A genetically-encoded photo-proximity labeling approach for mapping protein territories

we introduce a genetically encoded system that allows protein interactomes to be captured using brief exposure to visible light. Our approach, Light-induced Interactome Tagging (LITag), involves fusing an engineered version of a plant flavoprotein (~12 kDa) to a protein of interest. Blue light excitation of the flavin mononucleotide (FMN) cofactor within the fusion protein leads to local generation of reactive radical species within exogenously added cell-permeable probes. When combined with quantitative proteomics, the system generates ‘snapshots’ of protein interactions with a temporal resolution of a few seconds.