TRANSFORMATION SPECIFIC SIGNALING MEDIATED BY VERBS

描述：禽成红细胞增多症病毒的v-erbB癌基因 编码具有酪氨酸激酶活性的截短生长因子受体。 这种病毒癌基因的表达导致纤维肉瘤、红白血病和 血管瘤 了解信号转导的机制， v-ErbB癌蛋白将为酪氨酸激酶信号传导提供新见解 转导途径，转化为形成特异性 多蛋白复合物，并具有很大的潜力，提供深入了解 人类恶性肿瘤的分子生物学 随着这些长期目标的实现， 记住，本提案中概述的实验将使用特征良好的， 切割酪氨酸的v-ErbB的转化特异性结构突变体 转化成纤维细胞中的激酶信号通路。 这种方法有 已经揭示了转化特异性多蛋白的形成 v-ErbB转化的成纤维细胞中的信号传导复合物。 该复合物 由两个信号衔接分子（SHC和GRB 2），一个鸟嘌呤 核苷酸交换因子（SOS），其是一种酪氨酸磷酸化形式， 细胞骨架调节蛋白caldesmon和一种新的酪氨酸 磷酸化蛋白（pp 75）。 要检验的假设是， 由v-ErbB启动的致癌信号通过 SHC-GRB 2-SOS-钙调蛋白-pp 75复合物，以及酪氨酸磷酸化 caldesmon和pp 75参与非锚定性的调节 生长和致瘤性。 本研究的具体目的是（一） 确定钙调素与多蛋白的结合机制 复合物，（ii）定义caldesmon在v-ErbB介导的功能作用 转化，和（iii）表征新的75 kd酪氨酸 磷酸化的蛋白质。

DESCRIPTION: The v-erbB oncogene of the avian erythroblastosis virus encodes a truncated growth factor receptor with tyrosine kinase activity. Expression of this viral oncogene causes fibrosarcomas, erythroleukemias and hemangiosarcomas. Understanding the mechanisms of signal transduction by the v-ErbB oncoprotein will offer insights into tyrosine kinase signal transduction pathways, into the formation of transformation-specific multiprotein complexes, and has great potential to offer insights into the molecular biology of human malignancies. With these long-term goals in mind, the experiments outlined in this proposal will use well-characterized, transformation-specific, structural mutants of v-ErbB to dissect tyrosine kinase signaling pathways in transformed fibroblasts. This approach has already revealed the formation of a transformation-specific multiprotein signaling complex in v-ErbB transformed fibroblasts. This complex is composed of two signal adapter molecules (SHC and GRB2), a guanine nucleotide exchange factor (SOS), a tyrosine phosphorylated form of the cytoskeletal regulatory protein caldesmon, and a novel tyrosine phosphorylated protein (pp75). The hypothesis to be tested is that the oncogenic signals initiated by v-ErbB are transduced through the SHC-GRB2-SOS-caldesmon-pp75 complex, and that tyrosine phosphorylated caldesmon and pp75 participate in the regulation of anchorage-independent growth and tumorigenicity. The specific aims of this study are to (I) determine the mechanism of association of caldesmon with the multiprotein complex, (ii) define the functional role of caldesmon in v-ErbB mediated transformation, and (iii) characterize the novel 75 kd tyrosine phosphorylated protein in this signaling complex.