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Hoh D, Froehlich JE, Kramer DM. Redox regulation in chloroplast thylakoid lumen: The pmf changes everything, again. PLANT, CELL & ENVIRONMENT 2024; 47:2749-2765. [PMID: 38111217 DOI: 10.1111/pce.14789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023]
Abstract
Photosynthesis is the foundation of life on Earth. However, if not well regulated, it can also generate excessive reactive oxygen species (ROS), which can cause photodamage. Regulation of photosynthesis is highly dynamic, responding to both environmental and metabolic cues, and occurs at many levels, from light capture to energy storage and metabolic processes. One general mechanism of regulation involves the reversible oxidation and reduction of protein thiol groups, which can affect the activity of enzymes and the stability of proteins. Such redox regulation has been well studied in stromal enzymes, but more recently, evidence has emerged of redox control of thylakoid lumenal enzymes. This review/hypothesis paper summarizes the latest research and discusses several open questions and challenges to achieving effective redox control in the lumen, focusing on the distinct environments and regulatory components of the thylakoid lumen, including the need to transport electrons across the thylakoid membrane, the effects of pH changes by the proton motive force (pmf) in the stromal and lumenal compartments, and the observed differences in redox states. These constraints suggest that activated oxygen species are likely to be major regulatory contributors to lumenal thiol redox regulation, with key components and processes yet to be discovered.
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Affiliation(s)
- Donghee Hoh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - John E Froehlich
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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Wu J, Rong L, Lin W, Kong L, Wei D, Zhang L, Rochaix JD, Xu X. Functional redox links between lumen thiol oxidoreductase1 and serine/threonine-protein kinase STN7. PLANT PHYSIOLOGY 2021; 186:964-976. [PMID: 33620491 PMCID: PMC8195503 DOI: 10.1093/plphys/kiab091] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/11/2021] [Indexed: 05/07/2023]
Abstract
In response to changing light quantity and quality, photosynthetic organisms perform state transitions, a process which optimizes photosynthetic yield and mitigates photo-damage. The serine/threonine-protein kinase STN7 phosphorylates the light-harvesting complex of photosystem II (PSII; light-harvesting complex II), which then migrates from PSII to photosystem I (PSI), thereby rebalancing the light excitation energy between the photosystems and restoring the redox poise of the photosynthetic electron transport chain. Two conserved cysteines forming intra- or intermolecular disulfide bonds in the lumenal domain (LD) of STN7 are essential for the kinase activity although it is still unknown how activation of the kinase is regulated. In this study, we show lumen thiol oxidoreductase 1 (LTO1) is co-expressed with STN7 in Arabidopsis (Arabidopsis thaliana) and interacts with the LD of STN7 in vitro and in vivo. LTO1 contains thioredoxin (TRX)-like and vitamin K epoxide reductase domains which are related to the disulfide-bond formation system in bacteria. We further show that the TRX-like domain of LTO1 is able to oxidize the conserved lumenal cysteines of STN7 in vitro. In addition, loss of LTO1 affects the kinase activity of STN7 in Arabidopsis. Based on these results, we propose that LTO1 helps to maintain STN7 in an oxidized active state in state 2 through redox interactions between the lumenal cysteines of STN7 and LTO1.
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Affiliation(s)
- Jianghao Wu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liwei Rong
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weijun Lin
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingxi Kong
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dengjie Wei
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jean-David Rochaix
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- Department of Molecular Biology, University of Geneva, Geneva 1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva 1211, Switzerland
| | - Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- Author for communication:
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Chin-Fatt A, Menassa R. A V HH-Fc Fusion Targeted to the Chloroplast Thylakoid Lumen Assembles and Neutralizes Enterohemorrhagic E. coli O157:H7. FRONTIERS IN PLANT SCIENCE 2021; 12:686421. [PMID: 34122494 PMCID: PMC8193579 DOI: 10.3389/fpls.2021.686421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Chimeric fusion proteins comprising a single domain antibody (VHH) fused to a crystallizable fragment (Fc) of an immunoglobulin are modular glycoproteins that are becoming increasingly in demand because of their value as diagnostics, research reagents and passive immunization therapeutics. Because ER-associated degradation and misfolding may potentially be limiting factors in the oxidative folding of VHH-Fc fusion proteins in the ER, we sought to explore oxidative folding in an alternative sub-compartment, the chloroplast thylakoid lumen, and determine its viability in a molecular farming context. We developed a set of in-house expression vectors for transient transformation of Nicotiana benthamiana leaves that target a VHH-Fc to the thylakoid lumen via either secretory (Sec) or twin-arginine translocation (Tat) import pathways. Compared to stromal [6.63 ± 3.41 mg/kg fresh weight (FW)], cytoplasmic (undetectable) and Tat-import pathways (5.43 ± 2.41 mg/kg FW), the Sec-targeted VHH-Fc showed superior accumulation (30.56 ± 5.19 mg/kg FW), but was less than that of the ER (51.16 ± 9.11 mg/kg FW). Additionally, the introduction of a rationally designed de novo disulfide bond enhances in planta accumulation when introduced into the Sec-targeted Fc fusion protein from 50.24 ± 4.08 mg/kg FW to 110.90 ± 6.46 mg/kg FW. In vitro immunofluorescent labeling assays on VHH-Fc purified from Sec, Tat, and stromal pathways demonstrate that the antibody still retains VHH functionality in binding Escherichia coli O157:H7 and neutralizing its intimate adherence to human epithelial type 2 cells. These results overall provide a proof of concept that the oxidative folding environment of the thylakoid lumen may be a viable compartment for stably folding disulfide-containing recombinant VHH-Fc proteins.
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Affiliation(s)
- Adam Chin-Fatt
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON, Canada
- Department of Biology, University of Western Ontario, London, ON, Canada
| | - Rima Menassa
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON, Canada
- Department of Biology, University of Western Ontario, London, ON, Canada
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Soma S, Morgada MN, Naik MT, Boulet A, Roesler AA, Dziuba N, Ghosh A, Yu Q, Lindahl PA, Ames JB, Leary SC, Vila AJ, Gohil VM. COA6 Is Structurally Tuned to Function as a Thiol-Disulfide Oxidoreductase in Copper Delivery to Mitochondrial Cytochrome c Oxidase. Cell Rep 2020; 29:4114-4126.e5. [PMID: 31851937 PMCID: PMC6946597 DOI: 10.1016/j.celrep.2019.11.054] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/07/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
In eukaryotes, cellular respiration is driven by mitochondrial cytochrome c oxidase (CcO), an enzyme complex that requires copper cofactors for its catalytic activity. Insertion of copper into its catalytically active subunits, including COX2, is a complex process that requires metallochaperones and redox proteins including SCO1, SCO2, and COA6, a recently discovered protein whose molecular function is unknown. To uncover the molecular mechanism by which COA6 and SCO proteins mediate copper delivery to COX2, we have solved the solution structure of COA6, which reveals a coiled-coil-helix-coiled-coil-helix domain typical of redox-active proteins found in the mitochondrial inter-membrane space. Accordingly, we demonstrate that COA6 can reduce the copper-coordinating disulfides of its client proteins, SCO1 and COX2, allowing for copper binding. Finally, our determination of the interaction surfaces and reduction potentials of COA6 and its client proteins provides a mechanism of how metallochaperone and disulfide reductase activities are coordinated to deliver copper to CcO. Soma et al. reports the solution structure of cytochrome c oxidase assembly factor COA6 and establishes that it functions as a thiol-disulfide oxidoreductase in a relay system that delivers copper to COX2, a copper-containing subunit of the mitochondrial cytochrome c oxidase.
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Affiliation(s)
- Shivatheja Soma
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Marcos N Morgada
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Área Biofísica, Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario (2000), Argentina
| | - Mandar T Naik
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Aren Boulet
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Anna A Roesler
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Nathaniel Dziuba
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Alok Ghosh
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Qinhong Yu
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Scot C Leary
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Alejandro J Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Área Biofísica, Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario (2000), Argentina
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA.
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Riedel S, Siemiatkowska B, Watanabe M, Müller CS, Schünemann V, Hoefgen R, Leimkühler S. The ABCB7-Like Transporter PexA in Rhodobacter capsulatus Is Involved in the Translocation of Reactive Sulfur Species. Front Microbiol 2019; 10:406. [PMID: 30918498 PMCID: PMC6424863 DOI: 10.3389/fmicb.2019.00406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/15/2019] [Indexed: 12/23/2022] Open
Abstract
The mitochondrial ATP-binding cassette (ABC) transporters ABCB7 in humans, Atm1 in yeast and ATM3 in plants, are highly conserved in their overall architecture and particularly in their glutathione binding pocket located within the transmembrane spanning domains. These transporters have attracted interest in the last two decades based on their proposed role in connecting the mitochondrial iron-sulfur (Fe-S) cluster assembly with its cytosolic Fe-S cluster assembly (CIA) counterpart. So far, the specific compound that is transported across the membrane remains unknown. In this report we characterized the ABCB7-like transporter Rcc02305 in Rhodobacter capsulatus, which shares 47% amino acid sequence identity with its mitochondrial counterpart. The constructed interposon mutant strain in R. capsulatus displayed increased levels of intracellular reactive oxygen species without a simultaneous accumulation of the cellular iron levels. The inhibition of endogenous glutathione biosynthesis resulted in an increase of total glutathione levels in the mutant strain. Bioinformatic analysis of the amino acid sequence motifs revealed a potential aminotransferase class-V pyridoxal-5'-phosphate (PLP) binding site that overlaps with the Walker A motif within the nucleotide binding domains of the transporter. PLP is a well characterized cofactor of L-cysteine desulfurases like IscS and NFS1 which has a role in the formation of a protein-bound persulfide group within these proteins. We therefore suggest renaming the ABCB7-like transporter Rcc02305 in R. capsulatus to PexA for PLP binding exporter. We further suggest that this ABC-transporter in R. capsulatus is involved in the formation and export of polysulfide species to the periplasm.
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Affiliation(s)
- Simona Riedel
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Potsdam, Germany
| | - Beata Siemiatkowska
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Mutsumi Watanabe
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Christina S Müller
- Biophysics and Medical Physics Group, Department of Physics, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Volker Schünemann
- Biophysics and Medical Physics Group, Department of Physics, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Rainer Hoefgen
- Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, Department of Molecular Enzymology, University of Potsdam, Potsdam, Germany
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6
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Augmenter of liver regeneration: Essential for growth and beyond. Cytokine Growth Factor Rev 2018; 45:65-80. [PMID: 30579845 DOI: 10.1016/j.cytogfr.2018.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/12/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022]
Abstract
Liver regeneration is a well-orchestrated process that is triggered by tissue loss due to trauma or surgical resection and by hepatocellular death induced by toxins or viral infections. Due to the central role of the liver for body homeostasis, intensive research was conducted to identify factors that might contribute to hepatic growth and regeneration. Using a model of partial hepatectomy several factors including cytokines and growth factors that regulate this process were discovered. Among them, a protein was identified to specifically support liver regeneration and therefore was named ALR (Augmenter of Liver Regeneration). ALR protein is encoded by GFER (growth factor erv1-like) gene and can be regulated by various stimuli. ALR is expressed in different tissues in three isoforms which are associated with multiple functions: The long forms of ALR were found in the inner-mitochondrial space (IMS) and the cytosol. Mitochondrial ALR (23 kDa) was shown to cooperate with Mia40 to insure adequate protein folding during import into IMS. On the other hand short form ALR, located mainly in the cytosol, was attributed with anti-apoptotic and anti-oxidative properties as well as its inflammation and metabolism modulating effects. Although a considerable amount of work has been devoted to summarizing the knowledge on ALR, an investigation of ALR expression in different organs (location, subcellular localization) as well as delineation between the isoforms and function of ALR is still missing. This review provides a comprehensive evaluation of ALR structure and expression of different ALR isoforms. Furthermore, we highlight the functional role of endogenously expressed and exogenously applied ALR, as well as an analysis of the clinical importance of ALR, with emphasis on liver disease and in vivo models, as well as the consequences of mutations in the GFER gene.
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Sjuts I, Soll J, Bölter B. Import of Soluble Proteins into Chloroplasts and Potential Regulatory Mechanisms. FRONTIERS IN PLANT SCIENCE 2017; 8:168. [PMID: 28228773 PMCID: PMC5296341 DOI: 10.3389/fpls.2017.00168] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/26/2017] [Indexed: 05/20/2023]
Abstract
Chloroplasts originated from an endosymbiotic event in which a free-living cyanobacterium was engulfed by an ancestral eukaryotic host. During evolution the majority of the chloroplast genetic information was transferred to the host cell nucleus. As a consequence, proteins formerly encoded by the chloroplast genome are now translated in the cytosol and must be subsequently imported into the chloroplast. This process involves three steps: (i) cytosolic sorting procedures, (ii) binding to the designated receptor-equipped target organelle and (iii) the consecutive translocation process. During import, proteins have to overcome the two barriers of the chloroplast envelope, namely the outer envelope membrane (OEM) and the inner envelope membrane (IEM). In the majority of cases, this is facilitated by two distinct multiprotein complexes, located in the OEM and IEM, respectively, designated TOC and TIC. Plants are constantly exposed to fluctuating environmental conditions such as temperature and light and must therefore regulate protein composition within the chloroplast to ensure optimal functioning of elementary processes such as photosynthesis. In this review we will discuss the recent models of each individual import stage with regard to short-term strategies that plants might use to potentially acclimate to changes in their environmental conditions and preserve the chloroplast protein homeostasis.
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Affiliation(s)
- Inga Sjuts
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-UniversitätMunich, Germany
| | - Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-UniversitätMunich, Germany
- *Correspondence: Bettina Bölter,
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Bölter B, Soll J. Once upon a Time - Chloroplast Protein Import Research from Infancy to Future Challenges. MOLECULAR PLANT 2016; 9:798-812. [PMID: 27142186 DOI: 10.1016/j.molp.2016.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 05/08/2023]
Abstract
Protein import into chloroplasts has been a focus of research for several decades. The first publications dealing with this fascinating topic appeared in the 1970s. From the initial realization that many plastid proteins are being encoded for in the nucleus and require transport into their target organelle to the identification of import components in the cytosol, chloroplast envelopes, and stroma, as well as elucidation of some mechanistic details, more fascinating aspects are still being unraveled. With this overview, we present a survey of the beginnings of chloroplast protein import research, the first steps on this winding road, and end with a glimpse into the future.
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Affiliation(s)
- Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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9
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Chatzi A, Manganas P, Tokatlidis K. Oxidative folding in the mitochondrial intermembrane space: A regulated process important for cell physiology and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1298-306. [PMID: 27033519 PMCID: PMC5405047 DOI: 10.1016/j.bbamcr.2016.03.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/05/2023]
Abstract
Mitochondria are fundamental organelles with a complex internal architecture that fulfill important diverse functions including iron–sulfur cluster assembly and cell respiration. Intense work for more than 30 years has identified the key protein import components and the pathways involved in protein targeting and assembly. More recently, oxidative folding has been discovered as one important mechanism for mitochondrial proteostasis whilst several human disorders have been linked to this pathway. We describe the molecular components of this pathway in view of their putative redox regulation and we summarize available evidence on the connections of these pathways to human disorders. Mitochondria are the cell center of iron–sulfur cluster assembly and cell respiration. The MIA pathway has recently been linked to Fe/S pathways, Ca2 + uptake and apoptosis. Mitochondria along with the ER and peroxisomes are major sources of ROS. Many diseases have been linked to mitochondrial dysfunction.
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Affiliation(s)
- Afroditi Chatzi
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Phanee Manganas
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK; Department of Materials Science and Technology, University of Crete, Heraklion, Crete, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece.
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10
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Kang ZH, Wang GX. Redox regulation in the thylakoid lumen. JOURNAL OF PLANT PHYSIOLOGY 2016; 192:28-37. [PMID: 26812087 DOI: 10.1016/j.jplph.2015.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 12/04/2015] [Accepted: 12/04/2015] [Indexed: 06/05/2023]
Abstract
Higher plants need to balance the efficiency of light energy absorption and dissipative photo-protection when exposed to fluctuations in light quantity and quality. This aim is partially realized through redox regulation within the chloroplast, which occurs in all chloroplast compartments except the envelope intermembrane space. In contrast to the chloroplast stroma, less attention has been paid to the thylakoid lumen, an inner, continuous space enclosed by the thylakoid membrane in which redox regulation is also essential for photosystem biogenesis and function. This sub-organelle compartment contains at least 80 lumenal proteins, more than 30 of which are known to contain disulfide bonds. Thioredoxins (Trx) in the chloroplast stroma are photo-reduced in the light, transferring reducing power to the proteins in the thylakoid membrane and ultimately the lumen through a trans-thylakoid membrane-reduced, equivalent pathway. The discovery of lumenal thiol oxidoreductase highlights the importance of the redox regulation network in the lumen for controlling disulfide bond formation, which is responsible for protein activity and folding and even plays a role in photo-protection. In addition, many lumenal members involved in photosystem assembly and non-photochemical quenching are likely required for reduction and/or oxidation to maintain their proper efficiency upon changes in light intensity. In light of recent findings, this review summarizes the multiple redox processes that occur in the thylakoid lumen in great detail, highlighting the essential auxiliary roles of lumenal proteins under fluctuating light conditions.
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Affiliation(s)
- Zhen-Hui Kang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Gui-Xue Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Bioengineering College of Chongqing University, Chongqing 400030, China.
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Szarka A, Bánhegyi G. Oxidative folding: recent developments. Biomol Concepts 2015; 2:379-90. [PMID: 25962043 DOI: 10.1515/bmc.2011.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/21/2011] [Indexed: 01/29/2023] Open
Abstract
Disulfide bond formation in proteins is an effective tool of both structure stabilization and redox regulation. The prokaryotic periplasm and the endoplasmic reticulum of eukaryotes were long considered as the only compartments for enzyme mediated formation of stable disulfide bonds. Recently, the mitochondrial intermembrane space has emerged as the third protein-oxidizing compartment. The classic view on the mechanism of oxidative folding in the endoplasmic reticulum has also been reshaped by new observations. Moreover, besides the structure stabilizing function, reversible disulfide bridge formation in some proteins of the endoplasmic reticulum, seems to play a regulatory role. This review briefly summarizes the present knowledge of the redox systems supporting oxidative folding, emphasizing recent developments.
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Bölter B, Soll J, Schwenkert S. Redox meets protein trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:949-56. [PMID: 25626173 DOI: 10.1016/j.bbabio.2015.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 11/15/2022]
Abstract
After the engulfment of two prokaryotic organisms, the thus emerged eukaryotic cell needed to establish means of communication and signaling to properly integrate the acquired organelles into its metabolism. Regulatory mechanisms had to evolve to ensure that chloroplasts and mitochondria smoothly function in accordance with all other cellular processes. One essential process is the post-translational import of nuclear encoded organellar proteins, which needs to be adapted according to the requirements of the plant. The demand for protein import is constantly changing depending on varying environmental conditions, as well as external and internal stimuli or different developmental stages. Apart from long-term regulatory mechanisms such as transcriptional/translation control, possibilities for short-term acclimation are mandatory. To this end, protein import is integrated into the cellular redox network, utilizing the recognition of signals from within the organelles and modifying the efficiency of the translocon complexes. Thereby, cellular requirements can be communicated throughout the whole organism. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany.
| | - Serena Schwenkert
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
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13
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Hofbauer A, Peters J, Arcalis E, Rademacher T, Lampel J, Eudes F, Vitale A, Stoger E. The Induction of Recombinant Protein Bodies in Different Subcellular Compartments Reveals a Cryptic Plastid-Targeting Signal in the 27-kDa γ-Zein Sequence. Front Bioeng Biotechnol 2014; 2:67. [PMID: 25566533 PMCID: PMC4263181 DOI: 10.3389/fbioe.2014.00067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/24/2014] [Indexed: 11/18/2022] Open
Abstract
Naturally occurring storage proteins such as zeins are used as fusion partners for recombinant proteins because they induce the formation of ectopic storage organelles known as protein bodies (PBs) where the proteins are stabilized by intermolecular interactions and the formation of disulfide bonds. Endogenous PBs are derived from the endoplasmic reticulum (ER). Here, we have used different targeting sequences to determine whether ectopic PBs composed of the N-terminal portion of mature 27 kDa γ-zein added to a fluorescent protein could be induced to form elsewhere in the cell. The addition of a transit peptide for targeting to plastids causes PB formation in the stroma, whereas in the absence of any added targeting sequence PBs were typically associated with the plastid envelope, revealing the presence of a cryptic plastid-targeting signal within the γ-zein cysteine-rich domain. The subcellular localization of the PBs influences their morphology and the solubility of the stored recombinant fusion protein. Our results indicate that the biogenesis and budding of PBs does not require ER-specific factors and therefore, confirm that γ-zein is a versatile fusion partner for recombinant proteins offering unique opportunities for the accumulation and bioencapsulation of recombinant proteins in different subcellular compartments.
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Affiliation(s)
- Anna Hofbauer
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences , Vienna , Austria
| | - Jenny Peters
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences , Vienna , Austria
| | - Elsa Arcalis
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences , Vienna , Austria
| | - Thomas Rademacher
- Institute of Molecular Biotechnology, RWTH Aachen University , Aachen , Germany
| | - Johannes Lampel
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences , Vienna , Austria
| | - François Eudes
- Agriculture and Agri-Food Canada , Lethbridge, AB , Canada
| | - Alessandro Vitale
- Institute of Agricultural Biology and Biotechnology, National Research Council (CNR) , Milan , Italy
| | - Eva Stoger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences , Vienna , Austria
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14
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Abicht HK, Schärer MA, Quade N, Ledermann R, Mohorko E, Capitani G, Hennecke H, Glockshuber R. How periplasmic thioredoxin TlpA reduces bacterial copper chaperone ScoI and cytochrome oxidase subunit II (CoxB) prior to metallation. J Biol Chem 2014; 289:32431-44. [PMID: 25274631 DOI: 10.1074/jbc.m114.607127] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two critical cysteine residues in the copper-A site (Cu(A)) on subunit II (CoxB) of bacterial cytochrome c oxidase lie on the periplasmic side of the cytoplasmic membrane. As the periplasm is an oxidizing environment as compared with the reducing cytoplasm, the prediction was that a disulfide bond formed between these cysteines must be eliminated by reduction prior to copper insertion. We show here that a periplasmic thioredoxin (TlpA) acts as a specific reductant not only for the Cu(2+) transfer chaperone ScoI but also for CoxB. The dual role of TlpA was documented best with high-resolution crystal structures of the kinetically trapped TlpA-ScoI and TlpA-CoxB mixed disulfide intermediates. They uncovered surprisingly disparate contact sites on TlpA for each of the two protein substrates. The equilibrium of CoxB reduction by TlpA revealed a thermodynamically favorable reaction, with a less negative redox potential of CoxB (E'0 = -231 mV) as compared with that of TlpA (E'0 = -256 mV). The reduction of CoxB by TlpA via disulfide exchange proved to be very fast, with a rate constant of 8.4 × 10(4) M(-1) s(-1) that is similar to that found previously for ScoI reduction. Hence, TlpA is a physiologically relevant reductase for both ScoI and CoxB. Although the requirement of ScoI for assembly of the Cu(A)-CoxB complex may be bypassed in vivo by high environmental Cu(2+) concentrations, TlpA is essential in this process because only reduced CoxB can bind copper ions.
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Affiliation(s)
- Helge K Abicht
- From the Institute of Molecular Biology and Biophysics and Institute of Microbiology, ETH Zürich, CH-8093 Zürich and
| | - Martin A Schärer
- From the Institute of Molecular Biology and Biophysics and the Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Nick Quade
- From the Institute of Molecular Biology and Biophysics and
| | | | | | - Guido Capitani
- the Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Hauke Hennecke
- Institute of Microbiology, ETH Zürich, CH-8093 Zürich and
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15
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Koch JR, Schmid FX. Mia40 is optimized for function in mitochondrial oxidative protein folding and import. ACS Chem Biol 2014; 9:2049-57. [PMID: 24983157 DOI: 10.1021/cb500408n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mia40 catalyzes oxidative protein folding in mitochondria. It contains a unique catalytic CPC dithiol flanked by a hydrophobic groove, and unlike other oxidoreductases, it forms long-lived mixed disulfides with substrates. We show that this distinctive property originates neither from particular properties of mitochondrial substrates nor from the CPC motif of Mia40. The catalytic cysteines of Mia40 display unusually low chemical reactivity, as expressed in conventional pK values and reduction potentials. The stability of the mixed disulfide intermediate is coupled energetically with hydrophobic interactions between Mia40 and the substrate. Based on these properties, we suggest a mechanism for Mia40, where the hydrophobic binding site is employed to select a substrate thiol for forming the initial mixed disulfide. Its long lifetime is used to retain partially folded proteins in the mitochondria and to direct folding toward forming the native disulfide bonds.
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Affiliation(s)
- Johanna R. Koch
- Laboratorium
für Biochemie
und Bayreuther Zentrum für Molekulare Biologie, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Franz X. Schmid
- Laboratorium
für Biochemie
und Bayreuther Zentrum für Molekulare Biologie, Universität Bayreuth, 95440 Bayreuth, Germany
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16
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Mia40 targets cysteines in a hydrophobic environment to direct oxidative protein folding in the mitochondria. Nat Commun 2014; 5:3041. [DOI: 10.1038/ncomms4041] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 11/29/2013] [Indexed: 11/08/2022] Open
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17
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The baculovirus sulfhydryl oxidase Ac92 (P33) interacts with the Spodoptera frugiperda P53 protein and oxidizes it in vitro. Virology 2013; 447:197-207. [PMID: 24210115 DOI: 10.1016/j.virol.2013.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/03/2013] [Accepted: 09/06/2013] [Indexed: 11/23/2022]
Abstract
The Autographa californica M nucleopolyhedrovirus (AcMNPV) sulfhydryl oxidase Ac92 is essential for production of infectious virions. Ac92 also interacts with human p53 and enhances human p53-induced apoptosis in insect cells, but it is not known whether any relationship exists between Ac92 and native p53 homologs from insect hosts of AcMNPV. We found that Ac92 interacted with SfP53 from Spodoptera frugiperda in infected cells and oxidized SfP53 in vitro. However, Ac92 did not interact with or oxidize a mutant of SfP53 predicted to lack DNA binding. Silencing Sfp53 expression did not rescue the ability of an ac92-knockout virus to produce infectious virus. Similarly, ac92 expression did not affect SfP53-stimulated caspase activity or the localization of SfP53. Thus, although Ac92 binds to SfP53 during AcMNPV replication and oxidizes SfP53 in vitro, we could not detect any effects of this interaction on AcMNPV replication in cultured cells.
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18
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Lu Y, Wang HR, Li H, Cui HR, Feng YG, Wang XY. A chloroplast membrane protein LTO1/AtVKOR involving in redox regulation and ROS homeostasis. PLANT CELL REPORTS 2013; 32:1427-40. [PMID: 23689258 DOI: 10.1007/s00299-013-1455-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/20/2013] [Accepted: 04/29/2013] [Indexed: 05/08/2023]
Abstract
The role of LTO1/ At VKOR-DsbA in ROS homeostasis and in redox regulation of cysteine-containing proteins in chloroplast was studied in lto1 - 2 mutant, and a potential target of LTO1 was captured. A chloroplast membrane protein LTO1/AtVKOR-DsbA encoded by the gene At4g35760 was recently found to be an oxidoreductase and involved in assembly of PSII. Here, the growth of a mutant lto1-2 line of Arabidopsis was found to be severely stunted and transgenic complementation ultimately demonstrated the phenotype changes were due to this gene. A proteomic experiment identified 23 proteins presenting a differential abundance in lto1-2 compared with wild-type plants, including components in PSII and proteins scavenging active oxygen. Three scavengers of active oxygen, L-ascorbate peroxidase 1, peroxisomal catalase 2, dehydroascorbate reductase 1, are reduced in lto1-2 plants, corresponding to high levels of accumulation of reactive oxygen species (ROS). The photosynthetic activities of PSII and the quantity of core protein D1 decreased significantly in lto1-2. Further investigation showed the synthesis of D1 was not affected in mutants both at transcription and translation levels. The soluble DsbA-like domain of LTO1 was found to have reduction, oxidation and isomerization activities, and could promote the formation of disulfide bonds in a lumenal protein, FKBP13. A potential target of LTO1 was captured which was involving in chlorophyll degradation and photooxidative stress response. Experimental results imply that LTO1 plays important roles in redox regulation, ROS homeostasis and maintenance of PSII.
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Affiliation(s)
- Ying Lu
- College of Life Science, Shandong Agricultural University, Taian 271018, Shandong, People's Republic of China
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19
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Abstract
SIGNIFICANCE Disulfide-bonded proteins in chloroplasts from green plants exist in the envelope and the thylakoid membrane, and in the stroma and the lumen. The formation of disulfide bonds in proteins is referred to as oxidative folding and is linked to the import and folding of chloroplast proteins as well as the assembly and repair of thylakoid complexes. It is also important in the redox regulation of enzymes and signal transfer. RECENT ADVANCES Green-plant chloroplasts contain enzymes that can form and isomerize disulfide bonds in proteins. In Arabidopsis thaliana, four proteins are identified that are relevant for the catalysis of disulfide bond formation in chloroplast proteins. The proteins' low quantum yield of Photosystem II 1 (LQY1, At1g75690) and snowy cotyledon 2 (SCO2, At3g19220) exhibits protein disulfide isomerase activity and is suggested to function in the assembly and repair of Photosystem II (PSII), and the biogenesis of thylakoids in cotyledons, respectively. The thylakoid-located Lumen thiol oxidoreductase 1 (LTO1, At4g35760) can catalyze the formation of the disulfide bond of the extrinsic PsbO protein of PSII. In addition, the stroma-located protein disulfide isomerase PDIL1-3 (At3g54960) may have a role in oxidative folding. CRITICAL ISSUES Research on oxidative folding in chloroplasts plants is in an early stage and little is known about the mechanisms of disulfide bond formation in chloroplast proteins. FUTURE DIRECTIONS The close link between the import and folding of chloroplast proteins suggests that Hsp93, a component of the inner envelope's import apparatus, may have co-chaperones that can catalyze disulfide bond formation in newly imported proteins.
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20
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De Marchis F, Pompa A, Bellucci M. Plastid proteostasis and heterologous protein accumulation in transplastomic plants. PLANT PHYSIOLOGY 2012; 160:571-81. [PMID: 22872774 PMCID: PMC3461539 DOI: 10.1104/pp.112.203778] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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21
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Bourens M, Dabir DV, Tienson HL, Sorokina I, Koehler CM, Barrientos A. Role of twin Cys-Xaa9-Cys motif cysteines in mitochondrial import of the cytochrome C oxidase biogenesis factor Cmc1. J Biol Chem 2012; 287:31258-69. [PMID: 22767599 PMCID: PMC3438957 DOI: 10.1074/jbc.m112.383562] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/02/2012] [Indexed: 11/06/2022] Open
Abstract
The Mia40 import pathway facilitates the import and oxidative folding of cysteine-rich protein substrates into the mitochondrial intermembrane space. Here we describe the in vitro and in organello oxidative folding of Cmc1, a twin CX(9)C-containing substrate, which contains an unpaired cysteine. In vitro, Cmc1 can be oxidized by the import receptor Mia40 alone when in excess or at a lower rate by only the sulfhydryl oxidase Erv1. However, physiological and efficient Cmc1 oxidation requires Erv1 and Mia40. Cmc1 forms a stable intermediate with Mia40 and is released from this interaction in the presence of Erv1. The three proteins are shown to form a ternary complex in mitochondria. Our results suggest that this mechanism facilitates efficient formation of multiple disulfides and prevents the formation of non-native disulfide bonds.
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Affiliation(s)
- Myriam Bourens
- Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Deepa V. Dabir
- the Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, and
| | - Heather L. Tienson
- the Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, and
| | | | - Carla M. Koehler
- the Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, and
| | - Antoni Barrientos
- From the Departments of Biochemistry & Molecular Biology and
- Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
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22
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Cytosolic thioredoxin system facilitates the import of mitochondrial small Tim proteins. EMBO Rep 2012; 13:916-22. [PMID: 22878414 DOI: 10.1038/embor.2012.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 07/05/2012] [Accepted: 07/13/2012] [Indexed: 11/08/2022] Open
Abstract
Thiol-disulphide redox regulation has a key role during the biogenesis of mitochondrial intermembrane space (IMS) proteins. Only the Cys-reduced form of precursor proteins can be imported into mitochondria, which is followed by disulphide bond formation in the mitochondrial IMS. In contrast to the wealth of knowledge on the oxidation process inside mitochondria, little is known about how precursors are maintained in an import-competent form in the cytosol. Here we provide the first evidence that the cytosolic thioredoxin system is required to maintain the IMS small Tim proteins in reduced forms and facilitate their mitochondrial import during respiratory growth.
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23
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Huynen MA, Duarte I, Szklarczyk R. Loss, replacement and gain of proteins at the origin of the mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:224-31. [PMID: 22902511 DOI: 10.1016/j.bbabio.2012.08.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/19/2012] [Accepted: 08/05/2012] [Indexed: 01/28/2023]
Abstract
We review what has been inferred about the changes at the level of the proteome that accompanied the evolution of the mitochondrion from an alphaproteobacterium. We regard these changes from an alphaproteobacterial perspective: which proteins were lost during mitochondrial evolution? And, of the proteins that were lost, which ones have been replaced by other, non-orthologous proteins with a similar function? Combining literature-supported replacements with quantitative analyses of mitochondrial proteomics data we infer that most of the loss and replacements that separate current day mitochondria in mammals from alphaproteobacteria took place before the radiation of the eukaryotes. Recent analyses show that also the acquisition of new proteins to the large protein complexes of the oxidative phosphorylation and the mitochondrial ribosome occurred mainly before the divergence of the eukaryotes. These results indicate a significant number of pivotal evolutionary events between the acquisition of the endosymbiont and the radiation of the eukaryotes and therewith support an early acquisition of mitochondria in eukaryotic evolution. Technically, advancements in the reconstruction of the evolutionary trajectories of loss, replacement and gain of mitochondrial proteins depend on using profile-based homology detection methods for sequence analysis. We highlight the mitochondrial Holliday junction resolvase endonuclease, for which such methods have detected new "family members" and in which function differentiation is accompanied by the loss of catalytic residues for the original enzymatic function and the gain of a protein domain for the new function. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
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Affiliation(s)
- Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6400 HB Nijmegen, The Netherlands.
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24
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Karamoko M, Cline S, Redding K, Ruiz N, Hamel PP. Lumen Thiol Oxidoreductase1, a disulfide bond-forming catalyst, is required for the assembly of photosystem II in Arabidopsis. THE PLANT CELL 2011; 23:4462-75. [PMID: 22209765 PMCID: PMC3269877 DOI: 10.1105/tpc.111.089680] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/15/2011] [Accepted: 12/13/2011] [Indexed: 05/18/2023]
Abstract
Here, we identify Arabidopsis thaliana Lumen Thiol Oxidoreductase1 (LTO1) as a disulfide bond-forming enzyme in the thylakoid lumen. Using topological reporters in bacteria, we deduced a lumenal location for the redox active domains of the protein. LTO1 can partially substitute for the proteins catalyzing disulfide bond formation in the bacterial periplasm, which is topologically equivalent to the plastid lumen. An insertional mutation within the LTO1 promoter is associated with a severe photoautotrophic growth defect. Measurements of the photosynthetic activity indicate that the lto1 mutant displays a limitation in the electron flow from photosystem II (PSII). In accordance with these measurements, we noted a severe depletion of the structural subunits of PSII but no change in the accumulation of the cytochrome b(6)f complex or photosystem I. In a yeast two-hybrid assay, the thioredoxin-like domain of LTO1 interacts with PsbO, a lumenal PSII subunit known to be disulfide bonded, and a recombinant form of the molecule can introduce a disulfide bond in PsbO in vitro. The documentation of a sulfhydryl-oxidizing activity in the thylakoid lumen further underscores the importance of catalyzed thiol-disulfide chemistry for the biogenesis of the thylakoid compartment.
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Affiliation(s)
- Mohamed Karamoko
- Department of Molecular Genetics and Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Sara Cline
- Department of Molecular Genetics and Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, Columbus, Ohio 43210
| | - Kevin Redding
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287
| | - Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - Patrice P. Hamel
- Department of Molecular Genetics and Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, Columbus, Ohio 43210
- Address correspondence to
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25
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de Vitry C. Cytochrome c maturation system on the negative side of bioenergetic membranes: CCB or System IV. FEBS J 2011; 278:4189-97. [DOI: 10.1111/j.1742-4658.2011.08373.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Ghorbani-Choghamarani A, Soleiman-Beigi M, Noormohammadi F. Trimethylphenylammonium Tribromide as a New and Efficient Oxidizing Agent for the Oxidative Coupling of Thiols into Disulfides and Chemoselective Oxidation of Sulfides into Sulfoxides. PHOSPHORUS SULFUR 2011. [DOI: 10.1080/10426507.2010.527878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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De Marchis F, Pompa A, Mannucci R, Morosinotto T, Bellucci M. A plant secretory signal peptide targets plastome-encoded recombinant proteins to the thylakoid membrane. PLANT MOLECULAR BIOLOGY 2011; 76:427-41. [PMID: 20714919 DOI: 10.1007/s11103-010-9676-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Accepted: 07/21/2010] [Indexed: 05/29/2023]
Abstract
Plastids are considered promising bioreactors for the production of recombinant proteins, but the knowledge of the mechanisms regulating foreign protein folding, targeting, and accumulation in these organelles is still incomplete. Here we demonstrate that a plant secretory signal peptide is able to target a plastome-encoded recombinant protein to the thylakoid membrane. The fusion protein zeolin with its native signal peptide expressed by tobacco (Nicotiana tabacum) transplastomic plants was directed into the chloroplast thylakoid membranes, whereas the zeolin mutant devoid of the signal peptide, Δzeolin, is instead accumulated in the stroma. We also show that zeolin folds in the thylakoid membrane where it accumulates as trimers able to form disulphide bonds. Disulphide bonds contribute to protein accumulation since zeolin shows a higher accumulation level with respect to stromal Δzeolin, whose folding is hampered as the protein accumulates at low amounts in a monomeric form and it is not oxidized. Thus, post-transcriptional processes seem to regulate the stability and accumulation of plastid-synthesized zeolin. The most plausible zeolin targeting mechanism to thylakoid is discussed herein.
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Affiliation(s)
- Francesca De Marchis
- Istituto di Genetica Vegetale, Consiglio Nazionale delle Ricerche (CNR), via della Madonna Alta 130, 06128 Perugia, Italy
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28
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Delage L, Leblanc C, Nyvall Collén P, Gschloessl B, Oudot MP, Sterck L, Poulain J, Aury JM, Cock JM. In silico survey of the mitochondrial protein uptake and maturation systems in the brown alga Ectocarpus siliculosus. PLoS One 2011; 6:e19540. [PMID: 21611166 PMCID: PMC3097184 DOI: 10.1371/journal.pone.0019540] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 03/31/2011] [Indexed: 01/24/2023] Open
Abstract
The acquisition of mitochondria was a key event in eukaryote evolution. The aim of this study was to identify homologues of the components of the mitochondrial protein import machinery in the brown alga Ectocarpus and to use this information to investigate the evolutionary history of this fundamental cellular process. Detailed searches were carried out both for components of the protein import system and for related peptidases. Comparative and phylogenetic analyses were used to investigate the evolution of mitochondrial proteins during eukaryote diversification. Key observations include phylogenetic evidence for very ancient origins for many protein import components (Tim21, Tim50, for example) and indications of differences between the outer membrane receptors that recognize the mitochondrial targeting signals, suggesting replacement, rearrangement and/or emergence of new components across the major eukaryotic lineages. Overall, the mitochondrial protein import components analysed in this study confirmed a high level of conservation during evolution, indicating that most are derived from very ancient, ancestral proteins. Several of the protein import components identified in Ectocarpus, such as Tim21, Tim50 and metaxin, have also been found in other stramenopiles and this study suggests an early origin during the evolution of the eukaryotes.
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Affiliation(s)
- Ludovic Delage
- Université Pierre et Marie Curie, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, Roscoff, France
| | - Catherine Leblanc
- Université Pierre et Marie Curie, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, Roscoff, France
| | - Pi Nyvall Collén
- Université Pierre et Marie Curie, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, Roscoff, France
| | - Bernhard Gschloessl
- Université Pierre et Marie Curie, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, Roscoff, France
| | - Marie-Pierre Oudot
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lieven Sterck
- VIB Department of Plant Systems Biology, Ghent University, Ghent, Belgium
| | - Julie Poulain
- Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Génomique, Génoscope, Evry, France
- Centre National de la Recherche Scientifique, UMR 8030, Evry, France
- Université d'Evry, Evry, France
| | - Jean-Marc Aury
- Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Génomique, Génoscope, Evry, France
- Centre National de la Recherche Scientifique, UMR 8030, Evry, France
- Université d'Evry, Evry, France
| | - J. Mark Cock
- Université Pierre et Marie Curie, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, Roscoff, France
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29
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Oxidation-driven protein import into mitochondria: Insights and blind spots. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:981-9. [DOI: 10.1016/j.bbamem.2010.06.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 05/31/2010] [Accepted: 06/02/2010] [Indexed: 11/21/2022]
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30
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Zheng W, Chu Y, Yin Q, Xu L, Yang C, Zhang W, Tang Y, Yang Y. Crucial effect of the first CXXC motif of human QSOX 1b on the activity to different substrates. J Biochem 2010; 149:293-300. [PMID: 21148546 DOI: 10.1093/jb/mvq143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Among all sulphhydryl oxidases involved in disulphide formation, quiescin-sulphhydryl oxidase (QSOX) is unique for its multidomain structure, protein thiol oxidation activity and highly efficient catalysis. In this study, site-directed mutagenesis and molecular modelling methods were integrated to investigate the structural and functional characteristics of QSOX, especially the importance of the three CXXC motifs. Site-directed mutagenesis suggested that the C449-C452 motif was essential for the activity of human QSOX 1b; the C70-C73 motif was fundamental in electron transfer from thiol-containing substrate including reduced proteins, DTT, GSH rather than the phosphine-based thiol reductant TCEP, to the C449-C452 motif; and the C509-C512 motif was not involved in electron transfer during disulphide formation. The different roles of the CXXC motifs indicated that there were discrepant electron transfer pathways for the oxidation of thiol-containing substrates and non-thiol disulphide reductants. Molecular modelling method was then used to draw a reasonable picture for the electron transfer process and to elucidate the mechanism of electron transfer when different substrates were oxidized, which will greatly enhance our understanding of the action mechanism of QSOX.
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Affiliation(s)
- Wenyun Zheng
- State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai, China
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Endo T, Yamano K, Kawano S. Structural basis for the disulfide relay system in the mitochondrial intermembrane space. Antioxid Redox Signal 2010; 13:1359-73. [PMID: 20136511 DOI: 10.1089/ars.2010.3099] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Mitochondria contain two biological membranes. Although reducing agents can diffuse from the cytosol into the intermembrane space (IMS) between the outer and inner mitochondrial membranes, the IMS has a dedicated disulfide relay system to introduce disulfide bonds into mainly small and soluble proteins. This system consists of two essential proteins, a disulfide carrier Tim40/Mia40 and a flavin-dependent sulfhydryl oxidase Erv1, high-resolution structures that have recently become available. Tim40/Mia40 transfers disulfide bonds to newly imported IMS proteins by dithiol/disulfide exchange reactions involving mixed disulfide intermediates. Tight folding by introduction of disulfide bonds prevents egress of these small IMS proteins, resulting in their selective retention in the compartment. After disulfide transfer from Tim40/Mia40 to substrate proteins, Tim40/Mia40 is reoxidized again by Erv1, which is then oxidized by electron transfer to either cytochrome c or molecular oxygen. Here we review the recent advancement of the knowledge on the mechanism of the disulfide relay system in the mitochondrial IMS, especially shedding light on the structural aspects of its components.
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Affiliation(s)
- Toshiya Endo
- Department of Chemistry, Nagoya University, Japan.
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Motohashi K, Hisabori T. CcdA is a thylakoid membrane protein required for the transfer of reducing equivalents from stroma to thylakoid lumen in the higher plant chloroplast. Antioxid Redox Signal 2010; 13:1169-76. [PMID: 20214498 DOI: 10.1089/ars.2010.3138] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In order to transfer reducing equivalents into the thylakoid lumen, a specific thylakoid membrane transfer system is suggested that mediates the disulfide bond reduction of proteins in the thylakoid lumen of higher plant chloroplasts. In this system, although stromal thioredoxin can supply the reducing equivalents to a thioredoxin-like protein HCF164 in the thylakoid lumen, a mediator protein for electron transfer in the thylakoid membranes is proposed to be required to link the two suborganellar compartments. CcdA is a candidate protein as a component for this transfer system since CcdA- and HCF164-deficient mutants in Arabidopsis thaliana show the same phenotype. We now show that CcdA is localized in the thylakoid membrane and that its redox state, as well as that of HCF164, is modulated in thylakoids by stromal m-type thioredoxin. Our results strongly suggest that CcdA may act as a mediator in thylakoid membranes by transferring reducing equivalents from the stromal to the lumenal side of the thylakoid membrane in chloroplasts.
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Affiliation(s)
- Ken Motohashi
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kyoto, Japan.
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33
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Bohnsack MT, Schleiff E. The evolution of protein targeting and translocation systems. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1115-30. [DOI: 10.1016/j.bbamcr.2010.06.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/26/2010] [Accepted: 06/11/2010] [Indexed: 11/28/2022]
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Carrie C, Giraud E, Duncan O, Xu L, Wang Y, Huang S, Clifton R, Murcha M, Filipovska A, Rackham O, Vrielink A, Whelan J. Conserved and novel functions for Arabidopsis thaliana MIA40 in assembly of proteins in mitochondria and peroxisomes. J Biol Chem 2010; 285:36138-48. [PMID: 20829360 DOI: 10.1074/jbc.m110.121202] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The disulfide relay system of the mitochondrial intermembrane space has been extensively characterized in Saccharomyces cerevisiae. It contains two essential components, Mia40 and Erv1. The genome of Arabidopsis thaliana contains a single gene for each of these components. Although insertional inactivation of Erv1 leads to a lethal phenotype, inactivation of Mia40 results in no detectable deleterious phenotype. A. thaliana Mia40 is targeted to and accumulates in mitochondria and peroxisomes. Inactivation of Mia40 results in an alteration of several proteins in mitochondria, an absence of copper/zinc superoxide dismutase (CSD1), the chaperone for superoxide dismutase (Ccs1) that inserts copper into CSD1, and a decrease in capacity and amount of complex I. In peroxisomes the absence of Mia40 leads to an absence of CSD3 and a decrease in abnormal inflorescence meristem 1 (Aim1), a β-oxidation pathway enzyme. Inactivation of Mia40 leads to an alteration of the transcriptome of A. thaliana, with genes encoding peroxisomal proteins, redox functions, and biotic stress significantly changing in abundance. Thus, the mechanistic operation of the mitochondrial disulfide relay system is different in A. thaliana compared with other systems, and Mia40 has taken on new roles in peroxisomes and mitochondria.
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Affiliation(s)
- Chris Carrie
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
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35
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Minor modifications and major adaptations: the evolution of molecular machines driving mitochondrial protein import. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:947-54. [PMID: 20659421 DOI: 10.1016/j.bbamem.2010.07.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Revised: 07/17/2010] [Accepted: 07/20/2010] [Indexed: 11/23/2022]
Abstract
Bacterial endosymbionts gave rise to mitochondria in a process that depended on the acquisition of protein import pathways. Modification and in some cases major re-tooling of the endosymbiont's cellular machinery produced these pathways, establishing mitochondria as organelles common to all eukaryotic cells. The legacy of this evolutionary tinkering can be seen in the homologies and structural similarities between mitochondrial protein import machinery and modern day bacterial proteins. Comparative analysis of these systems is revealing both possible routes for the evolution of the mitochondrial membrane translocases and a greater understanding of the mechanisms behind mitochondrial protein import. This article is part of a Special Issue entitled Protein translocation across or insertion into membranes.
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36
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Stengel A, Benz JP, Soll J, Bölter B. Redox-regulation of protein import into chloroplasts and mitochondria: similarities and differences. PLANT SIGNALING & BEHAVIOR 2010; 5:105-9. [PMID: 20009579 PMCID: PMC2884109 DOI: 10.4161/psb.5.2.10525] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Redox signals play important roles in many developmental and metabolic processes, in particular in chloroplasts and mitochondria. Furthermore, redox reactions are crucial for protein folding via the formation of inter- or intramolecular disulfide bridges. Recently, redox signals were described to be additionally involved in regulation of protein import: in mitochondria, a disulfide relay system mediates retention of cystein-rich proteins in the intermembrane space by oxidizing them. Two essential proteins, the redox-activated receptor Mia40 and the sulfhydryl oxidase Erv1 participate in this pathway. In chloroplasts, it becomes apparent that protein import is affected by redox signals on both the outer and inner envelope: at the level of the Toc complex (translocon at the outer envelope of chloroplasts), the formation/reduction of disulfide bridges between the Toc components has a strong influence on import yield. Moreover, the stromal metabolic redox state seems to be sensed by the Tic complex (translocon at the inner envelope of chloroplasts) that is able to adjust translocation efficiency of a subgroup of redox-related preproteins accordingly. This review summarizes the current knowledge of these redox-regulatory pathways and focuses on similarities and differences between chloroplasts and mitochondria.
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Affiliation(s)
- Anna Stengel
- Munich Center for Integrated Protein Science CiPS(M-), Ludwig-Maximilians-Universität München, Munich, Germany
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37
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Systematic Analysis of the Twin Cx9C Protein Family. J Mol Biol 2009; 393:356-68. [DOI: 10.1016/j.jmb.2009.08.041] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/14/2009] [Accepted: 08/17/2009] [Indexed: 11/20/2022]
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38
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Kessler F, Schnell D. Chloroplast biogenesis: diversity and regulation of the protein import apparatus. Curr Opin Cell Biol 2009; 21:494-500. [DOI: 10.1016/j.ceb.2009.03.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 03/24/2009] [Accepted: 03/26/2009] [Indexed: 01/14/2023]
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39
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Saint-Marcoux D, Wollman FA, de Vitry C. Biogenesis of cytochrome b6 in photosynthetic membranes. ACTA ACUST UNITED AC 2009; 185:1195-207. [PMID: 19564403 PMCID: PMC2712960 DOI: 10.1083/jcb.200812025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In chloroplasts, binding of a c′-heme to cytochrome b6 on the stromal side of the thylakoid membranes requires a specific mechanism distinct from the one at work for c-heme binding to cytochromes f and c6 on the lumenal side of membranes. Here, we show that the major protein components of this pathway, the CCBs, are bona fide transmembrane proteins. We demonstrate their association in a series of hetero-oligomeric complexes, some of which interact transiently with cytochrome b6 in the process of heme delivery to the apoprotein. In addition, we provide preliminary evidence for functional assembly of cytochrome b6f complexes even in the absence of c′-heme binding to cytochrome b6. Finally, we present a sequential model for apo- to holo-cytochrome b6 maturation integrated within the assembly pathway of b6f complexes in the thylakoid membranes.
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Affiliation(s)
- Denis Saint-Marcoux
- Centre National de la Recherche Scientifique, UMR 7141, Physiologie Membranaire et Moléculaire du Chloroplaste, Institut de Biologie Physico-Chimique, 75005 Paris, France
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40
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Kutik S, Stroud DA, Wiedemann N, Pfanner N. Evolution of mitochondrial protein biogenesis. Biochim Biophys Acta Gen Subj 2009; 1790:409-15. [DOI: 10.1016/j.bbagen.2009.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 04/02/2009] [Accepted: 04/06/2009] [Indexed: 02/08/2023]
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41
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The coiled coil-helix-coiled coil-helix proteins may be redox proteins. FEBS Lett 2009; 583:1699-702. [PMID: 19345215 DOI: 10.1016/j.febslet.2009.03.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 03/27/2009] [Indexed: 01/05/2023]
Abstract
A number of nuclear encoded proteins are imported in to the intermembrane space of mitochondria where they adopt a coiled coil-helix-coiled coil-helix (CHCH) fold. Two disulfide bonds formed by twin CX(3)C or CX(9)C motifs stabilize this fold. Some of these proteins are also characterized at their N-termini by the presence of two additional cysteine residues which can perform oxidoreductase or metallochaperone functions or both. This fold represents the most 'minimal' oxidoreductase domain described so far.
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42
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Jezek P, Plecitá-Hlavatá L. Mitochondrial reticulum network dynamics in relation to oxidative stress, redox regulation, and hypoxia. Int J Biochem Cell Biol 2009; 41:1790-804. [PMID: 19703650 DOI: 10.1016/j.biocel.2009.02.014] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 02/03/2023]
Abstract
A single mitochondrial network in the cell undergoes constant fission and fusion primarily depending on the local GTP gradients and the mitochondrial energetics. Here we overview the main properties and regulation of pro-fusion and pro-fission mitodynamins, i.e. dynamins-related GTPases responsible for mitochondrial shape-forming, such as pro-fusion mitofusins MFN1, MFN2, and the inner membrane-residing long OPA1 isoforms, and pro-fission mitodynamins FIS1, MFF, and DRP1 multimers required for scission. Notably, the OPA1 cleavage into non-functional short isoforms at a diminished ATP level (collapsed membrane potential) and the DRP1 recruitment upon phosphorylation by various kinases are overviewed. Possible responses of mitodynamins to the oxidative stress, hypoxia, and concomitant mtDNA mutations are also discussed. We hypothesize that the increased GTP formation within the Krebs cycle followed by the GTP export via the ADP/ATP carrier shift the balance between fission and fusion towards fusion by activating the GTPase domain of OPA1 located in the peripheral intermembrane space (PIMS). Since the protein milieu of PIMS is kept at the prevailing oxidized redox potential by the TOM, MIA40 and ALR/Erv1 import-redox trapping system, redox regulations shift the protein environment of PIMS to a more reduced state due to the higher substrate load and increased respiration. A higher cytochrome c turnover rate may prevent electron transfer from ALR/Erv1 to cytochrome c. Nevertheless, the putative links between the mitodynamin responses, mitochondrial morphology and the changes in the mitochondrial bioenergetics, superoxide production, and hypoxia are yet to be elucidated, including the precise basis for signaling by the mitochondrion-derived vesicles.
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Affiliation(s)
- Petr Jezek
- Department of Membrane Transport Biophysics, No. 75, Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Vídenská 1083, CZ 14220 Prague, Czech Republic.
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