Biology of Poly(ADP-Ribose) Polymerases: The Factotums of Cell Maintenance

The protein family of poly(ADP-ribose) polymerases (PARPs) or diphtheria toxin-type ADP-ribose transferases (ARTDs) are multidomain proteins originally identified as DNA repair factors. There are 17 PARP enzymes in humans, and it is now evident that PARPs undertake more tasks than DNA repair. The aim of this review is to give a comprehensive view of the biological roles of the PARP family starting from the simplest biochemical reactions to complex regulatory circuits. Special attention will be laid on discussing linkage of PARP enzymes with tumor biology, oxidative stress, inflammatory, and metabolic diseases. A better understanding of PARP-mediated processes and pathologies may help in identifying new pathways and, by these, new targets to combat diseases that affect large populations and seriously shorten life expectancy and the quality of life, such as cancer, metabolic, or inflammatory diseases.