Role of Parkin in Familial and Idiopathic Parkinson's Disease

描述(申请人提供)：帕金森病(PD)是一种进行性神经退行性疾病，其特征是黑质神经元近乎选择性的丧失。虽然疾病的病因尚不清楚，但导致家族性帕金森病的基因突变很可能为特发性疾病的潜在机制提供关键的分子线索。泛素E3连接酶PARKIN功能缺失突变是常染色体隐性遗传性帕金森病最常见的原因。Parkin现在被广泛认为是一种支持生存的蛋白，在细胞损伤过程中迅速上调。Parkin被认为对线粒体生物学具有广泛的影响，可能与特发性帕金森病有关。然而，这些效应的生化底物在很大程度上是未知的。我们工作的长期目标是揭示帕金森对线粒体的影响的分子机制。这些信息不仅将提高我们对一个重要的神经元应激反应蛋白的理解，还将阐明可能参与帕金森病选择性神经变性的新的生化途径。这一应用的实验重点是研究由Parkin神经元缺陷引起的线粒体缺陷，并确定相关蛋白质。有三个具体目标。1)分析参与线粒体分裂和凋亡的两种新的Parkin底物的Parkin依赖泛素化。我们将确定内源性parkin对蛋白质半衰期和定位的影响，以及这些候选底物对parkin缺陷神经元线粒体缺陷的贡献。2)分析原代培养神经元Parkin缺失对线粒体的影响，并检测Parkin缺失神经元对特发性帕金森病相关应激源的易感性增强。3)研究发生在Parkin缺陷神经元中的蛋白质运输和功能的线粒体特异性变化。这些研究的完成将建立PARKIN的E3连接酶活性与其作为具有线粒体影响的促生存应激反应蛋白的功能之间的机制联系。这项工作将阐明参与帕金森病发病机制的新的生化途径，并可能发现治疗干预的创新靶点。 公共卫生相关性：帕金森与保护性神经元应激反应密切相关，与家族性帕金森氏症有因果关系。这项研究的目的是了解parkin维持线粒体完整性的确切机制，并确定可能导致帕金森氏症的分子事件。这些通路一旦被发现，可能会为这种毁灭性的神经疾病的治疗确定新的治疗目标。

DESCRIPTION (provided by applicant): Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the near selective loss of neurons in the substantia nigra. While the etiology of the disease is unknown, genetic mutations responsible for familial forms of PD will likely provide critical molecular clues to the underlying mechanisms of idiopathic disease. Loss-of-function mutations in the ubiquitin E3 ligase parkin are the most common cause of autosomal recessive PD. Parkin is now widely recognized as a pro-survival protein rapidly up-regulated during cell injury. Parkin is believed to possess broad ranging effects on mitochondrial biology that are likely relevant to idiopathic PD. However, the biochemical substrates of these effects are largely unknown. The long-term goal of our work is to uncover the molecular machinery responsible for parkin's influence on mitochondria. This information will not only improve our understanding of an important neuronal stress response protein but will also elucidate new biochemical pathways likely involved in the selective neurodegeneration in PD. The experimental focus of this application is on the mitochondrial defects that result from neuronal deficiencies in parkin and identifying the proteins responsible. There are three specific aims. 1) Analyze the parkin-dependent ubiquitination of two novel parkin substrates involved in mitochondrial fission and apoptosis. We will determine the effects of endogenous parkin on protein half-life and localization, and the contribution of these candidate substrates on mitochondrial defects in parkin deficient neurons. 2) Analyze the mitochondrial consequences of parkin deficiency in primary cultured neurons, and examine enhanced vulnerabilities of parkin null neurons to stressors implicated in idiopathic PD. 3) Examine mitochondria-specific changes in protein trafficking and function that occur in parkin deficient neurons. The completion of these studies will establish mechanistic links between the E3 ligase activity of parkin and its function as a pro-survival stress response protein with mitochondrial influence. This work will elucidate novel biochemical pathways involved in the pathogenesis of PD and potentially uncover innovative targets for therapeutic intervention. PUBLIC HEALTH RELEVANCE: Parkin is critically involved in a protective neuronal stress response and is causally linked to familial Parkinson's disease. The goal of this study is to understand the precise mechanisms by which parkin maintains integrity of the mitochondria and to define molecular events that can cause Parkinson's disease. These pathways, once discovered, may identify new therapeutic targets for the treatment of this devastating neurological disorder.