ION CHANNELS AND SIGNALING MECHANISMS IN T LYMPHOCYTES

描述（改编自研究者的申请）： 抗原引起的细胞内游离钙浓度在 决定T淋巴细胞的命运和功能。 的长期目标 这一建议是为了阐明产生和调节 钙信号，并了解它如何激活特定的T细胞 激活基因 过去五年的研究表明， T细胞中的信号传导由容量性Ca 2+进入维持，这是一种广泛的 细胞内Ca 2+储存耗尽的信号机制 通过Ca 2+释放激活的Ca 2+（CRAC）通道激活Ca 2+内流。 关于这些渠道是如何监管的，以及如何监管， 它们的活性决定诸如T细胞活化或耐受性的应答。 提出了四个具体目标来阐明调控和功能 CRAC通道的T细胞使用显微成像和 膜片钳技术：1）测定CRAC通道依赖性 激活细胞内钙离子和钙库含量。 2)探讨 细胞内Ca 2+反馈缓慢抑制CRAC的机制 渠道 3)确定线粒体在调节Ca 2+中的作用 信号并测试它们通过以下方式影响CRAC通道功能的假设： 干扰缓慢失活。 4)检查[Ca 2 +]i的作用 在提高效率和/或特异性方面的振荡 转录反应，使用报告基因驱动的两个Ca 2+敏感 转录因子、NFAT和AP-1。 这些研究的意义在于，它们将首次描述 时间的几个细胞过程，控制动态行为的 耗尽激活的Ca 2+通道。 此外，在许多细胞中， 动态Ca 2+信号的后果，如振荡，在很大程度上是 这些研究将评估它们对一个可定义的 生理学上重要的终点基因激活。 鉴于要求 对于CRAC通道在T细胞活化中的功能，这些研究最终可能 暴露了一些免疫反应的控制点，导致新的 免疫调节策略，具有重要的治疗益处， 预防或治疗疾病如AIDS和自身免疫性疾病。

DESCRIPTION (Adapted from the investigator's application): The elevation of intracellular free calcium concentration by antigen plays a pivotal role in determining the fate and functions of T lymphocytes. The long term goals of this proposal are to elucidate the mechanisms that generate and regulate the calcium signal, and to understand how it activates specific T-cell activation genes. Work over the past five years indicates that Ca2+ signaling in T cells is sustained by capacitative Ca2+ entry, a widespread signaling mechanism by which the depletion of intracellular Ca2+ stores activated Ca2+ entry through Ca2+ release-activated Ca2+ (CRAC) channels. Relatively little is known about how these channels are regulated and how their activity determines responses such as T-cell activation or tolerance. Four specifics aims are proposed to elucidate the regulation and functions of CRAC channels in T cells using a combination of microscopic imaging and patch-clamp techniques: 1) Determine the dependence of CRAC channel activation on store content and intracellular Ca2+. 2) Investigate the mechanism by which intracellular Ca2+ feeds back to slowly inactivate CRAC channels. 3) Establish the role of mitochondria in modulating the Ca2+ signal and test the hypothesis that they influence CRAC channel function by interfering with slow inactivation. 4) Examine the role of [Ca2+]i oscillations in increasing the efficiency and/or the specificity of transcriptional responses, using reporter genes driven by two Ca2+-sensitive transcriptions factors, NFAT and AP-1. The significance of these studies is that they will describe for the first time several cellular processes that control the dynamic behavior of depletion-activated Ca2+ channels. Moreover, in many cells the specific consequences of dynamic Ca2+ signals such as oscillations has been largely unexplored, and these studies will assess their impact on a definable and physiologically important end point, gene activation. Given the requirement for CRAC channel function in T-cell activation, these studies may ultimately expose a number of control points for the immune response, leading to new strategies for immunomodulation with important therapeutic benefit in the prevention or treatment of disorders such as AIDS and autoimmune disease.