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 我们的听力依赖于内耳中一小部分专门的感觉“毛发”细胞。 损坏后不能再生。超过100个人类基因的变异与耳聋有关， 其中许多会改变毛细胞中感觉细胞器的结构，称为发束。发束 由毛细胞表面的一排排有组织的高度渐变的膜突起或立体纤毛组成。 毛束在发育过程中的形成及其在生命中的精确结构容易受到 各种与遗传、环境和年龄相关的侮辱，所有这些都会导致衰退或完全丧失 对听力的影响。我的首要目标是描述对发束的蛋白质相互作用是至关重要的 开发和终身维护。在这项提案中，我确定了钙结合蛋白的新角色 蛋白质富含在小鼠的发束中，特别是在最高的立体纤毛的顶端。五个人的小组 蛋白质，被称为延伸复合体，以前在这个隔室中被报道过。损失 这种复合体的任何成员都会阻止立体纤毛的适当伸长，模糊了立体纤毛的独特身份。 并导致人类和小鼠的严重耳聋。有趣的是，类似的缺陷也有 据报道，在缺乏机械电转导通道关键组件的小鼠突变体中。这 这表明，通过转导，活跃的发束以某种方式影响伸长因子，从而 立体纤毛的维度。我认为这个方案中研究的钙结合蛋白是一种新的结合蛋白。 MYO15A的合作伙伴和调节者，肌球蛋白马达将其他伸长复合体蛋白输送到 立体纤毛尖端。MYO15A是最早与听力损失相关的蛋白质之一，MYO15A突变 是人类遗传性耳聋的第三大常见来源。本提案的目标1将决定 MYO15A与我们的钙结合蛋白的关系，并证实了初步结果表明 这种新的蛋白质对听觉功能是必不可少的。目标2将研究钙水平如何变化 在转导后的发束中影响我们蛋白质的动态定位和它的延伸 复杂的合伙人。总之，这些目标识别和研究这种新的立体纤毛蛋白作为一种 关键的伸长复合体的额外成员，作为阅读毛细胞转导的媒介 影响立体纤毛生长的活动。该项目采用了尖端的鼠标型号，高级 培养听觉器官的技术，以及保存和活的毛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，即告知治疗策略，以确保 毛细胞的正常发育和终生保存。