Tyrosine phosphorylation of C-Cbl facilitates adhesion and spreading while suppressing anchorage-independent growth of V-Abl-transformed NIH3T3 fibroblasts
Tyrosine phosphorylation of C-Cbl facilitates adhesion and spreading while suppressing anchorage-independent growth of V-Abl-transformed NIH3T3 fibroblasts
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DOI：
10.1038/sj.onc.1202672
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发表时间：
1999-06-24
期刊：
影响因子：
8
通讯作者：
Tsygankov, AY
中科院分区：
文献类型：
--
作者：
Feshchenko, EA;Shore, SK;Tsygankov, AY
原癌蛋白c-Cbl在正常细胞中响应于各种外部刺激而变得酪氨酸磷酸化，以及在由致癌蛋白酪氨酸激酶转化的细胞中。c-Cbl的酪氨酸磷酸化上调其与多种关键信号分子的结合。然而，c-Cbl介导的信号传导的生物学后果还不充分理解。为了分析c-Cbl的生物学功能，我们在v-Abl转化的NIH 3 T3成纤维细胞中过表达野生型c-Cbl及其酪氨酸磷酸化缺陷突变体形式。在这个系统中，野生型c-Cbl促进粘附和传播的v-Abl转化的成纤维细胞的细胞外基质，同时减少这些细胞的锚定独立性，测量其在软琼脂中的集落形成效率。因此，野生型c-Cbl的过表达表现出总体的转化抑制作用。相比之下，c-Cbl的酪氨酸磷酸化缺陷形式的过表达既不增加粘附也不增加v-Abl转化的成纤维细胞的锚定依赖性。对c-Cbl的单个酪氨酸磷酸化位点在这些现象中的作用的分析表明，磷脂酰肌醇-3 '激酶和CrkL衔接蛋白可能参与了所观察到的c-Cbl的作用。总之，本报告中的结果表明，c-Cbl参与调节细胞粘附和细胞骨架重排，这些影响c-Cbl依赖于其酪氨酸磷酸化。
The protooncogenic protein c-Cbl becomes tyrosine phosphorylated in normal cells in response to a variety of external stimuli, as well as in cells transformed by oncogenic protein tyrosine kinases. Tyrosine phosphorylation of c-Cbl upregulates its binding to multiple crucial signaling molecules. However, the biological consequences of c-Cbl-mediated signaling are insufficiently understood. To analyse the biological functions of c-Cbl, we overexpressed wild-type c-Cbl and its tyrosine phosphorylation-defective mutant form in v-Abl-transformed NIH3T3 fibroblasts. In this system, wild-type c-Cbl facilitated adhesion and spreading of v-Abl-transformed fibroblasts on the extracellular matrix, while reducing anchorage independence of these cells, as measured by their colony-forming efficiency in soft agar. Therefore, overexpression of wild-type c-Cbl exhibits an overall transformation-suppressing effect. By contrast, overexpression of a tyrosine phosphorylation-defective form of c-Cbl increases neither adhesion nor anchorage dependence of v-Abl-transformed fibroblasts. Analysis of the role of individual tyrosine phosphorylation sites of c-Cbl in these phenomena indicates that both phosphatidylinositol-3' kinase and the CrkL adaptor protein may be involved in the observed effects of c-Cbl. To summarize, the results presented in this report indicate that c-Cbl is involved in regulation of cell adhesion and cytoskeletal rearrangements, and that these effects of c-Cbl are dependent on its tyrosine phosphorylation.