Myoferlin in muscle membrane fusion and repair

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是一种膜相关蛋白，参与囊泡运输事件。在肌肉中，这包括对质膜修复重要的囊泡运动。我们的工作也表明dysferlin和ferlin家族的其他成员一样，调节囊泡的循环。我们的特点myoferlin和Fer 1 L5，两个高度相关的蛋白质dysferlin了解这些蛋白质是否有重叠的功能，以取代dysferlin。这些ferlin蛋白各自具有至少六个C2结构域，这些结构域对于蛋白质-膜和蛋白质-蛋白质相互作用是重要的。我们发现，第一个C2结构域的dysferlin结合带负电荷的磷脂在钙敏感的方式。我们随后表明，ferlin C2结构域直接结合到羧基末端Eps 15同源结构域（EHD）蛋白，和EHD蛋白所需的ferlin细胞内运输。EHD蛋白在体外和细胞内均可诱导肾小管形成。我们将研究ferlin、EHD和Bin 1在肌肉横小管发生中的相互作用。然后，我们将研究ferlin蛋白的丢失使肌肉容易发生去小管化的机制，以及恢复小管形成和功能的分子要求。最后，我们将研究ferlin蛋白介导的回收事件。在每一步中，我们将确定dysferlin的结构域，或介导这些事件的相关myoferlin和Fer 1 L5，并评估这些功能的恢复是否纠正了dysferlin相关肌营养不良症的潜在病理学。

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.