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

许多信号转导通路依赖于 激动剂诱导胞浆内游离钙升高。这个项目的初始阶段 反应通常是由于产生肌醇1，4，5-三磷酸和 随后从内质网(ER)释放钙离子。耗尽 导致细胞外钙内流至细胞内。 细胞质，称为容量型或储备型钙进入(SOCE)的过程。 SOCE与一系列显著的生物过程有关，包括T 细胞激活、胰岛素分泌、血管收缩和心脏 发展。出现了一种假说来解释病毒的传播 关于内质网钙离子耗竭到质膜的信息提示 一种新的扩散信使分子--钙内流因子的关键作用 (CLF)。在过去的一年里，这组人收集的数据 调查人员有力地支持了CIF存在的结论，即 它是在内质网钙储备库耗尽时合成的，它负责 激活两个不同的质膜钙通道。 CIF功能的成像和膜片钳技术提供了独特的和 关于哺乳动物CIF的独立验证数据。此外，该集团还拥有 确定在酵母中存在遗传缺陷的酿酒酵母 细胞器Ca~(2+)-ATPase也能产生迄今无法区分的CIF 它的哺乳动物的对应物。这种廉价而丰富的材料来源， CIF的提纯方案正在顺利进行，分析表明 已经开发出将这个群体放在一个独特的位置来净化和 对这种新颖的信号分子进行结构表征。实验也将 以确定在ER上产生CIF的生物合成途径 存储耗尽，并定义CIF激活这两个 参与SOCE的质膜钙通道。这一信息 我们获得的成果将应用于一个主要的健康问题，糖尿病，它 以SOCE的潜在损害为特征的。高血糖所致 氨基葡萄糖生物合成途径和/或蛋白激酶C的激活将 被调查为国有经济的可能监管者。所描述的方法将 涉及跨学科、多调查员的倡议，适用于 生物、生化和结构程序来解决这个问题。成功 这些研究的完成将提供有关SOCE的关键信息，并可能 定义糖尿病的新治疗目标。

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.