Competitive Inhibition of Lysine Acetyltransferase 2B by a Small Motif of the Adenoviral Oncoprotein E1A

Shasha Shi,Ke Liu,Yanheng Chen,Shijun Zhang,Juanyu Lin,Chenfang Gong,Quanwen Jin,Xiang-Jiao Yang,Ruichuan Chen,Zhiliang Ji,Aidong Han

doi:10.1074/jbc.m115.697300

Shasha Shi, Ke Liu + Show 9 more

Open Access

https://doi.org/10.1074/jbc.m115.697300

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Abstract

The adenovirus early region 1A (E1A) oncoprotein hijacks host cells via direct interactions with many key cellular proteins, such as KAT2B, also known as PCAF (p300/CBP associated factor). E1A binds the histone acetyltransferase (HAT) domain of KAT2B to repress its transcriptional activation. However, the molecular mechanism by which E1A inhibits the HAT activity is not known. Here we demonstrate that a short and relatively conserved N-terminal motif (cNM) in the intrinsically disordered E1A protein is crucial for KAT2B interaction, and inhibits its HAT activity through a direct competition with acetyl-CoA, but not its substrate histone H3. Molecular modeling together with a series of mutagenesis experiments suggests that the major helix of E1A cNM binds to a surface of the acetyl-CoA pocket of the KAT2B HAT domain. Moreover, transient expression of the cNM peptide is sufficient to inhibit KAT2B-specific H3 acetylation H3K14ac in vivo Together, our data define an essential motif cNM in N-terminal E1A as an acetyl-CoA entry blocker that directly associates with the entrance of acetyl-CoA binding pocket to block the HAT domain access to its cofactor.

Highlights

Adenoviruses, small DNA viruses with genomes of ϳ35 kb have evolved to infect a broad range of animal species and human beings [1, 2]
A series of peptides of E1A2 (E1A from serotype 2 adenovirus) were chemically synthesized, some of which were labeled with the fluorescent probe FITC (Table 1)
We examined the interactions of these peptides with 6ϫ His-tagged KAT2B histone acetyltransferase (HAT) domain (493– 658 aa) using NTA affinity pulldown assay (NTA pulldown) (Fig. 1A)

Summary

Introduction

Adenoviruses, small DNA viruses with genomes of ϳ35 kb have evolved to infect a broad range of animal species and human beings [1, 2]. We demonstrate that a short and relatively conserved N-terminal motif (cNM) in the intrinsically disordered E1A protein is crucial for KAT2B interaction, and inhibits its HAT activity through a direct competition with acetyl-CoA, but not its substrate histone H3. Molecular modeling together with a series of mutagenesis experiments suggests that the major helix of E1A cNM binds to a surface of the acetyl-CoA pocket of the KAT2B HAT domain.

Results

Conclusion