The transcriptional co-activator p300 has been reported to regulate the tumor suppressor
p53 and its ortholog p73. Here we describe a study showing that this coactivator also
regulates the transcriptional function of p63. p300 bound to the N-terminal domain of p63γ,
and p63γ bound to the N terminus of p300 in vitro and in cells. p300, but not its acetylase-
defective mutant AT2, stimulated p63γ-dependent transcription and induction of p21 in cells,
consequently leading to G 1 arrest. Inversely, the ΔN-p63γ isoform as well as p300AT2 …