Phosphoinositide 3-Kinase Function in Lymphocytes

描述（由申请人提供）：本项目的长期目标是 定义磷酸肌醇3-激酶（PI 3 K）信号转导机制， 淋巴细胞由于PI 3 K是淋巴细胞增殖所必需的，因此， 该领域可能会导致新的策略，用于治疗免疫缺陷， 自身免疫、移植排斥和癌症。核心假设指导 这种应用是PI 3 K调节同种型p85 α和p85 β具有 在淋巴细胞信号传导中的不同功能作用。为了验证这个假设， 这个调查员？的实验室已经培育出缺乏p85 α或 p85 β。p85 α缺陷小鼠表现出与所见相似的B细胞缺陷 在缺乏Btk、BLNK或PLC γ 2的小鼠中。这些发现支持了一个模型， PI 3 K活化对于信号复合物的膜组装是重要的， 促进PLC γ 2激活和持续的钙流。T细胞和B 细胞依赖于不同的蛋白质来执行许多信号步骤， 将抗原受体与钙流和增殖联系起来。比如说， T细胞中的钙流受Itk（Btk的功能同源物）调节。 初步结果表明，p85 β可能是一个重要的PI 3 K调节因子。 T细胞信号传导中的同种型。本申请有三个具体目标：目标1是 为了检验p85 α是Btk和PLC γ 2激活所必需的模型， 导致持续的Ca 2+通量。将使用生化测定来分析 在缺乏p85 α的原代B细胞和永生化B细胞系中的信号传导。 目的二是确定p85 β是否是T细胞增殖和细胞因子分泌所必需的 生产目的3是确定p85 β是否是激活 Itk、PLC γ 1和T细胞中持续的Ca 2+通量。生化分析将是 用于分析纯化的T细胞中的信号传导。这些研究将增加我们的 了解PI 3 K信号传导，淋巴细胞的中心控制点 增殖

DESCRIPTION (provided by applicant): The long-range goal of this project is to define the mechanism of phosphoinositide 3-kinase (PI3K) signaling in lymphocytes. As PI3K is required for lymphocyte proliferation, advances in this area may lead to novel strategies for the treatment of immunodeficiency, autoimmunity, transplant rejection and cancer. The central hypothesis guiding this application is that the PI3K regulatory isoforms p85alpha and p85beta have distinct functional roles in lymphocyte signaling. To test this hypothesis, this investigator?s laboratory has generated mice lacking either p85alpha or p85beta. p85alpha-deficient mice exhibit B cell defects similar to those seen in mice lacking Btk, BLNK or PLCgamma2. These findings support a model that PI3K activation is important for membrane assembly of a signaling complex that facilitates PLCgamma2 activation and sustained calcium flux. T cells and B cells rely on distinct proteins to carry out many of the signaling steps that link the antigen receptor to calcium flux and proliferation. For example, calcium flux in T cells is regulated by Itk, a functional homolog of Btk. Preliminary results suggest that p85beta may be an important PI3K regulatory isoform in T cell signaling. This application has three specific aims: Aim 1 is to test the model that p85alpha is required for activation of Btk and PLCgamma2 leading to sustained Ca2+ flux. Biochemical assays will be used to analyze signaling in primary B cells and immortalized B cell lines lacking p85alpha. Aim 2 is determine if p85beta is required for T cell proliferation and cytokine production. Aim 3 is to determine whether p85beta is required for activation of Itk, PLCgamma1, and sustained Ca2+ flux in T cells. Biochemical assays will be used to analyze signaling in purified T cells. These studies will increase our understanding of PI3K signaling, a central control point in lymphocyte proliferation.