Nascent SOD1 in Amyotrophic Lateral Sclerosis

肌萎缩侧索硬化症中的新生 SOD1

• 批准号: 7791079
• 负责人: Peter JOHN HART
• 金额: --
• 依托单位: SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7791079
• 关键词: 3-Dimensional; Address; Adopted; Affect; Affinity; Age; Aging-Related Process; Amino Acid Substitution; Amino Acids; Amyotrophic Lateral Sclerosis; Antioxidants; Behavior; Binding; Binding Sites; Biochemistry; Cessation of life; Child; Complex; Consultations; Copper; Cultured Cells; DNA Sequence Rearrangement; Data; Defect; Degenerative Disorder; Dimensions; Disease; Dissociation; Disulfides; Enzymes; Event; Exercise; Failure; Familial Amyotrophic Lateral Sclerosis; Family; Future; Gel Chromatography; Generations; Genes; Health Sciences; Hospitals; Human; Inherited; Ions; Iraq; Laboratories; Lead; Lesion; Letters; Light; Link; Measurement; Mediating; Metalloproteins; Metals; Methods; Military Personnel; Modeling; Molecular; Molecular Chaperones; Molecular Conformation; Motion; Motor Neuron Disease; Motor Neurons; Mus; Mutation; Neurodegenerative Disorders; Neurons; Paralysed; Parents; Pathway interactions; Patients; Population; Post-Translational Protein Processing; Process; Proline; Proteins; Relative (related person); Reporting; Resolution; SOD1 gene; Sampling; Site; Solutions; Spinal Cord; Structure; Study Section; Temperature; Testing; Texas; Therapeutic; Therapeutic Agents; Time; Toxic effect; Transgenic Mice; Translating; United States; Universities; Variant; Veterans; War; Work; X ray diffraction analysis; X-Ray Crystallography; X-Ray Diffraction; analytical ultracentrifugation; base; cofactor; conformer; copper zinc superoxide dismutase; design; disease-causing mutation; disulfide bond; gain of function; gel electrophoresis; human tissue; in vivo; interest; melting; molecular mass; mouse model; mutant; oxidation; polypeptide; protein aggregation; protein misfolding; public health relevance; relating to nervous system; research study; sedimentation equilibrium; sedimentation velocity; tool

DESCRIPTION (provided by applicant): Mutations in human copper-zinc superoxide dismutase (SOD1) cause an inherited form of the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease, motor neuron disease). With increasing age, insoluble forms of mutant SOD1 progressively accumulate in neural tissues of human ALS patients and in spinal cords of transgenic mice expressing these polypeptides, suggesting that SOD1- linked ALS is a protein misfolding and aggregation disorder. Understanding the molecular basis for how the pathogenic mutations give rise to SOD1 folding intermediates that are prone to aggregation is therefore of keen interest. A critical step on the folding pathway occurs when the nascent SOD1 polypeptide is posttranslationally modified by the copper chaperone for SOD1 (CCS), a helper protein that inserts the catalytic copper cofactor and oxidizes the SOD1 intrasubunit disulfide bond. CCS recognizes and binds to nascent, but not mature SOD1, suggesting that the newly translated form exists in a conformation distinct from the mature form. Recent studies reveal that pathogenic SOD1 proteins coming from aggregates isolated from cultured cells and from the spinal cords of transgenic mice tend to be metal-deficient and/or lacking the disulfide bond. These observations suggest the hypothesis that the disease-causing mutations may enhance levels of SOD1 folding intermediates by hindering CCS-mediated SOD1 maturation. The experiments outlined in this project are designed to probe the structure and dynamics of nascent SOD1 and to examine its interaction with CCS. Successful completion of the Aims contained herein will address the following questions: 1) What are the structural determinants that are responsible for the recognition of nascent SOD1 by CCS? 2) Is the functional SOD1/CCS complex heterodimeric, heterotetrameric, or some other higher order oligomer? 3) What are the structural details of the nascent SOD1/CCS complex in three dimensions? 4) What factors govern the interconversion of the nascent and mature SOD1 conformations in the absence of CCS? 5) How do the ALS mutations affect the interconversion of the nascent and mature conformations? Answers to these questions are prerequisites for the design of therapeutic agents aimed inhibiting pathogenic SOD1 aggregation in ALS. 1 PUBLIC HEALTH RELEVANCE: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disorder linked to the aging process. Military personnel who served in the first U.S.-Iraq war, have developed sporadic (noninherited) ALS upon their return more frequently than found in the United States population as a whole. Familial ALS (fALS) is passed from parent to child over generations, and the underlying genetic defects were entirely unknown until it was discovered that some ALS families possess mutations in the gene encoding the antioxidant enzyme copper- zinc superoxide dismutase (SOD1). Importantly, the manifestations of sporadic and familial ALS are nearly clinically indistinguishable, suggesting that the underlying molecular causes for the two forms of the disease are related. This proposal investigates SOD1-linked ALS because understanding the molecular basis for motor neuron death in familial cases could lead to therapeutic avenues applicable to sporadic forms of the disease, both of which are expected to increasingly affect the veteran population as it continues to age.

描述（由申请人提供）： 人铜锌超氧化物歧化酶 (SOD1) 的突变会导致遗传性致命的神经退行性疾病肌萎缩侧索硬化症（ALS、卢伽雷氏病、运动神经元病）。随着年龄的增长，不溶性形式的突变体SOD1逐渐在人类ALS患者的神经组织和表达这些多肽的转基因小鼠的脊髓中积累，表明SOD1相关的ALS是一种蛋白质错误折叠和聚集障碍。因此，了解致病性突变如何产生易于聚集的 SOD1 折叠中间体的分子基础引起了人们的浓厚兴趣。当新生的 SOD1 多肽被 SOD1 铜伴侣蛋白 (CCS) 进行翻译后修饰时，折叠途径中的一个关键步骤就会发生。SOD1 铜伴侣蛋白是一种辅助蛋白，插入催化铜辅因子并氧化 SOD1 亚基内二硫键。 CCS 识别并结合新生的 SOD1，但不识别成熟的 SOD1，这表明新翻译的形式以不同于成熟形式的构象存在。最近的研究表明，来自培养细胞和转基因小鼠脊髓中分离的聚集体的致病性 SOD1 蛋白往往缺乏金属和/或缺乏二硫键。这些观察结果表明，致病突变可能通过阻碍 CCS 介导的 SOD1 成熟来提高 SOD1 折叠中间体的水平。该项目中概述的实验旨在探索新生 SOD1 的结构和动力学，并检查其与 CCS 的相互作用。成功完成本文包含的目标将解决以下问题： 1) 导致 CCS 识别新生 SOD1 的结构决定因素是什么？ 2) 功能性 SOD1/CCS 复合物是异二聚体、异四聚体还是其他更高阶的寡聚体？ 3) 新生SOD1/CCS复合体的三维结构细节是什么？ 4) 在没有 CCS 的情况下，哪些因素控制新生和成熟 SOD1 构象的相互转化？ 5）ALS突变如何影响新生构象和成熟构象的相互转换？这些问题的答案是设计旨在抑制 ALS 致病性 SOD1 聚集的治疗药物的先决条件。 1 公共卫生相关性： 肌萎缩侧索硬化症（ALS）是一种与衰老过程相关的进行性神经退行性疾病。参加第一次美伊战争的军事人员在回国后患上散发性（非遗传性）ALS 的频率比美国整体人口中的发病率还要高。家族性 ALS (fALS) 由父母代代相传，在发现某些 ALS 家族编码抗氧化酶铜锌超氧化物歧化酶 (SOD1) 的基因中存在突变之前，其潜在的遗传缺陷完全未知。重要的是，散发性和家族性 ALS 的表现在临床上几乎无法区分，这表明这两种疾病的潜在分子原因是相关的。该提案研究了 SOD1 相关的 ALS，因为了解家族病例中运动神经元死亡的分子基础可能会找到适用于该疾病散发形式的治疗途径，随着退伍军人群体的不断老龄化，预计这两种疾病都会越来越大地影响退伍军人群体。