The chymotrypsin inhibitor carbobenzyloxy-leucine-tyrosine-chloromethylketone interferes with phospholipase D activation induced by formyl-methionyl-leucyl-phenylalanine in human neutrophils.
The effects of carbobenzyloxy-leucine-tyrosine-chloromethylketone (zLYCK), an inhibitor of chymotrypsin-like proteases, on signal transduction in human neutrophils triggered by the chemoattractant formyl-methionyl-leucyl-phenylalanine (fMLP) were investigated. zLYCK (10 microM) inhibited the fMLP-induced respiratory burst in neutrophils treated with cytochalasin B. In the presence of zLYCK (10 microM), the activation of phospholipase D in response to fMLP addition was inhibited. zLYCK did not inhibit the binding of [3H] fMLP to its receptor or the enzymic activity of phospholipase D because the response to ionomycin was unaffected. The effect of zLYCK on phospholipase D correlated well with its effects on the accumulation of diglycerides, which was also inhibited in the presence of zLYCK. In electropermeabilized neutrophils, too, zLYCK caused an inhibition of the fMLP-induced respiratory burst and the fMLP-induced activation of phospholipase D. Interestingly, this inhibition could be bypassed by guanosine 5'-O-(thiotriphosphate). We conclude that the inhibition of the respiratory burst in human neutrophils by zLYCK is caused by the selective inhibition of signal transduction leading to activation of phospholipase D and that zLYCK might be a useful probe to study the role of phospholipase D in neutrophil activation.
Kessels
G C
GC
Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, Amsterdam.
Gervaix
A
A
Lew
P D
PD
Verhoeven
A J
AJ
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D020404:Glycerophospholipids; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010100:Oxygen / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis; D010739:Phospholipase D / Q000378:metabolism*; D015398:Signal Transduction
D000590:Amino Acid Chloromethyl Ketones; D004075:Diglycerides; D020404:Glycerophospholipids; D010712:Phosphatidic Acids; C051521:phosphatidylethanol; C070517:carbobenzyloxyleucyl-tyrosine chloromethyl ketone; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010739:Phospholipase D; D002918:Chymotrypsin; D010100:Oxygen