451
|
López-Martín MC, Romero LC, Gotor C. Cytosolic cysteine in redox signaling. PLANT SIGNALING & BEHAVIOR 2008; 3:880-1. [PMID: 19704851 PMCID: PMC2637515 DOI: 10.4161/psb.3.10.6289] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 05/19/2008] [Indexed: 05/22/2023]
Abstract
CYSTEINE BIOSYNTHESIS IN PLANTS TAKES PLACE IN THE THREE CELLULAR COMPARTMENTS WITH AUTONOMOUS PROTEIN BIOSYNTHESIS MACHINERY: cytosol, plastids and mitochondria. This sulfur-containing molecule is synthesized sequentially in these compartments by two enzymatic families, the serine acetyltransferases and the O-acetylserine(thiol) lyases. Each family consists of several isoforms that differ in subcellular localization and abundance. Why so many isoforms are required in plant cell for cysteine biosynthesis has remained unknown to date. The characterization of gene-specific knockout mutants has started to address this question. In our recent work, we have performed a detailed analysis of the Arabidopsis oas-a1 null mutant and showed that the antioxidant capacity of the cytosol is compromised, highlighting the contribution of cytosolic Cys in redox signaling.
Collapse
|
452
|
Gertz M, Fischer F, Wolters D, Steegborn C. Activation of the lifespan regulator p66Shc through reversible disulfide bond formation. Proc Natl Acad Sci U S A 2008; 105:5705-9. [PMID: 18413607 PMCID: PMC2311372 DOI: 10.1073/pnas.0800691105] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Indexed: 11/18/2022] Open
Abstract
Cell fate and organismal lifespan are controlled by a complex signaling network whose dysfunction can cause a variety of aging-related diseases. An important protection against these failures is cellular apoptosis, which can be induced by p66(Shc) in response to cellular stress. The precise mechanisms of p66(Shc) action and regulation and the function of the p66(Shc)-specific N terminus remain to be identified. Here, we show that the p66(Shc) N terminus forms a redox module responsible for apoptosis initiation, and that this module can be activated through reversible tetramerization by forming two disulfide bonds. Glutathione and thioredoxins can reduce and inactivate p66(Shc), resulting in a thiol-based redox sensor system that initiates apoptosis once cellular protection systems cannot cope anymore with cellular stress.
Collapse
|
453
|
Abstract
Monothiol glutaredoxins with the CGFS sequence at the active site are widespread among prokaryotes and eukaryotes. Two subclasses exist, those with a single glutaredoxin domain and those with a thioredoxin-like region followed by one or more glutaredoxin domains. Studies in Saccharomyces cerevisiae have demonstrated the role of the Grx5 protein in the biogenesis of iron-sulfur clusters. Grx5 homologues in other eukaryotes could carry out similar functions. Two S. cerevisiae monothiol glutaredoxins with the thioredoxin-like extension, Grx3 and Grx4, are modulators of the transcriptional activator Aft1, which regulates iron uptake in yeast. The human PICOT protein is a Grx3/Grx4 homologue with the same hybrid primary structure that regulates protein kinase C activity and may participate in physiological processes such as control of cardiac function. Therefore, monothiol glutaredoxins share a common basic structural motif and biochemical mechanism of action, while participating in a diversity of cellular functions as protein redox regulators.
Collapse
|
454
|
Balmer Y, Vensel WH, Cai N, Manieri W, Schürmann P, Hurkman WJ, Buchanan BB. A complete ferredoxin/thioredoxin system regulates fundamental processes in amyloplasts. Proc Natl Acad Sci U S A 2006; 103:2988-93. [PMID: 16481623 PMCID: PMC1413819 DOI: 10.1073/pnas.0511040103] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A growing number of processes throughout biology are regulated by redox via thiol-disulfide exchange. This mechanism is particularly widespread in plants, where almost 200 proteins have been linked to thioredoxin (Trx), a widely distributed small regulatory disulfide protein. The current study extends regulation by Trx to amyloplasts, organelles prevalent in heterotrophic plant tissues that, among other biosynthetic activities, catalyze the synthesis and storage of copious amounts of starch. Using proteomics and immunological methods, we identified the components of the ferredoxin/Trx system (ferredoxin, ferredoxin-Trx reductase, and Trx), originally described for chloroplasts, in amyloplasts isolated from wheat starchy endosperm. Ferredoxin is reduced not by light, as in chloroplasts, but by metabolically generated NADPH via ferredoxin-NADP reductase. However, once reduced, ferredoxin appears to act as established for chloroplasts, i.e., via ferredoxin-Trx reductase and a Trx (m-type). A proteomics approach in combination with affinity chromatography and a fluorescent thiol probe led to the identification of 42 potential Trx target proteins, 13 not previously recognized, including a major membrane transporter (Brittle-1 or ADP-glucose transporter). The proteins function in a range of processes in addition to starch metabolism: biosynthesis of lipids, amino acids, and nucleotides; protein folding; and several miscellaneous reactions. The results suggest a mechanism whereby light is initially recognized as a thiol signal in chloroplasts, then as a sugar during transit to the sink, where it is converted again to a thiol signal. In this way, amyloplast reactions in the grain can be coordinated with photosynthesis taking place in leaves.
Collapse
|
455
|
Zhao R, Xiang N, Domann FE, Zhong W. Expression of p53 enhances selenite-induced superoxide production and apoptosis in human prostate cancer cells. Cancer Res 2006; 66:2296-304. [PMID: 16489034 PMCID: PMC1435866 DOI: 10.1158/0008-5472.can-05-2216] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although the anticancer effects of selenium have been shown in clinical, preclinical, and laboratory studies, the underlying mechanism(s) remains unclear. Our previous study showed that sodium selenite induced LNCaP human prostate cancer cell apoptosis in association with production of reactive oxygen species, alteration of cell redox state, and mitochondrial damage. In the present study, we showed that selenite-induced apoptosis was superoxide mediated and p53 dependent via mitochondrial pathways. In addition, we also showed that superoxide production by selenite was p53 dependent. Our study showed that wild-type p53-expressing LNCaP cells were more sensitive to selenite-induced apoptosis than p53-null PC3 cells. Selenite treatment resulted in high levels of superoxide production in LNCaP cells but only low levels in PC3 cells. LNCaP cells also showed sequential increases in levels of phosphorylated p53 (serine 15), total p53, Bax, and p21(Waf1) proteins following selenite treatment. The effects of selenite were suppressed by pretreatment with a synthetic superoxide dismutase mimic or by knockdown of p53 via RNA interference. LNCaP cells treated with selenite also showed p53 translocation to mitochondria, cytochrome c release into the cytosol, and activation of caspase-9. On the other hand, restoration of wild-type p53 expression in PC3 cells increased cellular sensitivity to selenite and resulted in increased superoxide production, caspase-9 activation, and apoptosis following selenite treatment. These results suggest that selenite induces apoptosis by producing superoxide to activate p53 and to induce p53 mitochondrial translocation. Activation of p53 in turn synergistically enhances superoxide production and apoptosis induced by selenite.
Collapse
Key Words
- apoptosis
- mitochondria
- p53 tumor suppressor
- prostate cancer
- redox regulation
- selenite
- superoxide
- cuznsod, copper and zinc-containing superoxide dismutase
- h2ax, phosphorylated histone h2ax (serine 139)
- gsh, reduced glutathione
- gssg, glutathione disulfide
- gpx, glutathione peroxidase
- mnsod, manganese-containing superoxide dismutase
- mntmpyp, manganese (iii) tetrakis (n-methyl-2-pyridyl) porphyrin
- moi, multiplicity of infectivity
- mtt, 3-[4,5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2 tetrazolium bromide
- rlu, relative light unit
- ros, reactive oxygen species
- sel, selenite
- sirna, small interfering rna
- sod, superoxide dismutase
Collapse
|
456
|
Mikkelsen R, Mutenda KE, Mant A, Schürmann P, Blennow A. Alpha-glucan, water dikinase (GWD): a plastidic enzyme with redox-regulated and coordinated catalytic activity and binding affinity. Proc Natl Acad Sci U S A 2005; 102:1785-90. [PMID: 15665090 PMCID: PMC547843 DOI: 10.1073/pnas.0406674102] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Indexed: 11/18/2022] Open
Abstract
The recently discovered potato tuber (Solanum tuberosum) alpha-glucan, water dikinase (GWD) (formerly known as R1) catalyzes the phosphorylation of starch by a dikinase-type reaction mechanism in which the beta-phosphate of ATP is transferred to either the C-6 or the C-3 position of the glucosyl residue of starch. In the present study, we found that the GWD enzyme is inactive in the oxidized form, which is accompanied by the formation of a specific intramolecular disulfide bond as determined by disulfide-linked peptide mapping. The regulatory properties of this disulfide linkage were confirmed by site-directed mutagenesis studies. Both reduced thioredoxin (Trx) f and Trx m from spinach leaves reduced and activated oxidized GWD at very low concentrations, with Trx f being the more efficient, yielding an S0.5 value of 0.4 microM. Interestingly, GWD displays a reversible and selective binding to starch granules depending on the illumination state of the plant. Here we show that starch granule-bound GWD isolated from dark-adapted plants exists in the inactive, oxidized form, which is capable of reactivation upon treatment with reduced Trx. Furthermore, the soluble form of GWD was found in its fully reduced state, providing evidence of a Trx-controlled regulation mechanism linking enzymatic activity and specific binding affinities of a protein to an intracellular surface. The regulatory site sequence, CFATC, of potato GWD is conserved in chloroplast-targeted GWDs from other species, suggesting an overall redox regulation of the GWD enzyme.
Collapse
|
457
|
van Lis R, Atteia A. Control of Mitochondrial Function via Photosynthetic Redox Signals. PHOTOSYNTHESIS RESEARCH 2004; 79:133-48. [PMID: 16228388 DOI: 10.1023/b:pres.0000015409.14871.68] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In photosynthetic cells, mitochondrial respiration is of major importance not only in the dark but also in the light. Important progress has been made in our understanding of the roles played by mitochondria in light. The light signal is likely to reach cellular compartments such as the mitochondrion and the nucleus via different chloroplast-originated redox messages. The potential involvement of these messages in the regulation of mitochondrial biogenesis and activity by light is discussed in view of the available experimental data.
Collapse
|
458
|
Zeilstra-Ryalls JH, Kaplan S. Oxygen intervention in the regulation of gene expression: the photosynthetic bacterial paradigm. Cell Mol Life Sci 2004; 61:417-36. [PMID: 14999403 PMCID: PMC11138845 DOI: 10.1007/s00018-003-3242-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The means by which oxygen intervenes in gene expression has been examined in considerable detail in the metabolically versatile bacterium Rhodobacter sphaeroides. Three regulatory systems are now known in this organism, which are used singly and in combination to modulate genes in response to changing oxygen availability. The outcome of these regulatory events is that the molecular machinery is present for the cell to obtain energy by means that are best suited to prevailing conditions, while at the same time maintaining cellular redox balance. Here, we explore the dangers associated with molecular oxygen relative to the various metabolisms used by R. sphaeroides, and then present the most recent findings regarding the features and operation of each of the three regulatory systems which collectively mediate oxygen control in this organism.
Collapse
|
459
|
Abstract
In the current view of most biochemists and physiologists, the role of L-ascorbic acid (AA) in cell metabolism would be more or less confined to the scavenging of reactive oxygen species. Nevertheless, many data have been collected in our and other laboratories concerning the involvement of AA in many different aspects of cell metabolism. At the present time the molecular sites of action of AA have not been completely elucidated, but recent findings on the specific requirement of AA for the activity of several 2-oxoacid-dependent dioxygenases involved in cell signalling and the activation of transcription factors open new fascinating perspectives for further research.
Collapse
|
460
|
Hoyos B, Imam A, Chua R, Swenson C, Tong GX, Levi E, Noy N, Hämmerling U. The cysteine-rich regions of the regulatory domains of Raf and protein kinase C as retinoid receptors. J Exp Med 2000; 192:835-45. [PMID: 10993914 PMCID: PMC2193291 DOI: 10.1084/jem.192.6.835] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Vitamin A and its biologically active derivatives, the retinoids, are recognized as key regulators of vertebrate development, cell growth, and differentiation. Although nuclear receptors have held the attention since their discovery a decade ago, we report here on serine/threonine kinases as a new class of retinoid receptors. The conserved cysteine-rich domain of the NH(2)-terminal regulatory domains of cRaf-1, as well as several select domains of the mammalian protein kinase C (PKC) isoforms alpha, delta, zeta, and mu, the Drosophila and yeast PKCs, were found to bind retinol with nanomolar affinity. The biological significance was revealed in the alternate redox activation pathway of these kinases. Retinol served as a cofactor to augment the activation of both cRaf and PKC alpha by reactive oxygen, whereas the classical receptor-mediated pathway was unaffected by the presence or absence of retinol. We propose that bound retinol, owing to its electron transfer capacity, functions as a tag to enable the efficient and directed redox activation of the cRaf and PKC families of kinases.
Collapse
|
461
|
Takagi Y, Mitsui A, Nishiyama A, Nozaki K, Sono H, Gon Y, Hashimoto N, Yodoi J. Overexpression of thioredoxin in transgenic mice attenuates focal ischemic brain damage. Proc Natl Acad Sci U S A 1999; 96:4131-6. [PMID: 10097175 PMCID: PMC22432 DOI: 10.1073/pnas.96.7.4131] [Citation(s) in RCA: 266] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Thioredoxin (TRX) plays important biological roles both in intra- and extracellular compartments, including in regulation of various intracellular molecules via thiol redox control. We produced TRX overexpressing mice and confirmed that there were no anatomical and physiological differences between wild-type (WT) mice and TRX transgenic (Tg) mice. In the present study we subjected mice to focal brain ischemia to shed light on the role of TRX in brain ischemic injury. At 24 hr after middle cerebral artery occlusion, infarct areas and volume were significantly smaller in Tg mice than in WT mice. Moreover neurological deficit was ameliorated in Tg mice compared with WT mice. Protein carbonyl content, a marker of cellular protein oxidation, in Tg mice showed less increase than did that of WT mice after the ischemic insult. Furthermore, c-fos expression in Tg mice was stronger than in WT mice 1 hr after ischemia. Our results suggest that transgene expression of TRX decreased ischemic neuronal injury and that TRX and the redox state modified by TRX play a crucial role in brain damage during stroke.
Collapse
|
462
|
Jacquot JP, Lancelin JM, Meyer Y. Thioredoxins: structure and function in plant cells. THE NEW PHYTOLOGIST 1997; 136:543-570. [PMID: 33863109 DOI: 10.1046/j.1469-8137.1997.00784.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Thioredoxins are ubiquitous small-molecular-weight proteins (typically 100-120 amino-acid residues) containing an extremely reactive disulphide bridge with a highly conserved sequence -Cys-Gly(Ala/Pro)-Pro-Cys-. In bacteria and animal cells, thioredoxins participate in multiple reactions which require reduction of disulphide bonds on selected target proteins/ enzymes. There is now ample biochemical evidence that thioredoxins exert very specific functions in plants, the best documented being the redox regulation of chloroplast enzymes. Another area in which thioredoxins are believed to play a prominent role is in reserve protein mobilization during the process of germination. It has been discovered that thioredoxins constitute a large multigene family in plants with different-subcellular localizations, a unique feature in living cells so far. Evolutionary studies based on these molecules will be discussed, as well as the available biochemical and genetic evidence related to their functions in plant cells. Eukaryotic photosynthetic plant cells are also unique in that they possess two different reducing systems, one extrachloroplastic dependent on NADPH as an electron donor, and the other one chloroplastic, dependent on photoreduced ferredoxin. This review will examine in detail the latest progresses in the area of thioredoxin structural biology in plants, this protein being an excellent model for this purpose. The structural features of the reducing enzymes ferredoxin thioredoxin reductase and NADPH thioredoxin reductase will also be described. The properties of the target enzymes known so far in plants will be detailed with special emphasis on the structural features which make them redox regulatory. Based on sequence analysis, evidence will be presented that redox regulation of enzymes of the biosynthetic pathways first appeared in cyanobacteria possibly as a way to cope with the oxidants produced by oxygenic photosynthesis. It became more elaborate in the chloroplasts of higher plants where a co-ordinated functioning of the chloroplastic and extra chloroplastic metabolisms is required. CONTENTS Summary 543 I. Introduction 544 II. Thioredoxins from photosynthetic organisms as a structural model 545 III. Physiological functions 552 IV. The thioredoxin reduction systems 556 V. Structural aspects of target enzymes 558 VI. Concluding remarks 563 Acknowledgements 564 References 564.
Collapse
|
463
|
Hirota K, Matsui M, Iwata S, Nishiyama A, Mori K, Yodoi J. AP-1 transcriptional activity is regulated by a direct association between thioredoxin and Ref-1. Proc Natl Acad Sci U S A 1997; 94:3633-8. [PMID: 9108029 PMCID: PMC20492 DOI: 10.1073/pnas.94.8.3633] [Citation(s) in RCA: 636] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Thioredoxin (TRX) is a pleiotropic cellular factor that has thiol-mediated redox activity and is important in regulation of cellular processes, including proliferation, apoptosis, and gene expression. The activity of several transcription factors is posttranslationally altered by redox modification(s) of specific cysteine residue(s). One such factor is nuclear factor (NF)-kappa B, whose DNA-binding activity is markedly augmented by TRX treatment in vitro. Similarly, the DNA-binding activity of activator protein 1 (AP-1) is modified by a DNA repair enzyme, redox factor 1 (Ref-1), which is identical to a DNA repair enzyme, AP endonuclease. Ref-1 activity is in turn modulated by various redox-active compounds, including TRX. We here report the molecular cascade of redox regulation of AP-1 mediated by TRX and Ref-1. Phorbol 12-myristate 13 acetate efficiently translocated TRX into the HeLa cell nucleus where Ref-1 preexists. This process seems to be essential for AP-1 activation by redox modification because co-overexpression of TRX and Ref-1 in COS-7 cells potentiated AP-1 activity only after TRX was transported into the nucleus by phorbol 12-myristate 13 acetate treatment. To prove the direct active site-mediated association between TRX and Ref-1, we generated a series of substitution-mutant cysteine residues of TRX. In both an in vitro diamide-induced cross-linking study and an in vivo mammalian two-hybrid assay we proved that TRX can associate directly with Ref-1 in the nucleus; also, we demonstrated the requirement of cysteine residues in the TRX catalytic center for the potentiation of AP-1 activity. This report presents an example of a cascade in cellular redox regulation.
Collapse
|
464
|
Otsuji M, Kimura Y, Aoe T, Okamoto Y, Saito T. Oxidative stress by tumor-derived macrophages suppresses the expression of CD3 zeta chain of T-cell receptor complex and antigen-specific T-cell responses. Proc Natl Acad Sci U S A 1996; 93:13119-24. [PMID: 8917554 PMCID: PMC24056 DOI: 10.1073/pnas.93.23.13119] [Citation(s) in RCA: 239] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
One of the important mechanisms of immunosuppression in the tumor-bearing status has been attributed to the down-modulation of the CD3 zeta chain and its associated signaling molecules in T cells. Thus, the mechanism of the disappearance of CD3 zeta was investigated in tumor-bearing mice (TBM). The decrease of CD3 zeta was observed both in the cell lysate and intact cells. Direct interaction of T cells with macrophages from TBM (TBM-macrophages) induced the decrease of CD3 zeta, and depletion of macrophages rapidly restored the CD3 zeta expression. We found that treatment of such macrophages with N-acetylcysteine, known as antioxidant compound, prevented the decrease of CD3 zeta. Consistent with this result, the addition of oxidative reagents such as hydrogen peroxide and diamide induced the decrease of CD3 zeta expression in T cells. Consequently, the loss of CD3 zeta resulted in suppression of the antigen-specific T-cell response. These results demonstrate that oxidative stress by macrophages in tumor-bearing status induces abnormality of the T-cell receptor complex by cell interactions with T cells. Therefore, our findings suggest that oxidative stress contributes to the regulation of the expression and function of the T-cell receptor complex.
Collapse
|