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.

项目概要/摘要 我们的听觉能力依赖于内耳中一小群专门的感觉“毛”细胞 超过 100 个人类基因的变异与耳聋有关， 其中许多改变了毛细胞中感觉细胞器（称为毛束）的结构。 由毛细胞表面有组织的、高度分级的膜突起或静纤毛组成。 发育过程中发束的形成及其在生命过程中的精确结构很容易受到 各种遗传、环境和年龄相关的损伤，所有这些都会导致衰退或完全丧失 我的首要目标是表征对发束至关重要的蛋白质相互作用。 在这个提案中，我确定了钙结合的新作用。 蛋白质富含于小鼠毛束，特别是最高的静纤毛的尖端。一组五个。 蛋白质，称为伸长复合物，之前曾报道过在同一隔室中丢失。 该复合体的任何成员都会阻止静纤毛的适当伸长，模糊静纤毛的独特身份 跨行，并导致人类和小鼠严重耳聋。 据报道，小鼠突变体缺乏机电传导通道的关键成分。 表明，通过转导，活跃的发束以某种方式影响伸长因子，因此 我建议本提案中研究的钙结合蛋白是一种新的结合蛋白。 MYO15A 的合作伙伴和调节器，MYO15A 是肌球蛋白马达，可将其他伸长复合物蛋白转运至 MYO15A 是最早与听力损失和 MYO15A 突变相关的蛋白质之一。 是人类遗传性耳聋的第三个最常见的起源，该提案的目标 1 将确定 MYO15A 和我们的钙结合蛋白之间的关系，并证实了初步结果表明 这种新蛋白质对于听觉功能至关重要，目标 2 将研究钙水平的变化。 转导时发束中的蛋白质影响其动态定位及其伸长 这些目标共同确定并研究了这种新的静纤毛蛋白作为复杂的合作伙伴。 关键伸长复合物的附加成员，并作为读取毛细胞转导的介质 该项目采用先进的尖端小鼠模型。 培养听觉器官的技术，以及保存的活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 毛细胞的正确发育和终生保存。