Induces apoptosis in cooperation with SIAH1A. Acts as a mediator between p53/TP53 and BAX in a neuronal death pathway that is activated by DNA damage. Acts synergistically with TRAF2 and inhibits TNF induced apoptosis through activation of NF-kappa-B. Plays a role in regulating maternal behavior and offspring growth. Homodimer. Interacts with SIAH1A and SIAH2. Interacts with TRAF2. Brain, glial cells, neurons, skeletal muscle, uterus and placenta. In the placenta it found in all trophoblast cells. Strongly expressed upon gastrulation and subsequently becomes restricted to skeletal muscle and subregions of the CNS. At 9.5 dpc, expressed in the branchial arches, somites and gut but little in the heart and neural tissues. At 12.5 dpc strongly expressed in the cranial skeleton, tongue, vertebral cartilage, pituitary and the luminal epithelium. Induced during p53/TP53 mediated apoptosis. Up-regulated by DNA damage in cortical neurons in the presence of p53/TP53. The SCAN domain enables PEG3 homo- or heterodimerization to control gene expression in a combinatorial fashion. Belongs to the krueppel C2H2-type zinc-finger protein family.