Myoferlin in muscle membrane fusion and repair

肌成纤维蛋白在肌肉膜融合和修复中的作用

• 批准号: 8990655
• 负责人: Elizabeth M McNally
• 金额: $ 31.97万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8990655
• 关键词: Myoferlin; muscle; membrane; fusion; repair

DESCRIPTION (provided by applicant): Mutations in dysferlin cause muscular dystrophy, and the mechanism by which loss of dysferlin leads to muscular dystrophy is a fundamentally different than other forms of muscular dystrophy. Dysferlin is a membrane-associated protein that participates in vesicle trafficking events. In muscle this includes vesicle movement important for plasma membrane repair. Our work has also shown that dysferlin, like other members of the ferlin family, regulates vesicle recycling. We characterized myoferlin and Fer1L5, two highly related proteins to dysferlin to understand whether these proteins have overlapping function to substitute for dysferlin. These ferlin proteins each have at least six C2 domains, domains important for protein-membrane and protein-protein interactions. We identified that the first C2 domain of dysferlin binds negatively charged phospholipids in a calcium sensitive manner. We subsequently showed that ferlin C2 domains bind directly to carboxy-terminal Eps 15 Homology Domain (EHD) proteins, and that EHD proteins are required for ferlin intracellular trafficking. EHD proteins can induce tubule formation in vitro and in cell. We will study the interaction between ferlins, EHD, and Bin1 in the genesis of transverse tubule in muscle. We will then examine the mechanisms by which loss of ferlin proteins renders the muscle susceptible to detubulation and the molecular requirements to restore tubule formation and function. Finally, we will examine recycling events mediated by ferlin proteins. In each step, we will determine the domains of dysferlin, or the related myoferlin and Fer1L5 that mediate these events and assess whether restoration of these functions corrects the underlying pathology in dysferlin-associated muscular dystrophy.

描述（由申请人提供）：dysferlin 突变导致肌营养不良，dysferlin 缺失导致肌营养不良的机制与其他形式的肌营养不良有根本不同。 Dysferlin 是一种参与囊泡运输事件的膜相关蛋白。在肌肉中，这包括对质膜修复很重要的囊泡运动。我们的工作还表明，dysferlin 与 ferlin 家族的其他成员一样，调节囊泡回收。我们对肌铁蛋白和 Fer1L5 这两种与 Dysferlin 高度相关的蛋白质进行了表征，以了解这些蛋白质是否具有重叠功能来替代 Dysferlin。这些 ferlin 蛋白各自具有至少 6 个 C2 结构域，这些结构域对于蛋白质-膜和蛋白质-蛋白质相互作用很重要。我们发现 Dysferlin 的第一个 C2 结构域以钙敏感方式结合带负电荷的磷脂。我们随后表明，ferlin C2 结构域直接与羧基末端 Eps 15 同源结构域 (EHD) 蛋白结合，并且 EHD 蛋白是 ferlin 细胞内运输所必需的。 EHD 蛋白可以在体外和细胞内诱导小管形成。我们将研究 ferlins、EHD 和 Bin1 在肌肉横管发生过程中的相互作用。然后，我们将研究 ferlin 蛋白的丢失导致肌肉容易去管的机制，以及恢复小管形成和功能的分子要求。最后，我们将检查由 ferlin 蛋白介导的回收事件。在每个步骤中，我们将确定介导这些事件的 Dysferlin 或相关的 Myoferlin 和 Fer1L5 的结构域，并评估这些功能的恢复是否可以纠正 Dysferlin 相关性肌营养不良症的潜在病理学。