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Hierro-Yap C, Šubrtová K, Gahura O, Panicucci B, Dewar C, Chinopoulos C, Schnaufer A, Zíková A. Bioenergetic consequences of F oF 1-ATP synthase/ATPase deficiency in two life cycle stages of Trypanosoma brucei. J Biol Chem 2021; 296:100357. [PMID: 33539923 PMCID: PMC7949148 DOI: 10.1016/j.jbc.2021.100357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/23/2020] [Accepted: 01/28/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial ATP synthase is a reversible nanomotor synthesizing or hydrolyzing ATP depending on the potential across the membrane in which it is embedded. In the unicellular parasite Trypanosoma brucei, the direction of the complex depends on the life cycle stage of this digenetic parasite: in the midgut of the tsetse fly vector (procyclic form), the FoF1–ATP synthase generates ATP by oxidative phosphorylation, whereas in the mammalian bloodstream form, this complex hydrolyzes ATP and maintains mitochondrial membrane potential (ΔΨm). The trypanosome FoF1–ATP synthase contains numerous lineage-specific subunits whose roles remain unknown. Here, we seek to elucidate the function of the lineage-specific protein Tb1, the largest membrane-bound subunit. In procyclic form cells, Tb1 silencing resulted in a decrease of FoF1–ATP synthase monomers and dimers, rerouting of mitochondrial electron transfer to the alternative oxidase, reduced growth rate and cellular ATP levels, and elevated ΔΨm and total cellular reactive oxygen species levels. In bloodstream form parasites, RNAi silencing of Tb1 by ∼90% resulted in decreased FoF1–ATPase monomers and dimers, but it had no apparent effect on growth. The same findings were obtained by silencing of the oligomycin sensitivity-conferring protein, a conserved subunit in T. brucei FoF1–ATP synthase. However, as expected, nearly complete Tb1 or oligomycin sensitivity-conferring protein suppression was lethal because of the inability to sustain ΔΨm. The diminishment of FoF1–ATPase complexes was further accompanied by a decreased ADP/ATP ratio and reduced oxygen consumption via the alternative oxidase. Our data illuminate the often diametrically opposed bioenergetic consequences of FoF1–ATP synthase loss in insect versus mammalian forms of the parasite.
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Affiliation(s)
- Carolina Hierro-Yap
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Karolína Šubrtová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Caroline Dewar
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | | | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.
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Colina-Tenorio L, Miranda-Astudillo H, Dautant A, Vázquez-Acevedo M, Giraud MF, González-Halphen D. Subunit Asa3 ensures the attachment of the peripheral stalk to the membrane sector of the dimeric ATP synthase of Polytomella sp. Biochem Biophys Res Commun 2018; 509:341-347. [PMID: 30585150 DOI: 10.1016/j.bbrc.2018.12.142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 12/19/2018] [Indexed: 02/04/2023]
Abstract
The mitochondrial ATP synthase of Polytomella exhibits a peripheral stalk and a dimerization domain built by the Asa subunits, unique to chlorophycean algae. The topology of these subunits has been extensively studied. Here we explored the interactions of subunit Asa3 using Far Western blotting and subcomplex reconstitution, and found it associates with Asa1 and Asa8. We also identified the novel interactions Asa1-Asa2 and Asa1-Asa7. In silico analyses of Asa3 revealed that it adopts a HEAT repeat-like structure that points to its location within the enzyme based on the available 3D-map of the algal ATP synthase. We suggest that subunit Asa3 is instrumental in securing the attachment of the peripheral stalk to the membrane sector, thus stabilizing the dimeric mitochondrial ATP synthase.
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Affiliation(s)
- Lilia Colina-Tenorio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Alain Dautant
- CNRS, UMR5095, IBGC, Bordeaux, France; Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Miriam Vázquez-Acevedo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Marie-France Giraud
- CNRS, UMR5095, IBGC, Bordeaux, France; Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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Colina-Tenorio L, Dautant A, Miranda-Astudillo H, Giraud MF, González-Halphen D. The Peripheral Stalk of Rotary ATPases. Front Physiol 2018; 9:1243. [PMID: 30233414 PMCID: PMC6131620 DOI: 10.3389/fphys.2018.01243] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/16/2018] [Indexed: 12/18/2022] Open
Abstract
Rotary ATPases are a family of enzymes that are thought of as molecular nanomotors and are classified in three types: F, A, and V-type ATPases. Two members (F and A-type) can synthesize and hydrolyze ATP, depending on the energetic needs of the cell, while the V-type enzyme exhibits only a hydrolytic activity. The overall architecture of all these enzymes is conserved and three main sectors are distinguished: a catalytic core, a rotor and a stator or peripheral stalk. The peripheral stalks of the A and V-types are highly conserved in both structure and function, however, the F-type peripheral stalks have divergent structures. Furthermore, the peripheral stalk has other roles beyond its stator function, as evidenced by several biochemical and recent structural studies. This review describes the information regarding the organization of the peripheral stalk components of F, A, and V-ATPases, highlighting the key differences between the studied enzymes, as well as the different processes in which the structure is involved.
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Affiliation(s)
- Lilia Colina-Tenorio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Alain Dautant
- CNRS, UMR5095, IBGC, Bordeaux, France.,Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Héctor Miranda-Astudillo
- Genetics and Physiology of Microalgae, InBios, PhytoSYSTEMS, University of Liège, Liège, Belgium
| | - Marie-France Giraud
- CNRS, UMR5095, IBGC, Bordeaux, France.,Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Miranda-Astudillo H, Colina-Tenorio L, Jiménez-Suárez A, Vázquez-Acevedo M, Salin B, Giraud MF, Remacle C, Cardol P, González-Halphen D. Oxidative phosphorylation supercomplexes and respirasome reconstitution of the colorless alga Polytomella sp. Biochim Biophys Acta Bioenerg 2018. [PMID: 29540299 DOI: 10.1016/j.bbabio.2018.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The proposal that the respiratory complexes can associate with each other in larger structures named supercomplexes (SC) is generally accepted. In the last decades most of the data about this association came from studies in yeasts, mammals and plants, and information is scarce in other lineages. Here we studied the supramolecular association of the F1FO-ATP synthase (complex V) and the respiratory complexes I, III and IV of the colorless alga Polytomella sp. with an approach that involves solubilization using mild detergents, n-dodecyl-β-D-maltoside (DDM) or digitonin, followed by separation of native protein complexes by electrophoresis (BN-PAGE), after which we identified oligomeric forms of complex V (mainly V2 and V4) and different respiratory supercomplexes (I/IV6, I/III4, I/IV). In addition, purification/reconstitution of the supercomplexes by anion exchange chromatography was also performed. The data show that these complexes have the ability to strongly associate with each other and form DDM-stable macromolecular structures. The stable V4 ATPase oligomer was observed by electron-microscopy and the association of the respiratory complexes in the so-called "respirasome" was able to perform in-vitro oxygen consumption.
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Affiliation(s)
- Héctor Miranda-Astudillo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico; Genetics and Physiology of microalgae, InBioS/Phytosystems, University of Liège, Belgium.
| | - Lilia Colina-Tenorio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
| | - Alejandra Jiménez-Suárez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
| | - Miriam Vázquez-Acevedo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
| | - Bénédicte Salin
- CNRS, UMR5095, IBGC, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France; Université de Bordeaux, Campus Carreire, 146 Rue Léo Saignat, 33077 Bordeaux, France
| | - Marie-France Giraud
- CNRS, UMR5095, IBGC, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France; Université de Bordeaux, Campus Carreire, 146 Rue Léo Saignat, 33077 Bordeaux, France
| | - Claire Remacle
- Genetics and Physiology of microalgae, InBioS/Phytosystems, University of Liège, Belgium
| | - Pierre Cardol
- Genetics and Physiology of microalgae, InBioS/Phytosystems, University of Liège, Belgium
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
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Jiménez-Suárez A, Vázquez-Acevedo M, Miranda-Astudillo H, González-Halphen D. Cox2A/Cox2B subunit interaction in Polytomella sp. cytochrome c oxidase: role of the Cox2B subunit extension. J Bioenerg Biomembr 2017; 49:453-61. [PMID: 29043530 DOI: 10.1007/s10863-017-9728-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/22/2017] [Indexed: 10/18/2022]
Abstract
Subunit II of cytochrome c oxidase (Cox2) is usually encoded in the mitochondrial genome, synthesized in the organelle, inserted co-translationally into the inner mitochondrial membrane, and assembled into the respiratory complex. In chlorophycean algae however, the cox2 gene was split into the cox2a and cox2b genes, and in some algal species like Chlamydomonas reinhardtii and Polytomella sp. both fragmented genes migrated to the nucleus. The corresponding Cox2A and Cox2B subunits are imported into mitochondria forming a heterodimeric Cox2 subunit. When comparing the sequences of chlorophycean Cox2A and Cox2B proteins with orthodox Cox2 subunits, a C-terminal extension in Cox2A and an N-terminal extension in Cox2B were identified. It was proposed that these extensions favor the Cox2A/Cox2B interaction. In vitro studies carried out in this work suggest that the removal of the Cox2B extension only partially affects binding of Cox2B to Cox2A. We conclude that this extension is dispensable, but when present it weakly reinforces the Cox2A/Cox2B interaction.
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Sánchez-Vásquez L, Vázquez-Acevedo M, de la Mora J, Vega-deLuna F, Cardol P, Remacle C, Dreyfus G, González-Halphen D. Near-neighbor interactions of the membrane-embedded subunits of the mitochondrial ATP synthase of a chlorophycean alga. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2017; 1858:497-509. [DOI: 10.1016/j.bbabio.2017.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/25/2017] [Accepted: 04/29/2017] [Indexed: 12/24/2022]
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Yadav KS, Miranda-Astudillo HV, Colina-Tenorio L, Bouillenne F, Degand H, Morsomme P, González-Halphen D, Boekema EJ, Cardol P. Atypical composition and structure of the mitochondrial dimeric ATP synthase from Euglena gracilis. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2017; 1858:267-275. [DOI: 10.1016/j.bbabio.2017.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/22/2016] [Accepted: 01/10/2017] [Indexed: 11/26/2022]
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Colina-Tenorio L, Miranda-Astudillo H, Cano-Estrada A, Vázquez-Acevedo M, Cardol P, Remacle C, González-Halphen D. Subunit Asa1 spans all the peripheral stalk of the mitochondrial ATP synthase of the chlorophycean alga Polytomella sp. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2016; 1857:359-69. [DOI: 10.1016/j.bbabio.2015.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/23/2015] [Accepted: 11/27/2015] [Indexed: 11/26/2022]
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Vázquez-Acevedo M, Vega-deLuna F, Sánchez-Vásquez L, Colina-Tenorio L, Remacle C, Cardol P, Miranda-Astudillo H, González-Halphen D. Dissecting the peripheral stalk of the mitochondrial ATP synthase of chlorophycean algae. Biochim Biophys Acta 2016; 1857:1183-1190. [PMID: 26873638 DOI: 10.1016/j.bbabio.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/25/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
The algae Chlamydomonas reinhardtii and Polytomella sp., a green and a colorless member of the chlorophycean lineage respectively, exhibit a highly-stable dimeric mitochondrial F1Fo-ATP synthase (complex V), with a molecular mass of 1600 kDa. Polytomella, lacking both chloroplasts and a cell wall, has greatly facilitated the purification of the algal ATP-synthase. Each monomer of the enzyme has 17 polypeptides, eight of which are the conserved, main functional components, and nine polypeptides (Asa1 to Asa9) unique to chlorophycean algae. These atypical subunits form the two robust peripheral stalks observed in the highly-stable dimer of the algal ATP synthase in several electron-microscopy studies. The topological disposition of the components of the enzyme has been addressed with cross-linking experiments in the isolated complex; generation of subcomplexes by limited dissociation of complex V; detection of subunit-subunit interactions using recombinant subunits; in vitro reconstitution of subcomplexes; silencing of the expression of Asa subunits; and modeling of the overall structural features of the complex by EM image reconstruction. Here, we report that the amphipathic polymer Amphipol A8-35 partially dissociates the enzyme, giving rise to two discrete dimeric subcomplexes, whose compositions were characterized. An updated model for the topological disposition of the 17 polypeptides that constitute the algal enzyme is suggested. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Miriam Vázquez-Acevedo
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Félix Vega-deLuna
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Lorenzo Sánchez-Vásquez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Lilia Colina-Tenorio
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Claire Remacle
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Pierre Cardol
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Héctor Miranda-Astudillo
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Diego González-Halphen
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico.
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Lee J, Ding S, Walpole TB, Holding AN, Montgomery MG, Fearnley IM, Walker JE. Organization of Subunits in the Membrane Domain of the Bovine F-ATPase Revealed by Covalent Cross-linking. J Biol Chem 2015; 290:13308-20. [PMID: 25851905 PMCID: PMC4505582 DOI: 10.1074/jbc.m115.645283] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Indexed: 12/21/2022] Open
Abstract
The F-ATPase in bovine mitochondria is a membrane-bound complex of about 30 subunits of 18 different kinds. Currently, ∼85% of its structure is known. The enzyme has a membrane extrinsic catalytic domain, and a membrane intrinsic domain where the turning of the enzyme's rotor is generated from the transmembrane proton-motive force. The domains are linked by central and peripheral stalks. The central stalk and a hydrophobic ring of c-subunits in the membrane domain constitute the enzyme's rotor. The external surface of the catalytic domain and membrane subunit a are linked by the peripheral stalk, holding them static relative to the rotor. The membrane domain contains six additional subunits named ATP8, e, f, g, DAPIT (diabetes-associated protein in insulin-sensitive tissues), and 6.8PL (6.8-kDa proteolipid), each with a single predicted transmembrane α-helix, but their orientation and topography are unknown. Mutations in ATP8 uncouple the enzyme and interfere with its assembly, but its roles and the roles of the other five subunits are largely unknown. We have reacted accessible amino groups in the enzyme with bifunctional cross-linking agents and identified the linked residues. Cross-links involving the supernumerary subunits, where the structures are not known, show that the C terminus of ATP8 extends ∼70 Å from the membrane into the peripheral stalk and that the N termini of the other supernumerary subunits are on the same side of the membrane, probably in the mitochondrial matrix. These experiments contribute significantly toward building up a complete structural picture of the F-ATPase.
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Affiliation(s)
- Jennifer Lee
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - ShuJing Ding
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - Thomas B Walpole
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - Andrew N Holding
- The Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Martin G Montgomery
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - Ian M Fearnley
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - John E Walker
- From the The Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
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Šubrtová K, Panicucci B, Zíková A. ATPaseTb2, a unique membrane-bound FoF1-ATPase component, is essential in bloodstream and dyskinetoplastic trypanosomes. PLoS Pathog 2015; 11:e1004660. [PMID: 25714685 PMCID: PMC4340940 DOI: 10.1371/journal.ppat.1004660] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 01/06/2015] [Indexed: 12/21/2022] Open
Abstract
In the infectious stage of Trypanosoma brucei, an important parasite of humans and livestock, the mitochondrial (mt) membrane potential (Δψm) is uniquely maintained by the ATP hydrolytic activity and subsequent proton pumping of the essential FoF1-ATPase. Intriguingly, this multiprotein complex contains several trypanosome-specific subunits of unknown function. Here, we demonstrate that one of the largest novel subunits, ATPaseTb2, is membrane-bound and localizes with monomeric and multimeric assemblies of the FoF1-ATPase. Moreover, RNAi silencing of ATPaseTb2 quickly leads to a significant decrease of the Δψm that manifests as a decreased growth phenotype, indicating that the FoF1-ATPase is impaired. To further explore the function of this protein, we employed a trypanosoma strain that lacks mtDNA (dyskinetoplastic, Dk) and thus subunit a, an essential component of the proton pore in the membrane Fo-moiety. These Dk cells generate the Δψm by combining the hydrolytic activity of the matrix-facing F1-ATPase and the electrogenic exchange of ATP4- for ADP3- by the ATP/ADP carrier (AAC). Surprisingly, in addition to the expected presence of F1-ATPase, the monomeric and multimeric FoF1-ATPase complexes were identified. In fact, the immunoprecipitation of a F1-ATPase subunit demonstrated that ATPaseTb2 was a component of these complexes. Furthermore, RNAi studies established that the membrane-bound ATPaseTb2 subunit is essential for maintaining normal growth and the Δψm of Dk cells. Thus, even in the absence of subunit a, a portion of the FoF1-ATPase is assembled in Dk cells.
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Affiliation(s)
- Karolína Šubrtová
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, CAS, České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Nawrocki WJ, Tourasse NJ, Taly A, Rappaport F, Wollman FA. The plastid terminal oxidase: its elusive function points to multiple contributions to plastid physiology. Annu Rev Plant Biol 2015; 66:49-74. [PMID: 25580838 DOI: 10.1146/annurev-arplant-043014-114744] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plastids have retained from their cyanobacterial ancestor a fragment of the respiratory electron chain comprising an NADPH dehydrogenase and a diiron oxidase, which sustain the so-called chlororespiration pathway. Despite its very low turnover rates compared with photosynthetic electron flow, knocking out the plastid terminal oxidase (PTOX) in plants or microalgae leads to severe phenotypes that encompass developmental and growth defects together with increased photosensitivity. On the basis of a phylogenetic and structural analysis of the enzyme, we discuss its physiological contribution to chloroplast metabolism, with an emphasis on its critical function in setting the redox poise of the chloroplast stroma in darkness. The emerging picture of PTOX is that of an enzyme at the crossroads of a variety of metabolic processes, such as, among others, the regulation of cyclic electron transfer and carotenoid biosynthesis, which have in common their dependence on the redox state of the plastoquinone pool, set largely by the activity of PTOX in darkness.
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Affiliation(s)
- Wojciech J Nawrocki
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, UMR 7141, Centre National de la Recherche Scientifique-Université Pierre et Marie Curie
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