ORGANELLE MOVEMENT IN FAST AXONAL TRANSPORT

描述神经元细胞体是大多数轴突蛋白的位点。 合成. 因此，维持和生长所需的物质 轴突必须从细胞体沿着轴突运输到 终端 因此，轴突运输对于神经生长和神经再生是重要的。 轴突运输的缺陷导致神经变性 和疾病 这个项目的目标是了解一个组成部分， 轴突运输，膜细胞器和它们的货物， 在快速轴突运输中沿着轴突运输。 两个基于微管的 蛋白质是这种运动的发动机。 驱动蛋白是 细胞器在顺行方向的运输（从细胞体到 轴突末端），而细胞质动力蛋白在逆行中移动细胞器 方向，从终端到细胞体。 然而，许多关于 细胞器顺行和逆行运动的协调仍然是 解释一下 这个建议集中在逆行马达上， 细胞质动力蛋白 已经发现，不同的动力蛋白复合物， 通过动力蛋白中间链的不同亚型来区分 亚基（IC 74）沿着轴突顺向运输 在两个不同的隔间里 一个动力蛋白池在缓慢的轴突中移动 第二个池与膜细胞器有关 由驱动蛋白驱动。 本提案的目的是了解该法规 以及这两个动力蛋白顺行池与 逆行动力蛋白马达 表位标记的IC74同种型将在 转染到培养的细胞中，并鉴定 与体内逆行移动的细胞器有关， 测定 不同的动力蛋白复合物将被纯化， 将确定每个复合物的功能特性，包括ATP酶 活性、体外运动性和细胞器结合。 差异 已经鉴定了动力蛋白复合物的磷酸化状态。 的 动力蛋白的磷酸化状态将在体外被操纵， 将确定磷酸化在调节动力蛋白性质中的作用。

DESCRIPTION The neuronal cell body is the site of most axonal protein synthesis. Therefore, material necessary for the maintenance and growth of the axon must be transported from the cell body along the axon to the terminal. Thus, axonal transport is important for nerve growth and regeneration, and defects in axonal transport result in neurodegeneration and disease. The goal of this project is to understand one component of axonal transport, how membranous organelles, and their cargo, are transported along the axon in fast axonal transport. Two microtubule-based proteins are the motors for this movement. Kinesin is the motor for organelle transport in the anterograde direction (from the cell body to the axon terminal) while cytoplasmic dynein moves organelles in the retrograde direction, from the terminal to the cell body. However, many details about the coordination of anterograde and retrograde organelle movements remain to be explained. This proposal concentrates on the retrograde motor, cytoplasmic dynein. It has been found that distinct dynein complexes, which are distinguished by different isoforms of the dynein intermediate chain subunit (IC74), are transported along the axon in the anterograde direction in two different compartments. One pool of dynein is moving in slow axonal transport, and a second pool is associated with the membranous organelles moved by kinesin. The goal of this proposal is to understand the regulation of dynein and the relationship of these two anterograde pools of dynein to the retrograde dynein motor. Epitope tagged IC74 isoforms will be transfected into cultured cells and the identity of the IC74 isoforms which are associated with retrogradely moving organelles in vivo will be determined. The different dynein complexes will be purified and the functional properties of each complex will be determined, including ATPase activity, in vitro motility, and organelle binding. Differences in the phosphorylation state of the dynein complexes have been identified. The phosphorylation state of dynein will be manipulated in vitro and the role of phosphorylation in regulating the properties of dynein will be determined.