Role of Prohibitin Nitrosylation in its Neuroprotective Functions

项目摘要/摘要 线粒体蛋白Prohibitin(PHB)是生命所必需的。它对细胞活动的重要性 事实证明，PHB的缺失对小鼠是胚胎致死的，而且到目前为止没有 在任何神经系统疾病中都发现了PHB编码区的突变， 这表明PHB的完整性是必不可少的，而体细胞突变是有害的。我们最近 研究表明，PHB对脑缺血具有显著的神经保护作用 脑损伤与潜在的线粒体相关机制。它的表达对于 线粒体在应激状态下的功能。然而，这种重要的蛋白质是如何稳定在 在神经保护中受到功能调节，以及它是如何被调节的 在其他神经疾病中的调节失调，令人惊讶的是仍然未知。在探索 PHB的调节机制，我们发现PHB需要一氧化氮(NO)。 表达介导的神经保护。因此，我们研究了NO与NO之间的相互作用 和PHB，发现NO通过蛋白质S-亚硝化作用修饰PHB的翻译后，a 类似于蛋白质磷酸化的新的调控机制。在此应用程序中，我们建议 PHB S-亚硝化作用及其功能调节机制的研究 对PHB的影响较大。我们的中心假设是亚硝化对PHB的 神经保护功能，因此，PHB亚硝化障碍 有害的，有助于病理的。我们将使用一种新的突变敲入小鼠，In 其中PHB蛋白的唯一半胱氨酸残基被突变，使得PHB不能被亚硝化， 分析NO调节机制及PHB亚硝化缺失对PHB的影响 与线粒体结构相关的脑缺血损伤的功能 改装。三个具体目标将系统地检验这一假说。评选结果 拟议的研究将揭示PHB以前未被认识到的调节机制，我们 相信对于促进最终可能受益的潜在疗法的设计是至关重要的 有中风和其他神经疾病风险的患者。

Project Summary/Abstract The mitochondrial protein Prohibitin (PHB) is essential for life. Its importance to cellular activities is attested by the fact that deletion of PHB is embryonic lethal in mice and that to date no mutation has been found in the coding region of PHB in any neurological disease conditions, indicating that PHB integrity is essential and that somatic mutation is detrimental. Our recent work has demonstrated that PHB has remarkable neuroprotective potential against ischemic brain injury with an underlying mitochondrial associated mechanism. Its expression is critical for mitochondrial function in stress situations. However, how this important protein that are stable at both mRNA and protein levels, is functionally regulated in neuroprotection, as well as how it is dysregulated in other neurological conditions, remain surprisingly unknown. In exploring the mechanisms of PHB regulation, we discovered that nitric oxide (NO) is required for PHB expression mediated neuroprotection. Therefore, we investigated the interaction between NO and PHB and found that NO modifies PHB post-translationally, through protein s-nitrosylation, a novel regulatory mechanism similar to protein phosphorylation. In this application, we propose to study the effects of PHB S-nitrosylation and the mechanisms underlying functional regulation of PHB by NO. Our central hypothesis is that nitrosylation is critical for PHB’s neuroprotective function and, consequently, disturbances of PHB nitrosylation are detrimental and contribute to pathology. We will use a novel mutant knock-in mouse, in which the sole cysteine residue of PHB protein is mutated so that PHB cannot be nitrosylated, to analyze the mechanisms of NO regulation and the effects of loss of PHB nitrosylation on PHB function, in the settings of brain ischemic injury in association with mitochondria structural alterations. Three specific aims will systematically test the hypothesis. The results of the proposed studies will reveal a previously unrecognized regulatory mechanism of PHB which we believe is crucial to facilitate the design of potential therapies that could ultimately benefit patients at risk of stroke and other neurological diseases.