Characterizing drug activity with sensitive interactomes in human living cells
A number of human diseases results from abnormal protein-protein interactions (PPIs) involving key regulatory proteins. Therefore, an important strategy in therapeutics consists in developing inhibitory molecules that should ideally be specific for the aberrant PPI. In this context, it is critical to evaluate the number of PPIs that could be affected by the candidate molecule and to analyze the inhibitory potential before and after the formation of the PPI. Surprisingly, these two molecular aspects are rarely considered, due to a lack of appropriate methodological approaches. In this study, we present a novel methodology that captures drug-sensitive PPIs by considering drug-induced cellular functions in live cell conditions. As a proof-of-concept, we identified interactions of the human core signaling protein ERK1 that are specifically affected by two different inhibitory molecules. In addition, we used a complementary set of innovative tools that allowed visualizing the inhibitory effect on ERK1/cofactor protein complexes after their assembly in living cells. Overall, our work establishes a unique methodological approach for deciphering drug activity for potentially any target bait protein of interest.