Fig. 4. Docking of NUP358^NTD on the cytoplasmic face of the NPC.

(A) Overview of the NPC cytoplasmic face with isosurface rendering of unexplained density clusters I (red) and II (cyan) of the ~12Å cryo-ET map of the intact human NPC. The inset indicates the location of the magnified view showing cartoon representations of five copies of NUP358^NTD docked in unassigned density cluster I. (B) Comparison of the binding of two NUP358^NTD copies (cartoon) to distal and proximal CNCs (surface). (C-E) Architecture of the pentameric NUP358^NTD bundle attachment site on a cytoplasmic outer ring spoke with cartoon- and surface-represented structures (left) and schematics (right), sequentially illustrating the placement of (C) four copies of NUP358^NTD around NUP96 and NUP107 interfaces on the stalks of tandem-arranged Y-shaped CNCs, (D) a distal copy of NUP93^SOL collocated at the center of the NUP358^NTD bundle, interfacing with both proximal and distal CNC stalks, and (E) the NUP358^NTD dome copy interfacing with the stalk-attached NUP358^NTD quartet beneath. (F) Overview of the entire cytoplasmic face of the NPC in cartoon representation and as schematic, illustrating the distribution of 40 NUP358^NTD copies anchored as pentameric bundles across the eight NPC spokes. (G) Schematic of NUP358 attachment to the cytoplasmic outer ring spoke. The NUP358 pentameric bundle is linked together by interactions between oligomerization elements (OEs). Anchored by NUP358^NTD, the rest of NUP358 domains are linked by unstructured linker sequences and are expected to freely project from the cytoplasmic face of the NPC. Distal and proximal positions are labeled according to the legend in (A).