Structural Basis of H2B Ubiquitination-Dependent H3K4 Methylation by COMPASS (Molecular Cell)

The cryo-EM structures of the yeast COMPASS methyltransferase bound to H2Bub and unmodified nucleosomes reveal an arginine-rich motif in the catalytic subunit, whose autoinhibitory effect on the enzymatic complex is overridden by H2B-conjugated ubiquitin. The study sheds light on the mechanism of an evolutionarily conserved crosstalk between two histone modifications.