Figure 5.

Schematic overview of the p53/p73 isoform interactions mediating transactivation. (A) The p53/p73 isoforms form homotetramers to transactivate target genes; (B) certain p53/p73 isoforms can form heterotetramers and consequently antagonize p53/TAp73 transactivation ability or (C) compete with p53/TAp73 for the same promoter sequences, thus exerting a dominant-negative effect; (D) p53β can modulate the promoter activity of target genes (e.g., BAX) only in the presence of p53α; (E) the p53 isoforms can independently mediate transactivation; (F) the p53 isoforms cooperate with the other family members, e.g., p73, to mediate transactivation. Adapted from [14,120,277].