Biochemical and genetic analysis of dystonia-Torsin

描述（由申请人提供）：肌张力障碍是一种神经系统症状，其特征为持续的不自主收缩、扭转和转动运动以及姿势。虽然肌张力障碍是许多其他神经系统疾病的症状，但DYT-1肌张力障碍（a.k.a.扭转性肌张力障碍或Oppenheim肌张力障碍）是一种原发性遗传性肌张力障碍。这种常染色体显性遗传疾病是由一种新的内质网（ER）定位蛋白（称为Torsin A）突变引起的，该蛋白是ATP酶AAA家族的成员。扭转蛋白A的功能和致病突变的后果都不清楚。扭转蛋白A在整个神经系统中广泛表达，但也在多种非神经组织中表达。扭蛋白同源物存在于果蝇和C.优雅扭转蛋白与ATP酶的Hspl 00/Clp家族最密切相关，其主要活性是解聚或解折叠错误的蛋白质以用于最终修复或靶向破坏。我们假设，考虑到ER是分泌途径中蛋白质折叠/质量控制的主要位点，扭转蛋白A有助于修复或破坏受损底物。我们有证据表明，torsins可能参与处理未折叠的蛋白质在ER，现在建议进行生化和遗传的方法，并行测试我们的假设。具体来说，我们将对我们生产和纯化的重组torsin A进行结构、功能和酶分析，鉴定ER中的torsin相互作用蛋白，测试torsin是否改变从ER中去除蛋白的动力学，并将进一步研究我们的C。elegans的工作是为了验证我们的假设，并最终开发出一种动物，我们可以在这种动物身上进行正向遗传学研究，以确定torsin途径中的其他基因。我的研究生工作是关于蛋白质进入内质网的机制。在我住院期间，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特定蛋白质错误折叠和积累的突变引起的，但DYT-1肌张力障碍可能是由参与蛋白质折叠的酶改变引起的。我相信，阐明疾病基因的功能最好是通过生物化学和遗传学方法相结合来完成。我希望在蛋白质折叠领域，特别是遗传学领域进一步加强我的科学训练，以便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.