retinoblastoma-associated protein-like p107 homolog; retinoblastoma-like protein 1; PRB1; 107 kD retinoblastoma-associated protein; p107 (RBL1)

^[1]^[2]

Function

key regulator of entry into cell division
directly involved in heterochromatin formation by maintaining overall chromatin structure &, in particular, that of constitutive heterochromatin by stabilizing histone methylation
recruits & targets histone methyltransferases SUV420H1 & SUV420H2, leading to epigenetic transcriptional repression
controls histone H4 Lys-20 trimethylation
probably acts as a transcription repressor by recruiting chromatin-modifying enzymes to promoters
potent inhibitor of E2F-mediated trans-activation
forms a complex with adenovirus E1A & with SV40 large T antigen
may bind & modulate functionally certain cellular proteins with which T & E1A compete for pocket binding
may act as a tumor suppressor
interacts with SUV420H1 & SUV420H2 (putative)
component of the DREAM complex (also named LINC complex) at least composed of E2F4, E2F5, LIN9, LIN37, LIN52, LIN54, MYBL1, MYBL2, RBL1, RBL2, RBBP4, TFDP1 & TFDP2
the complex exists in quiescent cells where it represses cell cycle-dependent genes
dissociates in S phase when LIN9, LIN37, LIN52 & LIN54 form a subcomplex that binds to MYBL2
interacts with AATF
interacts with JARID1A
exists in both phosphorylated & unphosphorylated forms
SV40 large T antigen, but not E1A, binds only to the unphosphorylated form
cell-cycle arrest properties are inactivated by phosphorylation on Thr-332, Ser-640, Ser-964 & Ser-975 by CDK4

belongs to the retinoblastoma protein (RB) family