Domain architecture of the BET family proteins used in this study and H2A.Z acetylation marks. (a) Domain topologies of the ubiquitously expressed human BET proteins BRD2, BRD3, and BRD4. The bromodomains (BDs), extra terminal domain (ET), and the C‐terminal domain of each protein are indicated. (b) Sequence comparison of the N‐terminal residues of human H2A.Z, H2A, and H4. The acetylation sites investigated in this study are boxed in gray. The AcK residues of the H4 diacetylation motif that is known to mediate an interaction with the BET BDs is also shown