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Arias Padilla LF, Lopez JM, Shibata A, Murray JM, Hu K. The initiation and early development of apical-basal polarity in Toxoplasma gondii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.14.603470. [PMID: 39071409 PMCID: PMC11275826 DOI: 10.1101/2024.07.14.603470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
The human parasite Toxoplasma gondii has a distinctive body plan with a well-defined polarity. In the apical complex, the minus ends of the 22 cortical microtubules are anchored to the apical polar ring, a putative microtubule-organizing center. The basal complex caps and constricts the parasite posterior end, and is critical for cytokinesis. How this apical-basal polarity axis is initiated was unknown. Here we examined the development of the apical polar ring and the basal complex in nascent daughters using expansion microscopy. We found that different substructures in the apical polar ring have different sensitivity to stress. In addition, apical-basal differentiation is already established upon nucleation of the cortical microtubule array: arc forms of the apical polar ring and basal complex associate with opposite ends of the microtubules. As the construction of the daughter framework progresses towards the centrioles, the apical and the basal arcs co-develop in striking synchrony ahead of the microtubule array, and close into a ring-form before all the microtubules are nucleated. We also found that two apical polar ring components, APR2 and KinesinA, act synergistically. The removal of each protein individually has modest to no impact on the lytic cycle. However, the loss of both results in abnormalities in the microtubule array and highly reduced plaquing and invasion efficiency.
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2
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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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3
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Engelberg K, Bauwens C, Ferguson DJP, Gubbels MJ. Co-dependent formation of the Toxoplasma gondii sub-pellicular microtubules and inner membrane skeleton. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.25.595886. [PMID: 38826480 PMCID: PMC11142238 DOI: 10.1101/2024.05.25.595886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
One of the defining features of apicomplexan parasites is their cytoskeleton composed of alveolar vesicles, known as the inner membrane complex (IMC) undergirded by intermediate-like filament network and an array of subpellicular microtubules (SPMTs). In Toxoplasma gondii, this specialized cytoskeleton is involved in all aspects of the disease-causing lytic cycle, and notably acting as a scaffold for parasite offspring in the internal budding process. Despite advances in our understanding of the architecture and molecular composition, insights pertaining to the coordinated assembly of the scaffold are still largely elusive. Here, T. gondii tachyzoites were dissected by advanced, iterative expansion microscopy (pan-ExM) revealing new insights into the very early sequential formation steps of the tubulin scaffold. A comparative study of the related parasite Sarcocystis neurona revealed that different MT bundling organizations of the nascent SPMTs correlate with the number of central and basal alveolar vesicles. In absence of a so far identified MT nucleation mechanism, we genetically dissected T. gondii γ-tubulin and γ-tubulin complex protein 4 (GCP4). While γ-tubulin depletion abolished the formation of the tubulin scaffold, a set of MTs still formed that suggests SPMTs are nucleated at the outer core of the centrosome. Depletion of GCP4 interfered with the correct assembly of SPMTs into the forming daughter buds, further indicating that the parasite utilizes the γ-tubulin complex in tubulin scaffold formation .
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Affiliation(s)
- Klemens Engelberg
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, USA
| | - Ciara Bauwens
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, USA
| | - David J. P. Ferguson
- Department of Biological and Medical Sciences, Oxford Brookes University, and NDCLS, Oxford University, Oxford, United Kingdom
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, USA
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4
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Tetzlaff S, Hillebrand A, Drakoulis N, Gluhic Z, Maschmann S, Lyko P, Wicke S, Schmitz-Linneweber C. Small RNAs from mitochondrial genome recombination sites are incorporated into T. gondii mitoribosomes. eLife 2024; 13:e95407. [PMID: 38363119 PMCID: PMC10948144 DOI: 10.7554/elife.95407] [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: 12/29/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
The mitochondrial genomes of apicomplexans comprise merely three protein-coding genes, alongside a set of thirty to forty genes encoding small RNAs (sRNAs), many of which exhibit homologies to rRNA from E. coli. The expression status and integration of these short RNAs into ribosomes remains unclear and direct evidence for active ribosomes within apicomplexan mitochondria is still lacking. In this study, we conducted small RNA sequencing on the apicomplexan Toxoplasma gondii to investigate the occurrence and function of mitochondrial sRNAs. To enhance the analysis of sRNA sequencing outcomes, we also re-sequenced the T. gondii mitochondrial genome using an improved organelle enrichment protocol and Nanopore sequencing. It has been established previously that the T. gondii genome comprises 21 sequence blocks that undergo recombination among themselves but that their order is not entirely random. The enhanced coverage of the mitochondrial genome allowed us to characterize block combinations at increased resolution. Employing this refined genome for sRNA mapping, we find that many small RNAs originated from the junction sites between protein-coding blocks and rRNA sequence blocks. Surprisingly, such block border sRNAs were incorporated into polysomes together with canonical rRNA fragments and mRNAs. In conclusion, apicomplexan ribosomes are active within polysomes and are indeed assembled through the integration of sRNAs, including previously undetected sRNAs with merged mRNA-rRNA sequences. Our findings lead to the hypothesis that T. gondii's block-based genome organization enables the dual utilization of mitochondrial sequences as both messenger RNAs and ribosomal RNAs, potentially establishing a link between the regulation of rRNA and mRNA expression.
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Affiliation(s)
| | | | | | - Zala Gluhic
- Molecular Genetics, Humboldt University BerlinBerlinGermany
| | | | - Peter Lyko
- Biodiversity and Evolution, Humboldt University BerlinBerlinGermany
| | - Susann Wicke
- Biodiversity and Evolution, Humboldt University BerlinBerlinGermany
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5
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Chan AW, Broncel M, Yifrach E, Haseley NR, Chakladar S, Andree E, Herneisen AL, Shortt E, Treeck M, Lourido S. Analysis of CDPK1 targets identifies a trafficking adaptor complex that regulates microneme exocytosis in Toxoplasma. eLife 2023; 12:RP85654. [PMID: 37933960 PMCID: PMC10629828 DOI: 10.7554/elife.85654] [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: 11/08/2023] Open
Abstract
Apicomplexan parasites use Ca2+-regulated exocytosis to secrete essential virulence factors from specialized organelles called micronemes. Ca2+-dependent protein kinases (CDPKs) are required for microneme exocytosis; however, the molecular events that regulate trafficking and fusion of micronemes with the plasma membrane remain unresolved. Here, we combine sub-minute resolution phosphoproteomics and bio-orthogonal labeling of kinase substrates in Toxoplasma gondii to identify 163 proteins phosphorylated in a CDPK1-dependent manner. In addition to known regulators of secretion, we identify uncharacterized targets with predicted functions across signaling, gene expression, trafficking, metabolism, and ion homeostasis. One of the CDPK1 targets is a putative HOOK activating adaptor. In other eukaryotes, HOOK homologs form the FHF complex with FTS and FHIP to activate dynein-mediated trafficking of endosomes along microtubules. We show the FHF complex is partially conserved in T. gondii, consisting of HOOK, an FTS homolog, and two parasite-specific proteins (TGGT1_306920 and TGGT1_316650). CDPK1 kinase activity and HOOK are required for the rapid apical trafficking of micronemes as parasites initiate motility. Moreover, parasites lacking HOOK or FTS display impaired microneme protein secretion, leading to a block in the invasion of host cells. Taken together, our work provides a comprehensive catalog of CDPK1 targets and reveals how vesicular trafficking has been tuned to support a parasitic lifestyle.
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Affiliation(s)
- Alex W Chan
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Biology Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Malgorzata Broncel
- Signaling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Eden Yifrach
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
| | - Nicole R Haseley
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
| | | | - Elena Andree
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
| | - Alice L Herneisen
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Biology Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Emily Shortt
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
| | - Moritz Treeck
- Signaling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Sebastian Lourido
- Whitehead Institute for Biomedical ResearchCambridgeUnited States
- Biology Department, Massachusetts Institute of TechnologyCambridgeUnited States
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6
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Chan AW, Broncel M, Yifrach E, Haseley N, Chakladar S, Andree E, Herneisen AL, Shortt E, Treeck M, Lourido S. Analysis of CDPK1 targets identifies a trafficking adaptor complex that regulates microneme exocytosis in Toxoplasma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523553. [PMID: 36712004 PMCID: PMC9882037 DOI: 10.1101/2023.01.11.523553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Apicomplexan parasites use Ca2+-regulated exocytosis to secrete essential virulence factors from specialized organelles called micronemes. Ca2+-dependent protein kinases (CDPKs) are required for microneme exocytosis; however, the molecular events that regulate trafficking and fusion of micronemes with the plasma membrane remain unresolved. Here, we combine sub-minute resolution phosphoproteomics and bio-orthogonal labeling of kinase substrates in Toxoplasma gondii to identify 163 proteins phosphorylated in a CDPK1-dependent manner. In addition to known regulators of secretion, we identify uncharacterized targets with predicted functions across signaling, gene expression, trafficking, metabolism, and ion homeostasis. One of the CDPK1 targets is a putative HOOK activating adaptor. In other eukaryotes, HOOK homologs form the FHF complex with FTS and FHIP to activate dynein-mediated trafficking of endosomes along microtubules. We show the FHF complex is partially conserved in T. gondii, consisting of HOOK, an FTS homolog, and two parasite-specific proteins (TGGT1_306920 and TGGT1_316650). CDPK1 kinase activity and HOOK are required for the rapid apical trafficking of micronemes as parasites initiate motility. Moreover, parasites lacking HOOK or FTS display impaired microneme protein secretion, leading to a block in the invasion of host cells. Taken together, our work provides a comprehensive catalog of CDPK1 targets and reveals how vesicular trafficking has been tuned to support a parasitic lifestyle.
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Affiliation(s)
- Alex W Chan
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Malgorzata Broncel
- Signaling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, UK
| | - Eden Yifrach
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Nicole Haseley
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | | | - Elena Andree
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Alice L Herneisen
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Emily Shortt
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Moritz Treeck
- Signaling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, UK
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, USA
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7
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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 DOI: 10.1371/journal.ppat.1011430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [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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8
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Li Z, Du W, Yang J, Lai DH, Lun ZR, Guo Q. Cryo-Electron Tomography of Toxoplasma gondii Indicates That the Conoid Fiber May Be Derived from Microtubules. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206595. [PMID: 36840635 DOI: 10.1002/advs.202206595] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/04/2023] [Indexed: 05/18/2023]
Abstract
Toxoplasma gondii (T. gondii) is the causative agent of toxoplasmosis and can infect numerous warm-blooded animals. An improved understanding of the fine structure of this parasite can help elucidate its replication mechanism. Previous studies have resolved the ultrastructure of the cytoskeleton using purified samples, which eliminates their cellular context. Here the application of cryo-electron tomography to visualize T. gondii tachyzoites in their native state is reported. The fine structure and cellular distribution of the cytoskeleton are resolved and analyzed at nanometer resolution. Additionally, the tachyzoite structural characteristics are annotated during its endodyogeny for the first time. By comparing the structural features in mature tachyzoites and their daughter buds, it is proposed that the conoid fiber of the Apicomplexa originates from microtubules. This work represents the detailed molecular anatomy of T. gondii, particularly during the budding replication stage of tachyzoite, and provides a reference for further studies of this fascinating organism.
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Affiliation(s)
- Zhixun Li
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, 100871, P. R. China
| | - Wenjing Du
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, 100871, P. R. China
| | - Jiong Yang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| | - De-Hua Lai
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| | - Zhao-Rong Lun
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| | - Qiang Guo
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, 100871, P. R. China
- Changping Laboratory, Yard 28, Science Park Road, Beijing, 102206, P. R. China
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9
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Dubois DJ, Chehade S, Marq JB, Venugopal K, Maco B, Puig ATI, Soldati-Favre D, Marion S. Toxoplasma gondii HOOK-FTS-HIP Complex is Critical for Secretory Organelle Discharge during Motility, Invasion, and Egress. mBio 2023:e0045823. [PMID: 37093045 DOI: 10.1128/mbio.00458-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
Members of the Apicomplexa phylum possess specialized secretory organelles that discharge, apically and in a timely regulated manner, key factors implicated in parasite motility, host cell invasion, egress and subversion of host cellular functions. The mechanisms regulating trafficking and apical docking of these secretory organelles are only partially elucidated. Here, we characterized two conserved endosomal trafficking regulators known to promote vesicle transport and/or fusion, HOOK and Fused Toes (FTS), in the context of organelle discharge in Toxoplasma gondii. TgHOOK and TgFTS form a complex with a coccidian-specific partner, named HOOK interacting partner (HIP). TgHOOK displays an apically enriched vesicular pattern and concentrates at the parasite apical tip where it colocalizes with TgFTS and TgHIP. Functional investigations revealed that TgHOOK is dispensable but fitness conferring. The protein regulates the apical positioning and secretion of micronemes and contributes to egress, motility, host cell attachment, and invasion. Conditional depletion of TgFTS or TgHIP impacted on the same processes but led to more severe phenotypes. This study provides evidence of endosomal trafficking regulators involved in the apical exocytosis of micronemes and possibly as a consequence or directly on the discharge of the rhoptries. IMPORTANCE Toxoplasma gondii affects between 30 and 80% of the human population, poses a life-threatening risk to immunocompromised individuals, and is a cause of abortion and birth defects following congenital transmission. T. gondii belongs to the phylum of Apicomplexa characterized by a set of unique apical secretory organelles called the micronemes and rhoptries. Upon host cell recognition, this obligatory intracellular parasite secretes specific effectors contained in micronemes and rhoptries to promote parasite invasion of host cells and subsequent persistence. Here, we identified novel T. gondii endosomal trafficking regulators and demonstrated that they regulate microneme organelle apical positioning and exocytosis, thereby strongly contributing to host cell invasion and parasite virulence.
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Affiliation(s)
- David J Dubois
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Sylia Chehade
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Kannan Venugopal
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Albert Tell I Puig
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Sabrina Marion
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
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10
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Gui L, O'Shaughnessy WJ, Cai K, Reetz E, Reese ML, Nicastro D. Cryo-tomography reveals rigid-body motion and organization of apicomplexan invasion machinery. Nat Commun 2023; 14:1775. [PMID: 36997532 PMCID: PMC10063558 DOI: 10.1038/s41467-023-37327-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and toxoplasmosis. Its structure and mechanism of motion are poorly understood. We used cryo-FIB-milling and cryo-electron tomography to visualize the 3D-structure of the apical complex in its protruded and retracted states. Averages of conoid-fibers revealed their polarity and unusual nine-protofilament arrangement with associated proteins connecting and likely stabilizing the fibers. Neither the structure of the conoid-fibers nor the architecture of the spiral-shaped conoid complex change during protrusion or retraction. Thus, the conoid moves as a rigid body, and is not spring-like and compressible, as previously suggested. Instead, the apical-polar-rings (APR), previously considered rigid, dilate during conoid protrusion. We identified actin-like filaments connecting the conoid and APR during protrusion, suggesting a role during conoid movements. Furthermore, our data capture the parasites in the act of secretion during conoid protrusion.
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Affiliation(s)
- Long Gui
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - William J O'Shaughnessy
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Kai Cai
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Evan Reetz
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Michael L Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
- Department of Biochemistry, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
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11
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Howieson VM, Zeng J, Kloehn J, Spry C, Marchetti C, Lunghi M, Varesio E, Soper A, Coyne AG, Abell C, van Dooren GG, Saliba KJ. Pantothenate biosynthesis in Toxoplasma gondii tachyzoites is not a drug target. INTERNATIONAL JOURNAL FOR PARASITOLOGY: DRUGS AND DRUG RESISTANCE 2023; 22:1-8. [PMID: 37004488 PMCID: PMC10102396 DOI: 10.1016/j.ijpddr.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/08/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023]
Abstract
Toxoplasma gondii is a pervasive apicomplexan parasite that can cause severe disease and death in immunocompromised individuals and the developing foetus. The treatment of toxoplasmosis often leads to serious side effects and novel drugs and drug targets are therefore actively sought. In 2014, Mageed and colleagues suggested that the T. gondii pantothenate synthetase, the enzyme responsible for the synthesis of the vitamin B5 (pantothenate), the precursor of the important cofactor, coenzyme A, is a good drug target. Their conclusion was based on the ability of potent inhibitors of the M. tuberculosis pantothenate synthetase to inhibit the proliferation of T. gondii tachyzoites. They also reported that the inhibitory effect of the compounds could be antagonised by supplementing the medium with pantothenate, supporting their conclusion that the compounds were acting on the intended target. Contrary to these observations, we find that compound SW314, one of the compounds used in the Mageed et al. study and previously shown to be active against M. tuberculosis pantothenate synthetase in vitro, is inactive against the T. gondii pantothenate synthetase and does not inhibit tachyzoite proliferation, despite gaining access into the parasite in situ. Furthermore, we validate the recent observation that the pantothenate synthetase gene in T. gondii can be disrupted without detrimental effect to the survival of the tachyzoite-stage parasite in the presence or absence of extracellular pantothenate. We conclude that the T. gondii pantothenate synthetase is not essential during the tachyzoite stage of the parasite and it is therefore not a target for drug discovery against T. gondii tachyzoites.
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12
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Haase R, Dos Santos Pacheco N, Soldati-Favre D. Nanoscale imaging of the conoid and functional dissection of its dynamics in Apicomplexa. Curr Opin Microbiol 2022; 70:102226. [PMID: 36332501 DOI: 10.1016/j.mib.2022.102226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/08/2022]
Abstract
Members of the Apicomplexa phylum are unified by an apical complex tailored for motility and host cell invasion. It includes regulated secretory organelles and a conoid attached to the apical polar ring (APR) from which subpellicular microtubules emerge. In coccidia, the conoid is composed of a cone of spiraling tubulin fibers, two preconoidal rings, and two intraconoidal microtubules. The conoid extrudes through the APR in motile parasites. Recent advances in proteomics, cryo-electron tomography, super-resolution, and expansion microscopy provide a more comprehensive view of the spatial and temporal resolution of proteins belonging to the conoid subcomponents. In combination with the phenotyping of targeted mutants, the biogenesis, turnover, dynamics, and function of the conoid begin to be elucidated.
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Affiliation(s)
- Romuald Haase
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Nicolas Dos Santos Pacheco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland.
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13
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The Porifera microeukaryome: Addressing the neglected associations between sponges and protists. Microbiol Res 2022; 265:127210. [PMID: 36183422 DOI: 10.1016/j.micres.2022.127210] [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: 05/02/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/22/2022]
Abstract
While bacterial and archaeal communities of sponges are intensively studied, given their importance to the animal's physiology as well as sources of several new bioactive molecules, the potential and roles of associated protists remain poorly known. Historically, culture-dependent approaches dominated the investigations of sponge-protist interactions. With the advances in omics techniques, these associations could be visualized at other equally important scales. Of the few existing studies, there is a strong tendency to focus on interactions with photosynthesizing taxa such as dinoflagellates and diatoms, with fewer works dissecting the interactions with other less common groups. In addition, there are bottlenecks and inherent biases in using primer pairs and bioinformatics approaches in the most commonly used metabarcoding studies. Thus, this review addresses the issues underlying this association, using the term "microeukaryome" to refer exclusively to protists associated with an animal host. We aim to highlight the diversity and community composition of protists associated with sponges and place them on the same level as other microorganisms already well studied in this context. Among other shortcomings, it could be observed that the biotechnological potential of the microeukaryome is still largely unexplored, possibly being a valuable source of new pharmacological compounds, enzymes and metabolic processes.
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14
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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; 11:80336. [PMID: 35976251 PMCID: PMC9436416 DOI: 10.7554/elife.80336] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [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 T. 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 Research, Cambridge, United States
| | - Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, United States
| | - Alex W Chan
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Silvia N J Moreno
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, United States
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, United States
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15
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Burrell A, Marugan-Hernandez V, Wheeler R, Moreira-Leite F, Ferguson DJP, Tomley FM, Vaughan S. Cellular electron tomography of the apical complex in the apicomplexan parasite Eimeria tenella shows a highly organised gateway for regulated secretion. PLoS Pathog 2022; 18:e1010666. [PMID: 35816515 PMCID: PMC9302750 DOI: 10.1371/journal.ppat.1010666] [Citation(s) in RCA: 7] [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: 09/10/2021] [Revised: 07/21/2022] [Accepted: 06/12/2022] [Indexed: 11/18/2022] Open
Abstract
The apical complex of apicomplexan parasites is essential for host cell invasion and intracellular survival and as the site of regulated exocytosis from specialised secretory organelles called rhoptries and micronemes. Despite its importance, there are few data on the three-dimensional organisation and quantification of these organelles within the apical complex or how they are trafficked to this specialised region of plasma membrane for exocytosis. In coccidian apicomplexans there is an additional tubulin-containing hollow barrel structure, the conoid, which provides a structural gateway for this specialised apical secretion. Using a combination of cellular electron tomography and serial block face-scanning electron microscopy (SBF-SEM) we have reconstructed the entire apical end of Eimeria tenella sporozoites; we report a detailed dissection of the three- dimensional organisation of the conoid and show there is high curvature of the tubulin-containing fibres that might be linked to the unusual comma-shaped arrangement of protofilaments. We quantified the number and location of rhoptries and micronemes within cells and show a highly organised gateway for trafficking and docking of rhoptries, micronemes and microtubule-associated vesicles within the conoid around a set of intra-conoidal microtubules. Finally, we provide ultrastructural evidence for fusion of rhoptries directly through the parasite plasma membrane early in infection and the presence of a pore in the parasitophorous vacuole membrane, providing a structural explanation for how rhoptry proteins may be trafficked between the parasite and the host cytoplasm.
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Affiliation(s)
- Alana Burrell
- The Royal Veterinary College, University of London, North Mymms, United Kingdom
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | | | - Richard Wheeler
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Flavia Moreira-Leite
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - David J. P. Ferguson
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Fiona M. Tomley
- The Royal Veterinary College, University of London, North Mymms, United Kingdom
- * E-mail: (FMT); (SV)
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- * E-mail: (FMT); (SV)
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16
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A comprehensive ultrastructural analysis of the Toxoplasma gondii cytoskeleton. Parasitol Res 2022; 121:2065-2078. [PMID: 35524789 DOI: 10.1007/s00436-022-07534-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
Abstract
The invasive nature of Toxoplasma gondii is closely related to the properties of its cytoskeleton, which is constituted by a group of diverse structural and dynamic components that play key roles during the infection. Even if there have been numerous reports about the composition and function of the Toxoplasma cytoskeleton, the ultrastructural organization of some of these components has not yet been fully characterized. This study used a detergent extraction process and several electron microscopy contrast methods that allowed the successful isolation of the cytoskeleton of Toxoplasma tachyzoites. This process allowed for the conservation of the structures known to date and several new structures that had not been characterized at the ultrastructural level. For the first time, characterization was achieved for a group of nanofibers that allow the association between the polar apical ring and the conoid as well as the ultrastructural characterization of the apical cap of the parasite. The ultrastructure and precise location of the peripheral rings were also found, and the annular components of the basal complex were characterized. Finally, through immunoelectron microscopy, the exact spatial location of the subpellicular network inside the internal membrane system that forms the pellicle was found. The findings regarding these new structures contribute to the knowledge concerning the biology of the Toxoplasma gondii cytoskeleton. They also provide new opportunities in the search for therapeutic strategies aimed at these components with the purpose of inhibiting invasion and thus parasitism.
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17
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Cryo-ET of Toxoplasma parasites gives subnanometer insight into tubulin-based structures. Proc Natl Acad Sci U S A 2022; 119:2111661119. [PMID: 35121661 PMCID: PMC8832990 DOI: 10.1073/pnas.2111661119] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2021] [Indexed: 11/18/2022] Open
Abstract
Tubulin polymers are essential for a variety of cellular functions. Using cryo-ET, we reveal the 3D organization of the apical complex in Toxoplasma gondii, an intracellular eukaryote with tubulin-based structures, including an apical “conoid” involved in host cell invasion. Our development of an advanced subtomogram averaging protocol for filamentous structures enabled us to accurately assign tubulins in cellular context. At the subnanometer resolution achieved, tubulins were confirmed to assemble into two major forms: canonical subpellicular microtubules (SPMTs) and noncanonical conoid fibrils (CFs). The data further revealed associated proteins in both structures, a dominant orientation of SPMTs, and a unique patterning of the CFs. This work demonstrates an approach that can be used to determine cellular filamentous structures at multiscale resolutions. Tubulin is a conserved protein that polymerizes into different forms of filamentous structures in Toxoplasma gondii, an obligate intracellular parasite in the phylum Apicomplexa. Two key tubulin-containing cytoskeletal components are subpellicular microtubules (SPMTs) and conoid fibrils (CFs). The SPMTs help maintain shape and gliding motility, while the CFs are implicated in invasion. Here, we use cryogenic electron tomography to determine the molecular structures of the SPMTs and CFs in vitrified intact and detergent-extracted parasites. Subvolume densities from detergent-extracted parasites yielded averaged density maps at subnanometer resolutions, and these were related back to their architecture in situ. An intralumenal spiral lines the interior of the 13-protofilament SPMTs, revealing a preferred orientation of these microtubules relative to the parasite’s long axis. Each CF is composed of nine tubulin protofilaments that display a comma-shaped cross-section, plus additional associated components. Conoid protrusion, a crucial step in invasion, is associated with an altered pitch of each CF. The use of basic building blocks of protofilaments and different accessory proteins in one organism illustrates the versatility of tubulin to form two distinct types of assemblies, SPMTs and CFs.
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18
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Tomasina R, González FC, Francia ME. Structural and Functional Insights into the Microtubule Organizing Centers of Toxoplasma gondii and Plasmodium spp. Microorganisms 2021; 9:2503. [PMID: 34946106 PMCID: PMC8705618 DOI: 10.3390/microorganisms9122503] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 12/23/2022] Open
Abstract
Microtubule organizing centers (MTOCs) perform critical cellular tasks by nucleating, stabilizing, and anchoring microtubule's minus ends. These capacities impact tremendously a wide array of cellular functions ranging from ascribing cell shape to orchestrating cell division and generating motile structures, among others. The phylum Apicomplexa comprises over 6000 single-celled obligate intracellular parasitic species. Many of the apicomplexan are well known pathogens such as Toxoplasma gondii and the Plasmodium species, causative agents of toxoplasmosis and malaria, respectively. Microtubule organization in these parasites is critical for organizing the cortical cytoskeleton, enabling host cell penetration and the positioning of large organelles, driving cell division and directing the formation of flagella in sexual life stages. Apicomplexans are a prime example of MTOC diversity displaying multiple functional and structural MTOCs combinations within a single species. This diversity can only be fully understood in light of each organism's specific MT nucleation requirements and their evolutionary history. Insight into apicomplexan MTOCs had traditionally been limited to classical ultrastructural work by transmission electron microscopy. However, in the past few years, a large body of molecular insight has emerged. In this work we describe the latest insights into nuclear MTOC biology in two major human and animal disease causing Apicomplexans: Toxoplasma gondii and Plasmodium spp.
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Affiliation(s)
- Ramiro Tomasina
- Laboratory of Apicomplexan Biology, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay; (R.T.); (F.C.G.)
- Departamento de Parasitología y Micología, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | - Fabiana C. González
- Laboratory of Apicomplexan Biology, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay; (R.T.); (F.C.G.)
- Departamento de Parasitología y Micología, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | - Maria E. Francia
- Laboratory of Apicomplexan Biology, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay; (R.T.); (F.C.G.)
- Departamento de Parasitología y Micología, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
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19
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Dos Santos Pacheco N, Tosetti N, Krishnan A, Haase R, Maco B, Suarez C, Ren B, Soldati-Favre D. Revisiting the Role of Toxoplasma gondii ERK7 in the Maintenance and Stability of the Apical Complex. mBio 2021; 12:e0205721. [PMID: 34607461 PMCID: PMC8546650 DOI: 10.1128/mbio.02057-21] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/02/2021] [Indexed: 12/02/2022] Open
Abstract
Toxoplasma gondii extracellular signal-regulated kinase 7 (ERK7) is known to contribute to the integrity of the apical complex and to participate in the final step of conoid biogenesis. In the absence of ERK7, mature parasites lose their conoid complex and are unable to glide, invade, or egress from host cells. In contrast to a previous report, we show here that the depletion of ERK7 phenocopies the depletion of the apical cap protein AC9 or AC10. The absence of ERK7 leads to the loss of the apical polar ring (APR), the disorganization of the basket of subpellicular microtubules (SPMTs), and a severe impairment in microneme secretion. Ultrastructure expansion microscopy (U-ExM), coupled to N-hydroxysuccinimide ester (NHS-ester) staining on intracellular parasites, offers an unprecedented level of resolution and highlights the disorganization of the rhoptries as well as the dilated plasma membrane at the apical pole in the absence of ERK7. Comparative proteomics analysis of wild-type and ERK7-depleted parasites confirmed the disappearance of known apical complex proteins, including markers of the apical polar ring and a new apical cap named AC11. Concomitantly, the absence of ERK7 led to an accumulation of microneme proteins, resulting from the defect in the exocytosis of the organelles. AC9-depleted parasites were included as controls and exhibited an increase in inner membrane complex proteins, with two new proteins assigned to this compartment, namely, IMC33 and IMC34. IMPORTANCE The conoid is an enigmatic, dynamic organelle positioned at the apical tip of the coccidian subgroup of the Apicomplexa, close to the apical polar ring (APR) from which the subpellicular microtubules (SPMTs) emerge and through which the secretory organelles (micronemes and rhoptries) reach the plasma membrane for exocytosis. In Toxoplasma gondii, the conoid protrudes concomitantly with microneme secretion, during egress, motility, and invasion. The conditional depletion of the apical cap structural protein AC9 or AC10 leads to a disorganization of SPMTs as well as the loss of the APR and conoid, resulting in a microneme secretion defect and a block in motility, invasion, and egress. We show here that the depletion of the kinase ERK7 phenocopies AC9 and AC10 mutants. The combination of ultrastructure expansion microscopy and NHS-ester staining revealed that ERK7-depleted parasites exhibit a dilated apical plasma membrane and an altered positioning of the rhoptries, while electron microscopy images unambiguously highlight the loss of the APR.
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Affiliation(s)
- Nicolas Dos Santos Pacheco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nicolò Tosetti
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Aarti Krishnan
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Romuald Haase
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Catherine Suarez
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Bingjian Ren
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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20
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Affiliation(s)
- Paula MacGregor
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
| | | | - R. Ellen R. Nisbet
- School of Bioscience, University of Nottingham, Nottingham, United Kingdom
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21
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Fairweather SJ, Rajendran E, Blume M, Javed K, Steinhöfel B, McConville MJ, Kirk K, Bröer S, van Dooren GG. Coordinated action of multiple transporters in the acquisition of essential cationic amino acids by the intracellular parasite Toxoplasma gondii. PLoS Pathog 2021; 17:e1009835. [PMID: 34432856 PMCID: PMC8423306 DOI: 10.1371/journal.ppat.1009835] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/07/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
Intracellular parasites of the phylum Apicomplexa are dependent on the scavenging of essential amino acids from their hosts. We previously identified a large family of apicomplexan-specific plasma membrane-localized amino acid transporters, the ApiATs, and showed that the Toxoplasma gondii transporter TgApiAT1 functions in the selective uptake of arginine. TgApiAT1 is essential for parasite virulence, but dispensable for parasite growth in medium containing high concentrations of arginine, indicating the presence of at least one other arginine transporter. Here we identify TgApiAT6-1 as the second arginine transporter. Using a combination of parasite assays and heterologous characterisation of TgApiAT6-1 in Xenopus laevis oocytes, we demonstrate that TgApiAT6-1 is a general cationic amino acid transporter that mediates both the high-affinity uptake of lysine and the low-affinity uptake of arginine. TgApiAT6-1 is the primary lysine transporter in the disease-causing tachyzoite stage of T. gondii and is essential for parasite proliferation. We demonstrate that the uptake of cationic amino acids by TgApiAT6-1 is ‘trans-stimulated’ by cationic and neutral amino acids and is likely promoted by an inwardly negative membrane potential. These findings demonstrate that T. gondii has evolved overlapping transport mechanisms for the uptake of essential cationic amino acids, and we draw together our findings into a comprehensive model that highlights the finely-tuned, regulated processes that mediate cationic amino acid scavenging by these intracellular parasites. The causative agent of toxoplasmosis, Toxoplasma gondii, is a versatile intracellular parasite that can proliferate within nucleated cells of warm-blooded organisms. In order to survive, T. gondii parasites must scavenge the cationic amino acids lysine and arginine from their hosts. In a previous study, we demonstrated that a plasma membrane-localized protein called TgApiAT1 facilitates the uptake of arginine into the parasite. We found that parasites lacking TgApiAT1 could proliferate when cultured in medium containing high concentrations of arginine, suggesting the existence of an additional uptake pathway for arginine. In the present study, we demonstrate that this second uptake pathway is mediated by TgApiAT6-1, a protein belonging to the same solute transporter family as TgApiAT1. We show that TgApiAT6-1 is the major lysine transporter of the parasite, and that it is critical for parasite proliferation. Furthermore, we demonstrate that TgApiAT6-1 can transport arginine into parasites under conditions in which arginine concentrations are high and lysine concentrations are comparatively lower. These data support a model for the finely-tuned acquisition of essential cationic amino acids that involves multiple transporters, and which likely contributes to these parasites being able to survive and proliferate within a wide variety of host cell types.
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Affiliation(s)
- Stephen J. Fairweather
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (SJF); (GGvD)
| | - Esther Rajendran
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Martin Blume
- Department of Biochemistry and Molecular Biology and the Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
- Robert Koch Institute, Berlin, Germany
| | - Kiran Javed
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Birte Steinhöfel
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- Humboldt University Berlin, Berlin, Germany
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology and the Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Stefan Bröer
- 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
- * E-mail: (SJF); (GGvD)
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22
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More K, Klinger CM, Barlow LD, Dacks JB. Evolution and Natural History of Membrane Trafficking in Eukaryotes. Curr Biol 2021; 30:R553-R564. [PMID: 32428497 DOI: 10.1016/j.cub.2020.03.068] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The membrane-trafficking system is a defining facet of eukaryotic cells. The best-known organelles and major protein families of this system are largely conserved across the vast diversity of eukaryotes, implying both ancient organization and functional unity. Nonetheless, intriguing variation exists that speaks to the evolutionary forces that have shaped the endomembrane system in eukaryotes and highlights ways in which membrane trafficking in protists differs from that in our well-understood models of mammalian and yeast cells. Both parasites and free-living protists possess specialized trafficking organelles, some lineage specific, others more widely distributed - the evolution and function of these organelles begs exploration. Novel members of protein families are present across eukaryotes but have been lost in humans. These proteins may well hold clues to understanding differences in cellular function in organisms that are of pressing importance for planetary health.
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Affiliation(s)
- Kira More
- Division of Infectious Disease, Department of Medicine, University of Alberta, 1-124 Clinical Sciences Building, 11350-83 Avenue, Edmonton, Alberta T6G 2G3, Canada; Department of Biological Sciences, University of Alberta, P217 Biological Sciences Building, Edmonton, Alberta T6G 2E9, Canada
| | - Christen M Klinger
- Division of Infectious Disease, Department of Medicine, University of Alberta, 1-124 Clinical Sciences Building, 11350-83 Avenue, Edmonton, Alberta T6G 2G3, Canada
| | - Lael D Barlow
- Division of Infectious Disease, Department of Medicine, University of Alberta, 1-124 Clinical Sciences Building, 11350-83 Avenue, Edmonton, Alberta T6G 2G3, Canada; Department of Biological Sciences, University of Alberta, P217 Biological Sciences Building, Edmonton, Alberta T6G 2E9, Canada
| | - Joel B Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, 1-124 Clinical Sciences Building, 11350-83 Avenue, Edmonton, Alberta T6G 2G3, Canada; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic.
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23
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Dass S, Shunmugam S, Berry L, Arnold CS, Katris NJ, Duley S, Pierrel F, Cesbron-Delauw MF, Yamaryo-Botté Y, Botté CY. Toxoplasma LIPIN is essential in channeling host lipid fluxes through membrane biogenesis and lipid storage. Nat Commun 2021; 12:2813. [PMID: 34001876 PMCID: PMC8129101 DOI: 10.1038/s41467-021-22956-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/24/2021] [Indexed: 01/20/2023] Open
Abstract
Apicomplexa are obligate intracellular parasites responsible for major human diseases. Their intracellular survival relies on intense lipid synthesis, which fuels membrane biogenesis. Parasite lipids are generated as an essential combination of fatty acids scavenged from the host and de novo synthesized within the parasite apicoplast. The molecular and metabolic mechanisms allowing regulation and channeling of these fatty acid fluxes for intracellular parasite survival are currently unknown. Here, we identify an essential phosphatidic acid phosphatase in Toxoplasma gondii, TgLIPIN, as the central metabolic nexus responsible for controlled lipid synthesis sustaining parasite development. Lipidomics reveal that TgLIPIN controls the synthesis of diacylglycerol and levels of phosphatidic acid that regulates the fine balance of lipids between storage and membrane biogenesis. Using fluxomic approaches, we uncover the first parasite host-scavenged lipidome and show that TgLIPIN prevents parasite death by 'lipotoxicity' through effective channeling of host-scavenged fatty acids to storage triacylglycerols and membrane phospholipids.
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Affiliation(s)
- Sheena Dass
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Serena Shunmugam
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Laurence Berry
- Laboratory of Pathogen Host Interactions, UMR 5235, Université de Montpellier, Montpellier, France
| | - Christophe-Sebastien Arnold
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Nicholas J Katris
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Samuel Duley
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Fabien Pierrel
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Marie-France Cesbron-Delauw
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Yoshiki Yamaryo-Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France.
| | - Cyrille Y Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France.
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24
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Morano AA, Dvorin JD. The Ringleaders: Understanding the Apicomplexan Basal Complex Through Comparison to Established Contractile Ring Systems. Front Cell Infect Microbiol 2021; 11:656976. [PMID: 33954122 PMCID: PMC8089483 DOI: 10.3389/fcimb.2021.656976] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/19/2021] [Indexed: 12/02/2022] Open
Abstract
The actomyosin contractile ring is a key feature of eukaryotic cytokinesis, conserved across many eukaryotic kingdoms. Recent research into the cell biology of the divergent eukaryotic clade Apicomplexa has revealed a contractile ring structure required for asexual division in the medically relevant genera Toxoplasma and Plasmodium; however, the structure of the contractile ring, known as the basal complex in these parasites, remains poorly characterized and in the absence of a myosin II homolog, it is unclear how the force required of a cytokinetic contractile ring is generated. Here, we review the literature on the basal complex in Apicomplexans, summarizing what is known about its formation and function, and attempt to provide possible answers to this question and suggest new avenues of study by comparing the Apicomplexan basal complex to well-studied, established cytokinetic contractile rings and their mechanisms in organisms such as S. cerevisiae and D. melanogaster. We also compare the basal complex to structures formed during mitochondrial and plastid division and cytokinetic mechanisms of organisms beyond the Opisthokonts, considering Apicomplexan diversity and divergence.
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Affiliation(s)
- Alexander A Morano
- Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, United States.,Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, United States
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
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Koreny L, Zeeshan M, Barylyuk K, Tromer EC, van Hooff JJE, Brady D, Ke H, Chelaghma S, Ferguson DJP, Eme L, Tewari R, Waller RF. Molecular characterization of the conoid complex in Toxoplasma reveals its conservation in all apicomplexans, including Plasmodium species. PLoS Biol 2021; 19:e3001081. [PMID: 33705380 PMCID: PMC7951837 DOI: 10.1371/journal.pbio.3001081] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022] Open
Abstract
The apical complex is the instrument of invasion used by apicomplexan parasites, and the conoid is a conspicuous feature of this apparatus found throughout this phylum. The conoid, however, is believed to be heavily reduced or missing from Plasmodium species and other members of the class Aconoidasida. Relatively few conoid proteins have previously been identified, making it difficult to address how conserved this feature is throughout the phylum, and whether it is genuinely missing from some major groups. Moreover, parasites such as Plasmodium species cycle through 3 invasive forms, and there is the possibility of differential presence of the conoid between these stages. We have applied spatial proteomics and high-resolution microscopy to develop a more complete molecular inventory and understanding of the organisation of conoid-associated proteins in the model apicomplexan Toxoplasma gondii. These data revealed molecular conservation of all conoid substructures throughout Apicomplexa, including Plasmodium, and even in allied Myzozoa such as Chromera and dinoflagellates. We reporter-tagged and observed the expression and location of several conoid complex proteins in the malaria model P. berghei and revealed equivalent structures in all of its zoite forms, as well as evidence of molecular differentiation between blood-stage merozoites and the ookinetes and sporozoites of the mosquito vector. Collectively, we show that the conoid is a conserved apicomplexan element at the heart of the invasion mechanisms of these highly successful and often devastating parasites.
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Affiliation(s)
- Ludek Koreny
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mohammad Zeeshan
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Konstantin Barylyuk
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Eelco C. Tromer
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jolien J. E. van Hooff
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique Evolution, Orsay, France
| | - Declan Brady
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Huiling Ke
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Sara Chelaghma
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - David J. P. Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford, United Kingdom
| | - Laura Eme
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique Evolution, Orsay, France
| | - Rita Tewari
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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Multivalent Interactions Drive the Toxoplasma AC9:AC10:ERK7 Complex To Concentrate ERK7 in the Apical Cap. mBio 2021; 13:e0286421. [PMID: 35130732 PMCID: PMC8822341 DOI: 10.1128/mbio.02864-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Toxoplasma inner membrane complex (IMC) is a specialized organelle that is crucial for the parasite to establish an intracellular lifestyle and ultimately cause disease. The IMC is composed of both membrane and cytoskeletal components, further delineated into the apical cap, body, and basal subcompartments. The apical cap cytoskeleton was recently demonstrated to govern the stability of the apical complex, which controls parasite motility, invasion, and egress. While this role was determined by individually assessing the apical cap proteins AC9, AC10, and the mitogen-activated protein kinase ERK7, how the three proteins collaborate to stabilize the apical complex is unknown. In this study, we use a combination of deletion analyses and yeast two-hybrid experiments to establish that these proteins form an essential complex in the apical cap. We show that AC10 is a foundational component of the AC9:AC10:ERK7 complex and demonstrate that the interactions among them are critical to maintaining the apical complex. Importantly, we identify multiple independent regions of pairwise interaction between each of the three proteins, suggesting that the AC9:AC10:ERK7 complex is organized by multivalent interactions. Together, these data support a model in which multiple interacting domains enable the oligomerization of the AC9:AC10:ERK7 complex and its assembly into the cytoskeletal IMC, which serves as a structural scaffold that concentrates ERK7 kinase activity in the apical cap. IMPORTANCE The phylum Apicomplexa consists of obligate, intracellular parasites, including the causative agents of toxoplasmosis, malaria, and cryptosporidiosis. Hallmarks of these parasites are the IMC and the apical complex, both of which are unique structures that are conserved throughout the phylum and required for parasite survival. The apical cap portion of the IMC has previously been shown to stabilize the apical complex. Here, we expand on those studies to determine the precise protein-protein interactions of the apical cap complex that confer this essential function. We describe the multivalent nature of these interactions and show that the resulting protein oligomers likely tether ERK7 in the apical cap. This study represents the first description of the architecture of the apical cap at a molecular level, expanding our understanding of the unique cell biology that drives Toxoplasma infections.
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Hayward JA, Rajendran E, Zwahlen SM, Faou P, van Dooren GG. Divergent features of the coenzyme Q:cytochrome c oxidoreductase complex in Toxoplasma gondii parasites. PLoS Pathog 2021; 17:e1009211. [PMID: 33524071 PMCID: PMC7877769 DOI: 10.1371/journal.ppat.1009211] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 02/11/2021] [Accepted: 12/03/2020] [Indexed: 11/19/2022] Open
Abstract
The mitochondrion is critical for the survival of apicomplexan parasites. Several major anti-parasitic drugs, such as atovaquone and endochin-like quinolones, act through inhibition of the mitochondrial electron transport chain at the coenzyme Q:cytochrome c oxidoreductase complex (Complex III). Despite being an important drug target, the protein composition of Complex III of apicomplexan parasites has not been elucidated. Here, we undertake a mass spectrometry-based proteomic analysis of Complex III in the apicomplexan Toxoplasma gondii. Along with canonical subunits that are conserved across eukaryotic evolution, we identify several novel or highly divergent Complex III components that are conserved within the apicomplexan lineage. We demonstrate that one such subunit, which we term TgQCR11, is critical for parasite proliferation, mitochondrial oxygen consumption and Complex III activity, and establish that loss of this protein leads to defects in Complex III integrity. We conclude that the protein composition of Complex III in apicomplexans differs from that of the mammalian hosts that these parasites infect.
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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
| | - Soraya M. Zwahlen
- Research School of Biology, Australian National University, Canberra, Australia
| | - Pierre Faou
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Giel G. van Dooren
- Research School of Biology, Australian National University, Canberra, Australia
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28
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Aw YTV, Seidi A, Hayward JA, Lee J, Makota FV, Rug M, van Dooren GG. A key cytosolic iron-sulfur cluster synthesis protein localizes to the mitochondrion of Toxoplasma gondii. Mol Microbiol 2020; 115:968-985. [PMID: 33222310 DOI: 10.1111/mmi.14651] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 11/16/2020] [Accepted: 11/18/2020] [Indexed: 12/21/2022]
Abstract
Iron-sulfur (Fe-S) clusters are prosthetic groups on proteins that function in a range of enzymatic and electron transfer reactions. Fe-S cluster synthesis is essential for the survival of all eukaryotes. Independent Fe-S cluster biosynthesis pathways occur in the mitochondrion, plastid, and cytosolic compartments of eukaryotic cells. Little is known about the cytosolic Fe-S cluster biosynthesis in apicomplexan parasites, the causative agents of diseases such as malaria and toxoplasmosis. NBP35 serves as a key scaffold protein on which cytosolic Fe-S clusters assemble, and has a cytosolic localization in most eukaryotes studied thus far. Unexpectedly, we found that the NBP35 homolog of the apicomplexan Toxoplasma gondii (TgNBP35) localizes to the outer mitochondrial membrane, with mitochondrial targeting mediated by an N-terminal transmembrane domain. We demonstrate that TgNBP35 is critical for parasite proliferation, but that, despite its mitochondrial localization, it is not required for Fe-S cluster synthesis in the mitochondrion. Instead, we establish that TgNBP35 is important for the biogenesis of cytosolic Fe-S proteins. Our data are consistent with TgNBP35 playing a central and specific role in cytosolic Fe-S cluster biosynthesis, and imply that the assembly of cytosolic Fe-S clusters occurs on the cytosolic face of the outer mitochondrial membrane in these parasites.
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Affiliation(s)
- Yi Tong Vincent Aw
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Azadeh Seidi
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Jenni A Hayward
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Jiwon Lee
- Centre for Advanced Microscopy, Australian National University, Canberra, ACT, Australia
| | - F Victor Makota
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Melanie Rug
- Centre for Advanced Microscopy, Australian National University, Canberra, ACT, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Barylyuk K, Koreny L, Ke H, Butterworth S, Crook OM, Lassadi I, Gupta V, Tromer E, Mourier T, Stevens TJ, Breckels LM, Pain A, Lilley KS, Waller RF. A Comprehensive Subcellular Atlas of the Toxoplasma Proteome via hyperLOPIT Provides Spatial Context for Protein Functions. Cell Host Microbe 2020; 28:752-766.e9. [PMID: 33053376 PMCID: PMC7670262 DOI: 10.1016/j.chom.2020.09.011] [Citation(s) in RCA: 160] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/30/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022]
Abstract
Apicomplexan parasites cause major human disease and food insecurity. They owe their considerable success to highly specialized cell compartments and structures. These adaptations drive their recognition, nondestructive penetration, and elaborate reengineering of the host's cells to promote their growth, dissemination, and the countering of host defenses. The evolution of unique apicomplexan cellular compartments is concomitant with vast proteomic novelty. Consequently, half of apicomplexan proteins are unique and uncharacterized. Here, we determine the steady-state subcellular location of thousands of proteins simultaneously within the globally prevalent apicomplexan parasite Toxoplasma gondii. This provides unprecedented comprehensive molecular definition of these unicellular eukaryotes and their specialized compartments, and these data reveal the spatial organizations of protein expression and function, adaptation to hosts, and the underlying evolutionary trajectories of these pathogens.
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Affiliation(s)
| | - Ludek Koreny
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Huiling Ke
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Simon Butterworth
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Oliver M Crook
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB20 0AW, UK; MRC Biostatistics Unit, Cambridge Institute for Public Health, Cambridge CB2 0SR, UK
| | - Imen Lassadi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Vipul Gupta
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Eelco Tromer
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Tobias Mourier
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Tim J Stevens
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Lisa M Breckels
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB20 0AW, UK
| | - Arnab Pain
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia; Global Station for Zoonosis Control, Gi-CoRE, Hokkaido University, Sapporo 060-0808, Japan; Nuffield Division of Clinical Laboratory Sciences (NDCLS), University of Oxford, Oxford OX3 9DU, UK
| | - Kathryn S Lilley
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB20 0AW, UK
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK.
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Dos Santos Pacheco N, Tosetti N, Koreny L, Waller RF, Soldati-Favre D. Evolution, Composition, Assembly, and Function of the Conoid in Apicomplexa. Trends Parasitol 2020; 36:688-704. [DOI: 10.1016/j.pt.2020.05.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 12/14/2022]
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Venugopal K, Chehade S, Werkmeister E, Barois N, Periz J, Lafont F, Tardieux I, Khalife J, Langsley G, Meissner M, Marion S. Rab11A regulates dense granule transport and secretion during Toxoplasma gondii invasion of host cells and parasite replication. PLoS Pathog 2020; 16:e1008106. [PMID: 32463830 PMCID: PMC7255593 DOI: 10.1371/journal.ppat.1008106] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/10/2020] [Indexed: 12/31/2022] Open
Abstract
Toxoplasma gondii possesses an armada of secreted virulent factors that enable parasite invasion and survival into host cells. These factors are contained in specific secretory organelles, the rhoptries, micronemes and dense granules that release their content upon host cell recognition. Dense granules are secreted in a constitutive manner during parasite replication and play a crucial role in modulating host metabolic and immune responses. While the molecular mechanisms triggering rhoptry and microneme release upon host cell adhesion have been well studied, constitutive secretion remains a poorly explored aspect of T. gondii vesicular trafficking. Here, we investigated the role of the small GTPase Rab11A, a known regulator of exocytosis in eukaryotic cells. Our data revealed an essential role of Rab11A in promoting the cytoskeleton driven transport of dense granules and the release of their content into the vacuolar space. Rab11A also regulates transmembrane protein trafficking and localization during parasite replication, indicating a broader role of Rab11A in cargo exocytosis at the plasma membrane. Moreover, we found that Rab11A also regulates extracellular parasite motility and adhesion to host cells. In line with these findings, MIC2 secretion was altered in Rab11A-defective parasites, which also exhibited severe morphological defects. Strikingly, by live imaging we observed a polarized accumulation of Rab11A-positive vesicles and dense granules at the apical pole of extracellular motile and invading parasites suggesting that apically polarized Rab11A-dependent delivery of cargo regulates early secretory events during parasite entry into host cells. Toxoplasma gondii (T. gondii) is a highly prevalent parasite infecting a wide range of animals as well as humans. T. gondii secretes numerous virulent factors contained in specific organelles, termed the rhoptries, micronemes and dense granules. These factors are released upon host cell recognition and enable parasite invasion and subsequent development into an intracellular vacuole. In particular, dense granules contain critical effectors that modulate intrinsic defenses of infected host cells ensuring parasite survival and dissemination. The mechanisms regulating dense granule secretion have not been elucidated. In this study, we unraveled a novel role for the T. gondii GTPase Rab11A in promoting dense granule transport along the parasite cytoskeleton and their content release into the vacuolar space during parasite replication. We also found that T. gondii Rab11A regulates extracellular parasite motility and adhesion to host cells suggesting a broader role in distinct secretory pathways essential for parasite virulence.
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Affiliation(s)
- Kannan Venugopal
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Sylia Chehade
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Elisabeth Werkmeister
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Nicolas Barois
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Javier Periz
- Department of Veterinary Sciences, Experimental Parasitology, Ludwig-Maximilians-Universität, Munich, Germany
| | - Frank Lafont
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Isabelle Tardieux
- Institute for Advanced Biosciences (IAB), Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Jamal Khalife
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
| | - Gordon Langsley
- Laboratoire de Biologie Comparative des Apicomplexes, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, France, INSERM U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Markus Meissner
- Department of Veterinary Sciences, Experimental Parasitology, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sabrina Marion
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Center for Infection and Immunity of Lille, Lille, France
- * E-mail:
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Ancient MAPK ERK7 is regulated by an unusual inhibitory scaffold required for Toxoplasma apical complex biogenesis. Proc Natl Acad Sci U S A 2020; 117:12164-12173. [PMID: 32409604 PMCID: PMC7275706 DOI: 10.1073/pnas.1921245117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Apicomplexan parasites include organisms that cause widespread and devastating human diseases such as malaria, cryptosporidiosis, and toxoplasmosis. These parasites are named for a structure, called the “apical complex,” that organizes their invasion and secretory machinery. We found that two proteins, apical cap protein 9 (AC9) and an enzyme called ERK7, work together to facilitate apical complex assembly. Intriguingly, ERK7 is an ancient molecule that is found throughout Eukaryota, though its regulation and function are poorly understood. AC9 is a scaffold that concentrates ERK7 at the base of the developing apical complex. In addition, AC9 binding likely confers substrate selectivity upon ERK7. This simple competitive regulatory model may be a powerful but largely overlooked mechanism throughout biology. Apicomplexan parasites use a specialized cilium structure called the apical complex to organize their secretory organelles and invasion machinery. The apical complex is integrally associated with both the parasite plasma membrane and an intermediate filament cytoskeleton called the inner-membrane complex (IMC). While the apical complex is essential to the parasitic lifestyle, little is known about the regulation of apical complex biogenesis. Here, we identify AC9 (apical cap protein 9), a largely intrinsically disordered component of the Toxoplasma gondii IMC, as essential for apical complex development, and therefore for host cell invasion and egress. Parasites lacking AC9 fail to successfully assemble the tubulin-rich core of their apical complex, called the conoid. We use proximity biotinylation to identify the AC9 interaction network, which includes the kinase extracellular signal-regulated kinase 7 (ERK7). Like AC9, ERK7 is required for apical complex biogenesis. We demonstrate that AC9 directly binds ERK7 through a conserved C-terminal motif and that this interaction is essential for ERK7 localization and function at the apical cap. The crystal structure of the ERK7–AC9 complex reveals that AC9 is not only a scaffold but also inhibits ERK7 through an unusual set of contacts that displaces nucleotide from the kinase active site. ERK7 is an ancient and autoactivating member of the mitogen-activated kinase (MAPK) family and its regulation is poorly understood in all organisms. We propose that AC9 dually regulates ERK7 by scaffolding and concentrating it at its site of action while maintaining it in an “off” state until the specific binding of a true substrate.
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Tosetti N, Dos Santos Pacheco N, Bertiaux E, Maco B, Bournonville L, Hamel V, Guichard P, Soldati-Favre D. Essential function of the alveolin network in the subpellicular microtubules and conoid assembly in Toxoplasma gondii. eLife 2020; 9:56635. [PMID: 32379047 PMCID: PMC7228768 DOI: 10.7554/elife.56635] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/06/2020] [Indexed: 12/14/2022] Open
Abstract
The coccidian subgroup of Apicomplexa possesses an apical complex harboring a conoid, made of unique tubulin polymer fibers. This enigmatic organelle extrudes in extracellular invasive parasites and is associated to the apical polar ring (APR). The APR serves as microtubule-organizing center for the 22 subpellicular microtubules (SPMTs) that are linked to a patchwork of flattened vesicles, via an intricate network composed of alveolins. Here, we capitalize on ultrastructure expansion microscopy (U-ExM) to localize the Toxoplasma gondii Apical Cap protein 9 (AC9) and its partner AC10, identified by BioID, to the alveolin network and intercalated between the SPMTs. Parasites conditionally depleted in AC9 or AC10 replicate normally but are defective in microneme secretion and fail to invade and egress from infected cells. Electron microscopy revealed that the mature parasite mutants are conoidless, while U-ExM highlighted the disorganization of the SPMTs which likely results in the catastrophic loss of APR and conoid.
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Affiliation(s)
- Nicolò Tosetti
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nicolas Dos Santos Pacheco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Eloïse Bertiaux
- Department of Cell Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Lorène Bournonville
- Department of Cell Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Virginie Hamel
- Department of Cell Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Paul Guichard
- Department of Cell Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Predatory colponemids are the sister group to all other alveolates. Mol Phylogenet Evol 2020; 149:106839. [PMID: 32325195 DOI: 10.1016/j.ympev.2020.106839] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 11/20/2022]
Abstract
Alveolates are a major supergroup of eukaryotes encompassing more than ten thousand free-living and parasitic species, including medically, ecologically, and economically important apicomplexans, dinoflagellates, and ciliates. These three groups are among the most widespread eukaryotes on Earth, and their environmental success can be linked to unique innovations that emerged early in each group. Understanding the emergence of these well-studied and diverse groups and their innovations has relied heavily on the discovery and characterization of early-branching relatives, which allow ancestral states to be inferred with much greater confidence. Here we report the phylogenomic analyses of 313 eukaryote protein-coding genes from transcriptomes of three members of one such group, the colponemids (Colponemidia), which support their monophyly and position as the sister lineage to all other known alveolates. Colponemid-related sequences from environmental surveys and our microscopical observations show that colponemids are not common in nature, but they are diverse and widespread in freshwater habitats around the world. Studied colponemids possess two types of extrusive organelles (trichocysts or toxicysts) for active hunting of other unicellular eukaryotes and potentially play an important role in microbial food webs. Colponemids have generally plesiomorphic morphology and illustrate the ancestral state of Alveolata. We further discuss their importance in understanding the evolution of alveolates and the origin of myzocytosis and plastids.
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Division and Adaptation to Host Environment of Apicomplexan Parasites Depend on Apicoplast Lipid Metabolic Plasticity and Host Organelle Remodeling. Cell Rep 2020; 30:3778-3792.e9. [DOI: 10.1016/j.celrep.2020.02.072] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 11/12/2019] [Accepted: 02/19/2020] [Indexed: 11/20/2022] Open
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Tjhin ET, Hayward JA, McFadden GI, van Dooren GG. Characterization of the apicoplast-localized enzyme TgUroD in Toxoplasma gondii reveals a key role of the apicoplast in heme biosynthesis. J Biol Chem 2020; 295:1539-1550. [PMID: 31914409 PMCID: PMC7008375 DOI: 10.1074/jbc.ra119.011605] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/21/2019] [Indexed: 12/29/2022] Open
Abstract
Apicomplexan parasites such as Toxoplasma gondii possess an unusual heme biosynthesis pathway whose enzymes localize to the mitochondrion, cytosol, or apicoplast, a nonphotosynthetic plastid present in most apicomplexans. To characterize the involvement of the apicoplast in the T. gondii heme biosynthesis pathway, we investigated the role of the apicoplast-localized enzyme uroporphyrinogen III decarboxylase (TgUroD). We found that TgUroD knockdown impaired parasite proliferation, decreased free heme levels in the parasite, and decreased the abundance of heme-containing c-type cytochrome proteins in the parasite mitochondrion. We validated the effects of heme loss on mitochondrial cytochromes by knocking down cytochrome c/c1 heme lyase 1 (TgCCHL1), a mitochondrial enzyme that catalyzes the covalent attachment of heme to c-type cytochromes. TgCCHL1 depletion reduced parasite proliferation and decreased the abundance of c-type cytochromes. We further sought to characterize the overall importance of TgUroD and TgCCHL1 for both mitochondrial and general parasite metabolism. TgUroD depletion decreased cellular ATP levels, mitochondrial oxygen consumption, and extracellular acidification rates. By contrast, depletion of TgCCHL1 neither diminished ATP levels in the parasite nor impaired extracellular acidification rate, but resulted in specific defects in mitochondrial oxygen consumption. Together, our results indicate that the apicoplast has a key role in heme biology in T. gondii and is important for both mitochondrial and general parasite metabolism. Our study highlights the importance of heme and its synthesis in these parasites.
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Affiliation(s)
- Edwin T Tjhin
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Jenni A Hayward
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Geoffrey I McFadden
- School of BioSciences University of Melbourne, Parkville, VIC 3010, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
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37
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Hicks JL, Lassadi I, Carpenter EF, Eno M, Vardakis A, Waller RF, Howe CJ, Nisbet RER. An essential pentatricopeptide repeat protein in the apicomplexan remnant chloroplast. Cell Microbiol 2019; 21:e13108. [PMID: 31454137 PMCID: PMC6899631 DOI: 10.1111/cmi.13108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/12/2019] [Accepted: 08/20/2019] [Indexed: 02/06/2023]
Abstract
The malaria parasite Plasmodium and other apicomplexans such as Toxoplasma evolved from photosynthetic organisms and contain an essential, remnant plastid termed the apicoplast. Transcription of the apicoplast genome is polycistronic with extensive RNA processing. Yet little is known about the mechanism of apicoplast RNA processing. In plants, chloroplast RNA processing is controlled by multiple pentatricopeptide repeat (PPR) proteins. Here, we identify the single apicoplast PPR protein, PPR1. We show that the protein is essential and that it binds to RNA motifs corresponding with previously characterized processing sites. Additionally, PPR1 shields RNA transcripts from ribonuclease degradation. This is the first characterization of a PPR protein from a nonphotosynthetic plastid.
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Affiliation(s)
- Joanna L. Hicks
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Present address:
Faculty of ScienceWaikato UniversityHamiltonNew Zealand
| | - Imen Lassadi
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Madeleine Eno
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Ross F. Waller
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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38
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Lentini G, Dubois DJ, Maco B, Soldati-Favre D, Frénal K. The roles of Centrin 2 and Dynein Light Chain 8a in apical secretory organelles discharge of Toxoplasma gondii. Traffic 2019; 20:583-600. [PMID: 31206964 DOI: 10.1111/tra.12673] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 06/08/2019] [Accepted: 06/12/2019] [Indexed: 12/31/2022]
Abstract
To efficiently enter host cells, apicomplexan parasites such as Toxoplasma gondii rely on an apical complex composed of tubulin-based structures as well as two sets of secretory organelles named micronemes and rhoptries. The trafficking and docking of these organelles to the apical pole of the parasite is crucial for the discharge of their contents. Here, we describe two proteins typically associated with microtubules, Centrin 2 (CEN2) and Dynein Light Chain 8a (DLC8a), that are required for efficient host cell invasion. CEN2 localizes to four different compartments, and remarkably, conditional depletion of the protein occurs in stepwise manner, sequentially depleting the protein pools from each location. This phenomenon allowed us to discern the essential function of the apical pool of CEN2 for microneme secretion, motility, invasion and egress. DLC8a localizes to the conoid, and its depletion also perturbs microneme exocytosis in addition to the apical docking of the rhoptry organelles, causing a severe defect in host cell invasion. Phenotypic characterization of CEN2 and DLC8a indicates that while both proteins participate in microneme secretion, they likely act at different steps along the cascade of events leading to organelle exocytosis.
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Affiliation(s)
- Gaëlle Lentini
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - David J Dubois
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - Karine Frénal
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland.,Microbiologie Fondamentale et Pathogénicité, University of Bordeaux, CNRS UMR 5234, Bordeaux Cedex, France
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39
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The dense granule protein 8 (GRA8) is a component of the sub-pellicular cytoskeleton in Toxoplasma gondii. Parasitol Res 2019; 118:1899-1918. [PMID: 30949853 DOI: 10.1007/s00436-019-06298-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/18/2019] [Indexed: 12/24/2022]
Abstract
After host cell invasion, Toxoplasma secretes a variety of dense granule proteins (GRA proteins) from its secretory dense granules, which are involved in the biogenesis of the parasitophorous vacuole (PV). TgGRA8I is predicted to contain proline-rich domains, which are structural features of some cytoskeleton-related proteins. In agreement with this observation, previous proteomic analyses revealed the presence of TgGRA8I in the Toxoplasma sub-pellicular cytoskeleton. In the present study, we show (1) by docking analyses that TgGRA8I may interact with both Toxoplasma β-tubulin and actin; (2) by immunoelectron microscopy, proteomic, biochemical, and cellular approaches that TgGRA8I associates with sub-pellicular microtubules and actin at the parasite sub-pellicular cytoskeleton; (3) that type I parasites (RH strain) lacking the GRA8 gene (RHΔku80Δgra8) exhibit loss of conoid extrusion, diminished cell infection, and egress capabilities, and that these motility impairments were likely due to important alterations in their sub-pellicular cytoskeleton, in particular their sub-pellicular microtubules and meshwork. Parasites lacking the GRA4 gene (RHΔku80Δgra4) did not show modifications in the organization of the sub-pellicular cytoskeleton. Collectively, these results demonstrated that TgGRA8I is a dense granule protein that, besides its role in the formation of the PV, contributes to the organization of the parasite sub-pellicular cytoskeleton and motility. This is the first proline-rich protein described in the Toxoplasma cytoskeleton, which is a key organelle for both the parasite motility and the invasion process. Knowledge about the function of cytoskeleton components in Toxoplasma is fundamental to understand the motility process and the host cell invasion mechanism. Refining this knowledge should lead to the design of novel pharmacological strategies for the treatment against toxoplasmosis.
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40
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Dubois DJ, Soldati-Favre D. Biogenesis and secretion of micronemes in Toxoplasma gondii. Cell Microbiol 2019; 21:e13018. [PMID: 30791192 DOI: 10.1111/cmi.13018] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/11/2019] [Accepted: 02/17/2019] [Indexed: 12/20/2022]
Abstract
One of the hallmarks of the parasitic phylum of Apicomplexa is the presence of highly specialised, apical secretory organelles, called the micronemes and rhoptries that play critical roles in ensuring survival and dissemination. Upon exocytosis, the micronemes release adhesin complexes, perforins, and proteases that are crucially implicated in egress from infected cells, gliding motility, migration across biological barriers, and host cell invasion. Recent studies on Toxoplasma gondii and Plasmodium species have shed more light on the signalling events and the machinery that trigger microneme secretion. Intracellular cyclic nucleotides, calcium level, and phosphatidic acid act as key mediators of microneme exocytosis, and several downstream effectors have been identified. Here, we review the key steps of microneme biogenesis and exocytosis, summarising the still fractal knowledge at the molecular level regarding the fusion event with the parasite plasma membrane.
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Affiliation(s)
- David J Dubois
- Department of Microbiology and Molecular Medicine, University of Geneva CMU, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva CMU, Geneva, Switzerland
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41
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Katris NJ, Ke H, McFadden GI, van Dooren GG, Waller RF. Calcium negatively regulates secretion from dense granules in Toxoplasma gondii. Cell Microbiol 2019; 21:e13011. [PMID: 30673152 PMCID: PMC6563121 DOI: 10.1111/cmi.13011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/05/2018] [Accepted: 01/17/2019] [Indexed: 12/23/2022]
Abstract
Apicomplexan parasites including Toxoplasma gondii and Plasmodium spp. manufacture a complex arsenal of secreted proteins used to interact with and manipulate their host environment. These proteins are organised into three principle exocytotic compartment types according to their functions: micronemes for extracellular attachment and motility, rhoptries for host cell penetration, and dense granules for subsequent manipulation of the host intracellular environment. The order and timing of these events during the parasite's invasion cycle dictates when exocytosis from each compartment occurs. Tight control of compartment secretion is, therefore, an integral part of apicomplexan biology. Control of microneme exocytosis is best understood, where cytosolic intermediate molecular messengers cGMP and Ca2+ act as positive signals. The mechanisms for controlling secretion from rhoptries and dense granules, however, are virtually unknown. Here, we present evidence that dense granule exocytosis is negatively regulated by cytosolic Ca2+, and we show that this Ca2+‐mediated response is contingent on the function of calcium‐dependent protein kinases TgCDPK1 and TgCDPK3. Reciprocal control of micronemes and dense granules provides an elegant solution to the mutually exclusive functions of these exocytotic compartments in parasite invasion cycles and further demonstrates the central role that Ca2+ signalling plays in the invasion biology of apicomplexan parasites.
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Affiliation(s)
- Nicholas J Katris
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,School of Biosciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Huiling Ke
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Geoffrey I McFadden
- School of Biosciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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42
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Lehane AM, Dennis ASM, Bray KO, Li D, Rajendran E, McCoy JM, McArthur HM, Winterberg M, Rahimi F, Tonkin CJ, Kirk K, van Dooren GG. Characterization of the ATP4 ion pump in Toxoplasma gondii. J Biol Chem 2019; 294:5720-5734. [PMID: 30723156 DOI: 10.1074/jbc.ra118.006706] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/31/2019] [Indexed: 12/22/2022] Open
Abstract
The Plasmodium falciparum ATPase PfATP4 is the target of a diverse range of antimalarial compounds, including the clinical drug candidate cipargamin. PfATP4 was originally annotated as a Ca2+ transporter, but recent evidence suggests that it is a Na+ efflux pump, extruding Na+ in exchange for H+ Here we demonstrate that ATP4 proteins belong to a clade of P-type ATPases that are restricted to apicomplexans and their closest relatives. We employed a variety of genetic and physiological approaches to investigate the ATP4 protein of the apicomplexan Toxoplasma gondii, TgATP4. We show that TgATP4 is a plasma membrane protein. Knockdown of TgATP4 had no effect on resting pH or Ca2+ but rendered parasites unable to regulate their cytosolic Na+ concentration ([Na+]cyt). PfATP4 inhibitors caused an increase in [Na+]cyt and a cytosolic alkalinization in WT but not TgATP4 knockdown parasites. Parasites in which TgATP4 was knocked down or disrupted exhibited a growth defect, attributable to reduced viability of extracellular parasites. Parasites in which TgATP4 had been disrupted showed reduced virulence in mice. These results provide evidence for ATP4 proteins playing a key conserved role in Na+ regulation in apicomplexan parasites.
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Affiliation(s)
- Adele M Lehane
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
| | - Adelaide S M Dennis
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Katherine O Bray
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Dongdi Li
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Esther Rajendran
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - James M McCoy
- the Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC 3052, Australia, and.,the Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hillary M McArthur
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Markus Winterberg
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Farid Rahimi
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Christopher J Tonkin
- the Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC 3052, Australia, and.,the Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kiaran Kirk
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
| | - Giel G van Dooren
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
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43
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Pivovarova Y, Liu J, Lesigang J, Koldyka O, Rauschmeier R, Hu K, Dong G. Structure of a Novel Dimeric SET Domain Methyltransferase that Regulates Cell Motility. J Mol Biol 2018; 430:4209-4229. [PMID: 30148980 PMCID: PMC7141177 DOI: 10.1016/j.jmb.2018.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 11/21/2022]
Abstract
Lysine methyltransferases (KMTs) were initially associated with transcriptional control through their methylation of histones and other nuclear proteins, but have since been found to regulate many other cellular activities. The apical complex lysine (K) methyltransferase (AKMT) of the human parasite Toxoplasma gondii was recently shown to play a critical role in regulating cellular motility. Here we report a 2.1-Å resolution crystal structure of the conserved and functional C-terminal portion (aa289-709) of T. gondii AKMT. AKMT dimerizes via a unique intermolecular interface mediated by the C-terminal tetratricopeptide repeat-like domain together with a specific zinc-binding motif that is absent from all other KMTs. Disruption of AKMT dimerization impaired both its enzyme activity and parasite egress from infected host cells in vivo. Structural comparisons reveal that AKMT is related to the KMTs in the SMYD family, with, however, a number of distinct structural features in addition to the unusual dimerization interface. These features are conserved among the apicomplexan parasites and their free-living relatives, but not found in any known KMTs in animals. AKMT therefore is the founding member of a new subclass of KMT that has important implications for the evolution of the apicomplexans.
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Affiliation(s)
- Yulia Pivovarova
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Johannes Lesigang
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | | | - Rene Rauschmeier
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
| | - Gang Dong
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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44
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Uboldi AD, Wilde ML, McRae EA, Stewart RJ, Dagley LF, Yang L, Katris NJ, Hapuarachchi SV, Coffey MJ, Lehane AM, Botte CY, Waller RF, Webb AI, McConville MJ, Tonkin CJ. Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii. PLoS Biol 2018; 16:e2005642. [PMID: 30208022 PMCID: PMC6152992 DOI: 10.1371/journal.pbio.2005642] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 09/24/2018] [Accepted: 08/20/2018] [Indexed: 11/18/2022] Open
Abstract
The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating stages and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is complete to allow for replication to begin is not understood. Here, we show that the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1). Upon genetic depletion of PKAc1 we show that newly invaded parasites exit host cells shortly thereafter, in a perforin-like protein 1 (PLP-1)-dependent fashion. Furthermore, we demonstrate that loss of PKAc1 prevents rapid down-regulation of cytosolic [Ca2+] levels shortly after invasion. We also provide evidence that loss of PKAc1 sensitises parasites to cyclic GMP (cGMP)-induced Ca2+ signalling, thus demonstrating a functional link between cAMP and these other signalling modalities. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity. Central to pathogenesis and infectivity of Toxoplasma and related parasites is their ability to move through tissue, invade host cells, and establish a replicative niche. Ca2+-dependent signalling pathways are important for activating motility, host cell invasion, and egress, yet how this signalling is turned off after invasion is unclear. Here, we show that a cAMP-dependent protein kinase A (PKA) is essential for rapid suppression of Ca2+ signalling upon completion of host cell invasion. Parasites lacking this kinase rapidly invoke an egress program to re-exit host cells, thus preventing the establishment of a stable infection. This finding therefore highlights the first factor required for Toxoplasma (and any related apicomplexan parasite) to switch from invasive to the replicative forms.
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Affiliation(s)
- Alessandro D. Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Mary-Louise Wilde
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Emi A. McRae
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Rebecca J. Stewart
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Laura F. Dagley
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Luning Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- School of Medicine, Tsinghua University, Beijing, China
| | - Nicholas J. Katris
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | | | - Michael J. Coffey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Adele M. Lehane
- Research School of Biology, The Australian National University, A.C.T., Australia
| | - Cyrille Y. Botte
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Andrew I. Webb
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- * E-mail:
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45
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Seidi A, Muellner-Wong LS, Rajendran E, Tjhin ET, Dagley LF, Aw VYT, Faou P, Webb AI, Tonkin CJ, van Dooren GG. Elucidating the mitochondrial proteome of Toxoplasma gondii reveals the presence of a divergent cytochrome c oxidase. eLife 2018; 7:e38131. [PMID: 30204084 PMCID: PMC6156079 DOI: 10.7554/elife.38131] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 09/09/2018] [Indexed: 12/17/2022] Open
Abstract
The mitochondrion of apicomplexan parasites is critical for parasite survival, although the full complement of proteins that localize to this organelle has not been defined. Here we undertake two independent approaches to elucidate the mitochondrial proteome of the apicomplexan Toxoplasma gondii. We identify approximately 400 mitochondrial proteins, many of which lack homologs in the animals that these parasites infect, and most of which are important for parasite growth. We demonstrate that one such protein, termed TgApiCox25, is an important component of the parasite cytochrome c oxidase (COX) complex. We identify numerous other apicomplexan-specific components of COX, and conclude that apicomplexan COX, and apicomplexan mitochondria more generally, differ substantially in their protein composition from the hosts they infect. Our study highlights the diversity that exists in mitochondrial proteomes across the eukaryotic domain of life, and provides a foundation for defining unique aspects of mitochondrial biology in an important phylum of parasites.
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Affiliation(s)
- Azadeh Seidi
- Research School of BiologyAustralian National UniversityCanberraAustralia
| | | | - Esther Rajendran
- Research School of BiologyAustralian National UniversityCanberraAustralia
| | - Edwin T Tjhin
- Research School of BiologyAustralian National UniversityCanberraAustralia
| | - Laura F Dagley
- The Walter and Eliza Hall Institute of Medical ResearchVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneVictoriaAustralia
| | - Vincent YT Aw
- Research School of BiologyAustralian National UniversityCanberraAustralia
| | - Pierre Faou
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityVictoriaAustralia
| | - Andrew I Webb
- The Walter and Eliza Hall Institute of Medical ResearchVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneVictoriaAustralia
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical ResearchVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneVictoriaAustralia
| | - Giel G van Dooren
- Research School of BiologyAustralian National UniversityCanberraAustralia
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46
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Hortua Triana MA, Márquez-Nogueras KM, Vella SA, Moreno SNJ. Calcium signaling and the lytic cycle of the Apicomplexan parasite Toxoplasma gondii. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1846-1856. [PMID: 30992126 DOI: 10.1016/j.bbamcr.2018.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 01/24/2023]
Abstract
Toxoplasma gondii has a complex life cycle involving different hosts and is dependent on fast responses, as the parasite reacts to changing environmental conditions. T. gondii causes disease by lysing the host cells that it infects and it does this by reiterating its lytic cycle, which consists of host cell invasion, replication inside the host cell, and egress causing host cell lysis. Calcium ion (Ca2+) signaling triggers activation of molecules involved in the stimulation and enhancement of each step of the parasite lytic cycle. Ca2+ signaling is essential for the cellular and developmental changes that support T. gondii parasitism. The characterization of the molecular players and pathways directly activated by Ca2+ signaling in Toxoplasma is sketchy and incomplete. The evolutionary distance between Toxoplasma and other eukaryotic model systems makes the comparison sometimes not informative. The advent of new genomic information and new genetic tools applicable for studying Toxoplasma biology is rapidly changing this scenario. The Toxoplasma genome reveals the presence of many genes potentially involved in Ca2+ signaling, even though the role of most of them is not known. The use of Genetically Encoded Calcium Indicators (GECIs) has allowed studies on the role of novel calcium-related proteins on egress, an essential step for the virulence and dissemination of Toxoplasma. In addition, the discovery of new Ca2+ players is generating novel targets for drugs, vaccines, and diagnostic tools and a better understanding of the biology of these parasites.
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Affiliation(s)
| | | | - Stephen A Vella
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Silvia N J Moreno
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA; Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA.
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47
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Preisner H, Habicht J, Garg SG, Gould SB. Intermediate filament protein evolution and protists. Cytoskeleton (Hoboken) 2018; 75:231-243. [PMID: 29573204 DOI: 10.1002/cm.21443] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 01/20/2023]
Abstract
Metazoans evolved from a single protist lineage. While all eukaryotes share a conserved actin and tubulin-based cytoskeleton, it is commonly perceived that intermediate filaments (IFs), including lamin, vimentin or keratin among many others, are restricted to metazoans. Actin and tubulin proteins are conserved enough to be detectable across all eukaryotic genomes using standard phylogenetic methods, but IF proteins, in contrast, are notoriously difficult to identify by such means. Since the 1950s, dozens of cytoskeletal proteins in protists have been identified that seemingly do not belong to any of the IF families described for metazoans, yet, from a structural and functional perspective fit criteria that define metazoan IF proteins. Here, we briefly review IF protein discovery in metazoans and the implications this had for the definition of this protein family. We argue that the many cytoskeletal and filament-forming proteins of protists should be incorporated into a more comprehensive picture of IF evolution by aligning it with the recent identification of lamins across the phylogenetic diversity of eukaryotic supergroups. This then brings forth the question of how the diversity of IF proteins has unfolded. The evolution of IF proteins likely represents an example of convergent evolution, which, in combination with the speed with which these cytoskeletal proteins are evolving, generated their current diversity. IF proteins did not first emerge in metazoa, but in protists. Only the emergence of cytosolic IF proteins that appear to stem from a nuclear lamin is unique to animals and coincided with the emergence of true animal multicellularity.
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Affiliation(s)
- Harald Preisner
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jörn Habicht
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
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48
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A conserved ankyrin repeat-containing protein regulates conoid stability, motility and cell invasion in Toxoplasma gondii. Nat Commun 2017; 8:2236. [PMID: 29269729 PMCID: PMC5740107 DOI: 10.1038/s41467-017-02341-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/22/2017] [Indexed: 11/08/2022] Open
Abstract
Apicomplexan parasites are typified by an apical complex that contains a unique microtubule-organizing center (MTOC) that organizes the cytoskeleton. In apicomplexan parasites such as Toxoplasma gondii, the apical complex includes a spiral cap of tubulin-rich fibers called the conoid. Although described ultrastructurally, the composition and functions of the conoid are largely unknown. Here, we localize 11 previously undescribed apical proteins in T. gondii and identify an essential component named conoid protein hub 1 (CPH1), which is conserved in apicomplexan parasites. CPH1 contains ankyrin repeats that are required for structural integrity of the conoid, parasite motility, and host cell invasion. Proximity labeling and protein interaction network analysis reveal that CPH1 functions as a hub linking key motor and structural proteins that contain intrinsically disordered regions and coiled coil domains. Our findings highlight the importance of essential protein hubs in controlling biological networks of MTOCs in early-branching protozoan parasites. Apicomplexan parasites such as Toxoplasma gondii possess a tubulin-rich structure called the conoid. Here, Long et al. identify a conoid protein that interacts with motor and structural proteins and is required for structural integrity of the conoid, parasite motility, and host cell invasion.
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Saini E, Zeeshan M, Brady D, Pandey R, Kaiser G, Koreny L, Kumar P, Thakur V, Tatiya S, Katris NJ, Limenitakis RS, Kaur I, Green JL, Bottrill AR, Guttery DS, Waller RF, Heussler V, Holder AA, Mohmmed A, Malhotra P, Tewari R. Photosensitized INA-Labelled protein 1 (PhIL1) is novel component of the inner membrane complex and is required for Plasmodium parasite development. Sci Rep 2017; 7:15577. [PMID: 29138437 PMCID: PMC5686188 DOI: 10.1038/s41598-017-15781-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
Plasmodium parasites, the causative agents of malaria, possess a distinctive membranous structure of flattened alveolar vesicles supported by a proteinaceous network, and referred to as the inner membrane complex (IMC). The IMC has a role in actomyosin-mediated motility and host cell invasion. Here, we examine the location, protein interactome and function of PhIL1, an IMC-associated protein on the motile and invasive stages of both human and rodent parasites. We show that PhIL1 is located in the IMC in all three invasive (merozoite, ookinete-, and sporozoite) stages of development, as well as in the male gametocyte and locates both at the apical and basal ends of ookinete and sporozoite stages. Proteins interacting with PhIL1 were identified, showing that PhIL1 was bound to only some proteins present in the glideosome motor complex (GAP50, GAPM1–3) of both P. falciparum and P. berghei. Analysis of PhIL1 function using gene targeting approaches indicated that the protein is required for both asexual and sexual stages of development. In conclusion, we show that PhIL1 is required for development of all zoite stages of Plasmodium and it is part of a novel protein complex with an overall composition overlapping with but different to that of the glideosome.
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Affiliation(s)
- Ekta Saini
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Mohammad Zeeshan
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Declan Brady
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK
| | - Rajan Pandey
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Gesine Kaiser
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | - Ludek Koreny
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Pradeep Kumar
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Shreyansh Tatiya
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Nicholas J Katris
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | | | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | | | - Andrew R Bottrill
- Protein and Nucleic Acid Chemistry Laboratory, University of Leicester, Leicester, LE2 7LX, UK
| | - David S Guttery
- Department of Cancer studies, University of Leicester, Leicester, LE2 7LX, UK
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Volker Heussler
- Institute of Cell Biology, University of Bern, Bern, 3012, Switzerland
| | | | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Pawan Malhotra
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
| | - Rita Tewari
- School of Life Sciences, University of Nottingham, Nottingham, NG72UH, UK.
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