STRUCTURE-FUNCTION RELATIONSHIPS OF THE IGE RECEPTOR

本书将继续系统地分析三个方面的内容： 免疫球蛋白E（IgE）受体的空间结构 复合物，它与其他细胞成分的相互作用，以及 它通过等离子体传输信号的机制 肥大细胞和嗜碱性粒细胞的膜触发脱粒， 过敏反应 结构图将通过以下方式进行扩展： 共振能量转移的测量 受体结合IgE和胞质暴露部分上的位点 这些受体被单克隆抗体标记。 IgE与受体相互作用的关键区域 将通过对多肽的遗传操作来检查 店 遗传学方法也将用于引入特定的 用于荧光标记的半胱氨酸残基， 可以进行传递测量以测试模型，该模型 IgE在结合时经历构象变化。 除了 提供IgE受体的基本信息和知识 相互作用在变态反应的临床治疗中可能是有价值的。 受体和其他细胞成分之间的相互作用 在IgE受体复合物聚集在一个 触发配置将通过荧光研究 光漂白恢复和电扩散测量 荧光标记单克隆抗体的横向迁移率 二聚化受体或特异于 部分特征化的元件，似乎与 受体。 一种测量旋转迁移率的方法， 将产生稳态磷光各向异性 受体相互作用的时间依赖性变化可能是 在发生单元触发的条件下监测。 的 与聚集的受体相互作用的特定成分 将使用微分化学 交联、放射性标记和纯化方案。 的 受体的胞质暴露部分的参与 在信号传导过程中与其它细胞成分相互作用 转导将通过测试的能力， 具有蛋白水解的胞质部分的IgE-受体复合物 在重组成完整细胞后， 细胞质特异性单克隆抗体 部分。 这些研究应有助于新的见解， 了解抗原桥接之间的事件链， 细胞表面的IgE-受体复合物和脱粒 信号了

The work proposed continues the systematic analysis of the three- dimensional structure of the immunoglobulin E (IgE) -receptor complex, its interactions with other cellular components, and the mechanism by which it transmits a signal across the plasma membrane of mast cells and basophils to trigger degranulation in allergic responses. The structural map will be extended by measurements of resonance energy transfer between well defined sites on receptor-bound IgE and cytoplasmically exposed portions of the receptor that are labeled by monoclonal antibodies. Regions of IgE that are critical for its interaction with receptor will be examined by genetic manipulation of the polypeptide chains. Genetic methods will also be used to introduce specific cysteine residues for fluorescent labeling such that energy transfer measurements may be carried out to test the model that IgE undergoes a conformation change upon binding. In addition to providing basic information knowledge of the IgE-receptor interaction may be valuable in clinical treatments of allergies. The interactions between receptors and other cellular components that occur after lgE-receptor complexes have clustered in a triggering configuration will be investigated by fluorescence photobleaching recovery and electrodiffusion measurements of the lateral mobility of fluorescently labeled monoclonal antibodies that dimerize the receptors or are specific for a partially characterized component that appears to associate with receptors. A procedure for measuring rotational mobility by steady-state phosphorescence anisotropy will be developed such that time-dependent changes in the receptor interactions may be monitored under conditions where cell triggering occurs. The particular components that interact with the clustered receptors will be characterized with the use of differential chemical crosslinking, radioactive labeling and purification schemes. The participation of the cytoplasmically exposed parts of the receptor in interactions with other cellular components during signal transduction will be investigated by testing the competence of lgE-receptor complexes with proteolyzed cytoplasmic portions after reconstitution into intact cells and also by microinjection into cells of the monoclonal antibodies specific for cytoplasmic portions. These studies should contribute new insights to understanding the chain-of-events between antigen bridging of lgE-receptor complexes on the cell surface and the degranulation signal.