Understanding how the mitochondrial phosphatase PGAM5 regulates mitochondrial dynamics

了解线粒体磷酸酶 PGAM5 如何调节线粒体动力学

• 批准号: RGPIN-2021-03460
• 负责人: McQuibban, George
• 金额: $ 2.33万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742565
• 关键词: Understanding; how; mitochondrial; phosphatase; PGAM5

Background: Mitochondria are the powerhouse of the cell and are critical mediators of cellular life and death. Many signalling and metabolic pathways are dependent on mitochondrial activity and impact function. One aspect of mitochondrial biology that remains enigmatic is the compelling membrane dynamics that occur within and between mitochondria. Individual units are constantly undergoing membrane fusion and fission reactions, the overall reason for this activity remains unknown. My lab has had a long-standing interest in mitochondrial dynamics, and we have been uncovering proteins and mechanisms that act as regulators. One particularly interesting protein is called PGAM5. PGAM5 is a phosphatase that exists in two isoforms, a long isoform (l-PGAM5) with a mitochondrial targeting and membrane binding motif and a short isoform (s-PGAM5) in which the N-terminus has been removed. It is not currently understood if the isoforms have different functions, but we have recently obtained preliminary data to suggest they have very different roles in regulating mitochondrial membrane dynamics. Hypothesis: l-PGAM5 and s-PGAM5 have both different localizations within mitochondria and regulate different aspects of mitochondrial fusion and fission. Specific aims: 1) Using a variety of cell biological and biochemical approaches, we will determine the inter-organelle localization of the two isoforms of PGAM5, both during cellular homeostasis, and during time of stress when mitochondrial membrane dynamics are required for cellular survival. 2) We will characterize and compare the interactome of the two PGAM5 isoforms using the BioID approach. Lists of potential interactors will be rationalized and validated with secondary approaches including IP and PLA analyses. Our studies should reveal important mechanistic insights into the function of PGAM5 in mitochondrial dynamics. Characterizing differing localizations and protein interactomes should highlight the molecular details of how PGAM5 contributes to mitochondrial biology. In sum these studies should help us to understand the reasons for mitochondrial dynamics as a fundamental aspect of cell biology that is conserved across all eukaryotes.

背景：线粒体是细胞的发电站，是细胞生死的关键介质。许多信号传导和代谢途径依赖于线粒体活性和影响功能。线粒体生物学的一个方面仍然是谜，是线粒体内和线粒体之间发生的引人注目的膜动力学。个别单位不断地进行膜融合和裂变反应，这种活动的总体原因仍然未知。我的实验室对线粒体动力学有着长期的兴趣，我们一直在探索作为调节剂的蛋白质和机制。一种特别有趣的蛋白质被称为PGAM 5。PGAM 5是以两种同种型存在的磷酸酶，即具有线粒体靶向和膜结合基序的长同种型（l-PGAM 5）和其中N-末端已被去除的短同种型（s-PGAM 5）。目前还不清楚这些亚型是否具有不同的功能，但我们最近获得的初步数据表明它们在调节线粒体膜动力学方面具有非常不同的作用。假设：l-PGAM 5和s-PGAM 5在线粒体内具有不同的定位，并且调节线粒体融合和分裂的不同方面。具体目标：1）使用多种细胞生物学和生物化学方法，我们将确定PGAM 5的两种亚型在细胞内稳态期间以及在细胞存活需要线粒体膜动力学的应激时间期间的细胞器间定位。2)我们将使用BioID方法表征和比较两种PGAM 5亚型的相互作用组。潜在相互作用者的列表将合理化，并通过次要方法（包括IP和PLA分析）进行验证。我们的研究应该揭示重要的机制的见解PGAM 5在线粒体动力学的功能。表征不同的定位和蛋白质相互作用组应该突出PGAM 5如何有助于线粒体生物学的分子细节。总之，这些研究应该有助于我们理解线粒体动力学作为细胞生物学的一个基本方面，在所有真核生物中保守的原因。