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Tematically revealed that PHF8 is a pro-inflammatory chromatin regulator of a Tematically revealed that PHF8 is a pro-inflammatory chromatin regulator of a broad range of the genes and associated biological processes/pathways. This dataset of the LPS-inducible, PHF8-dependent, T-class secretome not only identifies a large number of PHF8-regulated pro-inflammatory cytokines, but also extends our knowledge of novel PHF8 functions that regulate acute inflammation and overall immunity, including the activation of adaptive immunity. For the first time, we identified the epigenetic regulatory link between the innate immune response and the activation of adaptive immunity where the LPS-induced secretion of specific proteins involved in the associated T-cell activation/proliferation is PHF8-dependent. Our data also showed that, under an acute inflammatory condition, the gene-specific-repressive function of the Kme writer G9a is antagonized by the Kme eraser PHF8, elucidating the mechanism underlying the gene-specific chromatin plasticity that corresponds to changes in cellular immune responses to LPS stimulation(s). Our quantitative proteomic strategy to dissect LPS-inducible, inflammatory-phenotypic secretome has led us to discover novel PHF8 functions that control inflammation and overall immunity at the post-translational level. These findings are highly physiological-relevant and are not accessible by conventional transcriptome approaches. Thus, this secretome screening method generates the simultaneous multi-target quantitative datasets without the need of antibodies on mass spectrometry, which is otherwise equivalent to that of hundreds or thousands of `western blots' or ELISA.Resultsare targeted/modulated by PP2Ac, we used an amino-acid-coded mass tagging (AACT)-based quantitative phosphoproteomic approach16 to comparatively analyze changes in site-specific phosphorylation levels in WT versus PP2Ac-KD RAW 264.7 cells, which led to identifications of the protein substrates directly or indirectly targeted by chronically activated PP2Ac (Supplementary Fig. 1a). Multiple protein components involved in multiple chromatin-associated BPs showed significantly enhanced phosphorylation in PP2AcKD-TL compared to WT-TL, indicating that each of these proteins contains phosphorylation site(s) that could be dephosphorylated by chronically active PP2Ac in ET macrophages (Fig. 1a and Supplementary Fig. 1b). Some of these proteins, including Histone deacetylases 1/2 (HDAC1/2), DNA methyltransferase 1 (DNMT1), and methyl-CpG binding protein 2 (MeCP2), were previously characterized as the major components of co-repressor complexes. Our quantitative phosphoproteomic data showed that PP2Ac dephosphorylates the transcription-regulating S421/423 pair of HDAC117 to inhibit dimerization with HDAC2 in the transcriptionally repressive chromatin state (Supplementary Fig. 1c, top). Also, we found that the epigenetic regulator MeCP2 was dephosphorylated by PP2Ac at phosphoS80 that is associated with induction of apoptotic genes18 (Supplementary Fig. 1c, bottom). Strikingly, associating with these PP2Ac-mediated chromatin reprogramming, we identified three serine residues (S768, S820, and S843) within or near the serine-rich region of the PHF8 (Supplementary Fig. 1d) that showed increased phosphorylation in PP2AcKD-TL compared with phosphorylation in WT-TL (Supplementary Fig. 1e,f ), indicating that chronically activated PP2Ac may dephosphorylate PHF8 in ET. To determine if the KDM activity of PHF8 could be affected in ET macrophages by chronic-.