NERVE GROWTH FACTOR RECEPTOR--A MOLECULAR ANALYSIS

神经生长因子(NGF)是重要的生长调节因子 促进细胞存活和分化的多肽 发育中的神经系统中未成熟的神经母细胞。不像 大多数刺激细胞复制的生长激素，NGF 抑制细胞增殖，诱导细胞成熟 携带特定的神经生长因子受体。因此，NGF-NGF受体 交互作为一种重要的模型系统在 研究调节细胞生长的正常机制 和差异化。此外，由于NGF的影响 甚至延伸到含有功能性受体的肿瘤细胞，NGF 作为一种生长抑制因子具有潜在的临床意义 起源于神经脊的肿瘤。 尽管NGF是第一个被发现的生长因子，但它的 作用机制还不是很清楚，除了它的 通过结合到高亲和力的细胞表面来启动动作 受体。这项建议旨在界定 NGF受体在启动细胞对NGF反应中的作用 最近克隆的编码人类神经生长因子受体的基因。 分子生物学和生物化学相结合的方法将是 用于确定功能活动高的结构 亲和力受体。具体地说，我们计划：(A)将 人神经生长因子受体克隆入神经源性细胞 CREST来确定细胞特征，这些特征是 负责对NGF的响应；(B)定义分子 受体高亲和力形式和低亲和力形式的基础 聚乙二醇膜融合实验；(C) 确定负责高亲和力的受体的结构域 配体结合、内化及其与细胞的相互作用 膜蛋白；(D)高密度脂蛋白的生化特征 应用亲和层析和(E)亲和受体复合体 使用基因转移来鉴定细胞中的其他基因产物 功能活性高亲和力所需的膜 受体。

Nerve growth factor (NGF) is an important growth regulatory polypeptide which promotes the survival and differentiation of immature neuroblasts in the developing nervous system. Unlike most growth hormones which stimulate cell replication, NGF inhibits cell proliferation and induces the maturation of cells bearing specific NGF receptors. Thus, the NGF-NGF receptor interaction serves as an important model system to use in investigating the normal mechanisms which regulate cell growth and differentiation. Furthermore, since the effects of NGF extend even to neoplastic cells bearing functional receptors, NGF is of potential clinical significance as a growth inhibitor of neoplasias of neural crest origin. Although NGF was the first growth factor to be identified, its mechanism of action is not well understood, except that its actions are initiated by binding to a high affinity cell surface receptor. This proposal is directed towards defining the role of the NGF receptor in initiating cellular responses to NGF, using the recently cloned gene that encodes the human NGF receptor. A combined molecular biological and biochemical approach will be used to determine the structure of the functionally active high affinity receptor. Specifically we plan to: (a) transfect the human NGF receptor clone into cells derived from the neural crest to determine the cellular characteristics which are responsible for responsiveness to NGF; (b) define the molecular basis of the high and low affinity forms of the receptor by membrane fusion experiments using PEG-mediated fusion; (c) define the domains of the receptor responsible for high affinity ligand binding, internalization and interactions with cell membrane proteins; (d) biochemically characterize the high affinity receptor complex using affinity chromatography and (e) use gene transfer to identify other gene products in the cell membrane which are required for functionally active high affinity receptor.