核孔复合物的结构、组装及功能

Nuclear Pore Complex Structure, Assembly, and Function

核孔复合物(NPC)是一个巨型分子复合物,相对分子质量约125×106。脊椎动物的NPC由大约30种蛋白质组成,这些蛋白质的序列大多具有FG(苯丙氨酸-甘氨酸)重复序列。NPC锚定于双层核膜上,并且是物质跨核膜运输的惟一通道,它可快速介导小分子物质的被动运输以及大分子物质的主动运输过程。虽然NPC具有较大的相对分子质量和复杂的结构,但它可在细胞分裂过程中分离并重新组装。生物大分子经NPC的跨核膜运输直接影响真核细胞的生长、增殖、分化、发育等多种生命活动。本文重点介绍NPC的结构、组装及其功能特点。

The nuclear pore complexes （NPCs） are large （125 MDa） macromolecular complexes that comprise 30 different proteins in vertebrates. These structural elements are termed as nucleoporins and many of them are characterized by FG （phenylalanine-glycine） repeat sequence. NPCs are embedded in the double membrane of the nuclear envelope. It is the unique trafficking machine that can be rapid and accommodates both passive diffusion of relatively small molecules, and active transport of macromolecules. In spite of their size and complex structure, NPCs undergo breakdown and reformation at cell division. The nucleo-cytoplasmic transport pathway of macromolecules affects all aspects of cellular physiology, including gene expression, cell growth, cell proliferation, cell cycle control and cell apoptosis. Outstanding issues involving NPC structure, assembly, and function were reviewed.