title: Reversal of protein S-glutathiolation by glutaredoxin in the retinal pigment epithelium.
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.
authors.affiliation: Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Yuh-Cherng
authors.initials: YC
authors.lastname: Chai
authors.forename: George
authors.initials: G
authors.lastname: Hoppe
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sears
mesh_terms: D015153:Blotting, Western; D018929:Cell Culture Techniques / Q000379:methods; D054477:Glutaredoxins; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D010088:Oxidoreductases / Q000494:pharmacology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017293:Protein S / Q000187:drug effects / Q000378:metabolism*; D011506:Proteins / Q000494:pharmacology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: C516005:GLRX protein, human; D054477:Glutaredoxins; D017293:Protein S; D011506:Proteins; D010088:Oxidoreductases; D005978:Glutathione