尾加压素增加血管平滑肌细胞粘着斑激酶的含量和活力

在体外培养的血管平滑肌细胞上,采用蛋白印迹杂交免疫沉淀的方法,研究尾加压素Ⅱ（ＵⅡ）与粘着斑激酶（ＦＡＫ）介导的信号传导之间的关系。结果表明,ＵⅡ在１０＾－８、１０＾－７和１０＾－６ｍｏｌ／Ｌ的深度时,可分别使ＦＡＫ活力增加２．２、３．０４和０．７３倍。加入ＵⅡ在（１０＾０７ｍｏｌ／Ｌ）５ｍｉｎ后,ＦＡＫ活力增加９５％,但与对照组相比无显著性差异（Ｐ〉０．０５０,刺激１０ｍｉｎ后,ＦＡＫ活力升高３

Content and activity of the focal adhesion kinase in cultured vascular smooth muscle cells enhanced by urotensin II

Urotensin II (U II) is the most potent vasoconstrictor identified in vivo, which plays an important role in the smooth muscle cell proliferation in atherosclerosis. All available information suggests that focal adhesion kinase (FAK) is at the crossroads of multiple signaling pathways and is essential for cell proliferation. But the effect of U II on the FAK mediated signal transduction pathway is unclear. In this study, FAK content and tyrosine phosphorylation were assessed by Western blot and immunoprecipitation in cultured rat vascular smooth muscle cells. Increased protein tyrosine phosphorylation was observed within 5 min of U II 10(-7) (mol/L) addition and was maximal by 30 min, while FAK protein content showed no change during the first 30 min but it increased at 2 h reaching a plateau by 4 h, and decreased after 6 h. In addition, the elevated phosphorylation of FAK was detected upon U II stimulation at 10(-8) mol/L, being maximal at 10(-7) mol/L, but decreased at 10(-6) mol/L. Treatment of the cells with cytochalasin B (50 micromol/L), which disrupted the organization of cytoskeleton, had no influence on the increased FAK tyrosine phosphorylation in response to U sti II mulation. In order to study the relationship between FAK and mitogen-activated protein kinase, calmodulin and protein kinase C, selective inhibitors PD98059 (50 micromol/L), W7 (50 micromol/L) and H7 (50 micromol/L) were added following U II treatment. Neither PD98059 nor W7 influenced the increased FAK tyrosine phosphorylation, but H7 further increased it. These findings indicate that FAK activation is independent of the integrity of cytoskeleton and closely related to protein kinase C, but had no relation with mitogen activated protein kinase and calmodulin.