Acts as a tumor suppressor in many tumor types; induces growth arrest or apoptosis depending on the physiological circumstances and cell type. Involved in cell cycle regulation as a trans-activator that acts to negatively regulate cell division by controlling a set of genes required for this process. One of the activated genes is an inhibitor of cyclin-dependent kinases. Apoptosis induction seems to be mediated either by stimulation of bax and fas antigen expression, or by repression of Bcl-2 expression. Binds 1 zinc ion per subunit. Binds DNA as a homotetramer. In double morpholino knockdown of tp53 and yju2, tp53 deficiency rescues animals from developmental neurodegeneration observed on yju2 mutants and radiosensitivity. Belongs to the p53 family.