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The Functional Role Of Cysteine Residues For C-Abl Kinase Activity., Amanda Leonberg, Yuh-Cherng Chai
The Functional Role Of Cysteine Residues For C-Abl Kinase Activity., Amanda Leonberg, Yuh-Cherng Chai
Yuh-Cherng Chai
S-glutathionylation, the formation of mixed disulfides of glutathione with cysteine residues of proteins, is a broadly observed physiological modification that occurs in response to oxidative stress. Since cysteine residues are particularly susceptible to oxidative modification by reactive oxygen species, S-glutathionylation can protect proteins from irreversible oxidation. In this study, we show that the kinase activity of the non-receptor tyrosine kinase c-Abl is inhibited by in vitro thiol modification; specifically, the cysteine residues of c-Abl are modified by S-glutathionylation and by thiol alkylating agents such as 4-acetamido-4′-maleimidylstilbene-2,2′-disulfonic acid and N-ethylmaleimide. Modification of cysteine residues of c-Abl tyrosine kinase using glutathione disulfide …
Reversal Of Protein S-Glutathiolation By Glutaredoxin In The Retinal Pigment Epithelium., Yuh-Cherng Chai, George Hoppe, Jonathan Sears
Reversal Of Protein S-Glutathiolation By Glutaredoxin In The Retinal Pigment Epithelium., Yuh-Cherng Chai, George Hoppe, Jonathan Sears
Yuh-Cherng Chai
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 …