MECHANISM OF KINESIN ATPASE

这项研究的长期目标是提供一个更好的理解 细胞内细胞器的运动机制 微管。这种运动在斋戒过程中起着特殊的作用。 神经细胞中的轴突运输。这一过程提供了一种方法 年新合成材料从其合成部位的移动 神经细胞体与轴突末端的突触相连。类似 然而，运动过程也可能在以下方面发挥重要作用 所有真核细胞。例如，膜的定向运动 细胞器与内质网的延伸有关 远离核区的网状细胞和线粒体 某些类型的分泌囊泡向血浆定向运动 薄膜。 该蛋白最近被分离出来，并被证明是一种运动 沿微管顺行方向驱动运动 (对应于神经细胞离开核区的运动 并指向外围)。这种运动的能量来源于 三磷酸腺苷(ATP)的水解，以及纯化的驱动蛋白HAS 微管刺激的ATPase活性。 这个项目的目的是确定详细的酶作用机制。 肌动蛋白/微管运动系统对三磷酸腺苷的水解作用 关于如何将水解性与运动相结合。最近的进展表明， 作为离子的函数，动蛋白经历了很大的构象变化 实力和即将到来的赠款期间的一个主要组成部分是 对这种构象变化的进一步描述及其可能 对肌动蛋白调控的意义。一个重要的方法将是 激动素的各个结构域及其结构域的表征 互动。这些结构域将通过有限的蛋白质分解和通过 肌动蛋白基因片段的表达。这些问题的解决将 允许对以下形式进行更详细的动力学分析 被适当激活的激动素。将广泛使用STRATE 状态和单次周转动力学和免疫学方法。这个 从这些研究中获得的综合信息将使 一种详细的运动机制模型的建立 激动素及其在细胞过程中的作用。

The long range goal of this research is to provide a better understanding of the mechanism of movement of intracellular organelles along microtubules. Such movement plays a special role in the process of fast axonal transport in nerve cells. This process provides one means for the movement of newly synthesized materials from their site of synthesis in the body of a nerve cell to the synapse at the end of the axon. Similar motility processes, however, also are likely to play an important roles in all eukaryotic cells. For example, the directed movement of membranous organelles has been implicated in the extension of the endoplasmic reticulum and mitochondria away from the nuclear region and in the directed movement of some classes of secretory vesicles towards the plasma membrane. The protein kinesin has recently been isolated and shown to be a motor for driving movement along microtubules in the anterograde direction (corresponding to movement in a nerve cell away from the nuclear region and toward the periphery). The energy for this movement is derived from hydrolysis of adenosine triphosphate (ATP), and purified kinesin has ATPase activity which is stimulated by microtubules. The aim of this project is to determine the detailed enzymatic mechanism of ATP hydrolysis by the kinesin/microtubule motility system with emphasis on how hydrolysis is coupled to movement. Recent progress indicates that kinesin undergoes a large conformational change as a function of ionic strength and a major component for the upcoming grant period is the further characterization of this conformational change and its possible significance for the regulation of kinesin. An important approach will be the characterization of individual domains of kinesin and their interaction. These domains will be obtained by limited proteolysis and by expression of fragments of kinesin cDNA. Resolution of these issues will allow a more detailed kinetic analysis to be undertaken on the forms of kinesin which are properly activated. Extensive use will be made of steady state and single turnover kinetics and immunological approaches. The combined information which will be available from these studies will allow the formulation of a detailed model for mechanism of motility induced by kinesin and its role in cellular processes.