Nucleocytoplasmic transport enters the atomic age.

Nucleocytoplasmic transport occurs through nuclear pore complexes (NPCs) and is mediated by saturable transport receptors that shuttle between the nucleus and cytoplasm. Our understanding of the molecular interactions underlying this process has improved dramatically as a result of the elucidation of the crystal structures of several nuclear transport factors either alone or in a complex with other components of the nuclear transport machinery. Furthermore, a conserved family of proteins, which is distinct from the well characterized family of importin beta-like nuclear export receptors, is implicated in the export of messenger RNA to the cytoplasm.