Satoh T, Nakafuku M, Miyajima A, Kaziro Y
DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, CA 94304-1104.
Proc Natl Acad Sci U S A. 1991 Apr 15;88(8):3314-8. doi: 10.1073/pnas.88.8.3314.
The protooncogene ras acts as a component of signal-transduction networks in many kinds of cells. The ras gene product (p21) is a GTP-binding protein, and the activity of the protein is regulated by bound GDP/GTP. Recent studies have shown that a certain class of growth factors stimulates the formation of active p21-GTP complexes in fibroblasts and that oncogene products with enhanced tyrosine kinase activities have a similar effect on ras p21. We have measured the ratio of active GTP-bound p21 to total p21 in several lymphoid and myeloid cell lines in order to understand the role of ras in the proliferation of these cells. Interleukin 2 (IL-2), IL-3, and granulocyte/macrophage colony-stimulating factor (GM-CSF) enhance the formation of the active p21.GTP, whereas IL-4 has no effect on p21-bound GDP/GTP. These results strongly suggest that ras p21 acts as a transducer of signals from IL-2, IL-3, and GM-CSF, but not from IL-4.
原癌基因ras在多种细胞中作为信号转导网络的一个组成部分发挥作用。ras基因产物（p21）是一种GTP结合蛋白，该蛋白的活性受结合的GDP/GTP调节。最近的研究表明，某一类生长因子可刺激成纤维细胞中活性p21-GTP复合物的形成，并且具有增强酪氨酸激酶活性的癌基因产物对ras p21也有类似作用。为了了解ras在这些细胞增殖中的作用，我们测定了几种淋巴细胞和髓细胞系中活性GTP结合的p21与总p21的比例。白细胞介素2（IL-2）、IL-3和粒细胞/巨噬细胞集落刺激因子（GM-CSF）可增强活性p21.GTP的形成，而IL-4对结合p21的GDP/GTP没有影响。这些结果强烈表明，ras p21作为来自IL-2、IL-3和GM-CSF的信号转导分子，但不是来自IL-4的信号转导分子。
