p53-dependent Damage-Inducible Nuclear Protein 1 (p53DINP1 protein) is a p53-induced nuclear protein that induces p53-dependent apoptosis by regulating p53 function through Ser 46 phosphorylation. A DNA encoding p53DINP1 can be applied as anticancer agents for destroying neoplasms such as tumors, and as therapeutic or preventive agents for diseases associated with p53-mediated apoptosis abnormalities. It is also possible to apply the above protein and DNA in methods of screening for candidate compounds for regulating p53-mediated apoptosis.