The role of Fbxl22 in the regulation of skeletal muscle mass

项目摘要/摘要 骨骼肌萎缩是许多慢性疾病和状况的结果，例如 停用。肌肉萎缩过程的中心是蛋白质降解，对此E3泛素 连接酶在针对特定蛋白质进行降解方面是至关重要的。多种E3泛素的作用 肌肉中的连接酶是未知的，特定的底物还没有确定。总体目标 这项建议的目的是确定E3连接酶、F-box和富含亮氨酸的重复蛋白22的作用 (Fbxl22)，在骨骼肌萎缩中。我的中心假设是Fbxl22对于 肌肉萎缩的过程。强劲的初步数据支持这一假设：1)Fbx122mRNA 在神经原性肌肉萎缩模型中3天后诱导表达，2)过表达 后肢肌肉中的Fbxl22导致总泛素化蛋白显著升高。我建议 两个具体目标： 具体目标1：确定Fbxl22亚型在骨骼肌萎缩中的功能作用， 受伤和再生。我将通过Fbxl22基因的敲除和过表达来解决这个目标 神经原性肌萎缩模型中的异构体和急性肌萎缩模型中Fbx122亚型的表达 肌肉损伤模型。 具体目标2：确定Fbxl22依赖泛素化的底物靶点。这就做 利用Fbxl22基因操作和蛋白质组学分析相结合的方法来解决这一目标 以及Fbx122依赖底物上泛素基序的翻译后修饰鉴定。 随着这项提议的完成，我预计将确定新的机制，以 了解肌肉萎缩的过程。通过确定骨骼肌的机制 萎缩，我们可以探索新的治疗策略来改善个人的生活质量，在 肌肉萎缩是存在的。 爱荷华大学对其学员和初级教职员工的支持由来已久。 我的导师博丁教授是骨骼肌生理学、萎缩和肥大方面的世界领先者。 这一K01奖项将扩大我在泛素蛋白质组学和骨骼肌萎缩方面的研究技能。 这些工具可能有助于识别新的治疗策略，以减轻有害的 骨骼肌萎缩的影响。

Project Summary/Abstract Skeletal muscle atrophy occurs as a consequence of many chronic diseases and conditions such as disuse. Central to the process of muscle atrophy is protein degradation, for which the E3 ubiquitin ligases are critical in targeting specific proteins for degradation. The roles of many E3 ubiquitin ligases in muscle are unknown and specific substrates have yet to be identified. The overall objective of this proposal is to determine the role of the E3 ligase, F-box and leucine-rich repeat protein 22 (Fbxl22), in skeletal muscle atrophy. My central hypothesis is that Fbxl22 is necessary for the process of muscle atrophy. Robust preliminary data supports this hypothesis: 1) Fbxl22 mRNA expression is induced after 3 days in a model of neurogenic muscle atrophy, 2) Overexpression of Fbxl22 in hindlimb muscles results in significant elevations of total ubiquitinated proteins. I propose two specific aims: Specific Aim 1: Determine the functional role of Fbxl22 isoforms in skeletal muscle atrophy, injury and regrowth. I will address this aim using knockdown and overexpression of Fbxl22 gene isoforms in a model of neurogenic muscle atrophy and assess Fbxl22 isoform expression in an acute muscle injury model. Specific Aim 2: To identify substrate targets for Fbxl22-dependent ubiquitination. I will address this aim using a combined approach of Fbxl22 gene manipulation with proteomics analysis and post-translational modification identification of ubiquitin motifs on Fbxl22-dependent substrates. With the completion of this proposal, I expect to have identified novel mechanisms for understanding the muscle atrophy process. By identifying the mechanisms of skeletal muscle atrophy, we can explore new therapeutic strategies for improving an individual’s quality of life where muscle wasting is present. The University of Iowa has a longstanding history of support to its trainees and junior faculty. My mentor, Prof. Bodine is a world leader in skeletal muscle physiology, atrophy and hypertrophy. This K01 award will expand my research skills in ubiquitin proteomics and skeletal muscle atrophy. These tools may enable the identification of new therapeutic strategies for alleviating the detrimental impact of skeletal muscle wasting.