HPL-1 physical interacts with HIS-24 when monomethylated at lysine 14. HPL-1 physical interacts with HIS-24 when monomethylated at lysine 14. (A and B) HPL-1 and HPL-2 coprecipitate HIS-24K14me1. An enrichment relative to input of methylated HIS-24 compared to total HIS-24 is observed for HPL-1 but not HPL-2 (no enrichment). (C and D) HPL-1 coprecipitates HPL-2, but HPL-2 does not pull down HIS-24 in an hpl-1(tm1624) mutant background. (E and F) Recombinant HPL-1 protein specifically recognizes the HIS-24K14me1 region but neither H3K9me2 nor H3K9me3 in peptide pulldown assays. Recombinant HPL-2 does not interact with the HIS-24K14me1 peptide. α, anti; IP, immunoprecipitation. Studencka M et al. Mol. Cell. Biol. 2012;32:251-265