ALPHA ACTININS IN NORMALS AND DISEASED MUSCLE

本申请旨在支持艾伦的职业发展。 H.贝格斯，博士，儿童医院儿科学助理教授 医院和哈佛医学院。申请人的职业目标 将继续发展一项强有力的独立研究计划 在肌肉生物学和人类神经肌肉疾病的丰富和 波士顿生物医学研究的刺激环境 社区。通过KO2机制提供的工资支持将使他能够 从事全职研究，无需执行服务 运行临床诊断实验室等职能。这个 这项提议的科学目标是理解结构， 肌肉特异性α-受体的功能和蛋白质相互作用 并将这些信息应用于人类的研究 神经肌肉疾病。α-肌动蛋白是一个密切相关的家族 相关的肌动蛋白结合蛋白，起到交联和锚定的作用 肌动蛋白细丝。在肌肉中，钙不敏感的α-肌动蛋白 Z线的主要组成部分，在这里它们构成锚定 含有肌动蛋白/星云蛋白的细丝。一些人类 神经肌肉疾病已被证明是由基因突变引起的 肌肉特有的细胞骨架元素。同样，有几个人继承了 心肌病是由心脏基因突变引起的。 肌节蛋白的特定异构体。据推测， 一些人类神经肌肉疾病可能是由基因突变引起的 肌肉特异的α-肌动蛋白基因，和/或蛋白质的基因 与α-肌动蛋白相互作用。申请人已克隆并 鉴定了人类o：-肌动蛋白的三个基因，最近 确认了几名先天性肌营养不良症患者 缺乏一种肌肉特异性亚型的表达。这 建议涉及：L)在其他方面扩展了这一观察 原发性肌肉疾病患者及其基因突变的鉴定 缺陷患者的o(-肌动蛋白)基因中；2)进一步 L-肌动蛋白在正常组织中的特征；3)发育中的细胞 α-肌动蛋白功能障碍的培养和转基因小鼠模型； 4)识别与α-蛋白相互作用的新蛋白的基因 肌动蛋白；5)这些新基因和蛋白质的特征：和6) 评估这些基因作为其他人类神经肌肉的候选基因 疾病。直接的临床益处将包括准确的预检和 对这些疾病的出生后诊断，更好地了解 他们的潜在病因，以及对潜在疗法的洞察。 这些实验也将增加我们对α-肌动蛋白的理解 发挥作用，并确定与现有和新的互动 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.