Biochemical and genetic analysis of dystonia-Torsin

描述(申请人提供)：肌张力障碍是一种神经系统症状，特征是持续的非自愿收缩，扭转和转身动作，以及姿势。虽然肌张力障碍是许多其他神经疾病的症状，但Dyt-1肌张力障碍(又名扭转肌张力障碍或奥本海姆肌张力障碍)是一种原发遗传性肌张力障碍。这种常染色体显性遗传病是由一种新的内质网(ER)定位蛋白Torsin A的突变引起的，Torsin A是ATPase的AAA家族成员之一。既不知道Torsin A的功能，也不知道致病突变的后果(S)。Torsin A在神经系统中广泛表达，但也在许多非神经组织中表达。果蝇和线虫中存在Torsin同源物。Torsins与Hpl00/CIP家族的ATPase关系最密切，其主要功能是解聚或解开错误折叠的蛋白质，以供最终修复或靶向破坏。我们假设，鉴于内质网是分泌途径中蛋白质折叠/质量控制的主要部位，Torsin A帮助修复或分解受损底物。我们有证据表明Torsins可能参与处理内质网中未折叠的蛋白质，现在建议同时采用生化和遗传方法来验证我们的假设。具体地说，我们将对我们生产和纯化的重组Torsin A进行结构、功能和酶学分析，鉴定ER中Torsin相互作用的蛋白质，测试Torsin是否改变了从ER中去除蛋白质的动力学，并将进一步我们的线虫工作，以验证我们的假设，并最终发展一种动物，在其中我们可以执行正向遗传学来识别Torsin途径中的其他基因。我的研究生工作是关于蛋白质被输入内质网的机制。在我实习期间，我对神经退行性疾病中的蛋白质折叠产生了兴趣。虽然许多神经系统疾病是由导致错误折叠和特定蛋白质堆积的突变引起的，但Dyt-1肌张力障碍可能是由参与蛋白质折叠的一种改变的酶引起的。我认为阐明疾病基因的功能最好是通过生化和遗传学相结合的方法来完成。我希望进一步加强我在蛋白质折叠领域的科学培训，特别是遗传学方面的培训，这样我就可以扩大我们的研究范围。

DESCRIPTION (provided by applicant): Dystonia is a neurologic symptom characterized by sustained involuntary contractions, twisting and turning motions, and postures. While dystonia is a symptom of many other neurologic disorders, DYT-1 dystonia (a.k.a. Torsion Dystonia or Oppenheim's Dystonia) is a primary genetic dystonia. This autosomal dominant disorder is caused by a mutation in a novel Endoplasmic Reticulum (ER)-Iocalized protein named Torsin A that is a member of the AAA family of ATPases. Neither the function of Torsin A nor the consequence(s) of the disease-causing mutation is known. Torsin A is expressed widely throughout the nervous system, but is also expressed in a large variety of non-neural tissues as well. Torsin homologues exist in Drosophila and in C. elegans. The Torsins are most closely related to the Hspl00/CIp family of ATPases whose principal activity is to disaggregate or unfold misfolded proteins for eventual repair or for targeted destruction. We hypothesize that, given that the ER is the major site of protein folding/quality control in the secretory pathway, Torsin A assists in the repair or catabolism of damaged substrates. We have evidence that torsins may be involved in handling unfolded proteins in the ER and now propose to undertake biochemical and genetic approaches in parallel to test our hypothesis. Specifically, we will perform structural, functional, and enzymatic analyses of recombinant torsin A that we produced and purified, identify torsin interacting proteins in the ER, test whether torsin alters the kinetic of removal of proteins from the ER, and will further our C. elegans work both to test our hypothesis and to eventually develop an animal in which we can perform forward genetics to identify other genes in the torsin pathway. My graduate work concerned the mechanism by which proteins are imported into the endoplasmic reticulum. During my residency I developed an interest in protein folding in neurodegenerative disorders. Whereas many neurologic illnesses are caused by mutations that result in mis-folding and accumulation of specific proteins, DYT-1 dystonia may result from an altered enzyme involved in protein folding. I believe that elucidating the function of disease genes is best accomplished by combined biochemical and genetic approaches. I hope to further my scientific training in both the field of protein folding and more particularly in genetics so that I can expand the scope of our investigations.