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Li J, Xia Y, Wei B, Shen W, Yang H, Chen X. Metabolic engineering of Candida tropicalis for efficient 1,2,4-butanetriol production. Biochem Biophys Res Commun 2024; 710:149876. [PMID: 38579537 DOI: 10.1016/j.bbrc.2024.149876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 03/31/2024] [Indexed: 04/07/2024]
Abstract
1,2,4-Butanetriol serves as a precursor in the manufacture of diverse pharmaceuticals and the energetic plasticizer 1,2,4-butanetriol trinitrate. The study involved further modifications to an engineered Candida tropicalis strain, aimed at improving the production efficiency of 1,2,4-butanetriol. Faced with the issue of xylonate accumulation due to the low activity of heterologous xylonate dehydratase, we modulated iron metabolism at the transcriptional level to boost intracellular iron ion availability, thus enhancing the enzyme activity by 2.2-fold. Addressing the NADPH shortfall encountered during 1,2,4-butanetriol biosynthesis, we overexpressed pivotal genes in the NADPH regeneration pathway, achieving a 1,2,4-butanetriol yield of 3.2 g/L. The introduction of calcium carbonate to maintain pH balance led to an increased yield of 4 g/L, marking a 111% improvement over the baseline strain. Finally, the use of corncob hydrolysate as a substrate culminated in 1,2,4-butanetriol production of 3.42 g/L, thereby identifying a novel host for the conversion of corncob hydrolysate to 1,2,4-butanetriol.
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Affiliation(s)
- Jingyun Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Yuanyuan Xia
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Bo Wei
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Wei Shen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Haiquan Yang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xianzhong Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, & School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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2
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Hati D, Brault A, Gupta M, Fletcher K, Jacques JF, Labbé S, Outten CE. Iron homeostasis proteins Grx4 and Fra2 control activity of the Schizosaccharomyces pombe iron repressor Fep1 by facilitating [2Fe-2S] cluster removal. J Biol Chem 2023; 299:105419. [PMID: 37923140 PMCID: PMC10704371 DOI: 10.1016/j.jbc.2023.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/12/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023] Open
Abstract
The Bol2 homolog Fra2 and monothiol glutaredoxin Grx4 together play essential roles in regulating iron homeostasis in Schizosaccharomyces pombe. In vivo studies indicate that Grx4 and Fra2 act as coinhibitory partners that inactivate the transcriptional repressor Fep1 in response to iron deficiency. In Saccharomyces cerevisiae, Bol2 is known to form a [2Fe-2S]-bridged heterodimer with the monothiol Grxs Grx3 and Grx4, with the cluster ligands provided by conserved residues in Grx3/4 and Bol2 as well as GSH. In this study, we characterized this analogous [2Fe-2S]-bridged Grx4-Fra2 complex in S. pombe by identifying the specific residues in Fra2 that act as ligands for the Fe-S cluster and are required to regulate Fep1 activity. We present spectroscopic and biochemical evidence confirming the formation of a [2Fe-2S]-bridged Grx4-Fra2 heterodimer with His66 and Cys29 from Fra2 serving as Fe-S cluster ligands in S. pombe. In vivo transcription and growth assays confirm that both His66 and Cys29 are required to fully mediate the response of Fep1 to low iron conditions. Furthermore, we analyzed the interaction between Fep1 and Grx4-Fra2 using CD spectroscopy to monitor changes in Fe-S cluster coordination chemistry. These experiments demonstrate unidirectional [2Fe-2S] cluster transfer from Fep1 to Grx4-Fra2 in the presence of GSH, revealing the Fe-S cluster dependent mechanism of Fep1 inactivation mediated by Grx4 and Fra2 in response to iron deficiency.
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Affiliation(s)
- Debolina Hati
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Ariane Brault
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Malini Gupta
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Kylie Fletcher
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Jean-François Jacques
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Simon Labbé
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA.
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3
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McCotter SW, Kretschmer M, Lee CWJ, Heimel K, Kronstad JW. The Monothiol Glutaredoxin Grx4 Influences Iron Homeostasis and Virulence in Ustilago maydis. J Fungi (Basel) 2023; 9:1112. [PMID: 37998917 PMCID: PMC10672361 DOI: 10.3390/jof9111112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
The corn smut fungus, Ustilago maydis, is an excellent model for studying biotrophic plant-pathogen interactions, including nutritional adaptation to the host environment. Iron acquisition during host colonization is a key aspect of microbial pathogenesis yet less is known about this process for fungal pathogens of plants. Monothiol glutaredoxins are central regulators of key cellular functions in fungi, including iron homeostasis, cell wall integrity, and redox status via interactions with transcription factors, iron-sulfur clusters, and glutathione. In this study, the roles of the monothiol glutaredoxin Grx4 in the biology of U. maydis were investigated by constructing strains expressing a conditional allele of grx4 under the control of the arabinose-inducible, glucose-repressible promoter Pcrg1. The use of conditional expression was necessary because Grx4 appeared to be essential for U. maydis. Transcriptome and genetic analyses with strains depleted in Grx4 revealed that the protein participates in the regulation of iron acquisition functions and is necessary for the ability of U. maydis to cause disease on maize seedlings. Taken together, this study supports the growing appreciation of monothiol glutaredoxins as key regulators of virulence-related phenotypes in pathogenic fungi.
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Affiliation(s)
- Sean W. McCotter
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada; (S.W.M.); (M.K.); (C.W.J.L.)
| | - Matthias Kretschmer
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada; (S.W.M.); (M.K.); (C.W.J.L.)
| | - Christopher W. J. Lee
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada; (S.W.M.); (M.K.); (C.W.J.L.)
| | - Kai Heimel
- Institute of Microbiology and Genetics, Department of Microbial Cell Biology, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada; (S.W.M.); (M.K.); (C.W.J.L.)
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4
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Pijuan J, Moreno DF, Yahya G, Moisa M, Ul Haq I, Krukiewicz K, Mosbah R, Metwally K, Cavalu S. Regulatory and pathogenic mechanisms in response to iron deficiency and excess in fungi. Microb Biotechnol 2023; 16:2053-2071. [PMID: 37804207 PMCID: PMC10616654 DOI: 10.1111/1751-7915.14346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 10/09/2023] Open
Abstract
Iron is an essential element for all eukaryote organisms because of its redox properties, which are important for many biological processes such as DNA synthesis, mitochondrial respiration, oxygen transport, lipid, and carbon metabolism. For this reason, living organisms have developed different strategies and mechanisms to optimally regulate iron acquisition, transport, storage, and uptake in different environmental responses. Moreover, iron plays an essential role during microbial infections. Saccharomyces cerevisiae has been of key importance for decrypting iron homeostasis and regulation mechanisms in eukaryotes. Specifically, the transcription factors Aft1/Aft2 and Yap5 regulate the expression of genes to control iron metabolism in response to its deficiency or excess, adapting to the cell's iron requirements and its availability in the environment. We also review which iron-related virulence factors have the most common fungal human pathogens (Aspergillus fumigatus, Cryptococcus neoformans, and Candida albicans). These factors are essential for adaptation in different host niches during pathogenesis, including different fungal-specific iron-uptake mechanisms. While being necessary for virulence, they provide hope for developing novel antifungal treatments, which are currently scarce and usually toxic for patients. In this review, we provide a compilation of the current knowledge about the metabolic response to iron deficiency and excess in fungi.
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Affiliation(s)
- Jordi Pijuan
- Laboratory of Neurogenetics and Molecular MedicineInstitut de Recerca Sant Joan de DéuBarcelonaSpain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIIIMadridSpain
| | - David F. Moreno
- Department of Molecular Cellular and Developmental BiologyYale UniversityNew HavenConnecticutUSA
- Systems Biology InstituteYale UniversityWest HavenConnecticutUSA
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
| | - Galal Yahya
- Department of Microbiology and Immunology, Faculty of PharmacyZagazig UniversityAl SharqiaEgypt
| | - Mihaela Moisa
- Faculty of Medicine and PharmacyUniversity of OradeaOradeaRomania
| | - Ihtisham Ul Haq
- Department of Physical Chemistry and Polymers TechnologySilesian University of TechnologyGliwicePoland
- Programa de Pós‐graduação em Inovação TecnológicaUniversidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Katarzyna Krukiewicz
- Department of Physical Chemistry and Polymers TechnologySilesian University of TechnologyGliwicePoland
- Centre for Organic and Nanohybrid ElectronicsSilesian University of TechnologyGliwicePoland
| | - Rasha Mosbah
- Infection Control UnitHospitals of Zagazig UniversityZagazigEgypt
| | - Kamel Metwally
- Department of Medicinal Chemistry, Faculty of PharmacyUniversity of TabukTabukSaudi Arabia
- Department of Pharmaceutical Medicinal Chemistry, Faculty of PharmacyZagazig UniversityZagazigEgypt
| | - Simona Cavalu
- Faculty of Medicine and PharmacyUniversity of OradeaOradeaRomania
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5
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Rakhmanova TI, Sekova VY, Gessler NN, Isakova EP, Deryabina YI, Popova TN, Shurubor YI, Krasnikov BF. Kinetic and Regulatory Properties of Yarrowia lipolytica Aconitate Hydratase as a Model-Indicator of Cell Redox State under pH Stress. Int J Mol Sci 2023; 24:ijms24087670. [PMID: 37108831 PMCID: PMC10143702 DOI: 10.3390/ijms24087670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 04/29/2023] Open
Abstract
This paper presents an analysis of the regulation activity of the partially purified preparations of cellular aconitate hydratase (AH) on the yeast Yarrowia lipolytica cultivated at extreme pH. As a result of purification, enzyme preparations were obtained from cells grown on media at pH 4.0, 5.5, and 9.0, purified by 48-, 46-, and 51-fold and having a specific activity of 0.43, 0.55 and 0.36 E/mg protein, respectively. The kinetic parameters of preparations from cells cultured at extreme pH demonstrated: (1) an increase in the affinity for citrate and isocitrate; and (2) a shift in the pH optima to the acidic and alkaline side in accordance with the modulation of the medium pH. The regulatory properties of the enzyme from cells subjected to alkaline stress showed increased sensitivity to Fe2+ ions and high peroxide resistance. Reduced glutathione (GSH) stimulated AH, while oxidized glutathione (GSSG) inhibited AH. A more pronounced effect of both GSH and GSSG was noted for the enzyme obtained from cells grown at pH 5.5. The data obtained provide new approaches to the use of Y. lipolytica as a model of eukaryotic cells demonstrating the development of a stress-induced pathology and to conducting a detailed analysis of enzymatic activity for its correction.
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Affiliation(s)
- Tatyana I Rakhmanova
- Department of Medical Biochemistry and Microbiology, Biology and Soil Science Faculty, Voronezh State University, Universitetskaya pl., 1, 394000 Voronezh, Russia
| | - Varvara Yu Sekova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Natalya N Gessler
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Elena P Isakova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Yulia I Deryabina
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Tatyana N Popova
- Department of Medical Biochemistry and Microbiology, Biology and Soil Science Faculty, Voronezh State University, Universitetskaya pl., 1, 394000 Voronezh, Russia
| | - Yevgeniya I Shurubor
- Centre for Strategic Planning of FMBA of the Russian Federation, Pogodinskaya St., Bld.10, 119121 Moscow, Russia
| | - Boris F Krasnikov
- Centre for Strategic Planning of FMBA of the Russian Federation, Pogodinskaya St., Bld.10, 119121 Moscow, Russia
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6
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Kuno S, Iwai K. Oxygen modulates iron homeostasis by switching iron-sensing of NCOA4. J Biol Chem 2023; 299:104701. [PMID: 37059186 DOI: 10.1016/j.jbc.2023.104701] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/31/2023] [Accepted: 04/05/2023] [Indexed: 04/16/2023] Open
Abstract
To ensure proper utilization of iron and avoid its toxicity, cells are equipped with iron-sensing proteins to maintain cellular iron homeostasis. We showed previously that NCOA4, a ferritin-specific autophagy adapter, intricately regulates the fate of ferritin; upon binding to Fe3+, NCOA4 forms insoluble condensates and regulates ferritin autophagy in iron-replete conditions. Here, we demonstrate an additional iron-sensing mechanism of NCOA4. Our results indicate that the insertion of an Fe-S cluster enables preferential recognition of NCOA4 by the HERC2 ubiquitin ligase in iron-replete conditions, resulting in degradation by the proteasome and subsequent inhibition of ferritinophagy. We also found that both condensation and ubiquitin-mediated degradation of NCOA4 can occur in the same cell, and the cellular oxygen tension determines the selection of these pathways. Fe-S cluster-mediated degradation of NCOA4 is enhanced under hypoxia, whereas NCOA4 forms condensates and degrades ferritin at higher oxygen levels. Considering the involvement of iron in oxygen handling, our findings demonstrate that the NCOA4/ferritin axis is another layer of cellular iron regulation in response to oxygen levels.
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Affiliation(s)
- Sota Kuno
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhiro Iwai
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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7
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Aft1 Nuclear Localization and Transcriptional Response to Iron Starvation Rely upon TORC2/Ypk1 Signaling and Sphingolipid Biosynthesis. Int J Mol Sci 2023; 24:ijms24032438. [PMID: 36768760 PMCID: PMC9916926 DOI: 10.3390/ijms24032438] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
Iron scarcity provokes a cellular response consisting of the strong expression of high-affinity systems to optimize iron uptake and mobilization. Aft1 is a primary transcription factor involved in iron homeostasis and controls the expression of high-affinity iron uptake genes in Saccharomyces cerevisiae. Aft1 responds to iron deprivation by translocating from the cytoplasm to the nucleus. Here, we demonstrate that the AGC kinase Ypk1, as well as its upstream regulator TOR Complex 2 (TORC2), are required for proper Aft1 nuclear localization following iron deprivation. We exclude a role for TOR Complex 1 (TORC1) and its downstream effector Sch9, suggesting this response is specific for the TORC2 arm of the TOR pathway. Remarkably, we demonstrate that Aft1 nuclear localization and a robust transcriptional response to iron starvation also require biosynthesis of sphingolipids, including complex sphingolipids such as inositol phosphorylceramide (IPC) and upstream precursors, e.g., long-chain bases (LCBs) and ceramides. Furthermore, we observe the deficiency of Aft1 nuclear localization and impaired transcriptional response in the absence of iron when TORC2-Ypk1 is impaired is partially suppressed by exogenous addition of the LCB dihydrosphingosine (DHS). This latter result is consistent with prior studies linking sphingolipid biosynthesis to TORC2-Ypk1 signaling. Taken together, these results reveal a novel role for sphingolipids, controlled by TORC2-Ypk1, for proper localization and activity of Aft1 in response to iron scarcity.
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8
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The polyHIS Tract of Yeast AMPK Coordinates Carbon Metabolism with Iron Availability. Int J Mol Sci 2023; 24:ijms24021368. [PMID: 36674878 PMCID: PMC9863760 DOI: 10.3390/ijms24021368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 01/13/2023] Open
Abstract
Energy status in all eukaryotic cells is sensed by AMP-kinases. We have previously found that the poly-histidine tract at the N-terminus of S. cerevisiae AMPK (Snf1) inhibits its function in the presence of glucose via a pH-regulated mechanism. We show here that in the absence of glucose, the poly-histidine tract has a second function, linking together carbon and iron metabolism. Under conditions of iron deprivation, when different iron-intense cellular systems compete for this scarce resource, Snf1 is inhibited. The inhibition is via an interaction of the poly-histidine tract with the low-iron transcription factor Aft1. Aft1 inhibition of Snf1 occurs in the nucleus at the nuclear membrane, and only inhibits nuclear Snf1, without affecting cytosolic Snf1 activities. Thus, the temporal and spatial regulation of Snf1 activity enables a differential response to iron depending upon the type of carbon source. The linkage of nuclear Snf1 activity to iron sufficiency ensures that sufficient clusters are available to support respiratory enzymatic activity and tests mitochondrial competency prior to activation of nuclear Snf1.
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9
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Deficiency of the RNA-binding protein Cth2 extends yeast replicative lifespan by alleviating its repressive effects on mitochondrial function. Cell Rep 2022; 40:111113. [PMID: 35858543 PMCID: PMC9382658 DOI: 10.1016/j.celrep.2022.111113] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/18/2022] [Accepted: 06/28/2022] [Indexed: 12/13/2022] Open
Abstract
Iron dyshomeostasis contributes to aging, but little information is available about the molecular mechanisms. Here, we provide evidence that in Saccharomyces cerevisiae, aging is associated with altered expression of genes involved in iron homeostasis. We further demonstrate that defects in the conserved mRNA-binding protein Cth2, which controls stability and translation of mRNAs encoding iron-containing proteins, increase lifespan by alleviating its repressive effects on mitochondrial function. Mutation of the conserved cysteine residue in Cth2 that inhibits its RNA-binding activity is sufficient to confer longevity, whereas Cth2 gain of function shortens replicative lifespan. Consistent with its function in RNA degradation, Cth2 deficiency relieves Cth2-mediated post-transcriptional repression of nuclear-encoded components of the electron transport chain. Our findings uncover a major role of the RNA-binding protein Cth2 in the regulation of lifespan and suggest that modulation of iron starvation signaling can serve as a target for potential aging interventions. Dysregulation of iron homeostasis contributes to aging, but little information is available about the molecular mechanisms. Here, Patnaik et al. show that the mRNA-binding protein Cth2, which is involved in regulation of iron-dependent genes, is induced during aging and links impaired iron homeostasis with an age-related decline of mitochondrial function.
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10
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Kobayashi T, Shinkawa H, Nagano AJ, Nishizawa NK. The basic leucine zipper transcription factor OsbZIP83 and the glutaredoxins OsGRX6 and OsGRX9 facilitate rice iron utilization under the control of OsHRZ ubiquitin ligases. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:1731-1750. [PMID: 35411594 DOI: 10.1111/tpj.15767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 04/06/2022] [Indexed: 05/16/2023]
Abstract
Under low iron availability, plants induce the expression of various genes for iron uptake and translocation. The rice (Oryza sativa) ubiquitin ligases OsHRZ1 and OsHRZ2 cause overall repression of these iron-related genes at the transcript level, but their protein-level regulation is unclear. We conducted a proteome analysis to identify key regulators whose abundance was regulated by OsHRZs at the protein level. In response to iron deficiency or OsHRZ knockdown, many genes showed differential regulation between the transcript and protein levels, including the TGA-type basic leucine zipper transcription factor OsbZIP83. We also identified two glutaredoxins, OsGRX6 and OsGRX9, as OsHRZ-interacting proteins in yeast and plant cells. OsGRX6 also interacted with OsbZIP83. Our in vitro degradation assay suggested that OsbZIP83, OsGRX6 and OsGRX9 proteins are subjected to 26S proteasome- and OsHRZ-dependent degradation. Proteome analysis and our in vitro degradation assay also suggested that OsbZIP83 protein was preferentially degraded under iron-deficient conditions in rice roots. Transgenic rice lines overexpressing OsGRX9 and OsbZIP83 showed improved tolerance to iron deficiency. Expression of iron-related genes was affected in the OsGRX9 and OsGRX6 knockdown lines, suggesting disturbed iron utilization and signaling. OsbZIP83 overexpression lines showed enhanced expression of OsYSL2 and OsNAS3, which are involved in internal iron translocation, in addition to OsGRX9 and genes related to phytoalexin biosynthesis and the salicylic acid pathway. The results suggest that OsbZIP83, OsGRX6 and OsGRX9 facilitate iron utilization downstream of the OsHRZ pathway.
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Affiliation(s)
- Takanori Kobayashi
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Haruka Shinkawa
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Atsushi J Nagano
- Faculty of Agriculture, Ryukoku University, Otsu, Shiga, 520-2194, Japan
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
| | - Naoko K Nishizawa
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
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11
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Mühlenhoff U, Braymer JJ, Christ S, Rietzschel N, Uzarska MA, Weiler BD, Lill R. Glutaredoxins and iron-sulfur protein biogenesis at the interface of redox biology and iron metabolism. Biol Chem 2021; 401:1407-1428. [PMID: 33031050 DOI: 10.1515/hsz-2020-0237] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/21/2020] [Indexed: 11/15/2022]
Abstract
The physiological roles of the intracellular iron and redox regulatory systems are intimately linked. Iron is an essential trace element for most organisms, yet elevated cellular iron levels are a potent generator and amplifier of reactive oxygen species and redox stress. Proteins binding iron or iron-sulfur (Fe/S) clusters, are particularly sensitive to oxidative damage and require protection from the cellular oxidative stress protection systems. In addition, key components of these systems, most prominently glutathione and monothiol glutaredoxins are involved in the biogenesis of cellular Fe/S proteins. In this review, we address the biochemical role of glutathione and glutaredoxins in cellular Fe/S protein assembly in eukaryotic cells. We also summarize the recent developments in the role of cytosolic glutaredoxins in iron metabolism, in particular the regulation of fungal iron homeostasis. Finally, we discuss recent insights into the interplay of the cellular thiol redox balance and oxygen with that of Fe/S protein biogenesis in eukaryotes.
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Affiliation(s)
- Ulrich Mühlenhoff
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany.,SYNMIKRO Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Str., D-35043Marburg, Germany
| | - Joseph J Braymer
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany.,SYNMIKRO Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Str., D-35043Marburg, Germany
| | - Stefan Christ
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany
| | - Nicole Rietzschel
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany
| | - Marta A Uzarska
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany.,Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307Gdansk, Poland
| | - Benjamin D Weiler
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35032Marburg, Germany.,SYNMIKRO Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Str., D-35043Marburg, Germany
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12
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Casting iron into the cell fate mold. Biochem J 2021; 478:1879-1883. [PMID: 34029365 DOI: 10.1042/bcj20210108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 11/17/2022]
Abstract
This commentary discusses general concepts introduced in the article 'Bulk autophagy induction and life extension is achieved when iron is the only limited nutrient in Saccharomyces cerevisiae' by Montella-Manuel et al. (Biochem J (2021) 478: 811-837). Montella-Manuel et al. show that like central carbon metabolism, iron metabolism is also closely implicated in autophagy-mediated life extension via the TORC2 activator Ypk1p and the iron regulator Aft1p. While not being an iron-sulfur cluster protein, Aft1p interacts with such proteins and thus senses the redox status of the cell, which, similar to amino acids and AMP, reports its energetic status. Furthermore, glucose and iron deficiencies are interrelated as the diauxic shift in glucose depleted cells requires iron uptake for activating respiration in the absence of fermentation.
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13
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Pujol-Carrion N, Pavón-Vergés M, Arroyo J, de la Torre-Ruiz MA. The MAPK Slt2/Mpk1 plays a role in iron homeostasis through direct regulation of the transcription factor Aft1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118974. [PMID: 33549702 DOI: 10.1016/j.bbamcr.2021.118974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 01/14/2021] [Accepted: 01/28/2021] [Indexed: 01/18/2023]
Abstract
Iron is an essential element for life. Cells develop mechanisms to tightly regulate its homeostasis, in order to avoid abnormal accumulation and the consequent cell toxicity. In budding yeast, the high affinity iron regulon is under the control of the transcription factor Aft1. We present evidence demonstrating that the MAPK Slt2 of the cell wall integrity pathway (CWI), phosphorylates and negatively regulates Aft1 activity upon the iron depletion signal, both in fermentative or respiratory conditions. The lack of Slt2 provokes Aft1 dysfunction leading to a shorter chronological life span. The signal of iron scarcity is not transmitted to Slt2 through other signalling pathways such as TOR1, PKA, SNF1 or TOR2/YPK1. The observation that Slt2 physically binds Aft1 rather suggests a direct regulation.
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Affiliation(s)
- Nuria Pujol-Carrion
- Cell Signalling in Yeast Unit, Department of Basic Medical Sciences, Institut de Recerca Biomèdica de Lleida (IRBLleida), University of Lleida, 25198 Lleida, Spain
| | - Mónica Pavón-Vergés
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University Complutense de Madrid, IRYCIS, 28040 Madrid, Spain
| | - Javier Arroyo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University Complutense de Madrid, IRYCIS, 28040 Madrid, Spain
| | - Maria Angeles de la Torre-Ruiz
- Cell Signalling in Yeast Unit, Department of Basic Medical Sciences, Institut de Recerca Biomèdica de Lleida (IRBLleida), University of Lleida, 25198 Lleida, Spain.
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14
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Basics of Fungal Siderophores: Classification, Iron Transport and Storage, Chemistry and Biosynthesis, Application, and More. Fungal Biol 2021. [DOI: 10.1007/978-3-030-53077-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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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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16
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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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17
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Martínez-Pastor MT, Puig S. Adaptation to iron deficiency in human pathogenic fungi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118797. [PMID: 32663505 DOI: 10.1016/j.bbamcr.2020.118797] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/13/2020] [Accepted: 07/05/2020] [Indexed: 02/08/2023]
Abstract
Iron is an essential micronutrient for virtually all eukaryotic organisms and plays a central role during microbial infections. Invasive fungal diseases are associated with strikingly high rates of mortality, but their impact on human health is usually underestimated. Upon a fungal infection, hosts restrict iron availability in order to limit the growth and virulence of the pathogen. Here, we use two model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, to delve into the response to iron deficiency of human fungal pathogens, such as Candida glabrata, Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. Fungi possess common and species-specific mechanisms to acquire iron and to control the response to iron limitation. Upon iron scarcity, fungi activate a wide range of elegant strategies to capture and import exogenous iron, mobilize iron from intracellular stores, and modulate their metabolism to economize and prioritize iron utilization. Hence, iron homeostasis genes represent remarkable virulence factors that can be used as targets for the development of novel antifungal treatments.
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Affiliation(s)
| | - 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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18
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Interactions of GMP with Human Glrx3 and with Saccharomyces cerevisiae Grx3 and Grx4 Converge in the Regulation of the Gcn2 Pathway. Appl Environ Microbiol 2020; 86:AEM.00221-20. [PMID: 32414791 DOI: 10.1128/aem.00221-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 04/24/2020] [Indexed: 11/20/2022] Open
Abstract
The human monothiol glutaredoxin Glrx3 (PICOT) is ubiquitously distributed in cytoplasm and nuclei in mammalian cells. Its overexpression has been associated with the development of several types of tumors, whereas its deficiency might cause retardation in embryogenesis. Its exact biological role has not been well resolved, although a function as a chaperone distributing iron/sulfur clusters is currently accepted. Yeast humanization and the use of a mouse library have allowed us to find a new partner for PICOT: the human GMP synthase (hGMPs). Both proteins carry out collaborative functions regarding the downregulation of the Saccharomyces cerevisiae Gcn2 pathway under conditions of nutritional stress. Glrx3/hGMPs interact through conserved residues that bridge iron/sulfur clusters and glutathione. This mechanism is also conserved in budding yeast, whose proteins Grx3/Grx4, along with GUA1 (S. cerevisiae GMPs), also downregulate the integrated stress response (ISR) pathway. The heterologous expression of Glrx3/hGMPs efficiently complements Grx3/Grx4. Moreover, the heterologous expression of Glrx3 efficiently complements the novel participation in chronological life span that has been characterized for both Grx3 and Grx4. Our results underscore that the Glrx3/Grx3/Grx4 family presents an evolutionary and functional conservation in signaling events that is partly related to GMP function and contributes to cell life extension.IMPORTANCE Saccharomyces cerevisiae is an optimal eukaryotic microbial model to study biological processes in higher organisms despite the divergence in evolution. The molecular function of yeast glutaredoxins Grx3 and Grx4 is enormously interesting, since both proteins are required to maintain correct iron homeostasis and an efficient response to oxidative stress. The human orthologous Glrx3 (PICOT) is involved in a number of human diseases, including cancer. Our research expanded its utility to human cells. Yeast has allowed the characterization of GMP synthase as a new interacting partner for Glrx3 and also for yeast Grx3 and Grx4, the complex monothiol glutaredoxins/GMPs that participate in the downregulation of the activity of the Gcn2 stress pathway. This mechanism is conserved in yeast and humans. Here, we also show that this family of glutaredoxins, Grx3/Grx4/Glrx3, also has a function related to life extension.
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19
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Alkafeef SS, Lane S, Yu C, Zhou T, Solis NV, Filler SG, Huang L, Liu H. Proteomic profiling of the monothiol glutaredoxin Grx3 reveals its global role in the regulation of iron dependent processes. PLoS Genet 2020; 16:e1008881. [PMID: 32525871 PMCID: PMC7319344 DOI: 10.1371/journal.pgen.1008881] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 06/26/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
Iron is an essential nutrient required as a cofactor for many biological processes. As a fungal commensal-pathogen of humans, Candida albicans encounters a range of bioavailable iron levels in the human host and maintains homeostasis with a conserved regulatory circuit. How C. albicans senses and responds to iron availability is unknown. In model yeasts, regulation of the iron homeostasis circuit requires monothiol glutaredoxins (Grxs), but their functions beyond the regulatory circuit are unclear. Here, we show Grx3 is required for virulence and growth on low iron for C. albicans. To explore the global roles of Grx3, we applied a proteomic approach and performed in vivo cross-linked tandem affinity purification coupled with mass spectrometry. We identified a large number of Grx3 interacting proteins that function in diverse biological processes. This included Fra1 and Bol2/Fra2, which function with Grxs in intracellular iron trafficking in other organisms. Grx3 interacts with and regulates the activity of Sfu1 and Hap43, components of the C. albicans iron regulatory circuit. Unlike the regulatory circuit, which determines expression or repression of target genes in response to iron availability, Grx3 amplifies levels of gene expression or repression. Consistent with the proteomic data, the grx3 mutant is sensitive to heat shock, oxidative, nitrosative, and genotoxic stresses, and shows growth dependence on histidine, leucine, and tryptophan. We suggest Grx3 is a conserved global regulator of iron-dependent processes occurring within the cell. Mammalian pathogens occupy a diverse set of niches within the host organism. These niches vary in iron and oxygen availability. As a commensal and pathogen of humans, its ability to regulate iron uptake and utilization in response to bioavailable iron level is critical for its survival in different host environments encompassing a broad range of iron levels. This study aims to understand how C. albicans senses and responds to iron level to regulate multiple aspects of its biology. The cytosolic monothiol glutaredoxin Grx3 is a critical regulator of C. albicans iron homeostasis and virulence. Taking a proteomic approach, we identified a large list of Grx3 associated proteins of diverse functions, including iron-sulfur trafficking, iron homeostasis, metabolism redox homeostasis, protein translation, DNA maintenance and repair. In support of these protein associations, Grx3 is important for all these processes. Thus, Grx3 is a global regulator of iron homeostasis and other iron dependent cellular processes.
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Affiliation(s)
- Selma S Alkafeef
- Department of Biological Chemistry, University of California, Irvine, California, United States of America.,Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Shelley Lane
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
| | - Clinton Yu
- Department of Physiology & Biophysics, University of California, Irvine, California, United States of America
| | - Tingting Zhou
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
| | - Norma V Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Scott G Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America.,David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Lan Huang
- Department of Physiology & Biophysics, University of California, Irvine, California, United States of America
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
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20
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Jordá T, Romero AM, Perea-García A, Rozès N, Puig S. The lipid composition of yeast cells modulates the response to iron deficiency. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158707. [PMID: 32251724 DOI: 10.1016/j.bbalip.2020.158707] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 01/19/2023]
Abstract
Iron is a vital micronutrient for all eukaryotes because it participates as a redox cofactor in multiple metabolic pathways, including lipid biosynthesis. In response to iron deficiency, the Saccharomyces cerevisiae iron-responsive transcription factor Aft1 accumulates in the nucleus and activates a set of genes that promote iron acquisition at the cell surface. In this study, we report that yeast cells lacking the transcription factor Mga2, which promotes the expression of the iron-dependent Δ9-fatty acid desaturase Ole1, display a defect in the activation of the iron regulon during the adaptation to iron limitation. Supplementation with exogenous unsaturated fatty acids (UFAs) or OLE1 expression rescues the iron regulon activation defect of mga2Δ cells. These observations and fatty acid measurements suggest that the mga2Δ defect in iron regulon expression is due to low UFA levels. Subcellular localization studies reveal that low UFAs cause a mislocalization of Aft1 protein to the vacuole upon iron deprivation that prevents its nuclear accumulation. These results indicate that Mga2 and Ole1 are essential to maintain the UFA levels required for Aft1-dependent activation of the iron regulon in response to iron deficiency, and directly connect the biosynthesis of fatty acids to the response to iron depletion.
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Affiliation(s)
- Tania Jordá
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), , Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Antonia María Romero
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), , Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Ana Perea-García
- 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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21
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Gupta M, Outten CE. Iron-sulfur cluster signaling: The common thread in fungal iron regulation. Curr Opin Chem Biol 2020; 55:189-201. [PMID: 32234663 DOI: 10.1016/j.cbpa.2020.02.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/02/2020] [Accepted: 02/20/2020] [Indexed: 02/07/2023]
Abstract
Iron homeostasis in fungi involves balancing iron uptake and storage with iron utilization to achieve adequate, nontoxic levels of this essential nutrient. Extensive work in the nonpathogenic yeast Saccharomyces cerevisiae and Schizosaccharomyces pombe has uncovered unique iron regulation networks for each organism that control iron metabolism via distinct molecular mechanisms. However, common themes have emerged from these studies. The activities of all fungal iron-sensing transcription factors characterized to date are regulated via iron-sulfur cluster signaling. Furthermore, glutaredoxins often play a key role in relaying the intracellular iron status to these DNA-binding proteins. Recent work with fungal pathogens, including Candida and Aspergillus species and Cryptococcus neoformans, has revealed novel iron regulation mechanisms, yet similar roles for iron-sulfur clusters and glutaredoxins in iron signaling have been confirmed. This review will focus on these recent discoveries regarding iron regulation pathways in both pathogenic and nonpathogenic fungi.
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Affiliation(s)
- Malini Gupta
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA 29208
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA 29208.
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22
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The yeast Aft1 transcription factor activates ribonucleotide reductase catalytic subunit RNR1 in response to iron deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194522. [PMID: 32147528 DOI: 10.1016/j.bbagrm.2020.194522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/25/2020] [Accepted: 03/01/2020] [Indexed: 12/18/2022]
Abstract
Eukaryotic ribonucleotide reductases are iron-dependent enzymes that catalyze the rate-limiting step in the de novo synthesis of deoxyribonucleotides. Multiple mechanisms regulate the activity of ribonucleotide reductases in response to genotoxic stresses and iron deficiency. Upon iron starvation, the Saccharomyces cerevisiae Aft1 transcription factor specifically binds to iron-responsive cis elements within the promoter of a group of genes, known as the iron regulon, activating their transcription. Members of the iron regulon participate in iron acquisition, mobilization and recycling, and trigger a genome-wide metabolic remodeling of iron-dependent pathways. Here, we describe a mechanism that optimizes the activity of yeast ribonucleotide reductase when iron is scarce. We demonstrate that Aft1 and the DNA-binding protein Ixr1 enhance the expression of the gene encoding for its catalytic subunit, RNR1, in response to iron limitation, leading to an increase in both mRNA and protein levels. By mutagenesis of the Aft1-binding sites within RNR1 promoter, we conclude that RNR1 activation by iron depletion is important for Rnr1 protein and deoxyribonucleotide synthesis. Remarkably, Aft1 also activates the expression of IXR1 upon iron scarcity through an iron-responsive element located within its promoter. These results provide a novel mechanism for the direct activation of ribonucleotide reductase function by the iron-regulated Aft1 transcription factor.
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23
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Wang Z, Ma T, Huang Y, Wang J, Chen Y, Kistler HC, Ma Z, Yin Y. A fungal ABC transporter FgAtm1 regulates iron homeostasis via the transcription factor cascade FgAreA-HapX. PLoS Pathog 2019; 15:e1007791. [PMID: 31545842 PMCID: PMC6788720 DOI: 10.1371/journal.ppat.1007791] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/11/2019] [Accepted: 08/05/2019] [Indexed: 02/07/2023] Open
Abstract
Iron homeostasis is important for growth, reproduction and other metabolic processes in all eukaryotes. However, the functions of ATP-binding cassette (ABC) transporters in iron homeostasis are largely unknown. Here, we found that one ABC transporter (named FgAtm1) is involved in regulating iron homeostasis, by screening sensitivity to iron stress for 60 ABC transporter mutants of Fusarium graminearum, a devastating fungal pathogen of small grain cereal crops worldwide. The lack of FgAtm1 reduces the activity of cytosolic Fe-S proteins nitrite reductase and xanthine dehydrogenase, which causes high expression of FgHapX via activating transcription factor FgAreA. FgHapX represses transcription of genes for iron-consuming proteins directly but activates genes for iron acquisition proteins by suppressing another iron regulator FgSreA. In addition, the transcriptional activity of FgHapX is regulated by the monothiol glutaredoxin FgGrx4. Furthermore, the phosphorylation of FgHapX, mediated by the Ser/Thr kinase FgYak1, is required for its functions in iron homeostasis. Taken together, this study uncovers a novel regulatory mechanism of iron homeostasis mediated by an ABC transporter in an important pathogenic fungus. Essential element iron plays important roles in many cellular processes in all organisms. The function of an ATP-binding cassette (ABC) transporter Atm1 in iron homeostasis has been characterized in Saccharomyces cerevisiae. Our study found that FgAtm1 regulates iron homeostasis via the transcription factor cascade FgAreA-HapX in F. graminearum and the function of FgHapX is dependent on its interaction with FgGrx4 and phosphorylation by the Ser/Thr kinase FgYak1. This study reveals a novel regulatory mechanism of iron homeostasis in an important plant pathogenic fungus, and advances our understanding in iron homeostasis and functions of ABC transporters in eukaryotes.
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Affiliation(s)
- Zhihui Wang
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Tianling Ma
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Yunyan Huang
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Jing Wang
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - H. Corby Kistler
- United States Department of Agriculture, Agricultural Research Service, St. Paul, Minnesota, United States of America
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
- * E-mail: (ZM); (YY)
| | - Yanni Yin
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, China
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
- * E-mail: (ZM); (YY)
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24
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Li H, Outten CE. The conserved CDC motif in the yeast iron regulator Aft2 mediates iron-sulfur cluster exchange and protein-protein interactions with Grx3 and Bol2. J Biol Inorg Chem 2019; 24:809-815. [PMID: 31493153 DOI: 10.1007/s00775-019-01705-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/20/2019] [Indexed: 10/26/2022]
Abstract
The Saccharomyces cerevisiae transcriptional activator Aft1 and its paralog Aft2 respond to iron deficiency by upregulating expression of proteins required for iron uptake at the plasma membrane, vacuolar iron transport, and mitochondrial iron metabolism, with the net result of mobilizing iron from extracellular sources and intracellular stores. Conversely, when iron levels are sufficient, Aft1 and Aft2 interact with the cytosolic glutaredoxins Grx3 and Grx4 and the BolA protein Bol2, which promote Aft1/2 dissociation from DNA and subsequent export from the nucleus. Previous studies unveiled the molecular mechanism for iron-dependent inhibition of Aft1/2 activity, demonstrating that the [2Fe-2S]-bridged Grx3-Bol2 heterodimer transfers a cluster to Aft2, driving Aft2 dimerization and dissociation from DNA. Here, we provide further insight into the regulation mechanism by investigating the roles of conserved cysteines in Aft2 in iron-sulfur cluster binding and interaction with [2Fe-2S]-Grx3-Bol2. Using size exclusion chromatography and circular dichroism spectroscopy, these studies reveal that both cysteines in the conserved Aft2 Cys-Asp-Cys motif are essential for Aft2 dimerization via [2Fe-2S] cluster binding, while only one cysteine is required for interaction with the [2Fe-2S]-Grx3-Bol2 complex. Taken together, these results provide novel insight into the molecular details of iron-sulfur cluster transfer from Grx3-Bol2 to Aft2 which likely occurs through a ligand exchange mechanism. Loss of either cysteine in the Aft2 iron-sulfur binding site may disrupt this ligand-exchange process leading to the isolation of a trapped Aft2-Grx3-Bol2 intermediate, while the replacement of both cysteines abrogates both the iron-sulfur cluster exchange and the protein-protein interactions between Aft2 and Grx3-Bol2.
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Affiliation(s)
- Haoran Li
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.,Kymera Therapeutics, Cambridge, MA, 02139, USA
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
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Ramos-Alonso L, Wittmaack N, Mulet I, Martínez-Garay CA, Fita-Torró J, Lozano MJ, Romero AM, García-Ferris C, Martínez-Pastor MT, Puig S. Molecular strategies to increase yeast iron accumulation and resistance. Metallomics 2019; 10:1245-1256. [PMID: 30137082 DOI: 10.1039/c8mt00124c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
All eukaryotic organisms rely on iron as an essential micronutrient for life because it participates as a redox-active cofactor in multiple biological processes. However, excess iron can generate reactive oxygen species that damage cellular macromolecules. The low solubility of ferric iron under physiological conditions increases the prevalence of iron deficiency anemia. A common strategy to treat iron deficiency consists of dietary iron supplementation. The baker's yeast Saccharomyces cerevisiae is used as a model eukaryotic organism, but also as a feed supplement. In response to iron deficiency, the yeast Aft1 transcription factor activates cellular iron acquisition. However, when constitutively active, Aft1 inhibits growth probably due to iron toxicity. In this report, we have studied the consequences of using hyperactive AFT1 alleles, including AFT1-1UP, to increase yeast iron accumulation. We first characterized the iron sensitivity of cells expressing different constitutively active AFT1 alleles. We rescued the high iron sensitivity conferred by the AFT1 alleles by deleting the sphingolipid signaling kinase YPK1. We observed that the deletion of YPK1 exerts different effects on iron accumulation depending on the AFT1 allele and the environmental iron. Moreover, we determined that the impairment of the high-affinity iron transport system partially rescues the high iron toxicity of AFT1-1UP-expressing cells. Finally, we observed that AFT1-1UP inhibits oxygen consumption through activation of the RNA-binding protein Cth2. Deletion of CTH2 partially rescues the AFT1-1UP negative respiratory effect. Collectively, these results contribute to understand how the Aft1 transcription factor functions and the multiple consequences derived from its constitutive activation.
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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), Paterna, Valencia, Spain.
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Do E, Park S, Li MH, Wang JM, Ding C, Kronstad JW, Jung WH. The mitochondrial ABC transporter Atm1 plays a role in iron metabolism and virulence in the human fungal pathogen Cryptococcus neoformans. Med Mycol 2019; 56:458-468. [PMID: 29420779 DOI: 10.1093/mmy/myx073] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/17/2017] [Indexed: 12/19/2022] Open
Abstract
Iron-sulfur clusters (ISC) are indispensable cofactors for essential enzymes in various cellular processes. In the model yeast Saccharomyces cerevisiae, the precursor of ISCs is exported from mitochondria via a mitochondrial ABC transporter Atm1 and used for cytosolic and nuclear ISC protein assembly. Although iron homeostasis has been implicated in the virulence of the human fungal pathogen Cryptococcus neoformans, the key components of the ISC biosynthesis pathway need to be fully elucidated. In the current study, a homolog of S. cerevisiae Atm1 was identified in C. neoformans, and its function was characterized. We constructed C. neoformans mutants lacking ATM1 and found that deletion of ATM1 affected mitochondrial functions. Furthermore, we observed diminished activity of the cytosolic ISC-containing protein Leu1 and the heme-containing protein catalase in the atm1 mutant. These results suggested that Atm1 is required for the biosynthesis of ISCs in the cytoplasm as well as heme metabolism in C. neoformans. In addition, the atm1 mutants were avirulent in a murine model of cryptococcosis. Overall, our results demonstrated that Atm1 plays a critical role in iron metabolism and virulence for C. neoformans.
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Affiliation(s)
- Eunsoo Do
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
| | - Seho Park
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
| | - Ming-Hui Li
- College of Life and Health Sciences, Northeastern University, Shenyang, Liaoning 110015, China
| | - Jia-Mei Wang
- College of Life and Health Sciences, Northeastern University, Shenyang, Liaoning 110015, China
| | - Chen Ding
- College of Life and Health Sciences, Northeastern University, Shenyang, Liaoning 110015, China
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
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Devaux F, Thiébaut A. The regulation of iron homeostasis in the fungal human pathogen Candida glabrata. MICROBIOLOGY-SGM 2019; 165:1041-1060. [PMID: 31050635 DOI: 10.1099/mic.0.000807] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Iron is an essential element to most microorganisms, yet an excess of iron is toxic. Hence, living cells have to maintain a tight balance between iron uptake and iron consumption and storage. The control of intracellular iron concentrations is particularly challenging for pathogens because mammalian organisms have evolved sophisticated high-affinity systems to sequester iron from microbes and because iron availability fluctuates among the different host niches. In this review, we present the current understanding of iron homeostasis and its regulation in the fungal pathogen Candida glabrata. This yeast is an emerging pathogen which has become the second leading cause of candidemia, a life-threatening invasive mycosis. C. glabrata is relatively poorly studied compared to the closely related model yeast Saccharomyces cerevisiae or to the pathogenic yeast Candida albicans. Still, several research groups have started to identify the actors of C. glabrata iron homeostasis and its transcriptional and post-transcriptional regulation. These studies have revealed interesting particularities of C. glabrata and have shed new light on the evolution of fungal iron homeostasis.
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Affiliation(s)
- Frédéric Devaux
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005, Paris, France
| | - Antonin Thiébaut
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005, Paris, France
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Daghino S, Di Vietro L, Petiti L, Martino E, Dallabona C, Lodi T, Perotto S. Yeast expression of mammalian Onzin and fungal FCR1 suggests ancestral functions of PLAC8 proteins in mitochondrial metabolism and DNA repair. Sci Rep 2019; 9:6629. [PMID: 31036870 PMCID: PMC6488628 DOI: 10.1038/s41598-019-43136-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/11/2019] [Indexed: 01/07/2023] Open
Abstract
The cysteine-rich PLAC8 domain of unknown function occurs in proteins found in most Eukaryotes. PLAC8-proteins play important yet diverse roles in different organisms, such as control of cell proliferation in animals and plants or heavy metal resistance in plants and fungi. Mammalian Onzin can be either pro-proliferative or pro-apoptotic, depending on the cell type, whereas fungal FCR1 confers cadmium tolerance. Despite their different role in different organisms, we hypothesized common ancestral functions linked to the PLAC8 domain. To address this hypothesis, and to investigate the molecular function of the PLAC8 domain, murine Onzin and fungal FCR1 were expressed in the PLAC8-free yeast Saccharomyces cerevisiae. The two PLAC8-proteins localized in the nucleus and induced almost identical phenotypes and transcriptional changes when exposed to cadmium stress. Like FCR1, Onzin also reduced DNA damage and increased cadmium tolerance by a DUN1-dependent pathway. Both proteins activated transcription of ancient mitochondrial pathways such as leucine and Fe-S cluster biosynthesis, known to regulate cell proliferation and DNA repair in yeast. These results strongly suggest a common ancestral function of PLAC8 proteins and open new perspectives to understand the role of the PLAC8 domain in the cellular biology of Eukaryotes.
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Affiliation(s)
- Stefania Daghino
- Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Torino, Italy
| | - Luigi Di Vietro
- Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Torino, Italy.,Department of Biochemistry and Biotechnology, Bayer SAS, centre de recherche "la Dargoire" 14, impasse Pierre Baizet CS 99163, 69263, Lyon, CEDEX 09, France
| | - Luca Petiti
- Italian Institute for Genomic Medicine, via Nizza 52, 10126, Torino, Italy
| | - Elena Martino
- Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Torino, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124, Parma, Italy
| | - Tiziana Lodi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124, Parma, Italy
| | - Silvia Perotto
- Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Torino, Italy.
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Dakik P, Medkour Y, Mohammad K, Titorenko VI. Mechanisms Through Which Some Mitochondria-Generated Metabolites Act as Second Messengers That Are Essential Contributors to the Aging Process in Eukaryotes Across Phyla. Front Physiol 2019; 10:461. [PMID: 31057428 PMCID: PMC6482166 DOI: 10.3389/fphys.2019.00461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/02/2019] [Indexed: 12/21/2022] Open
Abstract
Recent studies have revealed that some low-molecular weight molecules produced in mitochondria are essential contributing factors to aging and aging-associated pathologies in evolutionarily distant eukaryotes. These molecules are intermediates or products of certain metabolic reactions that are activated in mitochondria in response to specific changes in the nutrient, stress, proliferation, or age status of the cell. After being released from mitochondria, these metabolites directly or indirectly change activities of a distinct set of protein sensors that reside in various cellular locations outside of mitochondria. Because these protein sensors control the efficiencies of some pro- or anti-aging cellular processes, such changes in their activities allow to create a pro- or anti-aging cellular pattern. Thus, mitochondria can function as signaling platforms that respond to certain changes in cell stress and physiology by remodeling their metabolism and releasing a specific set of metabolites known as "mitobolites." These mitobolites then define the pace of cellular and organismal aging because they regulate some longevity-defining processes taking place outside of mitochondria. In this review, we discuss recent progress in understanding mechanisms underlying the ability of mitochondria to function as such signaling platforms in aging and aging-associated diseases.
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Rey P, Taupin-Broggini M, Couturier J, Vignols F, Rouhier N. Is There a Role for Glutaredoxins and BOLAs in the Perception of the Cellular Iron Status in Plants? FRONTIERS IN PLANT SCIENCE 2019; 10:712. [PMID: 31231405 PMCID: PMC6558291 DOI: 10.3389/fpls.2019.00712] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/14/2019] [Indexed: 05/12/2023]
Abstract
Glutaredoxins (GRXs) have at least three major identified functions. In apoforms, they exhibit oxidoreductase activity controlling notably protein glutathionylation/deglutathionylation. In holoforms, i.e., iron-sulfur (Fe-S) cluster-bridging forms, they act as maturation factors for the biogenesis of Fe-S proteins or as regulators of iron homeostasis contributing directly or indirectly to the sensing of cellular iron status and/or distribution. The latter functions seem intimately connected with the capacity of specific GRXs to form [2Fe-2S] cluster-bridging homodimeric or heterodimeric complexes with BOLA proteins. In yeast species, both proteins modulate the localization and/or activity of transcription factors regulating genes coding for proteins involved in iron uptake and intracellular sequestration in response notably to iron deficiency. Whereas vertebrate GRX and BOLA isoforms may display similar functions, the involved partner proteins are different. We perform here a critical evaluation of the results supporting the implication of both protein families in similar signaling pathways in plants and provide ideas and experimental strategies to delineate further their functions.
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Affiliation(s)
- Pascal Rey
- Plant Protective Proteins Team, CEA, CNRS, BIAM, Aix-Marseille University, Saint-Paul-lez-Durance, France
| | - Maël Taupin-Broggini
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/Université de Montpellier/SupAgro, Montpellier, France
| | | | - Florence Vignols
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/Université de Montpellier/SupAgro, Montpellier, France
| | - Nicolas Rouhier
- Université de Lorraine, INRA, IAM, Nancy, France
- *Correspondence: Nicolas Rouhier,
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Abstract
The acquisition of iron and the maintenance of iron homeostasis are important aspects of virulence for the pathogenic fungus Cryptococcus neoformans In this study, we characterized the role of the monothiol glutaredoxin Grx4 in iron homeostasis and virulence in C. neoformans Monothiol glutaredoxins are important regulators of iron homeostasis because of their conserved roles in [2Fe-2S] cluster sensing and trafficking. We initially identified Grx4 as a binding partner of Cir1, a master regulator of iron-responsive genes and virulence factor elaboration in C. neoformans We confirmed that Grx4 binds Cir1 and demonstrated that iron repletion promotes the relocalization of Grx4 from the nucleus to the cytoplasm. We also found that a grx4 mutant lacking the GRX domain displayed iron-related phenotypes similar to those of a cir1Δ mutant, including poor growth upon iron deprivation. Importantly, the grx4 mutant was avirulent in mice, a phenotype consistent with observed defects in the key virulence determinants, capsule and melanin, and poor growth at 37°C. A comparative transcriptome analysis of the grx4 mutant and the WT strain under low-iron and iron-replete conditions confirmed a central role for Grx4 in iron homeostasis. Dysregulation of iron-related metabolism was consistent with grx4 mutant phenotypes related to oxidative stress, mitochondrial function, and DNA repair. Overall, the phenotypes of the grx4 mutant lacking the GRX domain and the transcriptome sequencing (RNA-Seq) analysis of the mutant support the hypothesis that Grx4 functions as an iron sensor, in part through an interaction with Cir1, to extensively regulate iron homeostasis.IMPORTANCE Fungal pathogens cause life-threatening diseases in humans, particularly in immunocompromised people, and there is a tremendous need for a greater understanding of pathogenesis to support new therapies. One prominent fungal pathogen, Cryptococcus neoformans, causes meningitis in people suffering from HIV/AIDS. In the present study, we focused on characterizing mechanisms by which C. neoformans senses iron availability because iron is both a signal and a key nutrient for proliferation of the pathogen in vertebrate hosts. Specifically, we characterized a monothiol glutaredoxin protein, Grx4, that functions as a sensor of iron availability and interacts with regulatory factors to control the ability of C. neoformans to cause disease. Grx4 regulates key virulence factors, and a mutant is unable to cause disease in a mouse model of cryptococcosis. Overall, our study provides new insights into nutrient sensing and the role of iron in the pathogenesis of fungal diseases.
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Martins TS, Costa V, Pereira C. Signaling pathways governing iron homeostasis in budding yeast. Mol Microbiol 2018; 109:422-432. [DOI: 10.1111/mmi.14009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Telma S. Martins
- I3S-Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC-Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Vítor Costa
- I3S-Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC-Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto; Porto Portugal
| | - Clara Pereira
- I3S-Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC-Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto; Porto Portugal
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The Gcn2-eIF2α pathway connects iron and amino acid homeostasis in Saccharomyces cerevisiae. Biochem J 2018; 475:1523-1534. [PMID: 29626156 DOI: 10.1042/bcj20170871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 04/01/2018] [Accepted: 04/03/2018] [Indexed: 01/02/2023]
Abstract
In eukaryotic cells, amino acid biosynthesis is feedback-inhibited by amino acids through inhibition of the conserved protein kinase Gcn2. This decreases phosphorylation of initiation factor eIF2α, resulting in general activation of translation but inhibition of translation of mRNA for transcription factor (TF) Gcn4 in yeast or ATF4 in mammals. These TFs are positive regulators of amino acid biosynthetic genes. As several enzymes of amino acid biosynthesis contain iron-sulfur clusters (ISCs) and iron excess is toxic, iron and amino acid homeostasis should be co-ordinated. Working with the yeast Saccharomyces cerevisiae, we found that amino acid supplementation down-regulates expression of genes for iron uptake and decreases intracellular iron content. This cross-regulation requires Aft1, the major TF activated by iron scarcity, as well as Gcn2 and phosphorylatable eIF2α but not Gcn4. A mutant with constitutive activity of Gcn2 (GCN2c ) shows less repression of iron transport genes by amino acids and increased nuclear localization of Aft1 in an iron-poor medium, and increases iron content in this medium. As Aft1 is activated by depletion of mitochondrial ISCs, it is plausible that the Gcn2-eIF2α pathway inhibits the formation of these complexes. Accordingly, the GCN2c mutant has strongly reduced activity of succinate dehydrogenase, an iron-sulfur mitochondrial enzyme, and is unable to grow in media with very low iron or with galactose instead of glucose, conditions where formation of ISCs is specially needed. This mechanism adjusts the uptake of iron to the needs of amino acid biosynthesis and expands the list of Gcn4-independent activities of the Gcn2-eIF2α regulatory system.
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Cardenas-Rodriguez M, Chatzi A, Tokatlidis K. Iron-sulfur clusters: from metals through mitochondria biogenesis to disease. J Biol Inorg Chem 2018; 23:509-520. [PMID: 29511832 PMCID: PMC6006200 DOI: 10.1007/s00775-018-1548-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/22/2018] [Indexed: 01/12/2023]
Abstract
Iron–sulfur clusters are ubiquitous inorganic co-factors that contribute to a wide range of cell pathways including the maintenance of DNA integrity, regulation of gene expression and protein translation, energy production, and antiviral response. Specifically, the iron–sulfur cluster biogenesis pathways include several proteins dedicated to the maturation of apoproteins in different cell compartments. Given the complexity of the biogenesis process itself, the iron–sulfur research area constitutes a very challenging and interesting field with still many unaddressed questions. Mutations or malfunctions affecting the iron–sulfur biogenesis machinery have been linked with an increasing amount of disorders such as Friedreich’s ataxia and various cardiomyopathies. This review aims to recap the recent discoveries both in the yeast and human iron–sulfur cluster arena, covering recent discoveries from chemistry to disease.
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Affiliation(s)
- Mauricio Cardenas-Rodriguez
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Afroditi Chatzi
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Kostas Tokatlidis
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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Benchouaia M, Ripoche H, Sissoko M, Thiébaut A, Merhej J, Delaveau T, Fasseu L, Benaissa S, Lorieux G, Jourdren L, Le Crom S, Lelandais G, Corel E, Devaux F. Comparative Transcriptomics Highlights New Features of the Iron Starvation Response in the Human Pathogen Candida glabrata. Front Microbiol 2018; 9:2689. [PMID: 30505294 PMCID: PMC6250833 DOI: 10.3389/fmicb.2018.02689] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/22/2018] [Indexed: 11/21/2022] Open
Abstract
In this work, we used comparative transcriptomics to identify regulatory outliers (ROs) in the human pathogen Candida glabrata. ROs are genes that have very different expression patterns compared to their orthologs in other species. From comparative transcriptome analyses of the response of eight yeast species to toxic doses of selenite, a pleiotropic stress inducer, we identified 38 ROs in C. glabrata. Using transcriptome analyses of C. glabrata response to five different stresses, we pointed out five ROs which were more particularly responsive to iron starvation, a process which is very important for C. glabrata virulence. Global chromatin Immunoprecipitation and gene profiling analyses showed that four of these genes are actually new targets of the iron starvation responsive Aft2 transcription factor in C. glabrata. Two of them (HBS1 and DOM34b) are required for C. glabrata optimal growth in iron limited conditions. In S. cerevisiae, the orthologs of these two genes are involved in ribosome rescue by the NO GO decay (NGD) pathway. Hence, our results suggest a specific contribution of NGD co-factors to the C. glabrata adaptation to iron starvation.
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Affiliation(s)
- Médine Benchouaia
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Hugues Ripoche
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Mariam Sissoko
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Antonin Thiébaut
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Jawad Merhej
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Thierry Delaveau
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Laure Fasseu
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Sabrina Benaissa
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Geneviève Lorieux
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Laurent Jourdren
- École Normale Supérieure, PSL Research University, CNRS, Inserm U1024, Institut de Biologie de l’École Normale Supérieure, Plateforme Génomique, Paris, France
| | - Stéphane Le Crom
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7138, Évolution, Paris, France
| | - Gaëlle Lelandais
- UMR 9198, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, UPSay, Gif-sur-Yvette, France
| | - Eduardo Corel
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7138, Évolution, Paris, France
| | - Frédéric Devaux
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
- *Correspondence: Frédéric Devaux,
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Gerwien F, Skrahina V, Kasper L, Hube B, Brunke S. Metals in fungal virulence. FEMS Microbiol Rev 2018; 42:4562650. [PMID: 29069482 PMCID: PMC5812535 DOI: 10.1093/femsre/fux050] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/19/2017] [Indexed: 12/25/2022] Open
Abstract
Metals are essential for life, and they play a central role in the struggle between infecting microbes and their hosts. In fact, an important aspect of microbial pathogenesis is the 'nutritional immunity', in which metals are actively restricted (or, in an extended definition of the term, locally enriched) by the host to hinder microbial growth and virulence. Consequently, fungi have evolved often complex regulatory networks, uptake and detoxification systems for essential metals such as iron, zinc, copper, nickel and manganese. These systems often differ fundamentally from their bacterial counterparts, but even within the fungal pathogens we can find common and unique solutions to maintain metal homeostasis. Thus, we here compare the common and species-specific mechanisms used for different metals among different fungal species-focusing on important human pathogens such as Candida albicans, Aspergillus fumigatus or Cryptococcus neoformans, but also looking at model fungi such as Saccharomyces cerevisiae or A. nidulans as well-studied examples for the underlying principles. These direct comparisons of our current knowledge reveal that we have a good understanding how model fungal pathogens take up iron or zinc, but that much is still to learn about other metals and specific adaptations of individual species-not the least to exploit this knowledge for new antifungal strategies.
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Affiliation(s)
- Franziska Gerwien
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Volha Skrahina
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Lydia Kasper
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Sascha Brunke
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
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Martins TS, Pereira C, Canadell D, Vilaça R, Teixeira V, Moradas-Ferreira P, de Nadal E, Posas F, Costa V. The Hog1p kinase regulates Aft1p transcription factor to control iron accumulation. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:61-70. [DOI: 10.1016/j.bbalip.2017.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/15/2017] [Accepted: 10/09/2017] [Indexed: 12/22/2022]
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Abstract
SIGNIFICANCE Glutathione (GSH) is the most abundant cellular low-molecular-weight thiol in the majority of organisms in all kingdoms of life. Therefore, functions of GSH and disturbed regulation of its concentration are associated with numerous physiological and pathological situations. Recent Advances: The function of GSH as redox buffer or antioxidant is increasingly being questioned. New functions, especially functions connected to the cellular iron homeostasis, were elucidated. Via the formation of iron complexes, GSH is an important player in all aspects of iron metabolism: sensing and regulation of iron levels, iron trafficking, and biosynthesis of iron cofactors. The variety of GSH coordinated iron complexes and their functions with a special focus on FeS-glutaredoxins are summarized in this review. Interestingly, GSH analogues that function as major low-molecular-weight thiols in organisms lacking GSH resemble the functions in iron homeostasis. CRITICAL ISSUES Since these iron-related functions are most likely also connected to thiol redox chemistry, it is difficult to distinguish between mechanisms related to either redox or iron metabolisms. FUTURE DIRECTIONS The ability of GSH to coordinate iron in different complexes with or without proteins needs further investigation. The discovery of new Fe-GSH complexes and their physiological functions will significantly advance our understanding of cellular iron homeostasis. Antioxid. Redox Signal. 27, 1235-1251.
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Affiliation(s)
- Carsten Berndt
- 1 Department of Neurology, Medical Faculty, Life Science Center , Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Christopher Horst Lillig
- 2 Institute for Medical Biochemistry and Molecular Biology, University Medicine Greifswald , Greifswald, Germany
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Diament A, Tuller T. Tracking the evolution of 3D gene organization demonstrates its connection to phenotypic divergence. Nucleic Acids Res 2017; 45:4330-4343. [PMID: 28369658 PMCID: PMC5416853 DOI: 10.1093/nar/gkx205] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/20/2017] [Indexed: 12/20/2022] Open
Abstract
It has recently been shown that the organization of genes in eukaryotic genomes, and specifically in 3D, is strongly related to gene expression and function and partially conserved between organisms. However, previous studies of 3D genomic organization analyzed each organism independently from others. Here, we propose an approach for unified inter-organismal analysis of gene organization based on a network representation of Hi-C data. We define and detect four classes of spatially co-evolving orthologous modules (SCOMs), i.e. gene families that co-evolve in their 3D organization, based on patterns of divergence and conservation of distances. We demonstrate our methodology on Hi-C data from Saccharomyces cerevisiae and Schizosaccharomyces pombe, and identify, among others, modules relating to RNA splicing machinery and chromatin silencing by small RNA which are central to S. pombe's lifestyle. Our results emphasize the importance of 3D genomic organization in eukaryotes and suggest that the evolutionary mechanisms that shape gene organization affect the organism fitness and phenotypes. The proposed algorithms can be utilized in future studies of genome evolution and comparative analysis of spatial genomic organization in different tissues, conditions and single cells.
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Affiliation(s)
- Alon Diament
- Biomedical Engineering Dept., Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tamir Tuller
- Biomedical Engineering Dept., Tel Aviv University, Tel Aviv 6997801, Israel.,The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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40
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Mechanisms of iron sensing and regulation in the yeast Saccharomyces cerevisiae. World J Microbiol Biotechnol 2017; 33:75. [DOI: 10.1007/s11274-017-2215-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/18/2017] [Indexed: 01/11/2023]
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41
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Pujol-Carrion N, Torre-Ruiz MADL. Physical interaction between the MAPK Slt2 of the PKC1-MAPK pathway and Grx3/Grx4 glutaredoxins is required for the oxidative stress response in budding yeast. Free Radic Biol Med 2017; 103:107-120. [PMID: 28007574 DOI: 10.1016/j.freeradbiomed.2016.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 12/02/2016] [Accepted: 12/18/2016] [Indexed: 01/20/2023]
Abstract
This study demonstrates that both monothiol glutaredoxins Grx3 and Grx4 physically interact with the MAPK Slt2 forming a complex involved in the cellular response to oxidative stress. The simultaneous absence of Grx3 and Grx4 provokes a serious impairment in cell viability, Slt2 activation and Rlm1 transcription in response to oxidative stress. Both in vivo and in vitro results clearly show that Slt2 can independently bind either Grx3 or Grx4 proteins. Our results suggest that Slt2 form iron/sulphur bridged clusters with Grx3 and Grx4. For the assembly of this complex, cysteines of the active site of each Grx3/4 glutaredoxins, glutathione and specific cysteine residues from Slt2 provide the ligands. One of the ligands of Slt2 is required for its dimerisation upon oxidative treatment and iron repletion. These interactions are relevant for the oxidative response, given that mutants in the cysteine ligands identified in the complex show a severe impairment of both cell viability and Slt2 phosphorylation upon oxidative stress. Grx4 is the relevant glutaredoxin that regulates Slt2 phosphorylation under oxidative conditions precluding cell survival. Our studies contribute to extend the functions of both monothiol glutaredoxins to the regulation of a MAPK in the context of the oxidative stress response.
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Affiliation(s)
- Nuria Pujol-Carrion
- Department of Basic Medical Sciences, IRB-Lleida. University of Lleida, Av. Alcalde Rovira Roure no 80, 25198 Lleida, Spain
| | - Maria Angeles de la Torre-Ruiz
- Department of Basic Medical Sciences, IRB-Lleida. University of Lleida, Av. Alcalde Rovira Roure no 80, 25198 Lleida, Spain.
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42
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Dlouhy AC, Li H, Albetel AN, Zhang B, Mapolelo DT, Randeniya S, Holland AA, Johnson MK, Outten CE. The Escherichia coli BolA Protein IbaG Forms a Histidine-Ligated [2Fe-2S]-Bridged Complex with Grx4. Biochemistry 2016; 55:6869-6879. [PMID: 27951647 DOI: 10.1021/acs.biochem.6b00812] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Two ubiquitous protein families have emerged as key players in iron metabolism, the CGFS-type monothiol glutaredoxins (Grxs) and the BolA proteins. Monothiol Grxs and BolA proteins form heterocomplexes that have been implicated in Fe-S cluster assembly and trafficking. The Escherichia coli genome encodes members of both of these proteins families, namely, the monothiol glutaredoxin Grx4 and two BolA family proteins, BolA and IbaG. Previous work has demonstrated that E. coli Grx4 and BolA interact as both apo and [2Fe-2S]-bridged heterodimers that are spectroscopically distinct from [2Fe-2S]-bridged Grx4 homodimers. However, the physical and functional interactions between Grx4 and IbaG are uncharacterized. Here we show that co-expression of Grx4 with IbaG yields a [2Fe-2S]-bridged Grx4-IbaG heterodimer. In vitro interaction studies indicate that IbaG binds the [2Fe-2S] Grx4 homodimer to form apo Grx4-IbaG heterodimer as well as the [2Fe-2S] Grx4-IbaG heterodimer, altering the cluster stability and coordination environment. Additionally, spectroscopic and mutagenesis studies provide evidence that IbaG ligates the Fe-S cluster via the conserved histidine that is present in all BolA proteins and by a second conserved histidine that is present in the H/C loop of two of the four classes of BolA proteins. These results suggest that IbaG may function in Fe-S cluster assembly and trafficking in E. coli as demonstrated for other BolA homologues that interact with monothiol Grxs.
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Affiliation(s)
- Adrienne C Dlouhy
- Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Haoran Li
- Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Angela-Nadia Albetel
- Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Bo Zhang
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Daphne T Mapolelo
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Sajini Randeniya
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Ashley A Holland
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Michael K Johnson
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina , 631 Sumter Street, Columbia, South Carolina 29208, United States
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43
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A Novel Hybrid Iron Regulation Network Combines Features from Pathogenic and Nonpathogenic Yeasts. mBio 2016; 7:mBio.01782-16. [PMID: 27795405 PMCID: PMC5082906 DOI: 10.1128/mbio.01782-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Iron is an essential micronutrient for both pathogens and their hosts, which restrict iron availability during infections in an effort to prevent microbial growth. Successful human pathogens like the yeast Candida glabrata have thus developed effective iron acquisition strategies. Their regulation has been investigated well for some pathogenic fungi and in the model organism Saccharomyces cerevisiae, which employs an evolutionarily derived system. Here, we show that C. glabrata uses a regulation network largely consisting of components of the S. cerevisiae regulon but also of elements of other pathogenic fungi. Specifically, similarly to baker's yeast, Aft1 is the main positive regulator under iron starvation conditions, while Cth2 degrades mRNAs encoding iron-requiring enzymes. However, unlike the case with S. cerevisiae, a Sef1 ortholog is required for full growth under iron limitation conditions, making C. glabrata an evolutionary intermediate to SEF1-dependent fungal pathogens. Therefore, C. glabrata has evolved an iron homeostasis system which seems to be unique within the pathogenic fungi. IMPORTANCE The fungus Candida glabrata represents an evolutionarily close relative of the well-studied and benign baker's yeast and model organism Saccharomyces cerevisiae On the other hand, C. glabrata is an important opportunistic human pathogen causing both superficial and systemic infections. The ability to acquire trace metals, in particular, iron, and to tightly regulate this process during infection is considered an important virulence attribute of a variety of pathogens. Importantly, S. cerevisiae uses a highly derivative regulatory system distinct from those of other fungi. Until now, the regulatory mechanism of iron homeostasis in C. glabrata has been mostly unknown. Our study revealed a hybrid iron regulation network that is unique to C. glabrata and is placed at an evolutionary midpoint between those of S. cerevisiae and related fungal pathogens. We thereby show that, in the host, even a successful human pathogen can rely largely on a strategy normally found in nonpathogenic fungi from a terrestrial environment.
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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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45
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Merhej J, Thiebaut A, Blugeon C, Pouch J, Ali Chaouche MEA, Camadro JM, Le Crom S, Lelandais G, Devaux F. A Network of Paralogous Stress Response Transcription Factors in the Human Pathogen Candida glabrata. Front Microbiol 2016; 7:645. [PMID: 27242683 PMCID: PMC4860858 DOI: 10.3389/fmicb.2016.00645] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 04/18/2016] [Indexed: 01/15/2023] Open
Abstract
The yeast Candida glabrata has become the second cause of systemic candidemia in humans. However, relatively few genome-wide studies have been conducted in this organism and our knowledge of its transcriptional regulatory network is quite limited. In the present work, we combined genome-wide chromatin immunoprecipitation (ChIP-seq), transcriptome analyses, and DNA binding motif predictions to describe the regulatory interactions of the seven Yap (Yeast AP1) transcription factors of C. glabrata. We described a transcriptional network containing 255 regulatory interactions and 309 potential target genes. We predicted with high confidence the preferred DNA binding sites for 5 of the 7 CgYaps and showed a strong conservation of the Yap DNA binding properties between S. cerevisiae and C. glabrata. We provided reliable functional annotation for 3 of the 7 Yaps and identified for Yap1 and Yap5 a core regulon which is conserved in S. cerevisiae, C. glabrata, and C. albicans. We uncovered new roles for CgYap7 in the regulation of iron-sulfur cluster biogenesis, for CgYap1 in the regulation of heme biosynthesis and for CgYap5 in the repression of GRX4 in response to iron starvation. These transcription factors define an interconnected transcriptional network at the cross-roads between redox homeostasis, oxygen consumption, and iron metabolism.
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Affiliation(s)
- Jawad Merhej
- Laboratoire de Biologie Computationnelle et Quantitative, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, UMR 7238, Sorbonne Universités, Université Pierre et Marie Curie Paris, France
| | - Antonin Thiebaut
- Laboratoire de Biologie Computationnelle et Quantitative, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, UMR 7238, Sorbonne Universités, Université Pierre et Marie Curie Paris, France
| | - Corinne Blugeon
- École Normale Supérieure, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institut de Biologie de l'École Normale Supérieure, Plateforme Génomique Paris, France
| | - Juliette Pouch
- École Normale Supérieure, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institut de Biologie de l'École Normale Supérieure, Plateforme Génomique Paris, France
| | - Mohammed El Amine Ali Chaouche
- École Normale Supérieure, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institut de Biologie de l'École Normale Supérieure, Plateforme Génomique Paris, France
| | - Jean-Michel Camadro
- Centre National de la Recherche Scientifique, UMR 7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité Paris, France
| | - Stéphane Le Crom
- Évolution, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, UMR 7138, Sorbonne Universités, Université Pierre et Marie Curie Paris, France
| | - Gaëlle Lelandais
- Centre National de la Recherche Scientifique, UMR 7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité Paris, France
| | - Frédéric Devaux
- Laboratoire de Biologie Computationnelle et Quantitative, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, UMR 7238, Sorbonne Universités, Université Pierre et Marie Curie Paris, France
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46
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Hu Z, Wang Y, Yu L, Mahanty SK, Mendoza N, Elion EA. Mapping regions in Ste5 that support Msn5-dependent and -independent nuclear export. Biochem Cell Biol 2016; 94:109-28. [PMID: 26824509 DOI: 10.1139/bcb-2015-0101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Careful control of the available pool of the MAPK scaffold Ste5 is important for mating-pathway activation and the prevention of inappropriate mating differentiation in haploid Saccharomyces cerevisiae. Ste5 shuttles constitutively through the nucleus, where it is degraded by a ubiquitin-dependent mechanism triggered by G1 CDK phosphorylation. Here we narrow-down regions of Ste5 that mediate nuclear export. Four regions in Ste5 relocalize SV40-TAgNLS-GFP-GFP from nucleus to cytoplasm. One region is N-terminal, dependent on exportin Msn5/Ste21/Kap142, and interacts with Msn5 in 2 hybrid assays independently of mating pheromone, Fus3, Kss1, Ptc1, the NLS/PM, and RING-H2. A second region overlaps the PH domain and Ste11 binding site and 2 others are on the vWA domain and include residues essential for MAPK activation. We find no evidence for dependence on Crm1/Xpo1, despite numerous potential nuclear export sequences (NESs) detected by LocNES and NetNES1.1 predictors. Thus, Msn5 (homolog of human Exportin-5) and one or more exportins or adaptor molecules besides Crm1/Xpo1 may regulate Ste5 through multiple recognition sites.
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Affiliation(s)
- Zhenhua Hu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Yunmei Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Lu Yu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sanjoy K Mahanty
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Natalia Mendoza
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Elaine A Elion
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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47
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Vigani G, Briat JF. Impairment of Respiratory Chain under Nutrient Deficiency in Plants: Does it Play a Role in the Regulation of Iron and Sulfur Responsive Genes? FRONTIERS IN PLANT SCIENCE 2016; 6:1185. [PMID: 26779219 PMCID: PMC4700279 DOI: 10.3389/fpls.2015.01185] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/10/2015] [Indexed: 05/23/2023]
Abstract
Plant production and plant product quality strongly depend on the availability of mineral nutrients. Among them, sulfur (S) and iron (Fe) play a central role, as they are needed for many proteins of the respiratory chain. Plant mitochondria play essential bioenergetic and biosynthetic functions as well as they have an important role in signaling processes into the cell. Here, by comparing several transcriptomic data sets from plants impaired in their respiratory function with the genes regulated under Fe or S deficiencies obtained from other data sets, nutrient-responsive genes potentially regulated by hypothetical mitochondrial retrograde signaling pathway are evidenced. It leads us to hypothesize that plant mitochondria could be, therefore, required for regulating the expression of key genes involved both in Fe and S metabolisms.
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Affiliation(s)
- Gianpiero Vigani
- Dipartimento di Scienze Agrarie e Ambientali-Produzione, Territorio Agroenergia, Università degli Studi di MilanoMilan, Italy
| | - Jean-François Briat
- Biochimie and Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/SupAgro/UM2Montpellier, France
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48
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Ozer HK, Dlouhy AC, Thornton JD, Hu J, Liu Y, Barycki JJ, Balk J, Outten CE. Cytosolic Fe-S Cluster Protein Maturation and Iron Regulation Are Independent of the Mitochondrial Erv1/Mia40 Import System. J Biol Chem 2015; 290:27829-40. [PMID: 26396185 DOI: 10.1074/jbc.m115.682179] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Indexed: 01/08/2023] Open
Abstract
The sulfhydryl oxidase Erv1 partners with the oxidoreductase Mia40 to import cysteine-rich proteins in the mitochondrial intermembrane space. In Saccharomyces cerevisiae, Erv1 has also been implicated in cytosolic Fe-S protein maturation and iron regulation. To investigate the connection between Erv1/Mia40-dependent mitochondrial protein import and cytosolic Fe-S cluster assembly, we measured Mia40 oxidation and Fe-S enzyme activities in several erv1 and mia40 mutants. Although all the erv1 and mia40 mutants exhibited defects in Mia40 oxidation, only one erv1 mutant strain (erv1-1) had significantly decreased activities of cytosolic Fe-S enzymes. Further analysis of erv1-1 revealed that it had strongly decreased glutathione (GSH) levels, caused by an additional mutation in the gene encoding the glutathione biosynthesis enzyme glutamate cysteine ligase (GSH1). To address whether Erv1 or Mia40 plays a role in iron regulation, we measured iron-dependent expression of Aft1/2-regulated genes and mitochondrial iron accumulation in erv1 and mia40 strains. The only strain to exhibit iron misregulation is the GSH-deficient erv1-1 strain, which is rescued with addition of GSH. Together, these results confirm that GSH is critical for cytosolic Fe-S protein biogenesis and iron regulation, whereas ruling out significant roles for Erv1 or Mia40 in these pathways.
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Affiliation(s)
- Hatice K Ozer
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Adrienne C Dlouhy
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Jeremy D Thornton
- the John Innes Centre and University of East Anglia, Norwich Research Park, Norwich NR4 7UH, United Kingdom, and
| | - Jingjing Hu
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Yilin Liu
- the Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588
| | - Joseph J Barycki
- the Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588
| | - Janneke Balk
- the John Innes Centre and University of East Anglia, Norwich Research Park, Norwich NR4 7UH, United Kingdom, and
| | - Caryn E Outten
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208,
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49
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Lill R, Srinivasan V, Mühlenhoff U. The role of mitochondria in cytosolic-nuclear iron–sulfur protein biogenesis and in cellular iron regulation. Curr Opin Microbiol 2015; 22:111-9. [PMID: 25460804 DOI: 10.1016/j.mib.2014.09.015] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/20/2014] [Accepted: 09/24/2014] [Indexed: 12/16/2022]
Abstract
Mitochondria are indispensable in eukaryotes because of their function in the maturation of cytosolic and nuclear iron–sulfur proteins that are essential for DNA synthesis and repair, tRNA modification, and protein translation. The mitochondrial Fe/S cluster assembly machinery not only generates the organelle's iron–sulfur proteins, but also extra-mitochondrial ones. Biogenesis of the latter proteins requires the mitochondrial ABC transporter Atm1 that exports a sulfur-containing compound in a glutathione-dependent fashion. The process is further assisted by the cytosolic iron–sulfur protein assembly machinery. Here, we discuss the knowns and unknowns of the mitochondrial export process that is also crucial for signaling the cellular iron status to the regulatory systems involved in the maintenance of cellular iron homeostasis.
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Affiliation(s)
- Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany.
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50
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Lill R, Dutkiewicz R, Freibert SA, Heidenreich T, Mascarenhas J, Netz DJ, Paul VD, Pierik AJ, Richter N, Stümpfig M, Srinivasan V, Stehling O, Mühlenhoff U. The role of mitochondria and the CIA machinery in the maturation of cytosolic and nuclear iron–sulfur proteins. Eur J Cell Biol 2015; 94:280-91. [DOI: 10.1016/j.ejcb.2015.05.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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