KAT2B, also known as PCAF (p300/CBP-associated factor), is a crucial transcriptional coactivator that possesses intrinsic histone acetyltransferase (HAT) activity. It primarily acetylates histone H3 at lysine 9 (H3K9ac) and lysine 14 (H3K14ac), a modification associated with open chromatin and active gene transcription. Functionally, PCAF is recruited to promoters by interacting with various transcription factors (such as p53, NF-κB, and nuclear receptors) and larger complexes like the p300/CBP cointegrator complex. It plays pivotal roles in diverse cellular processes, including cell cycle progression, differentiation, metabolism, DNA damage response, and tumor suppression or promotion in a context-dependent manner. Due to its involvement in critical pathways, PCAF is a significant protein of interest in epigenetics, cancer biology, and neurodevelopmental research.