Nuclear Pore Complex Structure and Dynamics Revealed by Cryoelectron Tomography

TLDR

Nuclear pore complexes (NPCs) are gateways for nucleocytoplasmic exchange. The study analyzes NPC structure in a near‑physiological state by cryoelectron tomography of transport‑active, intact Dictyostelium nuclei. NPC subvolumes were extracted from tomograms and classified and averaged in silico to reveal distinct structural states. The central plug/transporter varied in volume and position along the nucleocytoplasmic axis, indicating it functions as cargo in transit, and its movement was coupled to scaffold rearrangements.

Abstract

Nuclear pore complexes (NPCs) are gateways for nucleocytoplasmic exchange. To analyze their structure in a close-to-life state, we studied transport-active, intact nuclei from Dictyostelium discoideum by means of cryoelectron tomography. Subvolumes of the tomograms containing individual NPCs were extracted in silico and subjected to three-dimensional classification and averaging, whereby distinct structural states were observed. The central plug/transporter (CP/T) was variable in volume and could occupy different positions along the nucleocytoplasmic axis, which supports the notion that it essentially represents cargo in transit. Changes in the position of the CP/T were accompanied by structural rearrangements in the NPC scaffold.