Poly(ADP-ribose) polymerase 1; Poly(ADP-ribose) polymerase 2 (PARP1; PARP2)

Poly(ADP-ribose) polymerase 1 (PARP1) and Poly(ADP-ribose) polymerase 2 (PARP2) are nuclear enzymes that detect and initiate cellular responses to single-strand DNA breaks by synthesizing poly(ADP-ribose) chains from NAD+, facilitating DNA repair and maintaining genomic stability. They also regulate transcription, chromatin structure, cell death mechanisms, inflammation, metabolism, and other biological functions. Both enzymes are crucial in cancer biology, and inhibitors selectively exploit defects in DNA repair pathways, notably in BRCA-mutated tumors. Both are established therapeutic targets in oncology with several clinically approved inhibitor drugs.

Other names

NAD+ ADP-ribosyltransferase 1Poly[ADP-ribose] synthase 1ADPRT1PARP2

Inhibitors block PARP enzymatic activity, leading to accumulation of DNA damage and selective tumor cell death—often via synthetic lethality in DNA repair-deficient cancers, especially those with BRCA1/2 mutations.