PHOSPHOLIPIDS AND MITOCHONDRIAL FUNCTION

磷脂和线粒体功能

• 批准号: 6019344
• 负责人: WILLIAM DOWHAN
• 金额: $ 26.27万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6019344
• 关键词: Saccharomyces cerevisiae; cardiolipins; enzyme mechanism; gene deletion mutation; gene expression; genetic regulation; genetic transcription; genetic translation; mitochondria; molecular biology; phospholipids; protein biosynthesis; protein purification

DESCRIPTION: (adapted from applicant's abstract) Significant reduction of mitochondrial cardiolipin (CL) has been postulated to compromise directly cytochrome oxidase function, the ADP/ATP translocator, phosphate translocator, ATP synthase, palmitoyl carnitine transferase, and carnitine translocase. Inhibition of any of these processes would lead to mitochondrial dysfunction particularly in the process of oxidative phosphorylation. Compromising terminal oxidation has been shown to accentuate both short term and long term oxidative damage to tissue because of the build up of highly reactive intermediates generated by the electron transport chain leading to even further damage. With aging the cholesterol to phospholipid ratio of heart muscle mitochondrial increases due to loss of CL which has been associated with increases in membrane rigidity. To date there is no genetic evidence for any of the critical roles with which CL has been associated, and the lack of mutants in the synthesis of CL in eukaryotic cells has made it difficult to reconcile in vitro observations of the role of CL with in vivo processes. We have isolated the genes (PGSI and CLS1) from Saccharomyces cerevisiae that encode the phosphatidylglycerol-(PG) phosphate (P) and CL synthases, which are responsible for the synthesis of CL in mitochondria. By making mutants null in the these genes, the requirement for PG/CL for both cell viability and mitochondrial function will be established. Using these null mutants and strains in which the expression of these genes are artificially regulated, the cellular processes dependent on PG and/or CL will be identified and their requirement for these lipids will be detailed at the molecular level. Since CL appears to be a critical for phospholipid to mitochondrial function, understanding the regulation of its synthesis is important to a better understanding of the relationship between variation in CL levels and cellular dysfunction. The regulation at the level of transcription and translation of these genes will be investigated to gain insight into CL homeostasis. Additional insight into CL regulation will be obtained by purifying and characterizing the enzymological properties of the PG-P synthase, which is the rate limiting enzyme in CL synthesis, as well as the CL synthase, the terminal step in CL synthesis. Given the complexity of molecular genetic and biochemical studies in somatic cells and the similarity of apparent CL function in all eukaryotic cells, the detailed studies of CL synthesis and function in yeast will lead to a clearer understanding of the function of this phospholipid in all eukaryotic cells.

描述：（改编自申请人的摘要）显着减少 线粒体心脂蛋白（CL）的假设已妥协 直接的细胞色素氧化酶功能，ADP/ATP转运剂， 磷酸盐转运剂，ATP合酶，棕榈酰carnitine转移酶， 和肉碱易位酶。 抑制这些过程中的任何一个都将 导致线粒体功能障碍，特别是在 氧化磷酸化。 妥协的末端氧化已经是 显示出可突出短期和长期氧化损伤 由于高度反应性中间体的积累而组织 由电子传输链生成 损害。 随着心脏的胆固醇与磷脂比的老化 肌肉线粒体因CL的损失而增加 与膜刚度的增加有关。 迄今为止没有 CL所使用的任何关键作用的遗传证据 相关，以及在真核的合成中缺乏突变体 细胞使得很难在体外观察到 CL具有体内过程的作用。 我们已经隔离了基因（PGSI和 Cls1）来自酿酒酵母的cls1） 磷脂酰甘油（Pg）磷酸（P）和Cl合酶，它们是 负责线粒体中CL的合成。 通过制作突变体 这些基因中的无效，对两个细胞的PG/Cl的需求 将建立生存能力和线粒体功能。 使用这些 这些基因表达的无效突变体和菌株是 人为调节的细胞过程取决于PG和/或 CL将被确定，它们对这些脂质的要求将是 在分子水平上详细介绍。 因为CL似乎对 磷脂至线粒体功能，了解 它的综合对于更好地理解关系很重要 在CL水平的变化和细胞功能障碍之间。 法规 这些基因的转录和翻译水平将是 调查以了解CL稳态。 其他见解 通过净化和表征CL调节 PG-P合酶的酶学特性，这是速率 限制Cl合成中的酶以及Cl合酶， Cl合成中的末端步骤。 鉴于分子的复杂性 体细胞中的遗传和生化研究以及 在所有真核细胞中的明显CL功能，详细研究 酵母中CL合成和功能将导致更清晰的理解 该磷脂在所有真核细胞中的功能。