MOLECULAR DISSECTION OF THE NUCLEAR-PORE COMPLEX

The nuclear pore complex(NPC) is a similar to 120 megadalton (MDa) sup ramolecular assembly embedded in the double-membraned nuclear envelope (NE) that mediates bidirectional molecular trafficking between the cy toplasm and the nucleus of interphase eukaryotic cells. The structure of the NPC has been studied extensively by electron microscopy (EM), a nd a consensus model of its basic framework has emerged. Over the past few years, there has been significant progress in dissecting the mole cular constituents of the NPC and in identifying distinct NPC subcompl exes. The combination of well-characterized antibodies with different EM specimen preparation methods has allowed localization of several of these proteins within the three-dimensional (3-D) architecture of the NPC. Thus, the molecular dissection of the NPC is definitely on its w ay to being elucidated. Here, we review these findings and discuss the emerging structural concepts.