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Antioxidant ability of glutaredoxins and their role in symbiotic nitrogen fixation in Rhizobium leguminosarum bv. viciae 3841. Appl Environ Microbiol 2021; 87:AEM.01956-20. [PMID: 33277272 PMCID: PMC7851698 DOI: 10.1128/aem.01956-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Glutaredoxins (Grx) are redoxin family proteins that reduce disulfides and mixed disulfides between glutathione and proteins. Rhizobium leguminosarum bv. Viciae 3841 contains three genes coding for glutaredoxins: RL4289 (grxA) codes for a dithiolic glutaredoxin, RL2615 (grxB) codes for a monothiol glutaredoxin, while RL4261 (grxC) codes for a glutaredoxin-like NrdH protein. We generated mutants interrupted in one, two, or three glutaredoxin genes. These mutants had no obvious differences in growth phenotypes from the wild type RL3841. However, while a mutant of grxC did not affect the antioxidant or symbiotic capacities of R. leguminosarum, grxA-derived or grxB mutants decreased antioxidant and nitrogen fixation capacities. Furthermore, grxA mutants were severely impaired in rhizosphere colonization, and formed smaller nodules with defects of bacteroid differentiation, whereas nodules induced by grxB mutants contained abnormally thick cortices and prematurely senescent bacteroids. The grx triple mutant had the greatest defect in antioxidant and symbiotic capacities of R. leguminosarum and quantitative proteomics revealed it had 56 up-regulated and 81 down-regulated proteins relative to wildtype. Of these proteins, twenty-eight are involved in transporter activity, twenty are related to stress response and virulence, and sixteen are involved in amino acid metabolism. Overall, R. leguminosarum glutaredoxins behave as antioxidant proteins mediating root nodule symbiosis.IMPORTANCE Glutaredoxin catalyzes glutathionylation/deglutathionylation reactions, protects SH-groups from oxidation and restores functionally active thiols. Three glutaredoxins exist in R. leguminosarum and their properties were investigated in free-living bacteria and during nitrogen-fixing symbiosis. All the glutaredoxins were necessary for oxidative stress defense. Dithiol GrxA affects nodulation and nitrogen fixation of bacteroids by altering deglutathionylation reactions, monothiol GrxB is involved in symbiotic nitrogen fixation by regulating Fe-S cluster biogenesis, and GrxC may participate in symbiosis by an unknown mechanism. Proteome analysis provides clues to explain the differences between the grx triple mutant and wild-type nodules.
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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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3
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Ramos-Alonso L, Romero AM, Martínez-Pastor MT, Puig S. Iron Regulatory Mechanisms in Saccharomyces cerevisiae. Front Microbiol 2020; 11:582830. [PMID: 33013818 PMCID: PMC7509046 DOI: 10.3389/fmicb.2020.582830] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
Iron is an essential micronutrient for all eukaryotic organisms because it participates as a redox cofactor in many cellular processes. However, excess iron can damage cells since it promotes the generation of reactive oxygen species. The budding yeast Saccharomyces cerevisiae has been used as a model organism to study the adaptation of eukaryotic cells to changes in iron availability. Upon iron deficiency, yeast utilizes two transcription factors, Aft1 and Aft2, to activate the expression of a set of genes known as the iron regulon, which are implicated in iron uptake, recycling and mobilization. Moreover, Aft1 and Aft2 activate the expression of Cth2, an mRNA-binding protein that limits the expression of genes encoding for iron-containing proteins or that participate in iron-using processes. Cth2 contributes to prioritize iron utilization in particular pathways over other highly iron-consuming and non-essential processes including mitochondrial respiration. Recent studies have revealed that iron deficiency also alters many other metabolic routes including amino acid and lipid synthesis, the mitochondrial retrograde response, transcription, translation and deoxyribonucleotide synthesis; and activates the DNA damage and general stress responses. At high iron levels, the yeast Yap5, Msn2, and Msn4 transcription factors activate the expression of a vacuolar iron importer called Ccc1, which is the most important high-iron protecting factor devoted to detoxify excess cytosolic iron that is stored into the vacuole for its mobilization upon scarcity. The complete sequencing and annotation of many yeast genomes is starting to unveil the diversity and evolution of the iron homeostasis network in this species.
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Affiliation(s)
- Lucía Ramos-Alonso
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | - Antonia María Romero
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | | | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
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4
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Ror S, Panwar SL. Sef1-Regulated Iron Regulon Responds to Mitochondria-Dependent Iron-Sulfur Cluster Biosynthesis in Candida albicans. Front Microbiol 2019; 10:1528. [PMID: 31354649 PMCID: PMC6630100 DOI: 10.3389/fmicb.2019.01528] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/18/2019] [Indexed: 11/13/2022] Open
Abstract
Iron homeostasis mechanisms allow the prime commensal-pathogen Candida albicans to cope with the profound shift in iron levels in the mammalian host. The regulators, Sef1 and Sfu1 influence activation and repression of genes required for iron uptake and acquisition by inducing the expression of iron regulon genes in iron-deplete conditions and inactivating them in iron-replete condition. Our study for the first time shows that C. albicans coordinates the activation of the iron regulon with the mitochondrial use of iron for Fe–S cluster biosynthesis, a cellular process that is connected to cellular iron metabolism. We took advantage of a mutant defective in mitochondrial biogenesis (fzo1Δ/Δ) to assess the aforesaid link as this mutant exhibited sustained expression of the Sef1 iron regulon, signifying an iron-starved state in the mutant. Our analysis demonstrates that mitochondrion is pivotal for regulation of Fe–S cluster synthesis such that the disruption of this cellular process in fzo1Δ/Δ cells lead to excessive mitochondrial iron accumulation and reduced activity of the Fe–S cluster-containing enzyme aconitase. Sef1 responds to defective Fe–S cluster synthesis by regulated changes in its subcellular localization; it was retained in the nucleus resulting in the induced expression of the iron regulon. We predict that the mitochondrial Fe–S assembly generates a molecule that is critical for ensuring iron-responsive transcriptional activation of the Sef1 regulon. All told, our data marks Fe–S biogenesis as a mechanism that meshes cellular iron procurement with mitochondrial iron metabolism resulting in regulating the Sef1 regulon in C. albicans.
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Affiliation(s)
- Shivani Ror
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sneh Lata Panwar
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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5
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Romero AM, Jordá T, Rozès N, Martínez-Pastor MT, Puig S. Regulation of yeast fatty acid desaturase in response to iron deficiency. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:657-668. [PMID: 29627385 DOI: 10.1016/j.bbalip.2018.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/12/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
Abstract
Unsaturated fatty acids (UFA) are essential components of phospholipids that greatly contribute to the biophysical properties of cellular membranes. Biosynthesis of UFAs relies on a conserved family of iron-dependent fatty acid desaturases, whose representative in the model yeast Saccharomyces cerevisiae is Ole1. OLE1 expression is tightly regulated to adapt UFA biosynthesis and lipid bilayer properties to changes in temperature, and in UFA or oxygen availability. Despite iron deficiency being the most extended nutritional disorder worldwide, very little is known about the mechanisms and the biological relevance of fatty acid desaturases regulation in response to iron starvation. In this report, we show that endoplasmic reticulum-anchored transcription factor Mga2 activates OLE1 transcription in response to nutritional and genetic iron deficiencies. Cells lacking MGA2 display low UFA levels and do not grow under iron-limited conditions, unless UFAs are supplemented or OLE1 is overexpressed. The proteasome, E3 ubiquitin ligase Rsp5 and the Cdc48Npl4/Ufd1 complex are required for OLE1 activation during iron depletion. Interestingly, Mga2 also activates the transcription of its own mRNA in response to iron deficiency, hypoxia, low temperature and low UFAs. MGA2 up-regulation contributes to increase OLE1 expression in these situations. These results reveal the mechanism of OLE1 regulation when iron is scarce and identify the MGA2 auto-regulation as a potential activation strategy in multiple stresses.
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Affiliation(s)
- Antonia María Romero
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Tania Jordá
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Nicolas Rozès
- Departament de Bioquímica i Biotecnología, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Spain
| | | | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain.
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6
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Inokuma K, Iwamoto R, Bamba T, Hasunuma T, Kondo A. Improvement of Xylose Fermentation Ability under Heat and Acid Co-Stress in Saccharomyces cerevisiae Using Genome Shuffling Technique. Front Bioeng Biotechnol 2017; 5:81. [PMID: 29326929 PMCID: PMC5742482 DOI: 10.3389/fbioe.2017.00081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/08/2017] [Indexed: 12/26/2022] Open
Abstract
Xylose-assimilating yeasts with tolerance to both fermentation inhibitors (such as weak organic acids) and high temperature are required for cost-effective simultaneous saccharification and cofermentation (SSCF) of lignocellulosic materials. Here, we demonstrate the construction of a novel xylose-utilizing Saccharomyces cerevisiae strain with improved fermentation ability under heat and acid co-stress using the drug resistance marker-aided genome shuffling technique. The mutagenized genome pools derived from xylose-utilizing diploid yeasts with thermotolerance or acid tolerance were shuffled by sporulation and mating. The shuffled strains were then subjected to screening under co-stress conditions of heat and acids, and the hybrid strain Hyb-8 was isolated. The hybrid strain displayed enhanced xylose fermentation ability in comparison to both parental strains under co-stress conditions of heat and acids. Hyb-8 consumed 33.1 ± 0.6 g/L xylose and produced 11.1 ± 0.4 g/L ethanol after 72 h of fermentation at 38°C with 20 mM acetic acid and 15 mM formic acid. We also performed transcriptomic analysis of the hybrid strain and its parental strains to screen for key genes for multiple stress tolerances. We found that 13 genes, including 5 associated with cellular transition metal ion homeostasis, were significantly upregulated in Hyb-8 compared to levels in both parental strains under co-stress conditions. The hybrid strain Hyb-8 has strong potential for cost-effective SSCF of lignocellulosic materials. Moreover, the transcriptome data gathered in this study will be useful for understanding the mechanisms of multiple tolerance to high temperature and acids in yeast and facilitate the development of robust yeast strains for SSCF.
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Affiliation(s)
- Kentaro Inokuma
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Ryo Iwamoto
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Takahiro Bamba
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan.,Biomass Engineering Program, RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, Japan
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7
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Tripathi SK, Xu T, Feng Q, Avula B, Shi X, Pan X, Mask MM, Baerson SR, Jacob MR, Ravu RR, Khan SI, Li XC, Khan IA, Clark AM, Agarwal AK. Two plant-derived aporphinoid alkaloids exert their antifungal activity by disrupting mitochondrial iron-sulfur cluster biosynthesis. J Biol Chem 2017; 292:16578-16593. [PMID: 28821607 PMCID: PMC5633121 DOI: 10.1074/jbc.m117.781773] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/15/2017] [Indexed: 11/06/2022] Open
Abstract
Eupolauridine and liriodenine are plant-derived aporphinoid alkaloids that exhibit potent inhibitory activity against the opportunistic fungal pathogens Candida albicans and Cryptococcus neoformans However, the molecular mechanism of this antifungal activity is unknown. In this study, we show that eupolauridine 9591 (E9591), a synthetic analog of eupolauridine, and liriodenine methiodide (LMT), a methiodide salt of liriodenine, mediate their antifungal activities by disrupting mitochondrial iron-sulfur (Fe-S) cluster synthesis. Several lines of evidence supported this conclusion. First, both E9591 and LMT elicited a transcriptional response indicative of iron imbalance, causing the induction of genes that are required for iron uptake and for the maintenance of cellular iron homeostasis. Second, a genome-wide fitness profile analysis showed that yeast mutants with deletions in iron homeostasis-related genes were hypersensitive to E9591 and LMT. Third, treatment of wild-type yeast cells with E9591 or LMT generated cellular defects that mimicked deficiencies in mitochondrial Fe-S cluster synthesis including an increase in mitochondrial iron levels, a decrease in the activities of Fe-S cluster enzymes, a decrease in respiratory function, and an increase in oxidative stress. Collectively, our results demonstrate that E9591 and LMT perturb mitochondrial Fe-S cluster biosynthesis; thus, these two compounds target a cellular pathway that is distinct from the pathways commonly targeted by clinically used antifungal drugs. Therefore, the identification of this pathway as a target for antifungal compounds has potential applications in the development of new antifungal therapies.
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Affiliation(s)
| | - Tao Xu
- From the National Center for Natural Products Research
| | - Qin Feng
- From the National Center for Natural Products Research
| | | | - Xiaomin Shi
- the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, and
| | - Xuewen Pan
- the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, and
| | - Melanie M Mask
- the United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit, University, Mississippi 38677
| | - Scott R Baerson
- the United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit, University, Mississippi 38677
| | | | | | - Shabana I Khan
- From the National Center for Natural Products Research
- the Divisions of Pharmacognosy and
| | - Xing-Cong Li
- From the National Center for Natural Products Research
- the Divisions of Pharmacognosy and
| | - Ikhlas A Khan
- From the National Center for Natural Products Research
- the Divisions of Pharmacognosy and
| | - Alice M Clark
- From the National Center for Natural Products Research
- the Divisions of Pharmacognosy and
| | - Ameeta K Agarwal
- From the National Center for Natural Products Research,
- Pharmacology, Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, University, Mississippi 38677
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8
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Central roles of iron in the regulation of oxidative stress in the yeast Saccharomyces cerevisiae. Curr Genet 2017; 63:895-907. [DOI: 10.1007/s00294-017-0689-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/24/2017] [Accepted: 02/26/2017] [Indexed: 12/21/2022]
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9
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de Carvalho MDC, De Mesquita JF, Eleutherio ECA. In Vivo Characterization of I91T Sod2 Polymorphism of Saccharomyces cerevisiae. J Cell Biochem 2017; 118:1078-1086. [DOI: 10.1002/jcb.25720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/30/2016] [Indexed: 11/09/2022]
Affiliation(s)
| | - Joelma Freire De Mesquita
- Department of Genetics and Molecular Biology; Federal University of the State of Rio de Janeiro (UNIRIO); Rio de Janeiro 22290-240 Brazil
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10
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The Phenotypic Plasticity of Duplicated Genes in Saccharomyces cerevisiae and the Origin of Adaptations. G3-GENES GENOMES GENETICS 2017; 7:63-75. [PMID: 27799339 PMCID: PMC5217124 DOI: 10.1534/g3.116.035329] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gene and genome duplication are the major sources of biological innovations in plants and animals. Functional and transcriptional divergence between the copies after gene duplication has been considered the main driver of innovations . However, here we show that increased phenotypic plasticity after duplication plays a more major role than thought before in the origin of adaptations. We perform an exhaustive analysis of the transcriptional alterations of duplicated genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with five different environmental stresses. Analysis of the transcriptomes of yeast shows that gene duplication increases the transcriptional response to environmental changes, with duplicated genes exhibiting signatures of adaptive transcriptional patterns in response to stress. The mechanism of duplication matters, with whole-genome duplicates being more transcriptionally altered than small-scale duplicates. The predominant transcriptional pattern follows the classic theory of evolution by gene duplication; with one gene copy remaining unaltered under stress, while its sister copy presents large transcriptional plasticity and a prominent role in adaptation. Moreover, we find additional transcriptional profiles that are suggestive of neo- and subfunctionalization of duplicate gene copies. These patterns are strongly correlated with the functional dependencies and sequence divergence profiles of gene copies. We show that, unlike singletons, duplicates respond more specifically to stress, supporting the role of natural selection in the transcriptional plasticity of duplicates. Our results reveal the underlying transcriptional complexity of duplicated genes and its role in the origin of adaptations.
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11
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Frey AG, Palenchar DJ, Wildemann JD, Philpott CC. A Glutaredoxin·BolA Complex Serves as an Iron-Sulfur Cluster Chaperone for the Cytosolic Cluster Assembly Machinery. J Biol Chem 2016; 291:22344-22356. [PMID: 27519415 DOI: 10.1074/jbc.m116.744946] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/11/2016] [Indexed: 11/06/2022] Open
Abstract
Cells contain hundreds of proteins that require iron cofactors for activity. Iron cofactors are synthesized in the cell, but the pathways involved in distributing heme, iron-sulfur clusters, and ferrous/ferric ions to apoproteins remain incompletely defined. In particular, cytosolic monothiol glutaredoxins and BolA-like proteins have been identified as [2Fe-2S]-coordinating complexes in vitro and iron-regulatory proteins in fungi, but it is not clear how these proteins function in mammalian systems or how this complex might affect Fe-S proteins or the cytosolic Fe-S assembly machinery. To explore these questions, we use quantitative immunoprecipitation and live cell proximity-dependent biotinylation to monitor interactions between Glrx3, BolA2, and components of the cytosolic iron-sulfur cluster assembly system. We characterize cytosolic Glrx3·BolA2 as a [2Fe-2S] chaperone complex in human cells. Unlike complexes formed by fungal orthologs, human Glrx3-BolA2 interaction required the coordination of Fe-S clusters, whereas Glrx3 homodimer formation did not. Cellular Glrx3·BolA2 complexes increased 6-8-fold in response to increasing iron, forming a rapidly expandable pool of Fe-S clusters. Fe-S coordination by Glrx3·BolA2 did not depend on Ciapin1 or Ciao1, proteins that bind Glrx3 and are involved in cytosolic Fe-S cluster assembly and distribution. Instead, Glrx3 and BolA2 bound and facilitated Fe-S incorporation into Ciapin1, a [2Fe-2S] protein functioning early in the cytosolic Fe-S assembly pathway. Thus, Glrx3·BolA is a [2Fe-2S] chaperone complex capable of transferring [2Fe-2S] clusters to apoproteins in human cells.
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Affiliation(s)
- Avery G Frey
- From the Genetics and Metabolism Section, Liver Diseases Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Daniel J Palenchar
- From the Genetics and Metabolism Section, Liver Diseases Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892 and
| | | | - Caroline C Philpott
- From the Genetics and Metabolism Section, Liver Diseases Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892 and
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12
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Garrido-Godino AI, García-López MC, García-Martínez J, Pelechano V, Medina DA, Pérez-Ortín JE, Navarro F. Rpb1 foot mutations demonstrate a major role of Rpb4 in mRNA stability during stress situations in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:731-43. [PMID: 27001033 DOI: 10.1016/j.bbagrm.2016.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 01/22/2023]
Abstract
The RPB1 mutants in the foot region of RNA polymerase II affect the assembly of the complex by altering the correct association of both the Rpb6 and the Rpb4/7 dimer. Assembly defects alter both transcriptional activity as well as the amount of enzyme associated with genes. Here, we show that the global transcriptional analysis of foot mutants reveals the activation of an environmental stress response (ESR), which occurs at a permissive temperature under optimal growth conditions. Our data indicate that the ESR that occurs in foot mutants depends mostly on a global post-transcriptional regulation mechanism which, in turn, depends on Rpb4-mRNA imprinting. Under optimal growth conditions, we propose that Rpb4 serves as a key to globally modulate mRNA stability as well as to coordinate transcription and decay. Overall, our results imply that post-transcriptional regulation plays a major role in controlling the ESR at both the transcription and mRNA decay levels.
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Affiliation(s)
- A I Garrido-Godino
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Paraje de las Lagunillas, s/n, 23071 Jaén, Spain
| | - M C García-López
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Paraje de las Lagunillas, s/n, 23071 Jaén, Spain
| | - J García-Martínez
- Departamento de Genética, Facultad de Biológicas, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain; ERI Biotecmed, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain
| | - V Pelechano
- European Molecular Biology Laboratories (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - D A Medina
- ERI Biotecmed, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain; Departamento de Bioquímica y Biología Molecular, Facultad de Biológicas, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain
| | - J E Pérez-Ortín
- ERI Biotecmed, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain; Departamento de Bioquímica y Biología Molecular, Facultad de Biológicas, Universitat de València, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain.
| | - F Navarro
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Paraje de las Lagunillas, s/n, 23071 Jaén, Spain.
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13
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Compartmentalization of iron between mitochondria and the cytosol and its regulation. Eur J Cell Biol 2015; 94:292-308. [DOI: 10.1016/j.ejcb.2015.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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14
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The production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug. Antimicrob Agents Chemother 2014; 58:6627-38. [PMID: 25155595 DOI: 10.1128/aac.03570-14] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal.
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15
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Abstract
All living organisms require nutrient minerals for growth and have developed mechanisms to acquire, utilize, and store nutrient minerals effectively. In the aqueous cellular environment, these elements exist as charged ions that, together with protons and hydroxide ions, facilitate biochemical reactions and establish the electrochemical gradients across membranes that drive cellular processes such as transport and ATP synthesis. Metal ions serve as essential enzyme cofactors and perform both structural and signaling roles within cells. However, because these ions can also be toxic, cells have developed sophisticated homeostatic mechanisms to regulate their levels and avoid toxicity. Studies in Saccharomyces cerevisiae have characterized many of the gene products and processes responsible for acquiring, utilizing, storing, and regulating levels of these ions. Findings in this model organism have often allowed the corresponding machinery in humans to be identified and have provided insights into diseases that result from defects in ion homeostasis. This review summarizes our current understanding of how cation balance is achieved and modulated in baker's yeast. Control of intracellular pH is discussed, as well as uptake, storage, and efflux mechanisms for the alkali metal cations, Na(+) and K(+), the divalent cations, Ca(2+) and Mg(2+), and the trace metal ions, Fe(2+), Zn(2+), Cu(2+), and Mn(2+). Signal transduction pathways that are regulated by pH and Ca(2+) are reviewed, as well as the mechanisms that allow cells to maintain appropriate intracellular cation concentrations when challenged by extreme conditions, i.e., either limited availability or toxic levels in the environment.
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Thiol redox sensitivity of two key enzymes of heme biosynthesis and pentose phosphate pathways: uroporphyrinogen decarboxylase and transketolase. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:932472. [PMID: 23970950 PMCID: PMC3730168 DOI: 10.1155/2013/932472] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/10/2013] [Accepted: 06/19/2013] [Indexed: 12/22/2022]
Abstract
Uroporphyrinogen decarboxylase (Hem12p) and transketolase (Tkl1p) are key mediators of two critical processes within the cell, heme biosynthesis, and the nonoxidative part of the pentose phosphate pathway (PPP). The redox properties of both Hem12p and Tkl1p from Saccharomyces cerevisiae were investigated using proteomic techniques (SRM and label-free quantification) and biochemical assays in cell extracts and in vitro with recombinant proteins. The in vivo analysis revealed an increase in oxidized Cys-peptides in the absence of Grx2p, and also after treatment with H2O2 in the case of Tkl1p, without corresponding changes in total protein, demonstrating a true redox response. Out of three detectable Cys residues in Hem12p, only the conserved residue Cys52 could be modified by glutathione and efficiently deglutathionylated by Grx2p, suggesting a possible redox control mechanism for heme biosynthesis. On the other hand, Tkl1p activity was sensitive to thiol redox modification and although Cys622 could be glutathionylated to a limited extent, it was not a natural substrate of Grx2p. The human orthologues of both enzymes have been involved in certain cancers and possess Cys residues equivalent to those identified as redox sensitive in yeast. The possible implication for redox regulation in the context of tumour progression is put forward.
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Sánchez-Riego AM, López-Maury L, Florencio FJ. Glutaredoxins are essential for stress adaptation in the cyanobacterium Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2013; 4:428. [PMID: 24204369 PMCID: PMC3816324 DOI: 10.3389/fpls.2013.00428] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/10/2013] [Indexed: 05/10/2023]
Abstract
Glutaredoxins are small redox proteins able to reduce disulfides and mixed disulfides between GSH and proteins. Synechocystis sp. PCC 6803 contains three genes coding for glutaredoxins: ssr2061 (grxA) and slr1562 (grxB) code for dithiolic glutaredoxins while slr1846 (grxC) codes for a monothiolic glutaredoxin. We have analyzed the expression of these glutaredoxins in response to different stresses, such as high light, H2O2 and heat shock. Analysis of the mRNA levels showed that grxA is only induced by heat while grxC is repressed by heat shock and is induced by high light and H2O2. In contrast, grxB expression was maintained almost constant under all conditions. Analysis of GrxA and GrxC protein levels by western blot showed that GrxA increases in response to high light, heat or H2O2 while GrxC is only induced by high light and H2O2, in accordance with its mRNA levels. In addition, we have also generated mutants that have interrupted one, two, or three glutaredoxin genes. These mutants were viable and did not show any different phenotype from the WT under standard growth conditions. Nevertheless, analysis of these mutants under several stress conditions revealed that single grxA mutants grow slower after H2O2, heat and high light treatments, while mutants in grxB are indistinguishable from WT. grxC mutants were hypersensitive to treatments with H2O2, heat, high light and metals. A double grxAgrxC mutant was found to be even more sensitive to H2O2 than each corresponding single mutants. Surprisingly a mutation in grxB suppressed totally or partially the phenotypes of grxA and grxC mutants except the H2O2 sensitivity of the grxC mutant. This suggests that grxA and grxC participate in independent pathways while grxA and grxB participate in a common pathway for H2O2 resistance. The data presented here show that glutaredoxins are essential for stress adaptation in cyanobacteria, although their targets and mechanism of action remain unidentified.
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Affiliation(s)
| | | | - Francisco J. Florencio
- *Correspondence: Francisco J. Florencio, Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Av Americo Vespucio 49, E 41092 Seville, Spain e-mail:
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Lill R, Hoffmann B, Molik S, Pierik AJ, Rietzschel N, Stehling O, Uzarska MA, Webert H, Wilbrecht C, Mühlenhoff U. The role of mitochondria in cellular iron-sulfur protein biogenesis and iron metabolism. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:1491-508. [PMID: 22609301 DOI: 10.1016/j.bbamcr.2012.05.009] [Citation(s) in RCA: 364] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 12/21/2022]
Abstract
Mitochondria play a key role in iron metabolism in that they synthesize heme, assemble iron-sulfur (Fe/S) proteins, and participate in cellular iron regulation. Here, we review the latter two topics and their intimate connection. The mitochondrial Fe/S cluster (ISC) assembly machinery consists of 17 proteins that operate in three major steps of the maturation process. First, the cysteine desulfurase complex Nfs1-Isd11 as the sulfur donor cooperates with ferredoxin-ferredoxin reductase acting as an electron transfer chain, and frataxin to synthesize an [2Fe-2S] cluster on the scaffold protein Isu1. Second, the cluster is released from Isu1 and transferred toward apoproteins with the help of a dedicated Hsp70 chaperone system and the glutaredoxin Grx5. Finally, various specialized ISC components assist in the generation of [4Fe-4S] clusters and cluster insertion into specific target apoproteins. Functional defects of the core ISC assembly machinery are signaled to cytosolic or nuclear iron regulatory systems resulting in increased cellular iron acquisition and mitochondrial iron accumulation. In fungi, regulation is achieved by iron-responsive transcription factors controlling the expression of genes involved in iron uptake and intracellular distribution. They are assisted by cytosolic multidomain glutaredoxins which use a bound Fe/S cluster as iron sensor and additionally perform an essential role in intracellular iron delivery to target metalloproteins. In mammalian cells, the iron regulatory proteins IRP1, an Fe/S protein, and IRP2 act in a post-transcriptional fashion to adjust the cellular needs for iron. Thus, Fe/S protein biogenesis and cellular iron metabolism are tightly linked to coordinate iron supply and utilization. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Str. 6, 35033 Marburg, Germany.
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19
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Li L, Miao R, Bertram S, Jia X, Ward DM, Kaplan J. A role for iron-sulfur clusters in the regulation of transcription factor Yap5-dependent high iron transcriptional responses in yeast. J Biol Chem 2012; 287:35709-35721. [PMID: 22915593 DOI: 10.1074/jbc.m112.395533] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Yeast respond to increased cytosolic iron by activating the transcription factor Yap5 increasing transcription of CCC1, which encodes a vacuolar iron importer. Using a genetic screen to identify genes involved in Yap5 iron sensing, we discovered that a mutation in SSQ1, which encodes a mitochondrial chaperone involved in iron-sulfur cluster synthesis, prevented expression of Yap5 target genes. We demonstrated that mutation or reduced expression of other genes involved in mitochondrial iron-sulfur cluster synthesis (YFH1, ISU1) prevented induction of the Yap5 response. We took advantage of the iron-dependent catalytic activity of Pseudaminobacter salicylatoxidans gentisate 1,2-dioxygenase expressed in yeast to measure changes in cytosolic iron. We determined that reductions in iron-sulfur cluster synthesis did not affect the activity of cytosolic gentisate 1,2-dioxygenase. We show that loss of activity of the cytosolic iron-sulfur cluster assembly complex proteins or deletion of cytosolic glutaredoxins did not reduce expression of Yap5 target genes. These results suggest that the high iron transcriptional response, as well as the low iron transcriptional response, senses iron-sulfur clusters.
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Affiliation(s)
- Liangtao Li
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Ren Miao
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Sophie Bertram
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Xuan Jia
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Diane M Ward
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Jerry Kaplan
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132.
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Proteomic analysis of Frankliniella occidentalis and differentially expressed proteins in response to tomato spotted wilt virus infection. J Virol 2012; 86:8793-809. [PMID: 22696645 DOI: 10.1128/jvi.00285-12] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tomato spotted wilt virus (TSWV) is transmitted by Frankliniella occidentalis in a persistent propagative manner. Despite the extensive replication of TSWV in midgut and salivary glands, there is little to no pathogenic effect on F. occidentalis. We hypothesize that the first-instar larva (L1) of F. occidentalis mounts a response to TSWV that protects it from pathogenic effects caused by virus infection and replication in various insect tissues. A partial thrips transcriptome was generated using 454-Titanium sequencing of cDNA generated from F. occidentalis exposed to TSWV. Using these sequences, the L1 thrips proteome that resolved on a two-dimensional gel was characterized. Forty-seven percent of the resolved protein spots were identified using the thrips transcriptome. Real-time quantitative reverse transcriptase PCR (RT-PCR) analysis of virus titer in L1 thrips revealed a significant increase in the normalized abundance of TSWV nucleocapsid RNA from 2 to 21 h after a 3-h acquisition access period on virus-infected plant tissue, indicative of infection and accumulation of virus. We compared the proteomes of infected and noninfected L1s to identify proteins that display differential abundances in response to virus. Using four biological replicates, 26 spots containing 37 proteins were significantly altered in response to TSWV. Gene ontology assignments for 32 of these proteins revealed biological roles associated with the infection cycle of other plant- and animal-infecting viruses and antiviral defense responses. Our findings support the hypothesis that L1 thrips display a complex reaction to TSWV infection and provide new insights toward unraveling the molecular basis of this interaction.
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Phylogenetic origin and transcriptional regulation at the post-diauxic phase of SPI1, in Saccharomyces cerevisiae. Cell Mol Biol Lett 2012; 17:393-407. [PMID: 22610976 PMCID: PMC6275683 DOI: 10.2478/s11658-012-0017-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 05/11/2012] [Indexed: 11/22/2022] Open
Abstract
The gene SPI1, of Saccharomyces cerevisiae, encodes a cell wall protein that is induced in several stress conditions, particularly in the postdiauxic and stationary phases of growth. It has a paralogue, SED1, which shows some common features in expression regulation and in the null mutant phenotype. In this work we have identified homologues in other species of yeasts and filamentous fungi, and we have also elucidated some aspects of the origin of SPI1, by duplication and diversification of SED1. In terms of regulation, we have found that the expression in the post-diauxic phase is regulated by genes related to the PKA pathway and stress response (MSN2/4, YAK1, POP2, SOK2, PHD1, and PHO84) and by genes involved in the PKC pathway (WSC2, PKC1, and MPK1).
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Riondet C, Desouris JP, Montoya JG, Chartier Y, Meyer Y, Reichheld JP. A dicotyledon-specific glutaredoxin GRXC1 family with dimer-dependent redox regulation is functionally redundant with GRXC2. PLANT, CELL & ENVIRONMENT 2012; 35:360-73. [PMID: 21767278 DOI: 10.1111/j.1365-3040.2011.02355.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The major known function of glutaredoxins (Grxs) is to reduce disulphide bridges. Recently, some have also been shown to interact with iron-sulphur clusters. These can be classified in two subgroups: class II Grx are found in all living organisms and are implicated in assembly of iron-sulphur clusters, while class I Grx are represented by only two members known to form a holodimer structure containing a cluster in vitro, but with an unknown function different from class II. Here, we report that in eukaryotic plants, GRXC1 (class I) orthologs are exclusively present in dicotyledonous plants, suggesting a specific function. Indeed, in Arabidopsis thaliana, reducing activity of recombinant GRXC1 is regulated by redox-dependent stability of the cluster. In planta, GRXC1 has been found predominantly in a holodimeric form, indicating the presence of the cluster in vivo. This suggests that GRXC1 acts as a redox sensor, reducing downstream pathways under oxidative conditions. GRXC2, the closest homolog of GRXC1, is unable to form a cluster in vitro. Knock-out mutants in grxc1 or grxc2 are aphenotypic, but the double mutant produces a lethal phenotype at an early stage after pollinization, suggesting that GRXC1 and GRXC2 share redundant and vital functions.
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Affiliation(s)
- Christophe Riondet
- Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS-UPVD, 58 Avenue de Villeneuve - Bat T, 66860 Perpignan Cedex, France.
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23
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Assembly Factors of Human Mitochondrial Respiratory Chain Complexes: Physiology and Pathophysiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:65-106. [DOI: 10.1007/978-1-4614-3573-0_4] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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24
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Castells‐Roca L, Mühlenhoff U, Lill R, Herrero E, Bellí G. The oxidative stress response in yeast cells involves changes in the stability of Aft1 regulon mRNAs. Mol Microbiol 2011; 81:232-48. [DOI: 10.1111/j.1365-2958.2011.07689.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laia Castells‐Roca
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Montserrat Roig 2, 25008‐Lleida, Spain
| | - Ulrich Mühlenhoff
- Institut für Zytobiologie und Zytopathologie, Philipps‐Universität Marburg, 35032 Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps‐Universität Marburg, 35032 Marburg, Germany
| | - Enrique Herrero
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Montserrat Roig 2, 25008‐Lleida, Spain
| | - Gemma Bellí
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Montserrat Roig 2, 25008‐Lleida, Spain
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25
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Murray DB, Haynes K, Tomita M. Redox regulation in respiring Saccharomyces cerevisiae. Biochim Biophys Acta Gen Subj 2011; 1810:945-58. [PMID: 21549177 DOI: 10.1016/j.bbagen.2011.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 03/16/2011] [Accepted: 04/17/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND In biological systems, redox reactions are central to most cellular processes and the redox potential of the intracellular compartment dictates whether a particular reaction can or cannot occur. Indeed the widespread use of redox reactions in biological systems makes their detailed description outside the scope of one review. SCOPE OF THE REVIEW Here we will focus on how system-wide redox changes can alter the reaction and transcriptional landscape of Saccharomyces cerevisiae. To understand this we explore the major determinants of cellular redox potential, how these are sensed by the cell and the dynamic responses elicited. MAJOR CONCLUSIONS Redox regulation is a large and complex system that has the potential to rapidly and globally alter both the reaction and transcription landscapes. Although we have a basic understanding of many of the sub-systems and a partial understanding of the transcriptional control, we are far from understanding how these systems integrate to produce coherent responses. We argue that this non-linear system self-organises, and that the output in many cases is temperature-compensated oscillations that may temporally partition incompatible reactions in vivo. GENERAL SIGNIFICANCE Redox biochemistry impinges on most of cellular processes and has been shown to underpin ageing and many human diseases. Integrating the complexity of redox signalling and regulation is perhaps one of the most challenging areas of biology. This article is part of a Special Issue entitled Systems Biology of Microorganisms.
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Affiliation(s)
- Douglas B Murray
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.
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26
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Hernández-Martínez P, Navarro-Cerrillo G, Caccia S, de Maagd RA, Moar WJ, Ferré J, Escriche B, Herrero S. Constitutive activation of the midgut response to Bacillus thuringiensis in Bt-resistant Spodoptera exigua. PLoS One 2010; 5:e12795. [PMID: 20862260 PMCID: PMC2941469 DOI: 10.1371/journal.pone.0012795] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 08/19/2010] [Indexed: 11/19/2022] Open
Abstract
Bacillus thuringiensis is the most effective microbial control agent for controlling numerous species from different insect orders. The main threat for the long term use of B. thuringiensis in pest control is the ability of insects to develop resistance. Thus, the identification of insect genes involved in conferring resistance is of paramount importance. A colony of Spodoptera exigua (Lepidoptera: Noctuidae) was selected for 15 years in the laboratory for resistance to Xentari™, a B. thuringiensis-based insecticide, reaching a final resistance level of greater than 1,000-fold. Around 600 midgut ESTs were analyzed by DNA-macroarray in order to find differences in midgut gene expression between susceptible and resistant insects. Among the differentially expressed genes, repat and arylphorin were identified and their increased expression was correlated with B. thuringiensis resistance. We also found overlap among genes that were constitutively over-expressed in resistant insects with genes that were up-regulated in susceptible insects after exposure to Xentari™, suggesting a permanent activation of the response to Xentari™ in resistant insects. Increased aminopeptidase activity in the lumen of resistant insects in the absence of exposure to Xentari™ corroborated the hypothesis of permanent activation of response genes. Increase in midgut proliferation has been proposed as a mechanism of response to pathogens in the adult from several insect species. Analysis of S. exigua larvae revealed that midgut proliferation was neither increased in resistant insects nor induced by exposure of susceptible larvae to Xentari™, suggesting that mechanisms other than midgut proliferation are involved in the response to B. thuringiensis by S. exigua larvae.
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Affiliation(s)
| | | | - Silvia Caccia
- Department of Genetics, Universitat de València, Burjassot, Spain
| | - Ruud A. de Maagd
- Plant Research International B.V., Wageningen University and Research Centre, Wageningen, The Netherlands
| | - William J. Moar
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Juan Ferré
- Department of Genetics, Universitat de València, Burjassot, Spain
| | | | - Salvador Herrero
- Department of Genetics, Universitat de València, Burjassot, Spain
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Chabrier-Roselló Y, Giesselman BR, De Jesús-Andino FJ, Foster TH, Mitra S, Haidaris CG. Inhibition of electron transport chain assembly and function promotes photodynamic killing of Candida. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2010; 99:117-25. [PMID: 20381373 DOI: 10.1016/j.jphotobiol.2010.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 01/05/2023]
Abstract
Respiratory deficiency increases the sensitivity of the pathogenic fungi Candida albicans and Candida glabrata to oxidative stress induced by photodynamic therapy (PDT) sensitized by the cationic porphyrin meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP-1363). Since disruption of electron transport chain (ETC) function increases intracellular levels of reactive oxygen species in yeast, we determined whether interference with ETC assembly or function increased sensitivity to TMP-1363-PDT in C. albicans, C. glabrata and the non-pathogenic yeast Saccharomyces cerevisiae. Metabolic inhibitor antimycin A and defined genetic mutants were used to identify ETC components that contribute to the sensitivity to PDT. Inhibition of cytochrome bc(1) (Complex III) with antimycin A increases mitochondrial levels of reactive oxygen species. PDT performed following pre-treatment with antimycin A reduced colony forming units (CFU) of C. albicans and C. glabrata by approximately two orders of magnitude relative to PDT alone. A S. cerevisiae mitochondrial glutaredoxin grx5 mutant, defective in assembly of Fe-S clusters critical for Complex III function, displayed increased sensitivity to PDT. Furthermore, C. glabrata and S.cerevisiae mutants in cytochrome c oxidase (Complex IV) synthesis and assembly were also significantly more sensitive to PDT. These included suv3, encoding an ATP-dependent RNA helicase critical for maturation of cytochrome c oxidase subunit transcripts, and pet117, encoding an essential cytochrome c oxidase assembly factor. Following PDT, the reduction in CFU of these mutants was one to two orders of magnitude greater than in their respective parental strains. The data demonstrate that selective inhibition of ETC Complexes III and IV significantly increases the sensitivity of C. albicans, C. glabrata and S. cerevisiae to PDT sensitized with TMP-1363.
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Affiliation(s)
- Yeissa Chabrier-Roselló
- Department of Microbiology and Immunology, University of Rochester Medical Center, Box 672, 601 Elmwood Ave., Rochester, NY 14642, USA
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28
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Kim KD, Chung WH, Kim HJ, Lee KC, Roe JH. Monothiol glutaredoxin Grx5 interacts with Fe–S scaffold proteins Isa1 and Isa2 and supports Fe–S assembly and DNA integrity in mitochondria of fission yeast. Biochem Biophys Res Commun 2010; 392:467-72. [DOI: 10.1016/j.bbrc.2010.01.051] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/14/2010] [Indexed: 10/20/2022]
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Iron regulation through the back door: iron-dependent metabolite levels contribute to transcriptional adaptation to iron deprivation in Saccharomyces cerevisiae. EUKARYOTIC CELL 2009; 9:460-71. [PMID: 20008079 DOI: 10.1128/ec.00213-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Budding yeast (Saccharomyces cerevisiae) responds to iron deprivation both by Aft1-Aft2-dependent transcriptional activation of genes involved in cellular iron uptake and by Cth1-Cth2-specific degradation of certain mRNAs coding for iron-dependent biosynthetic components. Here, we provide evidence for a novel principle of iron-responsive gene expression. This regulatory mechanism is based on the modulation of transcription through the iron-dependent variation of levels of regulatory metabolites. As an example, the LEU1 gene of branched-chain amino acid biosynthesis is downregulated under iron-limiting conditions through depletion of the metabolic intermediate alpha-isopropylmalate, which functions as a key transcriptional coactivator of the Leu3 transcription factor. Synthesis of alpha-isopropylmalate involves the iron-sulfur protein Ilv3, which is inactivated under iron deficiency. As another example, decreased mRNA levels of the cytochrome c-encoding CYC1 gene under iron-limiting conditions involve heme-dependent transcriptional regulation via the Hap1 transcription factor. Synthesis of the iron-containing heme is directly correlated with iron availability. Thus, the iron-responsive expression of genes that are downregulated under iron-limiting conditions is conferred by two independent regulatory mechanisms: transcriptional regulation through iron-responsive metabolites and posttranscriptional mRNA degradation. Only the combination of the two processes provides a quantitative description of the response to iron deprivation in yeast.
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Naranuntarat A, Jensen LT, Pazicni S, Penner-Hahn JE, Culotta VC. The interaction of mitochondrial iron with manganese superoxide dismutase. J Biol Chem 2009; 284:22633-40. [PMID: 19561359 PMCID: PMC2755670 DOI: 10.1074/jbc.m109.026773] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 06/24/2009] [Indexed: 01/01/2023] Open
Abstract
Superoxide dismutase 2 (SOD2) is one of the rare mitochondrial enzymes evolved to use manganese as a cofactor over the more abundant element iron. Although mitochondrial iron does not normally bind SOD2, iron will misincorporate into Saccharomyces cerevisiae Sod2p when cells are starved for manganese or when mitochondrial iron homeostasis is disrupted by mutations in yeast grx5, ssq1, and mtm1. We report here that such changes in mitochondrial manganese and iron similarly affect cofactor selection in a heterologously expressed Escherichia coli Mn-SOD, but not a highly homologous Fe-SOD. By x-ray absorption near edge structure and extended x-ray absorption fine structure analyses of isolated mitochondria, we find that misincorporation of iron into yeast Sod2p does not correlate with significant changes in the average oxidation state or coordination chemistry of bulk mitochondrial iron. Instead, small changes in mitochondrial iron are likely to promote iron-SOD2 interactions. Iron binds Sod2p in yeast mutants blocking late stages of iron-sulfur cluster biogenesis (grx5, ssq1, and atm1), but not in mutants defective in the upstream Isu proteins that serve as scaffolds for iron-sulfur biosynthesis. In fact, we observed a requirement for the Isu proteins in iron inactivation of yeast Sod2p. Sod2p activity was restored in mtm1 and grx5 mutants by depleting cells of Isu proteins or using a dominant negative Isu1p predicted to stabilize iron binding to Isu1p. In all cases where disruptions in iron homeostasis inactivated Sod2p, we observed an increase in mitochondrial Isu proteins. These studies indicate that the Isu proteins and the iron-sulfur pathway can donate iron to Sod2p.
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Affiliation(s)
- Amornrat Naranuntarat
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Laran T. Jensen
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
| | - Samuel Pazicni
- the Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | | | - Valeria C. Culotta
- From the Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 and
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Nilsson R, Schultz IJ, Pierce EL, Soltis KA, Naranuntarat A, Ward DM, Baughman J, Paradkar PN, Kingsley PD, Culotta VC, Kaplan J, Palis J, Paw BH, Mootha VK. Discovery of genes essential for heme biosynthesis through large-scale gene expression analysis. Cell Metab 2009; 10:119-30. [PMID: 19656490 PMCID: PMC2745341 DOI: 10.1016/j.cmet.2009.06.012] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 05/21/2009] [Accepted: 06/25/2009] [Indexed: 11/19/2022]
Abstract
Heme biosynthesis consists of a series of eight enzymatic reactions that originate in mitochondria and continue in the cytosol before returning to mitochondria. Although these core enzymes are well studied, additional mitochondrial transporters and regulatory factors are predicted to be required. To discover such unknown components, we utilized a large-scale computational screen to identify mitochondrial proteins whose transcripts consistently coexpress with the core machinery of heme biosynthesis. We identified SLC25A39, SLC22A4, and TMEM14C, which are putative mitochondrial transporters, as well as C1orf69 and ISCA1, which are iron-sulfur cluster proteins. Targeted knockdowns of all five genes in zebrafish resulted in profound anemia without impacting erythroid lineage specification. Moreover, silencing of Slc25a39 in murine erythroleukemia cells impaired iron incorporation into protoporphyrin IX, and vertebrate Slc25a39 complemented an iron homeostasis defect in the orthologous yeast mtm1Delta deletion mutant. Our results advance the molecular understanding of heme biosynthesis and offer promising candidate genes for inherited anemias.
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Affiliation(s)
- Roland Nilsson
- Department of Systems Biology, Harvard Medical School; Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA; and Broad Institute of MIT/Harvard, Cambridge, MA 02142 USA
| | - Iman J. Schultz
- Department of Medicine, Hematology Division, Brigham & Women’s Hospital; Hematology-Oncology Division, Children’s Hospital Boston; and Harvard Medical School, Boston, MA 02115 USA
| | - Eric L. Pierce
- Department of Medicine, Hematology Division, Brigham & Women’s Hospital; Hematology-Oncology Division, Children’s Hospital Boston; and Harvard Medical School, Boston, MA 02115 USA
| | - Kathleen A. Soltis
- Department of Medicine, Hematology Division, Brigham & Women’s Hospital; Hematology-Oncology Division, Children’s Hospital Boston; and Harvard Medical School, Boston, MA 02115 USA
| | - Amornrat Naranuntarat
- Department of Environmental Health Sciences, Toxicological Sciences Division, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Diane M. Ward
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132 USA
| | - Joshua Baughman
- Department of Systems Biology, Harvard Medical School; Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA; and Broad Institute of MIT/Harvard, Cambridge, MA 02142 USA
| | - Prasad N. Paradkar
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132 USA
| | - Paul D. Kingsley
- Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester School of Medicine & Dentistry, Rochester, NY 14642 USA
| | - Valeria C. Culotta
- Department of Environmental Health Sciences, Toxicological Sciences Division, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Jerry Kaplan
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132 USA
| | - James Palis
- Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester School of Medicine & Dentistry, Rochester, NY 14642 USA
| | - Barry H. Paw
- Department of Medicine, Hematology Division, Brigham & Women’s Hospital; Hematology-Oncology Division, Children’s Hospital Boston; and Harvard Medical School, Boston, MA 02115 USA
- Co-corresponding Authors: B.H.P., E-mail: ; V.K.M., E-mail:
| | - Vamsi K. Mootha
- Department of Systems Biology, Harvard Medical School; Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA; and Broad Institute of MIT/Harvard, Cambridge, MA 02142 USA
- Co-corresponding Authors: B.H.P., E-mail: ; V.K.M., E-mail:
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Turunen O, Seelke R, Macosko J. In silico evidence for functional specialization after genome duplication in yeast. FEMS Yeast Res 2009; 9:16-31. [PMID: 19133069 PMCID: PMC2704937 DOI: 10.1111/j.1567-1364.2008.00451.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A fairly recent whole-genome duplication (WGD) event in yeast enables the effects of gene duplication and subsequent functional divergence to be characterized. We examined 15 ohnolog pairs (i.e. paralogs from a WGD) out of c. 500 Saccharomyces cerevisiae ohnolog pairs that have persisted over an estimated 100 million years of evolution. These 15 pairs were chosen for their high levels of asymmetry, i.e. within the pair, one ohnolog had evolved much faster than the other. Sequence comparisons of the 15 pairs revealed that the faster evolving duplicated genes typically appear to have experienced partially--but not fully--relaxed negative selection as evidenced by an average nonsynonymous/synonymous substitution ratio (dN/dS(avg)=0.44) that is higher than the slow-evolving genes' ratio (dN/dS(avg)=0.14) but still <1. Increased number of insertions and deletions in the fast-evolving genes also indicated loosened structural constraints. Sequence and structural comparisons indicated that a subset of these pairs had significant differences in their catalytically important residues and active or cofactor-binding sites. A literature survey revealed that several of the fast-evolving genes have gained a specialized function. Our results indicate that subfunctionalization and even neofunctionalization has occurred along with degenerative evolution, in which unneeded functions were destroyed by mutations.
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Affiliation(s)
- Ossi Turunen
- Department of Biotechnology and Chemical Technology, Helsinki University of Technology, Espoo, Finland.
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Regulation of mitochondrial iron import through differential turnover of mitoferrin 1 and mitoferrin 2. Mol Cell Biol 2008; 29:1007-16. [PMID: 19075006 DOI: 10.1128/mcb.01685-08] [Citation(s) in RCA: 254] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitoferrin 1 and mitoferrin 2 are homologous members of the mitochondrial solute carrier family. Mitoferrin 1 is required for mitochondrial iron delivery in developing erythrocytes. Here we show that mitoferrin 1 and mitoferrin 2 contribute to mitochondrial iron delivery in a variety of cells. Reductions in mitoferrin 1 and/or mitoferrin 2 levels by RNA interference result in decreased mitochondrial iron accumulation, heme synthesis, and iron-sulfur cluster synthesis. The ectopic expression of mitoferrin 1 in nonerythroid cells silenced for mitoferrin 2 or the expression of mitoferrin 2 in cells silenced for mitoferrin 1 restored heme synthesis to "baseline" levels. The ectopic expression of mitoferrin 2, however, did not support hemoglobinization in erythroid cells deficient in mitoferrin 1. Mitoferrin 2 could not restore heme synthesis in developing erythroid cells because of an inability of the protein to accumulate in mitochondria. The half-life of mitoferrin 1 was increased in developing erythroid cells, while the half-life of mitoferrin 2 did not change. These results suggest that mitochondrial iron accumulation is tightly regulated and that controlling mitoferrin levels within the mitochondrial membrane provides a mechanism to regulate mitochondrial iron levels.
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Lill R, Mühlenhoff U. Maturation of Iron-Sulfur Proteins in Eukaryotes: Mechanisms, Connected Processes, and Diseases. Annu Rev Biochem 2008; 77:669-700. [DOI: 10.1146/annurev.biochem.76.052705.162653] [Citation(s) in RCA: 485] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Roland Lill
- Institut für Zytobiologie, Philipps Universität Marburg, Marburg D-35033, Germany;
| | - Ulrich Mühlenhoff
- Institut für Zytobiologie, Philipps Universität Marburg, Marburg D-35033, Germany;
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Abstract
V-ATPases are structurally conserved and functionally versatile proton pumps found in all eukaryotes. The yeast V-ATPase has emerged as a major model system, in part because yeast mutants lacking V-ATPase subunits (vma mutants) are viable and exhibit a distinctive Vma- phenotype. Yeast vma mutants are present in ordered collections of all non-essential yeast deletion mutants, and a number of additional phenotypes of these mutants have emerged in recent years from genomic screens. This review summarizes the many phenotypes that have been associated with vma mutants through genomic screening. The results suggest that V-ATPase activity is important for an unexpectedly wide range of cellular processes. For example, vma mutants are hypersensitive to multiple forms of oxidative stress, suggesting an antioxidant role for the V-ATPase. Consistent with such a role, vma mutants display oxidative protein damage and elevated levels of reactive oxygen species, even in the absence of an exogenous oxidant. This endogenous oxidative stress does not originate at the electron transport chain, and may be extra-mitochondrial, perhaps linked to defective metal ion homeostasis in the absence of a functional V-ATPase. Taken together, genomic data indicate that the physiological reach of the V-ATPase is much longer than anticipated. Further biochemical and genetic dissection is necessary to distinguish those physiological effects arising directly from the enzyme's core functions in proton pumping and organelle acidification from those that reflect broader requirements for cellular pH homeostasis or alternative functions of V-ATPase subunits.
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Hausmann A, Samans B, Lill R, Mühlenhoff U. Cellular and Mitochondrial Remodeling upon Defects in Iron-Sulfur Protein Biogenesis. J Biol Chem 2008; 283:8318-30. [DOI: 10.1074/jbc.m705570200] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Philpott CC, Protchenko O. Response to iron deprivation in Saccharomyces cerevisiae. EUKARYOTIC CELL 2008; 7:20-7. [PMID: 17993568 PMCID: PMC2224162 DOI: 10.1128/ec.00354-07] [Citation(s) in RCA: 186] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Caroline C Philpott
- Liver Diseases Branch, National Institutes of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 10, Room 9B-16, 10 Center Drive, MSC 1800, Bethesda, MD 20892-1800, USA.
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Cloning, functional analysis, and mitochondrial localization of Trypanosoma brucei monothiol glutaredoxin-1. Biol Chem 2008; 389:21-32. [DOI: 10.1515/bc.2007.147] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractAfrican trypanosomes encode three monothiol glutaredoxins (1-C-Grx1 to 3). 1-C-Grx1 has a putative CAYS active site and Cys181 as single additional cysteine. The recombinant protein forms non-covalent homodimers. As observed for other monothiol glutaredoxins,Trypanosoma brucei1-C-Grx1 was not active in the glutaredoxin assay with hydroxyethyl disulfide and glutathione nor catalyzed the reduction of insulin disulfide. In addition, it lacked peroxidase activity and did not catalyze protein (de)glutathionylation. Upon oxidation, 1-C-Grx1 forms an intramolecular disulfide bridge and, to a minor degree, covalent dimers. Both disulfide forms are reduced by the parasite trypanothione/tryparedoxin system. 1-C-Grx1 shows mitochondrial localization. The total cellular concentration is at least 5 μm. Thus, 1-C-Grx1 is an abundant protein especially in the rudimentary organelle of the mammalian form of the parasite. Expression of 1-C-Grx1 in Grx5-deficient yeast cells with its authentic presequence targeted the protein to the mitochondria and partially restored the growth phenotype and aconitase activity of the mutant, and conferred resistance against hydroperoxides and diamide. The parasite Grx2 and 3 failed to substitute for Grx5. This is surprising because even bacterial and plant 1-Cys-glutaredoxins efficiently revert the defects, and may be due to the lack of two basic residues conserved in all but the trypanosomatid proteins.
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Mitochondrial Iba57p is required for Fe/S cluster formation on aconitase and activation of radical SAM enzymes. Mol Cell Biol 2007; 28:1851-61. [PMID: 18086897 DOI: 10.1128/mcb.01963-07] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A genome-wide screen for Saccharomyces cerevisiae iron-sulfur (Fe/S) cluster assembly mutants identified the gene IBA57. The encoded protein Iba57p is located in the mitochondrial matrix and is essential for mitochondrial DNA maintenance. The growth phenotypes of an iba57Delta mutant and extensive functional studies in vivo and in vitro indicate a specific role for Iba57p in the maturation of mitochondrial aconitase-type and radical SAM Fe/S proteins (biotin and lipoic acid synthases). Maturation of other Fe/S proteins occurred normally in the absence of Iba57p. These observations identify Iba57p as a novel dedicated maturation factor with specificity for a subset of Fe/S proteins. The Iba57p primary sequence is distinct from any known Fe/S assembly factor but is similar to certain tetrahydrofolate-binding enzymes, adding a surprising new function to this protein family. Iba57p physically interacts with the mitochondrial ISC assembly components Isa1p and Isa2p. Since all three proteins are conserved in eukaryotes and bacteria, the specificity of the Iba57/Isa complex may represent a biosynthetic concept that is universally used in nature. In keeping with this idea, the human IBA57 homolog C1orf69 complements the iba57Delta growth defects, demonstrating its conserved function throughout the eukaryotic kingdom.
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40
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Toledano MB, Kumar C, Le Moan N, Spector D, Tacnet F. The system biology of thiol redox system inEscherichia coliand yeast: Differential functions in oxidative stress, iron metabolism and DNA synthesis. FEBS Lett 2007; 581:3598-607. [PMID: 17659286 DOI: 10.1016/j.febslet.2007.07.002] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 07/02/2007] [Indexed: 11/21/2022]
Abstract
By its ability to engage in a variety of redox reactions and coordinating metals, cysteine serves as a key residue in mediating enzymatic catalysis, protein oxidative folding and trafficking, and redox signaling. The thiol redox system, which consists of the glutathione and thioredoxin pathways, uses the cysteine residue to catalyze thiol-disulfide exchange reactions, thereby controlling the redox state of cytoplasmic cysteine residues and regulating the biological functions it subserves. Here, we consider the thiol redox systems of Escherichia coli and Saccharomyces cerevisiae, emphasizing the role of genetic approaches in the understanding of the cellular functions of these systems. We show that although prokaryotic and eukaryotic systems have a similar architecture, they profoundly differ in their overall cellular functions.
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Affiliation(s)
- Michel B Toledano
- CEA, iBiTecS, Laboratoire Stress Oxydants et Cancer, Gif sur Yvette F-91191, France.
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41
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Mühlenhoff U, Gerl MJ, Flauger B, Pirner HM, Balser S, Richhardt N, Lill R, Stolz J. The ISC [corrected] proteins Isa1 and Isa2 are required for the function but not for the de novo synthesis of the Fe/S clusters of biotin synthase in Saccharomyces cerevisiae. EUKARYOTIC CELL 2007; 6:495-504. [PMID: 17259550 PMCID: PMC1828929 DOI: 10.1128/ec.00191-06] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The yeast Saccharomyces cerevisiae is able to use some biotin precursors for biotin biosynthesis. Insertion of a sulfur atom into desthiobiotin, the final step in the biosynthetic pathway, is catalyzed by biotin synthase (Bio2). This mitochondrial protein contains two iron-sulfur (Fe/S) clusters that catalyze the reaction and are thought to act as a sulfur donor. To identify new components of biotin metabolism, we performed a genetic screen and found that Isa2, a mitochondrial protein involved in the formation of Fe/S proteins, is necessary for the conversion of desthiobiotin to biotin. Depletion of Isa2 or the related Isa1, however, did not prevent the de novo synthesis of any of the two Fe/S centers of Bio2. In contrast, Fe/S cluster assembly on Bio2 strongly depended on the Isu1 and Isu2 proteins. Both isa mutants contained low levels of Bio2. This phenotype was also found in other mutants impaired in mitochondrial Fe/S protein assembly and in wild-type cells grown under iron limitation. Low Bio2 levels, however, did not cause the inability of isa mutants to utilize desthiobiotin, since this defect was not cured by overexpression of BIO2. Thus, the Isa proteins are crucial for the in vivo function of biotin synthase but not for the de novo synthesis of its Fe/S clusters. Our data demonstrate that the Isa proteins are essential for the catalytic activity of Bio2 in vivo.
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Affiliation(s)
- Ulrich Mühlenhoff
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch-Strasse 6, 35033 Marburg, Germany
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42
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Milgrom E, Diab H, Middleton F, Kane PM. Loss of vacuolar proton-translocating ATPase activity in yeast results in chronic oxidative stress. J Biol Chem 2007; 282:7125-36. [PMID: 17215245 DOI: 10.1074/jbc.m608293200] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Yeast mutants lacking vacuolar proton-translocating ATPase (V-ATPase) subunits (vma mutants) were sensitive to several different oxidants in a recent genomic screen (Thorpe, G. W., Fong, C. S., Alic, N., Higgins, V. J., and Dawes, I. W. (2004) Proc. Natl. Acad. Sci. U. S. A. 101, 6564-6569). We confirmed that mutants lacking a V(1) subunit (vma2Delta), V(o) subunit, or either of the two V(o) a subunit isoforms are acutely sensitive to H(2)O(2) and more sensitive to menadione and diamide than wild-type cells. The vma2Delta mutant contains elevated levels of reactive oxygen species and high levels of oxidative protein damage even in the absence of an applied oxidant, suggesting an endogenous source of oxidative stress. vma2Delta mutants lacking mitochondrial DNA showed neither improved growth nor decreased sensitivity to peroxide, excluding respiration as the major source of the endogenous reactive oxygen species in the mutant. Double mutants lacking both VMA2 and components of the major cytosolic defense systems exhibited synthetic sensitivity to H(2)O(2). Microarray analysis comparing wild-type and vma2Delta mutant cells grown at pH 5, permissive conditions for the vma2Delta mutant, indicated high level up-regulation of several iron uptake and metabolism genes that are part of the Aft1/Aft2 regulon. TSA2, which encodes an isoform of the cytosolic thioredoxin peroxidase, was strongly induced, but other oxidative stress defense systems were not induced. The results indicate that V-ATPase activity helps to protect cells from endogenous oxidative stress.
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Affiliation(s)
- Elena Milgrom
- Department of Biochemistry, SUNY Upstate Medical University, Syracuse, New York 13210, USA
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Herrero E, Ros J, Tamarit J, Bellí G. Glutaredoxins in fungi. PHOTOSYNTHESIS RESEARCH 2006; 89:127-40. [PMID: 16915356 DOI: 10.1007/s11120-006-9079-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 06/09/2006] [Indexed: 05/11/2023]
Abstract
Glutaredoxins (GRXs) can be subdivided into two subfamilies: dithiol GRXs with the CPY/FC active site motif, and monothiol GRXs with the CGFS motif. Both subfamilies share a thioredoxin-fold structure. Some monothiol GRXs exist with a single-Grx domain while others have a thioredoxin-like domain (Trx) and one or more Grx domains in tandem. Most fungi have both dithiol and monothiol GRXs with different subcellular locations. GRX-like molecules also exist in fungi that differ by one residue from one of the canonical active site motifs. Additionally, Omega-class glutathione transferases (GSTs) are active as GRXs. Among fungi, the GRXs more extensively studied are those from Saccharomyces cerevisiae. This organism contains two dithiol GRXs (ScGrx1 and ScGrx2) with partially overlapping functions in defence against oxidative stress. In this function, they cooperate with GSTs Gtt1 and Gtt2. While ScGrx1 is cytosolic, two pools exist for ScGrx2, a major one at the cytosol and a minor one at mitochondria. On the other hand, S. cerevisiae cells have two monothiol GRXs with the Trx-Grx structure (ScGrx3 and ScGrx4) that locate at the nucleus and probably regulate the activity of transcription factors such as Aft1, and one monothiol GRX with the Grx structure (ScGrx5) that localizes at the mitochondrial matrix, where it participates in the synthesis of iron-sulphur clusters. The function of yeast Grx5 seems to be conserved along the evolutionary scale.
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Affiliation(s)
- Enrique Herrero
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Montserrat Roig 2, 25008, Lleida, Spain.
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44
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Kaplan J, McVey Ward D, Crisp RJ, Philpott CC. Iron-dependent metabolic remodeling in S. cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:646-51. [PMID: 16697062 DOI: 10.1016/j.bbamcr.2006.03.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/28/2006] [Accepted: 03/29/2006] [Indexed: 10/24/2022]
Abstract
All eukaryotes require iron although iron is not readily bioavailable. Organisms expend much effort in acquiring iron and in response have evolved multiple mechanisms to acquire iron. Because iron is essential, organisms prioritize the iron use when iron is limiting; iron-sparing enzymes or metabolic pathways are utilized at the expense of iron-rich enzymes. A large percentage of cellular iron containing proteins is devoted to oxygen binding or metabolism, therefore, changes in oxygen availability affect iron usage. Transcriptional and post-transcriptional mechanisms have been shown to affect the concentration of iron-containing proteins under iron or oxygen limiting conditions. In this review, we describe how the budding yeast Saccharomyces cerevisiae utilizes multiple mechanisms to optimize iron usage under iron limiting conditions.
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Affiliation(s)
- Jerry Kaplan
- Department of Pathology, School of Medicine University of Utah, Salt Lake City, UT 84132-2501, USA.
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45
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Weider M, Machnik A, Klebl F, Sauer N. Vhr1p, a New Transcription Factor from Budding Yeast, Regulates Biotin-dependent Expression of VHT1 and BIO5. J Biol Chem 2006; 281:13513-13524. [PMID: 16533810 DOI: 10.1074/jbc.m512158200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription of the Saccharomyces cerevisiae vitamin H transporter gene VHT1 is enhanced by low extracellular biotin. Here we present the identification and characterization of Vhr1p as a transcriptional regulator of VHT1 (VHR1 (YIL056w); VHT1 regulator 1) and the identification of the cis-regulatory target sequences for Vhr1p in two yeast promoters. VHR1 was identified in a complementation screening of mutagenized yeast cells that had lost the capacity to express the gene of the green fluorescent protein (GFP) from the VHT1 promoter. Deltavhr1 deletion mutants fail to induce VHT1 on low biotin concentrations. In yeast one-hybrid analyses performed with fusions of Vhr1p N-terminal and C-terminal fragments to the Gal4p activation domain or to the Gal4p DNA-binding domain, the Vhr1p N terminus mediated biotin-dependent DNA binding, and the Vhr1p C terminus triggered biotin-dependent transcriptional activation. The analyzed Vhr1p N-terminal fragment has previously been described as a domain of unknown function (DUF352). Deletion and linker scanning analyses of the VHT1 promoter revealed the palindromic 18-nucleotide sequence AATCA-N8-TGAYT as the vitamin H-responsive element. This sequence was identified also in the BIO5 promoter that is also transcriptionally activated on low biotin concentrations. Bio5p mediates the transport of 7-keto-8-aminopelargonic acid across the yeast plasma membrane, a compound that is used as a precursor in biotin biosynthesis. Deltavhr1 deletion mutants fail to induce BIO5 on low biotin concentrations. The presented data characterize Vhr1p as an essential component of the biotin-dependent signal transduction cascade in yeast.
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Affiliation(s)
- Matthias Weider
- Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Agnes Machnik
- Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Franz Klebl
- Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Norbert Sauer
- Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany.
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Ojeda L, Keller G, Muhlenhoff U, Rutherford JC, Lill R, Winge DR. Role of glutaredoxin-3 and glutaredoxin-4 in the iron regulation of the Aft1 transcriptional activator in Saccharomyces cerevisiae. J Biol Chem 2006; 281:17661-9. [PMID: 16648636 DOI: 10.1074/jbc.m602165200] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The transcription factors Aft1 and Aft2 from Saccharomyces cerevisiae regulate the expression of genes involved in iron homeostasis. These factors induce the expression of iron regulon genes in iron-deficient yeast but are inactivated in iron-replete cells. Iron inhibition of Aft1/Aft2 was previously shown to be dependent on mitochondrial components required for cytosolic iron sulfur protein biogenesis. We presently show that the nuclear monothiol glutaredoxins Grx3 and Grx4 are critical for iron inhibition of Aft1 in yeast cells. Cells lacking both glutaredoxins show constitutive expression of iron regulon genes. Overexpression of Grx4 attenuates wild type Aft1 activity. The thioredoxin-like domain in Grx3 and Grx4 is dispensable in mediating iron inhibition of Aft1 activity, whereas the conserved cysteine that is part of the conserved CGFS motif in monothiol glutaredoxins is essential for this function. Grx3 and Grx4 interact with Aft1 as shown by two-hybrid interactions and co-immunoprecipitation assays. The interaction between glutaredoxins and Aft1 is not modulated by the iron status of cells but is dependent on the conserved glutaredoxin domain Cys residue. Thus, Grx3 and Grx4 are novel components required for Aft1 iron regulation that most likely occurs in the nucleus.
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Affiliation(s)
- Luis Ojeda
- Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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47
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Yang M, Cobine PA, Molik S, Naranuntarat A, Lill R, Winge DR, Culotta VC. The effects of mitochondrial iron homeostasis on cofactor specificity of superoxide dismutase 2. EMBO J 2006; 25:1775-83. [PMID: 16601688 PMCID: PMC1440838 DOI: 10.1038/sj.emboj.7601064] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Accepted: 03/07/2006] [Indexed: 01/03/2023] Open
Abstract
Many metalloproteins have the capacity to bind diverse metals, but in living cells connect only with their cognate metal cofactor. In eukaryotes, this metal specificity can be achieved through metal-specific metallochaperone proteins. Herein, we describe a mechanism whereby Saccharomyces cerevisiae manganese superoxide dismutase (SOD2) preferentially binds manganese over iron based on the differential bioavailability of these ions within mitochondria. The bulk of mitochondrial iron is normally unavailable to SOD2, but when mitochondrial iron homeostasis is disrupted, for example, by mutations in S. cerevisiae mtm1, ssq1 and grx5, iron accumulates in a reactive form that potently competes with manganese for binding to SOD2, inactivating the enzyme. Studies in mtm1 mutants indicate that iron inactivation of SOD2 involves the Mrs3p/Mrs4p mitochondrial carriers and iron-binding frataxin (Yfh1p). A small pool of SOD2-reactive iron also exists under normal iron homeostasis conditions and binds SOD2 when mitochondrial manganese is low. The ability to control this reactive pool of iron is critical to maintaining SOD2 activity and has important potential implications for oxidative stress in disorders of iron overload.
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Affiliation(s)
- Mei Yang
- Division of Toxicological Sciences, Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Paul A Cobine
- Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
- Department of Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
| | - Sabine Molik
- Institut fur Zytobiologie, Philipps-Universitat Marburg, Germany
| | - Amornrat Naranuntarat
- Division of Toxicological Sciences, Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Roland Lill
- Institut fur Zytobiologie, Philipps-Universitat Marburg, Germany
| | - Dennis R Winge
- Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
- Department of Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
| | - Valeria C Culotta
- Division of Toxicological Sciences, Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
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48
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Staleva L, Hall A, Orlow SJ. Oxidative stress activates FUS1 and RLM1 transcription in the yeast Saccharomyces cerevisiae in an oxidant-dependent Manner. Mol Biol Cell 2004; 15:5574-82. [PMID: 15385622 PMCID: PMC532035 DOI: 10.1091/mbc.e04-02-0142] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2004] [Revised: 09/01/2004] [Accepted: 09/13/2004] [Indexed: 12/22/2022] Open
Abstract
Mating in haploid Saccharomyces cerevisiae occurs after activation of the pheromone response pathway. Biochemical components of this pathway are involved in other yeast signal transduction networks. To understand more about the coordination between signaling pathways, we used a "chemical genetic" approach, searching for compounds that would activate the pheromone-responsive gene FUS1 and RLM1, a reporter for the cell integrity pathway. We found that catecholamines (l-3,4-hydroxyphenylalanine [l-dopa], dopamine, adrenaline, and noradrenaline) elevate FUS1 and RLM1 transcription. N-Acetyl-cysteine, a powerful antioxidant in yeast, completely reversed this effect, suggesting that FUS1 and RLM1 activation in response to catecholamines is a result of oxidative stress. The oxidant hydrogen peroxide also was found to activate transcription of an RLM1 reporter. Further genetic analysis combined with immunoblotting revealed that Kss1, one of the mating mitogen-activated protein kinases (MAPKs), and Mpk1, an MAPK of the cell integrity pathway, participated in l-dopa-induced stimulation of FUS1 and RLM1 transcription. We also report that Mpk1 and Hog1, the high osmolarity MAPK, were phosphorylated upon induction by hydrogen peroxide. Together, our results demonstrate that cells respond to oxidative stress via different signal transduction machinery dependent upon the nature of the oxidant.
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Affiliation(s)
- Liliana Staleva
- Department of Dermatology, New York University School of Medicine, New York, NY 10016, USA
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