UNC3474, a small molecule ligand, selectively interacts with the aromatic methyl-lysine binding cage of the tumor protein 53BP1 Tudor domain (TT), exhibiting a dissociation constant (Kd) of 1.0±0.3 μM. It impedes 53BP1's recruitment to DNA double-strand breaks (DSBs), maintaining the protein's autoinhibited state within cells [1].