ION CHANNELS AND SIGNALING MECHANISMS IN T LYMPHOCYTES

T 淋巴细胞中的离子通道和信号传导机制

• 批准号: 6386034
• 负责人: RICHARD S LEWIS
• 金额: $ 35.67万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6386034
• 关键词: T cell receptor; T lymphocyte; biological signal transduction; calcium channel; calcium flux; cell membrane; chemical kinetics; clone cells; confocal scanning microscopy; electrophysiology; endocytosis; flow cytometry; gene induction /repression; human tissue; leukocyte activation /transformation; mitochondria; potassium channel; protein kinase; reporter genes; tissue /cell culture; transcription factor; video microscopy; voltage /patch clamp; western blottings

DESCRIPTION (Adapted from applicant's Description): The elevation of intracellular free Ca2+ concentration is an essential signal controlling the differentiation and functions of T lymphocytes. The long-term goal of this proposal is to elucidate the molecular mechanisms responsible for generating the shaping Ca2+ signals in T Cells. Ca2+ signals in T cells are generated to a great extent by the activity of Ca2+ release-activated Ca2+ (CRAC) channels. These channels open in response to the depletion of intracellular Ca2+ stores, but the mechanism linking store depletion to channel opening is not well understood. We will test two possible mechanisms of CRAC channel activation using a combination of electrophysiological and fluorescence imaging approaches: regulated insertion of open channels into the plasma membrane by vesicle fusion, and control of CRAC channel gating by physical coupling to store membrane proteins. Mitochondria play an essential role in maintaining a high rate of Ca2+ influx through CRAC channels. To further understand how this function is carried out, we will examine the functional interactions between mitochondria and both CRAC channels and Ca2+-activated K+ channels, and relate this to the control of membrane potential and Ca2+ influx. Finally, Ca2+ ATPases in the plasma membrane (PMCA) are primarily responsible for the clearance of Ca2+ from T cells, and their activity is modulated slowly by changes in [Ca2+], allowing them to contribute to the complexity of Ca2+ signaling dynamics. We will apply a novel cytosolic calcium clamp technique to characterize the Ca2+- and time-dependence of PMCA modulation and its molecular mechanism. The significance of these studies is two-fold. First, CRAC channels, KCa channels, mitochondria, and pumps are widely expressed in various forms among non-excitable cells, so that a better understanding of their operation and interactions in T cells will shed light on Ca2+ signaling mechanisms in many cell types. Second, the complex nature of Ca2+ signals in T cells is known to be an important determinant for the selective regulation of downstream responses such as gene expression and cell activation during the immune response. Thus, the results of this study may help identify novel targets for the control of the immune response. Thus, the results of this study may help identify novel targets for the control of the immune response that may be beneficial in treating autoimmune disorders of immunodeficiencies, and they may help to explain immune dysfunctions resulting from the abberrant operation of channels, pumps and mitochondria.

描述（改编自申请人的描述）： 细胞内游离Ca~（2+）浓度是一个重要的信号， T淋巴细胞的分化和功能。长期目标是 建议是阐明负责产生的分子机制 在T细胞中塑造Ca2+信号。T细胞中的Ca2+信号被产生为 在很大程度上通过Ca2+释放激活的Ca2+通道（CRAC）的活性。 这些通道响应于细胞内Ca2+储存的耗尽而打开， 但存储耗尽与沟道开放之间的联系机制尚不清楚 明白我们将测试CRAC通道激活的两种可能机制 使用电生理学和荧光成像的组合 方法：调节开放通道插入质膜， 囊泡融合，并通过物理偶联来控制CRAC通道门控， 储存膜蛋白。线粒体在维持一种 通过CRAC通道的高速率Ca2+内流。为了进一步了解 功能执行后，我们将检查功能之间的相互作用 线粒体和CRAC通道和Ca2+激活的K+通道，并与 这与膜电位和Ca~（2+）内流的调控有关。最后，Ca2 + 质膜中的ATP酶（PMCA）主要负责细胞膜的形成。 从T细胞中清除Ca2+，并且它们的活性通过 [Ca2 +]的变化，使它们有助于Ca2+的复杂性 信号动力学我们将应用一种新的细胞溶质钙钳夹技术， 表征PMCA调制的Ca 2+和时间依赖性及其分子 机制 这些研究的意义是双重的。首先，CRAC通道，KCa通道， 线粒体和泵在非兴奋细胞中以各种形式广泛表达， 因此，更好地了解它们在T细胞中的运作和相互作用将有助于阐明 在许多细胞类型中的Ca2+信号机制。第二，Ca2+信号的复杂性 在T细胞中，已知是选择性调节下游免疫应答的重要决定因素。 在免疫应答过程中，基因表达和细胞活化等反应。因此，在本发明中， 这项研究的结果可能有助于确定控制免疫反应的新靶点。 因此，这项研究的结果可能有助于确定新的目标，为控制免疫 可能有益于治疗免疫缺陷的自身免疫性疾病的应答， 它们可能有助于解释由于免疫系统的异常运作而导致的免疫功能障碍。 通道泵和线粒体