CYTOPLASMIC DYNEIN LIGHT CHAIN STRUCTURE AND FUNCTION

细胞质动力蛋白是一种多亚基酶复合物，它将化学能转化为沿沿着的运动。它在内质网和高尔基复合体之间的交通以及膜细胞器的运输中起着广泛的作用。这种运输对于染色体排列和分离、产生和维持细胞器结构和位置以及促进物质在区室之间的转移是必不可少的。组装成功能电机的机制尚不清楚。此外，动力蛋白的任何亚基都没有高分辨率的结构。一个10 kDa的亚基，在这里被称为DLC，是高度保守的所有已知的动力蛋白，94%的序列之间的果蝇和人类的一致性，也是肌球蛋白V的组成部分。高保守性表明一个共同的功能，这种特殊的蛋白质在电机复合体的各种生物。10 kDa的亚基被认为是必不可少的几个细胞过程：胚胎发育和卵子发生在果蝇，核迁移在真菌，形成和维持的血吸虫，跨轴突的神经元型一氧化氮合酶的运输，和病毒感染过程中的转录调控。这些不同功能的机制尚不清楚。该项目的目的是确定DLC的结构特征如何有助于其多重监管作用。共价交联实验表明，这种多肽存在的动力蛋白复合物内的二聚体结构，并与其他两个动力蛋白组分。这里提出的实验将集中在使用核磁共振光谱，以确定二聚体接口，高分辨率的结构和动力学的二聚体，和潜在的网站与蛋白质的相互作用内的动力蛋白复合物和货物。未来的研究可能会集中在二聚化的作用，在体内组装的复合物，动力蛋白的其他亚基的表征，以及它们与DLC的相互作用。DLC的高分辨率结构不仅可以提供线索，其具体的和各种功能，但更重要的是，可能提供一个途径到动力蛋白系统的结构表征。

Cytoplasmic dynein is a multisubunit enzyme complex that transforms chemical energy into motion along microtubules. It plays a wide range of roles in traffic between the endoplasmic reticulum and the Golgi complex and in the transport of membranous organelles. Such transport is essential for chromosome alignment and segregation, for generating and maintaining organelle structure and position, and for facilitating the transfer of material between compartments. The mechanism for assembly into a functional motor is not understood. Moreover there are no high resolution structures for any subunits of dynein. A 10 kDa subunit, here referred to as DLC, is highly conserved among all known dyneins, with 94% sequence identity between Drosophila and human, and is also a component of myosin V. The high conservation suggests a common function of this particular protein in motor complexes of various organisms. The 10 kDa subunit is found to be essential in several cellular processes: embryonic development and oogenesis in Drosophila, nuclear migration in fungus, formation and maintenance of the teguments in the blood fluke, transport of neuronal nitric oxide synthase across axons, and transcriptional regulation during viral infection. The mechanism for these various functions is not known. The purpose of this project is to determine how the structural characteristics of DLC contribute to its multiple regulatory roles. Covalent cross-linking experiments indicate that this polypeptide exists as a dimeric structure within the dynein complex and associates with two other dynein components. The experiments proposed here will focus on using nuclear magnetic resonance spectroscopy to identify the dimer interface, the high resolution structure and dynamics of the dimer, and potential sites of interactions with protein-within the dynein complex and with cargo. Future research is likely to focus on the role of dimerization on the assembly of the complex in vivo, characterization of other subunits of dynein, and their interactions with DLC. The high resolution structure of DLC will not only give clues to its specific and various functions, but more importantly may provide an avenue into structural characterization of the dynein system.