Molecular Analysis of Dynein Isoforms

动力蛋白是一种“驱动”分子沿着微管转运的蛋白质。动力蛋白负责纤毛和鞭毛跳动、细胞器运输（包括轴突运输）和有丝分裂后期运动的各个方面。动力蛋白的不同同工异构体被认为执行这些功能。据推测，动力蛋白是所有动力蛋白共有的运动结构域和每个同工异构体特有的系链结构域的复合物，这些结构域定义了同工异构体的位置，并将动力蛋白连接到沿微管易位的分子上。该项目的长期目标是确定在发育中的海胆胚胎中表达的动力蛋白同工异构体的结构，这是研究动力蛋白同工异构体的良好系统。海胆轴突动力蛋白重链的完整序列已被确定。目前这个为期三年的项目的目标是沿着β链的长度产生一个针对选定表位的单克隆抗体库，利用抗体来确定暴露在天然动力蛋白分子表面的表位。并开始探索同工异构体特异性表位。该项目将为阐明动力蛋白活性的分子机制提供重要的新信息，并最终导致对动力蛋白异构体功能多样性的结构基础的理解。

Dynein is a protein which "powers" the translocation of molecules along microtubules. Dynein is responsible for ciliary and flagellar beating, organelle transport (including axonal transport), and aspects of mitotic anaphase motion. Distinct isoforms of dynein are thought to perform each of these functions. It is hypothesized that dynein is the composite of motor domains that are common to all dyneins and tether domains that are unique to each isoform and that define the location of the isoform and link the dynein to the molecule that is translocated along the microtubule. The long term objective of this project is to determine the structures of dynein isoforms that are expressed in the developing sea urchin embryo, an excellent system for the study of dynein isoforms. The complete sequence of sea urchin axonemal dynein beta heavy chain has recently been determined. The goals of the current three year project are to produce a library of monoclonal antibodies to selected epitopes along the length of the beta chain, to use the antibodies to determine what epitopes are exposed on the surface of the native dynein molecule, and to begin the exploration of isoform-specific epitopes. This project will provide new information that is critical for the elucidation of the molecular mechanism of dynein activity, and will lead to an eventual understanding of the structural basis for dynein isoform functional diversity.