ADP-ribose (ADPr): Synthesized by
PARPs and removed by ADPr Hydrolases
ADPr is a signaling molecule that is synthesized by PARP proteins onto the proteins they modify. Its importance in cancer has already been demonstrated by the success of PARP1 inhibitors used in the clinic for the treatment of multiple cancers. ADPr Hydrolases play an equally important role in ADPr signaling by removing ADPr from proteins modified by PARPs. The addition and removal of ADPr from proteins results in significant changes in cellular signaling including cancer relevant cellular stress responses.

- PARPs ADP-ribosylate target proteins, including cellular stress proteins, altering their function
- ADPr Hydrolases remove ADPr from modified proteins which also changes protein function
- ADPr synthesis and ADPr hydrolysis often play parallel and non-opposing roles in the same cellular stress responses
