Cytoskeletal dynamics in stereocilia maintenance

描述（由申请人提供）：进行性听力损失是一种常见的人类健康问题，通常源于内耳感觉毛细胞的丧失或功能障碍。肌动蛋白 蛋白质是毛细胞结构和功能的核心;因此，了解细胞骨架维持的分子机制是考虑合理设计年龄相关或噪声诱导的听力损失治疗方法的关键步骤。- 肌动蛋白和？-肌动蛋白是两种不同但密切相关的肌动蛋白亚型，每种亚型都对丝状肌动蛋白的种群有贡献 静纤毛。我们以前已经证明，小鼠的毛细胞缺乏肌动蛋白亚型形成正常的静纤毛，但继续发展不同形式的进行性听力损失。这表明，肌动蛋白和？肌动蛋白各自对静纤毛稳定性做出独特的贡献。该建议集中在静纤毛肌动蛋白生物学的两个方面。在目标1中，我们将使用现有的条件肌动蛋白和？肌动蛋白敲除小鼠品系和新开发的转基因肌动蛋白报告品系，以评估体内静纤毛中的肌动蛋白动力学。在目的2中，我们将使用细胞生物学和生物化学方法来确定肌动蛋白捆绑蛋白fascin 2与β-actin和β-actin之间的差异相互作用。肌动蛋白有助于不同的静纤毛维持机制。总之，这些目标的完成将支持一个新的模型肌动蛋白调节静纤毛维护。从长远来看，我们将使用本提案中建立的同一套通用平台，在分子、细胞和小鼠水平上评估其他致突变肌动蛋白结合蛋白在调节静纤毛肌动蛋白动力学中的作用。

DESCRIPTION (provided by applicant): Progressive hearing loss is a common human health problem that often stems from the loss or dysfunction of sensory hair cells in the inner ear. Actin proteins are central to hair cell structure and function; consequently, understanding the molecular mechanisms of cytoskeletal maintenance is a key step in considering rationally designed therapies for age-related or noise-induced hearing loss. �-Actin and ?-actin, two distinct yet closely related actin isoforms, each contribute to the population of filamentous actin in stereocilia. We have previously shown that mice with hair cells lacking either actin isoform form normal stereocilia, but go on to develop different forms of progressive hearing loss. This suggests that �-Actin and ?-actin each make unique contributions to stereocilia stability. This proposal is focused on two aspects of actin biology in stereocilia. In Aim 1, we will use existing conditional �-Actin and ?-actin knockout mouse lines and a newly developed transgenic actin reporter line to assess actin dynamics in stereocilia in vivo. In Aim 2, we will use cell biologica and biochemical approaches to determine if differential interactions between the actin bundling protein fascin 2 and �-actin and ?-actin contribute to distinct stereocilia maintenance mechanisms. Together, completion of these Aims will support a new model of actin regulation during stereocilia maintenance. In the long term, we will use the same suite of universal platforms established in this proposal to assess the roles of other deafness-causing mutant actin binding proteins in modulating stereocilia actin dynamics at the level of molecules, cells and mice.