Structure-Function Analysis of Sarcospan

项目摘要 肌肉细胞粘附性丧失是肌营养不良症的一个共同主题。在骨骼肌中， 肌营养不良蛋白-糖蛋白复合体位于肌膜，由周围型和整体型组成 膜蛋白。作为一个整体，这个复合体将细胞外基质与细胞内肌动蛋白联系起来 细胞骨架，并在肌肉收缩过程中为肌膜提供结构稳定性。杜兴 肌营养不良是最常见的营养不良形式，是由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-糖蛋白复合体的丢失。我的研究小组已经 率先发现了与sarcospan功能有关的几个关键发现，sarcospan是 营养不良蛋白-糖蛋白复合体。我们已经证明，蔗糖在调节蛋白质方面起着重要作用。 在这个综合体内的相互作用。Sarcospan影响肌营养不良蛋白-糖蛋白之间的通讯 复合体和细胞外基质。重要的是，我们证明了mdx中轻度sarcospan的过度表达。 拥有小鼠营养不良蛋白基因突变的小鼠通过稳定肌肉营养不良来拯救肌肉营养不良 一种功能类似于肌营养不良蛋白糖蛋白的补偿蛋白复合体的表达 复合体，包括7b1整合素。当前的4R01提案建立在之前 通过询问SarcSpan改善Dstrophin疾病的特定机制来获得资金- Mdx缺陷小鼠。我们将检验这样的假设，即SarcSpan由外而内和由内而外增强a7b1整合素- 发出信号。我们将研究mdx肌肉的细胞外基质过度表达sarcspan到 确定蔗糖如何影响细胞外膜的组成、组织和机械性能 矩阵。最后，我们将使用我们的脱细胞方案来分离细胞外基质并测试其 与人IPSC来源的骨骼肌祖细胞相互作用以测试双向原理 一种新开发的体外模型系统中的通信。我们希望我们的结果能说明 对抗由细胞外基质丢失引起的广泛肌肉萎缩障碍的分子途径 联系。

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.