PCAF also known as P300/CBP-associated factor, P/CAF, KAT2B is a histone acetyltransferase (HAT) that plays a pivotal role in regulating gene expression by acetylating lysine residues on histone proteins, leading to chromatin remodeling and transcriptional activation. This modification relaxes the chromatin structure, allowing transcription factors easier access to DNA and thereby influencing crucial cellular processes such as cell cycle progression, differentiation, and response to external signals. PCAF also acetylates non-histone proteins, affecting their function and stability, which underscores its importance in various cellular pathways.