PIDD promotes apoptosis downstream of the tumor suppressor as component of the DNA damage/stress response pathway that connects p53/TP53 to apoptosis. It associates with NEMO/IKBKG and RIP1 and enhances sumoylation and ubiquitination of NEMO/IKBKG which is important for activation of the transcription factor NF-kappa-B. It associates with caspase-2 and RAIDD, and induces activation of caspase-2 which is an important regulator in the apoptotic pathways.