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，其特征是持续的不自主收缩、扭转和旋转运动和姿势。虽然肌张力障碍是许多其他神经系统疾病的症状，但DYT-1型肌张力障碍（又称扭转肌张力障碍或奥本海姆肌张力障碍）是一种原发性遗传性肌张力障碍。这种常染色体显性疾病是由一种名为Torsin a的新型内质网（ER）局部蛋白突变引起的，该蛋白是atp酶AAA家族的成员。Torsin A的功能和致病突变的后果都是未知的。Torsin 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。在果蝇和秀丽隐杆线虫中存在梭蛋白同源物。torsin与Hspl00/CIp ATPases家族最密切相关，其主要活性是分解或展开错误折叠的蛋白质以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有助于受损底物的修复或分解代谢。我们有证据表明，肌浆蛋白可能参与处理内质网中未折叠的蛋白质，现在我们建议同时采用生化和遗传方法来验证我们的假设。具体来说，我们将对我们生产和纯化的重组肌体蛋白A进行结构、功能和酶分析，鉴定内质网中肌体蛋白的相互作用蛋白，测试肌体蛋白是否会改变内质网中蛋白质去除的动力学，并将进一步我们的秀丽隐杆线虫研究，以验证我们的假设，并最终开发出一种动物，我们可以在这种动物身上进行前向遗传学，以鉴定肌体蛋白途径中的其他基因。我的研究生工作是研究蛋白质进入内质网的机制。在实习期间，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方法的结合来完成的。我希望在蛋白质折叠领域，特别是在遗传学领域，进一步加强我的科学训练，这样我就可以扩大我们研究的范围。

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.