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Liu L, Li X, Su M, Shi J, Zhang Q, Liu X. LeGRXS14 Reduces Salt Stress Tolerance in Arabidopsis thaliana. PLANTS (BASEL, SWITZERLAND) 2023; 12:2320. [PMID: 37375946 PMCID: PMC10305512 DOI: 10.3390/plants12122320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/01/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023]
Abstract
Salt stress represents a significant abiotic stressor for plants and poses a severe threat to agricultural productivity. Glutaredoxins (GRXs) are small disulfide reductases that can scavenge cellular reactive oxygen species and are crucial for plant growth and development, particularly under stressful circumstances. Although CGFS-type GRXs were found to be involved in various abiotic stresses, the intrinsic mechanism mediated by LeGRXS14, a tomato (Lycopersicon esculentum Mill.) CGFS-type GRX, is not yet fully understood. We discovered that LeGRXS14 is relatively conserved at the N-terminus and exhibits an increase in expression level under salt and osmotic stress conditions in tomatoes. The expression levels of LeGRXS14 in response to osmotic stress peaked relatively rapidly at 30 min, while the response to salt stress only peaked at 6 h. We constructed LeGRXS14 overexpression Arabidopsis thaliana (OE) lines and confirmed that LeGRXS14 is located on the plasma membrane, nucleus, and chloroplasts. In comparison to the wild-type Col-0 (WT), the OE lines displayed greater sensitivity to salt stress, resulting in a profound inhibition of root growth under the same conditions. Analysis of the mRNA levels of the WT and OE lines revealed that salt stress-related factors, such as ZAT12, SOS3, and NHX6, were downregulated. Based on our research, it can be concluded that LeGRXS14 plays a significant role in plant tolerance to salt. However, our findings also suggest that LeGRXS14 may act as a negative regulator in this process by exacerbating Na+ toxicity and the resulting oxidative stress.
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Affiliation(s)
- Lulu Liu
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China;
| | - Xiaofei Li
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310030, China; (X.L.); (M.S.); (J.S.); (Q.Z.)
| | - Mengke Su
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310030, China; (X.L.); (M.S.); (J.S.); (Q.Z.)
| | - Jiaping Shi
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310030, China; (X.L.); (M.S.); (J.S.); (Q.Z.)
| | - Qing Zhang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310030, China; (X.L.); (M.S.); (J.S.); (Q.Z.)
| | - Xunyan Liu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310030, China; (X.L.); (M.S.); (J.S.); (Q.Z.)
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Cassier-Chauvat C, Marceau F, Farci S, Ouchane S, Chauvat F. The Glutathione System: A Journey from Cyanobacteria to Higher Eukaryotes. Antioxidants (Basel) 2023; 12:1199. [PMID: 37371929 DOI: 10.3390/antiox12061199] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
From bacteria to plants and humans, the glutathione system plays a pleiotropic role in cell defense against metabolic, oxidative and metal stresses. Glutathione (GSH), the γ-L-glutamyl-L-cysteinyl-glycine nucleophile tri-peptide, is the central player of this system that acts in redox homeostasis, detoxification and iron metabolism in most living organisms. GSH directly scavenges diverse reactive oxygen species (ROS), such as singlet oxygen, superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide and carbon radicals. It also serves as a cofactor for various enzymes, such as glutaredoxins (Grxs), glutathione peroxidases (Gpxs), glutathione reductase (GR) and glutathione-S-transferases (GSTs), which play crucial roles in cell detoxication. This review summarizes what is known concerning the GSH-system (GSH, GSH-derived metabolites and GSH-dependent enzymes) in selected model organisms (Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana and human), emphasizing cyanobacteria for the following reasons. Cyanobacteria are environmentally crucial and biotechnologically important organisms that are regarded as having evolved photosynthesis and the GSH system to protect themselves against the ROS produced by their active photoautotrophic metabolism. Furthermore, cyanobacteria synthesize the GSH-derived metabolites, ergothioneine and phytochelatin, that play crucial roles in cell detoxication in humans and plants, respectively. Cyanobacteria also synthesize the thiol-less GSH homologs ophthalmate and norophthalmate that serve as biomarkers of various diseases in humans. Hence, cyanobacteria are well-suited to thoroughly analyze the role/specificity/redundancy of the players of the GSH-system using a genetic approach (deletion/overproduction) that is hardly feasible with other model organisms (E. coli and S. cerevisiae do not synthesize ergothioneine, while plants and humans acquire it from their soil and their diet, respectively).
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Affiliation(s)
- Corinne Cassier-Chauvat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Fanny Marceau
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Sandrine Farci
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Soufian Ouchane
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
| | - Franck Chauvat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), F-91190 Gif-sur-Yvette, France
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3
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The Intriguing Role of Iron-Sulfur Clusters in the CIAPIN1 Protein Family. INORGANICS 2022. [DOI: 10.3390/inorganics10040052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Iron-sulfur (Fe/S) clusters are protein cofactors that play a crucial role in essential cellular functions. Their ability to rapidly exchange electrons with several redox active acceptors makes them an efficient system for fulfilling diverse cellular needs. They include the formation of a relay for long-range electron transfer in enzymes, the biosynthesis of small molecules required for several metabolic pathways and the sensing of cellular levels of reactive oxygen or nitrogen species to activate appropriate cellular responses. An emerging family of iron-sulfur cluster binding proteins is CIAPIN1, which is characterized by a C-terminal domain of about 100 residues. This domain contains two highly conserved cysteine-rich motifs, which are both involved in Fe/S cluster binding. The CIAPIN1 proteins have been described so far to be involved in electron transfer pathways, providing electrons required for the biosynthesis of important protein cofactors, such as Fe/S clusters and the diferric-tyrosyl radical, as well as in the regulation of cell death. Here, we have first investigated the occurrence of CIAPIN1 proteins in different organisms spanning the entire tree of life. Then, we discussed the function of this family of proteins, focusing specifically on the role that the Fe/S clusters play. Finally, we describe the nature of the Fe/S clusters bound to CIAPIN1 proteins and which are the cellular pathways inserting the Fe/S clusters in the two cysteine-rich motifs.
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Spectroscopic and functional characterization of the [2Fe-2S] scaffold protein Nfu from Synechocystis PCC6803. Biochimie 2022; 192:51-62. [PMID: 34582998 PMCID: PMC8724361 DOI: 10.1016/j.biochi.2021.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 01/03/2023]
Abstract
Iron-sulfur clusters are ubiquitous cofactors required for various essential metabolic processes. Conservation of proteins required for their biosynthesis and trafficking allows for simple bacteria to be used as models to aid in exploring these complex pathways in higher organisms. Cyanobacteria are among the most investigated organisms for these processes, as they are unicellular and can survive under photoautotrophic and heterotrophic conditions. Herein, we report the potential role of Synechocystis PCC6803 NifU (now named SyNfu) as the principal scaffold protein required for iron-sulfur cluster biosynthesis in that organism. SyNfu is a well-folded protein with distinct secondary structural elements, as evidenced by circular dichroism and a well-dispersed pattern of 1H-15N HSQC NMR peaks, and readily reconstitutes as a [2Fe-2S] dimeric protein complex. Cluster exchange experiments show that glutathione can extract the cluster from holo-SyNfu, but the transfer is unidirectional. We also confirm the ability of SyNfu to transfer cluster to both human ferredoxin 1 and ferredoxin 2, while also demonstrating the capacity to deliver cluster to both monothiol glutaredoxin 3 and dithiol glutaredoxin 2. This evidence supports the hypothesis that SyNfu indeed serves as the main scaffold protein in Synechocystis, as it has been shown to be the only protein required for viability in the absence of photoautotrophic conditions. Similar to other NFU-type cluster donors and other scaffold and carrier proteins, such as ISCU, SyNfu is shown by DSC to be structurally less stable than regular protein donors, while retaining a relatively well-defined tertiary structure as represented by 1H-15N HSQC NMR experiments.
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A-type carrier proteins are involved in [4Fe-4S] cluster insertion into the radical SAM protein MoaA for the synthesis of active molybdoenzymes. J Bacteriol 2021; 203:e0008621. [PMID: 33782054 DOI: 10.1128/jb.00086-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Iron sulfur (Fe-S) clusters are important biological cofactors present in proteins with crucial biological functions, from photosynthesis to DNA repair, gene expression and bioenergetic processes. For the insertion of Fe-S clusters into proteins, A-type carrier proteins have been identified. So far, three of them were characterized in detail in Escherichia coli, namely IscA, SufA and ErpA, which were shown to partially replace each other in their roles in [4Fe-4S] cluster insertion into specific target proteins. To further expand the knowledge of [4Fe-4S] cluster insertion into proteins, we analyzed the complex Fe-S cluster dependent network for the synthesis of the molybdenum cofactor (Moco) and the expression of genes encoding nitrate reductase in E. coli Our studies include the identification of the A-type carrier proteins ErpA and IscA involved in [4Fe-4S] cluster insertion into the S-adenosyl-methionine dependent radical SAM protein MoaA. We show that ErpA and IscA can partially replace each other in their role to provide [4Fe-4S] clusters for MoaA. Since most genes expressing molybdoenzymes are regulated by the transcriptional regulator for fumarate and nitrate reduction (FNR) under anaerobic conditions, we also identified the proteins that are crucial to obtain an active FNR under conditions of nitrate respiration. We show that ErpA is essential for the FNR-dependent expression of the narGHJI operon, a role that cannot be compensated by IscA under the growth conditions tested. SufA does not have a role in Fe-S cluster insertion into MoaA or FNR under anaerobic growth of nitrate respiration, based on low gene expression levels.IMPORTANCEUnderstanding the assembly of iron-sulfur (Fe-S) proteins is relevant to many fields, including nitrogen fixation, photosynthesis, bioenergetics and gene regulation. Still remaining critical gaps in our knowledge are how Fe-S clusters are transferred to their target proteins and how the specificity in this process is achieved, since different forms of Fe-S clusters need to be delivered to structurally highly diverse target proteins. Numerous Fe-S carrier proteins have been identified in prokaryotes like Escherichia coli, including ErpA, IscA, SusA and NfuA. In addition, the diverse Fe-S cluster delivery proteins and their target proteins underlie a complex regulatory network of expression, to ensure that both proteins are synthesized under particular growth conditions.
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6
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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7
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Berndt C, Christ L, Rouhier N, Mühlenhoff U. Glutaredoxins with iron-sulphur clusters in eukaryotes - Structure, function and impact on disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148317. [PMID: 32980338 DOI: 10.1016/j.bbabio.2020.148317] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/07/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Among the thioredoxin superfamily of proteins, the observation that numerous glutaredoxins bind iron-sulphur (Fe/S) clusters is one of the more recent and major developments concerning their functional properties. Glutaredoxins are present in most organisms. All members of the class II subfamily (including most monothiol glutaredoxins), but also some members of the class I (mostly dithiol glutaredoxins) and class III (land plant-specific monothiol or dithiol glutaredoxins) are Fe/S proteins. In glutaredoxins characterised so far, the [2Fe2S] cluster is coordinated by two active-site cysteine residues and two molecules of non-covalently bound glutathione in homo-dimeric complexes bridged by the cluster. In contrast to dithiol glutaredoxins, monothiol glutaredoxins possess no or very little oxidoreductase activity, but have emerged as important players in cellular iron metabolism. In this review we summarise the recent developments of the most prominent Fe/S glutaredoxins in eukaryotes, the mitochondrial single domain monothiol glutaredoxin 5, the chloroplastic single domain monothiol glutaredoxin S14 and S16, the nuclear/cytosolic multi-domain monothiol glutaredoxin 3, and the mitochondrial/cytosolic dithiol glutaredoxin 2.
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Affiliation(s)
- Carsten Berndt
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Merowingerplatz1a, 40225 Düsseldorf, Germany
| | - Loïck Christ
- Université de Lorraine, INRAE, IAM, F-54000 Nancy, France
| | | | - Ulrich Mühlenhoff
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Str. 6, 35032 Marburg, Germany.
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8
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The Requirement of Inorganic Fe-S Clusters for the Biosynthesis of the Organometallic Molybdenum Cofactor. INORGANICS 2020. [DOI: 10.3390/inorganics8070043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Iron-sulfur (Fe-S) clusters are essential protein cofactors. In enzymes, they are present either in the rhombic [2Fe-2S] or the cubic [4Fe-4S] form, where they are involved in catalysis and electron transfer and in the biosynthesis of metal-containing prosthetic groups like the molybdenum cofactor (Moco). Here, we give an overview of the assembly of Fe-S clusters in bacteria and humans and present their connection to the Moco biosynthesis pathway. In all organisms, Fe-S cluster assembly starts with the abstraction of sulfur from l-cysteine and its transfer to a scaffold protein. After formation, Fe-S clusters are transferred to carrier proteins that insert them into recipient apo-proteins. In eukaryotes like humans and plants, Fe-S cluster assembly takes place both in mitochondria and in the cytosol. Both Moco biosynthesis and Fe-S cluster assembly are highly conserved among all kingdoms of life. Moco is a tricyclic pterin compound with molybdenum coordinated through its unique dithiolene group. Moco biosynthesis begins in the mitochondria in a Fe-S cluster dependent step involving radical/S-adenosylmethionine (SAM) chemistry. An intermediate is transferred to the cytosol where the dithiolene group is formed, to which molybdenum is finally added. Further connections between Fe-S cluster assembly and Moco biosynthesis are discussed in detail.
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9
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Molecular basis for the distinct functions of redox-active and FeS-transfering glutaredoxins. Nat Commun 2020; 11:3445. [PMID: 32651396 PMCID: PMC7351949 DOI: 10.1038/s41467-020-17323-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 06/18/2020] [Indexed: 02/08/2023] Open
Abstract
Despite their very close structural similarity, CxxC/S-type (class I) glutaredoxins (Grxs) act as oxidoreductases, while CGFS-type (class II) Grxs act as FeS cluster transferases. Here we show that the key determinant of Grx function is a distinct loop structure adjacent to the active site. Engineering of a CxxC/S-type Grx with a CGFS-type loop switched its function from oxidoreductase to FeS transferase. Engineering of a CGFS-type Grx with a CxxC/S-type loop abolished FeS transferase activity and activated the oxidative half reaction of the oxidoreductase. The reductive half-reaction, requiring the interaction with a second GSH molecule, was enabled by switching additional residues in the active site. We explain how subtle structural differences, mostly depending on the structure of one particular loop, act in concert to determine Grx function.
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Interactions of GMP with Human Glrx3 and with Saccharomyces cerevisiae Grx3 and Grx4 Converge in the Regulation of the Gcn2 Pathway. Appl Environ Microbiol 2020; 86:AEM.00221-20. [PMID: 32414791 DOI: 10.1128/aem.00221-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 04/24/2020] [Indexed: 11/20/2022] Open
Abstract
The human monothiol glutaredoxin Glrx3 (PICOT) is ubiquitously distributed in cytoplasm and nuclei in mammalian cells. Its overexpression has been associated with the development of several types of tumors, whereas its deficiency might cause retardation in embryogenesis. Its exact biological role has not been well resolved, although a function as a chaperone distributing iron/sulfur clusters is currently accepted. Yeast humanization and the use of a mouse library have allowed us to find a new partner for PICOT: the human GMP synthase (hGMPs). Both proteins carry out collaborative functions regarding the downregulation of the Saccharomyces cerevisiae Gcn2 pathway under conditions of nutritional stress. Glrx3/hGMPs interact through conserved residues that bridge iron/sulfur clusters and glutathione. This mechanism is also conserved in budding yeast, whose proteins Grx3/Grx4, along with GUA1 (S. cerevisiae GMPs), also downregulate the integrated stress response (ISR) pathway. The heterologous expression of Glrx3/hGMPs efficiently complements Grx3/Grx4. Moreover, the heterologous expression of Glrx3 efficiently complements the novel participation in chronological life span that has been characterized for both Grx3 and Grx4. Our results underscore that the Glrx3/Grx3/Grx4 family presents an evolutionary and functional conservation in signaling events that is partly related to GMP function and contributes to cell life extension.IMPORTANCE Saccharomyces cerevisiae is an optimal eukaryotic microbial model to study biological processes in higher organisms despite the divergence in evolution. The molecular function of yeast glutaredoxins Grx3 and Grx4 is enormously interesting, since both proteins are required to maintain correct iron homeostasis and an efficient response to oxidative stress. The human orthologous Glrx3 (PICOT) is involved in a number of human diseases, including cancer. Our research expanded its utility to human cells. Yeast has allowed the characterization of GMP synthase as a new interacting partner for Glrx3 and also for yeast Grx3 and Grx4, the complex monothiol glutaredoxins/GMPs that participate in the downregulation of the activity of the Gcn2 stress pathway. This mechanism is conserved in yeast and humans. Here, we also show that this family of glutaredoxins, Grx3/Grx4/Glrx3, also has a function related to life extension.
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Quantitative assessment of the determinant structural differences between redox-active and inactive glutaredoxins. Nat Commun 2020; 11:1725. [PMID: 32265442 PMCID: PMC7138851 DOI: 10.1038/s41467-020-15441-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/04/2020] [Indexed: 11/08/2022] Open
Abstract
Class I glutaredoxins are enzymatically active, glutathione-dependent oxidoreductases, whilst class II glutaredoxins are typically enzymatically inactive, Fe-S cluster-binding proteins. Enzymatically active glutaredoxins harbor both a glutathione-scaffold site for reacting with glutathionylated disulfide substrates and a glutathione-activator site for reacting with reduced glutathione. Here, using yeast ScGrx7 as a model protein, we comprehensively identified and characterized key residues from four distinct protein regions, as well as the covalently bound glutathione moiety, and quantified their contribution to both interaction sites. Additionally, we developed a redox-sensitive GFP2-based assay, which allowed the real-time assessment of glutaredoxin structure-function relationships inside living cells. Finally, we employed this assay to rapidly screen multiple glutaredoxin mutants, ultimately enabling us to convert enzymatically active and inactive glutaredoxins into each other. In summary, we have gained a comprehensive understanding of the mechanistic underpinnings of glutaredoxin catalysis and have elucidated the determinant structural differences between the two main classes of glutaredoxins. Glutaredoxins play a central role in numerous biological processes including cellular redox homeostasis and Fe-S cluster biogenesis. Here the authors establish the molecular basis for glutaredoxin redox catalysis through comprehensive biochemical and structural analyses.
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Mondal S, Kumar V, Singh SP. Phylogenetic distribution and structural analyses of cyanobacterial glutaredoxins (Grxs). Comput Biol Chem 2019; 84:107141. [PMID: 31839562 DOI: 10.1016/j.compbiolchem.2019.107141] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 11/18/2022]
Abstract
Glutaredoxins (Grxs), the oxidoreductase proteins, are involved in several cellular processes, including maintenance of cellular redox potential and iron-sulfur homeostasis. The analysis of 503 amino acid sequences from 167 cyanobacterial species led to the identification of four classes of cyanobacterial Grxs, i.e., class I, II, V, and VI Grxs. Class III and IV Grxs were absent in cyanobacteria. Class I and II Grxs are single module oxidoreductase while class V and VI Grxs are multimodular proteins having additional modules at their C-terminal and N-terminal end, respectively. Furthermore, class VI Grxs were exclusively present in marine cyanobacteria. We also report the identification of class VI Grxs with two novel active site motif compositions. Detailed phylogenetic analysis of all four classes of Grxs revealed the presence of several subgroups within each class of Grx having variable dithiol and/or monothiol catalytic active site motif and putative glutathione binding sites. However, class II Grxs possess CGFS-type highly conserved monothiol catalytic active site motif. Sequence analysis confirmed the highly diverse nature of Grx proteins in terms of their amino acid composition; though, sequence diversity does not affect the overall 3D structure of cyanobacterial Grxs. The active site residues and putative GSH binding residues are uncharged amino acids which are present on the surface of the protein. Additionally, the presence of hydrophilic residues at the surface of Grxs confirms their solubility. Protein-ligand interaction analysis identified novel glutathione binding sites on Grxs. Regulation of Grxs encoding genes expression by light quality and quantity as well as salinity suggests their role in determining the fitness of organisms under abiotic factors.
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Affiliation(s)
- Soumila Mondal
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, UP, India
| | - Vinod Kumar
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, UP, India
| | - Shailendra P Singh
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, UP, India.
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Kammerscheit X, Chauvat F, Cassier-Chauvat C. From Cyanobacteria to Human, MAPEG-Type Glutathione-S-Transferases Operate in Cell Tolerance to Heat, Cold, and Lipid Peroxidation. Front Microbiol 2019; 10:2248. [PMID: 31681188 PMCID: PMC6798054 DOI: 10.3389/fmicb.2019.02248] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/13/2019] [Indexed: 11/18/2022] Open
Abstract
The MAPEG2 sub-family of glutathione-S-transferase proteins (GST) has been poorly investigated in vivo, even in prokaryotes such as cyanobacteria the organisms that are regarded as having developed glutathione-dependent enzymes to protect themselves against the reactive oxygen species (ROS) often produced by their powerful photosynthesis. We report the first in vivo analysis of a cyanobacterial MAPEG2-like protein (Sll1147) in the model cyanobacterium Synechocystis PCC 6803. While Sll1147 is dispensable to cell growth in standard photo-autotrophic conditions, it plays an important role in the resistance to heat and cold, and to n-tertbutyl hydroperoxide (n-tBOOH) that induces lipid peroxidation. These findings suggest that Sll1147 could be involved in membrane fluidity, which is critical for photosynthesis. Attesting its sensitivity to these stresses, the Δsll1147 mutant lacking Sll1147 challenged by heat, cold, or n-tBOOH undergoes transient accumulation of peroxidized lipids and then of reduced and oxidized glutathione. These results are welcome because little is known concerning the signaling and/or protection mechanisms used by cyanobacteria to cope with heat and cold, two inevitable environmental stresses that limit their growth, and thus their production of biomass for our food chain and of biotechnologically interesting chemicals. Also interestingly, the decreased resistance to heat, cold and n-tBOOH of the Δsll1147 mutant could be rescued back to normal (wild-type) levels upon the expression of synthetic MAPEG2-encoding human genes adapted to the cyanobacterial codon usage. These synthetic hmGST2 and hmGST3 genes were also able to increase the Escherichia coli tolerance to heat and n-tBOOH. Collectively, these finding indicate that the activity of the MAPEG2 proteins have been conserved, at least in part, during evolution from (cyano)bacteria to human.
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Affiliation(s)
| | - Franck Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University of Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Corinne Cassier-Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University of Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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14
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Li H, Outten CE. The conserved CDC motif in the yeast iron regulator Aft2 mediates iron-sulfur cluster exchange and protein-protein interactions with Grx3 and Bol2. J Biol Inorg Chem 2019; 24:809-815. [PMID: 31493153 DOI: 10.1007/s00775-019-01705-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/20/2019] [Indexed: 10/26/2022]
Abstract
The Saccharomyces cerevisiae transcriptional activator Aft1 and its paralog Aft2 respond to iron deficiency by upregulating expression of proteins required for iron uptake at the plasma membrane, vacuolar iron transport, and mitochondrial iron metabolism, with the net result of mobilizing iron from extracellular sources and intracellular stores. Conversely, when iron levels are sufficient, Aft1 and Aft2 interact with the cytosolic glutaredoxins Grx3 and Grx4 and the BolA protein Bol2, which promote Aft1/2 dissociation from DNA and subsequent export from the nucleus. Previous studies unveiled the molecular mechanism for iron-dependent inhibition of Aft1/2 activity, demonstrating that the [2Fe-2S]-bridged Grx3-Bol2 heterodimer transfers a cluster to Aft2, driving Aft2 dimerization and dissociation from DNA. Here, we provide further insight into the regulation mechanism by investigating the roles of conserved cysteines in Aft2 in iron-sulfur cluster binding and interaction with [2Fe-2S]-Grx3-Bol2. Using size exclusion chromatography and circular dichroism spectroscopy, these studies reveal that both cysteines in the conserved Aft2 Cys-Asp-Cys motif are essential for Aft2 dimerization via [2Fe-2S] cluster binding, while only one cysteine is required for interaction with the [2Fe-2S]-Grx3-Bol2 complex. Taken together, these results provide novel insight into the molecular details of iron-sulfur cluster transfer from Grx3-Bol2 to Aft2 which likely occurs through a ligand exchange mechanism. Loss of either cysteine in the Aft2 iron-sulfur binding site may disrupt this ligand-exchange process leading to the isolation of a trapped Aft2-Grx3-Bol2 intermediate, while the replacement of both cysteines abrogates both the iron-sulfur cluster exchange and the protein-protein interactions between Aft2 and Grx3-Bol2.
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Affiliation(s)
- Haoran Li
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.,Kymera Therapeutics, Cambridge, MA, 02139, USA
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
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15
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Kumar A, Chauhan N, Singh S. Understanding the Cross-Talk of Redox Metabolism and Fe-S Cluster Biogenesis in Leishmania Through Systems Biology Approach. Front Cell Infect Microbiol 2019; 9:15. [PMID: 30778378 PMCID: PMC6369582 DOI: 10.3389/fcimb.2019.00015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/17/2019] [Indexed: 11/13/2022] Open
Abstract
Leishmania parasites possess an exceptional oxidant and chemical defense mechanism, involving a very unique small molecular weight thiol, trypanothione (T[SH]2), that helps the parasite to manage its survival inside the host macrophage. The reduced state of T[SH]2 is maintained by NADPH-dependent trypanothione reductase (TryR) by recycling trypanothione disulfide (TS2). Along with its most important role as central reductant, T[SH]2 have also been assumed to regulate the activation of iron-sulfur cluster proteins (Fe/S). Fe/S clusters are versatile cofactors of various proteins and execute a much broader range of essential biological processes viz., TCA cycle, redox homeostasis, etc. Although, several Fe/S cluster proteins and their roles have been identified in Leishmania, some of the components of how T[SH]2 is involved in the regulation of Fe/S proteins remains to be explored. In pursuit of this aim, a systems biology approach was undertaken to get an insight into the overall picture to unravel how T[SH]2 synthesis and reduction is linked with the regulation of Fe/S cluster proteins and controls the redox homeostasis at a larger scale. In the current study, we constructed an in silico kinetic model of T[SH]2 metabolism. T[SH]2 reduction reaction was introduced with a perturbation in the form of its inhibition to predict the overall behavior of the model. The main control of reaction fluxes were exerted by TryR reaction rate that affected almost all the important reactions in the model. It was observed that the model was more sensitive to the perturbation introduced in TryR reaction, 5 to 6-fold. Furthermore, due to inhibition, the T[SH]2 synthesis rate was observed to be gradually decreased by 8 to 14-fold. This has also caused an elevated level of free radicals which apparently affected the activation of Fe/S cluster proteins. The present kinetic model has demonstrated the importance of T[SH]2 in leishmanial cellular redox metabolism. Hence, we suggest that, by designing highly potent and specific inhibitors of TryR enzyme, inhibition of T[SH]2 reduction and overall inhibition of most of the downstream pathways including Fe/S protein activation reactions, can be accomplished.
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16
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Py B, Gerez C, Huguenot A, Vidaud C, Fontecave M, Ollagnier de Choudens S, Barras F. The ErpA/NfuA complex builds an oxidation-resistant Fe-S cluster delivery pathway. J Biol Chem 2018; 293:7689-7702. [PMID: 29626095 DOI: 10.1074/jbc.ra118.002160] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Indexed: 11/06/2022] Open
Abstract
Fe-S cluster-containing proteins occur in most organisms, wherein they assist in myriad processes from metabolism to DNA repair via gene expression and bioenergetic processes. Here, we used both in vitro and in vivo methods to investigate the capacity of the four Fe-S carriers, NfuA, SufA, ErpA, and IscA, to fulfill their targeting role under oxidative stress. Likewise, Fe-S clusters exhibited varying half-lives, depending on the carriers they were bound to; an NfuA-bound Fe-S cluster was more stable (t½ = 100 min) than those bound to SufA (t½ = 55 min), ErpA (t½ = 54 min), or IscA (t½ = 45 min). Surprisingly, the presence of NfuA further enhanced stability of the ErpA-bound cluster to t½ = 90 min. Using genetic and plasmon surface resonance analyses, we showed that NfuA and ErpA interacted directly with client proteins, whereas IscA or SufA did not. Moreover, NfuA and ErpA interacted with one another. Given all of these observations, we propose an architecture of the Fe-S delivery network in which ErpA is the last factor that delivers cluster directly to most if not all client proteins. NfuA is proposed to assist ErpA under severely unfavorable conditions. A comparison with the strategy employed in yeast and eukaryotes is discussed.
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Affiliation(s)
- Béatrice Py
- From the Institut de Microbiologie de la Méditerranée, 13009 Marseille, France, .,CNRS Unité Mixte de Recherche (UMR) 7283, Laboratoire de Chimie Bactérienne (LCB), 31 Chemin Joseph Aiguier, 13009 Marseille, France.,Aix-Marseille Université, 13007 Marseille, France
| | - Catherine Gerez
- Université Grenoble Alpes, 38400 Saint-Martin-d'Hères, France.,CNRS UMR 5249, Laboratoire de Chimie et Biologie des Métaux (LCBM), 38054 Grenoble, France.,CEA/DRF/BIG/CBM/BioCat, 38054 Grenoble, France
| | - Allison Huguenot
- From the Institut de Microbiologie de la Méditerranée, 13009 Marseille, France.,CNRS Unité Mixte de Recherche (UMR) 7283, Laboratoire de Chimie Bactérienne (LCB), 31 Chemin Joseph Aiguier, 13009 Marseille, France.,Aix-Marseille Université, 13007 Marseille, France
| | | | - Marc Fontecave
- the Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie (UPMC) Université Paris 06, Collège de France, Paris Sciences et Lettres (PSL) Research University, 75252 Paris, France
| | - Sandrine Ollagnier de Choudens
- Université Grenoble Alpes, 38400 Saint-Martin-d'Hères, France.,CNRS UMR 5249, Laboratoire de Chimie et Biologie des Métaux (LCBM), 38054 Grenoble, France.,CEA/DRF/BIG/CBM/BioCat, 38054 Grenoble, France
| | - Frédéric Barras
- From the Institut de Microbiologie de la Méditerranée, 13009 Marseille, France, .,CNRS Unité Mixte de Recherche (UMR) 7283, Laboratoire de Chimie Bactérienne (LCB), 31 Chemin Joseph Aiguier, 13009 Marseille, France.,Aix-Marseille Université, 13007 Marseille, France
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17
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Abstract
SIGNIFICANCE Since the discovery and structural characterization of bacillithiol (BSH), the biochemical functions of BSH-biosynthesis enzymes (BshA/B/C) and BSH-dependent detoxification enzymes (FosB, Bst, GlxA/B) have been explored in Bacillus and Staphylococcus species. It was shown that BSH plays an important role in detoxification of reactive oxygen and electrophilic species, alkylating agents, toxins, and antibiotics. Recent Advances: More recently, new functions of BSH were discovered in metal homeostasis (Zn buffering, Fe-sulfur cluster, and copper homeostasis) and virulence control in Staphylococcus aureus. Unexpectedly, strains of the S. aureus NCTC8325 lineage were identified as natural BSH-deficient mutants. Modern mass spectrometry-based approaches have revealed the global reach of protein S-bacillithiolation in Firmicutes as an important regulatory redox modification under hypochlorite stress. S-bacillithiolation of OhrR, MetE, and glyceraldehyde-3-phosphate dehydrogenase (Gap) functions, analogous to S-glutathionylation, as both a redox-regulatory device and in thiol protection under oxidative stress. CRITICAL ISSUES Although the functions of the bacilliredoxin (Brx) pathways in the reversal of S-bacillithiolations have been recently addressed, significantly more work is needed to establish the complete Brx reduction pathway, including the major enzyme(s), for reduction of oxidized BSH (BSSB) and the targets of Brx action in vivo. FUTURE DIRECTIONS Despite the large number of identified S-bacillithiolated proteins, the physiological relevance of this redox modification was shown for only selected targets and should be a subject of future studies. In addition, many more BSH-dependent detoxification enzymes are evident from previous studies, although their roles and biochemical mechanisms require further study. This review of BSH research also pin-points these missing gaps for future research. Antioxid. Redox Signal. 28, 445-462.
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Affiliation(s)
- Pete Chandrangsu
- 1 Department of Microbiology, Cornell University , Ithaca, New York
| | - Vu Van Loi
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - Haike Antelmann
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - John D Helmann
- 1 Department of Microbiology, Cornell University , Ithaca, New York
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18
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Investigation of glutathione-derived electrostatic and hydrogen-bonding interactions and their role in defining Grx5 [2Fe-2S] cluster optical spectra and transfer chemistry. J Biol Inorg Chem 2017; 23:241-252. [PMID: 29264659 DOI: 10.1007/s00775-017-1525-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/13/2017] [Indexed: 01/23/2023]
Abstract
Human glutaredoxin 5 (Grx5) is one of the core components of the Isc (iron-sulfur cluster) assembly and trafficking machinery, and serves as an intermediary cluster carrier, putatively delivering cluster from the Isu scaffold protein to target proteins. The tripeptide glutathione is intimately involved in this role, providing cysteinyl coordination to the iron center of the Grx5-bound [2Fe-2S] cluster. Grx5 has a well-defined glutathione-binding pocket with protein amino acid residues providing many ionic and hydrogen binding contacts to the bound glutathione. In this report, we investigated the importance of these interactions in cluster chirality and exchange reactivity by systematically perturbing the crucial contacts by use of natural and non-natural amino acid substitutions to disrupt the binding contacts from both the protein and glutathione. Native Grx5 could be reconstituted with all of the glutathione analogs used, as well as other thiol ligands, such as DTT or L-cysteine, by in vitro chemical reconstitution, and the holo proteins were found to transfer [2Fe-2S] cluster to apo ferredoxin 1 at comparable rates. However, the circular dichroism spectra of these derivatives displayed prominent differences that reflect perturbations in local cluster chirality. These studies provided a detailed molecular understanding of glutathione-protein interactions in holo Grx5 that define both cluster spectroscopy and exchange chemistry.
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19
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Abstract
SIGNIFICANCE Glutathione metabolism is comparable to a jigsaw puzzle with too many pieces. It is supposed to comprise (i) the reduction of disulfides, hydroperoxides, sulfenic acids, and nitrosothiols, (ii) the detoxification of aldehydes, xenobiotics, and heavy metals, and (iii) the synthesis of eicosanoids, steroids, and iron-sulfur clusters. In addition, glutathione affects oxidative protein folding and redox signaling. Here, I try to provide an overview on the relevance of glutathione-dependent pathways with an emphasis on quantitative data. Recent Advances: Intracellular redox measurements reveal that the cytosol, the nucleus, and mitochondria contain very little glutathione disulfide and that oxidative challenges are rapidly counterbalanced. Genetic approaches suggest that iron metabolism is the centerpiece of the glutathione puzzle in yeast. Furthermore, recent biochemical studies provide novel insights on glutathione transport processes and uncoupling mechanisms. CRITICAL ISSUES Which parts of the glutathione puzzle are most relevant? Does this explain the high intracellular concentrations of reduced glutathione? How can iron-sulfur cluster biogenesis, oxidative protein folding, or redox signaling occur at high glutathione concentrations? Answers to these questions not only seem to depend on the organism, cell type, and subcellular compartment but also on different ideologies among researchers. FUTURE DIRECTIONS A rational approach to compare the relevance of glutathione-dependent pathways is to combine genetic and quantitative kinetic data. However, there are still many missing pieces and too little is known about the compartment-specific repertoire and concentration of numerous metabolites, substrates, enzymes, and transporters as well as rate constants and enzyme kinetic patterns. Gathering this information might require the development of novel tools but is crucial to address potential kinetic competitions and to decipher uncoupling mechanisms to solve the glutathione puzzle. Antioxid. Redox Signal. 27, 1130-1161.
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Affiliation(s)
- Marcel Deponte
- Department of Parasitology, Ruprecht-Karls University , Heidelberg, Germany
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20
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Abstract
SIGNIFICANCE Glutathione (GSH) is the most abundant cellular low-molecular-weight thiol in the majority of organisms in all kingdoms of life. Therefore, functions of GSH and disturbed regulation of its concentration are associated with numerous physiological and pathological situations. Recent Advances: The function of GSH as redox buffer or antioxidant is increasingly being questioned. New functions, especially functions connected to the cellular iron homeostasis, were elucidated. Via the formation of iron complexes, GSH is an important player in all aspects of iron metabolism: sensing and regulation of iron levels, iron trafficking, and biosynthesis of iron cofactors. The variety of GSH coordinated iron complexes and their functions with a special focus on FeS-glutaredoxins are summarized in this review. Interestingly, GSH analogues that function as major low-molecular-weight thiols in organisms lacking GSH resemble the functions in iron homeostasis. CRITICAL ISSUES Since these iron-related functions are most likely also connected to thiol redox chemistry, it is difficult to distinguish between mechanisms related to either redox or iron metabolisms. FUTURE DIRECTIONS The ability of GSH to coordinate iron in different complexes with or without proteins needs further investigation. The discovery of new Fe-GSH complexes and their physiological functions will significantly advance our understanding of cellular iron homeostasis. Antioxid. Redox Signal. 27, 1235-1251.
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Affiliation(s)
- Carsten Berndt
- 1 Department of Neurology, Medical Faculty, Life Science Center , Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Christopher Horst Lillig
- 2 Institute for Medical Biochemistry and Molecular Biology, University Medicine Greifswald , Greifswald, Germany
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21
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Dutkiewicz R, Nowak M. Molecular chaperones involved in mitochondrial iron-sulfur protein biogenesis. J Biol Inorg Chem 2017; 23:569-579. [PMID: 29124426 PMCID: PMC6006194 DOI: 10.1007/s00775-017-1504-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/28/2017] [Indexed: 12/16/2022]
Abstract
Iron-sulfur (FeS) clusters are prosthetic groups critical for the function of many proteins in all domains of life. FeS proteins function in processes ranging from oxidative phosphorylation and cofactor biosyntheses to DNA/RNA metabolism and regulation of gene expression. In eukaryotic cells, mitochondria play a central role in the process of FeS biogenesis and support maturation of FeS proteins localized within mitochondria and in other cellular compartments. In humans, defects in mitochondrial FeS cluster biogenesis lead to numerous pathologies, which are often fatal. The generation of FeS clusters in mitochondria is a complex process. The [2Fe-2S] cluster is first assembled on a dedicated scaffold protein (Isu1) by the action of protein factors that interact with Isu1 to form the "assembly complex". Next, the FeS cluster is transferred onto a recipient apo-protein. Genetic and biochemical evidence implicates participation of a specialized J-protein co-chaperone Jac1 and its mitochondrial (mt)Hsp70 chaperone partner, and the glutaredoxin Grx5 in the FeS cluster transfer process. Finally, various specialized ISC components assist in the generation of [4Fe-4S] clusters and cluster insertion into specific target apoproteins. Although a framework of protein components that are involved in the mitochondrial FeS cluster biogenesis has been established based on genetic and biochemical studies, detailed molecular mechanisms involved in this important and medically relevant process are not well understood. This review summarizes our molecular knowledge on chaperone proteins' functions during the FeS protein biogenesis.
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Affiliation(s)
- Rafal Dutkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland.
| | - Malgorzata Nowak
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland
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22
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Role of protein-glutathione contacts in defining glutaredoxin-3 [2Fe–2S] cluster chirality, ligand exchange and transfer chemistry. J Biol Inorg Chem 2017; 22:1075-1087. [DOI: 10.1007/s00775-017-1485-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/16/2017] [Indexed: 01/27/2023]
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23
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24
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Dlouhy AC, Beaudoin J, Labbé S, Outten CE. Schizosaccharomyces pombe Grx4 regulates the transcriptional repressor Php4 via [2Fe-2S] cluster binding. Metallomics 2017; 9:1096-1105. [PMID: 28725905 DOI: 10.1039/c7mt00144d] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The fission yeast Schizosaccharomyces pombe expresses the CCAAT-binding factor Php4 in response to iron deprivation. Php4 forms a transcription complex with Php2, Php3, and Php5 to repress the expression of iron proteins as a means to economize iron usage. Previous in vivo results demonstrate that the function and location of Php4 are regulated in an iron-dependent manner by the cytosolic CGFS type glutaredoxin Grx4. In this study, we aimed to biochemically define these protein-protein and protein-metal interactions. Grx4 was found to bind a [2Fe-2S] cluster with spectroscopic features similar to other CGFS glutaredoxins. Grx4 and Php4 also copurify as a complex with a [2Fe-2S] cluster that is spectroscopically distinct from the cluster on Grx4 alone. In vitro titration experiments suggest that these Fe-S complexes may not be interconvertible in the absence of additional factors. Furthermore, conserved cysteines in Grx4 (Cys172) and Php4 (Cys221 and Cys227) are necessary for Fe-S cluster binding and stable complex formation. Together, these results show that Grx4 controls Php4 function through binding of a bridging [2Fe-2S] cluster.
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Affiliation(s)
- Adrienne C Dlouhy
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, USA.
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25
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Remelli W, Santabarbara S, Carbonera D, Bonomi F, Ceriotti A, Casazza AP. Iron Binding Properties of Recombinant Class A Protein Disulfide Isomerase from Arabidopsis thaliana. Biochemistry 2017; 56:2116-2125. [DOI: 10.1021/acs.biochem.6b01257] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- William Remelli
- Istituto
di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
- Istituto
di Biofisica, Consiglio Nazionale delle Ricerche, Via Celoria
26, 20133 Milano, Italy
| | - Stefano Santabarbara
- Istituto
di Biofisica, Consiglio Nazionale delle Ricerche, Via Celoria
26, 20133 Milano, Italy
| | - Donatella Carbonera
- Dipartimento
di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Francesco Bonomi
- Dipartimento
di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, DeFENS, Università di Milano, Via G. Celoria 2, 20133 Milano, Italy
| | - Aldo Ceriotti
- Istituto
di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
| | - Anna Paola Casazza
- Istituto
di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
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26
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Pujol-Carrion N, Torre-Ruiz MADL. Physical interaction between the MAPK Slt2 of the PKC1-MAPK pathway and Grx3/Grx4 glutaredoxins is required for the oxidative stress response in budding yeast. Free Radic Biol Med 2017; 103:107-120. [PMID: 28007574 DOI: 10.1016/j.freeradbiomed.2016.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 12/02/2016] [Accepted: 12/18/2016] [Indexed: 01/20/2023]
Abstract
This study demonstrates that both monothiol glutaredoxins Grx3 and Grx4 physically interact with the MAPK Slt2 forming a complex involved in the cellular response to oxidative stress. The simultaneous absence of Grx3 and Grx4 provokes a serious impairment in cell viability, Slt2 activation and Rlm1 transcription in response to oxidative stress. Both in vivo and in vitro results clearly show that Slt2 can independently bind either Grx3 or Grx4 proteins. Our results suggest that Slt2 form iron/sulphur bridged clusters with Grx3 and Grx4. For the assembly of this complex, cysteines of the active site of each Grx3/4 glutaredoxins, glutathione and specific cysteine residues from Slt2 provide the ligands. One of the ligands of Slt2 is required for its dimerisation upon oxidative treatment and iron repletion. These interactions are relevant for the oxidative response, given that mutants in the cysteine ligands identified in the complex show a severe impairment of both cell viability and Slt2 phosphorylation upon oxidative stress. Grx4 is the relevant glutaredoxin that regulates Slt2 phosphorylation under oxidative conditions precluding cell survival. Our studies contribute to extend the functions of both monothiol glutaredoxins to the regulation of a MAPK in the context of the oxidative stress response.
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Affiliation(s)
- Nuria Pujol-Carrion
- Department of Basic Medical Sciences, IRB-Lleida. University of Lleida, Av. Alcalde Rovira Roure no 80, 25198 Lleida, Spain
| | - Maria Angeles de la Torre-Ruiz
- Department of Basic Medical Sciences, IRB-Lleida. University of Lleida, Av. Alcalde Rovira Roure no 80, 25198 Lleida, Spain.
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27
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Nagels Durand A, Iñigo S, Ritter A, Iniesto E, De Clercq R, Staes A, Van Leene J, Rubio V, Gevaert K, De Jaeger G, Pauwels L, Goossens A. The Arabidopsis Iron-Sulfur Protein GRXS17 is a Target of the Ubiquitin E3 Ligases RGLG3 and RGLG4. PLANT & CELL PHYSIOLOGY 2016; 57:1801-1813. [PMID: 27497447 DOI: 10.1093/pcp/pcw122] [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: 03/31/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
The stability of signaling proteins in eukaryotes is often controlled by post-translational modifiers. For polyubiquitination, specificity is assured by E3 ubiquitin ligases. Although plant genomes encode hundreds of E3 ligases, only few targets are known, even in the model Arabidopsis thaliana. Here, we identified the monothiol glutaredoxin GRXS17 as a substrate of the Arabidopsis E3 ubiquitin ligases RING DOMAIN LIGASE 3 (RGLG3) and RGLG4 using a substrate trapping approach involving tandem affinity purification of RING-dead versions. Simultaneously, we used a ubiquitin-conjugating enzym (UBC) panel screen to pinpoint UBC30 as a cognate E2 UBC capable of interacting with RGLG3 and RGLG4 and mediating auto-ubiquitination of RGLG3 and ubiquitination of GRXS17 in vitro. Accordingly, GRXS17 is ubiquitinated and degraded in an RGLG3- and RGLG4-dependent manner in planta. The truncated hemoglobin GLB3 also interacted with RGLG3 and RGLG4 but appeared to obstruct RGLG3 ubiquitination activity rather than being its substrate. Our results suggest that the RGLG family is intimately linked to the essential element iron.
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Affiliation(s)
- Astrid Nagels Durand
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium These authors contributed equally to this work
| | - Sabrina Iñigo
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium These authors contributed equally to this work
| | - Andrés Ritter
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - Elisa Iniesto
- Plant Molecular Genetics Department, National Centre for Biotechnology (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus Universidad Autónoma, Madrid, Spain
| | - Rebecca De Clercq
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - An Staes
- Medical Biotechnology Center, VIB, B-9000 Ghent, Belgium Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Jelle Van Leene
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - Vicente Rubio
- Plant Molecular Genetics Department, National Centre for Biotechnology (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus Universidad Autónoma, Madrid, Spain
| | - Kris Gevaert
- Medical Biotechnology Center, VIB, B-9000 Ghent, Belgium Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - Laurens Pauwels
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium These authors contributed equally to this work
| | - Alain Goossens
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium These authors contributed equally to this work.
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28
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Kim HJ, Lee KL, Kim KD, Roe JH. The iron uptake repressor Fep1 in the fission yeast binds Fe-S cluster through conserved cysteines. Biochem Biophys Res Commun 2016; 478:187-192. [DOI: 10.1016/j.bbrc.2016.07.070] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/16/2016] [Indexed: 11/29/2022]
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29
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Wachnowsky C, Fidai I, Cowan JA. Iron-sulfur cluster exchange reactions mediated by the human Nfu protein. J Biol Inorg Chem 2016; 21:825-836. [PMID: 27538573 DOI: 10.1007/s00775-016-1381-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/26/2016] [Indexed: 01/06/2023]
Abstract
Human Nfu is an iron-sulfur cluster protein that has recently been implicated in multiple mitochondrial dysfunctional syndrome (MMDS1). The Nfu family of proteins shares a highly homologous domain that contains a conserved active site consisting of a CXXC motif. There is less functional conservation between bacterial and human Nfu proteins, particularly concerning their Iron-sulfur cluster binding and transfer roles. Herein, we characterize the cluster exchange chemistry of human Nfu and its capacity to bind and transfer a [2Fe-2S] cluster. The mechanism of cluster uptake from a physiologically relevant [2Fe-2S](GS)4 cluster complex, and extraction of the Nfu-bound iron-sulfur cluster by glutathione are described. Human holo Nfu shows a dimer-tetramer equilibrium with a protein to cluster ratio of 2:1, reflecting the Nfu-bridging [2Fe-2S] cluster. This cluster can be transferred to apo human ferredoxins at relatively fast rates, demonstrating a direct role for human Nfu in the process of [2Fe-2S] cluster trafficking and delivery.
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Affiliation(s)
- Christine Wachnowsky
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, USA
| | - Insiya Fidai
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
- The Biophysics Graduate Program, The Ohio State University, Columbus, USA
| | - J A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, USA
- The Biophysics Graduate Program, The Ohio State University, Columbus, USA
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30
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Narainsamy K, Farci S, Braun E, Junot C, Cassier-Chauvat C, Chauvat F. Oxidative-stress detoxification and signalling in cyanobacteria: the crucial glutathione synthesis pathway supports the production of ergothioneine and ophthalmate. Mol Microbiol 2016; 100:15-24. [DOI: 10.1111/mmi.13296] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Kinsley Narainsamy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay; 91198 Gif-sur-Yvette cedex France
| | - Sandrine Farci
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay; 91198 Gif-sur-Yvette cedex France
| | - Emilie Braun
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay; 91198 Gif-sur-Yvette cedex France
| | - Christophe Junot
- CEA, iBiTec-S, SPI, LEMM, Bat 136 CEA-Saclay; F-91191 Gif sur Yvette cedex France
| | - Corinne Cassier-Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay; 91198 Gif-sur-Yvette cedex France
| | - Franck Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay; 91198 Gif-sur-Yvette cedex France
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31
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Xiong Q, Chen Z, Ge F. Proteomic analysis of post translational modifications in cyanobacteria. J Proteomics 2016; 134:57-64. [DOI: 10.1016/j.jprot.2015.07.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 06/28/2015] [Accepted: 07/30/2015] [Indexed: 01/16/2023]
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Banci L, Camponeschi F, Ciofi-Baffoni S, Muzzioli R. Elucidating the Molecular Function of Human BOLA2 in GRX3-Dependent Anamorsin Maturation Pathway. J Am Chem Soc 2015; 137:16133-43. [PMID: 26613676 DOI: 10.1021/jacs.5b10592] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In eukaryotes, the interaction between members of the monothiol glutaredoxin family and members of the BolA-like protein family has been involved in iron metabolism. To investigate the still unknown functional role of the interaction between human glutaredoxin-3 (GRX3) and its protein partner BOLA2, we characterized at the atomic level the interaction of apo BOLA2 with the apo and holo states of GRX3 and studied the role of BOLA2 in the GRX3-dependent anamorsin maturation pathway. From these studies, it emerged that apo GRX3 and apo BOLA2 form a heterotrimeric complex, composed by two BOLA2 molecules and one GRX3 molecule. This complex is able to bind two [2Fe-2S](2+) clusters, each being bridged between a BOLA2 molecule and a monothiol glutaredoxin domain of GRX3, and to transfer both [2Fe-2S](2+) clusters to apo anamorsin producing its mature holo state. Collectively, the data suggest that the heterotrimeric complex can work as a [2Fe-2S](2+) cluster transfer component in cytosolic Fe/S protein maturation pathways.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM, University of Florence , Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.,Department of Chemistry, University of Florence , Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Francesca Camponeschi
- Magnetic Resonance Center CERM, University of Florence , Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.,Department of Chemistry, University of Florence , Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center CERM, University of Florence , Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.,Department of Chemistry, University of Florence , Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Riccardo Muzzioli
- Magnetic Resonance Center CERM, University of Florence , Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.,Department of Chemistry, University of Florence , Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
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The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2015; 112:13735-40. [PMID: 26483494 DOI: 10.1073/pnas.1510835112] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The iron-sulfur cluster (ISC) is an ancient and essential cofactor of many proteins involved in electron transfer and metabolic reactions. In Arabidopsis, three pathways exist for the maturation of iron-sulfur proteins in the cytosol, plastids, and mitochondria. We functionally characterized the role of mitochondrial glutaredoxin S15 (GRXS15) in biogenesis of ISC containing aconitase through a combination of genetic, physiological, and biochemical approaches. Two Arabidopsis T-DNA insertion mutants were identified as null mutants with early embryonic lethal phenotypes that could be rescued by GRXS15. Furthermore, we showed that recombinant GRXS15 is able to coordinate and transfer an ISC and that this coordination depends on reduced glutathione (GSH). We found the Arabidopsis GRXS15 able to complement growth defects based on disturbed ISC protein assembly of a yeast Δgrx5 mutant. Modeling of GRXS15 onto the crystal structures of related nonplant proteins highlighted amino acid residues that after mutation diminished GSH and subsequently ISC coordination, as well as the ability to rescue the yeast mutant. When used for plant complementation, one of these mutant variants, GRXS15K83/A, led to severe developmental delay and a pronounced decrease in aconitase activity by approximately 65%. These results indicate that mitochondrial GRXS15 is an essential protein in Arabidopsis, required for full activity of iron-sulfur proteins.
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Couturier J, Przybyla-Toscano J, Roret T, Didierjean C, Rouhier N. The roles of glutaredoxins ligating Fe–S clusters: Sensing, transfer or repair functions? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1513-27. [DOI: 10.1016/j.bbamcr.2014.09.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 01/05/2023]
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35
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Responses to oxidative and heavy metal stresses in cyanobacteria: recent advances. Int J Mol Sci 2014; 16:871-86. [PMID: 25561236 PMCID: PMC4307280 DOI: 10.3390/ijms16010871] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 12/24/2014] [Indexed: 12/24/2022] Open
Abstract
Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk.
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36
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Li S. Redox Modulation Matters: Emerging Functions for Glutaredoxins in Plant Development and Stress Responses. PLANTS 2014; 3:559-82. [PMID: 27135520 PMCID: PMC4844277 DOI: 10.3390/plants3040559] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/07/2014] [Accepted: 11/13/2014] [Indexed: 11/18/2022]
Abstract
Glutaredoxins (GRXs) are small ubiquitous glutathione (GSH)-dependent oxidoreductases that catalyze the reversible reduction of protein disulfide bridges or protein-GSH mixed disulfide bonds via a dithiol or monothiol mechanism, respectively. Three major classes of GRXs, with the CPYC-type, the CGFS-type or the CC-type active site, have been identified in many plant species. In spite of the well-characterized roles for GRXs in Escherichia coli, yeast and humans, the biological functions of plant GRXs have been largely enigmatic. The CPYC-type and CGFS-type GRXs exist in all organisms, from prokaryotes to eukaryotes, whereas the CC-type class has thus far been solely identified in land plants. Only the number of the CC-type GRXs has enlarged dramatically during the evolution of land plants, suggesting their participation in the formation of more complex plants adapted to life on land. A growing body of evidence indicates that plant GRXs are involved in numerous cellular pathways. In this review, emphasis is placed on the recently emerging functions for GRXs in floral organ development and disease resistance. Notably, CC-type GRXs have been recruited to participate in these two seemingly unrelated processes. Besides, the current knowledge of plant GRXs in the assembly and delivery of iron-sulfur clusters, oxidative stress responses and arsenic resistance is also presented. As GRXs require GSH as an electron donor to reduce their target proteins, GSH-related developmental processes, including the control of flowering time and the development of postembryonic roots and shoots, are further discussed. Profiling the thiol redox proteome using high-throughput proteomic approaches and measuring cellular redox changes with fluorescent redox biosensors will help to further unravel the redox-regulated physiological processes in plants.
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Affiliation(s)
- Shutian Li
- Department of Botany, Osnabrück University, 49076 Osnabrück, Germany.
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37
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Giner-Lamia J, López-Maury L, Florencio FJ. Global transcriptional profiles of the copper responses in the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2014; 9:e108912. [PMID: 25268225 PMCID: PMC4182526 DOI: 10.1371/journal.pone.0108912] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/27/2014] [Indexed: 12/22/2022] Open
Abstract
Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport system, CopBAC and a protein of unknown function, CopM. Here, we report the transcriptional responses to copper additions at non-toxic (0.3 µM) and toxic concentrations (3 µM) in the wild type and in the copper sensitive copR mutant strain. While 0.3 µM copper slightly stimulated metabolism and promoted the exchange between cytochrome c6 and plastocyanin as soluble electron carriers, the addition of 3 µM copper catalyzed the formation of ROS, led to a general stress response and induced expression of Fe-S cluster biogenesis genes. According to this, a double mutant strain copRsufR, which expresses constitutively the sufBCDS operon, tolerated higher copper concentration than the copR mutant strain, suggesting that Fe-S clusters are direct targets of copper toxicity in Synechocystis. In addition we have also demonstrated that InrS, a nickel binding transcriptional repressor that belong to the CsoR family of transcriptional factor, was involved in heavy metal homeostasis, including copper, in Synechocystis. Finally, global gene expression analysis of the copR mutant strain suggested that CopRS only controls the expression of copMRS and copBAC operons in response to copper.
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Affiliation(s)
- Joaquin Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
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38
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Chardonnet S, Sakr S, Cassier-Chauvat C, Le Maréchal P, Chauvat F, Lemaire SD, Decottignies P. First proteomic study of S-glutathionylation in cyanobacteria. J Proteome Res 2014; 14:59-71. [PMID: 25208982 DOI: 10.1021/pr500625a] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glutathionylation, the reversible post-translational formation of a mixed disulfide between a cysteine residue and glutathione (GSH), is a crucial mechanism for signal transduction and regulation of protein function. Until now this reversible redox modification was studied mainly in eukaryotic cells. Here we report a large-scale proteomic analysis of glutathionylation in a photosynthetic prokaryote, the model cyanobacterium Synechocystis sp. PCC6803. Treatment of acellular extracts with N,N-biotinyl glutathione disulfide (BioGSSG) induced glutathionylation of numerous proteins, which were subsequently isolated by affinity chromatography on streptavidin columns and identified by nano LC-MS/MS analysis. Potential sites of glutathionylation were also determined for 125 proteins following tryptic cleavage, streptavidin-affinity purification, and mass spectrometry analysis. Taken together the two approaches allowed the identification of 383 glutathionylatable proteins that participate in a wide range of cellular processes and metabolic pathways such as carbon and nitrogen metabolisms, cell division, stress responses, and H2 production. In addition, the glutathionylation of two putative targets, namely, peroxiredoxin (Sll1621) involved in oxidative stress tolerance and 3-phosphoglycerate dehydrogenase (Sll1908) acting on amino acids metabolism, was confirmed by biochemical studies on the purified recombinant proteins. These results suggest that glutathionylation constitutes a major mechanism of global regulation of the cyanobacterial metabolism under oxidative stress conditions.
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Gsaller F, Hortschansky P, Beattie SR, Klammer V, Tuppatsch K, Lechner BE, Rietzschel N, Werner ER, Vogan AA, Chung D, Mühlenhoff U, Kato M, Cramer RA, Brakhage AA, Haas H. The Janus transcription factor HapX controls fungal adaptation to both iron starvation and iron excess. EMBO J 2014; 33:2261-76. [PMID: 25092765 PMCID: PMC4232046 DOI: 10.15252/embj.201489468] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Balance of physiological levels of iron is essential for every organism. In Aspergillus fumigatus and other fungal pathogens, the transcription factor HapX mediates adaptation to iron limitation and consequently virulence by repressing iron consumption and activating iron uptake. Here, we demonstrate that HapX is also essential for iron resistance via activating vacuolar iron storage. We identified HapX protein domains that are essential for HapX functions during either iron starvation or high-iron conditions. The evolutionary conservation of these domains indicates their wide-spread role in iron sensing. We further demonstrate that a HapX homodimer and the CCAAT-binding complex (CBC) cooperatively bind an evolutionary conserved DNA motif in a target promoter. The latter reveals the mode of discrimination between general CBC and specific HapX/CBC target genes. Collectively, our study uncovers a novel regulatory mechanism mediating both iron resistance and adaptation to iron starvation by the same transcription factor complex with activating and repressing functions depending on ambient iron availability.
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Affiliation(s)
- Fabio Gsaller
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Peter Hortschansky
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Sarah R Beattie
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Veronika Klammer
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Katja Tuppatsch
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany Friedrich Schiller University, Jena, Germany
| | - Beatrix E Lechner
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Nicole Rietzschel
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Marburg, Germany
| | - Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Aaron A Vogan
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Dawoon Chung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Ulrich Mühlenhoff
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Marburg, Germany
| | - Masashi Kato
- Faculty of Agriculture, Meijo University, Nagoya, Japan
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany Friedrich Schiller University, Jena, Germany
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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Jacques JF, Mercier A, Brault A, Mourer T, Labbé S. Fra2 is a co-regulator of Fep1 inhibition in response to iron starvation. PLoS One 2014; 9:e98959. [PMID: 24897379 PMCID: PMC4045890 DOI: 10.1371/journal.pone.0098959] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 05/08/2014] [Indexed: 01/12/2023] Open
Abstract
Iron is required for several metabolic functions involved in cellular growth. Although several players involved in iron transport have been identified, the mechanisms by which iron-responsive transcription factors are controlled are still poorly understood. In Schizosaccharomyces pombe, the Fep1 transcription factor represses genes involved in iron acquisition in response to high levels of iron. In contrast, when iron levels are low, Fep1 becomes inactive and loses its ability to associate with chromatin. Although the molecular basis by which Fep1 is inactivated under iron starvation remains unknown, this process requires the monothiol glutaredoxin Grx4. Here, we demonstrate that Fra2 plays a role in the negative regulation of Fep1 activity. Disruption of fra2+ (fra2Δ) led to a constitutive repression of the fio1+ gene transcription. Fep1 was consistently active and constitutively bound to its target gene promoters in cells lacking fra2+. A constitutive activation of Fep1 was also observed in a php4Δ fra2Δ double mutant strain in which the behavior of Fep1 is freed of its transcriptional regulation by Php4. Microscopic analyses of cells expressing a functional Fra2-Myc13 protein revealed that Fra2 localized throughout the cells with a significant proportion of Fra2 being observed within the nuclei. Further analysis by coimmunoprecipitation showed that Fra2, Fep1 and Grx4 are associated in a heteroprotein complex. Bimolecular fluorescence complementation experiments brought further evidence that an interaction between Fep1 and Fra2 occurs in the nucleus. Taken together, results reported here revealed that Fra2 plays a role in the Grx4-mediated pathway that inactivates Fep1 in response to iron deficiency.
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Affiliation(s)
- Jean-François Jacques
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Alexandre Mercier
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Ariane Brault
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Thierry Mourer
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Simon Labbé
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- * E-mail:
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41
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Dhalleine T, Rouhier N, Couturier J. Putative roles of glutaredoxin-BolA holo-heterodimers in plants. PLANT SIGNALING & BEHAVIOR 2014; 9:e28564. [PMID: 24714563 PMCID: PMC4091568 DOI: 10.4161/psb.28564] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 03/17/2014] [Indexed: 05/26/2023]
Abstract
Several genomic analyses, high-throughput or targeted interaction studies including the purification of protein complexes indicated a physical and functional link between BolAs and monothiol glutaredoxins (Grxs) that is conserved both in prokaryotes and eukaryotes. In a recent work, we confirmed that several Arabidopsis protein couples, used as plant representatives, also physically interact. More interestingly, we determined that two BolA proteins, BolA2 and SufE1, contain a conserved cysteine that is sensitive to oxidizing treatments, unraveling a possible redox-control of BolA2 and SufE1 by monothiol glutaredoxins. By coexpressing physiological partners in E. coli, Grx-BolA heterodimers binding a labile, oxygen sensitive iron-sulfur cluster were isolated. Altogether, these results illustrate the existence of different modes of interaction between monothiol glutaredoxins and BolA proteins in plants and probably in other organisms. Incidentally, the function of each partner could be differentially modulated depending on the type of interaction.
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Affiliation(s)
- Tiphaine Dhalleine
- Université de Lorraine; Interactions Arbres - Microorganismes; UMR1136; Vandoeuvre-lès-Nancy, France
- INRA; Interactions Arbres - Microorganismes; UMR1136; Champenoux, France
| | - Nicolas Rouhier
- Université de Lorraine; Interactions Arbres - Microorganismes; UMR1136; Vandoeuvre-lès-Nancy, France
- INRA; Interactions Arbres - Microorganismes; UMR1136; Champenoux, France
| | - Jérémy Couturier
- Université de Lorraine; Interactions Arbres - Microorganismes; UMR1136; Vandoeuvre-lès-Nancy, France
- INRA; Interactions Arbres - Microorganismes; UMR1136; Champenoux, France
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42
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Molecular mechanism and structure of the Saccharomyces cerevisiae iron regulator Aft2. Proc Natl Acad Sci U S A 2014; 111:4043-8. [PMID: 24591629 DOI: 10.1073/pnas.1318869111] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The paralogous iron-responsive transcription factors Aft1 and Aft2 (activators of ferrous transport) regulate iron homeostasis in Saccharomyces cerevisiae by activating expression of iron-uptake and -transport genes when intracellular iron is low. We present the previously unidentified crystal structure of Aft2 bound to DNA that reveals the mechanism of DNA recognition via specific interactions of the iron-responsive element with a Zn(2+)-containing WRKY-GCM1 domain in Aft2. We also show that two Aft2 monomers bind a [2Fe-2S] cluster (or Fe(2+)) through a Cys-Asp-Cys motif, leading to dimerization of Aft2 and decreased DNA-binding affinity. Furthermore, we demonstrate that the [2Fe-2S]-bridged heterodimer formed between glutaredoxin-3 and the BolA-like protein Fe repressor of activation-2 transfers a [2Fe-2S] cluster to Aft2 that facilitates Aft2 dimerization. Previous in vivo findings strongly support the [2Fe-2S] cluster-induced dimerization model; however, given the available evidence, Fe(2+)-induced Aft2 dimerization cannot be completely ruled out as an alternative Aft2 inhibition mechanism. Taken together, these data provide insight into the molecular mechanism for iron-dependent transcriptional regulation of Aft2 and highlight the key role of Fe-S clusters as cellular iron signals.
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Stehling O, Wilbrecht C, Lill R. Mitochondrial iron-sulfur protein biogenesis and human disease. Biochimie 2014; 100:61-77. [PMID: 24462711 DOI: 10.1016/j.biochi.2014.01.010] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/13/2014] [Indexed: 12/29/2022]
Abstract
Work during the past 14 years has shown that mitochondria are the primary site for the biosynthesis of iron-sulfur (Fe/S) clusters. In fact, it is this process that renders mitochondria essential for viability of virtually all eukaryotes, because they participate in the synthesis of the Fe/S clusters of key nuclear and cytosolic proteins such as DNA polymerases, DNA helicases, and ABCE1 (Rli1), an ATPase involved in protein synthesis. As a consequence, mitochondrial function is crucial for nuclear DNA synthesis and repair, ribosomal protein synthesis, and numerous other extra-mitochondrial pathways including nucleotide metabolism and cellular iron regulation. Within mitochondria, the synthesis of Fe/S clusters and their insertion into apoproteins is assisted by 17 proteins forming the ISC (iron-sulfur cluster) assembly machinery. Biogenesis of mitochondrial Fe/S proteins can be dissected into three main steps: First, a Fe/S cluster is generated de novo on a scaffold protein. Second, the Fe/S cluster is dislocated from the scaffold and transiently bound to transfer proteins. Third, the latter components, together with specific ISC targeting factors insert the Fe/S cluster into client apoproteins. Disturbances of the first two steps impair the maturation of extra-mitochondrial Fe/S proteins and affect cellular and systemic iron homeostasis. In line with the essential function of mitochondria, genetic mutations in a number of ISC genes lead to severe neurological, hematological and metabolic diseases, often with a fatal outcome in early childhood. In this review we briefly summarize our current functional knowledge on the ISC assembly machinery, and we present a comprehensive overview of the various Fe/S protein assembly diseases.
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Affiliation(s)
- Oliver Stehling
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany
| | - Claudia Wilbrecht
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany; Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany; LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Str., 35043 Marburg, Germany.
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Couturier J, Wu HC, Dhalleine T, Pégeot H, Sudre D, Gualberto JM, Jacquot JP, Gaymard F, Vignols F, Rouhier N. Monothiol glutaredoxin-BolA interactions: redox control of Arabidopsis thaliana BolA2 and SufE1. MOLECULAR PLANT 2014; 7:187-205. [PMID: 24203231 DOI: 10.1093/mp/sst156] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A functional relationship between monothiol glutaredoxins and BolAs has been unraveled by genomic analyses and in several high-throughput studies. Phylogenetic analyses coupled to transient expression of green fluorescent protein (GFP) fusions indicated that, in addition to the sulfurtransferase SufE1, which contains a C-terminal BolA domain, three BolA isoforms exist in Arabidopsis thaliana, BolA1 being plastidial, BolA2 nucleo-cytoplasmic, and BolA4 dual-targeted to mitochondria and plastids. Binary yeast two-hybrid experiments demonstrated that all BolAs and SufE1, via its BolA domain, can interact with all monothiol glutaredoxins. Most interactions between protein couples of the same subcellular compartment have been confirmed by bimolecular fluorescence complementation. In vitro experiments indicated that monothiol glutaredoxins could regulate the redox state of BolA2 and SufE1, both proteins possessing a single conserved reactive cysteine. Indeed, a glutathionylated form of SufE1 lost its capacity to activate the cysteine desulfurase, Nfs2, but it is reactivated by plastidial glutaredoxins. Besides, a monomeric glutathionylated form and a dimeric disulfide-bridged form of BolA2 can be preferentially reduced by the nucleo-cytoplasmic GrxS17. These results indicate that the glutaredoxin-BolA interaction occurs in several subcellular compartments and suggest that a redox regulation mechanism, disconnected from their capacity to form iron-sulfur cluster-bridged heterodimers, may be physiologically relevant for BolA2 and SufE1.
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Affiliation(s)
- Jérémy Couturier
- a Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, F-54500 Vandoeuvre-lès-Nancy, France
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Hanschmann EM, Godoy JR, Berndt C, Hudemann C, Lillig CH. Thioredoxins, glutaredoxins, and peroxiredoxins--molecular mechanisms and health significance: from cofactors to antioxidants to redox signaling. Antioxid Redox Signal 2013; 19:1539-605. [PMID: 23397885 PMCID: PMC3797455 DOI: 10.1089/ars.2012.4599] [Citation(s) in RCA: 494] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 02/01/2013] [Accepted: 02/07/2013] [Indexed: 12/19/2022]
Abstract
Thioredoxins (Trxs), glutaredoxins (Grxs), and peroxiredoxins (Prxs) have been characterized as electron donors, guards of the intracellular redox state, and "antioxidants". Today, these redox catalysts are increasingly recognized for their specific role in redox signaling. The number of publications published on the functions of these proteins continues to increase exponentially. The field is experiencing an exciting transformation, from looking at a general redox homeostasis and the pathological oxidative stress model to realizing redox changes as a part of localized, rapid, specific, and reversible redox-regulated signaling events. This review summarizes the almost 50 years of research on these proteins, focusing primarily on data from vertebrates and mammals. The role of Trx fold proteins in redox signaling is discussed by looking at reaction mechanisms, reversible oxidative post-translational modifications of proteins, and characterized interaction partners. On the basis of this analysis, the specific regulatory functions are exemplified for the cellular processes of apoptosis, proliferation, and iron metabolism. The importance of Trxs, Grxs, and Prxs for human health is addressed in the second part of this review, that is, their potential impact and functions in different cell types, tissues, and various pathological conditions.
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Affiliation(s)
- Eva-Maria Hanschmann
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
| | - José Rodrigo Godoy
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Carsten Berndt
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Christoph Hudemann
- Institute of Laboratory Medicine, Molecular Diagnostics, Philipps University, Marburg, Germany
| | - Christopher Horst Lillig
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
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Zhang B, Bandyopadhyay S, Shakamuri P, Naik SG, Huynh BH, Couturier J, Rouhier N, Johnson MK. Monothiol glutaredoxins can bind linear [Fe3S4]+ and [Fe4S4]2+ clusters in addition to [Fe2S2]2+ clusters: spectroscopic characterization and functional implications. J Am Chem Soc 2013; 135:15153-64. [PMID: 24032439 DOI: 10.1021/ja407059n] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Saccharomyces cerevisiae mitochondrial glutaredoxin 5 (Grx5) is the archetypical member of a ubiquitous class of monothiol glutaredoxins with a strictly conserved CGFS active-site sequence that has been shown to function in biological [Fe2S2](2+) cluster trafficking. In this work, we show that recombinant S. cerevisiae Grx5 purified aerobically, after prolonged exposure of the cell-free extract to air or after anaerobic reconstitution in the presence of glutathione, predominantly contains a linear [Fe3S4](+) cluster. The excited-state electronic properties and ground-state electronic and vibrational properties of the linear [Fe3S4](+) cluster have been characterized using UV-vis absorption/CD/MCD, EPR, Mössbauer, and resonance Raman spectroscopies. The results reveal a rhombic S = 5/2 linear [Fe3S4](+) cluster with properties similar to those reported for synthetic linear [Fe3S4](+) clusters and the linear [Fe3S4](+) clusters in purple aconitase. Moreover, the results indicate that the Fe-S cluster content previously reported for many monothiol Grxs has been misinterpreted exclusively in terms of [Fe2S2](2+) clusters, rather than linear [Fe3S4](+) clusters or mixtures of linear [Fe3S4](+) and [Fe2S2](2+) clusters. In the absence of GSH, anaerobic reconstitution of Grx5 yields a dimeric form containing one [Fe4S4](2+) cluster that is competent for in vitro activation of apo-aconitase, via intact cluster transfer. The ligation of the linear [Fe3S4](+) and [Fe4S4](2+) clusters in Grx5 has been assessed by spectroscopic, mutational, and analytical studies. Potential roles for monothiol Grx5 in scavenging and recycling linear [Fe3S4](+) clusters released during protein unfolding under oxidative stress conditions and in maturation of [Fe4S4](2+) cluster-containing proteins are discussed in light of these results.
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Affiliation(s)
- Bo Zhang
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
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Gao H, Subramanian S, Couturier J, Naik SG, Kim SK, Leustek T, Knaff DB, Wu HC, Vignols F, Huynh BH, Rouhier N, Johnson MK. Arabidopsis thaliana Nfu2 accommodates [2Fe-2S] or [4Fe-4S] clusters and is competent for in vitro maturation of chloroplast [2Fe-2S] and [4Fe-4S] cluster-containing proteins. Biochemistry 2013; 52:6633-45. [PMID: 24032747 DOI: 10.1021/bi4007622] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nfu-type proteins are essential in the biogenesis of iron-sulfur (Fe-S) clusters in numerous organisms. A number of phenotypes including low levels of Fe-S cluster incorporation are associated with the deletion of the gene encoding a chloroplast-specific Nfu-type protein, Nfu2 from Arabidopsis thaliana (AtNfu2). Here, we report that recombinant AtNfu2 is able to assemble both [2Fe-2S] and [4Fe-4S] clusters. Analytical data and gel filtration studies support cluster/protein stoichiometries of one [2Fe-2S] cluster/homotetramer and one [4Fe-4S] cluster/homodimer. The combination of UV-visible absorption and circular dichroism and resonance Raman and Mössbauer spectroscopies has been employed to investigate the nature, properties, and transfer of the clusters assembled on Nfu2. The results are consistent with subunit-bridging [2Fe-2S](2+) and [4Fe-4S](2+) clusters coordinated by the cysteines in the conserved CXXC motif. The results also provided insight into the specificity of Nfu2 for the maturation of chloroplastic Fe-S proteins via intact, rapid, and quantitative cluster transfer. [2Fe-2S] cluster-bound Nfu2 is shown to be an effective [2Fe-2S](2+) cluster donor for glutaredoxin S16 but not glutaredoxin S14. Moreover, [4Fe-4S] cluster-bound Nfu2 is shown to be a very rapid and efficient [4Fe-4S](2+) cluster donor for adenosine 5'-phosphosulfate reductase (APR1), and yeast two-hybrid studies indicate that APR1 forms a complex with Nfu2 but not with Nfu1 and Nfu3, the two other chloroplastic Nfu proteins. This cluster transfer is likely to be physiologically relevant and is particularly significant for plant metabolism as APR1 catalyzes the second step in reductive sulfur assimilation, which ultimately results in the biosynthesis of cysteine, methionine, glutathione, and Fe-S clusters.
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Affiliation(s)
- Huanyao Gao
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia, 30602, United States
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Manta B, Pavan C, Sturlese M, Medeiros A, Crispo M, Berndt C, Krauth-Siegel RL, Bellanda M, Comini MA. Iron-sulfur cluster binding by mitochondrial monothiol glutaredoxin-1 of Trypanosoma brucei: molecular basis of iron-sulfur cluster coordination and relevance for parasite infectivity. Antioxid Redox Signal 2013; 19:665-82. [PMID: 23259530 PMCID: PMC3739951 DOI: 10.1089/ars.2012.4859] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AIMS Monothiol glutaredoxins (1-C-Grxs) are small proteins linked to the cellular iron and redox metabolism. Trypanosoma brucei brucei, model organism for human African trypanosomiasis, expresses three 1-C-Grxs. 1-C-Grx1 is a highly abundant mitochondrial protein capable to bind an iron-sulfur cluster (ISC) in vitro using glutathione (GSH) as cofactor. We here report on the functional and structural analysis of 1-C-Grx1 in relation to its ISC-binding properties. RESULTS An N-terminal extension unique to 1-C-Grx1 from trypanosomatids affects the oligomeric structure and the ISC-binding capacity of the protein. The active-site Cys104 is essential for ISC binding, and the parasite-specific glutathionylspermidine and trypanothione can replace GSH as the ligands of the ISC. Interestingly, trypanothione forms stable protein-free ISC species that in vitro are incorporated into the dithiol T. brucei 2-C-Grx1, but not 1-C-Grx1. Overexpression of the C104S mutant of 1-C-Grx1 impairs disease progression in a mouse model. The structure of the Grx-domain of 1-C-Grx1 was solved by nuclear magnetic resonance spectroscopy. Despite the fact that several residues--which in other 1-C-Grxs are involved in the noncovalent binding of GSH--are conserved, different physicochemical approaches did not reveal any specific interaction between 1-C-Grx1 and free thiol ligands. INNOVATION Parasite Grxs are able to coordinate an ISC formed with trypanothione, suggesting a new mechanism of ISC binding and a novel function for the parasite-specific dithiol. The first 3D structure and in vivo relevance of a 1-C-Grx from a pathogenic protozoan are reported. CONCLUSION T. brucei 1-C-Grx1 is indispensable for mammalian parasitism and utilizes a new mechanism for ISC binding.
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Affiliation(s)
- Bruno Manta
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
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Comini MA, Krauth-Siegel RL, Bellanda M. Mono- and dithiol glutaredoxins in the trypanothione-based redox metabolism of pathogenic trypanosomes. Antioxid Redox Signal 2013; 19:708-22. [PMID: 22978520 PMCID: PMC3739957 DOI: 10.1089/ars.2012.4932] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE Glutaredoxins are ubiquitous small thiol proteins of the thioredoxin-fold superfamily. Two major groups are distinguished based on their active sites: the dithiol (2-C-Grxs) and the monothiol (1-C-Grxs) glutaredoxins with a CXXC and a CXXS active site motif, respectively. Glutaredoxins are involved in cellular redox and/or iron sulfur metabolism. Usually their functions are closely linked to the glutathione system. Trypanosomatids, the causative agents of several tropical diseases, rely on trypanothione as principal low molecular mass thiol, and their glutaredoxins readily react with the unique bis(glutathionyl) spermidine conjugate. RECENT ADVANCES Two 2-C-Grxs and three 1-C-Grxs have been identified in pathogenic trypanosomatids. The 2-C-Grxs catalyze the reduction of glutathione disulfide by trypanothione and display reductase activity towards protein disulfides, as well as protein-glutathione mixed disulfides. In vitro, all three 1-C-Grxs as well as the cytosolic 2-C-Grx of Trypanosoma brucei can complex an iron-sulfur cluster. Recently the structure of the 1-C-Grx1 has been solved by NMR spectroscopy. The structure is very similar to those of other 1-C-Grxs, with some differences in the loop containing the conserved cis-Pro and the surface charge distribution. CRITICAL ISSUES Although four of the five trypanosomal glutaredoxins proved to coordinate an iron-sulfur cluster in vitro, the physiological role of the mitochondrial and cytosolic proteins, respectively, has only started to be unraveled. FUTURE DIRECTIONS The use of trypanothione by the glutaredoxins has established a novel role for this parasite-specific dithiol. Future work should reveal if these differences can be exploited for the development of novel antiparasitic drugs.
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Affiliation(s)
- Marcelo A Comini
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay.
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The Synechocystis PCC6803 MerA-like enzyme operates in the reduction of both mercury and uranium under the control of the glutaredoxin 1 enzyme. J Bacteriol 2013; 195:4138-45. [PMID: 23852862 DOI: 10.1128/jb.00272-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In a continuing effort to analyze the selectivity/redundancy of the three glutaredoxin (Grx) enzymes of the model cyanobacterium Synechocystis PCC6803, we have characterized an enzyme system that plays a crucial role in protection against two toxic metal pollutants, mercury and uranium. The present data show that Grx1 (Slr1562 in CyanoBase) selectively interacts with the presumptive mercuric reductase protein (Slr1849). This MerA enzyme plays a crucial role in cell defense against both mercuric and uranyl ions, in catalyzing their NADPH-driven reduction. Like MerA, Grx1 operates in cell protection against both mercury and uranium. The Grx1-MerA interaction requires cysteine 86 (C86) of Grx1 and C78 of MerA, which is critical for its reductase activity. MerA can be inhibited by glutathionylation and subsequently reactivated by Grx1, likely through deglutathionylation. The two Grx1 residues C31, which belongs to the redox active site (CX(2)C), and C86, which operates in MerA interactions, are both required for reactivation of MerA. These novel findings emphasize the role of glutaredoxins in tolerance to metal stress as well as the evolutionary conservation of the glutathionylation process, so far described mostly for eukaryotes.
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