Live-Cell Imaging of the Binding between a Chemical Drug and Its Target Proteins Based on Intracellular Redistribution of the Target Proteins

In modern pharmacology, obtaining an in-depth understanding of the interaction of chemical drugs with their target proteins is essential for drug discovery and the advancement of precision medicine. However, detecting these drug–protein interactions in living cells remains challenging owing to the lack of reliable methodologies. The current study presents a robust strategy involving the redistribution of target proteins in cells and applying a cotranslocation-based cellular assay for monitoring drug–target interactions in living cells. This technique utilizes an enhanced green fluorescent protein (EGFP)-tagged drug target protein that is translocated from the cytoplasm to the plasma membrane when exposed to a biotin-conjugated drug and phorbol 12-myristate 13-acetate (PMA). This movement is facilitated by the membrane-translocation properties of the C1A–mRFP–streptavidin fusion protein, which anchors the biotinylated small-molecule drug and facilitates the spatial redistribution of its target proteins. This system provides a dynamic tool for the real-time observations of drug–protein binding events within cellular environments.