Mitochondria, apoptosis and the Bcl-2 family

线粒体、细胞凋亡和 Bcl-2 家族

• 批准号: 7123844
• 负责人: DONALD DAVID NEWMEYER
• 金额: $ 37.07万
• 依托单位: LA JOLLA INSTITUTE FOR IMMUNOLOGY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7123844
• 关键词: BCL2 gene /protein; Bax gene /protein; Xenopus oocyte; apoptosis; biological signal transduction; cysteine endopeptidases; cytochrome c; enzyme activity; gene expression; genetically modified animals; laboratory mouse; laboratory rat; membrane permeability; mitochondria; mitochondrial membrane; protein protein interaction

DESCRIPTION (provided by applicant): Bcl-2-family proteins play a key role in the control of apoptosis. In particular, gene targeting studies in mice have shown that Bax and Bak (and by analogy, perhaps Bok) are critical effectors; in the absence of these proteins, cells show deficiencies in many forms of apoptosis. Our focus is on how these Bcl-2-family proteins regulate mitochondrial outer membrane permeabilization (MOMP), a primary event in many cell death pathways. MOMP leads to the translocation of cytochrome c and other apoptotic trigger proteins from the mitochondria! inner membrane space into the cytoplasm; these proteins in turn regulate caspase activation and the execution phase of apoptosis. However, even if caspases are inactive or absent, MOMP nevertheless appears to doom most cells to die, through initiating a loss of key mitochondrial functions as well as the generation of reactive oxygen species. Thus, the regulation and mechanism of this process are of critical importance. Here we propose studies that will help elucidate the roles of Bcl-2-family proteins in MOMP. We will use both cell-free systems, to tease apart the mechanisms of action of these proteins, and whole-cell and in vivo approaches, which will extend these investigations to a more physiological context. There are three principal subgroups of the Bcl-2 family: "BH1-4" proteins, which are anti-apoptotic; "BH1-3" proteins, which include the pro-apoptotic family members Bax, Bak and Bok, and the "BH3-only" proteins, which are also pro-apoptotic. The BH3-only proteins are more numerous, are activated specifically through transcriptional and post-translational mechanisms in the context of different cellular stresses, and appear to regulate the other two subfamilies. Our aims, which address each category of the Bcl-2 family in turn, are first, to explore the mechanisms through which the BH3-only proteins regulate the activation of Bax-type proteins; second, to investigate the mechanism of membrane permeabilization by Bax-type proteins; and third, to understand how Bcl-xL, a member of the BH1-4 category, can both prevent MOMP and also reseal the MOM after MOMP has occurred.

描述（由申请人提供）：BCL-2-家庭蛋白在控制凋亡中起关键作用。特别是，小鼠的基因靶向研究表明，Bax和Bak（以及类比，也许是Bok）是关键效应子。在没有这些蛋白质的情况下，细胞在多种形式的凋亡中表现出缺陷。我们的重点是这些BCL-2家庭蛋白如何调节线粒体外膜通透性（MOMP），这是许多细胞死亡途径中的主要事件。 MOMP导致细胞色素C和线粒体中其他凋亡触发蛋白的易位！内膜空间进入细胞质；这些蛋白质反过来调节caspase激活和凋亡的执行阶段。但是，即使胱天蛋白酶不活跃或不存在，MOMP仍然通过启动关键的线粒体功能以及产生活性氧物质的丧失，使大多数细胞死亡。因此，此过程的调节和机制至关重要。在这里，我们提出的研究将有助于阐明Bcl-2家族蛋白在MOMP中的作用。我们将使用两个无细胞系统，嘲笑这些蛋白质的作用机理，以及整个细胞和体内方法，这将把这些研究扩展到更加生理的环境。 Bcl-2家族的三个主要亚组：“ BH1-4”蛋白质，它们是抗凋亡的； “ BH1-3”蛋白质包括促凋亡的家庭成员Bax，Bak和Bok和“仅BH3”蛋白，它们也是促凋亡的。在不同的细胞应激的背景下，仅通过转录和翻译后机制专门激活了仅BH3的蛋白质，并且似乎调节了其他两个亚家族。我们的目标依次依次解决Bcl-2家族的每个类别，首先是探索仅BH3蛋白调节Bax-type蛋白激活的机制；其次，研究巴克斯型蛋白质膜通透性的机理；第三，要了解BH1-4类别的成员BCL-XL如何防止MOMP并在MOMP发生后重新密封妈妈。