RBL2 (also known as p130) or Retinoblastoma-like protein 2 is a key regulator of entry into cell division. It is directly involved in heterochromatin formation by maintaining overall chromatin structure and (in particular) that of constitutive heterochromatin by stabilizing histone methylation. RBL2 recruits and targets histone methyltransferases KMT5B and KMT5C leading to epigenetic transcriptional repression. It controls histone H4 'Lys20' trimethylation. It probably also acts as a transcription repressor by recruiting chromatin-modifying enzymes to promoters. RBL2 serves as a potent inhibitor of E2F-mediated trans-activation and associates preferentially with E2F5.