Not counting histones, PARP1 [Poly(ADP-ribose) Polymerase 1] is the most abundant nuclear protein in mammalian cells. While principally known for its role in various types of DNA repair, recent work expanded it’s repertoire to include genome stability maintenance, chromatin remodeling, DNA methylation/gene expression, cellular differentiation, and cell survival modulation via NAD+/ATP regulation.1 It performs Poly(ADP-ribosyl)ation