Toward a Molecular Understanding of the Structure and Function of the Nuclear Pore Complex

Abstract

Molecular trafficking between the nucleus and cytoplasm of interphase cells occurs via the nuclear pore complexes (NPCs), ∼120-MDa supramolecular assemblies embedded in the double-membraned nuclear envelope. Significant progress has been made in elucidating the 3-D architecture of the NPC, and in identifying and characterizing NPC proteins, and cloning and sequencing their genes. Several of these proteins have now been localized within the 3-D structure of the NPC. Over the past few years there have also been some advances in establishing the signals, receptors, and factors mediating import of nuclear proteins and snRNP particles, and nuclear export of RNAs and RNP particles. Nevertheless, relatively little is known about the molecular mechanisms underlying nucleocytoplasmic transport through the NPC. Here we review recent advances toward the 3-D structure and molecular architecture of the NPC, and the molecular basis of nucleocytoplasmic transport of proteins, RNAs, and RNP particles through the NPC.