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Thrombin‐induced human platelet aggregation is inhibited by protein‐tyrosine kinase inhibitors, ST638 and genistein
Author(s) -
Asahi Momoyo,
Yanagi Shigeru,
Ohta Shinji,
Inazu Tetsuya,
Sakai Keiko,
Takeuchi Furnito,
Taniguchi Takanobu,
Yamamura Hirohei
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80728-y
Subject(s) - genistein , thrombin , chemistry , tyrosine kinase , phosphorylation , platelet , tyrosine phosphorylation , tyrosine , intracellular , biochemistry , signal transduction , biology , endocrinology , immunology
We have investigated the involvement of protein‐tyrosine kinases in thrombin‐induced aggregation of human platelets, using ST638 and genistein which are known inhibitors of protein‐tyrosine kinase. Preincubation of platelets with 50 μM of ST638 or 25 μg/ml of genistein completely blocked the platelet aggregation induced with 0.05 unit/ml of thrombin. The increase of protein‐tyrosine phosphorylation bands (135‐, 124‐, 76‐, 64‐, and 60‐kDa) induced with thrombin was also inhibited by these inhibitors in a dose‐dependent manner. These inhibitors also blocked the platelet aggregation and protein‐tyrosine phosphorylation induced with thrombin in aspirin‐treated platelets. Increase of the intracellular Ca 2+ concentration induced by thrombin was also inhibited by higher concentrations of genistein. The results suggest that the protein‐tyrosine phosphorylation plays a certain role in platelet activation having some relation to the intracellular Ca 2+ concentration.