TRANSMEMBRANE SIGNALING IN IMMUNOLOGICAL DEGRANULATION

分泌血管活性胺、SRSA、胰高血糖素和其他炎性物质 介质是一个过程，患者，临床医生，药物 化学家和基础科学家都会从理解中受益。 全身性过敏反应和急性炎症的其他表现是一种 抗原诱导的免疫球蛋白E（IgE）交联的直接结果 与肥大细胞和嗜碱性粒细胞表面的Fc受体结合。 的 由交联Fc受体产生的直接细胞质信息不 已知的;几个生化反应被设置在运动中，但究竟如何 它们被触发，以及它们以何种方式耦合到囊泡膜 聚变仍不确定。 许多证据表明，离子门控 质膜中的通道是抗原性的早期结果。 挑战;钙进入是一个重要的步骤，膜 甚至在没有钙流入的情况下也发生去极化。 然而，到目前为止， 通道激活的证据是间接的或有限的 时间分辨率 这个项目的目标是使用强大的技术gigaseal 膜片钳记录直接观察离子通道的运作 在脱粒肥大细胞和大鼠嗜碱性粒细胞的质膜中， 白血病细胞 未受刺激的细胞中存在的通道类型将首先被 确定并表征了离子选择性，电压依赖性， 开放时间、单位电导和药理学特征。 的贡献 然后评估这些通道对脱粒的影响。 具体 需要回答的问题是：1）交联的Fc Epidermal受体 离子通道，如果有，它的离子特异性是什么？ 2)桥接是否 产生细胞内第二信使， 其他蛋白质的门控通道活性 3)钙内流与 膜去极化，即，是相同的还是不同的通道 这两个事件？ 4)通道失活是造成这种现象的原因吗 脱敏？ 5)特异性通道阻滞剂能阻止胞吐作用吗 如果是这样，它们在什么情况下会干扰 脱粒 在一项相关的研究中，电场诱导的机制 将检测大鼠嗜碱性白血病细胞的5-羟色胺释放。 的 这项工作的长期目标是了解 免疫系统内的跨膜信号装置。

Secretion of vasoactive amines, SRSA, prostaglandins and other inflammatory mediators is a process which the patient, clinician, pharmaceutical chemist, and basic scientist would each profit from understanding. Systemic anaphylaxis and other manifestations of acute inflammation are a direct result of antigen-induced cross-linkage of immunoglobulin E (IgE) bound to Fc receptors on the surface of mast cells and basophils. The immediate cytoplasmic message created by cross-linked Fc receptors is not known; several biochemical reactions are set in motion, but exactly how they are triggered, and in what way they are coupled to vesicle-membrane fusion remain uncertain. Much evidence indicates that gating of ionic channels in the plasma membrane is an early consequence of antigenic challenge; calcium entry is implicated as an essential step, and membrane depolarization occurs even without calcium influx. So far, however, the evidence for channel activation is either indirect or of limited time-resolution. The goal of this project is to use the powerful technique of gigaseal patch-clamp recording to directly observe the operation of ionic channels in the plasma membrane of degranulating mast cells and rat basophilic leukemia cells. Channel types present in unstimulated cells will first be identified and characterized as to ion selectivity, voltage dependence, open time, unit conductance, and pharmacological profile. The contribution which these channels make to degranulation will then be assessed. Specific questions to be answered are: 1) Is the cross-linked Fc Epsilon receptor an ion channel and, if so, what is its ion specificity? 2) Does bridging of Fc Epsilon receptors generate an intracellular second messenger which gates channel activity in other proteins? 3) How is Ca influx related to membrane depolarization, i.e., does the same or a different channel mediate the two events? 4) Is channel inactivation responsible for the phenomenon of desensitization? 5) Do specific channel blockers prevent exocytosis and, if so, at what points do they interfere with the biochemistry of degranulation? In a related study, the mechanism of electric field-induced serotonin release from rat basophilic leukemia cells will be examined. The long-term objective of this work is to understand the nature of transmembrane signaling devices within the immune system.