Novel Roles for COX Assembly Factors in Mitochondrial Homeostasis

COX 组装因子在线粒体稳态中的新作用

• 批准号: RGPIN-2017-04216
• 负责人: Glerum, DMoira
• 金额: $ 1.89万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=652008
• 关键词: Novel; Roles; COX; Assembly; Factors

Mitochondria are sub-cellular compartments responsible for producing the bulk of the energy our cells need for survival. In addition to their central role in energy production, mitochondria are crucial for programmed cell death, an important component of the life-death balance for every living cell. My lab is focusing on cytochrome oxidase (COX), the terminal electron acceptor of the mitochondrial respiratory chain, the energy-producing machinery. In addition to its protein subunits, COX also requires a host of accessory proteins that provide copper and heme A for enzyme assembly. In the most recent granting period, we have found that Cox17 is more abundant in wild-type stationary phase yeast and that loss of Cox17 results in an inability to induce apoptosis in stationary phase yeast, suggesting for the first time that this small protein, better known as a mitochondrial copper chaperone, may also have role in cellular quality control. In addition, we have found that a lack of assembled COX also leads to an increase in oxidative stress.******In the coming granting period, we will continue using the yeast, Saccharomyces cerevisiae, as a model for studying the consequences of a COX assembly defect in both the mitochondrial and broader cell context. Yeast has proven to be an excellent model for better understanding how mitochondria are formed and function, with direct application to our understanding of human diseases that involve dysfunctional mitochondria, such as neurodegeneration and cancers. Our use of stationary phase yeast, which have ceased growing and dividing, is particularly relevant to understanding the consequences of mitochondrial defects in diseases involving human tissues that have ceased growing and dividing, such as neurons. Using standard approaches in yeast molecular cell biology and biochemistry and taking advantage of our large mutant collection, we will determine how Cox17 acts in the induction of apoptosis and what other molecules are involved in this novel function for Cox17. We will also determine the molecular basis for the increased abundance of Cox17 at stationary phase and how a loss of COX assembly leads to changes in the amount of protein and enzymatic activity of the Cu,Zn-superoxide dismutase in stationary phase yeast.******The proposed experiments are the continuation of the long-standing NSERC-funded program in my lab and will improve our understanding of the cellular consequences of COX assembly defects, as well as having direct relevance to our understanding of the molecular bases for inherited human COX deficiencies. This work will also have implications for our understanding of the etiologies and pathophysiology underlying neurodegenerative diseases and cancer, given that stationary phase yeast are an appropriate model for the terminally differentiated tissues typically involved in these human diseases.**

线粒体是亚细胞区室，负责产生细胞生存所需的大部分能量。线粒体除了在能量生产中发挥核心作用外，对程序性细胞死亡也至关重要，是每个活细胞生死平衡的重要组成部分。我的实验室主要研究细胞色素氧化酶（COX），它是线粒体呼吸链的终端电子受体，是能量产生的机器。除了其蛋白质亚基外，COX还需要一系列辅助蛋白，为酶组装提供铜和血红素a。在最近的研究中，我们发现Cox17在野生型固定期酵母中更丰富，并且Cox17的缺失导致固定期酵母无法诱导细胞凋亡，这首次表明这种小蛋白，也被称为线粒体铜伴侣蛋白，也可能在细胞质量控制中发挥作用。此外，我们发现缺乏组装的COX也会导致氧化应激的增加。******在即将到来的授权期内，我们将继续使用酵母（Saccharomyces cerevisiae）作为模型，研究COX组装缺陷在线粒体和更广泛的细胞背景下的后果。酵母已被证明是一个很好的模型，可以更好地理解线粒体的形成和功能，并直接应用于我们对涉及功能失调线粒体的人类疾病的理解，如神经变性和癌症。我们使用停止生长和分裂的固定相酵母，这对于理解线粒体缺陷在涉及停止生长和分裂的人体组织（如神经元）的疾病中的后果特别相关。利用酵母分子细胞生物学和生物化学的标准方法，并利用我们大量的突变体收集，我们将确定Cox17如何在诱导细胞凋亡中起作用，以及Cox17的这种新功能涉及哪些其他分子。我们还将确定在固定阶段Cox17丰度增加的分子基础，以及COX组装的损失如何导致固定阶段酵母中Cu， zn -超氧化物歧化酶的蛋白质量和酶活性的变化。******拟议的实验是我实验室长期以来nserc资助项目的延续，将提高我们对COX组装缺陷的细胞后果的理解，以及与我们对遗传性人类COX缺陷的分子基础的理解直接相关。这项工作也将对我们对神经退行性疾病和癌症的病因学和病理生理学的理解产生影响，因为固定期酵母是这些人类疾病中典型的终末分化组织的合适模型