p53-induced death domain-containing protein 1 is a protein in humans that is encoded by PIDD1 gene. Promotes apoptosis downstream of the tumor suppressor as component of the DNA damage/stress response pathway that connects p53/TP53 to apoptosis. 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. Associates with CASP2/caspase-2 and CRADD/RAIDD, and induces activation of CASP2 which an important regulator in apoptotic pathways.