301
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Toledano MB, Delaunay A, Monceau L, Tacnet F. Microbial H2O2 sensors as archetypical redox signaling modules. Trends Biochem Sci 2004; 29:351-7. [PMID: 15236742 DOI: 10.1016/j.tibs.2004.05.005] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Michel B Toledano
- Laboratoire Stress Oxydants et Cancer, Service de Biologie Moléculaire Systémique, DBJC, DSV, CEA-Saclay, Bâtiment 142, 91191 Gif-sur-Yvette, France.
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302
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Abstract
Correct folding is essential to protein function, which has led to the evolution of sophisticated chaperone systems. Protein folding occurs primarily in the cytoplasm and in the endoplasmic reticulum (ER). The differing redox and ionic milieus inside these two compartments, and the different functions and destinations of the client proteins folded therein, have necessitated the existence of distinct chaperone networks. Both networks exploit the exquisite sensitivity of cysteines to redox state, but they respond in opposite directions, reflecting the different conditions in the cytosol (reducing) and in the ER (more oxidizing). Thus, the cytosolic chaperone Hsp33 forms active dimers in response to oxidation, linking the responses to thermal and oxidative stress, and allows the cell to "remember" the experience: Folded proteins are released upon Hsp33 reduction, whereas unfolded substrates are released only in the presence of additional chaperone complexes that are able to refold them. In contrast, the ER oxidoreductase protein disulphide isomerase (PDI) appears to function as a chaperone primarily when reduced. Owing to the reactivity of their thiol groups, cysteines provide molecular switches that can be used to control the folding and to reversibly modify the structure and function of a protein. Cysteine oxidation provides as versatile a system as protein phosphorylation for the modification of specific substrates and the propagation of signaling cascades. Moreover, it offers the important advantage that cysteines can undergo different modifications, thus providing a molecular code that rapidly reports and responds to redox changes in the environment.
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Affiliation(s)
- Roberto Sitia
- Università Vita-Salute San Raffaele, DiBiT, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy.
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303
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Marshall HE, Hess DT, Stamler JS. S-nitrosylation: physiological regulation of NF-kappaB. Proc Natl Acad Sci U S A 2004; 101:8841-2. [PMID: 15187230 PMCID: PMC428432 DOI: 10.1073/pnas.0403034101] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Harvey E Marshall
- Department of Medicine and Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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304
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Abstract
Reactive (low pKa) cysteine residues in proteins are critical components in redox signaling. A particularly reactive and versatile reversibly oxidized form of cysteine, the sulfenic acid (Cys-SOH), has important roles as a catalytic center in enzymes and as a sensor of oxidative and nitrosative stress in enzymes and transcriptional regulators. Depending on environment, sometimes the sulfenic acid provides a metastable oxidized form, and other times it is a fleeting intermediate giving rise to more stable disulfide, sulfinic acid, or sulfenyl-amide forms.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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305
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Zuber P. Spx-RNA polymerase interaction and global transcriptional control during oxidative stress. J Bacteriol 2004; 186:1911-8. [PMID: 15028674 PMCID: PMC374421 DOI: 10.1128/jb.186.7.1911-1918.2004] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Peter Zuber
- Department of Environmental and Biomolecular Systems, OGI School of Science & Engineering, Oregon Health & Science University, Beaverton, Oregon 97006, USA.
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306
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Haridas V, Hanausek M, Nishimura G, Soehnge H, Gaikwad A, Narog M, Spears E, Zoltaszek R, Walaszek Z, Gutterman JU. Triterpenoid electrophiles (avicins) activate the innate stress response by redox regulation of a gene battery. J Clin Invest 2004; 113:65-73. [PMID: 14702110 PMCID: PMC300766 DOI: 10.1172/jci18699] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2003] [Accepted: 10/28/2003] [Indexed: 11/17/2022] Open
Abstract
Avicins are proapoptotic and anti-inflammatory triterpene electrophiles isolated from an Australian desert tree, Acacia victoriae. The presence of two alpha,beta unsaturated carbonyl groups (Michael reaction sites) in the side chain of the avicin molecule prompted us to study its effects on NF-E2-related factor 2 (Nrf2), a redox-regulated transcription factor that controls the expression of a battery of detoxification and antioxidant proteins via its binding to antioxidant response element (ARE). Avicin D-treated Hep G2 cells showed translocation of Nrf2 into the nucleus and a time-dependent increase in ARE activity. These properties were sensitive to DTT, suggesting that avicins affect one or more critical cysteine residues, probably on the Keap1 molecule. Downstream of ARE, an activation of a battery of stress-induced proteins occurred. The implications of these findings were evaluated in vivo in mouse skin exposed to an ancient stressor, UV light. Avicins inhibited epidermal hyperplasia, reduced p53 mutation, enhanced apoptosis, decreased generation of 8-hydroxy-2'-deoxyguanosine, and enhanced expression of NADPH:quinone oxidoreductase 1 and heme oxygenase-1. These data, combined with our earlier published work, demonstrate that avicins represent a new class of plant stress metabolites capable of activating stress adaptation and suppressing proinflammatory components of the innate immune system in human cells by redox regulation. The relevance for treatment of clinical diseases in which stress responses are dysfunctional or deficient is discussed.
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Affiliation(s)
- Valsala Haridas
- Department of Molecular Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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307
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Fernandes AP, Holmgren A. Glutaredoxins: glutathione-dependent redox enzymes with functions far beyond a simple thioredoxin backup system. Antioxid Redox Signal 2004; 6:63-74. [PMID: 14713336 DOI: 10.1089/152308604771978354] [Citation(s) in RCA: 480] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Most cells contain high levels of glutathione and multiple glutaredoxins, which utilize the reducing power of glutathione to catalyze disulfide reductions in the presence of NADPH and glutathione reductase (the glutaredoxin system). Glutaredoxins, like thioredoxins, may operate as dithiol reductants and are involved as alternative pathways in cellular functions such as formation of deoxyribonucleotides for DNA synthesis (by reducing the essential enzyme ribonucleotide reductase), the generation of reduced sulfur (via 3'-phosphoadenylylsulfate reductase), signal transduction, and the defense against oxidative stress. The three dithiol glutaredoxins of E. coli with the active-site sequence CPYC and a glutathione binding site in a thioredoxin/glutaredoxin fold display surprisingly different properties. These include the inducible OxyR-regulated 10-kDa Grx1 or the highly abundant 24-kDa glutathione S-transferase-like Grx2 (with Grx3 it accounts for 1% of total protein). Glutaredoxins uniquely reduce mixed disulfides with glutathione via a monothiol mechanism where only an N-terminal low pKa Cys residue is required, by using their glutathione binding site. Glutaredoxins also catalyze formation of mixed disulfides (glutathionylation), which is an important redox regulatory mechanism, particularly in mammalian cells under oxidative stress conditions, to sense cellular redox potential.
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Affiliation(s)
- Aristi Potamitou Fernandes
- Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
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308
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Mukhopadhyay P, Zheng M, Bedzyk LA, LaRossa RA, Storz G. Prominent roles of the NorR and Fur regulators in the Escherichia coli transcriptional response to reactive nitrogen species. Proc Natl Acad Sci U S A 2004; 101:745-50. [PMID: 14718666 PMCID: PMC321752 DOI: 10.1073/pnas.0307741100] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We examined the genomewide transcriptional responses of Escherichia coli treated with nitrosylated glutathione or the nitric oxide (NO)-generator acidified sodium nitrite (NaNO(2)) during aerobic growth. These assays showed that NorR, a homolog of NO-responsive transcription factors in Ralstonia eutrophus, and Fur, the global repressor of ferric ion uptake, are major regulators of the response to reactive nitrogen species. In contrast, SoxR and OxyR, regulators of the E. coli defenses against superoxide-generating compounds and hydrogen peroxide, respectively, have minor roles. Moreover, additional regulators of the E. coli response to reactive nitrogen species remain to be identified because several of the induced genes were regulated normally in norR, fur, soxRS, and oxyR mutant strains. We propose that the E. coli transcriptional response to reactive nitrogen species is a composite response mediated by the modification of multiple transcription factors containing iron or redox-active cysteines, some specifically designed to sense NO and its derivatives and others that are collaterally activated by the reactive nitrogen species.
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Affiliation(s)
- Partha Mukhopadhyay
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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309
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Michel KP, Pistorius EK. Adaptation of the photosynthetic electron transport chain in cyanobacteria to iron deficiency: The function of IdiA and IsiA. PHYSIOLOGIA PLANTARUM 2004; 120:36-50. [PMID: 15032875 DOI: 10.1111/j.0031-9317.2004.0229.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this review we give an overview on the adaptational responses of photosystem (PS) II and PSI in cyanobacteria to iron starvation, mainly summarizing our results with the mesophilic Synechococcus elongatus PCC 7942. We also discuss this process with respect to the strong interrelationship between iron limitation and oxidative stress that exists in cyanobacteria as oxygenic photosynthetic organisms. The adaptation of the multiprotein complexes PSII and PSI to iron starvation is a sequential process, which is characterized by the enhanced expression of two major iron-regulated proteins, IdiA (iron deficiency induced protein A) and IsiA (iron stress induced protein A). Our results suggest that IdiA protects the acceptor side of PSII against oxidative stress under conditions of mild iron limitation in a currently unclear way, whereas prolonged iron deficiency leads to the synthesis of a chlorophyll a antenna around PSI-trimers consisting of IsiA molecules. The physiological consequences of these alterations under prolonged iron starvation, as shown by acridine yellow fluorescence measurements, are a reduction of linear electron transport activity through PSII and an increase of cyclic electron flow around PSI as well as an increase in respiratory activity. IdiA and IsiA expression are mediated by two distinct helix-turn-helix transcriptional regulators of the Crp/Fnr family. IdiB positively regulates expression of idiA under iron starvation, and Fur represses transcription of isiA under iron-sufficient conditions. Although both transcriptional regulators seem to operate independently of each other, our results indicate that a cross-talk between the signal transduction pathways exists. Moreover, IdiA as well as IsiA expression are affected by hydrogen peroxide. We suggest that due to the interdependence of iron limitation and the formation of reactive oxygen species, peroxide stress might be the superior trigger that leads to expression of these proteins under iron starvation. The modifications of PSII and PSI under iron starvation influence the redox state of redox-sensitive components of the electron transport chain, and thus the activity of metabolic pathways being regulated in dependence of the redox state of these components.
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Affiliation(s)
- Klaus-Peter Michel
- Biologie VIII: Molekulare Zellphysiologie, Universität Bielefeld, D-33501 Bielefeld, Germany
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310
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Rhoads DM, Vanlerberghe GC. Mitochondria-Nucleus Interactions: Evidence for Mitochondrial Retrograde Communication in Plant Cells. PLANT MITOCHONDRIA: FROM GENOME TO FUNCTION 2004. [DOI: 10.1007/978-1-4020-2400-9_5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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311
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Saraiva LM, Vicente JB, Teixeira M. The Role of the Flavodiiron Proteins in Microbial Nitric Oxide Detoxification. Adv Microb Physiol 2004; 49:77-129. [PMID: 15518829 DOI: 10.1016/s0065-2911(04)49002-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The flavodiiron proteins (first named as A-type flavoproteins) constitute a large superfamily of enzymes, widespread among anaerobic and facultative anaerobic prokaryotes, from both the Archaea and Bacteria domains. Noticeably, genes encoding for homologous enzymes are also present in the genomes of some pathogenic and anaerobic amitochondriate protozoa. The fingerprint of this enzyme family is the conservation of a two-domain structural core, built by a metallo-beta-lactamase-like domain, at the N-terminal region, harbouring a non-heme diiron site, and a flavodoxin-like domain, containing one FMN moiety. These enzymes have a significant nitric oxide reductase activity, and there is increasing evidence that they are involved in microbial resistance to nitric oxide. In this review, we will discuss available data for this novel family of enzymes, including their physicochemical properties, structural and phylogenetic analyses, enzymatic properties and the molecular genetic approaches so far used to tackle their function.
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Affiliation(s)
- Lígia M Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127 Avenida da República (EAN), 2781-901 Oeiras, Portugal
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312
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Haridas V, Hanausek M, Nishimura G, Soehnge H, Gaikwad A, Narog M, Spears E, Zoltaszek R, Walaszek Z, Gutterman JU. Triterpenoid electrophiles (avicins) activate the innate stress response by redox regulation of a gene battery. J Clin Invest 2004. [DOI: 10.1172/jci200418699] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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313
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Bae JB, Park JH, Hahn MY, Kim MS, Roe JH. Redox-dependent Changes in RsrA, an Anti-sigma Factor in Streptomyces coelicolor: Zinc Release and Disulfide Bond Formation. J Mol Biol 2004; 335:425-35. [PMID: 14672653 DOI: 10.1016/j.jmb.2003.10.065] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
sigmaR is a sigma factor for transcribing genes to defend cells against oxidative stresses in the antibiotic-producing bacterium Streptomyces coelicolor. The availability of sigmaR is regulated by RsrA, an anti-sigma factor, whose sigmaR-binding activity is regulated by redox changes in the environment, via thiol-disulfide exchange. We found that reduced RsrA contains zinc in a stoichiometric amount, whereas oxidized form has very little: 1 mol of zinc per mol of RsrA was released upon oxidation as monitored by a chromogenic Zn-chelator, 4-(2-pyridylazo)-resorcinol (PAR). Measurement of zinc bound in several RsrA mutants of various cysteine and histidine substitutions suggested that C3, H7, C41, and C44 serve as zinc-binding sites. The zinc-binding and sigmaR-binding activities of mutant proteins did not coincide, suggesting that zinc might not be absolutely required for the anti-sigma activity of RsrA. Zn-free apo-RsrA bound sigmaR and inhibited sigmaR-dependent transcription in vitro. Compared with Zn-RsrA, the anti-transcription activity of apo-RsrA was about threefold lower and its sigmaR-binding affinity decreased by about ninefold when measured by surface plasmon resonance analysis. Apo-RsrA was more sensitive to protease, suggesting that zinc allows RsrA to maintain a more compact structure, optimized for binding sigmaR. The cysteine pairs that form disulfide bonds were determined by MALDI-TOF mass spectrometry, revealing formation of the critical disulfide bond between C11 and one of the essential cysteine residues C41 or 44, most likely C44. An improved model for the mechanism of redox-modulation of RsrA was presented.
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Affiliation(s)
- Jae-Bum Bae
- School of Biological Sciences and Institute of Microbiology, Seoul National University, 151-742, Seoul, South Korea
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314
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Matalon S, Hardiman KM, Jain L, Eaton DC, Kotlikoff M, Eu JP, Sun J, Meissner G, Stamler JS. Regulation of ion channel structure and function by reactive oxygen-nitrogen species. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1184-9. [PMID: 14604848 DOI: 10.1152/ajplung.00281.2003] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Ion channels subserve diverse cellular functions. Reactive oxygen and nitrogen species modulate ion channel function by a number of mechanisms including 1) transcriptional regulation of gene expression, 2) posttranslational modifications of channel proteins, i.e. nitrosylation, nitration, and oxidation of key amino acid residues, 3) by altering the gain in other signaling pathways that may in turn lead to changes in channel activity or channel gene expression, and 4) by modulating trafficking or turnover of channel proteins, as typified by oxygen radical activation of NF-kappa B, with subsequent changes in proteasomal degradation of channel degradation. Regardless of the mechanism, as was discussed in a symposium at the 2003 Experimental Biology Meeting in San Diego, CA, changes in the cellular level of reactive oxygen and nitrogen species can have profound effects on the activity of ion channels and cellular function.
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Affiliation(s)
- Sadis Matalon
- Department of Physiology, University of Alabama at Birmingham, Rm. 224, BMR II, 901 S. 19th St., Birmingham, AL 35205-3703, USA.
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315
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Gilchrist M, Hesslinger C, Befus AD. Tetrahydrobiopterin, a critical factor in the production and role of nitric oxide in mast cells. J Biol Chem 2003; 278:50607-14. [PMID: 14514683 DOI: 10.1074/jbc.m307777200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mast cells (MC) are biologically potent, ubiquitously distributed immune cells with fundamental roles in host integrity and disease. MC diversity and function is regulated by exogenous nitric oxide; however, the production and function of endogenously produced NO in MC is enigmatic. We used rat peritoneal MC (PMC) as an in vivo model to examine intracellular NO production. Live cell confocal analysis of PMC using the NO-sensitive probe diaminofluorescein showed distinct patterns of intracellular NO formation with either antigen (Ag)/IgE (short term) or interferon-gamma (IFN-gamma) (long term). Ag/IgE-induced NO production is preceded by increased intracellular Ca2+, implying constitutive nitric-oxide synthase (NOS) activity. NO formation inhibits MC degranulation. NOS has obligate requirements for tetrahydrobiopterin (BH4), a product of GTP-cyclohydrolase I (CHI), IFN-gamma-stimulated PMC increased CHI mRNA, protein, and enzymatic activity, while decreasing CHI feedback regulatory protein mRNA, causing sustained NO production. Treatment with the CHI inhibitor, 2,4-diamino-6-hydroxypyrimidine, inhibited NO in both IFN-gamma and Ag/IgE systems, increasing MC degranulation. Reconstitution with the exogenous BH4 substrate, sepiapterin, restored NO formation and inhibited exocytosis. Thus, Ag/IgE and IFN-gamma induced intracellular NO plays a key role in MC mediator release, and alterations in NOS activity via BH4 availability may be critical to the heterogeneous responsiveness of MC.
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Affiliation(s)
- Mark Gilchrist
- Glaxo-Heritage Asthma Research Laboratory, Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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316
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Abstract
Thiol-based regulatory switches play central roles in cellular responses to oxidative stress, nitrosative stress, and changes in the overall thiol-disulfide redox balance. Protein sulfhydryls offer a great deal of flexibility in the different types of modification they can undergo and the range of chemical signals they can perceive. For example, recent work on OhrR and OxyR has clearly established that disulfide bonds are not the only cysteine oxidation products that are likely to be relevant to redox sensing in vivo. Furthermore, different stresses can result in distinct modifications to the same protein; in OxyR it seems that distinct modifications can occur at the same cysteine, and in Yap1 a partner protein ensures that the disulfide bond induced by peroxide stress is different from the disulfide bond induced by other stresses. These kinds of discoveries have also led to the intriguing suggestion that different modifications to the same protein can create multiple activation states and thus deliver discrete regulatory outcomes. In this review, we highlight these issues, focusing on seven well-characterized microbial proteins controlled by thiol-based switches, each of which exhibits unique regulatory features.
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Affiliation(s)
- Mark S B Paget
- Department of Biochemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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317
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Fraser JA, Kansagra P, Kotecki C, Saunders RDC, McLellan LI. The modifier subunit of Drosophila glutamate-cysteine ligase regulates catalytic activity by covalent and noncovalent interactions and influences glutathione homeostasis in vivo. J Biol Chem 2003; 278:46369-77. [PMID: 12954617 DOI: 10.1074/jbc.m308035200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamate-cysteine ligase (GCL) has a key influence on glutathione homeostasis. It has been proposed that mammalian GCL is regulated by the redox environment, and we show here that cysteine residues in the Drosophila melanogaster GCL modifier subunit (DmGCLM) can form covalent interactions with the catalytic subunit (DmGCLC) and modify its activity. Candidate components of intersubunit disulfides (Cys213, Cys214, and Cys267) were identified using matrix-assisted laser desorption ionization time-of-flight spectroscopy of iodoacetamide-modified DmGCLM as well as examination of the evolutionary conservation of cysteines. Mutation of the 3 cysteine residues allowed DmGCLM to associate with DmGCLC, but inhibited the formation of intersubunit disulfides. This caused a 2-fold reduction in the catalytic efficiency of Drosophila GCL, although activity remained significantly higher than the catalytic subunit alone. The cysteine mutant was also more sensitive to inhibition by glutathione than the unmodified holoenzyme. Notably, human GCLM could substitute for DmGCLM in modification of DmGCLC activity. The role of DmGCLM in vivo was examined by analysis of a Drosophila mutant (l(3)L0580) containing a P-element insertion in Gclm. We found that the P-element is not responsible for the lethal phenotype and separated the recessive lethal mutation from the P-element by recombination. This yielded two fully viable and fertile recombinants bearing the P-element insertion, which Western and Northern blotting indicated is a severely hypomorphic allele of Gclm. Glutathione levels were approximately 2-fold lower in the GclmL0580 mutants than in control strains, demonstrating the importance of DmGCLM in the regulation of glutathione homeostasis in vivo.
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Affiliation(s)
- Jennifer A Fraser
- Biomedical Research Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, UK
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318
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Li W, Bottrill AR, Bibb MJ, Buttner MJ, Paget MSB, Kleanthous C. The Role of zinc in the disulphide stress-regulated anti-sigma factor RsrA from Streptomyces coelicolor. J Mol Biol 2003; 333:461-72. [PMID: 14529630 DOI: 10.1016/j.jmb.2003.08.038] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The regulation of disulphide stress in actinomycetes such as Streptomyces coelicolor is known to involve the zinc-containing anti-sigma factor RsrA that binds and inactivates the redox-regulated sigma factor sigmaR. However, it is not known how RsrA senses disulphide stress nor what role the metal ion plays. Using in vitro assays, we show that while zinc is not required for sigmaR binding it is required for functional anti-sigma factor activity, and that it plays a critical role in modulating the reactivity of RsrA cysteine thiol groups towards oxidation. Apo-RsrA is easily oxidised and, while the Zn-bound form is relatively resistant, the metal ion is readily expelled when the protein is treated with strong oxidants such as diamide. We also show, using a combination of proteolysis and mass spectrometry, that the first critical disulphide to form in RsrA involves Cys11 and one of either Cys41 or Cys44, all previously implicated in metal binding. Circular dichroism spectroscopy was used to follow structural changes during oxidation of RsrA, which indicated that concomitant with formation of this critical disulphide bond is a major restructuring of the protein where its alpha-helical content increases. Our data demonstrate that RsrA can only bind sigmaR in the reduced state and that this state is stabilised by zinc. Redox stress induces disulphide bond formation amongst zinc-ligating residues, expelling the metal ion and stabilising a structure incapable of binding the sigma factor.
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Affiliation(s)
- Wei Li
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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319
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Hemish J, Nakaya N, Mittal V, Enikolopov G. Nitric oxide activates diverse signaling pathways to regulate gene expression. J Biol Chem 2003; 278:42321-9. [PMID: 12907672 DOI: 10.1074/jbc.m308192200] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric oxide signaling is crucial for effecting long lasting changes in cells, including gene expression, cell cycle arrest, apoptosis, and differentiation. We have determined the temporal order of gene activation induced by NO in mammalian cells and have examined the signaling pathways that mediate the action of NO. Using microarrays to study the kinetics of gene activation by NO, we have determined that NO induces three distinct waves of gene activity. The first wave is induced within 30 min of exposure to NO and represents the primary gene targets of NO. It is followed by subsequent waves of gene activity that may reflect further cascades of NO-induced gene expression. We verified our results using quantitative real time PCR and further validated our conclusions about the effects of NO by using cytokines to induce endogenous NO production. We next applied pharmacological and genetic approaches to determine the signaling pathways that are used by NO to regulate gene expression. We used inhibitors of particular signaling pathways, as well as cells from animals with a deleted p53 gene, to define groups of genes that require phosphatidylinositol 3-kinase, protein kinase C, NF-kappaB, p53, or combinations thereof for activation by NO. Our results demonstrate that NO utilizes several independent signaling pathways to induce gene expression.
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Affiliation(s)
- Jill Hemish
- Cold Spring Harbor Laboratory, 1 Bungtown Road, PO Box 100, Cold Spring Harbor, NY 11724, USA
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320
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Azevedo D, Tacnet F, Delaunay A, Rodrigues-Pousada C, Toledano MB. Two redox centers within Yap1 for H2O2 and thiol-reactive chemicals signaling. Free Radic Biol Med 2003; 35:889-900. [PMID: 14556853 DOI: 10.1016/s0891-5849(03)00434-9] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Yap1 transcription factor regulates yeast responses to H2O2 and to several unrelated chemicals and metals. Activation by H2O2 involves Yap1 Cys303-Cys598 intra-molecular disulfide bond formation directed by the H2O2 sensor Orp1/Gpx3. We show here that the electrophile N-ethylmaleimide activates Yap1 by covalent modification of Yap1 C-terminal Cys598, Cys620, and Cys629, in an Orp1 and Yap1-oxidation-independent way, thus establishing an alternate and distinct mode of Yap1 activation. We also show that menadione, a superoxide anion generator and a highly reactive electrophile, operates both modes of Yap1 activation. Further, the Yap1 C-terminal domain reactivity towards other electrophiles (4-hydroxynonenal, iodoacetamide) and metals (cadmium, selenium) suggests a common mechanism for sensing thiol reactive chemicals, involving thiol chemical modification. We propose that Yap1 has two distinct molecular redox centers, one triggered by ROS (hydroperoxides and the superoxide anion) and the other by chemicals with thiol reactivity (electrophiles and divalent heavy metals cations). These data indicate that yeast cells cannot sense these compounds through the same molecular devices, albeit they are all electrophilic.
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Affiliation(s)
- Dulce Azevedo
- Laboratoire Stress Oxydants et Cancers, Service de Biochimie et de Génétique Moléculaire, Département de Biologie Joliot Curie, CEA-Saclay, Gif-sur-Yvette, France
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321
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Sun XZ, Vinci C, Makmura L, Han S, Tran D, Nguyen J, Hamann M, Grazziani S, Sheppard S, Gutova M, Zhou F, Thomas J, Momand J. Formation of disulfide bond in p53 correlates with inhibition of DNA binding and tetramerization. Antioxid Redox Signal 2003; 5:655-65. [PMID: 14580323 DOI: 10.1089/152308603770310338] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The p53 tumor suppressor protein is susceptible to oxidation, which prevents it from binding to its DNA response element. The goal of the current research was to determine the nature of the cysteine residue thiol oxidation that prevents p53 from binding its DNA target and its effect on p53 structure. Recombinant p53, purified in the presence of the reducing agent dithiothreitol (DTT), contains five free thiol groups on the surface of the protein. In the absence of DTT, p53 contains only four thiol groups, indicating that an average of one surface thiol group is readily susceptible to oxidation. Sulfite-mediated disulfide bond cleavage followed by reaction with 2-nitro-5-thiosulfobenzoate showed that oxidized p53 contains a single disulfide bond per monomer. By atomic force microscopy, we determined that reduced p53 binds to a double-stranded DNA containing the p53 promoter element of the MDM2 gene. The DNA-bound reduced p53 has an average cross-sectional diameter of 8.61 nm and a height of 4.12 nm. The amount of oxidized p53 that bound to the promoter element was ninefold lower, and it has an 18% larger average cross-sectional diameter. Electromobility shift assays showed that binding of oxidized p53 to DNA was enhanced upon addition of DTT, indicating that oxidation is reversible. The possibility that oxidized p53 contained significant amounts of sulfenic (-SOH), sulfinic (-SO2H), or sulfonic acid (-SO3H) was ruled out. Gel filtration chromatography indicated that oxidation increases the percentage of p53 monomers and high-molecular-weight oligomers (>1,000 kDa) relative to tetrameric p53. Protein modeling studies suggest that a mixed disulfide glutathione adduct on Cys182 could account for the observed stoichiometry of oxidized thiols and structural changes. The glutathione adduct may prevent proper helix-helix interaction within the DNA binding domain and contribute to tetramer dissociation.
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Affiliation(s)
- Xiu Zhu Sun
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA 90032, USA
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322
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Swem LR, Kraft BJ, Swem DL, Setterdahl AT, Masuda S, Knaff DB, Zaleski JM, Bauer CE. Signal transduction by the global regulator RegB is mediated by a redox-active cysteine. EMBO J 2003; 22:4699-708. [PMID: 12970182 PMCID: PMC212728 DOI: 10.1093/emboj/cdg461] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
All living organisms alter their physiology in response to changes in oxygen tension. The photosynthetic bacterium uses the RegB-RegA signal transduction cascade to control a wide variety of oxygen-responding processes such as respiration, photosynthesis, carbon fixation and nitrogen fixation. We demonstrate that a highly conserved cysteine has a role in controlling the activity of the sensor kinase, RegB. In vitro studies indicate that exposure of RegB to oxidizing conditions results in the formation of an intermolecular disulfide bond and that disulfide bond formation is metal-dependent, with the metal fulfilling a structural role. Formation of a disulfide bond in vitro is also shown to convert the kinase from an active dimer into an inactive tetramer state. Mutational analysis indicates that a cysteine residue flanked by cationic amino acids is involved in redox sensing in vitro and in vivo. These residues appear to constitute a novel 'redox-box' that is present in sensor kinases from diverse species of bacteria.
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Affiliation(s)
- Lee R Swem
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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323
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Abstract
In early starvation tissue protein degradation increases, however in later starvation proteolysis declines so as to pace gradual atrophy during synthetic failure. Secondary decline of proteolytic pathways under progressive nutritional desperation is unexplained. After several days of starvation tissue GSH is partly depleted and GSSG/GSH is increased, followed by onset of ketonemia from fat breakdown. Ketone bodies inexplicably delay net muscle protein loss. Recent studies identify a proteome subset of more than 200 proteins with reactive sulfhydryl sites as candidates for coordinate redox control of diverse cell functions. Ketones cause protein sulfhydryl oxidation and protein S-glutathionylation. Here, redox-responsive proteolytic pathways were bio-assayed by release of [3H]leucine from rat myocardium under non-recirculating perfusion. More than 75% of myocardial protein degradation was inhibited and defined by infusion of diamide (100 microM) under constant physiologic concentrations of complete amino acids. Diamide-inhibitable proteolysis includes all lysosomal and some extra-lysosomal proteolysis. Following diamide washout, the reversal of proteolytic inhibitory action was greatly enhanced by artificial repletion of GSH by supra-physiologic extra-cellular GSH (1mM) exposure. Therefore, GSH maintains much of constitutive protein degradation in a primary tissue bioassay. Physiologic acetoacetate infusion (5mM) inhibited redox-responsive protein degradation. Uniformly [3H]leucine labeled 3T3 cells exhibited similar redox-dependent and redox-independent subcomponents of protein degradation. Independent of ketones, steady state cathepsin B reaction rate ex vivo was graded in proportion to the GSH concentration without GSSG, and inversely proportional to the GSSG/GSH redox ratio with inhibitory threshold at 0.5% oxidized. Linkage of some cysteine protease reaction rates to the interplay between GSH-GSSG/GSH status and ketonemia is suggested among transcendent mechanisms coordinating and pacing proteome turnover under prolonged starvation. The possibility of pre-emptive, redox coordination of distinct proteolytic pathways is speculatively discussed.
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Affiliation(s)
- Thomas D Lockwood
- Department of Pharmacology, School of Medicine, Wright State University, Cox Bldg, 3525 Southern Blvd, Kettering, OH 45429, USA.
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324
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Abstract
Human metallothionein-3 (MT-3) is a neuronal inhibitory factor mainly expressed in brain and downregulated in Alzheimer's disease. The neuroinhibitory activity has been established for native Cu(4),Zn(3)-MT-3 and recombinant Zn(7)-MT-3. However, there is only limited knowledge about the structure and properties of the former metalloform. We have now generated native-like MT-3 through direct Cu(I) and Zn(II) incorporation into the recombinant apoprotein. Its characterization revealed monomeric Cu(4),Zn(4)-MT-3 containing metal-thiolate clusters located in two mutually interacting protein domains, a Cu(4) cluster in the beta-domain and a Zn(4) cluster in the alpha-domain. Using the PC12 cell line, the nontoxic nature of the protein was demonstrated. The results of electronic absorption and Cu(I) luminescence at 77 K showed that the Cu(4) cluster possesses an unprecedented stability in air. In contrast, the Zn(4) cluster is air sensitive. Its oxidation results in the release of one Zn(II) and the formation of a Zn(3) cluster, i.e., Cu(4),Zn(3)-MT-3. This process can be prevented or reversed under reducing conditions. The determined apparent stability constant for the Zn(4) cluster of 2.4 x 10(11) M(-1) is similar to that obtained for other zinc-containing MTs. This suggests that a substantially increased nucleophilic reactivity of specific thiolate ligands is responsible for this effect. Thus, the Zn(4) cluster in MT-3 may play a redox-dependent regulatory role.
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Affiliation(s)
- Bernd Roschitzki
- Institute of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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325
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Abstract
Cellular compartments differ dramatically in their redox potentials. This translates directly into variations in the extent of disulfide bond formation within proteins, depending on their cellular localization. It has long been assumed that proteins that are present in the reducing environment of the cytosol do not possess disulfide bonds. The recent discovery of a number of cytosolic proteins that use specific and reversible disulfide bond formation as a functional switch suggests that this view needs to be revised. Oxidative stress-induced disulfide bond formation appears to be the main strategy to adjust the protein activity of the oxidative stress transcription factors Yap1 and OxyR, the molecular chaperone Hsp33, and the anti-sigma factor RsrA. This elegant and rapid regulation allows the cells to respond quickly to environmental changes that manifest themselves in the accumulation of reactive oxygen species.
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Affiliation(s)
- Katrin Linke
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
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326
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Tanaka H, Sakurai K, Takahashi K, Fujimoto Y. Requirement of intracellular free thiols for hydrogen peroxide-induced hypertrophy in cardiomyocytes. J Cell Biochem 2003; 89:944-55. [PMID: 12874829 DOI: 10.1002/jcb.10568] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reactive oxygen species (ROS) are by-products of aerobic metabolism and are implicated in the pathogenesis of several diseases. H(2)O(2) produces oxidative stress and acts as a second messenger in several cell types. We tested whether the effect of H(2)O(2) on cellular events could be altered by changes in the intracellular redox status in a cardiomyocyte cell line. Using flow cytometric measurements, we found that adding H(2)O(2) induced hypertrophy in control cells in a time-dependent manner. Pre-incubation of the cells with buthionine sulfoximine (BSO), an inhibitor of de novo GSH synthesis, induced increase in the number of cells of small sizes by the addition of H(2)O(2) as compared to non-BSO pre-incubated control cells, and exacerbated the decrease in viability. Total thiol and GSH levels in H9c2 cells pre-incubated with BSO were about 75 and 30% of control, respectively, and GSH levels fell to below the limitation of detection after the addition of H(2)O(2), although total thiol levels were not markedly decreased. In the cells pre-incubated with BSO, hypertrophy was not observed by the addition of H(2)O(2) at any level of concentration. N-acetyl-L-cysteine and cysteine not only prevented increase in the number of cells of small sizes caused by H(2)O(2) but also induced hypertrophy in cells pre-incubated with BSO. These results suggest that the intracellular free thiol levels determine whether cell death or hypertrophy occurs in cardiomyocytes in the presence of H(2)O(2). On the other hand, the hypertrophied cells did not become larger by adding H(2)O(2), but had high levels of cellular GSH, suggesting the possibility that the hypertrophied cells have tolerance to oxidative stress.
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Affiliation(s)
- Hiroyuki Tanaka
- Department of Biochemistry, Hokkaido College of Pharmacy, 7-1 Katsuraoka-cho, Otaru City, Hokkaido 047-0264, Japan
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327
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Cohen MF, Yamasaki H. Involvement of nitric oxide synthase in sucrose-enhanced hydrogen peroxide tolerance of Rhodococcus sp. strain APG1, a plant-colonizing bacterium. Nitric Oxide 2003; 9:1-9. [PMID: 14559426 DOI: 10.1016/s1089-8603(03)00043-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogen peroxide (H2O2) tolerance of Rhodococcus sp. strain APG1, previously isolated from the aquatic fern Azolla pinnata, was examined in relation to nitric oxide (NO) production by cells cultured on a variety of C sources. Cells inoculated onto A. pinnata fronds established a surface-sterilant resistant density of 2-4x10(7) cells g(-1) without causing disease. Compared to cultures containing glucose, fructose, mannitol, or glycerol, those provided only with sucrose displayed, on a per C basis, substantially lower (<10%) growth yields and higher resistance to H2O2. NO, a positive regulator of catalase synthesis in bacteria, was produced in larger amounts in sucrose-grown cells as evidence by eightfold greater per cell accumulations in the medium of nitrite (NO2-), a stable oxidation product of NO. Addition to cells of L-arginine, the substrate for nitric oxide synthase (NOS), stimulated production of NO, detected both by fluorometric reaction with diaminofluorescein-FM diacetate (DAF-FM DA) and by increased levels of NO2- in the culture medium. These results suggest that sucrose may enhance H2O2 tolerance of Rhodococcus APG1 by increasing cellular NO producing capacity. We propose a regulatory role for NOS in promoting tolerance of Rhodococcus APG1 to oxidative stress in the phyllosphere.
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Affiliation(s)
- Michael F Cohen
- Division of Functional Genomics, Center of Molecular Biosciences, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan
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328
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André M, Felley-Bosco E. Heme oxygenase-1 induction by endogenous nitric oxide: influence of intracellular glutathione. FEBS Lett 2003; 546:223-7. [PMID: 12832044 DOI: 10.1016/s0014-5793(03)00576-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To investigate the influence of glutathione (GSH) on cellular effects of nitric oxide (NO) formation, human colon adenocarcinoma cells were transfected with a vector allowing controlled expression of inducible nitric oxide synthase (iNOS). Protein levels of oxidative stress-sensitive heme oxygenase-1 (HO-1) were analyzed in the presence or absence of GSH depletion using L-buthionine-[S,R]-sulfoximine and iNOS induction. While no effect was observed in the presence of iNOS activity alone, a synergistic effect on HO-1 expression was observed in the presence of iNOS expression and GSH depletion. This effect was prevented by addition of N-methyl-L-arginine. Therefore, targeting of endogenous NO may be modulated by intracellular GSH.
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Affiliation(s)
- Muriel André
- Institute of Pharmacology and Toxicology, Rue du Bugnon 27, 1005 Lausanne, Switzerland
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329
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Uprichard SL, Knipe DM. Conformational changes in the herpes simplex virus ICP8 DNA-binding protein coincident with assembly in viral replication structures. J Virol 2003; 77:7467-76. [PMID: 12805446 PMCID: PMC164794 DOI: 10.1128/jvi.77.13.7467-7476.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The herpes simplex virus (HSV) single-stranded DNA-binding protein, ICP8, is required for viral DNA synthesis. Before viral DNA replication, ICP8 colocalizes with other replication proteins at small punctate foci called prereplicative sites. With the onset of viral genome amplification, these proteins become redistributed into large globular replication compartments. Here we present the results of immunocytochemical and biochemical analysis of ICP8 showing that various antibodies recognize distinct forms of ICP8. Using these ICP8-specific antibodies as probes for ICP8 structure, we detected a time-dependent appearance and disappearance of ICP8 epitopes in immunoprecipitation assays. Immunofluorescence staining of ICP8 in cells infected with different HSV mutant viruses as well as cells transfected with a limited number of viral genes demonstrated that these and other antigenic changes occur coincident with ICP8 assembly at intranuclear replication structures. Genetic analysis has revealed a correlation between the ability of various ICP8 mutant proteins to form the 39S epitope and their ability to bind to DNA. These results support the hypothesis that ICP8 undergoes a conformational change upon binding to other HSV proteins and/or to DNA coincident with assembly into viral DNA replication structures.
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Affiliation(s)
- Susan L Uprichard
- Committee on Virology and Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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330
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Mou Z, Fan W, Dong X. Inducers of plant systemic acquired resistance regulate NPR1 function through redox changes. Cell 2003; 113:935-44. [PMID: 12837250 DOI: 10.1016/s0092-8674(03)00429-x] [Citation(s) in RCA: 852] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
NPR1 is an essential regulator of plant systemic acquired resistance (SAR), which confers immunity to a broad-spectrum of pathogens. SAR induction results in accumulation of the signal molecule salicylic acid (SA), which induces defense gene expression via activation of NPR1. We found that in an uninduced state, NPR1 is present as an oligomer formed through intermolecular disulfide bonds. Upon SAR induction, a biphasic change in cellular reduction potential occurs, resulting in reduction of NPR1 to a monomeric form. Monomeric NPR1 accumulates in the nucleus and activates gene expression. Inhibition of NPR1 reduction prevents defense gene expression, whereas mutation of Cys82 or Cys216 in NPR1 leads to constitutive monomerization, nuclear localization of the mutant proteins, and defense gene expression. These data provide a missing link between accumulation of SA and activation of NPR1 in the SAR signaling pathway.
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Affiliation(s)
- Zhonglin Mou
- Developmental, Cell, and Molecular Biology Group, Department of Biology, P.O. Box 91000, Duke University, Durham, NC 27708, USA
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331
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Lillig CH, Potamitou A, Schwenn JD, Vlamis-Gardikas A, Holmgren A. Redox regulation of 3'-phosphoadenylylsulfate reductase from Escherichia coli by glutathione and glutaredoxins. J Biol Chem 2003; 278:22325-30. [PMID: 12682041 DOI: 10.1074/jbc.m302304200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inorganic sulfate (SO42-, S+VI) is reduced in vivo to sulfite (SO32-, S+IV) via phosphoadenylylsulfate (PAPS) reductase. Escherichia coli lacking glutathione reductase and glutaredoxins (gor-grxA-grxB-grxC-) barely grows on sulfate. We found that incubation of PAPS reductase with oxidized glutathione leads to enzyme inactivation with simultaneous formation of a mixed disulfide between glutathione and the active site Cys-239. A newly developed method based on thiol-specific fluorescent alkylation and gel electrophoresis showed that glutathionylated PAPS reductase is reduced by glutaredoxins via a monothiol mechanism. This glutathionylated species was also observed in poorly growing gor-grxA-grxB-grxC- cells expressing inactive glutaredoxin 2 (Grx2) C9S/C12S. However, it was absent in better growing cells expressing monothiol Grx2 C12S or wild type Grx2. Reversible glutathionylation may thus regulate the activity of PAPS reductase in vivo.
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Affiliation(s)
- Christopher Horst Lillig
- Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles Väg 2, 17177 Stockholm, Sweden
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332
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Salmeen A, Andersen JN, Myers MP, Meng TC, Hinks JA, Tonks NK, Barford D. Redox regulation of protein tyrosine phosphatase 1B involves a sulphenyl-amide intermediate. Nature 2003; 423:769-73. [PMID: 12802338 DOI: 10.1038/nature01680] [Citation(s) in RCA: 706] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2003] [Accepted: 04/07/2003] [Indexed: 11/09/2022]
Abstract
The second messenger hydrogen peroxide is required for optimal activation of numerous signal transduction pathways, particularly those mediated by protein tyrosine kinases. One mechanism by which hydrogen peroxide regulates cellular processes is the transient inhibition of protein tyrosine phosphatases through the reversible oxidization of their catalytic cysteine, which suppresses protein dephosphorylation. Here we describe a structural analysis of the redox-dependent regulation of protein tyrosine phosphatase 1B (PTP1B), which is reversibly inhibited by oxidation after cells are stimulated with insulin and epidermal growth factor. The sulphenic acid intermediate produced in response to PTP1B oxidation is rapidly converted into a previously unknown sulphenyl-amide species, in which the sulphur atom of the catalytic cysteine is covalently linked to the main chain nitrogen of an adjacent residue. Oxidation of PTP1B to the sulphenyl-amide form is accompanied by large conformational changes in the catalytic site that inhibit substrate binding. We propose that this unusual protein modification both protects the active-site cysteine residue of PTP1B from irreversible oxidation to sulphonic acid and permits redox regulation of the enzyme by promoting its reversible reduction by thiols.
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Affiliation(s)
- Annette Salmeen
- Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
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333
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Abstract
Bacterial resistance to inorganic and organic mercury compounds (HgR) is one of the most widely observed phenotypes in eubacteria. Loci conferring HgR in Gram-positive or Gram-negative bacteria typically have at minimum a mercuric reductase enzyme (MerA) that reduces reactive ionic Hg(II) to volatile, relatively inert, monoatomic Hg(0) vapor and a membrane-bound protein (MerT) for uptake of Hg(II) arranged in an operon under control of MerR, a novel metal-responsive regulator. Many HgR loci encode an additional enzyme, MerB, that degrades organomercurials by protonolysis, and one or more additional proteins apparently involved in transport. Genes conferring HgR occur on chromosomes, plasmids, and transposons and their operon arrangements can be quite diverse, frequently involving duplications of the above noted structural genes, several of which are modular themselves. How this very mobile and plastic suite of proteins protects host cells from this pervasive toxic metal, what roles it has in the biogeochemical cycling of Hg, and how it has been employed in ameliorating environmental contamination are the subjects of this review.
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Affiliation(s)
- Tamar Barkay
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, NJ, USA.
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334
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Schembri MA, Hjerrild L, Gjermansen M, Klemm P. Differential expression of the Escherichia coli autoaggregation factor antigen 43. J Bacteriol 2003; 185:2236-42. [PMID: 12644494 PMCID: PMC151503 DOI: 10.1128/jb.185.7.2236-2242.2003] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2002] [Accepted: 12/26/2002] [Indexed: 11/20/2022] Open
Abstract
Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox sensor OxyR. Here we used mutant versions of OxyR that are locked in either the reduced or the oxidized form as well as the addition of a simple redox-changing chemical to show that the redox state of OxyR influences Ag43 expression. Furthermore, the redox state of OxyR influences the biofilm-forming potential of E. coli. Finally, we demonstrated that Ag43-mediated cell aggregation confers significant protection against hydrogen peroxide killing.
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Affiliation(s)
- Mark A Schembri
- Microbial Adhesion Group, BioCentrum-DTU, Technical University of Denmark, DK-2800 Lyngby, Denmark
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335
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Wallecha A, Correnti J, Munster V, van der Woude M. Phase variation of Ag43 is independent of the oxidation state of OxyR. J Bacteriol 2003; 185:2203-9. [PMID: 12644490 PMCID: PMC151510 DOI: 10.1128/jb.185.7.2203-2209.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2002] [Accepted: 01/14/2003] [Indexed: 11/20/2022] Open
Abstract
OxyR is a DNA binding protein that differentially regulates a cell's response to hydrogen peroxide-mediated oxidative stress. We previously reported that the reduced form of OxyR is sufficient for repression of transcription of agn43 from unmethylated template DNA, which is essential for deoxyadenosine methylase (Dam)- and OxyR-dependent phase variation of agn43. Here we provide evidence that the oxidized form of OxyR [OxyR(ox)] also represses agn43 transcription. In vivo, we found that exogenous addition of hydrogen peroxide, sufficient to oxidize OxyR, did not affect the expression of agn43. OxyR(ox) repressed in vitro transcription but only from an unmethylated agn43 template. The -10 sequence of the promoter and three Dam target sequences were protected in an in vitro DNase I footprint assay by OxyR(ox). Furthermore, OxyR(ox) bound to the agn43 regulatory region DNA with an affinity similar to that for the regulatory regions of katG and oxyS, which are activated by OxyR(ox), indicating that binding at agn43 can occur at biologically relevant concentrations. OxyR-dependent regulation of Ag43 expression is therefore unusual in firstly that OxyR binding at agn43 is dependent on the methylation state of Dam target sequences in its binding site and secondly that OxyR-dependent repression appears to be independent of hydrogen-peroxide mediated oxidative stress and the oxidation state of OxyR.
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Affiliation(s)
- Anu Wallecha
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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336
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Gardner AM, Gessner CR, Gardner PR. Regulation of the nitric oxide reduction operon (norRVW) in Escherichia coli. Role of NorR and sigma54 in the nitric oxide stress response. J Biol Chem 2003; 278:10081-6. [PMID: 12529359 DOI: 10.1074/jbc.m212462200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric oxide (NO) induces NO-detoxifying enzymes in Escherichia coli suggesting sensitive mechanisms for coordinate control of NO defense genes in response to NO stress. Exposure of E. coli to sub-micromolar NO levels under anaerobic conditions rapidly induced transcription of the NO reductase (NOR) structural genes, norV and norW, as monitored by lac gene fusions. Disruption of rpoN (sigma(54)) impaired the NO-mediated induction of norV and norW transcription and NOR expression, whereas disruption of the upstream regulatory gene, norR, completely ablated NOR induction. NOR inducibility was restored to NorR null mutants by expressing NorR in trans. Furthermore, an internal deletion of the N-terminal domain of NorR activated NOR expression independent of NO exposure. Neither NorR nor sigma(54) was essential for NO-mediated induction of the NO dioxygenase (flavohemoglobin) encoded by hmp. However, elevated NOR activity inhibited NO dioxygenase induction, and, in the presence of dioxygen, NO dioxygenase inhibited norV induction by NO. The results demonstrate the role of NorR as a sigma(54)-dependent regulator of norVW expression. A role for the NorR N-terminal domain as a transducer or sensor for NO is suggested.
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Affiliation(s)
- Anne M Gardner
- Division of Critical Care Medicine, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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337
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Nathan C. Specificity of a third kind: reactive oxygen and nitrogen intermediates in cell signaling. J Clin Invest 2003. [DOI: 10.1172/jci200318174] [Citation(s) in RCA: 339] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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338
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Sun J, Xu L, Eu JP, Stamler JS, Meissner G. Nitric oxide, NOC-12, and S-nitrosoglutathione modulate the skeletal muscle calcium release channel/ryanodine receptor by different mechanisms. An allosteric function for O2 in S-nitrosylation of the channel. J Biol Chem 2003; 278:8184-9. [PMID: 12509428 DOI: 10.1074/jbc.m211940200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The skeletal muscle Ca(2+) release channel/ryanodine receptor (RyR1) contains approximately 50 thiols per subunit. These thiols have been grouped according to their reactivity/responsiveness toward NO, O(2), and glutathione, but the molecular mechanism enabling redox active molecules to modulate channel activity is poorly understood. In the case of NO, very low concentrations (submicromolar) activate RyR1 by S-nitrosylation of a single cysteine residue (Cys-3635), which resides within a calmodulin binding domain. S-Nitrosylation of Cys-3635 only takes place at physiological tissue O(2) tension (pO(2); i.e. approximately 10 mm Hg) but not at pO(2) approximately 150 mm Hg. Two explanations have been offered for the loss of RyR1 responsiveness to NO at ambient pO(2), i.e. Cys-3635 is oxidized by O(2) versus O(2) subserves an allosteric function (Eu, J. P., Sun, J. H., Xu, L., Stamler, J. S., and Meissner, G. (2000) Cell 102, 499-509). Here we report that the NO donors NOC-12 and S-nitrosoglutathione both activate RyR1 by release of NO but do so independently of pO(2). Moreover, NOC-12 activates the channel by S-nitrosylation of Cys-3635 and thereby reverses channel inhibition by calmodulin. In contrast, S-nitrosoglutathione activates RyR1 by oxidation and S-nitrosylation of thiols other than Cys-3635 (and calmodulin is not involved). Our results suggest that the effect of pO(2) on RyR1 S-nitrosylation is exerted through an allosteric mechanism.
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Affiliation(s)
- Junhui Sun
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599-7260, USA
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339
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Soberman RJ. Series Introduction: The expanding network of redox signaling: new observations, complexities, and perspectives. J Clin Invest 2003. [DOI: 10.1172/jci200318099] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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340
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Marnett LJ, Riggins JN, West JD. Endogenous generation of reactive oxidants and electrophiles and their reactions with DNA and protein. J Clin Invest 2003; 111:583-93. [PMID: 12618510 PMCID: PMC151910 DOI: 10.1172/jci18022] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Lawrence J Marnett
- Department of Biochemistry, Vanderbilt University School of Medicine, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Nashville, Tennessee, USA.
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341
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Marnett LJ, Riggins JN, West JD. Endogenous generation of reactive oxidants and electrophiles and their reactions with DNA and protein. J Clin Invest 2003. [DOI: 10.1172/jci200318022] [Citation(s) in RCA: 320] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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342
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Nathan C. Specificity of a third kind: reactive oxygen and nitrogen intermediates in cell signaling. J Clin Invest 2003; 111:769-78. [PMID: 12639979 PMCID: PMC153776 DOI: 10.1172/jci18174] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Carl Nathan
- Department of Microbiology and Immunology and Graduate Programs in Immunology and Molecular Biology, Weill Medical College of Cornell University, New York, New York 10021, USA.
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343
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Soberman RJ. The expanding network of redox signaling: new observations, complexities, and perspectives. J Clin Invest 2003; 111:571-4. [PMID: 12618508 PMCID: PMC151913 DOI: 10.1172/jci18099] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Roy J Soberman
- Renal Unit and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
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344
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Ahn SG, Thiele DJ. Redox regulation of mammalian heat shock factor 1 is essential for Hsp gene activation and protection from stress. Genes Dev 2003; 17:516-28. [PMID: 12600944 PMCID: PMC195992 DOI: 10.1101/gad.1044503] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The activation of eukaryotic heat shock protein (Hsp) gene expression occurs in response to a wide variety of cellular stresses including heat shock, hydrogen peroxide, uncoupled oxidative phosphorylation, infection, and inflammation. Biochemical and genetic studies have clearly demonstrated critical roles for mammalian heat shock factor 1 (HSF1) in stress-inducible Hsp gene expression, resistance to stress-induced programmed cell death, extra-embryonic development, and other biological functions. Activation of mammalian Hsp gene expression involves the stress-inducible conversion of HSF1 from the inactive monomer to the DNA-binding competent homotrimer. Although Hsp activation is a central conserved process in biology, the precise mechanisms for stress sensing and signaling to activate HSF1, and the mechanisms by which many distinct stresses activate HSF1, are poorly understood. In this report we demonstrate that recombinant mammalian HSF1 directly senses both heat and hydrogen peroxide to assemble into a homotrimer in a reversible and redox-regulated manner. The sensing of both stresses requires two cysteine residues within the HSF1 DNA-binding domain that are engaged in redox-sensitive disulfide bonds. HSF1 derivatives in which either or both cysteines were mutated are defective in stress-inducible trimerization and DNA binding, stress-inducible nuclear translocation and Hsp gene trans-activation, and in the protection of mouse cells from stress-induced apoptosis. This redox-dependent activation of HSF1 by heat and hydrogen peroxide establishes a common mechanism in the stress activation of Hsp gene expression by mammalian HSF1.
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Affiliation(s)
- Sang-Gun Ahn
- Department of Biological Chemistry, The University of Michigan Medical School, Ann Arbor, Michigan 48109-0606, USA
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345
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Chai YC, Hoppe G, Sears J. Reversal of protein S-glutathiolation by glutaredoxin in the retinal pigment epithelium. Exp Eye Res 2003; 76:155-9. [PMID: 12565802 DOI: 10.1016/s0014-4835(02)00309-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Protein cysteines can serve both sensory and activation roles in the regulation of protein function. The modulation of mixed disulfides with glutathione may promise to be a broad mechanism of redox signalling. Using both protein extract and intact RPE cells, we have generated covalent adduction of glutathione to protein cysteines and further show that glutaredoxin (Grx-1) is able to remove glutathione from protein S-glutathiolated substrates. Our data demonstrate that glutathione can modify a wide range of RPE proteins in intact cells, but that the reversal of this process--deglutathiolation and thiol bond restoration--may require a specific catalytic reaction with glutaredoxin. More generally, our experiments support the hypothesis that glutathione can non-specifically become adducted to protein cysteines during oxidative stress, but that the specific, functional reconstitution of protein thiols depends on recognition by an oxidoreductase such as glutaredoxin. This concept offers the idea that redox signalling involves both adduction of a non-specific non-protein reducing equivalent such as glutathione and specific protein based removal by glutaredoxin.
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Affiliation(s)
- Yuh-Cherng Chai
- Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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346
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Abstract
Semaphorins constitute one of the largest families of repulsive and attractive growth cone guidance proteins. They affect the growth cone's actin cytoskeleton through interactions with receptor complexes composed of ligand-binding, signal-transducing, and modulatory subunits. Our understanding of the intracellular signal transduction machinery linking semaphorins to actin dynamics is limited; however, recent advances provide a more comprehensive view of the molecular basis of neuronal semaphorin signaling.
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Affiliation(s)
- R Jeroen Pasterkamp
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, USA.
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347
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Abstract
Redox-sensitive transcription factors such as the E. coli OxyR and S. cerevisiae Yap1, are activated by conformational changes that stem from the post-translational modification of reactive protein thiols. Recent studies provide new insights on how different agents that cause redox stress mediate the activation of transcription through distinct and specific pathways.
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Affiliation(s)
- George Georgiou
- Department of Chemical Engineering, Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA.
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348
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Delaunay A, Pflieger D, Barrault MB, Vinh J, Toledano MB. A thiol peroxidase is an H2O2 receptor and redox-transducer in gene activation. Cell 2002; 111:471-81. [PMID: 12437921 DOI: 10.1016/s0092-8674(02)01048-6] [Citation(s) in RCA: 652] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The Yap1 transcription factor regulates hydroperoxide homeostasis in S. cerevisiae. Yap1 is activated by oxidation when hydroperoxide levels increase. We show that Yap1 is not directly oxidized by hydroperoxide. We identified the glutathione peroxidase (GPx)-like enzyme Gpx3 as a second component of the pathway, serving the role of sensor and transducer of the hydroperoxide signal to Yap1. When oxidized by H2O2, Gpx3 Cys36 bridges Yap1 Cys598 by a disulfide bond. This intermolecular disulfide bond is then resolved into a Yap1 intramolecular disulfide bond, the activated form of the regulator. Thioredoxin turns off the pathway by reducing both sensor and regulator. These data reveal a redox-signaling function for a GPx-like enzyme and elucidate a eukaryotic hydroperoxide-sensing mechanism. Gpx3 is thus a hydroperoxide receptor and redox-transducer.
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Affiliation(s)
- Agnès Delaunay
- Laboratoire Stress Oxydants et Cancers, SBGM, DBJC, CEA-Saclay, 91191 Gif-sur-Yvette, Cedex, France
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349
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Helmann JD. OxyR: a molecular code for redox sensing? SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2002; 2002:pe46. [PMID: 12419849 DOI: 10.1126/stke.2002.157.pe46] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Helmann discusses the controversy surrounding the activation of the bacterial redox-regulated transcription factor OxyR. Evidence from different sources, including crystallographic data, has led to opposing models for the chemical changes that activate OxyR. Is it an intramolecular disulfide-linkage? Is it oxidation of a single cysteine residue to a sulfenic acid? Are there different active forms depending on the type of cysteine modification: intramolecular disulfide bond, sulfenic acid, S-nitrosothiol, or mixed disulfide with glutathione? These issues are discussed in the broader context of transcriptional regulation and how particular regulators may activate distinct genetic programs depending on the precise state of the regulator produced in response to environmental cues.
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Affiliation(s)
- John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA.
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