May play a significant role in p53/TP53-mediating signaling pathway. Interacts with p53/TP53. Cell cycle dependent intracellular localization. Highly expressed in heart, brain and small intestine. Less abundant in skeletal muscle, spleen, prostate, ovary and colon. A smaller transcript is expressed specifically in the testis. By p53/TP53, UV irradiation, by hydrogen peroxide treatment or by treatment with a DNA-damaging reagent.