CBP and p300 are large nuclear proteins that bind to many sequence-specific factors involved in cell growth and/or differentiation, including c-jun and the adenoviral oncoprotein E1A. PCAF exerts histone acetyltransferase activity in association with core histones (H3 and H4) and with nucleosome core particles, and functions to promote transcriptional activation. It has histone acetyl transferase activity with core histones and nucleosome core particles, indicating that this protein plays a direct role in transcriptional regulation.
