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 (By similarity). Possesses a tumor suppressing activity in glioma cells. Homodimer. Interacts with SIAH1A and SIAH2. Interacts with TRAF2 (By similarity). Brain, glial cells, astrocytes, embryo, placenta, testis, ovary and uterus. In the placenta it is found in the layer of villous cytotrophoblast cells while in the ovary it is found in the cells of the ovarian stroma including the thecal layers around the follicles. Expression is highly repressed in glioma cell lines. 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.