Catalytic component of the NuA4 histone acetyltransferase (HAT) complex which is involved in epigenetic transcriptional activation of selected genes principally by acetylation of nucleosomal histones H4; H3; H2B; H2A and H2A variant H2A.Z. Acetylates histone H4 to form H4K5ac; H4K8ac; H4K12ac and H4K16ac; histone H3 to form H3K14ac; histone H2B to form H2BK16ac; and histone H2A to form H2AK4ac and H2AK7ac. Acetylation of histone H4 is essential for DNA double-strand break repair through homologous recombination. Involved in cell cycle progression. Recruitment to promoters depends on H3K4me. {ECO:0000250|UniProtKB:Q08649}.