Figure 1.

Structure of the nuclear pore complex. (A) Schematic diagram of the nuclear pore complex (NPC). The complex has a vertical eightfold symmetry. The nuclear and cytoplasmic sides differ from each other in that the nuclear basket projects into the nucleoplasm and eight filaments extend into the cytoplasm. (B) Field-emission scanning electron microscopy shows the surface structure of the cytoplasmic (a) and nucleoplasmic (b) faces of the NPC. The micrographs were kindly provided by M. Goldberg.