O'Shaughnessy J, Deseau V, Amini S, Rosen N, Bolen J B
Laboratory of Tumor Virus Biology and Medicine Branch, National Cancer Institute, Bethesda, Maryland 20892.
Oncogene Res. 1987;2(1):1-18.
We have compared in different human neuroblastoma cell lines and human glioblastoma cells the expression level, structure, and tyrosine-specific protein kinase activity of pp60c-src. Our results show that not all human neuroblastoma cell lines express pp60c-src molecules with amino-terminal structural alterations. In neuroblastoma cells which possess pp60c-src with altered gel migration, the diminished polyacrylamide gel mobility of pp60c-src was found not to be dependent upon amino-terminal phosphorylations since extensive treatment of these molecules with phosphatase did not significantly change their gel migration properties. Similar differences in gel migration were observed when RNA from the various neuroblastoma and glioblastoma cells was translated in vitro using either rabbit reticulocyte or wheat germ lysates. White the level of c-src mRNA in the different cells analyzed was found to be similar, the abundance of pp60c-src in these same cells was found to vary by as much as 12-fold. This suggests that the abundance of pp60c-src in human neuroendocrine tumors is regulated through post-transcriptional and/or post-translational events which may be related to the stage of neuronal differentiation of the cells. Based upon determination of pp60c-src abundance by immunoblot analysis, we demonstrate that pp60c-src molecules derived from human neuroblastoma and glioblastoma cells have very similar in vitro protein kinase activities.
我们已在不同的人类神经母细胞瘤细胞系和人类胶质母细胞瘤细胞中比较了pp60c-src的表达水平、结构及酪氨酸特异性蛋白激酶活性。我们的结果显示，并非所有人类神经母细胞瘤细胞系都表达具有氨基末端结构改变的pp60c-src分子。在具有迁移率改变的pp60c-src的神经母细胞瘤细胞中，发现pp60c-src在聚丙烯酰胺凝胶中迁移率降低并非依赖于氨基末端的磷酸化，因为用磷酸酶对这些分子进行广泛处理并未显著改变其凝胶迁移特性。当使用兔网织红细胞或麦胚裂解物在体外翻译来自各种神经母细胞瘤和胶质母细胞瘤细胞的RNA时，观察到了类似的凝胶迁移差异。虽然在所分析的不同细胞中c-src mRNA的水平相似，但在这些相同细胞中pp60c-src的丰度差异高达12倍。这表明人类神经内分泌肿瘤中pp60c-src的丰度是通过转录后和/或翻译后事件调节的，这些事件可能与细胞的神经元分化阶段有关。基于通过免疫印迹分析对pp60c-src丰度的测定，我们证明源自人类神经母细胞瘤和胶质母细胞瘤细胞的pp60c-src分子具有非常相似的体外蛋白激酶活性。
