Nanomechanics of Inner Ear Hair Cell Transduction

内耳毛细胞转导的纳米力学

• 批准号: 9889926
• 负责人: Marcos Sotomayor
• 金额: $ 32.73万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9889926
• 关键词: Affinity; Animal Model; Behavior; Binding; Binding Sites; Biochemical; Biological Assay; Biophysics; Blindness; Brain; CDH23 gene; Cadherins; Calcium; Calcium Binding; Calcium ion; Cell physiology; Cochlea; Computer Models; Development; Elasticity; Elements; Equilibrium; Exposure to; Extracellular Domain; Filament; Fishes; Goals; Hair; Hair Cells; Head Movements; Hearing; Human; Ion Channel; Ions; Labyrinth; Life; Light; Link; Mechanics; Mechanoreceptors; Mediating; Methods; Missense Mutation; Modeling; Molecular; Mus; Mutation; Natural regeneration; Noise; PCDH15 gene; Perception; Phenotype; Physiological; Process; Property; Protein Isoforms; Proteins; Sensory; Severities; Shapes; Signal Transduction; Site; Spectrum Analysis; Stimulus; Structural Models; Structure; Usher Syndrome; Variant; Work; X-Ray Crystallography; biophysical properties; biophysical techniques; cellular transduction; deafness; equilibration disorder; experimental study; extracellular; genetic deafness; hearing impairment; human model; insight; lateral line; link protein; nanomechanics; normal hearing; novel; progressive hearing loss; public health relevance; sound; treatment strategy; vibration

 DESCRIPTION (provided by applicant): Inner ear hair cells mediate our senses of hearing and balance by transforming mechanical stimuli from sound and head movements into electrochemical signals that can be processed by the brain. At the core of hair cell function are "tip links", fine protein filaments essential for normal hearing and that are involved in inherited deafness. Two enormous cadherin proteins have been shown to form the mature tip link (cadherin-23 and protocadherin-15), which is thought to be a straight filament with tightly, bound calcium ions that give it rigidity and strength. Transient, immature protocadherin-15 tip link variants have been suggested to be important during development and tip link regeneration after noise-induced damage. There might be additional physiologically relevant variants formed by multiple isoforms of cadherin-23 and protocadherin-15. The overall goal of this project is to determine the biophysical and biochemical behavior of tip links when exposed to different calcium concentrations, when made by different protein variants, and when they carry deafness-related mutations. In aim 1, force spectroscopy and various biophysical and biochemical methods will be used to determine how changing calcium concentration modifies tip link properties and how non-canonical calcium binding sites of protocadherin-15 alter its elasticity. In aim 2, x-ray crystallography and computational modeling will be used to obtain and characterize models of tip link variants involving all extracellular isoforms of cadherin-23 and protocadherin-15. In aim 3, various methods will be used to determine the biochemical and biophysical consequences of missense mutations and deletions associated with inherited deafness, both to explain the severity of observed phenotypes and to predict the effects of yet to be found mutations and deletions in tip link proteins. Results of this project will provide a clear molecula view of tip link properties and function under various physiologically relevant circumstances, and may inform treatment strategies and molecular therapies for inherited deafness.

 描述（由申请人提供）：内耳毛细胞通过将来自声音和头部运动的机械刺激转化为可由大脑处理的电化学信号来调节我们的听觉和平衡感。毛细胞功能的核心是“尖端连接”，这是正常听力所必需的细蛋白丝， 耳聋两个巨大的钙粘蛋白蛋白质已被证明形成成熟的尖端连接（钙粘蛋白-23和15），这被认为是一个直丝与紧密结合的钙离子，使其刚性和强度。短暂的，不成熟的原钙粘蛋白-15尖端连接变体已被认为是重要的，在发展和尖端连接再生后，噪音诱导的损害。可能存在由钙粘蛋白-23和原钙粘蛋白-15的多种亚型形成的其他生理相关变体。该项目的总体目标是确定当暴露于不同的钙浓度时，当由不同的蛋白质变体制成时，以及当它们携带与遗传相关的突变时，尖端链接的生物物理和生物化学行为。在目标1中，力谱和各种生物物理学和生物化学方法将用于确定改变钙浓度如何改变尖端连接特性以及原钙粘蛋白-15的非经典钙结合位点如何改变其弹性。在 目标2：X射线晶体学和计算建模将用于获得和表征涉及钙粘蛋白-23和原钙粘蛋白-15的所有细胞外同种型的尖端连接变体的模型。在目标3中，将使用各种方法来确定与遗传性耳聋相关的错义突变和缺失的生物化学和生物物理学后果，以解释观察到的表型的严重程度，并预测尚未发现的尖端连接蛋白突变和缺失的影响。该项目的结果将提供在各种生理相关情况下尖端连接特性和功能的清晰分子视图，并可能为遗传性耳聋的治疗策略和分子疗法提供信息。