Capturing molecular handshakes: PhIX-MS reveals transient interactions that control the proteasome complex

Area of Science:

• Structural biology
• Molecular cell biology
• Biochemistry

Background:

• Capturing transient and low-affinity protein interactions in their native cellular environment remains a significant challenge in structural biology.
• Understanding these interactions is crucial for elucidating cellular mechanisms and disease pathways.

Purpose of the Study:

• To develop and validate a novel approach for capturing low-affinity protein interactions in vivo.
• To integrate these interaction restraints with advanced computational and imaging techniques for structural determination.

Main Methods:

• The study employed a method to capture weak protein-protein interactions within living cells.
• The obtained structural restraints were integrated with cryoelectron microscopy (cryo-EM) data.
• Computational modeling using AlphaFold was utilized to refine and localize interactors.

Main Results:

• The integrated approach successfully localized dynamic interactors on native human proteasomes.
• The method demonstrated sensitivity in capturing low-affinity interactions that are often missed by traditional techniques.
• High-resolution structural insights into proteasome complexes were achieved.

Conclusions:

• This work presents a powerful strategy for studying dynamic protein interactions in complex cellular systems.
• The findings advance our ability to map the interactome and understand the structural basis of cellular regulation.
• The combined approach offers a significant step forward in structural biology for analyzing transient molecular assemblies.