Jumonji AT-rich interactive domain 1 (JARID1) demethylases mediate the removal of methyl groups from trimethylated lysine 4 on histone 3 (H3K4me3). PBIT is a reversible, cell-permeable inhibitor of JARID1 family demethylases (IC50s = 6, 3, 4.9, and 28 μM for JARID1A, JARID1B, JARID1C, and JARID1D, respectively). It does not significantly affect the activity of UTX and JMJD3 demethylases. It increases trimethylation of H3K4 in HeLa cells and blocks the proliferation of tumor cells expressing high levels of JARID1B.
