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Full-Text Articles in Life Sciences
The Effect Of Oxidant And The Non-Oxidant Alteration Of Cellular Thiol Concentration On The Formation Of Protein Mixed-Disulfides In Hek 293 Cells, Jasen Lee Gilge, Michael Fisher, Yuh-Cherng Chai
The Effect Of Oxidant And The Non-Oxidant Alteration Of Cellular Thiol Concentration On The Formation Of Protein Mixed-Disulfides In Hek 293 Cells, Jasen Lee Gilge, Michael Fisher, Yuh-Cherng Chai
Yuh-Cherng Chai
Cellular molecules possess various mechanisms in responding to oxidant stress. In terms of protein responses, protein S-glutathionylation is a unique post-translational modification of protein reactive cysteines forming disulfides with glutathione molecules. This modification has been proposed to play roles in antioxidant, regulatory and signaling in cells under oxidant stress. Recently, the increased level of protein S-glutathionylation has been linked with the development of diseases. In this report, specific S-glutathionylated proteins were demonstrated in human embryonic kidney 293 cells treated with two different oxidative reagents: diamide and hydrogen peroxide. Diamide is a chemical oxidizing agent whereas hydrogen peroxide is a physiological …
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 …
Protein S-Glutathionylation In Retinal Pigment Epithelium Converts Heat Shock Protein 70 To An Active Chaperone., George Hoppe, Yuh-Cherng Chai, J. Crabb, Jonathan Sears
Protein S-Glutathionylation In Retinal Pigment Epithelium Converts Heat Shock Protein 70 To An Active Chaperone., George Hoppe, Yuh-Cherng Chai, J. Crabb, Jonathan Sears
Yuh-Cherng Chai
A disulfide bond between key redox-sensitive cysteine residues and glutathione is one mechanism by which redox related allosteric effectors can regulate protein structure and function. Here we test the hypothesis that glutaredoxin-1 (Grx-1), a member of the oxidoreductase family of enzymes, may be a critical component of redox-sensitive molecular switches by mediating reversible protein S-glutathionylation and enzymatic catalysis of thiol/disulfide exchange. Deglutathionylation of a 70 kDa protein by Grx-1 was detected using a monoclonal antibody specific to protein S-glutathionylation. Heat shock cognate protein 70 (Hsc70) was identified as a substrate of Grx-1 through mass spectrometry. Recombinant Hsc70 was glutathionylated in …
Endogenous Oxidoreductase Expression Is Induced By Aminoglycosides, George Hoppe, Yuh-Cherng Chai, Jonathan Sears
Endogenous Oxidoreductase Expression Is Induced By Aminoglycosides, George Hoppe, Yuh-Cherng Chai, Jonathan Sears
Yuh-Cherng Chai
Oxidoreductases such as glutaredoxin are a major class of enzymes that reversibly catalyze thiol-disulfide exchange reactions. Transfection experiments using geneticin (G418) selection to identify the specific protein S-thiolated substrates of glutaredoxin-1 (Grx-1) noted the curious phenomenon that nontransfected control cells treated with G418 had increased levels of Grx-1 expression. Varied concentrations of gentamicin, kanamycin, and hygromycin increased Grx-1 expression in a time- and dose-dependent fashion in human cultured retinal pigment epithelial cells. Reactive oxygen species formation after aminoglycoside exposure correlated directly to aminoglycoside treatment. Further indication that oxidation regulates Grx-1 expression was noted by the positive effect of phorbol 12-myristate …
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 …
Relationship Of Molecular Structure To The Mechanism Of Lysophospholipid-Induced Smooth Muscle Cell Proliferation, Yuh-Cherng Chai, David Binion, Guy Chisholm
Relationship Of Molecular Structure To The Mechanism Of Lysophospholipid-Induced Smooth Muscle Cell Proliferation, Yuh-Cherng Chai, David Binion, Guy Chisholm
Yuh-Cherng Chai
No abstract provided.
Regulation Of Cell Growth By Oxidized Ldl., Guy Chisolm, Yuh-Cherng Chai
Regulation Of Cell Growth By Oxidized Ldl., Guy Chisolm, Yuh-Cherng Chai
Yuh-Cherng Chai
The first reports of the influences of oxidized LDL (oxLDL) on cell function pertained to negative effects on cell growth—growth arrest, injury, and toxicity. Since these studies, it has become apparent that sublethal levels of oxLDL cause some, but not all, cells to proliferate. This review highlights the growth-promoting effects of oxLDL rather than its inhibitory or injurious effects. Smooth muscle cells (SMCs) and monocyte-macrophages proliferate after exposure to oxLDL; endothelial cells do not. Scavenger receptors are involved in the proliferative effects on monocyte-macrophages, whereas the effects of oxLDL on SMCs appear to be receptor independent. Lysophosphatidylcholine (lysoPC), and structurally …
Specificity And Cellular Mechanism Of Lysophosphatidylcholine Stimulation Of Vascular Smooth Muscle Cell Growth., Yuh-Cherng Chai, David Binion, Guy Chisolm
Specificity And Cellular Mechanism Of Lysophosphatidylcholine Stimulation Of Vascular Smooth Muscle Cell Growth., Yuh-Cherng Chai, David Binion, Guy Chisolm
Yuh-Cherng Chai
No abstract provided.
Oxidized Low Density Lipoprotein And Lysophosphatidylcholine Stimulate Cell Cycle Entry In Vascular Smooth Muscle Cells - Evidence For Release Of Fibroblast Growth Factor-2., Yuh-Cherng Chai, Philip Howe, Paul Dicorletto, Guy Chisolm
Oxidized Low Density Lipoprotein And Lysophosphatidylcholine Stimulate Cell Cycle Entry In Vascular Smooth Muscle Cells - Evidence For Release Of Fibroblast Growth Factor-2., Yuh-Cherng Chai, Philip Howe, Paul Dicorletto, Guy Chisolm
Yuh-Cherng Chai
We have previously shown that oxidized low density lipoprotein (LDL) but not native LDL stimulated DNA synthesis in cultured smooth muscle cells (SMC) and that α-tocopherol (vitamin E) inhibited this proliferative response (Lafont, A., Chai, Y. C., Cornhill, J. F., Whitlow, P. L., Howe, P. H., and Chisolm, G. M. (1995) J. Clin. Invest. 95, 1018-1025). The moiety of oxidized LDL that stimulates DNA synthesis and the cellular mechanism for this potentially mitogenic effect are not known. We now report that lipid fractions containing lysophospholipids from oxidized LDL or phospholipase A2-treated native LDL stimulated SMC DNA synthesis as did palmitoyl …
Protein S-Thiolation In Hepatocytes Stimulated By T-Butyl Hydroperoxide, Menadione, And Neutrophils, Yuh-Cherng Chai, S. Hendrich, James Thomas
Protein S-Thiolation In Hepatocytes Stimulated By T-Butyl Hydroperoxide, Menadione, And Neutrophils, Yuh-Cherng Chai, S. Hendrich, James Thomas
Yuh-Cherng Chai
In order to examine potentially important S-thiolated proteins, ^3^5S-labeled hepatocytes were exposed to oxidative stress. A similar group of S-thiolated proteins including carbonic anhydrase III was observed in cells treated with t-butyl hydroperoxide, menadione, or stimulated neutrophils. The radioactive thiols bound to hepatocyte proteins were identified by HPLC and more than 85% was glutathione. In menadione-treated hepatocytes, proteins were gradually S-thiolated over 30 min and 25% of the cellular glutathione pool became protein-bound. In t-butyl hydroperoxide-treated cells, S-thiolation was more transient and 11% of the glutathione was protein-bound. Neutrophil-treated hepatocytes had nearly the same amount of protein S-thiolation (8% after …
S-Thiolation Of Individual Human Neutrophil Proteins Including Actin By Stimulation Of The Respiratory Burst: Evidence Against A Role For Glutathione Disulfide, Yuh-Cherng Chai, S. Ashraf, R. Johnson, James Thomas
S-Thiolation Of Individual Human Neutrophil Proteins Including Actin By Stimulation Of The Respiratory Burst: Evidence Against A Role For Glutathione Disulfide, Yuh-Cherng Chai, S. Ashraf, R. Johnson, James Thomas
Yuh-Cherng Chai
Protein S-thiolation, a reversible modification of protein sulfhydryls resulting in formation of mixed-disulfides, was studied in human neutrophils stimulated with phorbol diester to produce superoxide anion. Rapid S-thiolation of several proteins was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Glutathione was identified as the primary protein-bound thiol by HPLC chromatography, contributing considerably more than 85% of the total. Minor amounts of homocysteine and/or cysteine were also detected as protein-bound thiols. During the first 30 min after stimulation, 10% of the cellular glutathione became protein bound (2 nmol/mg of protein). There was no increase in glutathione disulfide suggesting that S-thiolation of …
Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung
Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung
Yuh-Cherng Chai
No abstract provided.
S-Thiolation And Irreversible Oxidation Of Sulfhydryls On Carbonic Anhydrase Iii During Oxidative Stress: A Method For Studying Protein Modification In Intact Cells And Tissues, C. Lii, Yuh-Cherng Chai, W. Zhao, James Thomas, S. Hendrich
S-Thiolation And Irreversible Oxidation Of Sulfhydryls On Carbonic Anhydrase Iii During Oxidative Stress: A Method For Studying Protein Modification In Intact Cells And Tissues, C. Lii, Yuh-Cherng Chai, W. Zhao, James Thomas, S. Hendrich
Yuh-Cherng Chai
No abstract provided.