Role of Poly(ADP-Ribose) Polymerase in Apoptosis
Poly(ADP-ribose) polymerase (PARP) is a DNA break sensor enzyme synthesizing a homopolymer of ADP-ribose in response to DNA damage. The enzyme possesses three functional domains. The 43-kDa N-terminal fragment contains the two zinc fingers responsible for the DNA-binding function of the enzyme and a bipartite nuclear localization signal. The central 16-kDa fragment contains the automodification domain as well as a putative leucine zipper, and the catalytic domain is included in the 55-kDa C-terminal portion of the protein.