ALPHA ACTININS IN NORMALS AND DISEASED MUSCLE

本申请旨在支持Alan的职业发展 H. Beggs博士，儿童医院儿科助理教授 医院和哈佛医学院。申请人的职业目标 将继续发展一个充满活力的独立研究项目 在肌肉生物学和人类神经肌肉疾病中， 波士顿生物医学研究所的环境 社区通过KO 2机制提供的工资支持将使他能够 从事全职研究，而不必提供服务 如运行临床诊断实验室。的 这个提议的科学目标是了解这些结构， 功能和蛋白质相互作用的肌肉特异性α- 肌动蛋白，并将此信息应用于人类 神经肌肉疾病α-辅肌动蛋白是一个家族， 起交联和锚作用的相关肌动蛋白结合蛋白 肌动蛋白丝在肌肉中，钙不敏感的α-辅肌动蛋白是 Z线的主要组成部分，它们组成性地锚在 包含肌动蛋白/星云蛋白的细丝。许多人类 神经肌肉疾病已被证明是由基因突变引起的。 肌肉特异性细胞骨架元素。同样，几个继承了 心肌病是由心脏基因突变引起的， 肌节蛋白的特异性同种型。它是假设 一些人类神经肌肉疾病可能是由以下基因突变引起的： 肌肉特异性α-辅肌动蛋白基因，和/或蛋白质基因 与α辅肌动蛋白相互作用。申请人已克隆和 鉴定了人类o：-辅肌动蛋白的三个基因，最近 发现了几名先天性肌营养不良症患者， 缺乏肌肉特异性同种型之一的表达。这 建议包括：（l）将这一意见扩大到 患有原发性肌肉疾病和识别突变的患者 在缺陷患者的o（-辅肌动蛋白基因中; 2）进一步 表征（正常组织中的L-辅肌动蛋白; 3）发育中的细胞 α-辅肌动蛋白功能障碍的培养和转基因小鼠模型; 4)识别与α-淀粉酶相互作用的新蛋白质的基因， 辅肌动蛋白; 5）表征这些新基因和蛋白质;以及6） 评估这些作为其他人类神经肌肉的候选基因 疾病直接的临床受益将包括准确的术前和 产后诊断这些疾病，更好地了解 他们的潜在病因，以及对潜在疗法的见解。 这些实验也将增加我们对α-辅肌动蛋白的了解 功能和识别新的相互作用， Z线和其他地方的肌肉蛋白质。

This application proposes to support the career development of Alan H. Beggs, Ph.D., an Assistant Professor of Pediatrics at Children's Hospital and Harvard Medical School. The applicant's career goals are to continue developing a vigorous independent research program in muscle biology and human neuromuscular disease in the rich and stimulating environment of the Boston biomedical research community. Salary support via the KO2 mechanism will allow him to pursue full time research without having to perform a service function such as running a clinical diagnostic laboratory. The scientific goals of this proposal are to understand the structures, functions and protein interactions of muscle-specific alpha- actinins and to apply this information to the study of human neuromuscular disorders. The alpha-actinins are a family of closely related actin-binding proteins that serve to cross link and anchor actin filaments. In muscle, calcium-insensitive alpha-actinins are a major component of Z lines where they constitutively anchor the actin/nebulin-containing thin filaments. A number of human neuromuscular diseases have been shown to result from mutations of muscle-specific cytoskeletal elements. Similarly, several inherited cardiomyopathies are caused by mutations in genes for cardiac- specific isoforms of sarcomeric proteins. It is hypothesized that some human neuromuscular diseases may be caused by mutations in muscle-specific alpha-actinin genes, and/or in genes for proteins that interact with alpha-actinin. The applicant has cloned and characterized three genes for human o:-actinins and has recently identified several patients with congenital muscular dystrophy who lack expression of one of the muscle-specific isoforms. This proposal entails: l) extending this observation in additional patients with primary disorders of muscle and identifying mutations in the o(-actinin genes of deficient patients; 2) further characterizing (L-actinins in normal tissues; 3) developing cell culture and transgenic mouse models of alpha-actinin dysfunction; 4) identifying genes for novel proteins that interact with alpha- actinins; 5) characterizing these new genes and proteins: and 6) assessing these as candidate genes for other human neuromuscular diseases. Direct clinical benefits will include accurate pre- and postnatal diagnoses for these disorders, better understanding of their underlying etiology, and insights into potential therapies. These experiments will also increase our understanding of a-actinin function and identify new interactions with existing and novel muscle proteins at the Z-line and elsewhere.