Selective potentiation of c-fps/fes transforming activity by a phosphatase inhibitor.
Selective potentiation of c-fps/fes transforming activity by a phosphatase inhibitor.
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磷酸酶抑制剂选择性增强 c-fps/fes 转化活性。
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
W. Vass
中科院分区：
文献类型：
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作者：
R. Feldman;D. Lowy;W. Vass
当人 c-fps/fes 在 NIH 3T3 细胞中以足够高的水平表达时，可以诱导细胞转化。为了探究 c-fps/fes 产品 NCP92 的作用机制，我们研究了在过度表达 NCP92 的细胞中稳定磷酸酪氨酸的生物学和生化后果。在这项研究中，我们报告说，当表达 c-fps/fes 的细胞与低浓度的钒酸钠（一种酪氨酸磷酸酶抑制剂）一起孵育时，c-fps/fes 的转化活性可增强近两个数量级。这种效应与 NCP92 及其主要细胞底物中磷酸酪氨酸水平增加三倍相关。与 c-src 不同，NCP92 具有单个酪氨酸磷酸化位点，钒酸盐处理可诱导其在体内磷酸化。人们发现这对 NCP92 激酶比活性有积极影响，但在使用低浓度的钒酸盐时，这种影响非常小。结果与以下假设一致：增强作用是 NCP92 转化关键靶标中磷酸酪氨酸稳定化的结果，而不是钒酸盐对 NCP92 激酶的直接作用。钒酸盐对 c-fps/fes 的增强作用相对特异；该试剂不会影响 gag-v-fps/fes 的高转化活性，也不会增强活性较低的 c-ras、c-src 或 EGF 受体基因，尽管后两个基因编码酪氨酸激酶。 c-fps/fes 对磷酸酪氨酸稳定化的生物反应的特异性表明该分子具有独特的调节模式和作用机制。
Human c-fps/fes when expressed at sufficiently high levels in NIH 3T3 cells can induce cellular transformation. To probe the mechanism of action of the c-fps/fes product NCP92, we have examined the biological and biochemical consequences of stabilizing phosphotyrosine in cells that overexpress NCP92. In this study we report that when cells expressing c-fps/fes are incubated with low concentrations of sodium vanadate, a tyrosine phosphatase inhibitor, the transforming activity of c-fps/fes can be potentiated by nearly two orders of magnitude. This effect was associated with a threefold increase in the level of phosphotyrosine in NCP92 and its major cellular substrates. Unlike c-src, NCP92 had a single tyrosine phosphorylation site, and vanadate treatment induced its phosphorylation in vivo. This was found to have a positive effect on NCP92 kinase specific activity, but at the low concentrations of vanadate that were used, this effect was very small. The results are consistent with the hypothesis that potentiation was a consequence of the stabilization of phosphotyrosine in critical targets of transformation of NCP92, rather than from a direct effect of vanadate on NCP92 kinase. The potentiating effect of vanadate was relatively specific for c-fps/fes; this reagent did not affect the high transforming activity of gag-v-fps/fes, nor did it enhance the less active c-ras, c-src, or EGF receptor genes, although the latter two genes encode tyrosine kinases. The specificity of the biological response of c-fps/fes to the stabilization of phosphotyrosine suggests that this molecule has a distinct mode of regulation and mechanism of action.