Proximity Labeling Proteomics

Proximity-labeling proteomics has become a trendy new tool in studying protein-protein interactions. It utilizes the physical proximity between proteins in the cell to make predictions about direct interactions. The original BioID, as well as its improved successor the BioID2, technique are based on a promiscuous bacterial biotin ligase (BirA* R118G, or simply BioID) which is fused to a bait protein to generate a history of protein-protein associations over time in living cells by simply biotinylating primary amines on proximal proteins within as little as a 10nm radius. BioID offers a number of advantages over traditional affinity labelling proteomics, such as the detection of weaker or transient interactions, its utility in studying insoluble proteins and obviously the strength of the biotin-streptavidin bond allowing for very specific pull downs.