PARG Background Information The synthesis and rapid turnover of ADP-ribose polymers is an immediate cellular response to DNA damage. Poly (ADP-ribose) is a reversible covalent-modifier to chromosomal proteins and is synthesized by poly (ADP-ribose) polymerase (PARP-1) and other related enzymes. Poly (ADP-ribose) glycohydrolase (PARG) is the enzyme responsible for polymer turnover. Under normal growth conditions, PARG localizes to the cytoplasm. PARG is an enzymatically active protein that is cleaved to multiple fragments. PARG is cleaved during etoposide-, staurosporine-, and Fas-induced apoptosis in human cells by caspases, and generates two C-terminal fragments, which still contain the active site of the enzyme required to hydrolyze poly (ADP-ribose). Under normal growth, PARG is expressed only as a doublet by SDS-PAGE. The gene encoding PARG maps to human chromosome 10q11.23.
