Poly(ADP-ribose) polymerase 3 (PARP3) is an important member of the PARP family and shares high structural similarities with both PARP1 and PARP2. Poly(ADP-ribose) polymerase 3 (PARP3), a critical player in cellular response to DNA double-strand breaks (DSBs), plays an essential role in the maintenance of genome integrity. The ADP ribosyl transferase [poly(ADP-ribose) polymerase] ARTD3(PARP3) is a newly characterized member of the ARTD(PARP) family that catalyzes the reaction of ADP ribosylation, a key posttranslational modification of proteins involved in different signaling pathways from DNA damage to energy metabolism and organismal memory.

AIF1, also known as IBA1, is an actin-binding protein. AIF1 is expressed selectively in human macrophage-like cell lines, and in a subset of CD68(+) macrophages in the interstitial and perivascular spaces of human heart allografts. It is expressed in macrophages and neutrophils. AIF1 enhances membrane ruffling and RAC activation. AIF1 enhances the actin-bundling activity of LCP1. It also enhances lymphocyte migration. AIF1 may play a role in macrophage activation and function. It binds calcium and plays a role in RAC signaling and in phagocytosis. It promotes the proliferation of vascular smooth muscle cells and of T-lymphocytes.