101
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Soares Moretti AI, Martins Laurindo FR. Protein disulfide isomerases: Redox connections in and out of the endoplasmic reticulum. Arch Biochem Biophys 2016; 617:106-119. [PMID: 27889386 DOI: 10.1016/j.abb.2016.11.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/08/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Protein disulfide isomerases are thiol oxidoreductase chaperones from thioredoxin superfamily. As redox folding catalysts from the endoplasmic reticulum (ER), their roles in ER-related redox homeostasis and signaling are well-studied. PDIA1 exerts thiol oxidation/reduction and isomerization, plus chaperone effects. Also, substantial evidence indicates that PDIs regulate thiol-disulfide switches in other cell locations such as cell surface and possibly cytosol. Subcellular PDI translocation routes remain unclear and seem Golgi-independent. The list of signaling and structural proteins reportedly regulated by PDIs keeps growing, via thiol switches involving oxidation, reduction and isomerization, S-(de)nytrosylation, (de)glutathyonylation and protein oligomerization. PDIA1 is required for agonist-triggered Nox NADPH oxidase activation and cell migration in vascular cells and macrophages, while PDIA1-dependent cytoskeletal regulation appears a converging pathway. Extracellularly, PDIs crucially regulate thiol redox signaling of thrombosis/platelet activation, e.g., integrins, and PDIA1 supports expansive caliber remodeling during injury repair via matrix/cytoskeletal organization. Some proteins display regulatory PDI-like motifs. PDI effects are orchestrated by expression levels or post-translational modifications. PDI is redox-sensitive, although probably not a mass-effect redox sensor due to kinetic constraints. Rather, the "all-in-one" organization of its peculiar redox/chaperone properties likely provide PDIs with precision and versatility in redox signaling, making them promising therapeutic targets.
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Affiliation(s)
- Ana Iochabel Soares Moretti
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo, School of Medicine, São Paulo, Brazil
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102
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Eastland A, Hornick J, Kawamura R, Nanavati D, Marko JF. Dependence of the structure and mechanics of metaphase chromosomes on oxidized cysteines. Chromosome Res 2016; 24:339-53. [PMID: 27145786 PMCID: PMC4970972 DOI: 10.1007/s10577-016-9528-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/09/2016] [Accepted: 04/26/2016] [Indexed: 11/28/2022]
Abstract
We have found that reagents that reduce oxidized cysteines lead to destabilization of metaphase chromosome folding, suggesting that chemically linked cysteine residues may play a structural role in mitotic chromosome organization, in accord with classical studies by Dounce et al. (J Theor Biol 42:275-285, 1973) and Sumner (J Cell Sci 70:177-188, 1984a). Human chromosomes isolated into buffer unfold when exposed to dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP). In micromanipulation experiments which allow us to examine the mechanics of individual metaphase chromosomes, we have found that the gel-like elastic stiffness of native metaphase chromosomes is dramatically suppressed by DTT and TCEP, even before the chromosomes become appreciably unfolded. We also report protein labeling experiments on human metaphase chromosomes which allow us to tag oxidized and reduction-sensitive cysteine residues. PAGE analysis using fluorescent labels shows a small number of labeled bands. Mass spectrometry analysis of similarly labeled proteins provides a list of candidates for proteins with oxidized cysteines involved in chromosome organization, notably including components of condensin I, cohesin, the nucleosome-interacting proteins RCC1 and RCC2, as well as the RNA/DNA-binding protein NONO/p54NRB.
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Affiliation(s)
- Adrienne Eastland
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA
| | - Jessica Hornick
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA
| | - Ryo Kawamura
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - Dhaval Nanavati
- Proteomics Core, Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, 60208, USA
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA.
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA.
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103
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Araki K, Kusano H, Sasaki N, Tanaka R, Hatta T, Fukui K, Natsume T. Redox Sensitivities of Global Cellular Cysteine Residues under Reductive and Oxidative Stress. J Proteome Res 2016; 15:2548-59. [DOI: 10.1021/acs.jproteome.6b00087] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kazutaka Araki
- Molecular
Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | - Hidewo Kusano
- Molecular
Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | | | - Riko Tanaka
- Molecular
Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | | | - Kazuhiko Fukui
- Molecular
Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | - Tohru Natsume
- Molecular
Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
- Robotic Biology Institute, Inc., Tokyo 135-0064, Japan
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104
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Barile M, Giancaspero TA, Leone P, Galluccio M, Indiveri C. Riboflavin transport and metabolism in humans. J Inherit Metab Dis 2016; 39:545-57. [PMID: 27271694 DOI: 10.1007/s10545-016-9950-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/12/2016] [Accepted: 05/19/2016] [Indexed: 12/17/2022]
Abstract
Recent studies elucidated how riboflavin transporters and FAD forming enzymes work in humans and create a coordinated flavin network ensuring the maintenance of cellular flavoproteome. Alteration of this network may be causative of severe metabolic disorders such as multiple acyl-CoA dehydrogenase deficiency (MADD) or Brown-Vialetto-van Laere syndrome. A crucial step in the maintenance of FAD homeostasis is riboflavin uptake by plasma and mitochondrial membranes. Therefore, studies on recently identified human plasma membrane riboflavin transporters are presented, together with those in which still unidentified mitochondrial riboflavin transporter(s) have been described. A main goal of future research is to fill the gaps still existing as for some transcriptional, functional and structural details of human FAD synthases (FADS) encoded by FLAD1 gene, a novel "redox sensing" enzyme. In the frame of the hypothesis that FADS, acting as a "FAD chaperone", could play a crucial role in the biogenesis of mitochondrial flavo-proteome, several basic functional aspects of flavin cofactor delivery to cognate apo-flavoenzyme are also briefly dealt with. The establishment of model organisms performing altered FAD homeostasis will improve the molecular description of human pathologies. The molecular and functional studies of transporters and enzymes herereported, provide guidelines for improving therapies which may have beneficial effects on the altered metabolism.
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Affiliation(s)
- Maria Barile
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy.
| | - Teresa Anna Giancaspero
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy
| | - Piero Leone
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", via Orabona 4, I-70126, Bari, Italy
| | - Michele Galluccio
- Dipartimento DiBEST (Biologia, Ecologia, Scienze della Terra), Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Dipartimento DiBEST (Biologia, Ecologia, Scienze della Terra), Unità di Biochimica e Biotecnologie Molecolari, Università della Calabria, via Bucci 4c, I-87036, Arcavacata di Rende, Italy
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105
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Couto N, Wood J, Barber J. The role of glutathione reductase and related enzymes on cellular redox homoeostasis network. Free Radic Biol Med 2016; 95:27-42. [PMID: 26923386 DOI: 10.1016/j.freeradbiomed.2016.02.028] [Citation(s) in RCA: 495] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/19/2016] [Accepted: 02/24/2016] [Indexed: 02/07/2023]
Abstract
In this review article we examine the role of glutathione reductase in the regulation, modulation and maintenance of cellular redox homoeostasis. Glutathione reductase is responsible for maintaining the supply of reduced glutathione; one of the most abundant reducing thiols in the majority of cells. In its reduced form, glutathione plays key roles in the cellular control of reactive oxygen species. Reactive oxygen species act as intracellular and extracellular signalling molecules and complex cross talk between levels of reactive oxygen species, levels of oxidised and reduced glutathione and other thiols, and antioxidant enzymes such as glutathione reductase determine the most suitable conditions for redox control within a cell or for activation of programmed cell death. Additionally, we discuss the translation and expression of glutathione reductase in a number of organisms including yeast and humans. In yeast and human cells, a single gene expresses more than one form of glutathione reductase, destined for residence in the cytoplasm or for translocation to different organelles; in plants, however, two genes encoding this protein have been described. In general, insects and kinetoplastids (a group of protozoa, including Plasmodia and Trypanosoma) do not express glutathione reductase or glutathione biosynthetic enzymes. Instead, they express either the thioredoxin system or the trypanothione system. The thioredoxin system is also present in organisms that have the glutathione system and there may be overlapping functions with cross-talk between the two systems. Finally we evaluate therapeutic targets to overcome oxidative stress associated cellular disorders.
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Affiliation(s)
- Narciso Couto
- Michael Barber Centre for Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Road, Manchester M1 7DN, UK; ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK.
| | - Jennifer Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Jill Barber
- Michael Barber Centre for Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Road, Manchester M1 7DN, UK; Manchester Pharmacy School, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
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106
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Tarasava K, Chesnov S, Freisinger E. Oxidation of the N-terminal domain of the wheat metallothionein Ec -1 leads to the formation of three distinct disulfide bridges. Biopolymers 2016; 106:295-308. [PMID: 27061576 DOI: 10.1002/bip.22849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 04/05/2016] [Indexed: 01/15/2023]
Abstract
Metallothioneins (MTs) are low molecular weight proteins, characterized by a high cysteine content and the ability to coordinate large amounts of d(10) metal ions, for example, Zn(II), Cd(II), and Cu(I), in form of metal-thiolate clusters. Depending on intracellular conditions such as redox potential or metal ion concentrations, MTs can occur in various states ranging from the fully metal-loaded holo- to the metal-free apo-form. The Cys thiolate groups in the apo-form can be either reduced or be involved in disulfide bridges. Although oxidation-mediated Zn(II) release might be a possible mechanism for the regulation of Zn(II) availability by MTs, no concise information regarding the associated pathways and the structure of oxidized apo-MT forms is available. Using the well-studied Zn2 γ-Ec -1 domain of the wheat Zn6 Ec -1 MT we attempt here to answer several question regarding the structure and biophysical properties of oxidized MT forms, such as: (1) does disulfide bond formation increase the stability against proteolysis, (2) is the overall peptide backbone fold similar for the holo- and the oxidized apo-MT form, and (3) are disulfide bridges specifically or randomly formed? Our investigations show that oxidation leads to three distinct disulfide bridges independently of the applied oxidation conditions and of the initial species used for oxidation, that is, the apo- or the holo-form. In addition, the oxidized apo-form is as stable against proteolysis as Zn2 γ-Ec -1, rendering the currently assumed degradation of oxidized MTs unlikely and suggesting a role of the oxidation process for the extension of protein lifetime in absence of sufficient amounts of metal ions. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 295-308, 2016.
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Affiliation(s)
- Katsiaryna Tarasava
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich, 8057, Switzerland
| | - Serge Chesnov
- University of Zurich/ETH Zurich, Functional Genomics Center Zurich, Winterthurerstrasse 190, Zurich, 8057, Switzerland
| | - Eva Freisinger
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich, 8057, Switzerland
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107
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Protein folding alterations in amyotrophic lateral sclerosis. Brain Res 2016; 1648:633-649. [PMID: 27064076 DOI: 10.1016/j.brainres.2016.04.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/04/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Protein misfolding leads to the formation of aggregated proteins and protein inclusions, which are associated with synaptic loss and neuronal death in neurodegenerative diseases. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that targets motor neurons in the brain, brainstem and spinal cord. Several proteins misfold and are associated either genetically or pathologically in ALS, including superoxide dismutase 1 (SOD1), Tar DNA binding protein-43 (TDP-43), Ubiquilin-2, p62, VCP, and dipeptide repeat proteins produced by unconventional repeat associated non-ATG translation of the repeat expansion in C9ORF72. Chaperone proteins, including heat shock proteins (Hsp׳s) and the protein disulphide isomerase (PDI) family, assist in protein folding and therefore can prevent protein misfolding, and have been implicated as being protective in ALS. In this review we provide an overview of the current literature regarding the molecular mechanisms of protein misfolding and aggregation in ALS, and the role of chaperones as potential targets for therapeutic intervention. This article is part of a Special Issue entitled SI:ER stress.
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108
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Konno T, Pinho Melo E, Lopes C, Mehmeti I, Lenzen S, Ron D, Avezov E. ERO1-independent production of H2O2 within the endoplasmic reticulum fuels Prdx4-mediated oxidative protein folding. J Cell Biol 2016; 211:253-9. [PMID: 26504166 PMCID: PMC4621842 DOI: 10.1083/jcb.201506123] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tracking the kinetics of equilibration of H2O2 between compartments reveals unexpected isolation of the endoplasmic reticulum and hints at a hitherto unsuspected local source of peroxide. The endoplasmic reticulum (ER)–localized peroxiredoxin 4 (PRDX4) supports disulfide bond formation in eukaryotic cells lacking endoplasmic reticulum oxidase 1 (ERO1). The source of peroxide that fuels PRDX4-mediated disulfide bond formation has remained a mystery, because ERO1 is believed to be a major producer of hydrogen peroxide (H2O2) in the ER lumen. We report on a simple kinetic technique to track H2O2 equilibration between cellular compartments, suggesting that the ER is relatively isolated from cytosolic or mitochondrial H2O2 pools. Furthermore, expression of an ER-adapted catalase to degrade lumenal H2O2 attenuated PRDX4-mediated disulfide bond formation in cells lacking ERO1, whereas depletion of H2O2 in the cytosol or mitochondria had no similar effect. ER catalase did not effect the slow residual disulfide bond formation in cells lacking both ERO1 and PRDX4. These observations point to exploitation of a hitherto unrecognized lumenal source of H2O2 by PRDX4 and a parallel slow H2O2-independent pathway for disulfide formation.
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Affiliation(s)
- Tasuku Konno
- University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, CB2 0XY, UK
| | - Eduardo Pinho Melo
- Center for Biomedical Research, Universidade do Algarve, Faro, Portugal 8005-139
| | - Carlos Lopes
- Center for Biomedical Research, Universidade do Algarve, Faro, Portugal 8005-139
| | - Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Sigurd Lenzen
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - David Ron
- University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, CB2 0XY, UK
| | - Edward Avezov
- University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, CB2 0XY, UK
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109
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Wu T, Yang C, Ding B, Feng Z, Wang Q, He J, Tong J, Xiao L, Jiang L, Wan J. Microarray-based gene expression analysis of strong seed dormancy in rice cv. N22 and less dormant mutant derivatives. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 99:27-38. [PMID: 26713549 DOI: 10.1016/j.plaphy.2015.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 11/28/2015] [Accepted: 12/01/2015] [Indexed: 05/04/2023]
Abstract
Seed dormancy in rice is an important trait related to the pre-harvest sprouting resistance. In order to understand the molecular mechanisms of seed dormancy, gene expression was investigated by transcriptome analysis using seeds of the strongly dormant cultivar N22 and its less dormant mutants Q4359 and Q4646 at 24 days after heading (DAH). Microarray data revealed more differentially expressed genes in Q4359 than in Q4646 compared to N22. Most genes differing between Q4646 and N22 also differed between Q4359 and N22. GO analysis of genes differentially expressed in both Q4359 and Q4646 revealed that some genes such as those for starch biosynthesis were repressed, whereas metabolic genes such as those for carbohydrate metabolism were enhanced in Q4359 and Q4646 seeds relative to N22. Expression of some genes involved in cell redox homeostasis and chromatin remodeling differed significantly only between Q4359 and N22. The results suggested a close correlation between cell redox homeostasis, chromatin remodeling and seed dormancy. In addition, some genes involved in ABA signaling were down-regulated, and several genes involved in GA biosynthesis and signaling were up-regulated. These observations suggest that reduced seed dormancy in Q4359 was regulated by ABA-GA antagonism. A few differentially expressed genes were located in the regions containing qSdn-1 and qSdn-5 suggesting that they could be candidate genes underlying seed dormancy. Our work provides useful leads to further determine the underling mechanisms of seed dormancy and for cloning seed dormancy genes from N22.
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Affiliation(s)
- Tao Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunyan Yang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Baoxu Ding
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhiming Feng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qian Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jun He
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianhua Tong
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha, 410128, China
| | - Langtao Xiao
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha, 410128, China
| | - Ling Jiang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Jianmin Wan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University, Nanjing, 210095, China; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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110
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Netto LES, de Oliveira MA, Tairum CA, da Silva Neto JF. Conferring specificity in redox pathways by enzymatic thiol/disulfide exchange reactions. Free Radic Res 2016; 50:206-45. [DOI: 10.3109/10715762.2015.1120864] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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111
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Direct structural evidence of protein redox regulation obtained by in-cell NMR. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:198-204. [PMID: 26589182 DOI: 10.1016/j.bbamcr.2015.11.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/04/2015] [Accepted: 11/07/2015] [Indexed: 12/30/2022]
Abstract
The redox properties of cellular environments are critical to many functional processes, and are strictly controlled in all living organisms. The glutathione-glutathione disulfide (GSH-GSSG) couple is the most abundant intracellular redox couple. A GSH redox potential can be calculated for each cellular compartment, which reflects the redox properties of that environment. This redox potential is often used to predict the redox state of a disulfide-containing protein, based on thermodynamic considerations. However, thiol-disulfide exchange reactions are often catalyzed by specific partners, and the distribution of the redox states of a protein may not correspond to the thermodynamic equilibrium with the GSH pool. Ideally, the protein redox state should be measured directly, bypassing the need to extrapolate from the GSH. Here, by in-cell NMR, we directly observe the redox state of three human proteins, Cox17, Mia40 and SOD1, in the cytoplasm of human and bacterial cells. We compare the observed distributions of redox states with those predicted by the GSH redox potential, and our results partially agree with the predictions. Discrepancies likely arise from the fact that the redox state of SOD1 is controlled by a specific partner, its copper chaperone (CCS), in a pathway which is not linked to the GSH redox potential. In principle, in-cell NMR allows determining whether redox proteins are at the equilibrium with GSH, or they are kinetically regulated. Such approach does not need assumptions on the redox potential of the environment, and provides a way to characterize each redox-regulating pathway separately.
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112
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Role and Regulation of Glutathione Metabolism in Plasmodium falciparum. Molecules 2015; 20:10511-34. [PMID: 26060916 PMCID: PMC6272303 DOI: 10.3390/molecules200610511] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/11/2015] [Accepted: 06/01/2015] [Indexed: 11/30/2022] Open
Abstract
Malaria in humans is caused by one of five species of obligate intracellular protozoan parasites of the genus Plasmodium. P. falciparum causes the most severe disease and is responsible for 600,000 deaths annually, primarily in Sub-Saharan Africa. It has long been suggested that during their development, malaria parasites are exposed to environmental and metabolic stresses. One strategy to drug discovery was to increase these stresses by interfering with the parasites’ antioxidant and redox systems, which may be a valuable approach to disease intervention. Plasmodium possesses two redox systems—the thioredoxin and the glutathione system—with overlapping but also distinct functions. Glutathione is the most abundant low molecular weight redox active thiol in the parasites existing primarily in its reduced form representing an excellent thiol redox buffer. This allows for an efficient maintenance of the intracellular reducing environment of the parasite cytoplasm and its organelles. This review will highlight the mechanisms that are responsible for sustaining an adequate concentration of glutathione and maintaining its redox state in Plasmodium. It will provide a summary of the functions of the tripeptide and will discuss the potential of glutathione metabolism for drug discovery against human malaria parasites.
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113
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Margittai É, Enyedi B, Csala M, Geiszt M, Bánhegyi G. Composition of the redox environment of the endoplasmic reticulum and sources of hydrogen peroxide. Free Radic Biol Med 2015; 83:331-40. [PMID: 25678412 DOI: 10.1016/j.freeradbiomed.2015.01.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/30/2015] [Accepted: 01/31/2015] [Indexed: 12/22/2022]
Abstract
The endoplasmic reticulum (ER) is a metabolically active organelle, which has a central role in proteostasis by translating, modifying, folding, and occasionally degrading secretory and membrane proteins. The lumen of the ER represents a separate compartment of the eukaryotic cell, with a characteristic proteome and metabolome. Although the redox metabolome and proteome of the compartment have not been holistically explored, it is evident that proper redox conditions are necessary for the functioning of many luminal pathways. These redox conditions are defined by local oxidoreductases and the membrane transport of electron donors and acceptors. The main electron carriers of the compartment are identical with those of the other organelles: glutathione, pyridine and flavin nucleotides, ascorbate, and others. However, their composition, concentration, and redox state in the ER lumen can be different from those observed in other compartments. The terminal oxidases of oxidative protein folding generate and maintain an "oxidative environment" by oxidizing protein thiols and producing hydrogen peroxide. ER-specific mechanisms reutilize hydrogen peroxide as an electron acceptor of oxidative folding. These mechanisms, together with membrane and kinetic barriers, guarantee that redox systems in the reduced or oxidized state can be present simultaneously in the lumen. The present knowledge on the in vivo conditions of ER redox is rather limited; development of new genetically encoded targetable sensors for the measurement of the luminal state of redox systems other than thiol/disulfide will contribute to a better understanding of ER redox homeostasis.
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Affiliation(s)
- Éva Margittai
- Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest 1444, Hungary
| | - Balázs Enyedi
- Department of Physiology, Semmelweis University, Budapest 1444, Hungary
| | - Miklós Csala
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest 1444, Hungary
| | - Miklós Geiszt
- Department of Physiology, Semmelweis University, Budapest 1444, Hungary; "Lendület" Peroxidase Enzyme Research Group of Semmelweis University and the Hungarian Academy of Sciences, Semmelweis University, Budapest 1444, Hungary
| | - Gábor Bánhegyi
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest 1444, Hungary.
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114
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Poole LB. The basics of thiols and cysteines in redox biology and chemistry. Free Radic Biol Med 2015; 80:148-57. [PMID: 25433365 PMCID: PMC4355186 DOI: 10.1016/j.freeradbiomed.2014.11.013] [Citation(s) in RCA: 597] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/20/2014] [Accepted: 11/17/2014] [Indexed: 02/06/2023]
Abstract
Cysteine is one of the least abundant amino acids, yet it is frequently found as a highly conserved residue within functional (regulatory, catalytic, or binding) sites in proteins. It is the unique chemistry of the thiol or thiolate group of cysteine that imparts to functional sites their specialized properties (e.g., nucleophilicity, high-affinity metal binding, and/or ability to form disulfide bonds). Highlighted in this review are some of the basic biophysical and biochemical properties of cysteine groups and the equations that apply to them, particularly with respect to pKa and redox potential. Also summarized are the types of low-molecular-weight thiols present in high concentrations in most cells, as well as the ways in which modifications of cysteinyl residues can impart or regulate molecular functions important to cellular processes, including signal transduction.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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115
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Abstract
Due to their susceptibility towards redox modification, protein thiols represent primary targets for the modulation of protein activity, conformation and oligomerization. Until fairly recently, such modifications were considered "damage" as a result of oxidative stress, before researchers recognized their physiological importance for biologic signaling. This paradigm shift, and the associated necessity to accurately characterize and quantify the various pathways of thiol redox modifications not only for specific proteins, but also within the cellular environment, has enticed researchers to take a close look at the impact of environment and molecular (protein) structure on these reactions. This Special Issue on Redox Biology of Thiols in Signaling Pathways is the result of a workshop organized at the 2013 Annual Meeting of the Society for Free Radical Biology and Medicine in San Antonio, Texas, summarizing the contributions from many of the presenters. It will provide a stimulating synopsis on what is known, and what is not known, about the reaction mechanisms which underlie the role of thiols and oxidative processes in signaling pathways.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157 USA
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, The University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
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