Mechanisms of Mitochondrial Fission

描述（由申请人提供）：线粒体是动态细胞器，其形态和功能通过对抗分裂和融合来调节。利用这笔赠款提供的资金，我的实验室证明了一种名为Dnm 1的动力蛋白相关的GTdR控制着芽殖酵母中的线粒体裂变。Dnm 1定义了一个保守的线粒体GTP酶家族，在细胞生理学和人类健康中具有重要但知之甚少的功能。 酵母Dnm 1的人类同源物被称为Drp 1。在哺乳动物和细胞系中进行的研究表明，Drp 1在维持线粒体功能、细胞凋亡过程中的线粒体片段化以及自噬线粒体片段的产生中起着关键作用。基于这些发现，调节线粒体分裂的分子是抑制性药物的潜在靶点，这些抑制性药物减少线粒体碎片化和不必要的细胞死亡，包括中风后心脏细胞的凋亡或与各种神经病变相关的神经元细胞死亡。 这个建议集中在芽殖酵母的裂变机制上，芽殖酵母是所有真核生物（包括人类）线粒体裂变机制的原型。这个领域已经成熟到这样一个阶段：主要问题集中在Dnm 1及其结合伙伴如何在适当的空间和时间控制下共同工作以引发裂变。为了超越这一阶段，关键是要更好地了解Dnm 1裂变复合物的组分如何相互作用和组装，以及这些相互作用如何影响裂变活性。这里描述的研究旨在获得这种机制和结构信息。有了这些知识，我们将生成和测试Dnm 1组装和裂变复合物活性调节的特定模型。 公共卫生相关性：拟议的研究将推进机制和结构的理解，调节线粒体分裂的分子使用酵母作为模型系统。这种核心线粒体分裂机制包括Dnm 1 GTf 3、Mdv 1/Caf 4衔接子和Fis 1膜锚。这些结果将与人类发育和健康相关，因为这些蛋白质具有人类同源物，包括人类Drp 1（酵母Dnm 1同源物）及其膜受体人类Fis 1（酵母Fis 1同源物）。人Drp 1在维持线粒体功能、细胞凋亡过程中的线粒体片段化以及自噬线粒体片段的产生中起着关键作用。Drp 1基因的突变与一名婴儿出生后37天的死亡有关。本申请中的实验利用酵母中可用的复杂工具来探测裂变复合物组装和活性的机制。从这些研究中所学到的将使科学家和临床医生能够操纵这些分子的活动，以造福人类健康

DESCRIPTION (provided by applicant): Mitochondria are dynamic organelles whose morphology and function are regulated by opposing fission and fusion. Using funds provided by this grant, my laboratory demonstrated that a dynamin-related GTPase called Dnm1 controls mitochondrial fission in budding yeast. Dnm1 defines a conserved family of mitochondrial GTPases with important but poorly understood functions in cell physiology and human health. The human homolog of yeast Dnm1 is called Drp1. Studies performed in mammals and cell lines suggest that Drp1 plays critical roles in maintaining mitochondrial function, mitochondrial fragmentation during apoptosis, and generation of mitochondrial fragments for autophagy. Based on these findings, molecules that regulate mitochondrial fission are potential targets for inhibitory drugs that reduce mitochondrial fragmentation and unwanted cell death, including the apoptotic death of cardiac cells after stroke or the neuronal cell death associated with a variety of neuropathies. This proposal focuses on the fission machinery of budding yeast, which serves as the prototype for mitochondrial fission machineries in all eukaryotes, including humans. This field has matured to the stage where the major questions are focused on how Dnm1 and its binding partners work together to elicit fission with the proper spatial and temporal control. To progress beyond this stage, it is critical to obtain a better mechanistic and structural understanding of how components of the Dnm1 fission complex interact and assemble, and how these interactions affect fission activity. The studies described here are designed to obtain this mechanistic and structural information. With this knowledge in hand, we will generate and test specific models for the regulation of Dnm1 assembly and fission complex activity. PUBLIC HEALTH RELEVANCE: The proposed studies will advance mechanistic and structural understanding of the molecules that regulate mitochondrial fission using yeast as a model system. This core mitochondrial fission machinery includes the Dnm1 GTPase, Mdv1/Caf4 adaptors, and the Fis1 membrane anchor. The results will be relevant to human development and health, as these proteins have human homologs including human Drp1 (yeast Dnm1 homolog) and its membrane receptor human Fis1 (yeast Fis1 homolog). Human Drp1 plays critical roles in maintaining mitochondrial function, mitochondrial fragmentation during apoptosis, and generation of mitochondrial fragments for autophagy. A mutation in Drp1 was recently linked to the death of an infant 37 days after birth. Experiments in this application take advantage of the sophisticated tools available in yeast to probe the mechanism of fission complex assembly and activity. What is learned from these studies will allow scientists and clinicians to manipulate the activities of these molecules for the benefit of human health