Control of dynein transport by cellular factors

描述(申请人提供)：我们的最终目标是了解细胞内转运是如何发生的，以及转运缺陷如何导致神经退行性疾病的发生和发展。在细胞内运输中起重要作用的一个细胞骨架马达是细胞质动力蛋白，它在向微管的负端移动时产生力量。我们之前已经证明，细胞质动力蛋白在不脱离微管的情况下采取多个步骤的能力，称为加工性，被动力蛋白激活剂Dynactin增强。在之前的资助期间，我们发现dynactin实际上包含两个不同的微管结合结构域，其中一个是dynactin增强dynein处理能力所必需的基本结构域。持续的远距离运动在神经元的轴突中尤其重要，在那里，细胞质动力蛋白以从微米到米的距离逆行移动货物。细胞质动力蛋白和动力蛋白运动机械组件中的遗传损伤已被证明改变轴突运输，在某些情况下会导致严重的神经退行性疾病，如肌萎缩侧索硬化症(ALS)、远端脊髓和延髓肌肉萎缩(DSBMA)以及Perry综合征。我们的假设是，在运动事件中，dynactin P150的基本结构域起到分子系绳的作用，维持dynein、dynactin、Cargo和微管之间的联系。在之前的资助期间，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，以试图更好地了解细胞基于动力蛋白的运输的复杂性。这项提案的目标是测试我们的模型，即动力蛋白如何在基于动力蛋白的货物运输中发挥作用，并确定额外的细胞因子在基于动力蛋白的货物运输中所起的作用。我们将利用动力蛋白和动力蛋白功能的体外和体内测试来测试我们的模型，以了解基于动力蛋白的货物运输通常是如何发生的，以及在神经退行性疾病期间它可能会如何改变。

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.