EP300 is a histone acetyltransferase that regulates transcription via chromatin remodeling. It acetylates all four core histones in nucleosomes. EP300 mediates cAMP-gene regulation by binding specifically to phosphorylated CREB protein. It also plays a role as a coactivator of NEUROD1-dependent transcription of the secretin and p21 genes and controls terminal differentiation of cells in the intestinal epithelium. EP300 can also promote cardiac myocyte enlargement. In infectious disease, it binds to and may be involved in the transforming capacity of the adenovirus E1A protein, and in case of HIV-1 infection, it is recruited by the viral protein Tat. It regulates Tat's transactivating activity and may help inducing chromatin remodeling of proviral genes. In immunohistochemistry, EP300 has nuclear and cytoplasmic positivity in a majority of tissues throughout the body. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804;