Redox regulation of signal transduction in vascular smooth muscle cells: thiol oxidizing agents induced phospholipase D.
Decrease in intracellular thiols leads to oxidative stress and thus may cause alterations in the activity of redox-sensitive enzymes required for signal transduction. Here, we report that, N-ethylmaleimide and phenylarsine oxide, which are known to oxidize free thiols as well as protein thiols, induced phosphatidyl ethanol generation in the micromolar range suggesting activation of phospholipase D in vascular smooth muscle cells. These agents also induced significant phosphatidic acid and diacylglycerol generation without causing protein kinase C activation. Phenylarsine oxide and N-ethyl maleimide induced phospholipase D activation is protein kinase C independent as it was not inhibited by compound-3 and bisindolylmaleimide, potent protein kinase C inhibitors. Tyrosine kinase inhibitor herbimycin A by itself activated PLD, but inhibited the phospholipase D activation by phenylarsine oxide and N-ethylmaleimide. These results suggest that oxidation of the cellular thiols activates phospholipase D independent of protein kinase C.
Taher
M M
MM
Department of Surgery, Medical College of Virginia, VCU, Richmond 23298, USA. mtaher@hsc.vcu.edu
Mahgoub
M A
MA
Abd-Elfattah
A S
AS
D000818:Animals; D001152:Arsenicals / Q000494:pharmacology*; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D001152:Arsenicals; D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; C029341:oxophenylarsine; D019000:Phosphotyrosine; D011493:Protein Kinase C; D010739:Phospholipase D; C088060:bisindolylmaleimide; D005033:Ethylmaleimide