TIE-UP-SIN: A Method for Enhanced Identification of Protein-Protein Interactions.

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Protein-protein interactions (PPIs) are crucial for cellular functions but challenging to identify in vivo.
• Existing methods struggle to capture transient or weak interactions under native conditions.

Purpose of the Study:

• To present TIE-UP-SIN, a novel method for in vivo identification and quantification of PPIs in bacterial systems.
• To enable robust capture and quantification of transient and weak protein interactions.

Main Methods:

• Combines ¹⁵N metabolic labeling, reversible formaldehyde crosslinking, affinity purification, and quantitative mass spectrometry.
• Utilizes a triple-sample design (WT/WT, bait/WT, bait/bait) for specific interactor identification.
• Employs a user-friendly web application for automated data analysis, normalization, and visualization.

Main Results:

• TIE-UP-SIN effectively preserves transient and weak PPIs during purification.
• Internal ¹⁵N labeling ensures robust quantification and reduces experimental variability.
• The triple-sample design accurately distinguishes specific from nonspecific interactors.

Conclusions:

• TIE-UP-SIN is a robust and adaptable method for identifying and quantifying PPIs in diverse bacterial systems.
• The method simplifies complex data analysis through an automated web application.
• This approach enhances the study of bacterial cellular physiology by revealing critical protein interactions.