The Mechanism of Mitochondrial Fission and Fusion.

描述（由申请人提供）：这是一份竞争性修订申请（通知编号NOT-OD-09-058，通知标题：NIH宣布恢复法案资金可用于竞争性修订申请），其重点是扩大题为“线粒体融合机制”的母基金GM 062942的范围，以涵盖融合DRP，Mgm 1的结构分析。线粒体是动态的，必不可少的，双膜细胞器，在细胞内执行无数的任务。与它们的细菌祖先不同，它们不是离散的实体。分离的线粒体是瞬时的，并且通过融合进行通信，以在细胞内形成局部和广泛的线粒体合胞体。线粒体分裂拮抗融合，这些事件共同作用产生一个连接的隔室，可以进入线粒体DNA，因此具有功能，但能够通过肌动蛋白或微管网络的运输分布到遥远的细胞目的地。我们专注于了解线粒体融合的分子机制，以深入了解融合在细胞和疾病中的作用和调控。除了其基本的细胞作用之外，线粒体融合还调节细胞中的内在凋亡，并且相反地，促凋亡Bcl-2蛋白调节健康细胞中的线粒体融合。线粒体融合是胚胎发育所必需的，融合蛋白的突变导致神经退行性疾病和中风，这一事实强调了融合的重要细胞作用。线粒体融合是独特的，因为它是由高度保守的动力蛋白相关蛋白（DRPs）的作用介导的。DRP是大的GTP酶，其通过其自组装和水解GTP的能力来控制膜重塑事件。我们强大的酵母体外试验揭示了丰富的信息融合机制。我们已经证明，DRPs介导的膜拴系和脂质混合步骤在线粒体外膜和内膜融合。我们最近的工作还表明，非DRP外膜融合蛋白是需要后膜拴系，在外膜和内膜融合的脂质混合步骤。来自Mgm 1结构分析的信息将为内膜融合的分子事件提供新的见解，并指导原始拨款中提出的生化实验。此外，组装Mgm 1的结构分析将提供在DRP家族成员的一般功能，机制和属性的宝贵见解。这笔赠款提供的资金将通过提供一名初级博士后科学家的工资和培训来实现复苏法案的目标。 线粒体在细胞中发挥许多重要作用，包括产生能量。这种关键的线粒体功能和其他功能依赖于线粒体融合，而人类线粒体融合的缺陷会导致神经退行性疾病和中风。

DESCRIPTION (provided by applicant): This is a Competitive Revision Application (notice number NOT-OD-09-058 and Notice Title: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications), which is focused on broadening the scope of the parent grant, GM062942 entitled "Mechanism of Mitochondrial Fusion" to encompass the structural analysis of the fusion DRP, Mgm1. Mitochondria are dynamic, essential, double-membraned organelles that perform a myriad of tasks within cells. Unlike their bacterial ancestors, they are not discrete entities. Isolated mitochondria are transient and in communication via fusion to form both localized and widespread mitochondrial syncytia within cells. Mitochondrial division antagonizes fusion and together these events function to create a compartment that is connected, with access to mtDNA, and thus functional, yet able to be distributed to distant cellular destinations via transport on actin or microtubule networks. We are focused on understanding the molecular mechanism of mitochondrial fusion to gain insight into the roles and regulation of fusion in cells and disease. In addition to its fundamental cellular role, mitochondrial fusion also regulates intrinsic apoptosis in cells and conversely, the pro-apoptotic Bcl-2 proteins regulate mitochondrial fusion in healthy cells. The important cellular roles of fusion are underscored by the fact that mitochondrial fusion is required for embryonic development and mutations in fusion proteins cause neurodegenerative diseases and stroke. Mitochondrial fusion is unique in that it is mediated by the action of highly conserved dynamin-related proteins (DRPs). DRPs are large GTPases that, through their ability to self-assemble and hydrolyze GTP, control membrane remodeling events. Our powerful yeast in vitro assay has revealed a wealth of information regarding the fusion mechanism. We have demonstrated that DRPs mediate both membrane tethering and lipid-mixing steps in fusion at the mitochondrial outer and inner membranes. Our recent work also indicates that a non-DRP outer membrane fusion protein is required post-membrane tethering, at the lipid-mixing step of outer and inner membrane fusion. Information from the structural analysis of Mgm1 will provide novel insight into the molecular events of inner membrane fusion and guide the biochemical experiments proposed in the original grant. In addition, the structural analysis of assembled Mgm1 will provide invaluable insight in the general function, mechanism and properties of DRP family members. The funds provided by this grant will address the goals of the Recovery act by providing for the salary and training of a junior post-doctoral scientist. PUBLIC HEALTH RELEVANCE: Mitochondria perform many important roles in cells, including the production of energy. This critical mitochondrial function and others depend on mitochondrial fusion and defects in mitochondrial fusion in humans cause neurodegenerative diseases and stroke.