EGF RECEPTOR FUNCTION AND CONTROL BY PHOSPHORYLATION

详细分析了涉及到的生化机制 细胞的生长和分化对我们理解 围绕正常生长和生长的分子事件 发展，以及那些潜在的致癌因素。这个 表皮生长因子(EGF)受体是一种EGF反应受体 蛋白质酪氨酸激酶经历快速配体诱导的自身 三个酪氨酸残基(酪氨酸1173、1148、1068)的磷酸化 位于分子的极端羧基末端区域。 EGF受体与某些 逆转录病毒转化蛋白(也可自我磷酸化 酪氨酸激酶，如erb B和src)及其在 各种人类肿瘤表明，它在细胞中起着关键作用 增殖和转化。这项提议旨在 通过磷酸化检测EGF受体的调节，用一种 强调自我磷酸化。具体地说，预计 拟议的研究计划将阐明以下内容：1) 自身磷酸化的生化特性及其调控 表皮生长因子受体蛋白-酪氨酸激酶及其配体结合 2)配体诱导的EGF受体自身的作用 包括细胞内在内的生物事件的磷酸化 酪氨酸磷酸化、DNA合成、钙摄取与细胞 部门，以及3)识别和表征其他 酪氨酸和丝氨酸/苏氨酸的EGF受体位点 磷酸化及其对受体影响的初步分析 功能。这项工作将使用两种正常的人类EGF受体 和可用的定点突变受体，其中特异性 酪氨酸自身磷酸化的位点已被改变为 苯丙氨酸残基(即单独的酪氨酸1173，酪氨酸1173加1068， Tyr 1173、1068和1148，以及一个突变体，其中这些酪氨酸 残基已完全删除)。这些研究涉及 蛋白质动力学分析方法的应用与发展 分离和结构鉴定、细胞培养和 细胞过程的荷尔蒙控制。所获得的知识 从这些研究中预计将更严格地建立 自身磷酸化调控表皮生长因子的机制 受体的功能，也应该证明对理解有价值 其他激素可能的调控机制 受自身磷酸化调控的受体/酶 它们在正常和异常细胞中都是重要的 新陈代谢和发育。

A detailed analysis of the biochemical mechanisms involved in cellular growth and differentiation is crucial to our understanding of the molecular events surrounding normal growth and development, as well as those underlying carcinogenesis. The epidermal growth factor (EGF) receptor is an EGF-responsive protein-tyrosine kinase that undergoes rapid ligand-induced self- phosphorylation on three tyrosine residues (Tyrs 1173, 1148, 1068) located in the extreme carboxy-terminal region of the molecule. The EGF receptor exhibits extensive homology with certain retroviral transforming proteins (also self-phosphorylating tyrosine kinases, e.g. erb B and src) and its overexpression in various human tumors suggests that it plays a critical role in cell proliferation and transformation. This proposal is designed to examine EGF receptor regulation by phosphorylation, with an emphasis on self-phosphorylation. Specifically, it is anticipated that the proposed research plan will elucidate the following: 1) The biochemical properties and regulation by self-phosphorylation of EGF receptor protein-tyrosine kinase and ligand binding activities, 2) the effect of ligand-induced EGF receptor self- phosphorylation on biological events including intracellular tyrosine phosphorylation, DNA synthesis, Ca++ uptake and cell division, and 3) identification and characterization of additional EGF receptor sites of tyrosine and serine/threonine phosphorylation and an initial analysis of their effect on receptor function. This work will use both normal human EGF receptors and available site-directed mutant receptors wherein specific sites of tyrosine self-phosphorylation have been altered to phenylalanine residues (i.e. Tyr 1173 alone, Tyrs 1173 plus 1068, Tyrs 1173, 1068 and 1148, and a mutant wherein these tyrosine residues have been deleted entirely). These studies involve the use and development of methods for kinetic analyses, protein isolation and structural characterization, cell culture and the hormonal control of cellular processes. The knowledge gained from these studies is expected to more rigorously establish the mechanisms by which self-phosphorylation can modulate EGF receptor function and should also prove valuable in understanding possible control mechanisms for other hormone receptors/enzymes that appear regulated by self-phosphorylation and which are important in normal and abnormal cellular metabolism and development.