ISOLATION AND CHARACTERIZATION OF THE EGF RECEPTOR PUTATIVE SUBSTRATE (EPS10).

表皮生长因子(EGF)与其受体结合激活 受体的酪氨酸激酶活性，然后将自身磷酸化并 其他胞内蛋白质。这些蛋白质统称为EGF。 受体酪氨酸激酶底物。一种分离这些酶的方法 底物已经被开发出来。这种方法涉及到分离出 抗磷酸酪氨酸抗体制备的含磷酸酪氨酸蛋白 从经EGF处理的细胞中提取。这些免疫纯化的蛋白质随后被 用于免疫兔以制备特异性抗血清。 这些蛋白质。这些抗血清随后被用来筛选 编码EGF的潜在cDNA克隆的表达cDNA文库 受体激酶底物。 在分离的c DNA克隆中，命名为EPS(EPS) 受体假定底物)，eps10的全长cDNA克隆 编码583个氨基酸的蛋白质。Eps10 Has基因的序列分析 据透露，它与之前确认的Radixin完全相同 与Ezrin高度相似的细胞骨架蛋白 和Mosein，这是4.1带蛋白家族的两个成员。这三个人 相关蛋白进一步用特异性抗体和 研究表明，Ezrin是EGF和血小板衍生的底物。 生长因子(PDGF)受体。RADX是PDGF受体的特异性受体 而Moesin不会被这两种受体磷酸化。它也是 证明了之前描述的一种肿瘤移植抗原 甲基胆蒽诱导的肉瘤中的一种是Ezrin。

Binding of epidermal growth factor (EGF) to its receptor activates the receptor's tyrosine kinase activity which then phosphorylates itself and other intracellular proteins. These proteins are collectively termed EGF receptor tyrosine kinase substrates. A method to isolate these kinase substrates has been developed. This method involved the isolation of phosphotyrosine-containing proteins by anti-phosphotyrosine antibodies from cells treated with EGF. These immunopurified proteins were then used to immunize rabbits for the production of antisera specific for these proteins. These antisera were subsequently used to screen expression cDNA libraries for potential cDNA clones encoding the EGF receptor kinase substrates. Among the isolated cDNA clones, which are designated eps (epidermal receptor putative substrate), the full-length cDNA clone for eps10 encodes a protein of 583 amino acids. Sequence analysis of eps10 has revealed that it is identical to radixin, a previously identified cytoskeletal protein which shares a high degree of similarity with ezrin and mosein, two members of the band 4.1 family of proteins. These three related proteins were further characterized using specific antibodies and it was shown that ezrin is a substrate for both EGF and platelet-derived growth factor (PDGF) receptor. Radixin is specific for the PDGF receptor and moesin is not phosphorylated by these two receptors. It was also demonstrated that a previously described tumor transplantation antigen of the methylcholanthrene-induced sarcoma is ezrin.