Control of dynein transport by cellular factors

描述（由申请人提供）：我们的最终目标是了解细胞内转运如何发生以及转运缺陷如何导致神经退行性疾病的发生和进展。在细胞内运输中起重要作用的一种细胞骨架马达是细胞质动力蛋白，当它向微管的负端移动时产生力。我们以前已经表明，细胞质动力蛋白采取多个步骤而不从微管中解离的能力，称为持续合成能力，是由动力蛋白激活剂，dynactin增强。在上一个资助期，我们发现dynactin实际上包含两个不同的微管结合域，其中一个是基本域，是dynactin增强动力蛋白合成能力所必需的。进行性长距离运动在神经元的轴突过程中特别重要，其中细胞质动力蛋白在微米至米的距离范围内逆行运输货物。细胞质动力蛋白和动力肌动蛋白运动机制的组分中的遗传损伤已显示改变轴突运输，并且在某些情况下导致严重的神经退行性疾病，例如肌萎缩性侧索硬化症（ALS）和远端脊髓和延髓肌萎缩症（dSBMA）以及佩里综合征。我们的假设是，动力蛋白p150的基本结构域作为一个分子系链，以保持动力蛋白，动力蛋白，货物和微管之间的联系，在运动事件。在上一个资助期间，我们将我们的兴趣扩展到动力蛋白-微管相互作用之外，还包括通过其他机制调节基于动力蛋白的运输，以更好地理解基于细胞动力蛋白的运输的复杂性。本提案的目标是测试我们的模型，动力蛋白为基础的货物运输的dynactin功能，并确定额外的细胞因子在动力蛋白为基础的货物运输的作用。我们将利用动力蛋白和动力肌动蛋白功能的体外和体内测定来测试我们的模型，以了解基于动力蛋白的货物运输通常如何发生以及在神经退行性疾病期间如何改变。

DESCRIPTION (provided by applicant): Our ultimate goal is to understand how intracellular transport occurs and how defects in transport may lead to the onset and progression of neurodegenerative disease. One cytoskeletal motor that plays an important role in intracellular transport is cytoplasmic dynein, which generates force as it moves toward the minus ends of microtubules. We have previously shown that the ability of cytoplasmic dynein to take multiple steps without dissociating from the microtubule, called processivity, is enhanced by the dynein activator, dynactin. In the previous funding period, we discovered that dynactin actually contains two different microtubule-binding domains and that one of these, the basic domain, is required for dynactin to enhance dynein processivity. Processive long-range movements are especially important in the axonal processes of neurons where cytoplasmic dynein moves retrograde cargo over distances ranging from microns to meters. Genetic lesions in components of the cytoplasmic dynein and dynactin motor machinery have been shown to alter axonal transport and in some cases to result in severe neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), and distal spinal and bulbar muscular atrophy (dSBMA), and Perry syndrome. Our hypothesis is that the basic domain of dynactin p150 acts as a molecular tether to maintain contact between dynein, dynactin, cargo and the microtubule during motility events. During the previous funding period, we expanded our interests beyond dynactin-microtubule interactions to also include regulation of dynein-based transport by additional mechanisms in an attempt to better understand the complexity of cellular dynein-based transport. The goals of this proposal are to test our model of how dynactin functions in dynein-based cargo transport and to determine the roles that additional cellular factors have in dynein-based cargo transport. We will utilize both in vitro and in vivo assays of dynein and dynactin function to test our models for how dynein-based cargo transport normally occurs and how it may be altered during neurodegenerative disease.