Using Cryo-EM to Study the Structure of COPII Coats

描述（由申请人提供）： 该提案的目标是使用冷冻电子显微镜进行COPII包被囊泡的三维重建。COPII蛋白负责形成将蛋白质和脂质从内质网（ER）运输到高尔基体的囊泡。COPII蛋白由Sar 1、Sec 23/24和Sec 13/31组成。这些在ER膜上形成晶格，使膜内陷成球形囊泡。生物化学实验已经提出了蛋白质相互作用的方式，并导致了许多COPII晶格形成的模型。COPII晶格的结构将通过低温电子显微镜进行研究。解析了Sar 1和Sec 23/24的晶体结构。将这些结构拟合到COPII涂层的重建中将有助于确定COPII晶格中的蛋白质间接触以及晶格是如何形成的。此外，这些研究将有助于了解真核蛋白质转运机制，并可能有助于理解和治疗与运输中断相关的疾病。

DESCRIPTION (provided by applicant): The goal of this proposal is to use cryo-electron microscopy to make three-dimensional reconstructions of COPII coated vesicles. COPII proteins are responsible for forming the vesicles that transport proteins and lipids from the endoplasmic reticulum (ER) to the Golgi apparatus. COPII proteins consist of Sar1, Sec23/24, and Sec13/31. These form a lattice on the ER membrane that invaginates the membrane into a spherical vesicle. Biochemical experiments have suggested ways that the proteins interact and have lead to a number of models for the formation of the COPII lattice. The structure of the COPII lattice will be studied by cryoelectron microscopy. Crystal structures of Sar1 and Sec23/24 have been solved. Fitting these structures into the reconstruction of the COPII coat will help determine the inter-protein contacts in the COPII lattice and how the lattice is formed. Moreover, these studies will contribute to the understanding of eukaryotic protein transport machinery and may contribute to the understanding and treatment of diseases associated with disrupted transport.