Role of myosin 1c in adaptation in the inner ear

肌球蛋白 1c 在内耳适应中的作用

• 批准号: 7478235
• 负责人: LYNNE M COLUCCIO
• 金额: $ 10万
• 依托单位: BOSTON BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7478235
• 关键词: ATP phosphohydrolase; Accounting; Actins; Affect; Amino Acids; Animals; Auditory; Binding; Biochemical; Biochemistry; Biological Assay; Calcium; Calcium ion; Calmodulin; Cell physiology; Cells; Class; Closure; Complex; Cytoskeleton; Diagnostic; Disease; Equilibrium; Exhibits; Filament; Goals; Hair Cells; Head Movements; Hearing; In Vitro; Inner Hair Cells; Ion Channel; Kinetics; Knowledge; Laboratories; Labyrinth; Lead; Link; Measures; Mechanics; Modeling; Molecular; Molecular Motors; Motor; Motor Activity; Mus; Mutate; Mutation; Myosin ATPase; Myosin Type I; Nerve; Personal Satisfaction; Process; Property; Range; Rate; Recovery; Rest; Role; Sensory Hair; Stereocilium; Stimulus; Testing; Thinking; Transgenic Mice; Vertigo; Vestibular Hair Cells; Weight-Bearing state; base; cell motility; design; extracellular; hearing impairment; human CDH23 protein; in vivo; insight; link protein; mutant; prevent; receptor; response; single molecule; sound; vibration

The broad, long-range goal of this study is to determine the molecular mechanism of hearing and balance. Actin-filled projections, or stereocilia, on the sensory hair cells of the inner ear convert force produced by sounds and mechanical vibrations into nerve impulses. The prevailing model for mechanotransduction, thought to be well-conserved for both cochlear and vestibular hair cells, is one in which neighboring stereocilia connected by extracellular filaments called tip links, deflect in response to stimuli, thereby causing the opening or closing of transduction channels. The channels are associated with an adaptation-motor complex, which when tension is high, is pulled down the actin cytoskeleton of the stereocilia, reducing tip link tension, and opening the channels; and when tension is low, translocates up the actin cytoskeleton, restoring the resting tension, and closing the Ca2* channels. Localization of the molecular motor, myosin 1c (Myolc) at strategic places in the stereocilia; and studies using transgenic mice expressing a mutant Myolc that can be selectively inhibited have shown Myolc1 s involvement in this process known as adaptation (Holt et al, 2002; Stauffer et al., 2005). Adaptation allows hair cells under prolonged stimuli to remain sensitive to new stimuli. The goal of this proposal is to determine the role of Myolc in specific aspects of adaptation by measuring adaptation in mice expressing Myolc mutants with defined molecular properties. The specific aims are: to characterize the biochemical and mechanical properties of Myolc mutants by in vitro expression followed by characterization by ATPase assays, motility assays, kinetic analyses and single-molecule mechanical studies. Mutants will include those that affect the ability of Myo1 c to adapt to mechanical load, a property predicted for Myolc from previous studies in this laboratory (Batters et al., 2004a; 2004b). Next, the effects of these mutations on adaptation will be tested in vestibular hair cells from knockin mice expressing mutant Myolc. The combined in vitro and animal studies are expected to provide critical, new insight into the molecular mechanism of Myolc and its role in adaptation. This knowledge could ultimately lead to the design of rational diagnostics and therapies to treat diseases of balance and/or hearing.

这项研究的广泛，远程目标是确定听力和平衡的分子机制。 肌动蛋白填充的投影或立体胶质，在内耳的感觉毛细胞上转化由 声音和机械振动成神经冲动。机械传输的盛行模型， 人们认为对人工耳蜗和前庭毛细胞均保存良好，是一个相邻的 由称为尖端链接的细胞外细丝连接的立体胶质，响应刺激，从而导致 转导通道的开放或关闭。这些通道与适应机动器有关 当张力较高时，将复合体拉下了立体胶体的肌动蛋白细胞骨架，减少了尖端链接 紧张并打开频道；当张力低时，会易位肌动蛋白细胞骨架，恢复 静止张力，关闭CA2*通道。分子电动机的定位，肌球蛋白1C（Myolc） 在立体怪物的战略位置；以及使用表达突变体的转基因小鼠的研究，可以 被选择性抑制已显示在此过程中的Myolc1的参与被称为适应（Holt等， 2002; Stauffer等，2005）。适应使长时间刺激下的毛细胞保持对新的敏感 刺激。该提案的目的是确定迈尔克在适应的特定方面的作用 测量具有定义的分子特性的肌动物突变体的小鼠的适应性。具体 目的是：通过体外表达来表征迈尔克突变体的生化和机械性能 然后通过ATPase分析，运动性测定，动力学分析和单分子进行表征 机械研究。突变体将包括影响Myo1 C适应机械负载的能力的突变体，A 从该实验室中的先前研究中预测的Myolc的财产（Batters等，2004a; 2004b）。下一个， 这些突变对适应的影响将在敲蛋白小鼠的前庭毛细胞中进行测试 表达突变的莫尔克。预期在体外和动物研究中将提供关键，新的 深入了解迈尔克的分子机制及其在适应中的作用。这些知识最终可以 导致设计理性诊断和疗法，以治疗平衡和/或听力的疾病。