Near-atomic Structure of the Cytoplasmic Ring of the Xenopus laevis Nuclear Pore Complex

The nuclear pore complex (NPC) mediates nucleocytoplasmic shuttling. Here we present single-particle cryo-EM structure of the cytoplasmic ring (CR) from the Xenopus laevis NPC at 4.1-4.7 [A] resolutions. The structure of an N-terminal domain of Nup358 was resolved at 3.0 [A], facilitating identification of five Nup358 molecules in each CR subunit. Aside from unveiling the assembly details of the two Y-shaped multicomponent complexes (Y complexes) in each CR subunit, the improved resolutions reveal the C-terminal fragment of Nup160 to be an organizing center at the vertex of each Y complex. Our structures show that the scaffold of a CR subunit comprises five Nup358, two Nup205 and two Nup93 molecules in addition to the previously characterized Y complexes. One-Sentence SummaryImproved resolutions of the cytoplasmic ring (CR) of the Xenopus laevis nuclear pore complex reveal that five Nup358 molecules, together with two copies of interweaved Nup205, Nup93 and Y complexes, constitute the scaffold of each CR subunit.