51
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Alday PH, Doggett JS. Drugs in development for toxoplasmosis: advances, challenges, and current status. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:273-293. [PMID: 28182168 PMCID: PMC5279849 DOI: 10.2147/dddt.s60973] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Toxoplasma gondii causes fatal and debilitating brain and eye diseases. Medicines that are currently used to treat toxoplasmosis commonly have toxic side effects and require prolonged courses that range from weeks to more than a year. The need for long treatment durations and the risk of relapsing disease are in part due to the lack of efficacy against T. gondii tissue cysts. The challenges for developing a more effective treatment for toxoplasmosis include decreasing toxicity, achieving therapeutic concentrations in the brain and eye, shortening duration, eliminating tissue cysts from the host, safety in pregnancy, and creating a formulation that is inexpensive and practical for use in resource-poor areas of the world. Over the last decade, significant progress has been made in identifying and developing new compounds for the treatment of toxoplasmosis. Unlike clinically used medicines that were repurposed for toxoplasmosis, these compounds have been optimized for efficacy against toxoplasmosis during preclinical development. Medicines with enhanced efficacy as well as features that address the unique aspects of toxoplasmosis have the potential to greatly improve toxoplasmosis therapy. This review discusses the facets of toxoplasmosis that are pertinent to drug design and the advances, challenges, and current status of preclinical drug research for toxoplasmosis.
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Affiliation(s)
- P Holland Alday
- Division of Infectious Diseases, Oregon Health & Science University
| | - Joseph Stone Doggett
- Division of Infectious Diseases, Oregon Health & Science University; Portland Veterans Affairs Medical Center, Portland, OR, USA
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52
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A Critical Role for Toxoplasma gondii Vacuolar Protein Sorting VPS9 in Secretory Organelle Biogenesis and Host Infection. Sci Rep 2016; 6:38842. [PMID: 27966671 PMCID: PMC5155228 DOI: 10.1038/srep38842] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/15/2016] [Indexed: 12/18/2022] Open
Abstract
Accurate sorting of proteins to the three types of parasite-specific secretory organelles namely rhoptry, microneme and dense granule in Toxoplasma gondii is crucial for successful host cell invasion by this obligate intracellular parasite. Despite its tiny body architecture and limited trafficking machinery, T. gondii relies heavily on transport of vesicles containing proteins, lipids and important virulence-like factors that are delivered to these secretory organelles. However, our understanding on how trafficking of vesicles operates in the parasite is still limited. Here, we show that the T. gondii vacuolar protein sorting 9 (TgVps9), has guanine nucleotide exchange factor (GEF) activity towards Rab5a and is crucial for sorting of proteins destined to secretory organelles. Our results illuminate features of TgVps9 protein as a key trafficking facilitator that regulates protein maturation, secretory organelle formation and secretion, thereby ensuring a primary role in host infection by T. gondii.
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53
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Caldas LA, Soares LL, Henrique Seabra S, Attias M, de Souza W. Monitoring of dynamin during the Toxoplasma gondii cell cycle. Pathog Dis 2016; 74:ftw108. [PMID: 27811048 DOI: 10.1093/femspd/ftw108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/29/2016] [Accepted: 10/29/2016] [Indexed: 11/13/2022] Open
Abstract
The obligate intracellular protozoan parasite Toxoplasma gondii actively invades virtually all warm-blooded nucleated cells. This process results in a non-fusogenic vacuole, inside which the parasites replicate continuously until egress signaling is triggered. In this work, we investigated the role of the large GTPase dynamin in the interaction of T. gondii with the host cell by using laser and electron microscopy during three key stages: invasion, development and egress. The detection of dynamin during invasion indicates the occurrence of endocytosis, while T. gondii egress appeared to be independent of dynamin participation. However, the presence of dynamin during T. gondii development suggests that this molecule plays undescribed roles in the tachyzoite's cell cycle.
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Affiliation(s)
- Lucio Ayres Caldas
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Leandro Lemgruber Soares
- Instituto Nacional de Metrologia Normalizacao e Qualidade Industrial, Duque de Caxias, RJ 25250-020, Brazil.,Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, 120 University Place Glasgow, Glasgow G12 8QQ, UK
| | - Sergio Henrique Seabra
- Microbiologia, UEZO, Av. Manuel Caldeira de Alvarenga, Rio de Janeiro, RJ 23070-200, Brazil
| | - Marcia Attias
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Wanderley de Souza
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
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54
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Serpeloni M, Jiménez-Ruiz E, Vidal NM, Kroeber C, Andenmatten N, Lemgruber L, Mörking P, Pall GS, Meissner M, Ávila AR. UAP56 is a conserved crucial component of a divergent mRNA export pathway in Toxoplasma gondii. Mol Microbiol 2016; 102:672-689. [PMID: 27542978 PMCID: PMC5118106 DOI: 10.1111/mmi.13485] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2016] [Indexed: 01/28/2023]
Abstract
Nucleo‐cytoplasmic RNA export is an essential post‐transcriptional step to control gene expression in eukaryotic cells and is poorly understood in apicomplexan parasites. With the exception of UAP56, a component of TREX (Transcription Export) complex, other components of mRNA export machinery are not well conserved in divergent supergroups. Here, we use Toxoplasma gondii as a model system to functionally characterize TgUAP56 and its potential interaction factors. We demonstrate that TgUAP56 is crucial for mRNA export and that functional interference leads to significant accumulation of mRNA in the nucleus. It was necessary to employ bioinformatics and phylogenetic analysis to identify orthologs related to mRNA export, which show a remarkable low level of conservation in T. gondii. We adapted a conditional Cas9/CRISPR system to carry out a genetic screen to verify if these factors were involved in mRNA export in T. gondii. Only the disruption of TgRRM_1330 caused accumulation of mRNA in the nucleus as found with TgUAP56. This protein is potentially a divergent partner of TgUAP56, and provides insight into a divergent mRNA export pathway in apicomplexans.
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Affiliation(s)
- Mariana Serpeloni
- Instituto Carlos Chagas, FIOCRUZ, Curitiba, Brazil.,Departamento de Biologia Celular e Molecular, Universidade Federal do Paraná, Curitiba, Brazil.,College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Elena Jiménez-Ruiz
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Newton Medeiros Vidal
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Constanze Kroeber
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Nicole Andenmatten
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Leandro Lemgruber
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | | | - Gurman S Pall
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
| | - Markus Meissner
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity & Inflammation, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, UK
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55
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Jimenez-Ruiz E, Morlon-Guyot J, Daher W, Meissner M. Vacuolar protein sorting mechanisms in apicomplexan parasites. Mol Biochem Parasitol 2016; 209:18-25. [PMID: 26844642 PMCID: PMC5154328 DOI: 10.1016/j.molbiopara.2016.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 01/14/2016] [Accepted: 01/28/2016] [Indexed: 12/26/2022]
Abstract
The phylum Apicomplexa comprises more than 5000 species including pathogens of clinical and economical importance. These obligate intracellular parasites possess a highly complex endomembrane system to build amongst others three morphologically distinct secretory organelles: rhoptries, micronemes and dense granules. Proteins released by these organelles are essential for invasion and hijacking of the host cell. Due to the complexity of the internal organization of these parasites, a wide panoply of trafficking factors was expected to be required for the correct sorting of proteins towards the various organelles. However, Toxoplasma gondii and other apicomplexan parasites contain only a core set of these factors and several of the vacuolar protein sorting (VPS) homologues found in most eukaryotes have been lost in this phylum. In this review, we will summarise our current knowledge about the role of trafficking complexes in T. gondii, highlighting recent studies focused on complexes formed by VPS proteins. We also present a novel, hypothetical model, suggesting the recycling of parasite membrane and micronemal proteins.
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56
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Morse D, Webster W, Kalanon M, Langsley G, McFadden GI. Plasmodium falciparum Rab1A Localizes to Rhoptries in Schizonts. PLoS One 2016; 11:e0158174. [PMID: 27348424 PMCID: PMC4922565 DOI: 10.1371/journal.pone.0158174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/11/2016] [Indexed: 12/17/2022] Open
Abstract
Over-expression of a GFP-PfRab1A fusion protein in Plasmodium falciparum schizonts produces a punctate pattern of fluorescence typical of rhoptries, secretory organelles involved in host cell invasion. The GFP-positive bodies were purified by a combination of differential and density gradient centrifugation and their protein content determined by MS/MS sequencing. Consistent with the GFP rhoptry-like pattern of transgenic parasites, four of the 19 proteins identified have been previously described to be rhoptry-associated and another four are ER or ER-associated proteins. Confirmation that GFP-PfRab1A decorates rhoptries was obtained by its co-localization with Rap1 and Ron4 in late phase schizonts. We conclude that PfRab1A potentially regulates vesicular traffic from the endoplasmic reticulum to the rhoptries in Apicomplexa parasites.
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Affiliation(s)
- David Morse
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
- * E-mail:
| | - Wesley Webster
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ming Kalanon
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014, Paris, France
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57
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Sangaré LO, Alayi TD, Westermann B, Hovasse A, Sindikubwabo F, Callebaut I, Werkmeister E, Lafont F, Slomianny C, Hakimi MA, Van Dorsselaer A, Schaeffer-Reiss C, Tomavo S. Unconventional endosome-like compartment and retromer complex in Toxoplasma gondii govern parasite integrity and host infection. Nat Commun 2016; 7:11191. [PMID: 27064065 PMCID: PMC4831018 DOI: 10.1038/ncomms11191] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/26/2016] [Indexed: 12/31/2022] Open
Abstract
Membrane trafficking pathways play critical roles in Apicomplexa, a phylum of protozoan parasites that cause life-threatening diseases worldwide. Here we report the first retromer-trafficking interactome in Toxoplasma gondii. This retromer complex includes a trimer Vps35-Vps26-Vps29 core complex that serves as a hub for the endosome-like compartment and parasite-specific proteins. Conditional ablation of TgVps35 reveals that the retromer complex is crucial for the biogenesis of secretory organelles and for maintaining parasite morphology. We identify TgHP12 as a parasite-specific and retromer-associated protein with functions unrelated to secretory organelle formation. Furthermore, the major facilitator superfamily homologue named TgHP03, which is a multiple spanning and ligand transmembrane transporter, is maintained at the parasite membrane by retromer-mediated endocytic recycling. Thus, our findings highlight that both evolutionarily conserved and unconventional proteins act in concert in T. gondii by controlling retrograde transport that is essential for parasite integrity and host infection.
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Affiliation(s)
- Lamba Omar Sangaré
- Center for Infection and Immunity of Lille, INSERM U 1019, CNRS UMR 8204, Institut Pasteur de Lille, Université de Lille, 59000 Lille, France
| | - Tchilabalo Dilezitoko Alayi
- Laboratory of Bio-Organic Mass Spectrometry, IPHC, CNRS UMR 7178, Université de Strasbourg, 67087 Strasbourg, France
- Plateforme de Protéomique et des Peptides Modifiés (P3M), Institut Pasteur de Lille, CNRS, Université de Lille, 59000 Lille, France
| | - Benoit Westermann
- Laboratory of Bio-Organic Mass Spectrometry, IPHC, CNRS UMR 7178, Université de Strasbourg, 67087 Strasbourg, France
| | - Agnes Hovasse
- Laboratory of Bio-Organic Mass Spectrometry, IPHC, CNRS UMR 7178, Université de Strasbourg, 67087 Strasbourg, France
| | | | - Isabelle Callebaut
- CNRS UMR7590, Sorbonne Universités, Université Pierre et Marie Curie-Paris 6, MNHN, IRD-IUC, Paris 75005, France
| | | | - Frank Lafont
- Bioimaging Platform, IBL, CNRS, Université de Lille, 59000 Lille, France
| | - Christian Slomianny
- Laboratory of Cell Physiology, INSERM U 1003, Université de Lille, 59655 Villeneuve d'Ascq, France
| | | | - Alain Van Dorsselaer
- Laboratory of Bio-Organic Mass Spectrometry, IPHC, CNRS UMR 7178, Université de Strasbourg, 67087 Strasbourg, France
| | - Christine Schaeffer-Reiss
- Laboratory of Bio-Organic Mass Spectrometry, IPHC, CNRS UMR 7178, Université de Strasbourg, 67087 Strasbourg, France
| | - Stanislas Tomavo
- Center for Infection and Immunity of Lille, INSERM U 1019, CNRS UMR 8204, Institut Pasteur de Lille, Université de Lille, 59000 Lille, France
- Plateforme de Protéomique et des Peptides Modifiés (P3M), Institut Pasteur de Lille, CNRS, Université de Lille, 59000 Lille, France
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58
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Mueller C, Samoo A, Hammoudi PM, Klages N, Kallio JP, Kursula I, Soldati-Favre D. Structural and functional dissection of Toxoplasma gondii armadillo repeats only protein (TgARO). J Cell Sci 2016; 129:1031-45. [DOI: 10.1242/jcs.177386] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/07/2016] [Indexed: 02/03/2023] Open
Abstract
Rhoptries are club-shaped, regulated secretory organelles that cluster at the apical pole of apicomplexan parasites. Their discharge is essential for invasion and the establishment of an intracellular lifestyle. Little is known about rhoptry biogenesis and recycling during parasite division. In Toxoplasma gondii, positioning of rhoptries involves the armadillo repeats only protein (TgARO) and myosin F (TgMyoF). Here, we show that two TgARO partners, ARO interacting protein (TgAIP) and adenylate cyclase β (TgACβ) localize to a rhoptry subcompartment. In absence of TgAIP, TgACβ disappears from the rhoptries. By assessing the contribution of each TgARO armadillo (ARM) repeat, we provide evidence that TgARO is multifunctional, participating not only in positioning but also in clustering of rhoptries. Structural analyses show that TgARO resembles the myosin-binding domain of the myosin chaperone UNC-45. A conserved patch of aromatic and acidic residues denotes the putative TgMyoF-binding site, and the overall arrangement of the ARM repeats explains the dramatic consequences of deleting each of them. Lastly, Plasmodium falciparum ARO functionally complements TgARO depletion and interacts with the same partners, highlighting the conservation of rhoptry biogenesis in Apicomplexa.
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Affiliation(s)
- Christina Mueller
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Atta Samoo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, 90014 Oulu, Finland
- Helmholtz Centre for Infection Research, Notkestrasse 85, 22607 Hamburg, Germany
- German Electron Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Natacha Klages
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Juha Pekka Kallio
- Helmholtz Centre for Infection Research, Notkestrasse 85, 22607 Hamburg, Germany
- German Electron Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Inari Kursula
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, 90014 Oulu, Finland
- Helmholtz Centre for Infection Research, Notkestrasse 85, 22607 Hamburg, Germany
- German Electron Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
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59
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Stewart RJ, Ferguson DJP, Whitehead L, Bradin CH, Wu HJ, Tonkin CJ. Phosphorylation of αSNAP is Required for Secretory Organelle Biogenesis inToxoplasma gondii. Traffic 2015; 17:102-16. [DOI: 10.1111/tra.12348] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Rebecca J. Stewart
- The Walter and Eliza Hall Institute of Medical Research; Melbourne 3052 Australia
- The Department of Medical Biology; The University of Melbourne; Melbourne 3010 Australia
| | - David J. P. Ferguson
- Nuffield Department of Clinical Laboratory Science; Oxford University, John Radcliffe Hospital; Oxford OX3 9DU UK
| | - Lachlan Whitehead
- The Walter and Eliza Hall Institute of Medical Research; Melbourne 3052 Australia
| | - Clare H. Bradin
- The Walter and Eliza Hall Institute of Medical Research; Melbourne 3052 Australia
| | - Hong J. Wu
- The Walter and Eliza Hall Institute of Medical Research; Melbourne 3052 Australia
- The Department of Medical Biology; The University of Melbourne; Melbourne 3010 Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research; Melbourne 3052 Australia
- The Department of Medical Biology; The University of Melbourne; Melbourne 3010 Australia
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60
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Coffey MJ, Sleebs BE, Uboldi AD, Garnham A, Franco M, Marino ND, Panas MW, Ferguson DJP, Enciso M, O'Neill MT, Lopaticki S, Stewart RJ, Dewson G, Smyth GK, Smith BJ, Masters SL, Boothroyd JC, Boddey JA, Tonkin CJ. An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell. eLife 2015; 4:e10809. [PMID: 26576949 PMCID: PMC4764566 DOI: 10.7554/elife.10809] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/18/2015] [Indexed: 02/03/2023] Open
Abstract
Infection by Toxoplasma gondii leads to massive changes to the host cell. Here, we identify a novel host cell effector export pathway that requires the Golgi-resident aspartyl protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures substrates at both the N- and C-terminal ends of proteins and also controls trafficking of effectors without this motif. Furthermore, ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the vacuole. Assessment of host gene expression reveals that the ASP5-dependent pathway influences thousands of the transcriptional changes that Toxoplasma imparts on its host cell. All these changes result in attenuation of virulence of Δasp5 tachyzoites in vivo. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell.
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Affiliation(s)
- Michael J Coffey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alessandro D Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alexandra Garnham
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Magdalena Franco
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Nicole D Marino
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Michael W Panas
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - David JP Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom
| | - Marta Enciso
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Rebecca J Stewart
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Gordon K Smyth
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Seth L Masters
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
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61
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Abstract
Toxoplasmosis is the clinical and pathological consequence of acute infection with the obligate intracellular apicomplexan parasite Toxoplasma gondii. Symptoms result from tissue destruction that accompanies lytic parasite growth. This review updates current understanding of the host cell invasion, parasite replication, and eventual egress that constitute the lytic cycle, as well as the ways T. gondii manipulates host cells to ensure its survival. Since the publication of a previous iteration of this review 15 years ago, important advances have been made in our molecular understanding of parasite growth and mechanisms of host cell egress, and knowledge of the parasite's manipulation of the host has rapidly progressed. Here we cover molecular advances and current conceptual frameworks that include each of these topics, with an eye to what may be known 15 years from now.
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Affiliation(s)
- Ira J Blader
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, New York 14127;
| | - Bradley I Coleman
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467; , ,
| | - Chun-Ti Chen
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467; , ,
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467; , ,
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62
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Pieperhoff MS, Pall GS, Jiménez-Ruiz E, Das S, Melatti C, Gow M, Wong EH, Heng J, Müller S, Blackman MJ, Meissner M. Conditional U1 Gene Silencing in Toxoplasma gondii. PLoS One 2015; 10:e0130356. [PMID: 26090798 PMCID: PMC4474610 DOI: 10.1371/journal.pone.0130356] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 05/18/2015] [Indexed: 11/19/2022] Open
Abstract
The functional characterisation of essential genes in apicomplexan parasites, such as Toxoplasma gondii or Plasmodium falciparum, relies on conditional mutagenesis systems. Here we present a novel strategy based on U1 snRNP-mediated gene silencing. U1 snRNP is critical in pre-mRNA splicing by defining the exon-intron boundaries. When a U1 recognition site is placed into the 3'-terminal exon or adjacent to the termination codon, pre-mRNA is cleaved at the 3'-end and degraded, leading to an efficient knockdown of the gene of interest (GOI). Here we describe a simple method that combines endogenous tagging with DiCre-mediated positioning of U1 recognition sites adjacent to the termination codon of the GOI which leads to a conditional knockdown of the GOI upon rapamycin-induction. Specific knockdown mutants of the reporter gene GFP and several endogenous genes of T. gondii including the clathrin heavy chain gene 1 (chc1), the vacuolar protein sorting gene 26 (vps26), and the dynamin-related protein C gene (drpC) were silenced using this approach and demonstrate the potential of this technology. We also discuss advantages and disadvantages of this method in comparison to other technologies in more detail.
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Affiliation(s)
- Manuela S. Pieperhoff
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Gurman S. Pall
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Elena Jiménez-Ruiz
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Sujaan Das
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Carmen Melatti
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Matthew Gow
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Eleanor H. Wong
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Joanne Heng
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Sylke Müller
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
| | - Michael J. Blackman
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
- * E-mail: (MM); (MJB)
| | - Markus Meissner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow, Lanarkshire, United Kingdom
- * E-mail: (MM); (MJB)
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63
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Morlon‐Guyot J, Pastore S, Berry L, Lebrun M, Daher W. Toxoplasma gondii
Vps11, a subunit of
HOPS
and
CORVET
tethering complexes, is essential for the biogenesis of secretory organelles. Cell Microbiol 2015; 17:1157-78. [DOI: 10.1111/cmi.12426] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 01/20/2015] [Accepted: 01/28/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Juliette Morlon‐Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Sandra Pastore
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Laurence Berry
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
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64
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Kaderi Kibria KM, Rawat K, Klinger CM, Datta G, Panchal M, Singh S, Iyer GR, Kaur I, Sharma V, Dacks JB, Mohmmed A, Malhotra P. A role for adaptor protein complex 1 in protein targeting to rhoptry organelles in Plasmodium falciparum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:699-710. [PMID: 25573429 DOI: 10.1016/j.bbamcr.2014.12.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 12/12/2014] [Accepted: 12/25/2014] [Indexed: 12/20/2022]
Abstract
The human malaria parasite Plasmodium falciparum possesses sophisticated systems of protein secretion to modulate host cell invasion and remodeling. In the present study, we provide insights into the function of the AP-1 complex in P. falciparum. We utilized GFP fusion constructs for live cell imaging, as well as fixed parasites in immunofluorescence analysis, to study adaptor protein mu1 (Pfμ1) mediated protein trafficking in P. falciparum. In trophozoites Pfμ1 showed similar dynamic localization to that of several Golgi/ER markers, indicating Golgi/ER localization. Treatment of transgenic parasites with Brefeldin A altered the localization of Golgi-associated Pfμ1, supporting the localization studies. Co-localization studies showed considerable overlap of Pfμ1 with the resident rhoptry proteins, rhoptry associated protein 1 (RAP1) and Cytoadherence linked asexual gene 3.1 (Clag3.1) in schizont stage. Immunoprecipitation experiments with Pfμ1 and PfRAP1 revealed an interaction, which may be mediated through an intermediate transmembrane cargo receptor. A specific role for Pfμ1 in trafficking was suggested by treatment with AlF4, which resulted in a shift to a predominantly ER-associated compartment and consequent decrease in co-localization with the Golgi marker GRASP. Together, these results suggest a role for the AP-1 complex in rhoptry protein trafficking in P. falciparum.
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Affiliation(s)
- K M Kaderi Kibria
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Khushboo Rawat
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Christen M Klinger
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Gaurav Datta
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Manoj Panchal
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Shailja Singh
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Gayatri R Iyer
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Inderjeet Kaur
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Veena Sharma
- Department of Bioscience and Biotechnology, Banasthali University, Banasthali-304022, Rajasthan, India
| | - Joel B Dacks
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.
| | - Asif Mohmmed
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
| | - Pawan Malhotra
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
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65
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Salamun J, Kallio JP, Daher W, Soldati-Favre D, Kursula I. Structure of Toxoplasma gondii coronin, an actin-binding protein that relocalizes to the posterior pole of invasive parasites and contributes to invasion and egress. FASEB J 2014; 28:4729-47. [PMID: 25114175 DOI: 10.1096/fj.14-252569] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Coronins are involved in the regulation of actin dynamics in a multifaceted way, participating in cell migration and vesicular trafficking. Apicomplexan parasites, which exhibit an actin-dependent gliding motility that is essential for traversal through tissues, as well as invasion of and egress from host cells, express only a single coronin, whereas higher eukaryotes possess several isoforms. We set out to characterize the 3-D structure, biochemical function, subcellular localization, and genetic ablation of Toxoplasma gondii coronin (TgCOR), to shed light on its biological role. A combination of X-ray crystallography, small-angle scattering of X-rays, and light scattering revealed the atomic structure of the conserved WD40 domain and the dimeric arrangement of the full-length protein. TgCOR binds to F-actin and increases the rate and extent of actin polymerization. In vivo, TgCOR relocalizes transiently to the posterior pole of motile and invading parasites, independent of actin dynamics, but concomitant to microneme secretory organelle discharge. TgCOR contributes to, but is not essential for, invasion and egress. Taken together, our data point toward a role for TgCOR in stabilizing newly formed, short filaments and F-actin cross-linking, as well as functions linked to endocytosis and recycling of membranes.
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Affiliation(s)
- Julien Salamun
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Juha P Kallio
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and German Electron Synchrotron (DESY), Hamburg, Germany; and
| | - Wassim Daher
- 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;
| | - Inari Kursula
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and German Electron Synchrotron (DESY), Hamburg, Germany; and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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66
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A conserved apicomplexan microneme protein contributes to Toxoplasma gondii invasion and virulence. Infect Immun 2014; 82:4358-68. [PMID: 25092910 DOI: 10.1128/iai.01877-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii critically relies on host cell invasion during infection. Proteins secreted from the apical micronemes are central components for host cell recognition, invasion, egress, and virulence. Although previous work established that the sporozoite protein with an altered thrombospondin repeat (SPATR) is a micronemal protein conserved in other apicomplexan parasites, including Plasmodium, Neospora, and Eimeria, no genetic evidence of its contribution to invasion has been reported. SPATR contains a predicted epidermal growth factor domain and two thrombospondin type 1 repeats, implying a role in host cell recognition. In this study, we assess the contribution of T. gondii SPATR (TgSPATR) to T. gondii invasion by genetically ablating it and restoring its expression by genetic complementation. Δspatr parasites were ~50% reduced in invasion compared to parental strains, a defect that was reversed in the complemented strain. In mouse virulence assays, Δspatr parasites were significantly attenuated, with ~20% of mice surviving infection. Given the conservation of this protein among the Apicomplexa, we assessed whether the Plasmodium falciparum SPATR ortholog (PfSPATR) could complement the absence of the TgSPATR. Although PfSPATR showed correct micronemal localization, it did not reverse the invasion deficiency of Δspatr parasites, because of an apparent failure in secretion. Overall, the results suggest that TgSPATR contributes to invasion and virulence, findings that have implications for the many genera and life stages of apicomplexans that express SPATR.
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67
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Abstract
The protozoan parasite Toxoplasma gondii resides within a nonfusogenic vacuole during intracellular replication. Although the limiting membrane of this vacuole provides a protective barrier to acidification and degradation by lysosomal hydrolases, it also physically segregates the parasite from the host cytosol. Accordingly, it has been suggested that T. gondii acquires material from the host via membrane channels or transporters. The ability of the parasite to internalize macromolecules via endocytosis during intracellular replication has not been tested. Here, we show that Toxoplasma ingests host cytosolic proteins and digests them using cathepsin L and other proteases within its endolysosomal system. Ingestion was reduced in mutant parasites lacking an intravacuolar network of tubular membranes, implicating this apparatus as a possible conduit for trafficking to the parasite. Genetic ablation of proteins involved in the pathway is associated with diminished parasite replication and virulence attenuation. We show that both virulent type I and avirulent type II strain parasites ingest and digest host-derived protein, indicating that the pathway is not restricted to highly virulent strains. The findings provide the first definitive evidence that T. gondii internalizes proteins from the host during intracellular residence and suggest that protein digestion within the endolysosomal system of the parasite contributes to toxoplasmosis. Toxoplasma gondii causes significant disease in individuals with weak immune systems. Treatment options for this infection have drawbacks, creating a need to understand how this parasite survives within the cells it infects as a prelude to interrupting its survival strategies. This study reveals that T. gondii internalizes proteins from the cytoplasm of the cells it infects and degrades such proteins within a digestive compartment within the parasite. Disruption of proteins involved in the pathway reduced parasite replication and lessened disease severity. The identification of a novel parasite ingestion pathway opens opportunities to interfere with this process and improve the outcome of infection.
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68
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Advantages and disadvantages of conditional systems for characterization of essential genes in Toxoplasma gondii. Parasitology 2014; 141:1390-8. [PMID: 24926834 DOI: 10.1017/s0031182014000559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The dissection of apicomplexan biology has been highly influenced by the genetic tools available for manipulation of parasite DNA. Here, we describe different techniques available for the generation of conditional mutants. Comparison of the advantages and disadvantages of the three most commonly used regulation systems: the tetracycline inducible system, the regulation of protein stability and site-specific recombination are discussed. Using some previously described examples we explore some of the pitfalls involved in gene-function analysis using these systems that can lead to wrong or over-interpretation of phenotypes. We will also mention different options to standardize the application of these techniques for the characterization of gene function in high-throughput.
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69
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Evolutionary repurposing of endosomal systems for apical organelle biogenesis in Toxoplasma gondii. Int J Parasitol 2014; 44:133-8. [DOI: 10.1016/j.ijpara.2013.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 12/20/2022]
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70
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Tomavo S, Slomianny C, Meissner M, Carruthers VB. Protein trafficking through the endosomal system prepares intracellular parasites for a home invasion. PLoS Pathog 2013; 9:e1003629. [PMID: 24204248 PMCID: PMC3812028 DOI: 10.1371/journal.ppat.1003629] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Toxoplasma (toxoplasmosis) and Plasmodium (malaria) use unique secretory organelles for migration, cell invasion, manipulation of host cell functions, and cell egress. In particular, the apical secretory micronemes and rhoptries of apicomplexan parasites are essential for successful host infection. New findings reveal that the contents of these organelles, which are transported through the endoplasmic reticulum (ER) and Golgi, also require the parasite endosome-like system to access their respective organelles. In this review, we discuss recent findings that demonstrate that these parasites reduced their endosomal system and modified classical regulators of this pathway for the biogenesis of apical organelles.
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Affiliation(s)
- Stanislas Tomavo
- Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U 1019, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
- * E-mail:
| | - Christian Slomianny
- Laboratory of Cell Physiology, INSERM U 1003, Université Lille Nord de France, Villeneuve d'Ascq, Lille, France
| | - Markus Meissner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
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71
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The role of clathrin in post-Golgi trafficking in Toxoplasma gondii. PLoS One 2013; 8:e77620. [PMID: 24147036 PMCID: PMC3795686 DOI: 10.1371/journal.pone.0077620] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 09/13/2013] [Indexed: 11/19/2022] Open
Abstract
Apicomplexan parasites are single eukaryotic cells with a highly polarised secretory system that contains unique secretory organelles (micronemes and rhoptries) that are required for host cell invasion. In contrast, the role of the endosomal system is poorly understood in these parasites. With many typical endocytic factors missing, we speculated that endocytosis depends exclusively on a clathrin-mediated mechanism. Intriguingly, in Toxoplasma gondii we were only able to observe the endogenous clathrin heavy chain 1 (CHC1) at the Golgi, but not at the parasite surface. For the functional characterisation of Toxoplasma gondii CHC1 we generated parasite mutants conditionally expressing the dominant negative clathrin Hub fragment and demonstrate that CHC1 is essential for vesicle formation at the trans-Golgi network. Consequently, the functional ablation of CHC1 results in Golgi aberrations, a block in the biogenesis of the unique secretory microneme and rhoptry organelles, and of the pellicle. However, we found no morphological evidence for clathrin mediating endocytosis in these parasites and speculate that they remodelled their vesicular trafficking system to adapt to an intracellular lifestyle.
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72
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Caldas LA, Seabra SH, Attias M, de Souza W. The effect of kinase, actin, myosin and dynamin inhibitors on host cell egress by Toxoplasma gondii. Parasitol Int 2013; 62:475-82. [DOI: 10.1016/j.parint.2013.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 03/26/2013] [Accepted: 04/18/2013] [Indexed: 12/21/2022]
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73
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Comparative genomic analysis of multi-subunit tethering complexes demonstrates an ancient pan-eukaryotic complement and sculpting in Apicomplexa. PLoS One 2013; 8:e76278. [PMID: 24086721 PMCID: PMC3785458 DOI: 10.1371/journal.pone.0076278] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/22/2013] [Indexed: 11/19/2022] Open
Abstract
Apicomplexa are obligate intracellular parasites that cause tremendous disease burden world-wide. They utilize a set of specialized secretory organelles in their invasive process that require delivery of components for their biogenesis and function, yet the precise mechanisms underpinning such processes remain unclear. One set of potentially important components is the multi-subunit tethering complexes (MTCs), factors increasingly implicated in all aspects of vesicle-target interactions. Prompted by the results of previous studies indicating a loss of membrane trafficking factors in Apicomplexa, we undertook a bioinformatic analysis of MTC conservation. Building on knowledge of the ancient presence of most MTC proteins, we demonstrate the near complete retention of MTCs in the newly available genomes for Guillardiatheta and Bigelowiellanatans. The latter is a key taxonomic sampling point as a basal sister taxa to the group including Apicomplexa. We also demonstrate an ancient origin of the CORVET complex subunits Vps8 and Vps3, as well as the TRAPPII subunit Tca17. Having established that the lineage leading to Apicomplexa did at one point possess the complete eukaryotic complement of MTC components, we undertook a deeper taxonomic investigation in twelve apicomplexan genomes. We observed excellent conservation of the VpsC core of the HOPS and CORVET complexes, as well as the core TRAPP subunits, but sparse conservation of TRAPPII, COG, Dsl1, and HOPS/CORVET-specific subunits. However, those subunits that we did identify appear to be expressed with similar patterns to the fully conserved MTC proteins, suggesting that they may function as minimal complexes or with analogous partners. Strikingly, we failed to identify any subunits of the exocyst complex in all twelve apicomplexan genomes, as well as the dinoflagellate Perkinsus marinus. Overall, we demonstrate reduction of MTCs in Apicomplexa and their ancestors, consistent with modification during, and possibly pre-dating, the move from free-living marine algae to deadly human parasites.
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74
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Jackson AJ, Clucas C, Mamczur NJ, Ferguson DJ, Meissner M. Toxoplasma gondii Syntaxin 6 is required for vesicular transport between endosomal-like compartments and the Golgi complex. Traffic 2013; 14:1166-81. [PMID: 23962112 PMCID: PMC3963449 DOI: 10.1111/tra.12102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/15/2013] [Accepted: 08/20/2013] [Indexed: 11/28/2022]
Abstract
Apicomplexans are obligate intracellular parasites that invade the host cell in an active process that relies on unique secretory organelles (micronemes, rhoptries and dense granules) localized at the apical tip of these highly polarized eukaryotes. In order for the contents of these specialized organelles to reach their final destination, these proteins are sorted post-Golgi and it has been speculated that they pass through endosomal-like compartments (ELCs), where they undergo maturation. Here, we characterize a Toxoplasma gondii homologue of Syntaxin 6 (TgStx6), a well-established marker for the early endosomes and trans Golgi network (TGN) in diverse eukaryotes. Indeed, TgStx6 appears to have a role in the retrograde transport between ELCs, the TGN and the Golgi, because overexpression of TgStx6 results in the development of abnormally shaped parasites with expanded ELCs, a fragmented Golgi and a defect in inner membrane complex maturation. Interestingly, other organelles such as the micronemes, rhoptries and the apicoplast are not affected, establishing the TGN as a major sorting compartment where several transport pathways intersect. It therefore appears that Toxoplasma has retained a plant-like secretory pathway.
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Affiliation(s)
- Allison J Jackson
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, G12 8TA, UK
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75
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Morlon-Guyot J, Berry L, Chen CT, Gubbels MJ, Lebrun M, Daher W. The Toxoplasma gondii calcium-dependent protein kinase 7 is involved in early steps of parasite division and is crucial for parasite survival. Cell Microbiol 2013; 16:95-114. [PMID: 24011186 DOI: 10.1111/cmi.12186] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/12/2013] [Accepted: 08/14/2013] [Indexed: 12/22/2022]
Abstract
Apicomplexan parasites express various calcium-dependent protein kinases (CDPKs), and some of them play essential roles in invasion and egress. Five of the six CDPKs conserved in most Apicomplexa have been studied at the molecular and cellular levels in Plasmodium species and/or in Toxoplasma gondii parasites, but the function of CDPK7 was so far uncharacterized. In T. gondii, during intracellular replication, two parasites are formed within a mother cell through a unique process called endodyogeny. Here we demonstrate that the knock-down of CDPK7 protein in T. gondii results in pronounced defects in parasite division and a major growth deficiency, while it is dispensable for motility, egress and microneme exocytosis. In cdpk7-depleted parasites, the overall DNA content was not impaired, but the polarity of daughter cells budding and the fate of several subcellular structures or proteins involved in cell division were affected, such as the centrosomes and the kinetochore. Overall, our data suggest that CDPK7 is crucial for proper maintenance of centrosome integrity required for the initiation of endodyogeny. Our findings provide a first insight into the probable role of calcium-dependent signalling in parasite multiplication, in addition to its more widely explored role in invasion and egress.
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Affiliation(s)
- Juliette Morlon-Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, Université de Montpellier I et II, Montpellier, France
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76
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Klinger CM, Nisbet RE, Ouologuem DT, Roos DS, Dacks JB. Cryptic organelle homology in apicomplexan parasites: insights from evolutionary cell biology. Curr Opin Microbiol 2013; 16:424-31. [PMID: 23932202 PMCID: PMC4513074 DOI: 10.1016/j.mib.2013.07.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/18/2013] [Accepted: 07/23/2013] [Indexed: 12/21/2022]
Abstract
The economic and clinical significance of apicomplexan parasites drives interest in their many evolutionary novelties. Distinctive intracellular organelles play key roles in parasite motility, invasion, metabolism, and replication, and understanding their relationship with the organelles of better-studied eukaryotic systems suggests potential targets for therapeutic intervention. Recent work has demonstrated divergent aspects of canonical eukaryotic components in the Apicomplexa, including Golgi bodies and mitochondria. The apicoplast is a relict plastid of secondary endosymbiotic origin, harboring metabolic pathways distinct from those of host species. The inner membrane complex (IMC) is derived from the cortical alveoli defining the superphylum Alveolata, but in apicomplexans functions in parasite motility and replication. Micronemes and rhoptries are associated with establishment of the intracellular niche, and define the apical complex for which the phylum is named. Morphological, cell biological and molecular evidence strongly suggest that these organelles are derived from the endocytic pathway.
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Affiliation(s)
| | - R. Ellen Nisbet
- Department of Biochemistry, Cambridge University, Cambridge UK and School of Pharmacy and Medical Sciences, University of South Australia, Adelaide SA, Australia
- Department of Biology, University of Pennsylvania, Philadelphia PA USA
| | | | | | - Joel B. Dacks
- Department of Cell Biology, University of Alberta, Edmonton AB, Canada
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77
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Jacot D, Daher W, Soldati-Favre D. Toxoplasma gondii myosin F, an essential motor for centrosomes positioning and apicoplast inheritance. EMBO J 2013; 32:1702-16. [PMID: 23695356 DOI: 10.1038/emboj.2013.113] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/22/2013] [Indexed: 11/09/2022] Open
Abstract
Members of the Apicomplexa phylum possess an organelle surrounded by four membranes, originating from the secondary endosymbiosis of a red alga. This so-called apicoplast hosts essential metabolic pathways. We report here that apicoplast inheritance is an actin-based process. Concordantly, parasites depleted in either profilin or actin depolymerizing factor, or parasites overexpressing the FH2 domain of formin 2, result in loss of the apicoplast. The class XXII myosin F (MyoF) is conserved across the phylum and localizes in the vicinity of the Toxoplasma gondii apicoplast during division. Conditional knockdown of TgMyoF severely affects apicoplast turnover, leading to parasite death. This recapitulates the phenotype observed upon perturbation of actin dynamics that led to the accumulation of the apicoplast and secretory organelles in enlarged residual bodies. To further dissect the mode of action of this motor, we conditionally stabilized the tail of MyoF, which forms an inactive heterodimer with endogenous TgMyoF. This dominant negative mutant reveals a central role of this motor in the positioning of the two centrosomes prior to daughter cell formation and in apicoplast segregation.
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Affiliation(s)
- Damien Jacot
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
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78
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Lourido S, Jeschke GR, Turk BE, Sibley LD. Exploiting the unique ATP-binding pocket of toxoplasma calcium-dependent protein kinase 1 to identify its substrates. ACS Chem Biol 2013; 8:1155-62. [PMID: 23530747 PMCID: PMC3691715 DOI: 10.1021/cb400115y] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
![]()
Apicomplexan parasites rely on calcium
as a second messenger to
regulate a variety of essential cellular processes. Calcium-dependent
protein kinases (CDPK), which transduce these signals, are conserved
among apicomplexans but absent from mammalian hosts, making them attractive
targets for therapeutic intervention. Despite their importance, the
signaling pathways CDPK regulate remain poorly characterized, and
their protein substrates are completely unknown. In Toxoplasma
gondii, CDPK1 is required for calcium-regulated secretion
from micronemes, thereby controlling motility, invasion, and egress
from host cells. CDPK1 is unique among parasite and mammalian kinases
in containing glycine at the key “gatekeeper” residue,
which results in an expanded ATP-binding pocket. In the present study,
we use a synthetic ATPγS analogue that displays steric complementarity
to the ATP-binding pocket and hence allows identification of protein
substrates based on selective thiophosphorylation. The specificity
of this approach was validated by the concordance between the identified
phosphorylation sites and the in vitro substrate
preference of CDPK1. We further demonstrate that the phosphorylation
of predicted substrates is dependent on CDPK1 both in vivo and in vitro. This combined strategy for identifying
the targets of specific protein kinases provides a platform for defining
the roles of CDPKs in apicomplexans.
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Affiliation(s)
- Sebastian Lourido
- Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid
Ave., St. Louis, Missouri 63110, United States
| | - Grace R. Jeschke
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St.,
New Haven, Connecticut 06520, United States
| | - Benjamin E. Turk
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St.,
New Haven, Connecticut 06520, United States
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid
Ave., St. Louis, Missouri 63110, United States
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79
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Counihan NA, Kalanon M, Coppel RL, de Koning-Ward TF. Plasmodium rhoptry proteins: why order is important. Trends Parasitol 2013; 29:228-36. [PMID: 23570755 DOI: 10.1016/j.pt.2013.03.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 02/28/2013] [Accepted: 03/04/2013] [Indexed: 11/26/2022]
Abstract
Apicomplexan parasites, including the Plasmodium species that cause malaria, contain three unusual apical secretory organelles (micronemes, rhoptries, and dense granules) that are required for the infection of new host cells. Because of their specialized nature, the majority of proteins secreted from these organelles are unique to Apicomplexans and are consequently poorly characterized. Although rhoptry proteins of Plasmodium have been implicated in events central to invasion, there is growing evidence to suggest that proteins originating from this organelle play key roles downstream of parasite entry into the host cell. Here we discuss recent work that has advanced our knowledge of rhoptry protein trafficking and function, and highlight areas of research that require further investigation.
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Kremer K, Kamin D, Rittweger E, Wilkes J, Flammer H, Mahler S, Heng J, Tonkin CJ, Langsley G, Hell SW, Carruthers VB, Ferguson DJP, Meissner M. An overexpression screen of Toxoplasma gondii Rab-GTPases reveals distinct transport routes to the micronemes. PLoS Pathog 2013; 9:e1003213. [PMID: 23505371 PMCID: PMC3591302 DOI: 10.1371/journal.ppat.1003213] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/10/2013] [Indexed: 12/20/2022] Open
Abstract
The basic organisation of the endomembrane system is conserved in all eukaryotes and comparative genome analyses provides compelling evidence that the endomembrane system of the last common eukaryotic ancestor (LCEA) is complex with many genes required for regulated traffic being present. Although apicomplexan parasites, causative agents of severe human and animal diseases, appear to have only a basic set of trafficking factors such as Rab-GTPases, they evolved unique secretory organelles (micronemes, rhoptries and dense granules) that are sequentially secreted during invasion of the host cell. In order to define the secretory pathway of apicomplexans, we performed an overexpression screen of Rabs in Toxoplasma gondii and identified Rab5A and Rab5C as important regulators of traffic to micronemes and rhoptries. Intriguingly, we found that not all microneme proteins traffic depends on functional Rab5A and Rab5C, indicating the existence of redundant microneme targeting pathways. Using two-colour super-resolution stimulated emission depletion (STED) we verified distinct localisations of independent microneme proteins and demonstrate that micronemal organelles are organised in distinct subsets or subcompartments. Our results suggest that apicomplexan parasites modify classical regulators of the endocytic system to carryout essential parasite-specific roles in the biogenesis of their unique secretory organelles. Eukaryotic cells evolved a highly complex endomembrane system, consisting of secretory and endocytic organelles. In the case of apicomplexan parasites unique secretory organelles have evolved that are essential for the invasion of the host cell. Surprisingly these protozoans show a paucity of trafficking factors, such as Rabs and it appears that they lost several factors involved in endocytosis. Here, we demonstrate that Rab5A and Rab5C, normally involved in endocytic uptake, actually regulate secretion in Toxoplasma gondii, since functional ablation of Rab5A or Rab5C results in aberrant transport of proteins to specialised secretory organelles called micronemes and rhoptries. Furthermore, we demonstrate that independent transport routes to micronemes exist indicating that apicomplexans have remodelled Rab5-mediated vesicular traffic into a secretory system that is essential for host cell invasion.
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Affiliation(s)
- Katrin Kremer
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Dirk Kamin
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Eva Rittweger
- German Cancer Research Center/BioQuant, Heidelberg, Germany
| | - Jonathan Wilkes
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Halley Flammer
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Sabine Mahler
- Parasitology, Department of Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
| | - Joanne Heng
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | | | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Institut Cochin, Inserm, U567, CNRS, UMR 8104, Faculté de Médecine Paris V – Hôpital Cochin, Paris, France
| | - Stefan W. Hell
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vernon B. Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - David J. P. Ferguson
- Nuffield Department of Pathology, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Markus Meissner
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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81
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Mueller C, Klages N, Jacot D, Santos J, Cabrera A, Gilberger T, Dubremetz JF, Soldati-Favre D. The Toxoplasma Protein ARO Mediates the Apical Positioning of Rhoptry Organelles, a Prerequisite for Host Cell Invasion. Cell Host Microbe 2013; 13:289-301. [DOI: 10.1016/j.chom.2013.02.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 01/04/2013] [Accepted: 01/29/2013] [Indexed: 10/27/2022]
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82
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Beck JR, Fung C, Straub KW, Coppens I, Vashisht AA, Wohlschlegel JA, Bradley PJ. A Toxoplasma palmitoyl acyl transferase and the palmitoylated armadillo repeat protein TgARO govern apical rhoptry tethering and reveal a critical role for the rhoptries in host cell invasion but not egress. PLoS Pathog 2013; 9:e1003162. [PMID: 23408890 PMCID: PMC3567180 DOI: 10.1371/journal.ppat.1003162] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022] Open
Abstract
Apicomplexans are obligate intracellular parasites that actively penetrate their host cells to create an intracellular niche for replication. Commitment to invasion is thought to be mediated by the rhoptries, specialized apical secretory organelles that inject a protein complex into the host cell to form a tight-junction for parasite entry. Little is known about the molecular factors that govern rhoptry biogenesis, their subcellular organization at the apical end of the parasite and subsequent release of this organelle during invasion. We have identified a Toxoplasma palmitoyl acyltransferase, TgDHHC7, which localizes to the rhoptries. Strikingly, conditional knockdown of TgDHHC7 results in dispersed rhoptries that fail to organize at the apical end of the parasite and are instead scattered throughout the cell. While the morphology and content of these rhoptries appears normal, failure to tether at the apex results in a complete block in host cell invasion. In contrast, attachment and egress are unaffected in the knockdown, demonstrating that the rhoptries are not required for these processes. We show that rhoptry targeting of TgDHHC7 requires a short, highly conserved C-terminal region while a large, divergent N-terminal domain is dispensable for both targeting and function. Additionally, a point mutant lacking a key residue predicted to be critical for enzyme activity fails to rescue apical rhoptry tethering, strongly suggesting that tethering of the organelle is dependent upon TgDHHC7 palmitoylation activity. We tie the importance of this activity to the palmitoylated Armadillo Repeats-Only (TgARO) rhoptry protein by showing that conditional knockdown of TgARO recapitulates the dispersed rhoptry phenotype of TgDHHC7 knockdown. The unexpected finding that apicomplexans have exploited protein palmitoylation for apical organelle tethering yields new insight into the biogenesis and function of rhoptries and may provide new avenues for therapeutic intervention against Toxoplasma and related apicomplexan parasites. Apicomplexans possess a highly polarized secretory pathway that is critical for their ability to invade host cells and cause disease. This unique cellular organization enables delivery of protein cargo to specialized secretory organelles called micronemes and rhoptries that drive forward penetration into the host cell. The rhoptries are tethered in a bundle at the apex of the parasite, but how these organelles are organized in this manner is unknown. In this work, we identify a rhoptry-localized palmitoyl acyl transferase (named TgDHHC7) that functions to properly affix the rhoptries at the apical end of the parasite. Conditional disruption of TgDHHC7 results in a failure to tether the rhoptries at the cell apex and a corresponding loss of rhoptry function. We exploit this mutant to clearly demonstrate a critical role for the rhoptries in host invasion but not attachment or egress. Additionally, we find that mutation of a key residue predicted to be required for catalytic activity renders TgDHHC7 non-functional and that knockdown of the candidate substrate TgARO produces an identical phenotype to loss of TgDHHC7. The finding that Toxoplasma employs protein palmitoylation to position the rhoptries at the cell apex provides new insight into the molecular mechanisms that underlie apicomplexan cell polarity, host invasion and pathogenesis.
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Affiliation(s)
- Josh R. Beck
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Connie Fung
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Kurtis W. Straub
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Ajay A. Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - James A. Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Peter J. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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83
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Deponte M, Hoppe HC, Lee MC, Maier AG, Richard D, Rug M, Spielmann T, Przyborski JM. Wherever I may roam: Protein and membrane trafficking in P. falciparum-infected red blood cells. Mol Biochem Parasitol 2012; 186:95-116. [DOI: 10.1016/j.molbiopara.2012.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 11/27/2022]
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84
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Cabrera A, Herrmann S, Warszta D, Santos JM, John Peter AT, Kono M, Debrouver S, Jacobs T, Spielmann T, Ungermann C, Soldati-Favre D, Gilberger TW. Dissection of minimal sequence requirements for rhoptry membrane targeting in the malaria parasite. Traffic 2012; 13:1335-50. [PMID: 22759070 DOI: 10.1111/j.1600-0854.2012.01394.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 06/28/2012] [Accepted: 07/03/2012] [Indexed: 12/20/2022]
Abstract
Rhoptries are specialized secretory organelles characteristic of single cell organisms belonging to the clade Apicomplexa. These organelles play a key role in the invasion process of host cells by accumulating and subsequently secreting an unknown number of proteins mediating host cell entry. Despite their essential role, little is known about their biogenesis, components and targeting determinants. Here, we report on a conserved apicomplexan protein termed Armadillo Repeats-Only (ARO) protein that we localized to the cytosolic face of Plasmodium falciparum and Toxoplasma gondii rhoptries. We show that the first 20 N-terminal amino acids are sufficient for rhoptry membrane targeting. This protein relies on both - myristoylation and palmitoylation motifs - for membrane attachment. Although these lipid modifications are essential, they are not sufficient to direct ARO to the rhoptry membranes. Mutational analysis revealed additional residues within the first 20 amino acids of ARO that play an important role for rhoptry membrane attachment: the positively charged residues R9 and K14. Interestingly, the exchange of R9 with a negative charge entirely abolishes membrane attachment, whereas the exchange of K14 (and to a lesser extent K16) alters only its membrane specificity. Additionally, 17 proteins predicted to be myristoylated and palmitoylated in the first 20 N-terminal amino acids were identified in the genome of the malaria parasite. While most of the corresponding GFP fusion proteins were trafficked to the parasite plasma membrane, two were sorted to the apical organelles. Interestingly, these proteins have a similar motif identified for ARO.
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Affiliation(s)
- Ana Cabrera
- M.G. DeGroote Institute for Infectious Disease Research, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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85
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Sloves PJ, Delhaye S, Mouveaux T, Werkmeister E, Slomianny C, Hovasse A, Dilezitoko Alayi T, Callebaut I, Gaji R, Schaeffer-Reiss C, Van Dorsselear A, Carruthers V, Tomavo S. Toxoplasma Sortilin-like Receptor Regulates Protein Transport and Is Essential for Apical Secretory Organelle Biogenesis and Host Infection. Cell Host Microbe 2012; 11:515-27. [DOI: 10.1016/j.chom.2012.03.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 02/02/2012] [Accepted: 03/28/2012] [Indexed: 12/16/2022]
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86
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Abstract
Infection with the protozoan parasite Toxoplasma gondii is characterized by asymptomatic latent infection in the central nervous system and skeletal muscle tissue in the majority of immunocompentent individuals. Life-threatening reactivation of the infection in immunocompromized patients originates from rupture of Toxoplasma cysts in the brain. While major progress has been made in our understanding of the immunopathogenesis of infection the mechanism(s) of neuroinvasion of the parasite remains poorly understood. The present review presents the current understanding of blood-brain barrier (patho)physiology and the interaction of Toxoplasma gondii with cells of the blood-brain barrier.
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Affiliation(s)
- Sabrina M Feustel
- Institute for Microbiology and Hygiene, Charité Medical School, Berlin, Germany
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87
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Novel N-benzoyl-2-hydroxybenzamide disrupts unique parasite secretory pathway. Antimicrob Agents Chemother 2012; 56:2666-82. [PMID: 22354304 DOI: 10.1128/aac.06450-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that can damage the human brain and eyes. There are no curative medicines. Herein, we describe our discovery of N-benzoyl-2-hydroxybenzamides as a class of compounds effective in the low nanomolar range against T. gondii in vitro and in vivo. Our lead compound, QQ-437, displays robust activity against the parasite and could be useful as a new scaffold for development of novel and improved inhibitors of T. gondii. Our genome-wide investigations reveal a specific mechanism of resistance to N-benzoyl-2-hydroxybenzamides mediated by adaptin-3β, a large protein from the secretory protein complex. N-Benzoyl-2-hydroxybenzamide-resistant clones have alterations of their secretory pathway, which traffics proteins to micronemes, rhoptries, dense granules, and acidocalcisomes/plant-like vacuole (PLVs). N-Benzoyl-2-hydroxybenzamide treatment also alters micronemes, rhoptries, the contents of dense granules, and, most markedly, acidocalcisomes/PLVs. Furthermore, QQ-437 is active against chloroquine-resistant Plasmodium falciparum. Our studies reveal a novel class of compounds that disrupts a unique secretory pathway of T. gondii, with the potential to be used as scaffolds in the search for improved compounds to treat the devastating diseases caused by apicomplexan parasites.
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88
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Anderson-White B, Beck JR, Chen CT, Meissner M, Bradley PJ, Gubbels MJ. Cytoskeleton assembly in Toxoplasma gondii cell division. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 298:1-31. [PMID: 22878103 PMCID: PMC4066374 DOI: 10.1016/b978-0-12-394309-5.00001-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cell division across members of the protozoan parasite phylum Apicomplexa displays a surprising diversity between different species as well as between different life stages of the same parasite. In most cases, infection of a host cell by a single parasite results in the formation of a polyploid cell from which individual daughters bud in a process dependent on a final round of mitosis. Unlike other apicomplexans, Toxoplasma gondii divides by a binary process consisting of internal budding that results in only two daughter cells per round of division. Since T. gondii is experimentally accessible and displays the simplest division mode, it has manifested itself as a model for apicomplexan daughter formation. Here, we review newly emerging insights in the prominent role that assembly of the cortical cytoskeletal scaffold plays in the process of daughter parasite formation.
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Affiliation(s)
| | - Josh R. Beck
- University of California Los Angeles, Department of Microbiology, Immunology and Molecular Genetics, Los Angeles, CA 90095, USA
| | - Chun-Ti Chen
- Boston College, Department of Biology, Chestnut Hill, MA 02467, USA
| | - Markus Meissner
- Division of Infection and Immunity, Institute of Biomedical Life Sciences, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
| | - Peter J. Bradley
- University of California Los Angeles, Department of Microbiology, Immunology and Molecular Genetics, Los Angeles, CA 90095, USA
| | - Marc-Jan Gubbels
- Boston College, Department of Biology, Chestnut Hill, MA 02467, USA
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89
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Limenitakis J, Soldati-Favre D. Functional genetics in Apicomplexa: potentials and limits. FEBS Lett 2011; 585:1579-88. [PMID: 21557944 DOI: 10.1016/j.febslet.2011.05.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 01/15/2023]
Abstract
The Apicomplexans are obligate intracellular protozoan parasites and the causative agents of severe diseases in humans and animals. Although complete genome sequences are available since many years and for several parasites, they are replete with putative genes of unassigned function. Forward and reverse genetic approaches are limited only to a few Apicomplexans that can either be propagated in vitro or in a convenient animal model. This review will compare and contrast the most recent strategies developed for the genetic manipulation of Plasmodium falciparum, Plasmodium berghei and Toxoplasma gondii that have taken advantage of the intrinsic features of their respective genomes. Efforts towards the improvement of the transfection efficiencies in malaria parasites, the development of approaches to study essential genes and the elaboration of high-throughput methods for the identification of gene function will be discussed.
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Affiliation(s)
- Julien Limenitakis
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland.
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90
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Peng HJ, Chen XG, Lindsay DS. A review: Competence, compromise, and concomitance-reaction of the host cell to Toxoplasma gondii infection and development. J Parasitol 2011; 97:620-8. [PMID: 21506833 DOI: 10.1645/ge-2712.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Toxoplasma gondii is an important zoonotic parasite with a worldwide distribution. It infects about one-third of the world's population, causing serious illness in immunosuppressed individuals, fetuses, and infants. Toxoplasma gondii biology within the host cell includes several important phases: (1) active invasion and establishment of a nonfusogenic parasitophorous vacuole in the host cell, (2) extensive modification of the parasitophorous vacuolar membrane for nutrient acquisition, (3) intracellular proliferation by endodyogeny, (4) egress and invasion of new host cells, and (5) stage conversion from tachyzoite to bradyzoite and establishment of chronic infection. During these processes, T. gondii regulates the host cell by modulating morphological, physiological, immunological, genetic, and cellular biological aspects of the host cell. Overall, the infection/development predispositions of T. gondii -host cell interactions overtakes the infection resistance aspects. Upon invasion and development, host cells are modulated to keep a delicate balance between facilitating and eliminating the infection.
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Affiliation(s)
- Hong-Juan Peng
- Department of Etio-biology, School of Public Health and Tropical Medicine, Southern Medical University, 1838 North Guangzhou Rd, Guangzhou, Guangdong Province 510515, People's Republic of China
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91
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Dou Z, Carruthers VB. Cathepsin proteases in Toxoplasma gondii. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 712:49-61. [PMID: 21660658 DOI: 10.1007/978-1-4419-8414-2_4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cysteine proteases are important for the growth and survival of apicomplexan parasites that infect humans. The apicomplexan Toxoplasma gondii expresses five members of the C1 family of cysteine proteases, including one cathepsin L-like (TgCPL), one cathepsin B-like (TgCPB) and three cathepsin C-like (TgCPC1, 2 and 3) proteases. Recent genetic, biochemical and structural studies reveal that cathepsins function in microneme and rhoptry protein maturation, host cell invasion, replication and nutrient acquisition. here, we review the key features and roles of T. gondii cathepsins and discuss the therapeutic potential for specific inhibitor development.
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Affiliation(s)
- Zhicheng Dou
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
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92
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Lemgruber L, Lupetti P, De Souza W, Vommaro RC. New details on the fine structure of the rhoptry of Toxoplasma gondii. Microsc Res Tech 2010; 74:812-8. [DOI: 10.1002/jemt.20960] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 09/29/2010] [Indexed: 11/10/2022]
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93
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Agop-Nersesian C, Egarter S, Langsley G, Foth BJ, Ferguson DJP, Meissner M. Biogenesis of the inner membrane complex is dependent on vesicular transport by the alveolate specific GTPase Rab11B. PLoS Pathog 2010; 6:e1001029. [PMID: 20686666 PMCID: PMC2912401 DOI: 10.1371/journal.ppat.1001029] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 07/02/2010] [Indexed: 01/09/2023] Open
Abstract
Apicomplexan parasites belong to a recently recognised group of protozoa referred to as Alveolata. These protists contain membranous sacs (alveoli) beneath the plasma membrane, termed the Inner Membrane Complex (IMC) in the case of Apicomplexa. During parasite replication the IMC is formed de novo within the mother cell in a process described as internal budding. We hypothesized that an alveolate specific factor is involved in the specific transport of vesicles from the Golgi to the IMC and identified the small GTPase Rab11B as an alveolate specific Rab-GTPase that localises to the growing end of the IMC during replication of Toxoplasma gondii. Conditional interference with Rab11B function leads to a profound defect in IMC biogenesis, indicating that Rab11B is required for the transport of Golgi derived vesicles to the nascent IMC of the daughter cell. Curiously, a block in IMC biogenesis did not affect formation of sub-pellicular microtubules, indicating that IMC biogenesis and formation of sub-pellicular microtubules is not mechanistically linked. We propose a model where Rab11B specifically transports vesicles derived from the Golgi to the immature IMC of the growing daughter parasites.
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Affiliation(s)
- Carolina Agop-Nersesian
- Department of Infectiology, Parasitology, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail: (MM); (CAN)
| | - Saskia Egarter
- Division of Infection & Immunity and Wellcome Centre for Parasitology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Institut Cochin, Inserm, U567, CNRS, UMR 8104, Faculté de Médecine Paris V – Hôpital Cochin, Paris, France
| | - Bernardo J. Foth
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - David J. P. Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, Oxford, United Kingdom
| | - Markus Meissner
- Division of Infection & Immunity and Wellcome Centre for Parasitology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (MM); (CAN)
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94
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Parussini F, Coppens I, Shah PP, Diamond SL, Carruthers VB. Cathepsin L occupies a vacuolar compartment and is a protein maturase within the endo/exocytic system of Toxoplasma gondii. Mol Microbiol 2010; 76:1340-57. [PMID: 20444089 DOI: 10.1111/j.1365-2958.2010.07181.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Regulated exocytosis allows the timely delivery of proteins and other macromolecules precisely when they are needed to fulfil their functions. The intracellular parasite Toxoplasma gondii has one of the most extensive regulated exocytic systems among all unicellular organisms, yet the basis of protein trafficking and proteolytic modification in this system is poorly understood. We demonstrate that a parasite cathepsin protease, TgCPL, occupies a newly recognized vacuolar compartment (VAC) that undergoes dynamic fragmentation during T. gondii replication. We also provide evidence that within the VAC or late endosome this protease mediates the proteolytic maturation of proproteins targeted to micronemes, regulated secretory organelles that deliver adhesive proteins to the parasite surface during cell invasion. Our findings suggest that processing of microneme precursors occurs within intermediate endocytic compartments within the exocytic system, indicating an extensive convergence of the endocytic and exocytic pathways in this human parasite.
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Affiliation(s)
- Fabiola Parussini
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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95
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Plattner H. Membrane Trafficking in Protozoa. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:79-184. [DOI: 10.1016/s1937-6448(10)80003-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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96
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Identification and partial characterization of a dynamin-like protein, EhDLP1, from the protist parasite Entamoeba histolytica. EUKARYOTIC CELL 2009; 9:215-23. [PMID: 19915078 DOI: 10.1128/ec.00214-09] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The dynamin superfamily of proteins includes a large repertoire of evolutionarily conserved GTPases that interact with different subcellular organelle membranes in eukaryotes. Dynamins are thought to participate in a number of cellular processes involving membrane remodeling and scission. Dynamin-like proteins (DLPs) form a subfamily of this vast class and play important roles in cellular processes, such as mitochondrial fission, cytokinesis, and endocytosis. In the present study, a gene encoding a dynamin-like protein (EhDLP1) from the protist parasite Entamoeba histolytica was identified and the protein was partially characterized using a combination of in silico, biochemical, and imaging methods. The protein was capable of GTP binding and hydrolysis, lipid binding, and oligomerization. Immunofluorescence studies showed the protein to be associated with the nuclear membrane. A mutant of EhDLP1 lacking GTP binding and hydrolyzing activities did not associate with the nuclear membrane. The results suggest a nucleus-associated function for EhDLP1.
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van Dooren GG, Reiff SB, Tomova C, Meissner M, Humbel BM, Striepen B. A novel dynamin-related protein has been recruited for apicoplast fission in Toxoplasma gondii. Curr Biol 2009; 19:267-76. [PMID: 19217294 DOI: 10.1016/j.cub.2008.12.048] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 11/18/2008] [Accepted: 12/22/2008] [Indexed: 01/06/2023]
Abstract
BACKGROUND Apicomplexan parasites cause numerous important human diseases, including malaria and toxoplasmosis. Apicomplexa belong to the Alveolata, a group that also includes ciliates and dinoflagellates. Apicomplexa retain a plastid organelle (the apicoplast) that was derived from an endosymbiotic relationship between the alveolate ancestor and a red alga. Apicoplasts are essential for parasite growth and must correctly divide and segregate into daughter cells upon cytokinesis. Apicoplast division depends on association with the mitotic spindle, although little is known about the molecular machinery involved in this process. Apicoplasts lack the conserved machinery that divides chloroplasts in plants and red algae, suggesting that these mechanisms are unique. RESULTS Here, we demonstrate that a dynamin-related protein in Toxoplasma gondii (TgDrpA) localizes to punctate regions on the apicoplast surface. We generate a conditional dominant-negative TgDrpA cell line to disrupt TgDrpA functions and demonstrate that TgDrpA is essential for parasite growth and apicoplast biogenesis. Fluorescence recovery after photobleaching and time-lapse imaging studies provide evidence for a direct role for TgDrpA in apicoplast fission. CONCLUSIONS Our data suggest that DrpA was likely recruited from the alveolate ancestor to function in fission of the symbiont and ultimately replaced the conserved division machinery of that symbiont.
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Affiliation(s)
- Giel G van Dooren
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA
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