The levels of p53 and Mdm2 are balanced through autoregulatory feedback loops — the RING-finger protein Mdm2 binds to p53 at its transactivation domain and thereby inhibits its transactivation ...

However, loss of p53 tumour-suppressor activity can also occur through amplification of MDM2. As MDM2 is a negative regulator of p53, this promotes p53 degradation and inhibits p53 tumour ...