The DBD and OD are shared by all isoforms
and are 60 % and 37 % homologous to those of p53,
respectively.The p63α and p63β isoforms contain
an additional TA domain (TA2) encoded in exons 11 and 12,
which may be responsible for mediating ΔNp63α and
ΔNp63β transactivation activity. Further, TAp63α
and ΔNp63α contain two more C-terminal domains, namely
a Sterile Alpha Motif (SAM) and a Post-Inhibitory Domain
(PID). The SAM domain consists of five tightly
packed alpha helices, and it is important for proteinprotein
interactions, presumably with other SAM domaincontaining
proteins.The PID binds to the TA domain of
TAp63 isoforms, thus inhibiting gene transactivation and
regulating TAp63 activity