Split protein biosensor assays in molecular pharmacological studies.

Cellular signalling is commonly mediated through dynamic protein-protein interactions (PPIs). When pivotal PPIs are deregulated, cellular signalling can be altered; it is therefore attractive to monitor regulated PPIs to understand their role in health and disease. Genetically encoded biosensors that rely on protein fragment complementation have made it feasible to monitor PPIs in living cells precisely and robustly. In particular, split protein biosensors using fluorescent proteins or luciferases are frequently applied. Further, split TEV and split ubiquitin biosensor platforms flexibly allow using readouts of choice, including transcriptional barcode reporters that are amenable to multiplexed high-throughput formats and next-generation sequencing. Combining these technologies will enable assessing drug target activities and cellular response profiles in parallel, thereby opening up new avenues in drug discovery.