Figure 1. The structure of the native X. laevis NPC.

(a,b) Surface-rendered grazing views of the NPC. The NE is depicted in grey, the luminal densities in yellow12, and the SR in blue. (a) Upper side of the CPR is shown in golden colour. (b) Top of the NPR is shown in green colour. (c) View of the central nucleocytoplasmic section (25-nm thick) through the NPC structure; CCR (A) and SR-CCR interface (B). Extended linker structures protrude from the NPR (C and D), as well as from the CPR (E). The putative position of the Nup214/Nup88 complexes14,27 is denoted by F. Suggested nuclear transport routes passing through NPC barrier, illustrated as solid and dashed curves. The axes show the dimensions of the NPC in the x- and y-direction.