New publication in "ACS Chemical Biology"
SUV39H1 was the first human protein lysine methyltransferase that has been discovered in 2000. It is known to introduce methylation of histone 3 at lysine 9, but so far no additional substrates have been described. H3K9me3. To identify novel SUV39H1 substrates, we determined its specificity profile showing that several residues on both sides of the methylation target K9 are important for peptide interaction. The specificity profile of SUV39H1 is distinct from its paralog SUV39H2 suggesting that they have non-redundant functions. Based on the specificity profile we describe several novel SUV39H1 substrates and confirmed cellular methylation of RAG2, SET8 and DOT1L. We investigated the biological role of the methylation of these proteins and show that methylation of RAG2 alters its sub-nuclear localization and methylation of SET8 increases its activity. We conclude that SUV39 is part of a network of proteins interacting with chromatin and it has a broader role in the regulation of processes on chromatin beyond generating H3K9 trimethylation.