The interaction between STATs and coactivators occurs through the transactivation domains (TADs) of STATs.[2] The TADs on STATs can also interact with histone acetyltransferases (HATs);[14] these HATs add acetyl groups to lysine residues on proteins associated with DNA called histones. Adding acetyl groups removes the positive charge on lysine residues, and as a result there are weaker interactions between histones and DNA, making DNA more accessible to STATs and enabling an increase in the transcription of target genes.