Three-dimensional architecture of the isolated yeast nuclear pore complex: functional and evolutionary implications

Area of Science:

• Cell Biology
• Structural Biology
• Biochemistry

Background:

• The nuclear pore complex (NPC) is a crucial gatekeeper regulating molecular traffic between the nucleus and cytoplasm.
• Understanding NPC structure is vital for deciphering cellular processes and disease mechanisms.
• Previous studies have provided insights into vertebrate NPC architecture, but direct comparisons with yeast are limited.

Purpose of the Study:

• To determine the three-dimensional structure of the yeast nuclear pore complex (yNPC).
• To enable a direct structural comparison between yeast and vertebrate NPCs.
• To identify conserved and divergent features of NPC architecture.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was used to image frozen-hydrated yeast nuclear pore complexes.
• Computational reconstruction methods were applied to generate a 3D map of the yNPC.
• Comparative analysis was performed between the yNPC map and existing vertebrate NPC structures.

Main Results:

• A detailed 3D map of the yNPC was generated, revealing an octagonal inner spoke ring anchored by a novel membrane-interacting ring.
• A central cylindrical transporter with variable radial expansion, potentially involved in gating, was identified.
• Key components, including the inner spoke ring, transmembrane spoke domain, and transporter, are conserved between yeast and vertebrates.

Conclusions:

• The yeast NPC shares fundamental structural elements with the vertebrate NPC, highlighting their conserved roles in nuclear transport.
• Evolutionary divergence in NPC architecture may be linked to variations in nuclear transport regulation and mitotic processes.
• These findings provide a structural basis for understanding NPC function and evolution across eukaryotes.