Photoactivated In Vivo Proximity Labeling

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Understanding cellular function relies on identifying molecular interactions.
• Existing methods like co-purification struggle with low-affinity interactions and difficult-to-solubilize proteins.
• These limitations hinder comprehensive analysis of cellular machinery.

Purpose of the Study:

• To present experimental protocols for in vivo proximity labeling (IPL).
• To enable the discovery of novel protein-protein and protein-RNA interactions.
• To overcome limitations of traditional interaction identification techniques.

Main Methods:

• In vivo proximity labeling (IPL) utilizes a heterobifunctional probe and a monomeric streptavidin tag.
• The probe is recruited to a protein of interest, and UV irradiation triggers covalent biotinylation of proximal molecules.
• Biotinylated proteins and RNAs are subsequently recovered using biotin affinity capture.

Main Results:

• IPL allows for covalent tagging of proteins and RNAs based on proximity within living cells.
• This technique offers tight spatial and temporal control over labeling.
• Novel protein-protein and protein-RNA interactions can be discovered.

Conclusions:

• In vivo proximity labeling is a powerful technique for identifying molecular interactions.
• IPL overcomes limitations of co-purification methods, particularly for low-affinity interactions and challenging cellular compartments.
• The described protocols facilitate the discovery of novel biological interactions.