Aberrant Cardiolipin Dynamics in Barth Syndrome

巴斯综合征中异常的心磷脂动力学

• 批准号: 10385350
• 负责人: Michael Schlame
• 金额: $ 0.55万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10385350
• 关键词: 3-Methylglutaconic aciduria type 2; Address; Affect; Automobile Driving; Cardiolipins; Characteristics; Complex; Crista ampullaris; Crowding; Data; Development; Drosophila genus; Electrons; Energy Metabolism; Enzymes; Fatty Acids; Functional disorder; Germ Cells; Goals; Health; Human; Knowledge; Life; Lipids; Membrane; Metabolic Diseases; Microscopic; Mission; Mitochondria; Mitochondrial Diseases; Mitochondrial Membrane Protein; Molecular; Mus; Mutation; Organelles; Oxidative Phosphorylation; Pathologic; Phospholipids; Proteins; Proteomics; Public Health; Reaction; Role; Spermatogenesis; Stress; System; Techniques; Testing; United States National Institutes of Health; Work; Yeasts; body system; density; disability; experimental study; insight; lipid disorder; lipidome; membrane assembly; mitochondrial membrane; mitochondrial metabolism; stable isotope; tomography

Project Summary/Abstract Mitochondria are membrane-rich organelles that are essential to eukaryotic life. Detailed insight has emerged into the assembly and the dynamics of mitochondrial membrane proteins, but a fundamental gap has remained in understanding mitochondrial lipids. Barth syndrome (BS) is a disorder of the mitochondrial lipid metabolism, in particular the metabolism of the mitochondria-specific phospholipid cardiolipin (CL), and thus provides a unique opportunity to address this gap in a context relevant to human health. BS is caused by mutations in tafazzin, an enzyme that catalyzes CL remodeling, i.e. the fatty acid exchange reaction by which the characteristic molecular composition of CL is created. The objective of this application is to identify mechanism and function of CL remodeling. This objective fits into our broad goals to understand the function of CL in mitochondria and to unravel the molecular pathophysiology of BS. We discovered that the global assembly of the system of oxidative phosphorylation (OXPHOS) is driving CL remodeling. We hypothesize that CL remodeling reduces the packing stress imposed on mitochondrial lipids by the extremely high protein concentration, which arises in mitochondrial membranes due to the OXPHOS system and other proteins. Thus, the function of CL remodeling is to stabilize lipid-protein interactions in order to allow the assembly of protein- crowded membranes. To test this hypothesis, we will (i) identify the mechanism by which OXPHOS expression controls CL remodeling and (ii) establish the function of CL remodeling in membrane assembly. First, in order to identify the mechanism by which OXPHOS expression controls CL remodeling, we will determine the effect of OXPHOS assembly on the CL remodeling reaction, then identify the OXPHOS assembly step that is critical for CL remodeling, and finally determine whether protein crowding affects CL remodeling. Second, in order to establish the function of CL remodeling, we will determine the effect of CL remodeling on the density of OXPHOS complexes, on the stability of cristae membranes, and on the development of germ cell mitochondria. Germ cell mitochondria will be studied because our preliminary data suggest a specific role of CL remodeling and OXPHOS assembly in spermatogenesis. Experiments will be carried out in genetically modified yeast, Drosophila, and mice. Our application relies on cutting-edge techniques, such as lipidome- wide flux analysis with stable isotopes, cryo-electron microscopic tomography, and quantitative proteomics. The proposed study is significant because it will identify the mechanism and the function of CL remodeling, a widely conserved reaction of uncertain significance, and because it will establish the pathologic mechanism of BS.

项目概要/摘要 线粒体是富含膜的细胞器，对真核生命至关重要。详细的见解已经出现 线粒体膜蛋白的组装和动力学，但仍然存在根本差距 了解线粒体脂质。巴特综合征（BS）是一种线粒体脂质代谢紊乱， 特别是线粒体特异性磷脂心磷脂（CL）的代谢，从而提供了 在与人类健康相关的背景下解决这一差距的独特机会。 BS 是由突变引起的 tafazzin，一种催化 CL 重塑的酶，即脂肪酸交换反应，通过该反应， 创建了 CL 的特征分子组成。该应用程序的目的是识别 CL重构的机制和功能。这个目标符合我们理解功能的广泛目标 线粒体中的 CL 并揭示 BS 的分子病理生理学。我们发现全球 氧化磷酸化系统 (OXPHOS) 的组装正在驱动 CL 重塑。我们假设 CL 重塑减少了极高蛋白质对线粒体脂质施加的堆积压力 浓度，由于 OXPHOS 系统和其他蛋白质而在线粒体膜中产生。因此， CL 重塑的功能是稳定脂质-蛋白质相互作用，以允许蛋白质-蛋白质的组装。 拥挤的膜。为了检验这一假设，我们将 (i) 确定 OXPHOS 表达的机制 控制 CL 重塑并 (ii) 建立 CL 重塑在膜组装中的功能。首先，按顺序 为了确定 OXPHOS 表达控制 CL 重塑的机制，我们将确定其效果 OXPHOS 组装对 CL 重塑反应的影响，然后确定关键的 OXPHOS 组装步骤 进行CL重构，最终确定蛋白质拥挤是否影响CL重构。其次，为了 建立CL重构函数，我们将确定CL重构对密度的影响 OXPHOS 复合物对嵴膜稳定性和生殖细胞发育的影响 线粒体。将研究生殖细胞线粒体，因为我们的初步数据表明， 精子发生中的 CL 重塑和 OXPHOS 组装。实验将在基因方面进行 改良酵母、果蝇和小鼠。我们的应用依赖于尖端技术，例如脂质组学 稳定同位素的宽通量分析、冷冻电子显微镜断层扫描和定量蛋白质组学。 这项研究意义重大，因为它将确定 CL 重塑的机制和功能，这是一种 意义不确定的广泛保守的反应，并且因为它将建立病理机制 BS。