Structure-Function Analysis of Sarcospan

项目摘要 肌细胞粘附的丧失正在成为肌营养不良症的共同主题。在骨骼肌中， 肌营养不良蛋白-糖蛋白复合物位于肌膜上，由外周和整体组成， 膜蛋白作为一个整体，这种复合物将细胞外基质连接到细胞内肌动蛋白 在肌肉收缩期间，细胞骨架和肌膜提供结构稳定性。Duchenne 肌营养不良症是最常见的营养不良症，是由肌营养不良蛋白基因突变引起的， 导致肌营养不良蛋白和整个肌营养不良蛋白-糖蛋白复合物的损失。我的研究小组 开创了几个与sarcospan功能相关的关键发现，sarcospan是 肌营养不良蛋白-糖蛋白复合物。我们已经表明，sarcospan在介导蛋白质 在这个复杂的互动。Sarcospan影响肌营养不良蛋白-糖蛋白之间的通讯 复合物和细胞外基质。重要的是，我们证明了在mdx中轻微的sarcospan过度表达， 在鼠抗肌萎缩蛋白基因中具有突变的小鼠，通过稳定 功能上类似于肌营养不良蛋白-糖蛋白的补偿蛋白复合物的表达 复合物，包括α 7 β 1整联蛋白。目前的4 R 01提案建立在前一个时期的发现基础上。 通过询问sarcospan改善肌营养不良蛋白疾病的具体机制， 缺陷型mdx小鼠。我们将检验sarcospan由外向内和由内而外增强a7 b1整合素的假设。 出信号。我们将研究mdx肌肉的细胞外基质， 确定sarcospan如何影响细胞外基质的组成、组织和机械特性， 矩阵最后，我们将使用我们的脱细胞方案分离细胞外基质，并测试其 与人iPSC衍生的骨骼肌祖细胞的相互作用，以测试双向 在新开发的体外模型系统中进行通信。我们希望我们的研究结果能说明 对抗由于细胞外基质损失引起的广泛肌肉萎缩疾病的分子途径 contact.

PROJECT ABSTRACT Loss of muscle cell adhesion is emerging as a common theme in muscular dystrophies. In skeletal muscle, the dystrophin-glycoprotein complex is located at the sarcolemma and is composed of peripheral and integral membrane proteins. As a whole, this complex links the extracellular matrix to the intracellular actin cytoskeleton and provides structural stability to the sarcolemma during muscle contraction. Duchenne muscular dystrophy, the most common form of dystrophy, is caused by mutations in the dystrophin gene that result in loss of dystrophin protein and the entire dystrophin-glycoprotein complex. My research group has pioneered several key discoveries related to the function of sarcospan, an integral component of the dystrophin-glycoprotein complex. We have shown that sarcospan plays an important role in mediating protein interactions within this complex. Sarcospan affects communication between the dystrophin-glycoprotein complex and the extracellular matrix. Importantly, we demonstrate that mild sarcospan over-expression in mdx mice, which possess a mutation in the murine dystrophin gene, rescues muscular dystrophy by stabilizing expression of a complex of compensatory proteins that is functionally analogous to the dystrophin-glycoprotein complex, including a7b1 integrin. The current 4R01 proposal builds on discoveries made during the prior funding periods by interrogating specific mechanisms by which sarcospan ameliorates disease in dystrophin- deficient mdx mice. We will test the hypothesis that sarcospan enhances a7b1 integrin outside-in and inside- out signaling. We will investigate the extracellular matrix of mdx muscle that is overexpressing sarcospan to determine how sarcospan affects the composition, organization, and mechanical properties of the extracellular matrix. Lastly, we will use our decellularization protocol to isolate the extracellular matrix and test its interaction with human iPSC-derived skeletal muscle progenitors to test principles of bidirectional communication in a newly developed in vitro model system. We expect that our results will illuminate molecular pathways that counter a broad range of muscle wasting disorders due to loss of extracellular matrix contact.