Controlling mitochondrial bioenergetics with protein S-glutathionylation redox switches

用蛋白质 S-谷胱甘肽氧化还原开关控制线粒体生物能

• 批准号: RGPIN-2016-04829
• 负责人: Mailloux, Ryan
• 金额: $ 2.62万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708923
• 关键词: Controlling; mitochondrial; bioenergetics; protein; glutathionylation

Mitochondria are required to furnish mammalian cells with ATP, a usable form of energy that performs useful “work” in a cell. ATP is generated by oxidative phosphorylation (OXPHOS) which couples the energy released from nutrient metabolism to the phosphorylation of ADP. Akin to an electrical wire, electrons liberated from nutrients are ferried through electron conducting protein complexes to molecular oxygen (O2) at the end of the chain. Electron movement to O2 is a “favorable process” which means that electron movement releases energy that can be trapped for the production of ATP. Unfortunately OXPHOS is not a perfect process and sometimes electrons can “leak” out of the chain and prematurely interact with O2 generating reactive oxygen species (ROS). ROS are dangerous at high quantities but low amounts are required to coordinate mitochondrial functions with changes in cell physiology. Indeed, ROS are required to drive basic cellular functions ranging from cell proliferation to wound healing and heart function. What is truly surprising is that despite 50 years of research we only have a rudimentary understanding of how mitochondria control ROS formation. Given its dichotomy, it would seem quite important to decipher how mitochondria modulate how much ROS is produced. One way to control ROS is with endogenous antioxidants like glutathione (GSH) which is found at high levels in mitochondria. Another way is with redox switches which can control the entry and exit of electrons from sites of ROS production. One switch that has gained a lot of attention is protein S-glutathionylation (PGlu) which involves the physical attachment and removal of GSH from enzymes. PGlu reactions are attractive switches for controlling mitochondrial OXPHOS and ROS production since the switches themselves are directly influenced by how much GSH is interacting with ROS. My long term research focus is to provide the first in depth assessment of the function of PGlu in controlling mitochondrial bioenergetics and ROS production. The overall goal is to enhance our understanding of how this redox switch controls the production of an important signaling molecule, ROS. This includes identifying which enzymes are controlled by PGlu and the impact it has on OXPHOS and ROS formation at these specific sites. This would be the first research program in Canada that dissects the function of redox switches in controlling mitochondrial metabolism and ROS formation. It also broaches for the first time the function of redox switches in controlling the assembly of mitochondrial proteins involved in ROS formation. The redox biology field is a new field filled with exciting and dynamic research and it is thus anticipated that the novelty of this research program will significantly advance our understanding of the role of redox switches in controlling mitochondria and ROS signaling.

哺乳动物细胞需要线粒体提供ATP， ATP是一种可用的能量形式，在细胞中完成有用的“工作”。ATP是由氧化磷酸化（OXPHOS）产生的，它将营养代谢释放的能量与ADP的磷酸化结合在一起。类似于电线，从营养物质中释放出来的电子通过电子传导蛋白复合物传递到链末端的分子氧（O2）。电子向O2的运动是一个“有利的过程”，这意味着电子运动释放的能量可以被捕获以产生ATP。不幸的是，OXPHOS并不是一个完美的过程，有时电子会从链中“泄漏”出来，过早地与O2产生活性氧（ROS）相互作用。大量的活性氧是危险的，但需要少量的活性氧来协调线粒体功能和细胞生理变化。事实上，从细胞增殖到伤口愈合和心脏功能，ROS是驱动基本细胞功能所必需的。真正令人惊讶的是，尽管经过了50年的研究，我们对线粒体如何控制活性氧的形成只有初步的了解。鉴于其二分法，破译线粒体如何调节活性氧的产生似乎非常重要。控制活性氧的一种方法是使用内源性抗氧化剂，如谷胱甘肽（GSH），它在线粒体中含量很高。另一种方法是使用氧化还原开关，它可以控制电子从ROS产生位点的进入和退出。一个引起了广泛关注的开关是蛋白质s -谷胱甘肽酰化（PGlu），它涉及酶的物理附着和谷胱甘肽的去除。PGlu反应是控制线粒体OXPHOS和ROS产生的有吸引力的开关，因为开关本身直接受到GSH与ROS相互作用的多少的影响。我的长期研究重点是提供PGlu在控制线粒体生物能量学和ROS产生方面的功能的首次深入评估。总体目标是增强我们对氧化还原开关如何控制重要信号分子ROS的产生的理解。这包括确定哪些酶是由PGlu控制的，以及它对这些特定位点的OXPHOS和ROS形成的影响。这将是加拿大首个剖析氧化还原开关在控制线粒体代谢和ROS形成中的功能的研究项目。它还首次揭示了氧化还原开关在控制参与ROS形成的线粒体蛋白组装中的功能。氧化还原生物学领域是一个充满令人兴奋和动态研究的新领域，因此预计该研究计划的新颖性将大大促进我们对氧化还原开关在控制线粒体和ROS信号传导中的作用的理解。