Functional Investigations of p53 Acetylation Enabled by Heterobifunctional Molecules

Post-translational
modifications (PTMs) dynamically regulate the
critical stress response and tumor suppressive functions of p53. Among
these, acetylation events mediated by multiple acetyltransferases
lead to differential target gene activation and subsequent cell fate.
However, our understanding of these events is incomplete due to, in
part, the inability to selectively and dynamically control p53 acetylation.
We recently developed a heterobifunctional small molecule system,
AceTAG, to direct the acetyltransferase p300/CBP for targeted protein
acetylation in cells. Here, we expand AceTAG to leverage the acetyltransferase
PCAF/GCN5 and apply these tools to investigate the functional consequences
of targeted p53 acetylation in human cancer cells. We demonstrate
that the recruitment of p300/CBP or PCAF/GCN5 to p53 results in distinct
acetylation events and differentiated transcriptional activities.
Further, we show that chemically induced acetylation of multiple hotspot
p53 mutants results in increased stabilization and enhancement of
transcriptional activity. Collectively, these studies demonstrate
the utility of AceTAG for functional investigations of protein acetylation.