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运输是如何发生的，以及运输缺陷如何导致神经退行性疾病的发生和进展。细胞质动力蛋白在细胞内运输中起着重要作用，当它向微管的负端移动时产生力。我们之前已经证明，细胞质动力蛋白在不与微管分离的情况下采取多个步骤的能力，称为进程性，是由动力蛋白激活剂dynactin增强的。在之前的资助期内，我们发现dynactin实际上包含两个不同的微管结合结构域，其中一个基本结构域是dynactin增强动力蛋白加工能力所必需的。进行性远程运动在神经元的轴突过程中尤为重要，在轴突过程中，细胞质动力蛋白逆行运动的距离从微米到米不等。细胞质动力蛋白和动力蛋白运动机械成分的遗传病变已被证明可以改变轴突运输，并在某些情况下导致严重的神经退行性疾病，如肌萎缩性侧索硬化症（ALS）、远端脊髓和球性肌萎缩症（dSBMA）和佩里综合征。我们的假设是动力蛋白p150的基本结构域在运动过程中作为分子系绳维持动力蛋白、动力蛋白、货物和微管之间的接触。在之前的资助期间，我们扩大了我们的兴趣范围，超出了动力蛋白-微管相互作用，还包括通过其他机制调节基于动力蛋白的运输，试图更好地理解基于动力蛋白的细胞运输的复杂性。本提案的目标是测试我们的动力蛋白在动力蛋白为基础的货物运输中如何发挥作用的模型，并确定其他细胞因子在动力蛋白为基础的货物运输中的作用。我们将利用体内和体外对动力蛋白和动力蛋白功能的测定来测试我们的模型，以了解动力蛋白为基础的货物运输是如何正常发生的，以及它在神经退行性疾病期间是如何改变的。

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. PUBLIC HEALTH RELEVANCE: A wide range of human health problems from neurodegeneration to cancer may be caused or compounded by the aberrant function of the cytoplasmic dynein and dynactin motor complex. Our studies aim to elucidate how the specific molecular changes resulting from genetic defects alter dynein and dynactin function to cause diseases such as amyotrophic lateral sclerosis (ALS), distal spinal and bulbar muscular atrophy (dSBMA), and Perry Syndrome. A greater understanding of the molecular mechanisms of dynein and dynactin dysfunction underlying these diseases may lead to therapeutic intervention for these neurodegenerative diseases.