A small calcium-binding protein may be key to stabilizing the sensory hair cell stereocilia Elongation Complex

一种小的钙结合蛋白可能是稳定感觉毛细胞静纤毛伸长复合物的关键

• 批准号: 10580594
• 负责人: Ellen I Hartig
• 金额: $ 4.34万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10580594
• 关键词: Ablation; Actins; Adult; Affect; Architecture; Auditory; Basic Science; Behavior; Binding; Biology; Birds; CRISPR/Cas technology; Calcium; Calcium ion; Calcium-Binding Proteins; Cochlea; Complete Hearing Loss; Complex; Data; Defect; Development; Dimensions; Dysmorphology; EF-Hand Domain; Elements; Elongation Factor; Ensure; Environment; Genes; Genetic; Goals; Growth; Hair; Hair Cells; Hearing; Hearing Tests; Height; Heredity; Hour; Human; Image; Knockout Mice; Knowledge; Labyrinth; Letters; Life; Light; Link; Maintenance; Mediating; Mediator; Membrane; Molecular Conformation; Morphogenesis; Morphology; Motor; Mus; Mutant Strains Mice; Mutate; Mutation; Myosin ATPase; Natural regeneration; Organ; Organelles; Pattern; Pharmaceutical Preparations; Phenotype; Population; Presbycusis; Preventive; Protein Isoforms; Proteins; RNA Splicing; Reporting; Research; Role; Sensory; Sensory Hair; Structure; Surface; Techniques; Testing; Therapeutic; Time; Transgenic Mice; Trimethoprim-Sulfamethoxazole; Variant; Work; age related; antibody detection; cell type; cellular transduction; congenital deafness; deaf; deafness; experimental study; hearing impairment; high resolution imaging; in vivo; mechanical stimulus; mechanotransduction; member; mouse model; mutant; novel; pharmacologic; postnatal; preservation; prevent; protein complex; sound

PROJECT SUMMARY/ABSTRACT Our ability to hear relies on a small population of specialized sensory ‘hair’ cells in the inner ear that cannot regenerate upon damage. Variants of over 100 human genes have been associated with deafness, many of which alter the structure of the sensory organelle in hair cells, called the hair bundle. The hair bundle consists of organized rows of graded-height membrane protrusions, or stereocilia, on the surface of hair cells. Hair bundle formation during development and its precise architecture during life are vulnerable to a variety of genetic, environmental, and age-related insults, all of which result in the decline or complete loss of hearing ability. My overarching goal is to characterize protein interactions that are vital to the hair bundle’s development and lifelong maintenance. In this proposal, I identify a new role for a calcium-binding protein enriched in the mouse hair bundle, specifically, at the tip of the tallest stereocilia. A group of five proteins, referred to as the Elongation Complex, was previously reported at this same compartment. Loss of any member of this complex prevents proper stereocilia elongation, blurs the distinct identity of stereocilia across rows, and results in profound deafness in both humans and mice. Interestingly, similar defects have been reported in mouse mutants lacking key components of the mechanoelectrical transduction channel. This suggests that, via transduction, active hair bundles somehow influence elongation factors, and thus stereocilia dimensions. I propose that the calcium-binding protein studied in this proposal is a new binding partner and regulator for MYO15A, the myosin motor that transports other Elongation Complex proteins to stereocilia tips. MYO15A was one of the first proteins associated with hearing loss, and MYO15A mutations are the third most common origin of heredity deafness in humans. Aim 1 of this proposal will determine the relationship between MYO15A and our calcium-binding protein, and confirm preliminary results suggesting that this new protein is essential for auditory function. Aim 2 will investigate how changes in calcium levels in the hair bundle upon transduction affect the dynamic localization of our protein and its Elongation Complex partners. Together, these aims identify and investigate this new stereocilia protein as an additional member of the crucial Elongation Complex, and as a mediator that reads hair cell transduction activity to influence stereocilia growth. This project employs cutting- edge mouse models, advanced techniques to culture the auditory organ, and high-resolution imaging of preserved and live hair cells. Completion of the project will contribute to my long-term goal of informing therapeutic strategies to ensure the proper development and lifelong preservation of hair cells.

项目摘要/摘要 我们听到的能力依赖于内耳中少数专业的感觉“头发”细胞 无法在损坏时再生。超过100个人类基因的变体与死亡有关， 其中许多改变了毛细胞中感觉细胞的结构，称为头发束。 由毛细胞表面上的分级高膜蛋白或立体胶质的有组织的行组成。 发育过程中的头发束形成及其在生活中的精确体系结构很容易受到影响 各种遗传，环境和与年龄有关的事件，所有这些事件都导致下降或完全损失 听力能力。我的总体目标是表征对头发束至关重要的蛋白质相互作用 开发和终身维护。在此提案中，我确定了钙结合的新角色 蛋白质富含小鼠头发束，特别是在最高的立体尾囊的尖端。一组五个 蛋白质（称为延伸复合物）先前在同一隔室中报道。损失 该络合物的任何成员都可以防止适当的立体伸长率延伸，从而使立体膜的独特身份呈现 遍布行，并导致人类和小鼠的严重死亡。有趣的是，类似的缺陷有 在缺乏机械电转移通道的关键成分的小鼠突变体中报道。这 暗示通过翻译，主动头发以某种方式捆绑了伸长因子，因此 立体胶质尺寸。我建议该提案中的钙结合蛋白研究是一种新的结合 Myo15a的合作伙伴和调节剂，肌球蛋白电机将其他伸长率复合蛋白运送到 立体尾tip。 Myo15a是与听力损失相关的第一个蛋白质之一，Myo15a突变 是人类遗产死亡的第三大源头。本提案的目标1将决定 MyO15a与我们的钙结合蛋白之间的关系，并确认初步结果表明 这种新蛋白对于听觉功能至关重要。 AIM 2将研究钙水平的变化 翻译时的头发束会影响我们蛋白质及其伸长的动态定位 复杂的合作伙伴。这些目的共同确定并研究了这种新的立体胶质蛋白 关键伸长复合物的其他成员，作为读取毛细胞转移的介体 影响立体猫生长的活动。该项目采用剪切鼠标模型，高级 培养听觉器官的技术以及保存和活细胞的高分辨率成像。 该项目的完成将有助于我的长期目标，以告知治疗策略以确保 毛细胞的适当发育和终身保存。