NanoBRET® Target Engagement (TE) is a biophysical method of assessing the binding between a compound and a target protein in live cells. Based on bioluminescent resonance energy transfer (BRET), NanoBRET® TE can be applied to multiple classes of target proteins, including poly (ADP-ribose) glycohydrolase (PARG) and members of the poly (ADP-ribose) polymerase (PARP) family, which play critical roles in cellular processes such as transcription, cell division and DNA repair.