The function of EPC1 (enhancer of polycomb 1, ENSG00000120616) is as follows. Component of the NuA4 histone acetyltransferase (HAT) complex, a multiprotein complex involved in transcriptional activation of select genes principally by acetylation of nucleosomal histones H4 and H2A (PubMed:14966270). The NuA4 complex plays a direct role in repair of DNA double-strand breaks (DSBs) by promoting homologous recombination (HR) (PubMed:27153538). The NuA4 complex is also required for spermatid development by promoting acetylation of histones: histone acetylation is required for histone replacement during the transition from round to elongating spermatids (By similarity). In the NuA4 complex, EPC1 is required to recruit MBTD1 into the complex (PubMed:32209463). {ECO:0000250|UniProtKB:Q8C9X6, ECO:0000269|PubMed:14966270, ECO:0000269|PubMed:27153538, ECO:0000269|PubMed:32209463}.