Defining the Allosteric Network of Stress-Responsive Mitochondrial Protease OMA1

项目总结 识别、耐受和应对压力的系统对长寿和细胞功能至关重要。作为城市的枢纽 在生物能量过程中，线粒体有一系列的应激耐受系统，其中之一由 蛋白水解酶定位于线粒体膜内层。IMM蛋白酶敏锐地管理压力，但 免疫球蛋白水解酶活性的慢性失衡与线粒体功能障碍有关 衰老和病因多样的年龄相关疾病，包括许多神经退行性疾病和 心肌病。值得注意的是，挽救和恢复免疫球蛋白水解酶活性平衡的干预措施 显示了治疗的益处，以减轻病理性线粒体功能障碍牵连的急性和 与年龄相关的慢性疾病以及寿命延长。这种多模式的治疗价值导致了 对确定驱动IMM蛋白水解酶功能的分子机制非常感兴趣。一个中心压力 目前尚未被研究的反应性IMM蛋白水解酶是不依赖于ATP的锌金属蛋白酶OMA1。 OMA1在基本不活跃的情况下，通过一种不明确的机制被激活，以响应线粒体的伤害。 活性OMA1定点切割特定IM底物以保护线粒体免受急性线粒体的伤害 通过调节形态和激活应激反应转录因子。尽管 OMA1在线粒体应激反应中的中枢作用及其高治疗价值 已经定义了OMA1激活或蛋白分解活性的信息。在这里，我们集成了低温电磁结构 确定(目标1)和深度突变扫描(目标2)以建立第一结构-功能关系 用于OMA1激活和蛋白水解性。通过这些努力，我们将确定其分子机制。 OMA1的活化和蛋白降解。这将揭示对OMA1依赖的线粒体调控的新见解 蛋白质平衡和功能，并建立结构基础，以开发新的治疗靶向策略 OMA1可缓解与衰老和衰老相关的病理性线粒体功能障碍 神经退行性变和心肌病。

PROJECT SUMMARY Systems to identify, endure, and respond to stress are critical for longevity and cellular function. As the hub of bioenergetic processes, mitochondria have an array of stress tolerance systems, one of which is comprised of proteases localized to the inner mitochondrial membrane (IMM). IMM proteases acutely manage stress, but chronic imbalances in the activity of IMM proteases contribute to mitochondrial dysfunction associated with ageing and etiologically-diverse age-associated diseases including many neurodegenerative disorders and cardiomyopathy. Remarkably, interventions to rescue and restore balance to IMM protease activity have demonstrated therapeutic benefit for mitigating pathologic mitochondrial dysfunction implicated in both acute and chronic age-associated diseases as well as lifespan extension. This multimodal therapeutic value has led to significant interest in defining the molecular mechanisms that drive IMM protease function. One central stress responsive IMM protease that remains understudied is the ATP-independent zinc metalloprotease OMA1. Basally inactive, OMA1 is activated in response to mitochondrial insults through a poorly defined mechanism. Active OMA1 site-specifically cleaves select IM substrates to protect mitochondria from acute mitochondrial insults through modulation of morphology and the activation of stress-responsive transcription factors. Despite the central role of OMA1 in mounting a mitochondrial stress response and its high therapeutic value, no structural information of OMA1 activation or proteolytic activity has been defined. Here, we integrate cryo-EM structure determination (Aim 1) and deep mutational scanning (Aim 2) to establish the first structure-function relationship for OMA1 activation and proteolytic activity. Through these efforts, we will define the molecular mechanism of OMA1 activation and proteolysis. This will reveal new insights into OMA1-dependent regulation of mitochondrial proteostasis and function and establish a structural basis to develop new strategies to therapeutically target OMA1 to mitigate pathologic mitochondrial dysfunction associated with ageing and ageing-associated neurodegeneration and cardiomyopathy.