MRG-binding protein, also known as MRGBP, is a 204 amino acid protein which is a part of the NuA4 histone acetyltransferase (HAT) complex that acts to acetylate histone H2A and H4. This complex may be required for the activation of transcriptional programs associated with oncogene and proto-oncogene mediated growth induction, tumor suppressor mediated growth arrest and replicative senescence, apoptosis, and DNA repair.