The key roles of the lysine acetyltransferases KAT6A and KAT6B in physiology and pathology.

Histone modifications and more specifically ε-lysine acylations are key epigenetic regulators that control chromatin structure and gene transcription, thereby impacting on various important cellular processes and phenotypes. Furthermore, lysine acetylation of many non-histone proteins is involved in key cellular processes including transcription, DNA damage repair, metabolism, cellular proliferation, mitosis, signal transduction, protein folding, and autophagy. Acetylation affects protein functions through multiple mechanisms including regulation of protein stability, enzymatic activity, subcellular localization, crosstalk with other post-translational modifications as well as regulation of protein-protein and protein-DNA interactions. The paralogous lysine acetyltransferases KAT6A and KAT6B which belong to the MYST family of acetyltransferases, were first discovered approximately 25 years ago. KAT6 acetyltransferases acylate both histone H3 and non-histone proteins. In this respect, KAT6 acetyltransferases play key roles in regulation of transcription, various developmental processes, maintenance of hematopoietic and neural stem cells, regulation of hematopoietic cell differentiation, cell cycle progression as well as mitosis. In the current review, we discuss the physiological functions of the acetyltransferases KAT6A and KAT6B as well as their functions under pathological conditions of aberrant expression, leading to several developmental syndromes and cancer. Importantly, both upregulation and downregulation of KAT6 proteins was shown to play a role in cancer formation, progression, and therapy resistance, suggesting that they can act as oncogenes or tumor suppressors. We also describe reciprocal regulation of expression between KAT6 proteins and several microRNAs as well as their involvement in cancer formation, progression and resistance to therapy.