In situ structural analysis of the human nuclear pore complex

Area of Science:

• Cell biology
• Structural biology
• Biochemistry

Background:

• Nuclear pore complexes (NPCs) are essential for eukaryotic cell function, regulating nucleocytoplasmic transport.
• NPCs are large, multi-megadalton structures composed of numerous proteins called nucleoporins (Nups).
• Understanding the in situ architecture of NPCs, particularly the Y and inner-ring complexes, remains a challenge.

Purpose of the Study:

• To generate a comprehensive architectural model of the human nuclear pore complex.
• To elucidate the in situ oligomerization of the Y complex and its interactions with other NPC components.
• To investigate the role of specific nucleoporins, such as Nup358, in NPC assembly.

Main Methods:

• Cryo-electron tomography
• Mass spectrometry
• Biochemical analysis
• Perturbation experiments
• Structural modeling

Main Results:

• A detailed architectural model of the human NPC was generated.
• Previously unknown protein interfaces within Y complexes and with inner-ring complexes were identified.
• The nucleoporin Nup358 (Ranbp2) was found to play a critical role in Y-complex oligomerization.
• Established distinctions between scaffold and transport-channel nucleoporins were challenged.

Conclusions:

• The study provides the most comprehensive architectural model of the human NPC to date.
• NPC assembly involves complex protein-protein interactions, including unexpected roles for certain nucleoporins.
• Functional and structural heterogeneity exists within seemingly identical NPC building blocks.