Polycomb group (PcG) protein that specifically recognizes and binds mono- and dimethyllysine residues on target proteins, therey acting as a 'reader' of a network of post-translational modifications. PcG proteins maintain the transcriptionally repressive state of genes
In response to DNA damage, VCP/p97, an ATPase which unfolds proteins, removes L3MBTL1 from H4K20me2, creating free H4K20me2 for 53BP1 to bind to (Fig. 3b).