anti-pRb, mAb (Retinoblastoma Protein) (32C8)

The Rb protein (pRb, 110kDa) is a tumor suppressor, which plays a pivotal role in the negative control of the cell cycle and in tumor progression. pRb is responsible for a major G1 checkpoint, blocking S-phase entry and cell growth. pRb prevents the cell from replicating damaged DNA by preventing its progression through the cell cycle into its S phase or progressing through G1 phase. pRb can actively inhibit cell cycle progression when it is dephosphorylated while this function is inactivated when pRb is phosphorylated. pRb is activated near the end of mitosis (M phase) when a phosphatase dephosphorylates it, allowing it to bind E2F. The pRb protein represses gene transcription, required for transition from G1 to S phase, by directly binding to the transactivation domain of E2F and by binding to the promoter of these genes as a complex with E2F. Key regulator of entry into cell division that acts as a tumor suppressor. Acts as a transcription repressor of E2F1 target genes. The underphosphorylated, active form of RB1 interacts with E2F1 and represses its transcription activity, leading to cell cycle arrest. Directly involved in heterochromatin formation by maintaining overall chromatin structure and, in particular, that of constitutive heterochromatin by stabilizing histone methylation. Recruits and targets histone methyltransferases SUV39H1, SUV420H1 and SUV420H2, leading to epigenetic transcriptional repression. Controls histone H4 'Lys-20' trimethylation. Inhibits the intrinsic kinase activity of TAF1. In case of viral infections, interactions with SV40 large T antigen, HPV E7 protein or adenovirus E1A protein induce the disassembly of RB1-E2F1 complex thereby disrupting RB1's activity.