Structure of the cytoplasmic ring of the Xenopus laevis nuclear pore complex

Abstract

The nuclear pore complex (NPC) mediates nucleocytoplasmic cargo transport. Here, we present a single-particle cryo–electron microscopy reconstruction of the cytoplasmic ring (CR) subunit from the Xenopus laevis NPC at 3.7- to 4.7-angstrom resolution. The structure of an amino-terminal domain of Nup358 has been resolved at 3.0 angstroms, facilitating the identification of five Nup358 molecules in each CR subunit. Our final model of the CR subunit included five Nup358, two Nup205, and two Nup93 molecules in addition to the two previously characterized Y complexes. The carboxyl-terminal fragment of Nup160 served as an organizing center at the vertex of each Y complex. Structural analysis revealed how Nup93, Nup205, and Nup358 facilitate and strengthen the assembly of the CR scaffold that is primarily formed by two layers of Y complexes.