Development of a Split SNAP-CLIP Double Labeling System for Tracking Proteins Following Dissociation from Protein–Protein Complexes in Living Cells

The split SNAP-tag protein-fragment complementation assay (PCA) is a useful tool for imaging protein–protein interactions (PPIs) in living cells. In contrast to conventional methods employed for imaging PPIs, the split SNAP-tag PCA enables tracking of proteins following dissociation from protein–protein complexes. A limitation of this system, however, is that it only allows for labeling and tracking of one of the proteins forming the protein–protein complex. To track both proteins forming a protein–protein complex, each protein needs to be appropriately labeled. In this study, a split SNAP-CLIP double labeling system is developed and applied for tracking of each protein forming a protein–protein complex. As a proof-of concept, FM protein for PPIs and protein kinase C alpha (PKCα) for translocation are introduced to a split SNAP-CLIP double labeling system. The results show a split SNAP-CLIP double labeling system enables labeling of both proteins in a protein–protein complex and subsequent tracking of each of the proteins following dissociation from the protein–protein complexes in living cells