CRYSTALLOGRAPHIC STUDIES ON NUCLEAR PORE COMPLEX PROTEINS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。核孔复合体(NPC)是真核细胞中最大的大分子复合体之一，在酵母和脊椎动物中分别约为60和125 MDA，由约30种不同的相互作用的蛋白质组成，称为核孔蛋白。核孔围绕其圆柱轴呈八角形对称。它由一个圆柱形核心组成，由八个相互连接的轮辐组成。每个轮辐由Nup93、Nup205和Nup188核孔素组成，并围绕中央通道。这些辐条在核质和细胞质一侧进一步连接到Nup160亚复合体(Nup133、Nup96、Nup107、Nup37、Nup43、Nup160、Nup75)。因此，Nup160复合体形成了一个平行于核包膜的平面伪镜对称。鼻咽癌的中心环进一步与50-100 nm长的纤维相连，这些纤维要么延伸到核质(形成篮状结构)，要么以细胞质细丝的形式进入细胞质。这种复杂的NPC组装在真核细胞生物学中的作用是多种多样的，主要包括：核质扩散转运或主动转运、核周染色质的组织、有丝分裂过程中与动粒的相互作用、基因表达调控、肿瘤发生等。然而，NPC组装是如何控制/调节这些功能的，目前还不完全清楚。我们实验室的研究重点是对NPC组装机制的结构洞察。该项目的主要目标是使这些核孔素单独结晶或与其伙伴形成复合体，并使用X射线结晶学确定其三维结构。这些研究将帮助我们可视化鼻咽癌组装的机制细节，并可能能够假设鼻咽癌的多功能作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The nuclear pore complex (NPC) is one of the largest macromolecular complexes in the eukaryotic cell (approximately 60 MDa and 125 MDa in yeast and vertebrates, respectively), composed of about 30 different interacting proteins named as nucleoporins. The nuclear pore exhibits an octagonal symmetry around its cylindrical axis. It consists of a cylindrical core, composed of eight interconnected spokes. Each spoke is composed of the Nup93, Nup205 and Nup188 nucleoporins, and surrounds the central channel. These spokes are further connected on the nucleoplasm and cytoplasm sides to a Nup160 subcomplex (Nup133, Nup96, Nup107, Nup37, Nup43, Nup160, Nup75). The Nup160 complex hence forms a plane pseudo-mirror symmetry running parallel to the nuclear envelope. The central ring of NPC is further connected to 50-100 nm long fibrils extended either into the nucleoplasm (to form basket like structure) or into cytoplasm as cytoplasmic filaments. The role of such intricate NPC assembly in eukaryotic cell biology is very diverse and mainly includes: nucleo-cytoplasmic transport by either diffusion or active transport, organization of perinuclear chromatin, interactions with kinetochores during mitosis, control of gene expression, oncogenesis etc. However, how these functions are controlled/regulated by NPC assembly is not fully understood. The studies in our lab are focused to gain the structural insights into the mechanism of NPC assembly. The major goal of the project is to crystallize these nucleoporins either individually or in complex with their partners and determine its 3D structure using X-ray crystallography. These studies will help us to visualize the mechanistic details of NPC assembly and might be able to postulate hypothesis for versatile role of the NPC.