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Andrade-Alviárez D, Bonive-Boscan AD, Cáceres AJ, Quiñones W, Gualdrón-López M, Ginger ML, Michels PAM. Delineating transitions during the evolution of specialised peroxisomes: Glycosome formation in kinetoplastid and diplonemid protists. Front Cell Dev Biol 2022; 10:979269. [PMID: 36172271 PMCID: PMC9512073 DOI: 10.3389/fcell.2022.979269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/17/2022] [Indexed: 12/01/2022] Open
Abstract
One peculiarity of protists belonging to classes Kinetoplastea and Diplonemea within the phylum Euglenozoa is compartmentalisation of most glycolytic enzymes within peroxisomes that are hence called glycosomes. This pathway is not sequestered in peroxisomes of the third Euglenozoan class, Euglenida. Previous analysis of well-studied kinetoplastids, the ‘TriTryps’ parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp., identified within glycosomes other metabolic processes usually not present in peroxisomes. In addition, trypanosomatid peroxins, i.e. proteins involved in biogenesis of these organelles, are divergent from human and yeast orthologues. In recent years, genomes, transcriptomes and proteomes for a variety of euglenozoans have become available. Here, we track the possible evolution of glycosomes by querying these databases, as well as the genome of Naegleria gruberi, a non-euglenozoan, which belongs to the same protist supergroup Discoba. We searched for orthologues of TriTryps proteins involved in glycosomal metabolism and biogenesis. Predicted cellular location(s) of each metabolic enzyme identified was inferred from presence or absence of peroxisomal-targeting signals. Combined with a survey of relevant literature, we refine extensively our previously postulated hypothesis about glycosome evolution. The data agree glycolysis was compartmentalised in a common ancestor of the kinetoplastids and diplonemids, yet additionally indicates most other processes found in glycosomes of extant trypanosomatids, but not in peroxisomes of other eukaryotes were either sequestered in this ancestor or shortly after separation of the two lineages. In contrast, peroxin divergence is evident in all euglenozoans. Following their gain of pathway complexity, subsequent evolution of peroxisome/glycosome function is complex. We hypothesize compartmentalisation in glycosomes of glycolytic enzymes, their cofactors and subsequently other metabolic enzymes provided selective advantage to kinetoplastids and diplonemids during their evolution in changing marine environments. We contend two specific properties derived from the ancestral peroxisomes were key: existence of nonselective pores for small solutes and the possibility of high turnover by pexophagy. Critically, such pores and pexophagy are characterised in extant trypanosomatids. Increasing amenability of free-living kinetoplastids and recently isolated diplonemids to experimental study means our hypothesis and interpretation of bioinformatic data are suited to experimental interrogation.
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Affiliation(s)
- Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Alejandro D. Bonive-Boscan
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Ana J. Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | | | - Michael L. Ginger
- School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - Paul A. M. Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Paul A. M. Michels,
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2
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Michels PAM, Gualdrón-López M. Biogenesis and metabolic homeostasis of trypanosomatid glycosomes: new insights and new questions. J Eukaryot Microbiol 2022; 69:e12897. [PMID: 35175680 DOI: 10.1111/jeu.12897] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 11/28/2022]
Abstract
Kinetoplastea and Diplonemea possess peroxisome-related organelles that, uniquely, contain most of the enzymes of the glycolytic pathway and are hence called glycosomes. Enzymes of several other core metabolic pathways have also been located in glycosomes, in addition to some characteristic peroxisomal systems such as pathways of lipid metabolism. A considerable amount of research has been performed on glycosomes of trypanosomes since their discovery four decades ago. Not only the role of the glycosomal enzyme systems in the overall cell metabolism appeared to be unique, but the organelles display also remarkable features regarding their biogenesis and structural properties. These features are similar to those of the well-studied peroxisomes of mammalian and plant cells and yeasts yet exhibit also differences reflecting the large evolutionary distance between these protists and the representatives of other major eukaryotic lineages. Despite all research performed, many questions remain about various properties and the biological roles of glycosomes and peroxisomes. Here we review the current knowledge about glycosomes, often comparing it with information about peroxisomes. Furthermore, we highlight particularly many questions that remain about the biogenesis, and the heterogeneity in structure and content of these enigmatic organelles, and the properties of their boundary membrane.
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Affiliation(s)
- Paul A M Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, The University of Edinburgh, Edinburgh, United Kingdom
| | - Melisa Gualdrón-López
- Instituto Salud Global, Hospital Clinic-Universitat de Barcelona, and Institute for Health Sciences Trias i Pujol, Barcelona, Spain
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3
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Quiñones W, Acosta H, Gonçalves CS, Motta MCM, Gualdrón-López M, Michels PAM. Structure, Properties, and Function of Glycosomes in Trypanosoma cruzi. Front Cell Infect Microbiol 2020; 10:25. [PMID: 32083023 PMCID: PMC7005584 DOI: 10.3389/fcimb.2020.00025] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 01/15/2020] [Indexed: 12/29/2022] Open
Abstract
Glycosomes are peroxisome-related organelles that have been identified in kinetoplastids and diplonemids. The hallmark of glycosomes is their harboring of the majority of the glycolytic enzymes. Our biochemical studies and proteome analysis of Trypanosoma cruzi glycosomes have located, in addition to enzymes of the glycolytic pathway, enzymes of several other metabolic processes in the organelles. These analyses revealed many aspects in common with glycosomes from other trypanosomatids as well as features that seem specific for T. cruzi. Their enzyme content indicates that T. cruzi glycosomes are multifunctional organelles, involved in both several catabolic processes such as glycolysis and anabolic ones. Specifically discussed in this minireview are the cross-talk between glycosomal metabolism and metabolic processes occurring in other cell compartments, and the importance of metabolite translocation systems in the glycosomal membrane to enable the coordination between the spatially separated processes. Possible mechanisms for metabolite translocation across the membrane are suggested by proteins identified in the organelle's membrane-homologs of the ABC and MCF transporter families-and the presence of channels as inferred previously from the detection of channel-forming proteins in glycosomal membrane preparations from the related parasite T. brucei. Together, these data provide insight in the way in which different parts of T. cruzi metabolism, although uniquely distributed over different compartments, are integrated and regulated. Moreover, this information reveals opportunities for the development of drugs against Chagas disease caused by these parasites and for which currently no adequate treatment is available.
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Affiliation(s)
- Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Héctor Acosta
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Camila Silva Gonçalves
- Laboratório de Ultraestrutura Celular Hertha Meyer, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Melisa Gualdrón-López
- Instituto Salud Global, Hospital Clinic-Universitat de Barcelona, and Institute for Health Sciences Trias i Pujol, Barcelona, Spain
| | - Paul A M Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, The University of Edinburgh, Edinburgh, United Kingdom
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Branchini BR, Southworth TL, Fontaine DM, Murtiashaw MH, McGurk A, Talukder MH, Qureshi R, Yetil D, Sundlov JA, Gulick AM. Cloning of the Orange Light-Producing Luciferase from Photinus scintillans-A New Proposal on how Bioluminescence Color is Determined. Photochem Photobiol 2017; 93:479-485. [PMID: 27861940 DOI: 10.1111/php.12671] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/04/2016] [Indexed: 11/29/2022]
Abstract
Unlike the enchanting yellow-green flashes of light produced on warm summer evenings by Photinus pyralis, the most common firefly species in North America, the orange lights of Photinus scintillans are infrequently observed. These Photinus species, and likely all bioluminescent beetles, use the same substrates beetle luciferin, ATP and oxygen to produce light. It is the structure of the particular luciferase enzyme that is the key to determining the color of the emitted light. We report here the molecular cloning of the P. scintillans luc gene and the expression and characterization of the corresponding novel recombinant luciferase enzyme. A comparison of the amino acid sequence with that of the highly similar P. pyralis enzyme and subsequent mutagenesis studies revealed that the single conservative amino acid change tyrosine to phenylalanine at position 255 accounted for the entire emission color difference. Additional mutagenesis and crystallographic studies were performed on a H-bond network, which includes the position 255 residue and five other stringently conserved beetle luciferase residues, that is proximal to the substrate/emitter binding site. The results are interpreted in the context of a speculative proposal that this network is key to the understanding of bioluminescence color determination.
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Affiliation(s)
| | | | | | | | - Alex McGurk
- Department of Chemistry, Connecticut College, New London, CT
| | | | - Rakhshi Qureshi
- Department of Chemistry, Connecticut College, New London, CT
| | - Deniz Yetil
- Department of Chemistry, Connecticut College, New London, CT
| | - Jesse A Sundlov
- Hauptman-Woodward Institute, Buffalo, NY.,Department of Structural Biology, University of Buffalo, Buffalo, NY
| | - Andrew M Gulick
- Hauptman-Woodward Institute, Buffalo, NY.,Department of Structural Biology, University of Buffalo, Buffalo, NY
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Branchini BR, Southworth TL, Salituro LJ, Fontaine DM, Oba Y. Cloning of the Blue Ghost (
Phausis reticulata
) Luciferase Reveals a Glowing Source of Green Light. Photochem Photobiol 2016; 93:473-478. [DOI: 10.1111/php.12649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/31/2016] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | | | - Yuichi Oba
- Department of Environmental Biology College of Bioscience and Biotechnology Chubu University Kasugai Japan
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Cull B, Prado Godinho JL, Fernandes Rodrigues JC, Frank B, Schurigt U, Williams RA, Coombs GH, Mottram JC. Glycosome turnover in Leishmania major is mediated by autophagy. Autophagy 2015; 10:2143-57. [PMID: 25484087 PMCID: PMC4502677 DOI: 10.4161/auto.36438] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Autophagy is a central process behind the cellular remodeling that occurs during differentiation of Leishmania, yet the cargo of the protozoan parasite's autophagosome is unknown. We have identified glycosomes, peroxisome-like organelles that uniquely compartmentalize glycolytic and other metabolic enzymes in Leishmania and other kinetoplastid parasitic protozoa, as autophagosome cargo. It has been proposed that the number of glycosomes and their content change during the Leishmania life cycle as a key adaptation to the different environments encountered. Quantification of RFP-SQL-labeled glycosomes showed that promastigotes of L. major possess ~20 glycosomes per cell, whereas amastigotes contain ~10. Glycosome numbers were significantly greater in promastigotes and amastigotes of autophagy-defective L. major Δatg5 mutants, implicating autophagy in glycosome homeostasis and providing a partial explanation for the previously observed growth and virulence defects of these mutants. Use of GFP-ATG8 to label autophagosomes showed glycosomes to be cargo in ~15% of them; glycosome-containing autophagosomes were trafficked to the lysosome for degradation. The number of autophagosomes increased 10-fold during differentiation, yet the percentage of glycosome-containing autophagosomes remained constant. This indicates that increased turnover of glycosomes was due to an overall increase in autophagy, rather than an upregulation of autophagosomes containing this cargo. Mitophagy of the single mitochondrion was not observed in L. major during normal growth or differentiation; however, mitochondrial remnants resulting from stress-induced fragmentation colocalized with autophagosomes and lysosomes, indicating that autophagy is used to recycle these damaged organelles. These data show that autophagy in Leishmania has a central role not only in maintaining cellular homeostasis and recycling damaged organelles but crucially in the adaptation to environmental change through the turnover of glycosomes.
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Affiliation(s)
- Benjamin Cull
- a Wellcome Trust Center for Molecular Parasitology; Institute of Infection, Immunity and Inflammation; College of Medical, Veterinary and Life Sciences ; University of Glasgow ; Glasgow , UK
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Jamdhade MD, Pawar H, Chavan S, Sathe G, Umasankar PK, Mahale KN, Dixit T, Madugundu AK, Prasad TSK, Gowda H, Pandey A, Patole MS. Comprehensive proteomics analysis of glycosomes from Leishmania donovani. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2015; 19:157-70. [PMID: 25748437 DOI: 10.1089/omi.2014.0163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leishmania donovani is a kinetoplastid protozoan that causes a severe and fatal disease kala-azar, or visceral leishmaniasis. L. donovani infects human host after the phlebotomine sandfly takes a blood meal and resides within the phagolysosome of infected macrophages. Previous studies on host-parasite interactions have not focused on Leishmania organelles and the role that they play in the survival of this parasite within macrophages. Leishmania possess glycosomes that are unique and specialized subcellular microbody organelles. Glycosomes are known to harbor most peroxisomal enzymes and, in addition, they also possess nine glycolytic enzymes. In the present study, we have carried out proteomic profiling using high resolution mass spectrometry of a sucrose density gradient-enriched glycosomal fraction isolated from L. donovani promastigotes. This study resulted in the identification of 4022 unique peptides, leading to the identification of 1355 unique proteins from a preparation enriched in L. donovani glycosomes. Based on protein annotation, 566 (41.8%) were identified as hypothetical proteins with no known function. A majority of the identified proteins are involved in metabolic processes such as carbohydrate, lipid, and nucleic acid metabolism. Our present proteomic analysis is the most comprehensive study to date to map the proteome of L. donovani glycosomes.
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Haanstra JR, González-Marcano EB, Gualdrón-López M, Michels PAM. Biogenesis, maintenance and dynamics of glycosomes in trypanosomatid parasites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1038-48. [PMID: 26384872 DOI: 10.1016/j.bbamcr.2015.09.015] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 12/31/2022]
Abstract
Peroxisomes of organisms belonging to the protist group Kinetoplastea, which include trypanosomatid parasites of the genera Trypanosoma and Leishmania, are unique in playing a crucial role in glycolysis and other parts of intermediary metabolism. They sequester the majority of the glycolytic enzymes and hence are called glycosomes. Their glycosomal enzyme content can vary strongly, particularly quantitatively, between different trypanosomatid species, and within each species during its life cycle. Turnover of glycosomes by autophagy of redundant ones and biogenesis of a new population of organelles play a pivotal role in the efficient adaptation of the glycosomal metabolic repertoire to the sudden, major nutritional changes encountered during the transitions in their life cycle. The overall mechanism of glycosome biogenesis is similar to that of peroxisomes in other organisms, but the homologous peroxins involved display low sequence conservation as well as variations in motifs mediating crucial protein-protein interactions in the process. The correct compartmentalisation of enzymes is essential for the regulation of the trypanosomatids' metabolism and consequently for their viability. For Trypanosoma brucei it was shown that glycosomes also play a crucial role in its life-cycle regulation: a crucial developmental control switch involves the translocation of a protein phosphatase from the cytosol into the organelles. Many glycosomal proteins are differentially phosphorylated in different life-cycle stages, possibly indicative of regulation of enzyme activities as an additional means to adapt the metabolic network to the different environmental conditions encountered.
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Affiliation(s)
- Jurgen R Haanstra
- Systems Bioinformatics, Vrije Universiteit Amsterdam, The Netherlands
| | - Eglys B González-Marcano
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Melisa Gualdrón-López
- Federal University of Minas Gerais, Laboratory of Immunoregulation of Infectious Diseases, Department of Biochemistry and Immunology, Institute for Biological Sciences, Belo Horizonte, Brazil
| | - Paul A M Michels
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela; Centre for Translational and Chemical Biology, Institute of Structural and Molecular Biology, School of Biological Sciences, University of Edinburgh, United Kingdom.
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Van Reet N, Van de Vyver H, Pyana PP, Van der Linden AM, Büscher P. A panel of Trypanosoma brucei strains tagged with blue and red-shifted luciferases for bioluminescent imaging in murine infection models. PLoS Negl Trop Dis 2014; 8:e3054. [PMID: 25144573 PMCID: PMC4140678 DOI: 10.1371/journal.pntd.0003054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/17/2014] [Indexed: 11/19/2022] Open
Abstract
Background Genetic engineering with luciferase reporter genes allows monitoring Trypanosoma brucei (T.b.) infections in mice by in vivo bioluminescence imaging (BLI). Until recently, luminescent T.b. models were based on Renilla luciferase (RLuc) activity. Our study aimed at evaluating red-shifted luciferases for in vivo BLI in a set of diverse T.b. strains of all three subspecies, including some recently isolated from human patients. Methodology/Principal findings We transfected T.b. brucei, T.b. rhodesiense and T.b. gambiense strains with either RLuc, click beetle red (CBR) or Photinus pyralis RE9 (PpyRE9) luciferase and characterised their in vitro luciferase activity, growth profile and drug sensitivity, and their potential for in vivo BLI. Compared to RLuc, the red-shifted luciferases, CBR and PpyRE9, allow tracking of T.b. brucei AnTaR 1 trypanosomes with higher details on tissue distribution, and PpyRE9 allows detection of the parasites with a sensitivity of at least one order of magnitude higher than CBR luciferase. With CBR-tagged T.b. gambiense LiTaR1, T.b. rhodesiense RUMPHI and T.b. gambiense 348 BT in an acute, subacute and chronic infection model respectively, we observed differences in parasite tropism for murine tissues during in vivo BLI. Ex vivo BLI on the brain confirmed central nervous system infection by all luminescent strains of T.b. brucei AnTaR 1, T.b. rhodesiense RUMPHI and T.b. gambiense 348 BT. Conclusions/Significance We established a genetically and phenotypically diverse collection of bioluminescent T.b. brucei, T.b. gambiense and T.b. rhodesiense strains, including drug resistant strains. For in vivo BLI monitoring of murine infections, we recommend trypanosome strains transfected with red-shifted luciferase reporter genes, such as CBR and PpyRE9. Red-shifted luciferases can be detected with a higher sensitivity in vivo and at the same time they improve the spatial resolution of the parasites in the entire body due to the better kinetics of their substrate D-luciferin. Research on African trypanosomes heavily relies on rodent infection models. One way to reduce the number of laboratory rodents used in each experiment and effectively follow the progression of the infection in the same animals is to use genetically modified trypanosomes that allow monitoring of the infection over time with bioluminescence technology, without having to sacrifice the animals at multiple time points. In this study, we were able to establish a collection of bioluminescent strains of all three subspecies of Trypanosoma brucei (T.b.), including T.b. gambiense and T.b. rhodesiense that cause human African trypanosomiasis (HAT) or sleeping sickness. Making use of bioluminescence assays, we demonstrate the diversity of our collection in terms of in vitro and in vivo growth, drug sensitivity and in vivo parasite distribution, including central nervous system tropism. Growth characteristics and drug sensitivity are not affected by the genetic modification with luciferase reporter genes. Trypanosome strains transfected with red-shifted luciferase reporter genes have several advantages compared to the corresponding blue luciferase modified strains. Red light is less absorbed in the blood than blue light, which should lead to higher sensitivity of detection. Furthermore, the substrates that drive the light reaction are better distributed through the body for the red luciferase than for the blue luciferase, which greatly improves spatial resolution of the infection.
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Affiliation(s)
- Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- * E-mail:
| | - Hélène Van de Vyver
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Patient Pati Pyana
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Département de Parasitologie, Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo
| | - Anne Marie Van der Linden
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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Lambrechts D, Roeffaers M, Kerckhofs G, Hofkens J, Van de Putte T, Schrooten J, Van Oosterwyck H. Reporter cell activity within hydrogel constructs quantified from oxygen-independent bioluminescence. Biomaterials 2014; 35:8065-77. [PMID: 24957291 DOI: 10.1016/j.biomaterials.2014.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/01/2014] [Indexed: 12/12/2022]
Abstract
By providing a three-dimensional (3D) support to cells, hydrogels offer a more relevant in vivo tissue-like environment as compared to two-dimensional cell cultures. Hydrogels can be applied as screening platforms to investigate in 3D the role of biochemical and biophysical cues on cell behaviour using bioluminescent reporter cells. Gradients in oxygen concentration that result from the interplay between molecular transport and cell metabolism can however cause substantial variability in the observed bioluminescent reporter cell activity. To assess the influence of these oxygen gradients on the emitted bioluminescence for various hydrogel geometries, a combined experimental and modelling approach was implemented. We show that the applied model is able to predict oxygen gradient independent bioluminescent intensities which correlate better to the experimentally determined viable cell numbers, as compared to the experimentally measured bioluminescent intensities. By analysis of the bioluminescence reaction dynamics we obtained a quantitative description of cellular oxygen metabolism within the hydrogel, which was validated by direct measurements of oxygen concentration within the hydrogel. Bioluminescence peak intensities can therefore be used as a quantitative measurement of reporter cell activity within a hydrogel, but an unambiguous interpretation of these intensities requires a compensation for the influence of cell-induced oxygen gradients on the luciferase activity.
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Affiliation(s)
- Dennis Lambrechts
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 - Box 2450, 3001 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering Leuven, KU Leuven, Herestraat 49 - Box 813, 3000 Leuven, Belgium
| | - Maarten Roeffaers
- Center for Surface Chemistry and Catalysis, KU Leuven, Kasteelpark Arenberg 23, 3001 Leuven, Belgium
| | - Greet Kerckhofs
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 - Box 2450, 3001 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering Leuven, KU Leuven, Herestraat 49 - Box 813, 3000 Leuven, Belgium
| | - Johan Hofkens
- Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Tom Van de Putte
- TiGenix NV, Haasrode Researchpark 1724, Romeinse Straat 12 box 2, 3001 Leuven, Belgium
| | - Jan Schrooten
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 - Box 2450, 3001 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering Leuven, KU Leuven, Herestraat 49 - Box 813, 3000 Leuven, Belgium.
| | - Hans Van Oosterwyck
- Prometheus, Division of Skeletal Tissue Engineering Leuven, KU Leuven, Herestraat 49 - Box 813, 3000 Leuven, Belgium; Biomechanics Section, KU Leuven, Celestijnenlaan 300C - Box 2419, 3001 Leuven, Belgium.
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11
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Analysis of the Leishmania peroxin 7 interactions with peroxin 5, peroxin 14 and PTS2 ligands. Biochem J 2014; 460:273-82. [DOI: 10.1042/bj20131628] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
LPEX7 (Leishmania peroxin 7) is essential for targeting newly synthesized proteins with a PTS2 (peroxisome-targeting signal type 2) import signal into the glycosome. In the present paper, we describe the biophysical characterization of a functional LPEX7 isolated from Escherichia coli inclusion bodies. Pull-down assays showed that LPEX7 binds the interacting partners LdPEX5 (Leishmania donovani peroxin 5) and LdPEX14, but, more importantly, this receptor can specifically bind PTS2 cargo proteins in the monomeric and dimeric states. However, in the absence of interacting partners, LPEX7 preferentially adopts a tetrameric structure. Mapping studies localized the LdPEX5- and LdPEX14-binding sites to the N-terminal portion of LPEX7. Deletion of the first 52 residues abolished LdPEX14 association without altering the LdPEX5 interaction. Intrinsic fluorescence techniques suggested that each LPEX7 subunit has a single unique binding site for each of the respective interacting partners LdPEX5, LdPEX14 and PTS2 cargo proteins. Extrinsic fluorescence studies with ANS (8-anilinonaphthalene-1-sulfonic acid) demonstrated that LPEX7 contains a surface-exposed hydrophobic region(s) that was not altered by the binding of a PTS2 protein or LdPEX5. However, in the presence of these ligands, the accessibility of the hydrophobic domain was dramatically restricted, suggesting that both ligands are necessary to induce notable conformational changes in LPEX7. In contrast, binding of LdPEX14 did not alter the hydrophobic domain on LPEX7. It is possible that the hydrophobic surfaces on LPEX7 may be a crucial characteristic for the shuttling of this receptor in and out of the glycosome.
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Fernández-Moya SM, Carrington M, Estévez AM. A short RNA stem-loop is necessary and sufficient for repression of gene expression during early logarithmic phase in trypanosomes. Nucleic Acids Res 2014; 42:7201-9. [PMID: 24813448 PMCID: PMC4066783 DOI: 10.1093/nar/gku358] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have compared the transcriptomes of cultured procyclic Trypanosoma brucei cells in early and late logarithmic phases and found that ∼200 mRNAs were differentially regulated. In late log phase cells, the most upregulated mRNA encoded the nucleobase transporter NT8. The 3' untranslated region (UTR) of NT8 contains a short stem-loop cis-element that is necessary for the regulation of NT8 expression in response to external purine levels. When placed in the 3'-UTR of an unregulated transcript, the cis-element is sufficient to confer regulation in response to purines. To our knowledge, this is the first example of a discrete RNA element that can autonomously regulate gene expression in trypanosomes in response to an external factor and reveals an unprecedented purine-dependent signaling pathway that controls gene expression in eukaryotes.
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Affiliation(s)
- Sandra M Fernández-Moya
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento, s/n, 18016 Armilla, Granada, Spain
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Antonio M Estévez
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento, s/n, 18016 Armilla, Granada, Spain
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13
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Santos-Gomes GM, Rodrigues A, Teixeira F, Carreira J, Alexandre-Pires G, Carvalho S, Santos-Mateus D, Martins C, Vale-Gato I, Marques C, Tomás AM. Immunization with the Leishmania infantum recombinant cyclophilin protein 1 confers partial protection to subsequent parasite infection and generates specific memory T cells. Vaccine 2014; 32:1247-53. [PMID: 24486368 DOI: 10.1016/j.vaccine.2014.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/13/2013] [Accepted: 01/14/2014] [Indexed: 12/15/2022]
Abstract
Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These drugs present high toxicity and require longer treatment regimens which complicate compliance to the treatment. Other control measures directed to the vector or the reservoirs are useful tools to restrain the spreading of this disease but the effects are transitory. A safe, affordable and efficient vaccine conferring long lasting immunity should be the most cost effective way of controlling zoonotic visceral leishmaniosis. The present study aims at characterizing a cyclophilin protein 1 of Leishmania infantum (LiCyP1) and investigating whether recombinant LiCyP1 (LirCyP1) is able to confer protection against infection by evaluating viable parasite load and the generation of specific CD4(+) and CD8(+) effector and central memory T cells in rodent model. LiCyP1 is present in the cytoplasm of L. infantum amastigotes and promastigotes. Immunization of BALB/c mice with LirCyP1 confers high protection to L. infantum infection, causing a marked reduction in parasite replication in the liver and spleen. Furthermore, helper and cytotoxic memory T cell subsets able to specifically recognize parasite antigens expanded in immunized and in challenged mice. CD4(+) T cell subpopulation of intermediate phenotype (CD62L(high)CD127(low)) of challenging mice also presented an accentuated expansion after the recall. This study demonstrated that LirCyP1 confers partial protection to L. infantum infection, promoting the generation of a desired long lasting immunity. LirCyP1 can be considered a potential candidate for the design of a vaccine against zoonotic visceral leishmaniosis.
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Affiliation(s)
- G M Santos-Gomes
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal.
| | - A Rodrigues
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
| | - F Teixeira
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto, Portugal
| | - J Carreira
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto, Portugal
| | - G Alexandre-Pires
- CIISA, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Av. Universidade Técnica, 1300-477 Lisboa, Portugal
| | - S Carvalho
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto, Portugal
| | - D Santos-Mateus
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
| | - C Martins
- Departamento de Imunologia, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires de Pátria, Lisboa, Portugal
| | - I Vale-Gato
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
| | - C Marques
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
| | - A M Tomás
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto, Portugal
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14
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Myburgh E, Coles JA, Ritchie R, Kennedy PGE, McLatchie AP, Rodgers J, Taylor MC, Barrett MP, Brewer JM, Mottram JC. In vivo imaging of trypanosome-brain interactions and development of a rapid screening test for drugs against CNS stage trypanosomiasis. PLoS Negl Trop Dis 2013; 7:e2384. [PMID: 23991236 PMCID: PMC3749981 DOI: 10.1371/journal.pntd.0002384] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/13/2013] [Indexed: 11/18/2022] Open
Abstract
HUMAN AFRICAN TRYPANOSOMIASIS (HAT) MANIFESTS IN TWO STAGES OF DISEASE: firstly, haemolymphatic, and secondly, an encephalitic phase involving the central nervous system (CNS). New drugs to treat the second-stage disease are urgently needed, yet testing of novel drug candidates is a slow process because the established animal model relies on detecting parasitemia in the blood as late as 180 days after treatment. To expedite compound screening, we have modified the GVR35 strain of Trypanosoma brucei brucei to express luciferase, and have monitored parasite distribution in infected mice following treatment with trypanocidal compounds using serial, non-invasive, bioluminescence imaging. Parasites were detected in the brains of infected mice following treatment with diminazene, a drug which cures stage 1 but not stage 2 disease. Intravital multi-photon microscopy revealed that trypanosomes enter the brain meninges as early as day 5 post-infection but can be killed by diminazene, whereas those that cross the blood-brain barrier and enter the parenchyma by day 21 survived treatment and later caused bloodstream recrudescence. In contrast, all bioluminescent parasites were permanently eliminated by treatment with melarsoprol and DB829, compounds known to cure stage 2 disease. We show that this use of imaging reduces by two thirds the time taken to assess drug efficacy and provides a dual-modal imaging platform for monitoring trypanosome infection in different areas of the brain.
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Affiliation(s)
- Elmarie Myburgh
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jonathan A. Coles
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ryan Ritchie
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Peter G. E. Kennedy
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alex P. McLatchie
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jean Rodgers
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Martin C. Taylor
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael P. Barrett
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
| | - James M. Brewer
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jeremy C. Mottram
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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15
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Goyard S, Dutra PL, Deolindo P, Autheman D, D'Archivio S, Minoprio P. In vivo imaging of trypanosomes for a better assessment of host-parasite relationships and drug efficacy. Parasitol Int 2013; 63:260-8. [PMID: 23892180 DOI: 10.1016/j.parint.2013.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 05/20/2013] [Accepted: 07/16/2013] [Indexed: 11/19/2022]
Abstract
The advances in microscopy combined to the invaluable progress carried by the utilization of molecular, immunological or immunochemical markers and the implementation of more powerful imaging technologies have yielded great improvements to the knowledge of the interaction between microorganisms and their hosts, notably a better understanding of the establishment of infectious processes. Still today, the intricacies of the dialog between parasites, cells and tissues remain limited. Some improvements have been attained with the stable integration and expression of the green fluorescence protein or firefly luciferase and other reporter genes, which have allowed to better approach the monitoring of gene expression and protein localization in vivo, in situ and in real time. Aiming at better exploring the well-established models of murine infections with the characterized strains of Trypanosoma cruzi and Trypanosoma vivax, we revisited in the present report the state of the art about the tools for the imaging of Trypanosomatids in vitro and in vivo and show the latest transgenic parasites that we have engineered in our laboratory using conventional transfection methods. The targeting of trypanosomes presented in this study is a promising tool for approaching the biology of parasite interactions with host cells, the progression of the diseases they trigger and the screening of new drugs in vivo or in vitro.
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Affiliation(s)
- S Goyard
- Institut Pasteur, Laboratoire des Processus Infectieux à Trypanosomatidés, Département Infection et Epidemiologie, 25 rue du Dr. Roux, 75724 Paris, France
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16
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Verplaetse E, Gualdrón-López M, Chevalier N, Michels PAM. Studies on the organization of the docking complex involved in matrix protein import into glycosomes of Trypanosoma brucei. Biochem Biophys Res Commun 2012; 424:781-5. [PMID: 22809509 DOI: 10.1016/j.bbrc.2012.07.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022]
Abstract
Trypanosoma brucei contains peroxisome-like organelles designated glycosomes because they sequester the major part of the glycolytic pathway. Import of proteins into the peroxisomal matrix involves a protein complex associated with the peroxisomal membrane of which PEX13 is a component. Two very different PEX13 isoforms have recently been identified in T. brucei. A striking feature of one of the isoforms, TbPEX13.1, is the presence of a C-terminal type 1 peroxisomal-targeting signal (PTS1), the tripeptide TKL, conserved in its orthologues in all members of the Trypanosomatidae family so far studied, but absent from TbPEX13.2 and the PEX13s in all other organisms. Despite their differences, both TbPEX13s function as part of a docking complex for cytosolic receptors with bound matrix proteins to be imported. We further characterized TbPEX13.1's function in glycosomal matrix-protein import. It provides a frame to anchor another docking complex component, PEX14, to the glycosomal membrane or information to correctly position it within the membrane. To investigate the possible function of the C-terminal TKL, we determined the topology of the C-terminal half of TbPEX13.1 in the membrane and show that its SH3 domain, located immediately adjacent to the PTS1, is at the cytosolic face.
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Affiliation(s)
- Emilie Verplaetse
- Research Unit for Tropical Diseases, de Duve Institute, Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
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17
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Wilson ZN, Gilroy CA, Boitz JM, Ullman B, Yates PA. Genetic dissection of pyrimidine biosynthesis and salvage in Leishmania donovani. J Biol Chem 2012; 287:12759-70. [PMID: 22367196 DOI: 10.1074/jbc.m112.346502] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protozoan parasites of the Leishmania genus express the metabolic machinery to synthesize pyrimidine nucleotides via both de novo and salvage pathways. To evaluate the relative contributions of pyrimidine biosynthesis and salvage to pyrimidine homeostasis in both life cycle stages of Leishmania donovani, individual mutant lines deficient in either carbamoyl phosphate synthetase (CPS), the first enzyme in pyrimidine biosynthesis, uracil phosphoribosyltransferase (UPRT), a salvage enzyme, or both CPS and UPRT were constructed. The Δcps lesion conferred pyrimidine auxotrophy and a growth requirement for medium supplementation with one of a plethora of pyrimidine nucleosides or nucleobases, although only dihydroorotate or orotate could circumvent the pyrimidine auxotrophy of the Δcps/Δuprt double knockout. The Δuprt null mutant was prototrophic for pyrimidines but could not salvage uracil or any pyrimidine nucleoside. The capability of the Δcps parasites to infect mice was somewhat diminished but still robust, indicating active pyrimidine salvage by the amastigote form of the parasite, but the Δcps/Δuprt mutant was completely attenuated with no persistent parasites detected after a 4-week infection. Complementation of the Δcps/Δuprt clone with either CPS or UPRT restored infectivity. These data establish that an intact pyrimidine biosynthesis pathway is essential for the growth of the promastigote form of L. donovani in culture, that all uracil and pyrimidine nucleoside salvage in the parasite is mediated by UPRT, and that both the biosynthetic and salvage pathways contribute to a robust infection of the mammalian host by the amastigote. These findings impact potential therapeutic design and vaccine strategies for visceral leishmaniasis.
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Affiliation(s)
- Zachary N Wilson
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239, USA
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18
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Al-Ani GK, Patel N, Pirani KA, Zhu T, Dhalladoo S, Zufferey R. The N-terminal domain and glycosomal localization of Leishmania initial acyltransferase LmDAT are important for lipophosphoglycan synthesis. PLoS One 2011; 6:e27802. [PMID: 22114698 PMCID: PMC3219689 DOI: 10.1371/journal.pone.0027802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 10/25/2011] [Indexed: 11/18/2022] Open
Abstract
Ether glycerolipids of Leishmania major are important membrane components as well as building blocks of various virulence factors. In L. major, the first enzyme of the ether glycerolipid biosynthetic pathway, LmDAT, is an unusual, glycosomal dihydroxyacetonephosphate acyltransferase important for parasite's growth and survival during the stationary phase, synthesis of ether lipids, and virulence. The present work extends our knowledge of this important biosynthetic enzyme in parasite biology. Site-directed mutagenesis of LmDAT demonstrated that an active enzyme was critical for normal growth and survival during the stationary phase. Deletion analyses showed that the large N-terminal extension of this initial acyltransferase may be important for its stability or activity. Further, abrogation of the C-terminal glycosomal targeting signal sequence of LmDAT led to extraglycosomal localization, did not impair its enzymatic activity but affected synthesis of the ether glycerolipid-based virulence factor lipophosphoglycan. In addition, expression of this recombinant form of LmDAT in a null mutant of LmDAT did not restore normal growth and survival during the stationary phase. These results emphasize the importance of this enzyme's compartmentalization in the glycosome for the generation of lipophosphoglycan and parasite's biology.
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Affiliation(s)
- Gada K. Al-Ani
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, United States of America
| | - Nipul Patel
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
| | - Karim A. Pirani
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, United States of America
| | - Tongtong Zhu
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
| | - Subbhalakshmi Dhalladoo
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
| | - Rachel Zufferey
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, United States of America
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
- * E-mail:
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19
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The characterization and evolutionary relationships of a trypanosomal thiolase. Int J Parasitol 2011; 41:1273-83. [DOI: 10.1016/j.ijpara.2011.07.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/22/2011] [Accepted: 07/19/2011] [Indexed: 11/23/2022]
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20
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Role of thiamine pyrophosphate in oligomerisation, functioning and import of peroxisomal 2-hydroxyacyl-CoA lyase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1226-33. [PMID: 21708296 DOI: 10.1016/j.bbapap.2011.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 05/26/2011] [Accepted: 06/10/2011] [Indexed: 11/20/2022]
Abstract
During peroxisomal α-oxidation, the CoA-esters of phytanic acid and 2-hydroxylated straight chain fatty acids are cleaved into a (n-1) fatty aldehyde and formyl-CoA by 2-hydroxyacyl-CoA lyase (HACL1). HACL1 is imported into peroxisomes via the PEX5/PTS1 pathway, and so far, it is the only known peroxisomal TPP-dependent enzyme in mammals. In this study, the effect of mutations in the TPP-binding domain of HACL1 on enzyme activity, subcellular localisation and oligomerisation was investigated. Mutations of the aspartate 455 and serine 456 residues within the TPP binding domain of the human HACL1 did not affect the targeting upon expression in transfected CHO cells, although enzyme activity was abolished. Gel filtration of native and mutated N-His(6)-fusions, expressed in yeast, revealed that the mutations did not influence the oligomerisation of the (apo)enzyme. Subcellular fractionation of yeast cells expressing HACL1 showed that the lyase activity sedimented at high density in a Nycodenz gradient. In these fractions TPP could be measured, but not when mutated HACL1 was expressed, although the recombinant enzyme was still targeted to peroxisomes. These findings indicate that the binding of TPP is not required for peroxisomal targeting and correct folding of HACL1, in contrast to other TPP-dependent enzymes, and suggest that transport of TPP into peroxisomes is dependent on HACL1 import, without requirement of a specific solute transporter.
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21
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French JB, Yates PA, Soysa DR, Boitz JM, Carter NS, Chang B, Ullman B, Ealick SE. The Leishmania donovani UMP synthase is essential for promastigote viability and has an unusual tetrameric structure that exhibits substrate-controlled oligomerization. J Biol Chem 2011; 286:20930-41. [PMID: 21507942 PMCID: PMC3121495 DOI: 10.1074/jbc.m111.228213] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/30/2011] [Indexed: 11/06/2022] Open
Abstract
The final two steps of de novo uridine 5'-monophosphate (UMP) biosynthesis are catalyzed by orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC). In most prokaryotes and simple eukaryotes these two enzymes are encoded by separate genes, whereas in mammals they are expressed as a bifunctional gene product called UMP synthase (UMPS), with OPRT at the N terminus and OMPDC at the C terminus. Leishmania and some closely related organisms also express a bifunctional enzyme for these two steps, but the domain order is reversed relative to mammalian UMPS. In this work we demonstrate that L. donovani UMPS (LdUMPS) is an essential enzyme in promastigotes and that it is sequestered in the parasite glycosome. We also present the crystal structure of the LdUMPS in complex with its product, UMP. This structure reveals an unusual tetramer with two head to head and two tail to tail interactions, resulting in two dimeric OMPDC and two dimeric OPRT functional domains. In addition, we provide structural and biochemical evidence that oligomerization of LdUMPS is controlled by product binding at the OPRT active site. We propose a model for the assembly of the catalytically relevant LdUMPS tetramer and discuss the implications for the structure of mammalian UMPS.
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Affiliation(s)
- Jarrod B. French
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 and
| | - Phillip A. Yates
- the Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239
| | - D. Radika Soysa
- the Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239
| | - Jan M. Boitz
- the Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239
| | - Nicola S. Carter
- the Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239
| | - Bailey Chang
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 and
| | - Buddy Ullman
- the Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239
| | - Steven E. Ealick
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 and
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22
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Nazari M, Hosseinkhani S. Design of disulfide bridge as an alternative mechanism for color shift in firefly luciferase and development of secreted luciferase. Photochem Photobiol Sci 2011; 10:1203-15. [DOI: 10.1039/c1pp05012e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Matre P, Meyer C, Lillo C. Diversity in subcellular targeting of the PP2A B'eta subfamily members. PLANTA 2009; 230:935-45. [PMID: 19672620 DOI: 10.1007/s00425-009-0998-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 07/22/2009] [Indexed: 05/20/2023]
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine-specific phosphatase comprising a catalytic subunit (C), a scaffolding subunit (A), and a regulatory subunit (B). The B subunits are believed to be responsible for substrate specificity and localization of the PP2A complex. In plants, three families of B subunits exist, i.e. B (B55), B', and B''. Here, we report differential subcellular targeting within the Arabidopsis B'eta subfamily, which consists of the close homologs B'eta, B'theta, B'gamma and B'zeta. Phenotypes of corresponding knockouts were observed, and particularly revealed delayed flowering for the B'eta knockout. The B' subunits were linked to fluorescent tags and transiently expressed in various tissues of onion, tobacco and Arabidopsis. B'eta and B'gamma targeted the cytosol and nucleus. B'zeta localized to the cytoplasm and partly co-localized with mitochondrial markers when the N-terminus was free. Provided its C-terminus was free, the B'theta subunit targeted peroxisomes. The importance of the C-terminal end for peroxisomal targeting was further confirmed by truncation of the C-terminus. The results revealed that the closely related B' subunits are targeting different organelles in plants, and exemplify the usage of the peptide serine-serine-leucine as a PTS1 peroxisomal signaling peptide.
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Affiliation(s)
- Polina Matre
- Faculty of Science and Technology, University of Stavanger, Centre for Organelle Research, 4036 Stavanger, Norway
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24
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Dube A, Gupta R, Singh N. Reporter genes facilitating discovery of drugs targeting protozoan parasites. Trends Parasitol 2009; 25:432-9. [PMID: 19720564 DOI: 10.1016/j.pt.2009.06.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 03/24/2009] [Accepted: 06/22/2009] [Indexed: 02/03/2023]
Abstract
Transfection of protozoan parasites, such as Plasmodium, Leishmania, Trypanosoma and Toxoplasma, with various reporter gene constructs, has revolutionized studies to understand the biology of the host-parasite interactions at the cellular level. It has provided impetus to the development of rapid and reliable drug screens both for established drugs and for new molecules against different parasites and other pathogens. Furthermore, reporter genes have proved to be an excellent and promising tool for studying disease progression. Here, we review the recent advances made by using reporter genes for in vitro and in vivo drug screening, high-throughput screening, whole-animal non-invasive imaging for parasites and for the study of several aspects of host-parasite interactions.
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Affiliation(s)
- Anuradha Dube
- Division of Parasitology, Central Drug Research Institute, Lucknow 226 001, India.
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Claes F, Vodnala SK, van Reet N, Boucher N, Lunden-Miguel H, Baltz T, Goddeeris BM, Büscher P, Rottenberg ME. Bioluminescent imaging of Trypanosoma brucei shows preferential testis dissemination which may hamper drug efficacy in sleeping sickness. PLoS Negl Trop Dis 2009; 3:e486. [PMID: 19621071 PMCID: PMC2707598 DOI: 10.1371/journal.pntd.0000486] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 06/16/2009] [Indexed: 11/18/2022] Open
Abstract
Monitoring Trypanosoma spread using real-time imaging in vivo provides a fast method to evaluate parasite distribution especially in immunoprivileged locations. Here, we generated monomorphic and pleomorphic recombinant Trypanosoma brucei expressing the Renilla luciferase. In vitro luciferase activity measurements confirmed the uptake of the coelenterazine substrate by live parasites and light emission. We further validated the use of Renilla luciferase-tagged trypanosomes for real-time bioluminescent in vivo analysis. Interestingly, a preferential testis tropism was observed with both the monomorphic and pleomorphic recombinants. This is of importance when considering trypanocidal drug development, since parasites might be protected from many drugs by the blood-testis barrier. This hypothesis was supported by our final study of the efficacy of treatment with trypanocidal drugs in T. brucei-infected mice. We showed that parasites located in the testis, as compared to those located in the abdominal cavity, were not readily cleared by the drugs.
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Affiliation(s)
- Filip Claes
- Institute of Tropical Medicine Antwerp, Department of Parasitology, Antwerp, Belgium.
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26
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Jetton N, Rothberg KG, Hubbard JG, Wise J, Li Y, Ball HL, Ruben L. The cell cycle as a therapeutic target against Trypanosoma brucei: Hesperadin inhibits Aurora kinase-1 and blocks mitotic progression in bloodstream forms. Mol Microbiol 2009; 72:442-58. [PMID: 19320832 DOI: 10.1111/j.1365-2958.2009.06657.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aurora kinase family members co-ordinate a range of events associated with mitosis and cytokinesis. Anti-cancer therapies are currently being developed against them. Here, we evaluate whether Aurora kinase-1 (TbAUK1) from pathogenic Trypanosoma brucei might be targeted in anti-parasitic therapies as well. Conditional knockdown of TbAUK1 within infected mice demonstrated its essential contribution to infection. An in vitro kinase assay was developed which used recombinant trypanosome histone H3 as a substrate. Tandem mass spectroscopy identified a novel phosphorylation site in the carboxyl-tail of recombinant trypanosome histone H3. Hesperadin, an inhibitor of human Aurora B, prevented the phosphorylation of substrate with IC(50) of 40 nM. Growth of cultured bloodstream forms was also sensitive to Hesperadin (IC(50) of 50 nM). Hesperadin blocked nuclear division and cytokinesis but not other aspects of the cell cycle. Consequently, growth arrested cells accumulated multiple kinetoplasts, flagella and nucleoli, similar to the effects of RNAi-dependent knockdown of TbAUK1 in cultured bloodstream forms cells. Molecular models predicted high-affinity binding of Hesperadin to both conserved and novel sites in TbAUK1. Collectively, these data demonstrate that cell cycle progression is essential for infections with T. brucei and that parasite Aurora kinases can be targeted with small-molecule inhibitors.
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Affiliation(s)
- Neal Jetton
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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27
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Regmi S, Rothberg KG, Hubbard JG, Ruben L. The RACK1 signal anchor protein from Trypanosoma brucei associates with eukaryotic elongation factor 1A: a role for translational control in cytokinesis. Mol Microbiol 2008; 70:724-45. [PMID: 18786142 PMCID: PMC2581647 DOI: 10.1111/j.1365-2958.2008.06443.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
RACK1 is a WD-repeat protein that forms signal complexes at appropriate locations in the cell. RACK1 homologues are core components of ribosomes from yeast, plants and mammals. In contrast, a cryo-EM analysis of trypanosome ribosomes failed to detect RACK1, thus eliminating an important translational regulatory mechanism. Here we report that TbRACK1 from Trypanosoma brucei associates with eukaryotic translation elongation factor-1a (eEF1A) as determined by tandem MS of TAP-TbRACK1 affinity eluates, co-sedimentation in a sucrose gradient, and co-precipitation assays. Consistent with these observations, sucrose gradient purified 80S monosomes and translating polysomes each contained TbRACK1. When RNAi was used to deplete cells of TbRACK1, a shift in the polysome profile was observed, while the phosphorylation of a ribosomal protein increased. Under these conditions, cell growth became hypersensitive to the translational inhibitor anisomycin. The kinetoplasts and nuclei were misaligned in the postmitotic cells, resulting in partial cleavage furrow ingression during cytokinesis. Overall, these findings identify eEF1A as a novel TbRACK1 binding partner and establish TbRACK1 as a component of the trypanosome translational apparatus. The synergy between anisomycin and TbRACK1 RNAi suggests that continued translation is required for complete ingression of the cleavage furrow.
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Affiliation(s)
- Sandesh Regmi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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28
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Estévez AM. The RNA-binding protein TbDRBD3 regulates the stability of a specific subset of mRNAs in trypanosomes. Nucleic Acids Res 2008; 36:4573-86. [PMID: 18611951 PMCID: PMC2504296 DOI: 10.1093/nar/gkn406] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In trypanosomes, the apparent lack of regulation of RNA polymerase II-dependent transcription initiation poses a challenge to understand how these eukaryotes adjust gene expression to adapt to the contrasting environments they find during their life cycles. Evidence so far indicates that mRNA turnover and translation are the major control points in which regulation is exerted in trypanosomes. However, very little is known about which proteins are involved, and how do they regulate the abundance and translation of different mRNAs in different life stages. In this work, an RNA-binding protein, TbDRBD3, has been identified by affinity chromatography, and its function addressed using RNA interference, microarray analysis and immunoprecipitation of mRNA-protein complexes. The results obtained indicate that TbDRBD3 binds to a subset of developmentally regulated mRNAs encoding membrane proteins, and that this association promotes the stabilization of the target transcripts. These observations raise the possibility that TbDRBD3-mRNA complexes act as a post-transcriptional operon, and provide a framework to interpret how trypanosomes regulate gene expression in the absence of transcriptional control.
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Affiliation(s)
- Antonio M Estévez
- Instituto de Parasitología y Biomedicina López-Neyra, CSIC Avda. del Conocimiento s/n, Armilla, 18100-Granada, Spain.
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29
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Traba J, Froschauer EM, Wiesenberger G, Satrústegui J, Del Arco A. Yeast mitochondria import ATP through the calcium-dependent ATP-Mg/Pi carrier Sal1p, and are ATP consumers during aerobic growth in glucose. Mol Microbiol 2008; 69:570-85. [PMID: 18485069 DOI: 10.1111/j.1365-2958.2008.06300.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sal1p, a novel Ca2+-dependent ATP-Mg/Pi carrier, is essential in yeast lacking all adenine nucleotide translocases. By targeting luciferase to the mitochondrial matrix to monitor mitochondrial ATP levels, we show in isolated mitochondria that both ATP-Mg and free ADP are taken up by Sal1p with a K(m) of 0.20 +/- 0.03 mM and 0.28 +/- 0.06 mM respectively. Nucleotide transport along Sal1p is strictly Ca2+ dependent. Ca2+ increases the V(max) with a S(0.5) of 15 muM, and no changes in the K(m) for ATP-Mg. Glucose sensing in yeast generates Ca2+ transients involving Ca2+ influx from the external medium. We find that carbon-deprived cells respond to glucose with an immediate increase in mitochondrial ATP levels which is not observed in the presence of EGTA or in Sal1p-deficient cells. Moreover, we now report that during normal aerobic growth on glucose, yeast mitochondria import ATP from the cytosol and hydrolyse it through H+-ATP synthase. We identify two pathways for ATP uptake in mitochondria, the ADP/ATP carriers and Sal1p. Thus, during exponential growth on glucose, mitochondria are ATP consumers, as those from cells growing in anaerobic conditions or deprived of mitochondrial DNA which depend on cytosolic ATP and mitochondrial ATPase working in reverse to generate a mitochondrial membrane potential. In conclusion, the results show that growth on glucose requires ATP hydrolysis in mitochondria and recruits Sal1p as a Ca2+-dependent mechanism to import ATP-Mg from the cytosol. Whether this mechanism is used under similar settings in higher eukaryotes is an open question.
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Affiliation(s)
- Javier Traba
- Departamento de Biologia Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma, Madrid, Spain
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30
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Grzmil P, Burfeind C, Preuss T, Dixkens C, Wolf S, Engel W, Burfeind P. The putative peroxisomal gene Pxt1 is exclusively expressed in the testis. Cytogenet Genome Res 2007; 119:74-82. [PMID: 18160785 DOI: 10.1159/000109622] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 06/18/2007] [Indexed: 01/18/2023] Open
Abstract
Genes reported to be crucial for spermatogenesis are often exclusively expressed in the testis. We have identified a novel male germ cell-specific expressed gene named peroxisomal testis specific 1 (Pxt1) with expression starting at the spermatocyte stage during mouse spermatogenesis. The putative amino acid sequence encoded by the cDNA of the Pxt1 gene contains a conserved Asn-His-Leu (NHL)-motif at its C-terminal end, which is characteristic for peroxisomal proteins. Pxt1-EGFP fusion protein is co-localized with known peroxisomal marker proteins in transfected NIH3T3 cells. In addition, we could demonstrate that the peroxisomal targeting signal NHL is functional and responsible for the correct subcellular localization of the Pxt1-EGFP fusion protein. In male germ cells peroxisomes were reported only in spermatogonia. The Pxt1 gene is so far the first gene coding for a putative peroxisomal protein which is expressed in later steps of spermatogenesis, namely in pachytene spermatocytes.
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Affiliation(s)
- P Grzmil
- Institute of Human Genetics, University of Göttingen, Germany
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31
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Saveria T, Halbach A, Erdmann R, Volkmer-Engert R, Landgraf C, Rottensteiner H, Parsons M. Conservation of PEX19-binding motifs required for protein targeting to mammalian peroxisomal and trypanosome glycosomal membranes. EUKARYOTIC CELL 2007; 6:1439-49. [PMID: 17586720 PMCID: PMC1951143 DOI: 10.1128/ec.00084-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glycosomes are divergent peroxisomes found in trypanosomatid protozoa, including those that cause severe human diseases throughout much of the world. While peroxisomes are dispensable for both yeast (Saccharomyces cerevisiae and others) and mammalian cells in vitro, glycosomes are essential for trypanosomes and hence are viewed as a potential drug target. The import of proteins into the matrix of peroxisomes utilizes multiple peroxisomal membrane proteins which require the peroxin PEX19 for insertion into the peroxisomal membrane. In this report, we show that the specificity of peroxisomal membrane protein binding for Trypanosoma brucei PEX19 is very similar to those previously identified for human and yeast PEX19. Our studies show that trafficking is conserved across these distant phyla and that both a PEX19 binding site and a transmembrane domain are required for the insertion of two test proteins into the glycosomal membrane. However, in contrast to T. brucei PEX10 and PEX12, T. brucei PEX14 does not traffic to human peroxisomes, indicating that it is not recognized by the human PEX14 import mechanism.
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Affiliation(s)
- Tracy Saveria
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
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32
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Makiuchi T, Nara T, Annoura T, Hashimoto T, Aoki T. Occurrence of multiple, independent gene fusion events for the fifth and sixth enzymes of pyrimidine biosynthesis in different eukaryotic groups. Gene 2007; 394:78-86. [PMID: 17383832 DOI: 10.1016/j.gene.2007.02.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 02/13/2007] [Accepted: 02/13/2007] [Indexed: 02/06/2023]
Abstract
The genes encoding orotate phosphoribosyltransferase (OPRT) and orotidine-5'-monophosphate decarboxylase (OMPDC), the fifth and sixth enzymes in the de novo pyrimidine biosynthetic pathway, are fused as OPRT-OMPDC in most eukaryotic groups. On the other hand, the inversely linked OMPDC-OPRT fusion is present in trypanosomatids, belonging to kinetoplastids together with bodonids in a supergroup, Euglenozoa. Here, we show the presence of OMPDC-OPRT in the bodonid, Bodo caudatus, while OPRT-OMPDC in Euglena gracilis, another euglenozoan species belonging to euglenoids. These results suggest that the OMPDC-OPRT fusion event occurred in a common ancestor of kinetoplastids. Genome sequence database searches further revealed the presence of OMPDC-OPRT in stramenopiles and cyanobacteria. Phylogenetic reconstruction of OPRT and OMPDC rejected statistically the monophyly of the OPRT domains of stramenopile and kinetoplastid OMPDC-OPRT, demonstrating that these gene fusions do not share a common evolutionary origin, despite the identical gene order. Thus, the OMPDC-OPRT fusion is likely to have emerged independently in these eukaryotic groups. Phylogenetic analyses also suggested that cyanobacterial OMPDC-OPRT arose via lateral transfer. We conclude that gene fusion events occur more frequently than previously thought and that lateral gene transfer has made a marked contribution to establishment of the rearranged structure of OPRT and OMPDC genes in eukaryotes.
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Affiliation(s)
- Takashi Makiuchi
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan
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33
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Galland N, Demeure F, Hannaert V, Verplaetse E, Vertommen D, Van der Smissen P, Courtoy PJ, Michels PAM. Characterization of the role of the receptors PEX5 and PEX7 in the import of proteins into glycosomes of Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:521-35. [PMID: 17320990 DOI: 10.1016/j.bbamcr.2007.01.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 12/20/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
Peroxins 5 and 7 are receptors for protein import into the peroxisomal matrix. We studied the involvement of these peroxins in the biogenesis of glycosomes in the protozoan parasite Trypanosoma brucei. Glycosomes are peroxisome-like organelles in which a major part of the glycolytic pathway is sequestered. We here report the characterization of the T. brucei homologue of PEX7 and provide several data strongly suggesting that it can bind to PEX5. Depletion of PEX5 or PEX7 by RNA interference had a severe effect on the growth of both the bloodstream-form of the parasite, that relies entirely on glycolysis for its ATP supply, and the procyclic form representative of the parasite living in the tsetse-fly midgut and in which also other metabolic pathways play a prominent role. The role of the two receptors in import of glycosomal matrix proteins with different types of peroxisome/glycosome-targeting signals (PTS) was analyzed by immunofluorescence and subcellular fractionation studies. Knocking down the expression of either receptor gene resulted, in procyclic cells, in the mislocalization of proteins with both a type 1 or 2 targeting motif (PTS1, PTS2) located at the C- and N-termini, respectively, and proteins with a sequence-internal signal (I-PTS) to the cytosol. Electron microscopy confirmed the apparent integrity of glycosomes in these procyclic cells. In bloodstream-form trypanosomes, PEX7 depletion seemed to affect only the subcellular distribution of PTS2-proteins. Western blot analysis suggested that, in both life-cycle stages of the trypanosome, the levels of both receptors are controlled in a coordinated fashion, by a mechanism that remains to be determined. The observation that both PEX5 and PEX7 are essential for the viability of the parasite indicates that the respective branches of the glycosome-import pathway in which each receptor acts might be interesting drug targets.
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Affiliation(s)
- Nathalie Galland
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
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34
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Brocard C, Hartig A. Peroxisome targeting signal 1: is it really a simple tripeptide? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1565-73. [PMID: 17007944 DOI: 10.1016/j.bbamcr.2006.08.022] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 08/10/2006] [Accepted: 08/18/2006] [Indexed: 10/24/2022]
Abstract
Originally, the peroxisomal targeting signal 1 (PTS1) was defined as a tripeptide at the C-terminus of proteins prone to be imported into the peroxisomal matrix. The corresponding receptor PEX5 initiates the translocation of proteins by identifying potential substrates via their C-termini and trapping PTS1s through remodeling of its TPR domain. Thorough studies on the interaction between PEX5 and PTS1 as well as sequence-analytic tools revealed the influence of amino acid residues further upstream of the ultimate tripeptide. Altogether, PTS1s should be defined as dodecamer sequences at the C-terminal ends of proteins. These sequences accommodate physical contacts with both the surface and the binding cavity of PEX5 and ensure accessibility of the extreme C-terminus. Knowledge-based approaches in applied Bioinformatics provide reliable tools to accurately predict the peroxisomal location of proteins not yet determined experimentally.
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Affiliation(s)
- Cécile Brocard
- Max F Perutz Laboratories, University of Vienna, Department of Biochemistry, Dr. Bohrgasse 9, 1030 Vienna, Austria.
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35
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Branchini BR, Southworth TL, DeAngelis JP, Roda A, Michelini E. Luciferase from the Italian firefly Luciola italica: molecular cloning and expression. Comp Biochem Physiol B Biochem Mol Biol 2006; 145:159-67. [PMID: 16916615 DOI: 10.1016/j.cbpb.2006.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 06/04/2006] [Accepted: 06/05/2006] [Indexed: 10/24/2022]
Abstract
The cDNA encoding the luciferase from the Italian firefly Luciola italica was cloned using reverse transcriptase-PCR and a gene-specific primer set based on the DNA sequence of Luciola mingrelica. The cDNA sequence of L. italica luciferase was determined to be 1647 base pairs in length with an open reading frame of 548 amino acids. Phylogenetic analysis of the protein sequence demonstrated that this luciferase is closely related to that of other fireflies of the Lampyridae family, particularly within the Luciolinae subfamily, showing 96% homology to luciferases from the fireflies Hotaria unmunsana and Hotaria parvula. The specific activity of the L. italica luciferase was 78% of the North American enzyme, after correction for emission color differences. The bioluminescence emission of the Italian firefly is pH sensitive with maxima at 566 nm and 614 nm at pH 7.8 and 6.0, respectively. Interestingly, the total bioluminescence output was approximately 2-fold greater than that of P. pyralis luciferase due to differences in turnover characteristics evidenced by extended light emission decay kinetics. We expect that this newly discovered luciferase will be suitable for a wide range of bioluminescence applications including in vivo imaging and multiplex assays.
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Affiliation(s)
- Bruce R Branchini
- Department of Chemistry, Connecticut College, New London, Connecticut 06320, USA.
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36
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Rothberg KG, Burdette DL, Pfannstiel J, Jetton N, Singh R, Ruben L. The RACK1 homologue from Trypanosoma brucei is required for the onset and progression of cytokinesis. J Biol Chem 2006; 281:9781-90. [PMID: 16469736 PMCID: PMC1997280 DOI: 10.1074/jbc.m600133200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The receptor for activated C kinase 1 (RACK1) is a conserved scaffold protein that helps regulate a range of cell activities including cell growth, shape, and protein translation. We report that a homologue of RACK1 is required for cytokinesis in pathogenic Trypanosoma brucei. The protein, referred to as TRACK, is comprised of WD repeat elements and can complement cpc2 null mutants of Schizosaccharomyces pombe. TRACK is expressed throughout the trypanosome life cycle and is distributed predominantly in a perinuclear region and the cytoplasm but not along the endoplasmic reticulum, mitochondrion, or cleavage furrow of dividing cells. When tetracycline-inducible RNA interference (RNAi) is used to deplete the cellular content of TRACK, the cells remain metabolically active, but growth is inhibited. In bloodstream forms, growth arrest is due to a delay in the onset of cytokinesis. By contrast, procyclic forms are able to initiate cytokinesis in the absence of TRACK but arrest midway through cell cleavage. The RNAi cells undergo multiple rounds of partial cytokinesis and accumulate nuclei and cytoplasmic extensions with attached flagella. The TRACK RNAi construct is also inducible within infected mice. Under these conditions parasites are eliminated from peripheral blood within 3 days post-infection. Taken as a whole, these data indicate that trypanosomes utilize a RACK1 homologue to regulate the final stages of mitosis. Moreover, disrupting the interaction between TRACK and its partners might be targeted in the design of novel therapies.
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Affiliation(s)
- Karen G Rothberg
- Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275, USA
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37
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Dufernez F, Yernaux C, Gerbod D, Noël C, Chauvenet M, Wintjens R, Edgcomb VP, Capron M, Opperdoes FR, Viscogliosi E. The presence of four iron-containing superoxide dismutase isozymes in trypanosomatidae: characterization, subcellular localization, and phylogenetic origin in Trypanosoma brucei. Free Radic Biol Med 2006; 40:210-25. [PMID: 16413404 DOI: 10.1016/j.freeradbiomed.2005.06.021] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 06/27/2005] [Accepted: 06/27/2005] [Indexed: 10/25/2022]
Abstract
Metalloenzymes such as the superoxide dismutases (SODs) form part of a defense mechanism that helps protect obligate and facultative aerobic organisms from oxygen toxicity and damage. Here, we report the presence in the trypanosomatid genomes of four SOD genes: soda, sodb1, sodb2, and a newly identified sodc. All four genes of Trypanosoma brucei have been cloned (Tbsods), sequenced, and overexpressed in Escherichia coli and shown to encode active dimeric FeSOD isozymes. Homology modeling of the structures of all four enzymes using available X-ray crystal structures of homologs showed that the four TbSOD structures were nearly identical. Subcellular localization using GFP-fusion proteins in procyclic insect trypomastigotes shows that TbSODB1 is mainly cytosolic, with a minor glycosomal component, TbSODB2 is mainly glycosomal with some activity in the cytosol, and TbSODA and TbSODC are both mitochondrial isozymes. Phylogenetic studies of all available trypanosomatid SODs and 106 dimeric FeSODs and closely related cambialistic dimeric SOD sequences suggest that the trypanosomatid SODs have all been acquired by more than one event of horizontal gene transfer, followed by events of gene duplication.
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Affiliation(s)
- Fabienne Dufernez
- Institut Pasteur, Inserm U547, 1 Rue du Professeur Calmette, B. P. 245, F-59019 Lille cedex, France
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38
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Banerjee SK, Kessler PS, Saveria T, Parsons M. Identification of trypanosomatid PEX19: functional characterization reveals impact on cell growth and glycosome size and number. Mol Biochem Parasitol 2005; 142:47-55. [PMID: 15907560 DOI: 10.1016/j.molbiopara.2005.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 03/21/2005] [Accepted: 03/21/2005] [Indexed: 10/25/2022]
Abstract
Glycosomes are peroxisome-like organelles present in trypanosomatid pathogens. These organelles compartmentalize glycolysis, among other reactions, and are essential in both bloodstream and procyclic form Trypanosoma brucei. Peroxins (PEXs) are proteins necessary for biogenesis of peroxisomes and glycosomes. In each assembled trypanosomatid genome, we identified a predicted protein with approximately 20% sequence identity to human PEX19, a protein required for insertion of peroxisomal membrane proteins (PMPs) into the membrane. Functional analysis demonstrated that these proteins are indeed PEX19 orthologues. Like other PEX19s, T. brucei and Leishmania major PEX19 GFP fusion proteins are predominantly cytosolic. We further showed that LmPEX19 interacts with the glycosomal membrane protein PEX2 in the yeast two-hybrid system. Partial knockdown of TbPEX19 slowed parasite growth, particularly when glucose was present. Immunofluorescence and electron microscopic studies revealed biogenesis defect as evidenced by a sharp reduction in the number of glycosomes. Surprisingly, a four-fold increase in the size of the remaining glycosomes was observed. We propose that this phenotype of fewer but larger glycosomes results from the reduction in import of glycosomal membrane proteins.
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Affiliation(s)
- Sanjiban K Banerjee
- Seattle Biomedical Research Institute, 307 Westlake Avenue N., Seattle, WA 98109, USA
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Veitch N, Maugeri D, Cazzulo J, Lindqvist Y, Barrett M. Transketolase from Leishmania mexicana has a dual subcellular localization. Biochem J 2005; 382:759-67. [PMID: 15149284 PMCID: PMC1133835 DOI: 10.1042/bj20040459] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Revised: 04/29/2004] [Accepted: 05/19/2004] [Indexed: 11/17/2022]
Abstract
Transketolase has been characterized in Leishmania mexicana. A gene encoding this enzyme was identified and cloned. The gene was expressed in Escherichia coli and the protein was purified and characterized. An apparent K(m) of 2.75 mM for ribose 5-phosphate was determined. X-ray crystallography was used to determine the three-dimensional structure of the enzyme to a resolution of 2.2 A (1 A identical with 0.1 nm). The C-terminus of the protein contains a type-1 peroxisome-targeting signal, suggestive of a possible glycosomal subcellular localization. Subcellular localization experiments performed with promastigote forms of the parasite revealed that the protein was predominantly cytosolic, although a significant component of the total activity was associated with the glycosomes. Transketolase is thus the first enzyme of the nonoxidative branch of the pentose phosphate pathway whose presence has been demonstrated in a peroxisome-like organelle.
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Affiliation(s)
- Nicola J. Veitch
- *Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - Dante A. Maugeri
- †Instituto de Investigaciones Biotecnologicas (IIB-INTECH), Universidad Nacional de General San Martin – CONICET, 1650 San Martin, Buenos Aires, Argentina
| | - Juan Jose Cazzulo
- †Instituto de Investigaciones Biotecnologicas (IIB-INTECH), Universidad Nacional de General San Martin – CONICET, 1650 San Martin, Buenos Aires, Argentina
| | - Ylva Lindqvist
- ‡Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- To whom correspondence should be addressed (email either or )
| | - Michael P. Barrett
- *Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
- To whom correspondence should be addressed (email either or )
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Moyersoen J, Choe J, Fan E, Hol WGJ, Michels PAM. Biogenesis of peroxisomes and glycosomes: trypanosomatid glycosome assembly is a promising new drug target. FEMS Microbiol Rev 2005; 28:603-43. [PMID: 15539076 DOI: 10.1016/j.femsre.2004.06.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/14/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022] Open
Abstract
In trypanosomatids (Trypanosoma and Leishmania), protozoa responsible for serious diseases of mankind in tropical and subtropical countries, core carbohydrate metabolism including glycolysis is compartmentalized in peculiar peroxisomes called glycosomes. Proper biogenesis of these organelles and the correct sequestering of glycolytic enzymes are essential to these parasites. Biogenesis of glycosomes in trypanosomatids and that of peroxisomes in other eukaryotes, including the human host, occur via homologous processes involving proteins called peroxins, which exert their function through multiple, transient interactions with each other. Decreased expression of peroxins leads to death of trypanosomes. Peroxins show only a low level of sequence conservation. Therefore, it seems feasible to design compounds that will prevent interactions of proteins involved in biogenesis of trypanosomatid glycosomes without interfering with peroxisome formation in the human host cells. Such compounds would be suitable as lead drugs against trypanosomatid-borne diseases.
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Affiliation(s)
- Juliette Moyersoen
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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41
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Kessler PS, Parsons M. Probing the role of compartmentation of glycolysis in procyclic form Trypanosoma brucei: RNA interference studies of PEX14, hexokinase, and phosphofructokinase. J Biol Chem 2005; 280:9030-6. [PMID: 15637070 DOI: 10.1074/jbc.m412033200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosoma brucei and related organisms contain an organelle evolutionarily related to peroxisomes that sequesters glycolysis, among other pathways. We have shown previously that disruption of protein import into this organelle, the glycosome, can be accomplished through RNA interference (RNAi)-mediated knockdown of the peroxin PEX14. Decreased PEX14 in turn leads to cell death, which, at least in the procyclic stage, can be triggered by the presence of glucose. Here we show that fructose, which is taken up and metabolized by procyclic form T. brucei, and glycerol, which interfaces with the glycosomal glycolytic pathway, are also toxic during PEX14 RNAi. Earlier computer modeling studies predicted that glycolysis would be toxic to T. brucei in the absence of glycosomal compartmentation because of the intrinsic lack of feedback regulation of the parasite hexokinase and phosphofructokinase. To further test this hypothesis, we performed double RNAi, targeting hexokinase and PEX14. Knockdown of hexokinase rescued PEX14 knockdown cells from glucose toxicity, even though glycosomal proteins continue to be mislocalized to the cytosol. Knockdown of phosphofructokinase was benign in the absence of glucose but toxic in the presence of glucose. When PEX14 and phosphofructokinase mRNAs were jointly targeted for RNAi, glycerol remained toxic to the parasites. Taken together, these data indicate that the glycosome provides significant, but not complete, protection of trypanosomes from the dangerous design of glycolysis.
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Affiliation(s)
- Peter S Kessler
- Seattle Biomedical Research Institute, Seattle, Washington 98109, USA
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42
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Reumann S. Specification of the peroxisome targeting signals type 1 and type 2 of plant peroxisomes by bioinformatics analyses. PLANT PHYSIOLOGY 2004; 135:783-800. [PMID: 15208424 PMCID: PMC514115 DOI: 10.1104/pp.103.035584] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2003] [Revised: 01/22/2004] [Accepted: 01/22/2004] [Indexed: 05/18/2023]
Abstract
To specify the C-terminal peroxisome targeting signal type 1 (PTS1) and the N-terminal PTS2 for higher plants, a maximum number of plant cDNAs and expressed sequence tags that are homologous to PTS1- and PTS2-targeted plant proteins was retrieved from the public databases and the primary structure of their targeting domains was analyzed for conserved properties. According to their high overall frequency in the homologs and their widespread occurence in different orthologous groups, nine major PTS1 tripeptides ([SA][RK][LM]> without AKM> plus SRI> and PRL>) and two major PTS2 nonapeptides (R[LI]x5HL) were defined that are considered good indicators for peroxisomal localization if present in unknown proteins. A lower but significant number of homologs contained 1 of 11 minor PTS1 tripeptides or of 9 minor PTS2 nonapeptides, many of which have not been identified before in plant peroxisomal proteins. The region adjacent to the PTS peptides was characterized by specific conserved properties as well, such as a pronounced incidence of basic and Pro residues and a high positive net charge, which probably play an auxiliary role in peroxisomal targeting. By contrast, several peptides with assumed peroxisomal targeting properties were not found in any of the 550 homologs and hence play--if at all--only a minor role in peroxisomal targeting. Based on the definition of these major and minor PTS and on the recognition of additional conserved properties, the accuracy of predicting peroxisomal proteins can be raised and plant genomes can be screened for novel proteins of peroxisomes more successfully.
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Affiliation(s)
- Sigrun Reumann
- Albrecht-von-Haller-Institute for Plant Sciences, Department for Plant Biochemistry, D-37077 Goettingen, Germany
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43
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Zarella-Boitz JM, Rager N, Jardim A, Ullman B. Subcellular localization of adenine and xanthine phosphoribosyltransferases in Leishmania donovani. Mol Biochem Parasitol 2004; 134:43-51. [PMID: 14747142 DOI: 10.1016/j.molbiopara.2003.08.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The subcellular location of a protein is a critical factor in its physiological function and an important consideration in therapeutic paradigms that target the protein. Because Leishmania donovani cannot synthesize purine nucleotides de novo, they rely predominantly upon therapeutically germane phosphoribosyltransferase (PRT) enzymes, hypoxanthine-guanine PRT (HGPRT), adenine PRT (APRT), and xanthine PRT (XPRT), for purine acquisition from the host. Previous studies have shown that the L. donovani HGPRT is localized to the glycosome, a fuel-metabolizing microbody that is unique to kinetoplastid parasites [J. Biol. Chem. 273 (1998) 1534]. The sequences of the other two PRTs indicate that XPRT, but not APRT, possesses a COOH-terminal tripeptide that mediates protein targeting to the glycosome. To determine definitively the intracellular milieu of APRT and XPRT, polyclonal antibodies were raised to each recombinant protein. APRT and XPRT were then shown by immunofluorescence to be localized to the cytosol and glycosome, respectively. The glycosomal milieu for XPRT was also verified by immunoelectron microscopy. Amputation of the glycosomal targeting signal from XPRT resulted in protein mislocalization to the cytosol, but the cytosolic xprt was still functional with respect to purine salvage. These studies establish that APRT is cytosolic and XPRT, like the homologous HGPRT, is glycosomal and demonstrate that a mutant xprt protein that mislocalizes to the cytosol is still functional and supports parasite viability.
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Affiliation(s)
- Jan M Zarella-Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
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García-Salcedo JA, Gijón P, Nolan DP, Tebabi P, Pays E. A chromosomal SIR2 homologue with both histone NAD-dependent ADP-ribosyltransferase and deacetylase activities is involved in DNA repair in Trypanosoma brucei. EMBO J 2003; 22:5851-62. [PMID: 14592982 PMCID: PMC275410 DOI: 10.1093/emboj/cdg553] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
SIR2-like proteins have been implicated in a wide range of cellular events including chromosome silencing, chromosome segregation, DNA recombination and the determination of life span. We report here the molecular and functional characterization of a SIR2-related protein from the protozoan parasite Trypanosoma brucei, which we termed TbSIR2RP1. This protein is a chromosome-associated NAD-dependent enzyme which, in contrast to other known proteins of this family, catalyses both ADP-ribosylation and deacetylation of histones, particulary H2A and H2B. Under- or overexpression of TbSIR2RP1 decreased or increased, respectively, cellular resistance to DNA damage. Treatment of trypanosomal nuclei with a DNA alkylating agent resulted in a significant increase in the level of histone ADP-ribosylation and a concomitant increase in chromatin sensitivity to micrococcal nuclease. Both of these responses correlated with the level of TbSIR2RP1 expression. We propose that histone modification by TbSIR2RP1 is involved in DNA repair.
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Affiliation(s)
- José A García-Salcedo
- Institute of Molecular Biology and Medicine, Free University of Brussels, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium.
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Plewes KA, Barr SD, Gedamu L. Iron superoxide dismutases targeted to the glycosomes of Leishmania chagasi are important for survival. Infect Immun 2003; 71:5910-20. [PMID: 14500512 PMCID: PMC201062 DOI: 10.1128/iai.71.10.5910-5920.2003] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kinetoplastid glycosomes contain a variety of metabolic activities, such as glycolysis, beta-oxidation of fatty acids, lipid biosynthesis, and purine salvage. One advantage of sequestering metabolic activities is the avoidance of cellular oxidative damage by reactive oxygen species produced as a by-product of metabolism. Little is known about how glycosomes themselves withstand these toxic metabolites. We previously isolated an iron superoxide dismutase from Leishmania chagasi that is expressed at low levels in the early logarithmic promastigote stage and increases toward the stationary promastigote and amastigote stages. We have since identified a second highly homologous Lcfesodb gene that is expressed at high levels in the early logarithmic promastigote stage and decreases toward the stationary promastigote and amastigote stages. Localization studies using green fluorescent protein fusions have revealed that LcFeSODB1 and LcFeSODB2 are localized within the glycosomes by the last three amino acids of their carboxyl termini. To better understand the specific role that FeSODB plays in parasite growth and survival, a single-allele knockout of the Lcfesodb1 gene was generated. The parasites with these genes exhibited a significant reduction in growth when endogenous superoxide levels were increased with paraquat in culture. Furthermore, the FeSODB1-deficient parasites exhibited a significant reduction in survival within human macrophages. Our results suggest that LcFeSODB plays an important role in parasite growth and survival by protecting glycosomes from superoxide toxicity.
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Affiliation(s)
- Katherine A Plewes
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
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Luque-Ortega JR, Saugar JM, Chiva C, Andreu D, Rivas L. Identification of new leishmanicidal peptide lead structures by automated real-time monitoring of changes in intracellular ATP. Biochem J 2003; 375:221-30. [PMID: 12864731 PMCID: PMC1223672 DOI: 10.1042/bj20030544] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2003] [Revised: 07/11/2003] [Accepted: 07/15/2003] [Indexed: 11/17/2022]
Abstract
Leishmanicidal drugs interacting stoichiometrically with parasite plasma membrane lipids, thus promoting permeability, have raised significant expectations for Leishmania chemotherapy due to their nil or very low induction of resistance. Inherent in this process is a decrease in intracellular ATP, either wasted by ionic pumps to restore membrane potential or directly leaked through larger membrane lesions caused by the drug. We have adapted a luminescence method for fast automated real-time monitoring of this process, using Leishmania donovani promastigotes transfected with a cytoplasmic luciferase form, previously tested for anti-mitochondrial drugs. The system was first assayed against a set of well-known membrane-active drugs [amphotericin B, nystatin, cecropin A-melittin peptide CA(1-8)M(1-18)], plus two ionophoric polyethers (narasin and salinomycin) not previously tested on Leishmania, then used to screen seven new cecropin A-melittin hybrid peptides. All membrane-active compounds showed a good correlation between inhibition of luminescence and leishmanicidal activity. Induction of membrane permeability was demonstrated by dissipation of membrane potential, SYTOX trade mark Green influx and membrane damage assessed by electron microscopy, except for the polyethers, where ATP decrease was due to inhibition of its mitochondrial synthesis. Five of the test peptides showed an ED50 around 1 microM on promastigotes. These peptides, with equal or better activity than 26-residue-long CA(1-8)M(1-18), are the shortest leishmanicidal peptides described so far, and validate our luminescence assay as a fast and cheap screening tool for membrane-active compounds.
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47
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Barr SD, Gedamu L. Role of peroxidoxins in Leishmania chagasi survival. Evidence of an enzymatic defense against nitrosative stress. J Biol Chem 2003; 278:10816-23. [PMID: 12529367 DOI: 10.1074/jbc.m212990200] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The mechanisms by which Leishmania parasites survive exposure to highly reactive oxygen (ROS) and nitrogen (RNS) species within phagosomes of macrophages are not well known. Recently it has been shown that RNS alone is sufficient and necessary to control Leishmania donovani infection in mice (Murray, H. W., and Nathan, C. F. (1999) J. Exp. Med. 189, 741-746). No enzymatic defense against RNS has been discovered in Leishmania to date. We have previously isolated two peroxidoxins (LcPxn1 and LcPxn2) from Leishmania chagasi and showed that recombinant LcPxn1 protein was capable of detoxifying hydrogen peroxide, hydroperoxide, and hydroxyl radicals (Barr, S. D., and Gedamu, L. (2001) J. Biol. Chem. 276, 34279-34287). In further characterizing the physiological role of peroxidoxins in Leishmania survival, we show here that recombinant LcPxn1 protein can detoxify RNS in addition to ROS, whereas recombinant LcPxn2 protein can only detoxify hydrogen peroxide. LcPxn1 and LcPxn2 are localized to the cytoplasm, and overexpression of LcPxn1 in L. chagasi parasites enhanced survival when exposed to exogenous ROS and RNS and enhanced survival within U937 macrophage cells. Site-directed mutagenesis studies revealed that the conserved Cys-52 residue is essential for detoxifying hydrogen peroxide, t-butyl hydroperoxide, and hydroxyl radicals, whereas the conserved Cys-173 residue is essential for detoxifying t-butyl hydroperoxide and peroxynitrite. This is the first report of an enzymatic defense against RNS in Leishmania.
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Affiliation(s)
- Stephen D Barr
- Department of Biological Sciences, University of Calgary, Alberta T2N 1N4, Canada
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Hillebrand H, Schmidt A, Krauth-Siegel RL. A second class of peroxidases linked to the trypanothione metabolism. J Biol Chem 2003; 278:6809-15. [PMID: 12466271 DOI: 10.1074/jbc.m210392200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosoma brucei, the causative agent of African sleeping sickness, has three nearly identical genes encoding cysteine homologues of classical selenocysteine-containing glutathione peroxidases. The proteins are expressed in the mammalian and insect stages of the parasite. One of the genes, which contains a mitochondrial as well as a glycosomal targeting signal has been overexpressed. The recombinant T. brucei peroxidase has a high preference for the trypanothione/tryparedoxin couple as electron donor for the reduction of different hydroperoxides but accepts also T. brucei thioredoxin. The apparent rate constants k(2)' for the regeneration of the reduced enzyme are 2 x 10(5) m(-1) s(-1) with tryparedoxin and 5 x 10(3) m(-1) s(-1) with thioredoxin. No saturation kinetics was observed and the rate-limiting step of the overall reaction is reduction of the hydroperoxide. With glutathione, the peroxidase has marginal activity and reduction of the enzymes becomes limiting with a k(2)' value of 3 m (-1) s(-1). The T. brucei peroxidase, in contrast to the related Trypanosoma cruzi enzyme, also accepts hydrogen peroxide as substrate. The catalytic efficiency of the peroxidase studied here is comparable with that of the peroxiredoxin-like tryparedoxin peroxidases, which shows that trypanosomes possess two distinct peroxidase systems both dependent on the unique dithiol trypanothione.
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Affiliation(s)
- Henning Hillebrand
- Biochemie-Zentrum Heidelberg, Universität Heidelberg, 69120 Heidelberg, Germany
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Furuya T, Kessler P, Jardim A, Schnaufer A, Crudder C, Parsons M. Glucose is toxic to glycosome-deficient trypanosomes. Proc Natl Acad Sci U S A 2002; 99:14177-82. [PMID: 12386344 PMCID: PMC137857 DOI: 10.1073/pnas.222454899] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2002] [Indexed: 11/18/2022] Open
Abstract
Trypanosomatids, the etiologic agents of sleeping sickness, leishmaniasis, and Chagas' disease, compartmentalize glycolysis within glycosomes, metabolic organelles related to peroxisomes. Here, we identify a trypanosome homologue of PEX14, one of the components of the peroxisomal protein import docking complex. We have used double-stranded RNA interference to target the PEX14 transcript for degradation. Glycosomal matrix protein import was compromised, and both glycolytic bloodstream stage parasites and mitochondrially respiring procyclic stage parasites were killed. Thus, unlike peroxisomes, glycosomes are essential organelles. Surprisingly, procyclic forms, which can grow in the absence of glucose, were killed by PEX14 RNA interference only when simple sugars were present. Thus, interference with glycosome protein import makes glucose toxic to trypanosomes.
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Affiliation(s)
- Tetsuya Furuya
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
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50
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López C, Chevalier N, Hannaert V, Rigden DJ, Michels PAM, Ramirez JL. Leishmania donovani phosphofructokinase. Gene characterization, biochemical properties and structure-modeling studies. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3978-89. [PMID: 12180974 DOI: 10.1046/j.1432-1033.2002.03086.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The characterization of the gene encoding Leishmania donovani phosphofructokinase (PFK) and the biochemical properties of the expressed enzyme are reported. L. donovani has a single PFK gene copy per haploid genome that encodes a polypeptide with a deduced molecular mass of 53 988 and a pI of 9.26. The predicted amino acid sequence contains a C-terminal tripeptide that conforms to an established signal for glycosome targeting. L. donovani PFK showed most sequence similarity to inorganic pyrophosphate (PPi)-dependent PFKs, despite being ATP-dependent. It thereby resembles PFKs from other Kinetoplastida such as Trypanosoma brucei, Trypanoplasma borreli (characterized in this study), and a PFK found in Entamoeba histolytica. It exhibited hyperbolic kinetics with respect to ATP whereas the binding of the other substrate, fructose 6-phosphate, showed slight positive cooperativity. PPi, even at high concentrations, did not have any effect. AMP acted as an activator of PFK, shifting its kinetics for fructose 6-phosphate from slightly sigmoid to hyperbolic, and increasing considerably the affinity for this substrate, whereas GDP did not have any effect. Modelling studies and site-directed mutagenesis were employed to shed light on the structural basis for the AMP effector specificity and on ATP/PPi specificity among PFKs.
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Affiliation(s)
- Claudia López
- Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, Venezuela
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