Method Development

MAC-tag

AP-MS allows placing a protein of interest (POI, bait) into functional context to study its partner proteins. It has been successfully implemented for identifying soluble/stable protein complexes in a high-throughput manner. The recently developed proximity-labeling approaches, such as BioID, have become a complementary method to address the limitation of the AP-MS. The BioID technique is based on a mutant form of biotin protein ligase (BPLs, Escherichia coli BirA R118G, BirA*) fused with a POI to promiscuously biotinylate proximal proteins.

We are developing an integrated approach named MAC (Multiple Approaches Combined) –tag system, which utilizes both AP-MS and BioID in a single construct to parallel explore the protein interactome. Moreover, application of the MAC-tag system on subcellular localization markers provided a proximity cellular protein landscape, which serves as a reference grid to probe the POI’s  molecular level distribution. To facilitate the use of the MAC-tag system, we constructed the online MAC-tag platform for data analysis and processing.

References:

An AP-MS- and BioID-compatible MAC-tag enables comprehensive mapping of protein interactions and subcellular localizations.
Nat Commun. 2018 Mar 22;9(1):1188. DOI

Combined proximity labeling and affinity purification-mass spectrometry workflow for mapping and visualizing protein interaction networks.
Nat Protoc. 2020 Aug 10. DOI