Inhibition of platelet phospholipid methylation during platelet secretion.

摘要: A pathway for the synthesis of membrane phosphatidylcholine involving N-methylation phosphatidylethanolamine has been detected in several types mammalian cells. Furthermore, it implicated coupling agonist binding to cell response. We examined whether human platelets exhibit this synthetic and platelet agonists influence its activity. When washed were incubated with 0.15 microM L-[methyl-3H]methionine at 37 degrees C, they incorporated methyl-3H into their phospholipids linearly rate 1 pmole/10(9) platelets/hr. 20 radiolabeled methionine, about 15 The radioactivity was found predominantly phosphatidyl- N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine, phosphatidylcholine. Thrombin caused an immediate (within sec) sustained (up 30 min) decrease extent N- methylation phospholipids. This accounted by a methylated rather than increase degradation. thrombin effect correlated serotonin release could be dissociated from aggregation prostaglandin synthesis. also decreased when choline used as substrate. Other such epinephrine, adenosine diphosphate (ADP), or A23187 phospholipid under conditions which stimulated release. These data demonstrate that are capable synthesizing perturb induce secretion. precise role either resting remains established.