GCN5: The members of Gcn5-related N-acetyltransferase (GNAT) family structurally resemble the archetypal HAT Gcn5 and have been relatively well studied. They share the highly conserved catalytic HAT domain with characteristic sequence motifs, of which motif A notably binds acetyl-coA. Some members additionally have an N-terminal PCAF homology domain for substrate selectivity and a C-terminal bromodomain for binding acetylated lysine residues. As is the case with most HATs, GCN5 functions as the catalytic component in multi-subunit complexes SAGA, ADA and SLIK, playing important roles in transcriptional activation and various chromatin activities (1)

Reference
1. Jeon J. H., Lee Y. H.Histone acetylation in fungal pathogens of plants. Plant Pathol.J.2014;30(1):1-9. PMID: 25288980.

    HAT1: The best-understood set of acetyltransferases is the GNAT (Gcn5-related N-acetyltransferase) superfamily, which have been grouped together on the basis of their similarity in several homology regions and acetylation-related motifs. This group includes the HAT Gcn5, its close relatives, and at least three more distantly related HATs, Hat1, Elp3, and Hpa2. (1)

    Hat1 is the sole known example of a type B histone acetyltransferase. While it has long been presumed that type B histone acetyltransferases participate in the acetylation of newly synthesized histones during the process of chromatin assembly.

Reference
1. Sterner, D.E. & Berger, S.L.Acetylation of histones and transcription-related factors. Microbiol. Mol. Biol. Rev.2000;64(2):435-459. PMID: 10839822.

    MYST: The MYST family, which was named after the initials of the founding members: MOZ, Ybf2/Sas3, Sas2, and Tip60, is the largest family of acetyltransferases with diverse biological functions. In the budding yeast, Esa1 of the NuA4 complex is known to be an essential HAT required for DNA repair and cell cycle progression. In animal systems, the role of MYST family HATs in stem cells, development and cancer have been thoroughly documented. It is of note that MYST family HAT complexes are known to have the broadest range of substrates including non-histone targets. The regulatory role and the ubiquity of protein acetylation had long been suspected to be comparable that of phosphorylation. (1)

Reference
1. Jeon J. H., Lee Y. H.Histone acetylation in fungal pathogens of plants. Plant Pathol.J.2014;30(1):1-9. PMID: 25288980.