4PS MEDIATED SIGNALING PATHWAY IN IL4 SYSTEM

本修订提案(L R29 AI38456-OL)侧重于分子 剖析4PS介导的IL-4信号转导途径。4Ps是一个180 kDa 在IL-4刺激过程中被酪氨酸磷酸化的蛋白质。 最近，4PS蛋白被纯化，并分离出它的全长基因。初步 数据直接证明了4PS在LL-4中的重要作用 发信号。对4PS介导的IL-1信号转导通路的全面认识 4系统具有重要的科学和临床意义，因为IL-4在 在保护性免疫反应的调节中起关键作用 通过自身免疫限制组织损伤，并在免疫消除中 某些肿瘤细胞。IL-4还控制B细胞中Ig类的转换 从IgM到IgG1(人类的IgG4)和IgE，这是普遍存在的 患有过敏性疾病，如哮喘和花粉热。了解 IL-4信号转导的分子机制可能为 控制和干预这些病理生理过程。 IL-4信号系统参与酪氨酸激酶的激活， 4PS的磷酸化和转录因子的激活； 然而，对IL-4作出反应而使4PS磷酸化的激酶却没有 已经确定，与核事件有关的信号还没有被识别出来 已经成立了。这项提议使用最近克隆的4PS分子来 研究IL-4受体复合体4PS之间的分子联系 4PS的磷酸化和转录因子的激活 IL-4信号转导。以下具体目标将定义和探索 未来五年IL-4信号系统中的元素是 由4PS控制。 1.白介素4受体复合体与4PS相互作用的机制 将通过合理设计的4PS突变分析进行研究 和IL-4受体的阿尔法亚单位。 2.使4PS(4PS激酶)磷酸化的酪氨酸激酶 通过细胞质和细胞膜的分级来鉴定对IL-4的作用 蛋白质，并对其进行了表征。激酶在白介素4中的重要性 将对信令进行调查。 3.4PS的磷酸化与激活之间的关系 流感信号通路中的转录因子将被建立。 4PS在表达IL-4α亚基的32D细胞中的过表达 受体将允许识别潜在的4PS介导的 可能参与IL-4诱导的细胞转录因子(4PS-Tf) 增殖或分化。

This revised proposal (l R29 AI38456-Ol) focuses on the molecular dissection of 4PS-mediated pathways in lL-4 signaling. 4PS is a 180 kDa protein that becomes tyrosine phosphorylated during IL-4 stimulation. Recently, 4PS protein was purified and its cDNA was isolated. Preliminary data directly demonstrated that 4PS plays an important role in lL-4 signaling. A full understanding of 4PS-mediated signaling pathways in IL- 4 system is scientifically and clinically important because IL-4 plays a crucial role in the regulation of protective immune responses, in limiting tissue damage by autoimmunity, and in immune elimination of certain tumor cells. IL-4 also controls the Ig class switching in B cells from IgM to IgGl (IgG4 in human) and to IgE, which is commonly associated with allergic diseases such as asthma and hay fever. Understanding the molecular mechanisms of IL-4 signaling may provide opportunities for controlling and intervening in these pathophysiological processes. IL-4 signaling system is involved in the activation of tyrosine kinases, phosphorylation of 4PS, and the activation of transcription factors; however, the kinase that phosphorylates 4PS in response to IL-4 has not been identified, and the signals linking to nuclear events have not been established. This proposal uses the recently cloned 4PS molecule to investigate the molecular linkage between the IL-4 receptor complex, 4PS kinase, phosphorylation of 4PS and activation of transcription factors in IL-4 signaling. The following specific aims will define and explore over the next five years elements in the IL-4 signaling system that are controlled by 4PS. 1. The mechanism of interaction between the IL-4 receptor complex and 4PS will be investigated by a rationally designed mutational analysis of 4PS and the alpha subunit of the IL-4 receptor. 2. The tyrosine kinases that phosphorylate 4PS (4PS kinase) in response to IL-4 will be identified by fractionation of cytoplasmic and membrane proteins, and characterized. The importance of the kinase in IL-4 signaling will be investigated. 3. The connection between phosphorylation of 4PS and the activation of transcription factors in flu signaling pathway will be established. Overexpressing 4PS in 32D cells expressing the alpha subunit of the IL-4 receptors will allow the identification of potential 4PS-mediated transcription factors (4PS-TF) that may be involved in IL-4-induced cell proliferation or differentiation.