An Interdisciplinary Approach to Stress-Induced Mitochondrial Quality Control

 描述(由申请人提供)：进行性线粒体损伤和由此导致的功能障碍是许多人类疾病的关键因素。真核细胞有一个多层次的损伤预防和反应系统。许多对人类和各种模型系统的研究都表明，线粒体蛋白质的降解是第一道防线。我们已经发现了一个以进化上保守的Vms1蛋白为中心的系统，该系统以应激反应的方式促进蛋白质从线粒体外膜上移除。我们提出了一个雄心勃勃的跨学科计划来描述该蛋白及其相关蛋白在线粒体质量控制中的调节和功能。首先，我们建议 明确VMS1应激反应定位于线粒体的结构和生化基础。这既包括抑制分子内相互作用，也包括VMS1与修饰的鞘磷脂的相互作用。其次，我们建议确定Vms1定位的应激反应的潜在机制，最初的重点是在应激下迁移到线粒体的脂质修饰酶。我们还将证实我们的初步数据表明，这些机制在哺乳动物细胞中起作用。最后，我们将使用细胞培养和小鼠模型相结合的方法来确定Vms1在哺乳动物中的生化和生理功能。这包括鉴定降解底物以及确定缺乏Vms1的小鼠的表型。

 DESCRIPTION (provided by applicant): Progressive mitochondrial damage and the resulting dysfunction are key contributors to many human diseases. Eukaryotic cells have a multi-layered system for damage prevention and response. Many studies in humans and a variety of model systems have implicated mitochondrial protein degradation as one of the first lines of defense. We have uncovered a system, centered on the evolutionarily conserved Vms1 protein, that promotes the removal of proteins from the mitochondrial outer membrane in a stress- responsive manner. We propose an ambitious inter-disciplinary plan to describe the regulation and function of this protein and its associates in mitochondrial quality control. First, we propose to define the structural and biochemical basis for the stress-responsive localization of Vms1 to mitochondria. This involves both an inhibitory intramolecular interaction and the interaction of Vms1 with a modified sphingolipid. Second, we propose to determine the mechanisms underlying the stress-responsiveness of Vms1 localization, with an initial focus on a lipid-modifying enzyme that migrates to mitochondria under stress. We will also confirm our preliminary data suggesting that these mechanisms are operative in mammalian cells. Finally, we will determine the biochemical and physiological function of Vms1 in mammals using a combination of cell culture and mouse models. This includes the identification of degradation substrates as well as defining the phenotype of a mouse lacking Vms1.