Seahorse XFe96 Extracellular Flux Analyzer. Bio Protoc 2022; 12:e4288. [PMID: 35118179 PMCID: PMC8769764 DOI: 10.21769/bioprotoc.4288] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/04/2021] [Accepted: 11/07/2021] [Indexed: 07/22/2023] Open
Abstract
The mitochondrial electron transport chain (ETC) performs several critical biological functions, including maintaining mitochondrial membrane potential, serving as an electron sink for important metabolic pathways, and contributing to the generation of ATP via oxidative phosphorylation. The ETC is important for the survival of many eukaryotic organisms, including intracellular parasites such as the apicomplexan Toxoplasma gondii. The ETC of T. gondii and related parasites differs in several ways from the ETC of the mammalian host cells they infect, and can be targeted by anti-parasitic drugs, including the clinically used compound atovaquone. To characterize the function of novel ETC proteins found in the parasite and to identify new ETC inhibitors, a scalable assay that assesses both ETC function and non-mitochondrial parasite metabolism (e.g., glycolysis) is desirable. Here, we describe methods to measure the oxygen consumption rate (OCR) of intact T. gondii parasites and thereby assess ETC function, while simultaneously measuring the extracellular acidification rate (ECAR) as a measure of general parasite metabolism, using a Seahorse XFe96 extracellular flux analyzer. We also describe a method to pinpoint the location of ETC defects and/or the targets of inhibitors, using permeabilized T. gondii parasites. We have successfully used these methods to investigate the function of T. gondii proteins, including the apicomplexan parasite-specific protein subunit TgQCR11 of the coenzyme Q:cytochrome c oxidoreductase complex (ETC Complex III). We note that these methods are also amenable to screening compound libraries to identify candidate ETC inhibitors.
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Affiliation(s)
- Jenni A. Hayward
- Research School of Biology, Australian National University, Canberra, Australia
| | - Esther Rajendran
- Research School of Biology, Australian National University, Canberra, Australia
| | - F. Victor Makota
- Research School of Biology, Australian National University, Canberra, Australia
| | - Brad J. Bassett
- Research School of Biology, Australian National University, Canberra, Australia
| | - Michael Devoy
- Flow Cytometry Facility, The John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Teresa Neeman
- Biological Data Science Institute, The Australian National University, Canberra, Australia
| | - Giel G. van Dooren
- Research School of Biology, Australian National University, Canberra, Australia
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21
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Usey MM, Huet D. Parasite powerhouse: A review of the Toxoplasma gondii mitochondrion. J Eukaryot Microbiol 2022; 69:e12906. [PMID: 35315174 PMCID: PMC9490983 DOI: 10.1111/jeu.12906] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Toxoplasma gondii is a member of the apicomplexan phylum, a group of single-celled eukaryotic parasites that cause significant human morbidity and mortality around the world. T. gondii harbors two organelles of endosymbiotic origin: a non-photosynthetic plastid, known as the apicoplast, and a single mitochondrion derived from the ancient engulfment of an α-proteobacterium. Due to excitement surrounding the novelty of the apicoplast, the T. gondii mitochondrion was, to a certain extent, overlooked for about two decades. However, recent work has illustrated that the mitochondrion is an essential hub of apicomplexan-specific biology. Development of novel techniques, such as cryo-electron microscopy, complexome profiling, and next-generation sequencing have led to a renaissance in mitochondrial studies. This review will cover what is currently known about key features of the T. gondii mitochondrion, ranging from its genome to protein import machinery and biochemical pathways. Particular focus will be given to mitochondrial features that diverge significantly from the mammalian host, along with discussion of this important organelle as a drug target.
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Affiliation(s)
- Madelaine M. Usey
- Department of Cellular BiologyUniversity of GeorgiaAthensGeorgiaUSA,Center for Tropical and Emerging Global DiseasesUniversity of GeorgiaAthensGeorgiaUSA
| | - Diego Huet
- Center for Tropical and Emerging Global DiseasesUniversity of GeorgiaAthensGeorgiaUSA,Department of Pharmaceutical and Biomedical SciencesUniversity of GeorgiaAthensGeorgiaUSA
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Pamukcu S, Cerutti A, Bordat Y, Hem S, Rofidal V, Besteiro S. Differential contribution of two organelles of endosymbiotic origin to iron-sulfur cluster synthesis and overall fitness in Toxoplasma. PLoS Pathog 2021; 17:e1010096. [PMID: 34793583 PMCID: PMC8639094 DOI: 10.1371/journal.ppat.1010096] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/02/2021] [Accepted: 11/05/2021] [Indexed: 11/21/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are one of the most ancient and ubiquitous prosthetic groups, and they are required by a variety of proteins involved in important metabolic processes. Apicomplexan parasites have inherited different plastidic and mitochondrial Fe-S clusters biosynthesis pathways through endosymbiosis. We have investigated the relative contributions of these pathways to the fitness of Toxoplasma gondii, an apicomplexan parasite causing disease in humans, by generating specific mutants. Phenotypic analysis and quantitative proteomics allowed us to highlight notable differences in these mutants. Both Fe-S cluster synthesis pathways are necessary for optimal parasite growth in vitro, but their disruption leads to markedly different fates: impairment of the plastidic pathway leads to a loss of the organelle and to parasite death, while disruption of the mitochondrial pathway trigger differentiation into a stress resistance stage. This highlights that otherwise similar biochemical pathways hosted by different sub-cellular compartments can have very different contributions to the biology of the parasites, which is something to consider when exploring novel strategies for therapeutic intervention.
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Affiliation(s)
| | - Aude Cerutti
- LPHI, Univ Montpellier, CNRS, Montpellier, France
| | - Yann Bordat
- LPHI, Univ Montpellier, CNRS, Montpellier, France
| | - Sonia Hem
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Valérie Rofidal
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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Biochemical Studies of Mitochondrial Malate: Quinone Oxidoreductase from Toxoplasma gondii. Int J Mol Sci 2021; 22:ijms22157830. [PMID: 34360597 PMCID: PMC8345934 DOI: 10.3390/ijms22157830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/17/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis and infects almost one-third of the global human population. A lack of effective drugs and vaccines and the emergence of drug resistant parasites highlight the need for the development of new drugs. The mitochondrial electron transport chain (ETC) is an essential pathway for energy metabolism and the survival of T. gondii. In apicomplexan parasites, malate:quinone oxidoreductase (MQO) is a monotopic membrane protein belonging to the ETC and a key member of the tricarboxylic acid cycle, and has recently been suggested to play a role in the fumarate cycle, which is required for the cytosolic purine salvage pathway. In T. gondii, a putative MQO (TgMQO) is expressed in tachyzoite and bradyzoite stages and is considered to be a potential drug target since its orthologue is not conserved in mammalian hosts. As a first step towards the evaluation of TgMQO as a drug target candidate, in this study, we developed a new expression system for TgMQO in FN102(DE3)TAO, a strain deficient in respiratory cytochromes and dependent on an alternative oxidase. This system allowed, for the first time, the expression and purification of a mitochondrial MQO family enzyme, which was used for steady-state kinetics and substrate specificity analyses. Ferulenol, the only known MQO inhibitor, also inhibited TgMQO at IC50 of 0.822 μM, and displayed different inhibition kinetics compared to Plasmodium falciparum MQO. Furthermore, our analysis indicated the presence of a third binding site for ferulenol that is distinct from the ubiquinone and malate sites.
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Maclean AE, Bridges HR, Silva MF, Ding S, Ovciarikova J, Hirst J, Sheiner L. Complexome profile of Toxoplasma gondii mitochondria identifies divergent subunits of respiratory chain complexes including new subunits of cytochrome bc1 complex. PLoS Pathog 2021; 17:e1009301. [PMID: 33651838 PMCID: PMC7987180 DOI: 10.1371/journal.ppat.1009301] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/23/2021] [Accepted: 01/11/2021] [Indexed: 12/30/2022] Open
Abstract
The mitochondrial electron transport chain (mETC) and F1Fo-ATP synthase are of central importance for energy and metabolism in eukaryotic cells. The Apicomplexa, important pathogens of humans causing diseases such as toxoplasmosis and malaria, depend on their mETC in every known stage of their complicated life cycles. Here, using a complexome profiling proteomic approach, we have characterised the Toxoplasma mETC complexes and F1Fo-ATP synthase. We identified and assigned 60 proteins to complexes II, IV and F1Fo-ATP synthase of Toxoplasma, of which 16 have not been identified previously. Notably, our complexome profile elucidates the composition of the Toxoplasma complex III, the target of clinically used drugs such as atovaquone. We identified two new homologous subunits and two new parasite-specific subunits, one of which is broadly conserved in myzozoans. We demonstrate all four proteins are essential for complex III stability and parasite growth, and show their depletion leads to decreased mitochondrial potential, supporting their assignment as complex III subunits. Our study highlights the divergent subunit composition of the apicomplexan mETC and F1Fo-ATP synthase complexes and sets the stage for future structural and drug discovery studies.
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Affiliation(s)
- Andrew E. Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Hannah R. Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Mariana F. Silva
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Shujing Ding
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Jana Ovciarikova
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
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