Effects of Oncohistone Mutations and PTM Crosstalk on the N-terminal Acetylation Activities of NatD

Acetylation at the α-N-terminus (Nα) is one of the most abundant modifications detected on histone H4 and H2A, which is catalyzed by N-terminal acetyltransferase D (NatD). NatD substrate recognition motif, N-terminal SGRGK, is enriched with frequent oncohistone mutations and post-translational modifications (PTMs). However, there is no information on how oncohistone mutations and other PTMs affect NatD-catalyzed acetylation. Herein, we determined how changes of local chemical environment on the N-terminal SGRGK sequence regulate NatD-catalyzed Nα acetylation on histone H4/H2A. Our studies indicate that all oncohistone mutations at SGRG suppressed the catalytic efficiency of NatD. Meanwhile, H4 serine 1 phosphorylation and arginine 3 methylation also negatively affect the NatD activity, but the lysine 5 acetylation has a marginal effect on NatD. This work reveals the impacts of oncohistone mutations on NatD activity and unravels the crosstalk between NatD and PTMs. To our knowledge, this is the first report on the potential regulatory mechanism of NatD, highlighting different revenues to interrogate the NatD-mediated pathway in the future.