| Role of glutaredoxin 2 and cytosolic thioredoxins in cysteinyl-based redox modification of the 20S proteasome. | |
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MedLine Citation:
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PMID: 18435761 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The yeast 20S proteasome is subject to sulfhydryl redox alterations, such as the oxidation of cysteine residues (Cys-SH) into cysteine sulfenic acid (Cys-SOH), followed by S-glutathionylation (Cys-S-SG). Proteasome S-glutathionylation promotes partial loss of chymotrypsin-like activity and post-acidic cleavage without alteration of the trypsin-like proteasomal activity. Here we show that the 20S proteasome purified from stationary-phase cells was natively S-glutathionylated. Moreover, recombinant glutaredoxin 2 removes glutathione from natively or in vitro S-glutathionylated 20S proteasome, allowing the recovery of chymotrypsin-like activity and post-acidic cleavage. Glutaredoxin 2 deglutathionylase activity was dependent on its entry into the core particle, as demonstrated by stimulating S-glutathionylated proteasome opening. Under these conditions, deglutathionylation of the 20S proteasome and glutaredoxin 2 degradation were increased when compared to non-stimulated samples. Glutaredoxin 2 fragmentation by the 20S proteasome was evaluated by SDS-PAGE and mass spectrometry, and S-glutathionylation was evaluated by either western blot analyses with anti-glutathione IgG or by spectrophotometry with the thiol reactant 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. It was also observed in vivo that glutaredoxin 2 was ubiquitinated in cellular extracts of yeast cells grown in glucose-containing medium. Other cytoplasmic oxido-reductases, namely thioredoxins 1 and 2, were also active in 20S proteasome deglutathionylation by a similar mechanism. These results indicate for the first time that 20S proteasome cysteinyl redox modification is a regulated mechanism coupled to enzymatic deglutathionylase activity. |
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Authors:
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Gustavo M Silva; Luis E S Netto; Karen F Discola; Gilberto M Piassa-Filho; Daniel C Pimenta; José A Bárcena; Marilene Demasi |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-04-23 |
Journal Detail:
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Title: The FEBS journal Volume: 275 ISSN: 1742-464X ISO Abbreviation: FEBS J. Publication Date: 2008 Jun |
Date Detail:
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Created Date: 2008-05-15 Completed Date: 2008-07-15 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101229646 Medline TA: FEBS J Country: England |
Other Details:
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Languages: eng Pagination: 2942-55 Citation Subset: IM |
Affiliation:
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Instituto Butantan, Laboratório de Bioquímica e Biofísica, São Paulo, Brazil, and Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil. |
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| MeSH Terms | |
Descriptor/Qualifier:
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Cloning, Molecular Cysteine / chemistry* Cytosol / metabolism* Gene Expression Regulation, Fungal* Glutaredoxins / metabolism, physiology* Glutathione / chemistry, metabolism Hydrolysis Models, Biological Oxidation-Reduction Proteasome Endopeptidase Complex / chemistry, metabolism* Saccharomyces cerevisiae / metabolism* Thioredoxins / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Glutaredoxins; 52-90-4/Cysteine; 52500-60-4/Thioredoxins; 70-18-8/Glutathione; EC 3.4.25.1/Proteasome Endopeptidase Complex |
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