Identification of PWWP2A interactors using label-free quantitative affinity enrichment mass spectrometry

Chromatin structure and function is regulated by reader proteins recognizing histone modifications and/or histone variants. We recently identified PWWP2A, which tightly binds to H2A.Z-containing nucleosomes and is involved in mitotic progression and cranial-facial development. Here, using in vitro assays we show that distinct domains of PWWP2A moreover mediate binding to free linker DNA as well as H3K36me3 nucleosomes. In vivo, PWWP2A strongly recognizes H2A.Z-containing regulatory regions and weakly H3K36me3-containing gene bodies. Additionally, PWWP2A bind to an MTA1-specific core NuRD (M1HR) complex solely consisting of MTA1, HDAC1 and RBBP4/7, excluding CHD and MBD proteins. Depletion of PWWP2A leads to an increase of acetylation levels on H3K27 as well as H2A.Z, presumably by impaired chromatin recruitment of M1HR. Thus, this study identifies PWWP2A as an ever more complex chromatin binding protein serving as adapter for M1HR to H2A.Z-containing chromatin, thereby promoting changes in histone acetylation levels and likely fine-tuning the transcriptional balance.