20 S proteasome from Saccharomyces cerevisiae is responsive to redox modifications and is S-glutathionylated.
The 20 S proteasome core purified from Saccharomyces cerevisiae is inhibited by reduced glutathione (GSH), cysteine (Cys), or the GSH precursor gamma-glutamylcysteine. Chymotrypsin-like activity was more affected by GSH than trypsin-like activity, whereas the peptidylglutamyl-hydrolyzing activity (caspase-like) was not inhibited by GSH. Cys-sulfenic acid formation in the 20 S core ... was demonstrated by spectral characterization of the Cys-S(O)-4-nitrobenzo-2-oxa-1,3-diazole adduct, indicating that 20 S proteasome Cys residues might react with reduced sulfhydryls (GSH, Cys, and gamma-glutamylcysteine) through the oxidized Cys-sulfenic acid form. S-Glutahionylation of the 20 S core was demonstrated in vitro by GSH-biotin incorporation and by decreased alkylation with monobromobimane. Compounds such as N-ethylmaleimide (-S-sulfhydril H alkylating), dimedone (-SO sulfenic acid H reactant), or 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (either -SH or -SOH reactant) highly inhibited proteasomal chymotrypsin-like activity. In vivo experiments revealed that 20 S proteasome extracted from H(2)O(2)-treated cells showed decreased chymotrypsin-like activity accompanied by S-glutathionylation as demonstrated by GSH release from the 20 S core after reduction with NaBH(4). Moreover, cells pretreated with H(2)O(2) showed decreased reductive capacity assessed by determination of the GSH/oxidized glutathione ratio and increased protein carbonyl levels. The present results indicate that at the physiological level the yeast 20 S proteasome is regulated by its sulfhydryl content, thereby coupling intracellular redox signaling to proteasome-mediated proteolysis.
Mesh Terms:
Bicyclo Compounds, Cell Survival, Chelating Agents, Cysteine, Cysteine Endopeptidases, Dithiothreitol, Fluorescent Dyes, Glutathione, Hydrogen Peroxide, Multienzyme Complexes, Oxidants, Oxidation-Reduction, Pentetic Acid, Proteasome Endopeptidase Complex, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction, Sulfenic Acids, Sulfhydryl Compounds, Sulfhydryl Reagents
Bicyclo Compounds, Cell Survival, Chelating Agents, Cysteine, Cysteine Endopeptidases, Dithiothreitol, Fluorescent Dyes, Glutathione, Hydrogen Peroxide, Multienzyme Complexes, Oxidants, Oxidation-Reduction, Pentetic Acid, Proteasome Endopeptidase Complex, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction, Sulfenic Acids, Sulfhydryl Compounds, Sulfhydryl Reagents
J. Biol. Chem.
Date: Jan. 03, 2003
PubMed ID: 12409293
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