Currently, much research focuses
on dissecting the specific contributions of each class of
isoforms to the functions of p63. Although there is still no
definitive evidence regarding the mechanistic role of each
isoform, several lines of evidence indicate that TAp63 isoforms
can induce apoptosis and senescence, ΔNp63 proteins
can promote cell survival and proliferation, and both
kinds of isoforms are involved in cancer formation and
progression. Indeed, both TAp63 and ΔNp63 have been
described as metastasis inhibitors, albeit via different mechanisms.
Moreover, the ratio between the two major classes
of isoforms, as well as their interactions with other p53
family members, plays an important role in cancer formation
and progression. Clearly, TAp63 and ΔNp63 have distinct
and overlapping functions in normal and cancer tissues.
Here, we discuss functions known to be specific to TAp63
versus ΔNp63. Whenever possible, we make a distinction
between isoforms with different C-termini, but unfortunately
the functional differences between these isoforms are still
largely unknown.