The Role of Poly(ADP-Ribose) Polymerase-1 (PARP-1) Activation in Focal Cerebral Ischemia

Poly(ADP-ribosyl)ation is the post-translational modification of proteins operated by poly(ADP-ribose) polymerases (PARPs). PARPs are enzymes that are able to catalyze the transfer of ADP-ribose units from nicotinamide adenine dinucleotide (NAD) to target proteins and are particularly abundant in cell nuclei, where they play a key role in the maintenance of homeostasis. Poly(ADP-ribosyl)ation significantly affects protein functioning because of the high negative charge and steric hindrance conferred by the chains of poly(ADP-ribose) (PAR). PARP-1 is the founding member and the most commonly studied of these enzymes and shows the highest poly(ADP-ribosyl)ating activity. Sequences encoding novel PARPs have been identified and, overall, the PARP superfamily is a growing family of enzymes with numerous members with roles that are yet to be identified (Ame et al. 2004; Smith 2001).