Role of Mitophagy in Mitochondrial Protein Quality Control

项目摘要/摘要 线粒体功能障碍经常发生在老年人身上，是疾病的标志，如 帕金森氏症、阿尔茨海默氏症、癌症和糖尿病。生物体都有应对能力的机制 线粒体功能障碍，包括促进溶酶体翻转的PINK1-Parkin途径 线粒体蛋白通过自噬(有丝分裂)反应线粒体功能障碍。然而，有一个 在理解该途径如何发挥作用以促进线粒体完整性和防止 疾病的形成。这项申请的目标是确定损害通过的机制- 利用酿酒酵母诱导的有丝分裂促进线粒体质量控制。以前的研究发现， 酵母中的有丝分裂吞噬途径，但该途径不与PINK1-Parkin途径同源，也不 对线粒体功能障碍做出反应，这限制了其作为模型系统的实用性。最近的申请者 在酵母中发现了第二条在功能上与PINK1-Parkin途径相同的有丝分裂途径 并促进有丝分裂反应，以应对由溶酶体丢失引起的年龄诱导的线粒体功能障碍- 比如液泡酸度。申请者将使用这一新途径来检验本申请的中心假设 这种有丝分裂选择性地改变线粒体蛋白质组以维持线粒体的完整性 线粒体功能障碍。了解有丝分裂如何防止酵母线粒体功能障碍 迅速促进我们对人类这一过程的理解，并促进治疗方法的发展 与线粒体功能障碍相关的疾病。此应用程序的目标将通过以下方式实现 追求以下三个具体目标：目标1：确定空泡酸度降低是如何导致 线粒体功能障碍。抑制子筛选和营养调节将被用来表征通路 在缺乏空泡酸性的情况下，这会导致线粒体功能障碍。目标2：确定如何 线粒体蛋白质被有丝分裂降解。这一目标将使用基于显微镜的有丝分裂试验和 进一步鉴定损伤诱导的有丝分裂吞噬途径和鉴定新基因的质谱仪 它的功能是必需的。目的3：确定线粒体的哪些成分被有丝分裂降解。这 AIM将使用基于显微镜的技术来鉴定因有丝分裂和 确定有丝分裂是以先前存在的蛋白质还是新合成的蛋白质为目标。这项研究中提出的 应用程序是创新的，因为它剖析了有丝分裂在线粒体质量控制中的作用 之前未知的PINK1-Parkin通路在萌芽酵母中的功能等价物，因此带来了 酵母菌遗传学对损伤诱导的有丝分裂领域的作用。这一点意义重大，因为它将提供 深入理解保护细胞免受病毒侵害的线粒体蛋白质质量控制途径 年龄导致线粒体功能障碍，并防止帕金森氏病的发展。

PROJECT SUMMARY/ABSTRACT Mitochondrial dysfunction frequently occurs in aged individuals and is a hallmark of diseases such as Parkinson's, Alzheimer's, cancer, and diabetes. Organisms are equipped with mechanisms to cope with mitochondrial dysfunction, including the PINK1-Parkin pathway that promotes lysosomal turnover of mitochondrial proteins by autophagy (mitophagy) in response to mitochondrial dysfunction. However, there is a fundamental gap in understanding how this pathway functions to promote mitochondrial integrity and prevent disease formation. The objective of this application is to determine the mechanism through which damage- induced mitophagy promotes mitochondrial quality control using S. cerevisiae. Previous studies identified a mitophagy pathway in yeast, but this pathway is not homologous to the PINK1-Parkin pathway and does not respond to mitochondrial dysfunction, which limits its usefulness as a model system. The applicant recently discovered a second mitophagy pathway in yeast that is functionally equivalent to the PINK1-Parkin pathway and promotes mitophagy in response to age-induced mitochondrial dysfunction caused by loss of lysosome- like vacuolar acidity. The applicant will use this novel pathway to test the central hypothesis of this application that mitophagy selectively alters the mitochondrial proteome to maintain mitochondrial integrity in response to mitochondrial dysfunction. Understanding how mitophagy prevents mitochondrial dysfunction in yeast will rapidly advance our understanding of this process in humans and facilitate the development of treatments for diseases associated with mitochondrial dysfunction. The objective of this application will be accomplished by pursuing the following three specific aims: Aim 1: Determine how reduced vacuolar acidity causes mitochondrial dysfunction. Suppressor screens and nutrient modulation will be used to characterize pathways that contribute to mitochondrial dysfunction in the absence of vacuolar acidity. Aim 2: Determine how mitochondrial proteins are degraded by mitophagy. This aim will use a microscopy-based mitophagy assay and mass spectrometry to further characterize the damage-induced mitophagy pathway and identify novel genes required for its function. Aim 3: Identify what components of the mitochondria are degraded by mitophagy. This aim will use microscopy-based techniques to identify mitochondrial proteins degraded by mitophagy and determine if mitophagy targets preexisting or newly synthesized proteins. The research proposed in this application is innovative because it dissects the role of mitophagy in mitochondrial quality control using a previously unknown functional equivalent of the PINK1-Parkin pathway in budding yeast and thus brings the power of yeast genetics to the damage-induced mitophagy field. This is significant because it will provide a deep molecular understanding of a mitochondrial protein quality control pathway that protects cells against age-induced mitochondrial dysfunction and prevents the development of Parkinson's disease.