Ochi H, Kume N, Nishi E, Moriwaki H, Masuda M, Fujiwara K, Kita T
Department of Geriatric Medicine, Graduate School of Medicine, Kyoto University, Japan.
Biochem Biophys Res Commun. 1998 Feb 24;243(3):862-8. doi: 10.1006/bbrc.1998.8198.
Lysophosphatidylcholine (lyso-PC), a biologically active phospholipid, appears to modulate various endothelial cell functions through tyrosine kinase-dependent signaling pathways. In cultured bovine aortic endothelial cells (BAEC), we have found that a 130 kDa protein (p130) was rapidly tyrosine phosphorylated within 2 min and sustained for, at least, 1 hr in response to 10 mumol/L of lyso-PC but not to phorbol myristate acetate (PMA). Prolonged preexposure to PMA did not affect lyso-PC-induced p130 tyrosine phosphorylation, suggesting that mechanisms independent of protein kinase C may be involved. Fractionation of the cell lysates revealed that p130 was detectable in the membrane fraction but not in the cytosolic fraction. Immunoprecipitation followed by immunoblotting of lyso-PC-treated BAEC identified p130 as bovine PECAM-1. Tyrosine phosphorylation of PECAM-1 appears to be one of the earliest events elicited by lyso-PC, and may play a role in lyso-PC-induced modulation of endothelial functions.
溶血磷脂酰胆碱（lyso-PC）是一种生物活性磷脂，似乎通过酪氨酸激酶依赖性信号通路调节各种内皮细胞功能。在培养的牛主动脉内皮细胞（BAEC）中，我们发现一种130 kDa的蛋白质（p130）在响应10 μmol/L的lyso-PC时，在2分钟内迅速发生酪氨酸磷酸化，并至少持续1小时，而对佛波醇肉豆蔻酸酯（PMA）则无此反应。长时间预先暴露于PMA并不影响lyso-PC诱导的p130酪氨酸磷酸化，这表明可能涉及独立于蛋白激酶C的机制。细胞裂解物的分级分离显示，p130在膜组分中可检测到，而在胞质组分中未检测到。对lyso-PC处理的BAEC进行免疫沉淀后再进行免疫印迹分析，确定p130为牛PECAM-1。PECAM-1的酪氨酸磷酸化似乎是lyso-PC引发的最早事件之一，可能在lyso-PC诱导的内皮功能调节中起作用。
