Horak I D, Corcoran M L, Thompson P A, Wahl L M, Bolen J B
Laboratory of Tumor Virus Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
Oncogene. 1990 Apr;5(4):597-602.
Platelets possess high levels of tyrosine protein kinase activity which has been associated, in part, with the abundant expression of pp60c-src. We report here that in addition to pp60c-src at least one other member of the src family of tyrosine protein kinases, p60fyn, is expressed in platelets. The abundance of p60fyn was estimated to be approximately 20- to 40-fold higher in platelets than in human fibroblasts. In platelets the abundance of p60fyn was determined to be approximately 5- to 10-fold lower than the abundance of pp60c-src. Thrombin-mediated activation of human platelets was found to rapidly elevate the level of detectable phosphotyrosine containing proteins. However, thrombin treatment of platelets did not result in significant alterations in either the abundance or activity of pp60c-src or p60fyn. These observations demonstrate that at least two members of the src family of tyrosine protein kinases (pp60c-src and p60fyn) are expressed in human platelets, but leave unresolved the question of whether these protein kinases play a role in platelet signal transduction events.
血小板具有高水平的酪氨酸蛋白激酶活性，这在一定程度上与pp60c-src的大量表达有关。我们在此报告，除了pp60c-src之外，血小板中还表达了酪氨酸蛋白激酶src家族的至少另一个成员p60fyn。据估计，血小板中p60fyn的丰度比人成纤维细胞中的高约20至40倍。在血小板中，p60fyn的丰度被确定比pp60c-src的丰度低约5至10倍。发现凝血酶介导的人血小板激活会迅速提高可检测到的含磷酸酪氨酸蛋白的水平。然而，用凝血酶处理血小板并不会导致pp60c-src或p60fyn的丰度或活性发生显著变化。这些观察结果表明，酪氨酸蛋白激酶src家族的至少两个成员（pp60c-src和p60fyn）在人血小板中表达，但这些蛋白激酶是否在血小板信号转导事件中起作用的问题仍未解决。
