CA INFLUX FACTOR-- STRUCTURE/FUNCTION & ROLE IN DIABETES

CA 流入因子——结构/功能

• 批准号: 6635146
• 负责人: Richard Banfield Marchase
• 金额: $ 32.29万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6635146
• 关键词: T lymphocyte; Xenopus oocyte; bioassay; biological information processing; biological signal transduction; calcium channel; calcium flux; carbohydrate biosynthesis; endoplasmic reticulum; hexosamines; human tissue; hyperglycemia; insulin dependent diabetes mellitus; interleukin 2; leukocyte activation /transformation; mass spectrometry; membrane transport proteins; nuclear magnetic resonance spectroscopy; protein biosynthesis; protein kinase C; protein structure function; tissue /cell culture; voltage /patch clamp

Numerous signal transduction pathways are dependent upon agonist-induced increases in cytoplasmic free Ca2+. The initial phase of this response is often due to the generation of inositol 1,4,5-trisphosphate and a subsequent release of Ca2+ from the endoplasmic reticulum (ER). The depletion of ER Ca2+ stores results in an influx of extracellular Ca2+ into the cytoplasm, a process termed capacitative or store-operated Ca2+ entry (SOCE). SOCE is implicated in a remarkable array of biological processes, including T cell activation, the secretion of insulin, vasoconstriction, and heart development. One hypothesis that has emerged to explain the transmission of information regarding ER Ca2+ depletion to the plasma membrane proposes a critical role for a novel diffusible messenger molecule, Ca2+ influx factor (ClF). In the last year data that have been gathered by this group of investigators provide strong support for the conclusion that CIF exists, that it is synthesized upon ER Ca2+ store depletion, and that it is responsible for activation of two distinct store-operated plasma membrane Ca2+ channels. Imaging and patch-clamp techniques for CIF's function have provided unique and independently verified data on mammalian CIF. In addition, this group has determined that Saccharomyces cerevisiae that are genetically deficient in an organellar Ca2+ ATPase also make a CIF that to date is indistinguishable from its mammalian counterpart. This inexpensive and plentiful source of material, the purification schemes for CIF that are well underway, and the assays that have been developed place this group in a unique position to purify and structurally characterize this novel signaling molecule. Experiments also will be performed to define the biosynthetic pathway for generating CIF upon ER Ca2+ store depletion, and to define the mechanism by which CIF activates the two plasma membrane Ca2+ + channels that contribute to SOCE. The information that we gain will be applied to a major health problem, diabetes, which mischaracterized by an underlying impairment of SOCE. The hyperglycemia-induced activation of the hexosamine biosynthetic pathway and/or protein kinase C will be investigated as possible regulators of SOCE. The described approach will involve a cross-disciplinary, multi-investigator initiative that applies biologic, biochemical, and structural procedures to this problem. Successful completion of these studies will provide pivotal information on SOCE and may define novel therapeutic targets for diabetes.

许多信号转导途径取决于 激动剂引起的细胞质游离Ca2+的增加。最初的阶段 反应通常是由于肌醇1,4,5-三磷酸盐和A的产生 随后从内质网（ER）中释放Ca2+。耗尽 ER Ca2+存储的储存导致细胞外Ca2+流入 细胞质，一种称为电容或储存的Ca2+进入（SOCE）的过程。 Soce与一系列出色的生物过程有关，包括T 细胞激活，胰岛素的分泌，血管收缩和心脏 发展。出现了一个假设来解释传播 有关ER Ca2+耗尽到质膜的信息提出了 新型扩散的使者分子Ca2+涌入因子的关键作用 （CLF）。在过去的一年中，这组收集的数据 调查人员为CIF存在的结论提供了大力支持，即 它是在ER Ca2+商店耗尽上合成的，并且负责 激活两个不同的储存质膜Ca2+通道的激活。 CIF功能的成像和贴片钳技术提供了独特的和 对哺乳动物CIF的独立验证数据。此外，这个小组有 确定酿酒酵母在遗传上缺乏 Orgralar Ca2+ ATPase还使CIF与迄今为止无法区分 它的哺乳动物对应物。这种廉价且丰富的材料来源， CIF的纯化方案正在进行中，并进行了测定 已经开发了该小组的独特位置，以净化和 结构表征了这种新型信号分子。实验也会 执行以定义在ER Ca2+上产生CIF的生物合成途径 存储耗竭，并定义CIF激活两者的机制 质膜Ca2 + +通道有助于SOCE。信息 我们收获将应用于主要的健康问题，即糖尿病，该问题 由SOCE的潜在损害误解了。高血糖引起的 己糖胺生物合成途径和/或蛋白激酶C的激活将 被调查为SOCE的可能调节剂。所描述的方法将 涉及适用于 解决此问题的生物学，生化和结构性程序。成功的 这些研究的完成将提供有关SOCE的关键信息，并且可以 定义糖尿病的新型治疗靶标。