Table 1 Comparison of p53, p63, and p73 function and regulation

The data summarize the similarities and differences between p53 and the newer p53 family members. Unless otherwise specified, this table only refers to the full-length, transactivation-competent isoforms.

p53 p63 p73

Transactivation + + +a
Apoptosis + + +b
DNA damage induction + +/- +/-
Activation by oncogenes (E2F) + - +
Viral oncoprotein binding + - -c
MDM-2-mediated degradation + - -
Cancer mutations + - -
Role in development - + +

a For some forms: certain {Delta}Np63 and {Delta}Np73 forms do not transcriptionally activate p53-responsive genes and

b For some forms: do not induce apoptosis. Instead, the {Delta}N forms block the ability of the corresponding full-length proteins to transactivate target genes and induce apoptosis.

c Most viral oncoproteins do not bind p73. HTLV-tax, and possibly E4orf6, are exceptions (see text).