Integrative Structural and Functional Characterization of Tip-Link Cadherins Deafness

Tip-Link 钙粘蛋白耳聋的综合结构和功能表征

• 批准号: 9502717
• 负责人: Ulrich Mueller
• 金额: $ 71.62万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-15 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9502717
• 关键词: Adhesions; Affect; Age; Attention; Auditory; Bacteria; Binding; Biochemical; Biophysics; CDH23 gene; Cadherin Domain; Cadherins; Cell physiology; Cells; Child; Cochlea; Complex; Crystallography; Data; Defect; Development; Dimerization; Disease; Disease Outcome; Dissection; Extracellular Domain; Gene Mutation; Genes; Genetic Polymorphism; Genetically Engineered Mouse; Goals; Hair; Hair Cells; Health; Hearing; Hearing Tests; Image; Imaging Device; Impairment; Inner Hair Cells; Investigation; Ion Channel; Laboratories; Labyrinth; Lead; Link; Mammalian Cell; Maps; Mechanics; Mediating; Membrane; Molecular; Morphogenesis; Mus; Mutation; Neurosciences; Noise; Noise-Induced Hearing Loss; PCDH15 gene; Pathogenesis; Physiological; Presbycusis; Property; Publishing; Resolution; Retinal; Role; Signal Transduction; Structure; Structure-Activity Relationship; Surface; Syndrome; Testing; Usher Syndrome; Visual; X-Ray Crystallography; age related; aging population; base; biochemical tools; biophysical analysis; congenital deafness; deafness; dimer; early onset; extracellular; hearing impairment; insight; intermolecular interaction; link protein; loss of function mutation; mechanotransduction; member; mutant; neurotransmission; particle; protein complex; protein structure; reconstruction; sound; vibration

Deafness is a major health problem. A major cause of deafness is defects in hair cells, the mechanosensory cells of the cochlea that convert sound induced vibrations into electrical signals to provide our sense of hearing. Mutations in the genes encoding protocadherin (PCDH15) and cadherin 23 (CDH23) cause hearing loss. Both genes are expressed in the hair bundles of the mechanosensory hair cells of the inner ear where they form heterophilic adhesion complexes that are important for hair bundle morphogenesis and mechanotransduction. Significantly, different mutation in both PCDH15 and CDH23 lead to different disease outcomes. While some mutations cause profound congenital deafness with retinal impairment (Usher Syndrome) others lead to recessive and progressive hearing loss without visual involvement. Gene-association studies also suggest a link of CDH23 polymorphisms with age- and noise-induce hearing loss. The mechanisms by which different mutations lead to distinct disease outcomes are poorly defined. We propose here to combine high-resolution structural studies with functional studies in hair cells to gain insights into the mechanisms by which PCDH15 and CDH23 regulate hair cell function and to define disease mechanisms. To achieve this goal, a laboratory with expertise in studying the biophysical and structural properties of cadherins and a laboratory dedicated to the study of auditory neuroscience have combined their efforts to achieve what either could not accomplish alone. Unlike previous studies that have focused on structural analysis of small monomeric fragments of CDH23 and PCDH15 expressed in bacteria, the team proposed to define the high- resolution structure of natively assembled PCDH15-CDH23 complexes using crystallography and cryo-EM. Structural data will be validated biochemically and by functional interrogation of mutant cadherins in the physiologically relevant mechanosensory hair cells paying attention to mutations associated with disease. We anticipate that our studies will provide the first high-resolution native structure of any protein complex important for mechanotransduction and provide mechanistic insights into its functional properties and pathophysiological mechanisms that are associated with different forms of hearing impairment.

耳聋是一个主要的健康问题。耳聋的一个主要原因是毛细胞（机械感觉细胞）的缺陷 耳蜗细胞将声音引起的振动转化为电信号，以提供我们的感觉 听力。编码原钙粘蛋白 (PCDH15) 和钙粘蛋白 23 (CDH23) 的基因突变会导致听力下降 损失。这两个基因均在内耳机械感觉毛细胞的发束中表达，其中 它们形成对发束形态发生很重要的异嗜性粘附复合物 力传导。值得注意的是，PCDH15和CDH23的不同突变会导致不同的疾病 结果。虽然一些突变会导致严重的先天性耳聋和视网膜损伤（Usher 综合症）其他导致隐性和进行性听力损失，但不涉及视力。基因关联 研究还表明 CDH23 多态性与年龄和噪音引起的听力损失有关。这 不同突变导致不同疾病结果的机制尚不清楚。我们建议 在这里将毛细胞的高分辨率结构研究与功能研究结合起来，以深入了解毛细胞 PCDH15 和 CDH23 调节毛细胞功能的机制并确定疾病机制。到 为了实现这一目标，我们建立了一个专门研究钙粘蛋白生物物理和结构特性的实验室 和一个致力于听觉神经科学研究的实验室共同努力，以实现以下目标： 任何一个都无法单独完成。与之前的研究不同，这些研究侧重于小型结构分析 为了确定细菌中表达的 CDH23 和 PCDH15 的单体片段，研究小组提出定义高 使用晶体学和冷冻电镜解析天然组装的 PCDH15-CDH23 复合物的结构。 结构数据将通过生化和突变钙粘蛋白的功能询问进行验证 生理相关的机械感觉毛细胞关注与疾病相关的突变。我们 预计我们的研究将提供任何重要蛋白质复合物的第一个高分辨率天然结构 用于机械转导并提供对其功能特性和病理生理学的机制见解 与不同形式的听力障碍相关的机制。