Cryo-EM structure of the nuclear ring from Xenopus laevis nuclear pore complex

Xiechao Zhan,Minhao Liu,Chuangye Yan,Pan Wang,Qinghua Tao,Qifan Wang,Jianlin Lei,Yanyu Zhao,Chao Zeng,Gaoxingyu Huang,Ke Liang,Xuechen Zhu,Yigong Shi,Qiang Zhou

doi:10.1038/s41422-021-00610-w

Xiechao Zhan, Minhao Liu

Open Access

https://doi.org/10.1038/s41422-021-00610-w

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Abstract

Nuclear pore complex (NPC) shuttles cargo across the nuclear envelope. Here we present single-particle cryo-EM structure of the nuclear ring (NR) subunit from Xenopus laevis NPC at an average resolution of 5.6 Å. The NR subunit comprises two 10-membered Y complexes, each with the nucleoporin ELYS closely associating with Nup160 and Nup37 of the long arm. Unlike the cytoplasmic ring (CR) or inner ring (IR), the NR subunit contains only one molecule each of Nup205 and Nup93. Nup205 binds both arms of the Y complexes and interacts with the stem of inner Y complex from the neighboring subunit. Nup93 connects the stems of inner and outer Y complexes within the same NR subunit, and places its N-terminal extended helix into the axial groove of Nup205 from the neighboring subunit. Together with other structural information, we have generated a composite atomic model of the central ring scaffold that includes the NR, IR, and CR. The IR is connected to the two outer rings mainly through Nup155. This model facilitates functional understanding of vertebrate NPC.

Highlights

IntroductionNuclear pore complex (NPC) constitutes the only regular route of cargo transport between the cytoplasm and the nucleus.[1,2] NPC resides on the nuclear envelope (NE) of all eukaryotic cells
Using data at the bin-2 level, we generated a reconstruction of the nuclear ring (NR) subunit, which after auto-refinement
We report the reconstruction of the NR subunit at an average resolution of 5.6 Å (Fig. 1; Supplementary information, Table subunit 1 (S1))

Summary

Introduction

Nuclear pore complex (NPC) constitutes the only regular route of cargo transport between the cytoplasm and the nucleus.[1,2] NPC resides on the nuclear envelope (NE) of all eukaryotic cells. The size and composition of the NPC may vary across species,[3,4,5,6,7] the overall organization is conserved among all eukaryotes.[2,8,9,10] The vertebrate NPC, with a combined molecular mass of over 100 MDa,[11,12,13] consists of three central ring scaffolds that collectively define the central pore: cytoplasmic ring (CR), inner ring (IR), and nuclear ring (NR)[4,9,14,15] (Fig. 1a). IR in the center of the NPC is sandwiched by two outer rings (CR and NR) and displays a twofold symmetry.[16,17]

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