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Yadav S, Anand A, Ramalingam K, Balodi DC, Maras JS, Goyal N. Unraveling of interacting protein network of chaperonin TCP1 gamma subunit of Leishmania donovani. Cell Stress Chaperones 2022; 27:205-222. [PMID: 35199315 PMCID: PMC9106790 DOI: 10.1007/s12192-022-01262-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 11/03/2022] Open
Abstract
T-complex polypeptide-1 (TCP1) is a group II chaperonin that folds various cellular proteins. About 10% of cytosolic proteins in yeast have been shown to flux through the TCP1 protein complex indicating that it interacts and folds a plethora of substrate proteins that perform essential functions. In Leishmania donovani, the gamma subunit of TCP1 (LdTCP1γ) has been shown to form a homo-oligomeric complex and exhibited ATP-dependent protein folding activity. LdTCP1γ is essential for the growth and infectivity of the parasite. The interacting partners of L. donovani TCP1γ, involved in many cellular processes, are far from being understood. In this study, we utilized co-immunoprecipitation assay coupled with liquid chromatography-mass spectrometry (LC-MS) to unravel protein-protein interaction (PPI) networks of LdTCP1γ in the L. donovani parasite. Label-free quantification (LFQ) proteomic analysis revealed 719 interacting partners of LdTCP1γ. String analysis showed that LdTCP1γ interacts with all subunits of TCP1 complex as well as other proteins belonging to pathways like metabolic process, ribosome, protein folding, sorting, and degradation. Trypanothione reductase, identified as one of the interacting partners, is refolded by LdTCP1γ. In addition, the differential expression of LdTCP1γ modulates the trypanothione reductase activity in L. donovani parasite. The study provides novel insight into the role of LdTCP1γ that will pave the way to better understand parasite biology by identifying the interacting partners of this chaperonin.
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Affiliation(s)
- Shailendra Yadav
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Gaziabaad, 201002, India
| | - Apeksha Anand
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Gaziabaad, 201002, India
| | - Karthik Ramalingam
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Deep Chandra Balodi
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Gaziabaad, 201002, India
| | - Jaswinder Singh Maras
- Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, New Delhi, 110070, India
| | - Neena Goyal
- Division of Biochemistry and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- Academy of Scientific and Innovative Research (AcSIR), Gaziabaad, 201002, India.
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Parreira de Aquino G, Mendes Gomes MA, Köpke Salinas R, Laranjeira-Silva MF. Lipid and fatty acid metabolism in trypanosomatids. MICROBIAL CELL 2021; 8:262-275. [PMID: 34782859 PMCID: PMC8561143 DOI: 10.15698/mic2021.11.764] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022]
Abstract
Trypanosomiases and leishmaniases are neglected tropical diseases that have been spreading to previously non-affected areas in recent years. Identification of new chemotherapeutics is needed as there are no vaccines and the currently available treatment options are highly toxic and often ineffective. The causative agents for these diseases are the protozoan parasites of the Trypanosomatidae family, and they alternate between invertebrate and vertebrate hosts during their life cycles. Hence, these parasites must be able to adapt to different environments and compete with their hosts for several essential compounds, such as amino acids, vitamins, ions, carbohydrates, and lipids. Among these nutrients, lipids and fatty acids (FAs) are essential for parasite survival. Trypanosomatids require massive amounts of FAs, and they can either synthesize FAs de novo or scavenge them from the host. Moreover, FAs are the major energy source during specific life cycle stages of T. brucei, T. cruzi, and Leishmania. Therefore, considering the distinctive features of FAs metabolism in trypanosomatids, these pathways could be exploited for the development of novel antiparasitic drugs. In this review, we highlight specific aspects of lipid and FA metabolism in the protozoan parasites T. brucei, T. cruzi, and Leishmania spp., as well as the pathways that have been explored for the development of new chemotherapies.
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Affiliation(s)
| | | | - Roberto Köpke Salinas
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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Mabille D, Cardoso Santos C, Hendrickx R, Claes M, Takac P, Clayton C, Hendrickx S, Hulpia F, Maes L, Van Calenbergh S, Caljon G. 4E Interacting Protein as a Potential Novel Drug Target for Nucleoside Analogues in Trypanosoma brucei. Microorganisms 2021; 9:microorganisms9040826. [PMID: 33924674 PMCID: PMC8069773 DOI: 10.3390/microorganisms9040826] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 12/22/2022] Open
Abstract
Human African trypanosomiasis is a neglected parasitic disease for which the current treatment options are quite limited. Trypanosomes are not able to synthesize purines de novo and thus solely depend on purine salvage from the host environment. This characteristic makes players of the purine salvage pathway putative drug targets. The activity of known nucleoside analogues such as tubercidin and cordycepin led to the development of a series of C7-substituted nucleoside analogues. Here, we use RNA interference (RNAi) libraries to gain insight into the mode-of-action of these novel nucleoside analogues. Whole-genome RNAi screening revealed the involvement of adenosine kinase and 4E interacting protein into the mode-of-action of certain antitrypanosomal nucleoside analogues. Using RNAi lines and gene-deficient parasites, 4E interacting protein was found to be essential for parasite growth and infectivity in the vertebrate host. The essential nature of this gene product and involvement in the activity of certain nucleoside analogues indicates that it represents a potential novel drug target.
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Affiliation(s)
- Dorien Mabille
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
| | - Camila Cardoso Santos
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
- Laboratório de Biologia Celular (LBC), Instituto Oswaldo Cruz (IOC/Fiocruz), Rio de Janeiro 21040-900, Brazil
| | - Rik Hendrickx
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
| | - Mathieu Claes
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
| | - Peter Takac
- Institute of Zoology, Slovak Academy of Sciences, 84506 Bratislava, Slovakia;
- Scientica, Ltd., 83106 Bratislava, Slovakia
| | - Christine Clayton
- DKFZ-ZMBH Alliance, Zentrum für Molekulare Biologie der Universität Heidelberg, 69120 Heidelberg, Germany;
| | - Sarah Hendrickx
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, 9000 Gent, Belgium; (F.H.); (S.V.C.)
| | - Louis Maes
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
| | - Serge Van Calenbergh
- Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, 9000 Gent, Belgium; (F.H.); (S.V.C.)
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, 2610 Wilrijk, Belgium; (D.M.); (C.C.S.); (R.H.); (M.C.); (S.H.); (L.M.)
- Correspondence:
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Lucena ACR, Amorim JC, de Paula Lima CV, Batista M, Krieger MA, de Godoy LMF, Marchini FK. Quantitative phosphoproteome and proteome analyses emphasize the influence of phosphorylation events during the nutritional stress of Trypanosoma cruzi: the initial moments of in vitro metacyclogenesis. Cell Stress Chaperones 2019; 24:927-936. [PMID: 31368045 PMCID: PMC6717228 DOI: 10.1007/s12192-019-01018-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/15/2019] [Accepted: 06/14/2019] [Indexed: 12/16/2022] Open
Abstract
Phosphorylation is an important event in cell signaling that is modulated by kinases and phosphatases. In Trypanosoma cruzi, the etiological agent of Chagas disease, approximately 2% of the protein-coding genes encode for protein kinases. This parasite has a heteroxenic life cycle with four different development stages. In the midgut of invertebrate vector, epimastigotes differentiate into metacyclic trypomastigotes in a process known as metacyclogenesis. This process can be reproduced in vitro by submitting parasites to nutritional stress (NS). Aiming to contribute to the elucidation of mechanisms that trigger metacyclogenesis, we applied super-SILAC (super-stable isotope labeling by amino acids in cell culture) and LC-MS/MS to analyze different points during NS. This analysis resulted in the identification of 4205 protein groups and 3643 phosphopeptides with the location of 4846 phosphorylation sites. Several phosphosites were considered modulated along NS and are present in proteins associated with various functions, such as fatty acid synthesis and the regulation of protein expression, reinforcing the importance of phosphorylation and signaling events to the parasite. These modulated sites may be triggers of metacyclogenesis.
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Affiliation(s)
- Aline Castro Rodrigues Lucena
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Juliana Carolina Amorim
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Carla Vanessa de Paula Lima
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Michel Batista
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
- Mass Spectrometry Facility RPT02H, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Marco Aurelio Krieger
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Lyris Martins Franco de Godoy
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil
| | - Fabricio Klerynton Marchini
- Laboratory of Applied Science and Technologies in Health, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil.
- Mass Spectrometry Facility RPT02H, Carlos Chagas Institute, Fiocruz, Curitiba, Parana, Brazil.
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Abstract
To satisfy its fatty acid needs, the extracellular eukaryotic parasite Trypanosoma brucei relies on two mechanisms: uptake of fatty acids from the host and de novo synthesis. We hypothesized that T. brucei modulates fatty acid synthesis in response to environmental lipid availability. The first committed step in fatty acid synthesis is catalyzed by acetyl coenzyme A (acetyl-CoA) carboxylase (ACC) and serves as a key regulatory point in other organisms. To test our hypothesis, T. brucei mammalian bloodstream and insect procyclic forms were grown in low-, normal-, or high-lipid media and the effect on T. brucei ACC (TbACC) mRNA, protein, and enzymatic activity was examined. In bloodstream form T. brucei, media lipids had no effect on TbACC expression or activity. In procyclic form T. brucei, we detected no change in TbACC mRNA levels but observed 2.7-fold-lower TbACC protein levels and 37% lower TbACC activity in high-lipid media than in low-lipid media. Supplementation of low-lipid media with the fatty acid stearate mimicked the effect of high lipid levels on TbACC activity. In procyclic forms, TbACC phosphorylation also increased 3.9-fold in high-lipid media compared to low-lipid media. Phosphatase treatment of TbACC increased activity, confirming that phosphorylation represented an inhibitory modification. Together, these results demonstrate a procyclic-form-specific environmental lipid response pathway that regulates TbACC posttranscriptionally, through changes in protein expression and phosphorylation. We propose that this environmental response pathway enables procyclic-form T. brucei to monitor the host lipid supply and downregulate fatty acid synthesis when host lipids are abundant and upregulate fatty acid synthesis when host lipids become scarce.IMPORTANCETrypanosoma brucei is a eukaryotic parasite that causes African sleeping sickness. T. brucei is transmitted by the blood-sucking tsetse fly. In order to adapt to its two very different hosts, T. brucei must sense the host environment and alter its metabolism to maximize utilization of host resources and minimize expenditure of its own resources. One key nutrient class is represented by fatty acids, which the parasite can either take from the host or make themselves. Our work describes a novel environmental regulatory pathway for fatty acid synthesis where the parasite turns off fatty acid synthesis when environmental lipids are abundant and turns on synthesis when the lipid supply is scarce. This pathway was observed in the tsetse midgut form but not the mammalian bloodstream form. However, pharmacological activation of this pathway in the bloodstream form to turn fatty acid synthesis off may be a promising new avenue for sleeping sickness drug discovery.
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Millerioux Y, Mazet M, Bouyssou G, Allmann S, Kiema TR, Bertiaux E, Fouillen L, Thapa C, Biran M, Plazolles N, Dittrich-Domergue F, Crouzols A, Wierenga RK, Rotureau B, Moreau P, Bringaud F. De novo biosynthesis of sterols and fatty acids in the Trypanosoma brucei procyclic form: Carbon source preferences and metabolic flux redistributions. PLoS Pathog 2018; 14:e1007116. [PMID: 29813135 PMCID: PMC5993337 DOI: 10.1371/journal.ppat.1007116] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/08/2018] [Accepted: 05/22/2018] [Indexed: 12/27/2022] Open
Abstract
De novo biosynthesis of lipids is essential for Trypanosoma brucei, a protist responsible for the sleeping sickness. Here, we demonstrate that the ketogenic carbon sources, threonine, acetate and glucose, are precursors for both fatty acid and sterol synthesis, while leucine only contributes to sterol production in the tsetse fly midgut stage of the parasite. Degradation of these carbon sources into lipids was investigated using a combination of reverse genetics and analysis of radio-labelled precursors incorporation into lipids. For instance, (i) deletion of the gene encoding isovaleryl-CoA dehydrogenase, involved in the leucine degradation pathway, abolished leucine incorporation into sterols, and (ii) RNAi-mediated down-regulation of the SCP2-thiolase gene expression abolished incorporation of the three ketogenic carbon sources into sterols. The SCP2-thiolase is part of a unidirectional two-step bridge between the fatty acid precursor, acetyl-CoA, and the precursor of the mevalonate pathway leading to sterol biosynthesis, 3-hydroxy-3-methylglutaryl-CoA. Metabolic flux through this bridge is increased either in the isovaleryl-CoA dehydrogenase null mutant or when the degradation of the ketogenic carbon sources is affected. We also observed a preference for fatty acids synthesis from ketogenic carbon sources, since blocking acetyl-CoA production from both glucose and threonine abolished acetate incorporation into sterols, while incorporation of acetate into fatty acids was increased. Interestingly, the growth of the isovaleryl-CoA dehydrogenase null mutant, but not that of the parental cells, is interrupted in the absence of ketogenic carbon sources, including lipids, which demonstrates the essential role of the mevalonate pathway. We concluded that procyclic trypanosomes have a strong preference for fatty acid versus sterol biosynthesis from ketogenic carbon sources, and as a consequence, that leucine is likely to be the main source, if not the only one, used by trypanosomes in the infected insect vector digestive tract to feed the mevalonate pathway.
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Affiliation(s)
- Yoann Millerioux
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Muriel Mazet
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Guillaume Bouyssou
- Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, UMR-5200, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Stefan Allmann
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Tiila-Riikka Kiema
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Eloïse Bertiaux
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, INSERM U1201, Institut Pasteur, Paris, France
| | - Laetitia Fouillen
- Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, UMR-5200, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
- Metabolome Facility of Bordeaux, Functional Genomics Center, Villenave d'Ornon
| | - Chandan Thapa
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Marc Biran
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Nicolas Plazolles
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, Bordeaux, France
| | - Franziska Dittrich-Domergue
- Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, UMR-5200, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Aline Crouzols
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, INSERM U1201, Institut Pasteur, Paris, France
| | - Rik K. Wierenga
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, INSERM U1201, Institut Pasteur, Paris, France
| | - Patrick Moreau
- Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, UMR-5200, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, CNRS UMR-5234, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
- * E-mail:
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Herrera LJ, Brand S, Santos A, Nohara LL, Harrison J, Norcross NR, Thompson S, Smith V, Lema C, Varela-Ramirez A, Gilbert IH, Almeida IC, Maldonado RA. Validation of N-myristoyltransferase as Potential Chemotherapeutic Target in Mammal-Dwelling Stages of Trypanosoma cruzi. PLoS Negl Trop Dis 2016; 10:e0004540. [PMID: 27128971 PMCID: PMC4851402 DOI: 10.1371/journal.pntd.0004540] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/22/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Trypanosoma cruzi causes Chagas disease, an endemic and debilitating illness in Latin America. Lately, owing to extensive population movements, this neglected tropical disease has become a global health concern. The two clinically available drugs for the chemotherapy of Chagas disease have rather high toxicity and limited efficacy in the chronic phase of the disease, and may induce parasite resistance. The development of new anti-T. cruzi agents is therefore imperative. The enzyme N-myristoyltransferase (NMT) has recently been biochemically characterized, shown to be essential in Leishmania major, Trypanosoma brucei, and T. cruzi¸ and proposed as promising chemotherapeutic target in these trypanosomatids. METHODOLOGY/PRINCIPAL FINDINGS Here, using high-content imaging we assayed eight known trypanosomatid NMT inhibitors, against mammal-dwelling intracellular amastigote and trypomastigote stages and demonstrated that three of them (compounds 1, 5, and 8) have potent anti-proliferative effect at submicromolar concentrations against T. cruzi, with very low toxicity against human epithelial cells. Moreover, metabolic labeling using myristic acid, azide showed a considerable decrease in the myristoylation of proteins in parasites treated with NMT inhibitors, providing evidence of the on-target activity of the inhibitors. CONCLUSIONS/SIGNIFICANCE Taken together, our data point out to the potential use of NMT inhibitors as anti-T. cruzi chemotherapy.
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Affiliation(s)
- Linda J. Herrera
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Stephen Brand
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Andres Santos
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Lilian L. Nohara
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Justin Harrison
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Neil R. Norcross
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Stephen Thompson
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Victoria Smith
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Carolina Lema
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Armando Varela-Ramirez
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Ian H. Gilbert
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Igor C. Almeida
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Rosa A. Maldonado
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
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Loureiro I, Faria J, Clayton C, Macedo-Ribeiro S, Santarém N, Roy N, Cordeiro-da-Siva A, Tavares J. Ribose 5-phosphate isomerase B knockdown compromises Trypanosoma brucei bloodstream form infectivity. PLoS Negl Trop Dis 2015; 9:e3430. [PMID: 25568941 PMCID: PMC4287489 DOI: 10.1371/journal.pntd.0003430] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/21/2014] [Indexed: 12/13/2022] Open
Abstract
Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive drug target waiting further characterization. In this study, Trypanosoma brucei ribose 5-phosphate isomerase B showed in vitro isomerase activity. RNAi against this enzyme reduced parasites' in vitro growth, and more importantly, bloodstream forms infectivity. Mice infected with induced RNAi clones exhibited lower parasitaemia and a prolonged survival compared to control mice. Phenotypic reversion was achieved by complementing induced RNAi clones with an ectopic copy of Trypanosoma cruzi gene. Our results present the first functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B, and show the relevance of an enzyme belonging to the non-oxidative branch of the pentose phosphate pathway in the context of Trypanosoma brucei infection. Within the non-oxidative branch of the pentose phosphate pathway, ribose 5-phosphate isomerase catalyzes the inter-conversion of ribose 5-phosphate and ribulose 5-phosphate. There are two types of ribose 5-phosphate isomerase, namely A and B. The presence of type B in Trypanosoma brucei, and its absence in humans, make this protein a promising drug target. African sleeping sickness is a serious parasitic disease that relies on limited chemotherapeutic options for control. In our study, a functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B is reported. Biochemical studies confirmed enzyme isomerase activity and its downregulation by RNAi affected mainly parasites infectivity in vivo. Overall this study shows that ribose 5-phosphate isomerase depletion is detrimental for parasites infectivity under host pressure.
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Affiliation(s)
- Inês Loureiro
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Joana Faria
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH cv Alliance, Heidelberg, Germany
| | - Sandra Macedo-Ribeiro
- Protein Crystallography Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Nuno Santarém
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Nilanjan Roy
- Ashok & Rita Patel Institute of Integrated Study & Research in Biotechnology & Allied Sciences, New Vallabh Vidyanagar, Dist-Anand, Gujarat, India
| | - Anabela Cordeiro-da-Siva
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Departamento de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
- * E-mail: (ACdS); (JT)
| | - Joana Tavares
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- * E-mail: (ACdS); (JT)
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Huang G, Vercesi AE, Docampo R. Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter. Nat Commun 2014; 4:2865. [PMID: 24305511 PMCID: PMC3868461 DOI: 10.1038/ncomms3865] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 11/04/2013] [Indexed: 01/07/2023] Open
Abstract
Mechanisms of regulation of mitochondrial metabolism in trypanosomes are not completely understood. Here we present evidence that the Trypanosoma brucei mitochondrial calcium uniporter (TbMCU) is essential for regulation of mitochondrial bioenergetics, autophagy, and cell death, even in the bloodstream forms that are devoid of a functional respiratory chain and oxidative phosphorylation. Localization studies reveal its co-localization with MitoTracker staining. TbMCU overexpression increases mitochondrial Ca2+ accumulation in intact and permeabilized trypanosomes, generates excessive mitochondrial reactive oxygen species (ROS), and sensitizes them to apoptotic stimuli. Ablation of TbMCU in RNAi or conditional knockout trypanosomes reduces mitochondrial Ca2+ uptake without affecting their membrane potential, increases the AMP/ATP ratio, stimulates autophagosome formation, and produces marked defects in growth in vitro and infectivity in mice, revealing its essentiality in these parasites. The requirement of TbMCU for proline and pyruvate metabolism in procyclic and bloodstream forms, respectively, reveals its role in regulation of mitochondrial bioenergetics.
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Affiliation(s)
- Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, USA
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Docampo R, Vercesi AE, Huang G. Mitochondrial calcium transport in trypanosomes. Mol Biochem Parasitol 2014; 196:108-16. [PMID: 25218432 DOI: 10.1016/j.molbiopara.2014.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/22/2014] [Accepted: 09/02/2014] [Indexed: 01/26/2023]
Abstract
The biochemical peculiarities of trypanosomes were fundamental for the recent molecular identification of the long-sought channel involved in mitochondrial Ca(2+) uptake, the mitochondrial Ca(2+) uniporter or MCU. This discovery led to the finding of numerous regulators of the channel, which form a high molecular weight complex with MCU. Some of these regulators have been bioinformatically identified in trypanosomes, which are the first eukaryotic organisms described for which MCU is essential. In trypanosomes MCU is important for buffering cytosolic Ca(2+) changes and for activation of the bioenergetics of the cells. Future work on this pathway in trypanosomes promises further insight into the biology of these fascinating eukaryotes, as well as the potential for novel target discovery.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA; Departamento de Patologia Clínica, State University of Campinas, Campinas 13083, SP, Brazil.
| | - Anibal E Vercesi
- Departamento de Patologia Clínica, State University of Campinas, Campinas 13083, SP, Brazil
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Uttaro AD. Acquisition and biosynthesis of saturated and unsaturated fatty acids by trypanosomatids. Mol Biochem Parasitol 2014; 196:61-70. [DOI: 10.1016/j.molbiopara.2014.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 03/28/2014] [Accepted: 04/01/2014] [Indexed: 12/21/2022]
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Mazet M, Morand P, Biran M, Bouyssou G, Courtois P, Daulouède S, Millerioux Y, Franconi JM, Vincendeau P, Moreau P, Bringaud F. Revisiting the central metabolism of the bloodstream forms of Trypanosoma brucei: production of acetate in the mitochondrion is essential for parasite viability. PLoS Negl Trop Dis 2013; 7:e2587. [PMID: 24367711 PMCID: PMC3868518 DOI: 10.1371/journal.pntd.0002587] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/30/2013] [Indexed: 11/24/2022] Open
Abstract
Background The bloodstream forms of Trypanosoma brucei, the causative agent of sleeping sickness, rely solely on glycolysis for ATP production. It is generally accepted that pyruvate is the major end-product excreted from glucose metabolism by the proliferative long-slender bloodstream forms of the parasite, with virtually no production of succinate and acetate, the main end-products excreted from glycolysis by all the other trypanosomatid adaptative forms, including the procyclic insect form of T. brucei. Methodology/Principal Findings A comparative NMR analysis showed that the bloodstream long-slender and procyclic trypanosomes excreted equivalent amounts of acetate and succinate from glucose metabolism. Key enzymes of acetate production from glucose-derived pyruvate and threonine are expressed in the mitochondrion of the long-slender forms, which produces 1.4-times more acetate from glucose than from threonine in the presence of an equal amount of both carbon sources. By using a combination of reverse genetics and NMR analyses, we showed that mitochondrial production of acetate is essential for the long-slender forms, since blocking of acetate biosynthesis from both carbon sources induces cell death. This was confirmed in the absence of threonine by the lethal phenotype of RNAi-mediated depletion of the pyruvate dehydrogenase, which is involved in glucose-derived acetate production. In addition, we showed that de novo fatty acid biosynthesis from acetate is essential for this parasite, as demonstrated by a lethal phenotype and metabolic analyses of RNAi-mediated depletion of acetyl-CoA synthetase, catalyzing the first cytosolic step of this pathway. Conclusions/Significance Acetate produced in the mitochondrion from glucose and threonine is synthetically essential for the long-slender mammalian forms of T. brucei to feed the essential fatty acid biosynthesis through the “acetate shuttle” that was recently described in the procyclic insect form of the parasite. Consequently, key enzymatic steps of this pathway, particularly acetyl-CoA synthetase, constitute new attractive drug targets against trypanosomiasis. Many protists, including parasitic helminthes, trichomonads and trypanosomatids, produce acetate in their mitochondrion or mitochondrion-like organelle, which is excreted as a main metabolic end-product of their energy metabolism. We have recently demonstrated that mitochondrial production of acetate is essential for fatty acid biosynthesis and ATP production in the procyclic insect form of T. brucei. However, acetate metabolism has not been investigated in the long-slender bloodstream forms of the parasite, the proliferative forms responsible for the sleeping sickness. In contrast to the current view, we showed that the bloodstream forms produce almost as much acetate from glucose than the procyclic parasites. Acetate production from glucose and threonine is synthetically essential for growth and de novo synthesis of fatty acids of the bloodstream trypanosomes. These data highlight that the central metabolism of the bloodstream forms contains unexpected essential pathways, although minor in terms of metabolic flux, which could be targeted for the development of trypanocidal drugs.
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Affiliation(s)
- Muriel Mazet
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Pauline Morand
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Marc Biran
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Guillaume Bouyssou
- Laboratoire de Biogenèse Membranaire, UMR5200 Université Bordeaux Segalen, CNRS, Bâtiment A3, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Pierrette Courtois
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Sylvie Daulouède
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Yoann Millerioux
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Jean-Michel Franconi
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Philippe Vincendeau
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Patrick Moreau
- Laboratoire de Biogenèse Membranaire, UMR5200 Université Bordeaux Segalen, CNRS, Bâtiment A3, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
- * E-mail: .
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Millerioux Y, Ebikeme C, Biran M, Morand P, Bouyssou G, Vincent IM, Mazet M, Riviere L, Franconi JM, Burchmore RJS, Moreau P, Barrett MP, Bringaud F. The threonine degradation pathway of the Trypanosoma brucei procyclic form: the main carbon source for lipid biosynthesis is under metabolic control. Mol Microbiol 2013; 90:114-29. [PMID: 23899193 PMCID: PMC4034587 DOI: 10.1111/mmi.12351] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2013] [Indexed: 12/21/2022]
Abstract
The Trypanosoma brucei procyclic form resides within the digestive tract of its insect vector, where it exploits amino acids as carbon sources. Threonine is the amino acid most rapidly consumed by this parasite, however its role is poorly understood. Here, we show that the procyclic trypanosomes grown in rich medium only use glucose and threonine for lipid biosynthesis, with threonine's contribution being ∼ 2.5 times higher than that of glucose. A combination of reverse genetics and NMR analysis of excreted end-products from threonine and glucose metabolism, shows that acetate, which feeds lipid biosynthesis, is also produced primarily from threonine. Interestingly, the first enzymatic step of the threonine degradation pathway, threonine dehydrogenase (TDH, EC 1.1.1.103), is under metabolic control and plays a key role in the rate of catabolism. Indeed, a trypanosome mutant deleted for the phosphoenolpyruvate decarboxylase gene (PEPCK, EC 4.1.1.49) shows a 1.7-fold and twofold decrease of TDH protein level and activity, respectively, associated with a 1.8-fold reduction in threonine-derived acetate production. We conclude that TDH expression is under control and can be downregulated in response to metabolic perturbations, such as in the PEPCK mutant in which the glycolytic metabolic flux was redirected towards acetate production.
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Affiliation(s)
- Yoann Millerioux
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR-5536 Université Bordeaux Segalen, CNRS, 146 rue Léo Saignat, 33076, Bordeaux, France
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Lipid synthesis in protozoan parasites: a comparison between kinetoplastids and apicomplexans. Prog Lipid Res 2013; 52:488-512. [PMID: 23827884 DOI: 10.1016/j.plipres.2013.06.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 12/22/2022]
Abstract
Lipid metabolism is of crucial importance for pathogens. Lipids serve as cellular building blocks, signalling molecules, energy stores, posttranslational modifiers, and pathogenesis factors. Parasites rely on a complex system of uptake and synthesis mechanisms to satisfy their lipid needs. The parameters of this system change dramatically as the parasite transits through the various stages of its life cycle. Here we discuss the tremendous recent advances that have been made in the understanding of the synthesis and uptake pathways for fatty acids and phospholipids in apicomplexan and kinetoplastid parasites, including Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania. Lipid synthesis differs in significant ways between parasites from both phyla and the human host. Parasites have acquired novel pathways through endosymbiosis, as in the case of the apicoplast, have dramatically reshaped substrate and product profiles, and have evolved specialized lipids to interact with or manipulate the host. These differences potentially provide opportunities for drug development. We outline the lipid pathways for key species in detail as they progress through the developmental cycle and highlight those that are of particular importance to the biology of the pathogens and/or are the most promising targets for parasite-specific treatment.
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Vigueira PA, Ray SS, Martin BA, Ligon MM, Paul KS. Effects of the green tea catechin (-)-epigallocatechin gallate on Trypanosoma brucei. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:225-9. [PMID: 24533284 DOI: 10.1016/j.ijpddr.2012.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/11/2012] [Accepted: 09/13/2012] [Indexed: 12/11/2022]
Abstract
The current pharmacopeia to treat the lethal human and animal diseases caused by the protozoan parasite Trypanosoma brucei remains limited. The parasite's ability to undergo antigenic variation represents a considerable barrier to vaccine development, making the identification of new drug targets extremely important. Recent studies have demonstrated that fatty acid synthesis is important for growth and virulence of Trypanosoma brucei brucei, suggesting this pathway may have therapeutic potential. The first committed step of fatty acid synthesis is catalyzed by acetyl-CoA carboxylase (ACC), which is a known target of (-)-epigallocatechin-3-gallate (EGCG), an active polyphenol compound found in green tea. EGCG exerts its effects on ACC through activation of AMP-dependent protein kinase, which phosphorylates and inhibits ACC. We found that EGCG inhibited TbACC activity with an EC50 of 37 μM and 55 μM for bloodstream form and procyclic form lysates, respectively. Treatment with 100 μM EGCG induced a 4.7- and 1.7- fold increase in TbACC phosphorylation in bloodstream form and procyclic lysates. EGCG also inhibited the growth of bloodstream and procyclic parasites in culture, with a 48 h EC50 of 33 μM and 27 μM, respectively, which is greater than the EGCG plasma levels typically achievable in humans through oral dosing. Daily intraperitoneal administration of EGCG did not reduce the virulence of an acute mouse model of T. b. brucei infection. These data suggest a reduced potential for EGCG to treat T. brucei infections, but suggest that EGCG may prove to be useful as a tool to probe ACC regulation.
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Affiliation(s)
- Patrick A Vigueira
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Sunayan S Ray
- Department of Genetics & Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Ben A Martin
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Marianne M Ligon
- Department of Genetics & Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Kimberly S Paul
- Department of Genetics & Biochemistry, Clemson University, Clemson, SC 29634, USA
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16
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Structure and function of biotin-dependent carboxylases. Cell Mol Life Sci 2012; 70:863-91. [PMID: 22869039 DOI: 10.1007/s00018-012-1096-0] [Citation(s) in RCA: 254] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/07/2012] [Accepted: 07/09/2012] [Indexed: 12/14/2022]
Abstract
Biotin-dependent carboxylases include acetyl-CoA carboxylase (ACC), propionyl-CoA carboxylase (PCC), 3-methylcrotonyl-CoA carboxylase (MCC), geranyl-CoA carboxylase, pyruvate carboxylase (PC), and urea carboxylase (UC). They contain biotin carboxylase (BC), carboxyltransferase (CT), and biotin-carboxyl carrier protein components. These enzymes are widely distributed in nature and have important functions in fatty acid metabolism, amino acid metabolism, carbohydrate metabolism, polyketide biosynthesis, urea utilization, and other cellular processes. ACCs are also attractive targets for drug discovery against type 2 diabetes, obesity, cancer, microbial infections, and other diseases, and the plastid ACC of grasses is the target of action of three classes of commercial herbicides. Deficiencies in the activities of PCC, MCC, or PC are linked to serious diseases in humans. Our understanding of these enzymes has been greatly enhanced over the past few years by the crystal structures of the holoenzymes of PCC, MCC, PC, and UC. The structures reveal unanticipated features in the architectures of the holoenzymes, including the presence of previously unrecognized domains, and provide a molecular basis for understanding their catalytic mechanism as well as the large collection of disease-causing mutations in PCC, MCC, and PC. This review will summarize the recent advances in our knowledge on the structure and function of these important metabolic enzymes.
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Haanstra JR, van Tuijl A, van Dam J, van Winden W, Tielens AGM, van Hellemond JJ, Bakker BM. Proliferating bloodstream-form Trypanosoma brucei use a negligible part of consumed glucose for anabolic processes. Int J Parasitol 2012; 42:667-73. [PMID: 22580731 DOI: 10.1016/j.ijpara.2012.04.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/13/2012] [Accepted: 04/18/2012] [Indexed: 10/28/2022]
Abstract
Our quantitative knowledge of carbon fluxes in the long slender bloodstream form (BSF) Trypanosoma brucei is mainly based on non-proliferating parasites, isolated from laboratory animals and kept in buffers. In this paper we present a carbon balance for exponentially growing bloodstream form trypanosomes. The cells grew with a doubling time of 5.3h, contained 46 μ mol of carbon (10(8) cells)(-1) and had a glucose consumption flux of 160 nmol min(-1) (10(8) cells)(-1). The molar ratio of pyruvate excreted versus glucose consumed was 2.1. Furthermore, analysis of the (13)C label distribution in pyruvate in (13)C-glucose incubations of exponentially growing trypanosomes showed that glucose was the sole substrate for pyruvate production. We conclude that the glucose metabolised in glycolysis was hardly, if at all, used for biosynthetic processes. Carbon flux through glycolysis in exponentially growing trypanosomes was 10 times higher than the incorporation of carbon into biomass. This biosynthetic carbon is derived from other precursors present in the nutrient rich growth medium. Furthermore, we found that the glycolytic flux was unaltered when the culture went into stationary phase, suggesting that most of the ATP produced in glycolysis is used for processes other than growth.
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Affiliation(s)
- Jurgen R Haanstra
- Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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Vigueira PA, Paul KS. Trypanosoma brucei: inhibition of acetyl-CoA carboxylase by haloxyfop. Exp Parasitol 2011; 130:159-65. [PMID: 22119241 DOI: 10.1016/j.exppara.2011.10.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/08/2011] [Accepted: 10/31/2011] [Indexed: 10/15/2022]
Abstract
Trypanosoma brucei, a eukaryotic pathogen that causes African sleeping sickness in humans and nagana in cattle, depends on the enzyme acetyl-CoA carboxylase (ACC) for full virulence in mice. ACC produces malonyl-CoA, the two carbon donor for fatty acid synthesis. We assessed the effect of haloxyfop, an aryloxyphenoxypropionate herbicide inhibitor of plastid ACCs in many plants as well as Toxoplasma gondii, on T. brucei ACC activity and growth in culture. Haloxyfop inhibited TbACC in cell lysate (EC(50) 67 μM), despite the presence of an amino acid motif typically associated with resistance. Haloxyfop also reduced growth of bloodstream and procyclic form parasites (EC(50) of 0.8 and 1.2 mM). However, the effect on growth was likely due to off-target effects because haloxyfop treatment had no effect on fatty acid elongation or incorporation into complex lipids in vivo.
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Affiliation(s)
- Patrick A Vigueira
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA.
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Barry RM, Gitai Z. Self-assembling enzymes and the origins of the cytoskeleton. Curr Opin Microbiol 2011; 14:704-11. [PMID: 22014508 DOI: 10.1016/j.mib.2011.09.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 09/23/2011] [Accepted: 09/29/2011] [Indexed: 12/22/2022]
Abstract
The bacterial cytoskeleton is composed of a complex and diverse group of proteins that self-assemble into linear filaments. These filaments support and organize cellular architecture and provide a dynamic network controlling transport and localization within the cell. Here, we review recent discoveries related to a newly appreciated class of self-assembling proteins that expand our view of the bacterial cytoskeleton and provide potential explanations for its evolutionary origins. Specifically, several types of metabolic enzymes can form structures similar to established cytoskeletal filaments and, in some cases, these structures have been repurposed for structural uses independent of their normal roles. The behaviors of these enzymes suggest that some modern cytoskeletal proteins may have evolved from dual-role proteins with catalytic and structural functions.
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Affiliation(s)
- Rachael M Barry
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States
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