Inhibition of mink lung epithelial cell proliferation by transforming growth factor-beta is coupled through a pertussis-toxin-sensitive substrate.
Inhibition of mink lung epithelial cell proliferation by transforming growth factor-beta is coupled through a pertussis-toxin-sensitive substrate.
复制标题
通过转化生长因子-β 抑制水貂肺上皮细胞增殖是通过百日咳毒素敏感底物耦合的。
DOI：
10.1042/bj2660537
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Leof,EB
中科院分区：
文献类型：
--
作者：
Howe,PH;Cunningham,MR;Leof,EB
转化生长因子β1抑制血清和表皮生长因子对水貂肺上皮细胞(CCL64)的增殖反应。这种对转化生长因子β1的反应可以通过预先将细胞暴露在纳克浓度的百日咳毒素(PT)中来抑制，这表明鸟嘌呤核苷酸结合调节蛋白(G蛋白)参与了转化生长因子β1诱导的生长抑制。为了进一步确定这种G蛋白依赖性，我们通过化学诱变分离出了一个对转化生长因子β1具有抗性的CCL64变异体(CCL64-D1)。在亲代CCL64细胞中，转化生长因子β1既能刺激GTP[35S](鸟苷5‘-[35S]硫代]三磷酸)结合，又能刺激GTP酶活性，而在CCL64-D1变异体中，转化生长因子β1不起作用。用抗血清定量免疫印迹G蛋白α和β亚基，以及PT催化的ADP核糖化分析，显示CCL64-D1变异体与亲本细胞相比G蛋白表达水平没有明显变化。与另一个抗转化生长因子β的克隆MLE-M相比，CCL64-D1细胞保留了所有三种转化生长因子β细胞表面结合蛋白。在这些研究的基础上，我们认为，转化生长因子β1介导的CCL64上皮细胞生长抑制的一个必要成分是转化生长因子β1受体与G蛋白激活的偶联。
Transforming growth factor beta 1 (TGF beta 1) inhibits the proliferative response of mink lung epithelial cells (CCL64) to serum and to epidermal growth factor (EGF). This response to TGF beta 1 can be inhibited by prior exposure of the cells to nanogram concentrations of pertussis toxin (PT), suggesting the involvement of a guanine-nucleotide-binding regulatory protein (G-protein) in mediating TGF beta 1-induced growth inhibition. To characterize further this G-protein dependence, we have isolated, by chemical mutagenesis, a CCL64 variant (CCL64-D1) that is resistant to TGF beta 1. Whereas in the parental CCL64 cells TGF beta 1 stimulates both GTP[35S] (guanosine 5′-[gamma-[35S]thio]triphosphate) binding and GTPase activity, in the CCL64-D1 variants TGF beta 1 is without effect. Quantitative immunoblotting with antisera for G-protein alpha- and beta-subunits, as well as PT-catalysed ADP-ribosylation analyses, revealed no appreciable changes in the level of G-protein expression in the CCL64-D1 variants compared with parental cells. In contrast with another TGF beta-resistant clone, MLE-M, which we show lacks detectable type I receptor protein, the CCL64-D1 cells retain all three TGF beta cell-surface binding proteins. On the basis of these studies, we propose that a necessary component of TGF beta 1-mediated growth inhibition in CCL64 epithelial cells is the coupling of TGF beta 1 receptor binding to G-protein activation.