Role of myosin 1c in adaptation in the inner ear

肌球蛋白 1c 在内耳适应中的作用

基本信息

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
项目类别：
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

项目摘要

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、长期目标是确定听力和平衡的分子机制。内耳感觉毛细胞上充满肌动蛋白的突起或静纤毛将由将声音和机械振动转化为神经冲动。流行的力转导模型，人们认为耳蜗毛细胞和前庭毛细胞都保存完好，其中相邻的毛细胞静纤毛由称为尖端链接的细胞外细丝连接，响应刺激而偏转，从而导致转导通道的打开或关闭。这些通道与适应电机相关联当张力较高时，复合体会被拉下静纤毛的肌动蛋白细胞骨架，从而减少尖端连接紧张，打开渠道；当张力较低时，肌动蛋白细胞骨架向上移位，恢复静息张力，并关闭 Ca2* 通道。分子马达肌球蛋白 1c (Myolc) 的定位在静纤毛的战略位置；以及使用表达突变型 Myolc 的转基因小鼠进行的研究，该突变型 Myolc 可以被选择性抑制已表明 Myolc1 参与了这一称为适应的过程（Holt 等人， 2002年；斯托弗等人，2005）。适应使毛细胞在长时间的刺激下保持对新事物的敏感刺激。该提案的目标是确定 Myolc 在适应的具体方面的作用测量表达具有明确分子特性的 Myolc 突变体的小鼠的适应性。具体的目的是：通过体外表达表征 Myolc 突变体的生化和机械特性随后通过 ATP 酶测定、运动测定、动力学分析和单分子进行表征机械研究。突变体将包括那些影响 Myo1 c 适应机械负载能力的突变体， Myolc 的特性是根据该实验室之前的研究预测的（Batters 等人，2004a；2004b）。下一个，这些突变对适应的影响将在敲入小鼠的前庭毛细胞中进行测试表达突变型 Myolc。体外和动物研究相结合预计将提供关键的、新的深入了解 Myolc 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合理的诊断和疗法来治疗平衡和/或听力疾病。