The retinoblastoma protein (protein name abbreviated pRb; gene name abbreviated RB or RB1) is a tumor suppressor protein that is dysfunctional in several major cancers. One function of pRb is to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide. When the cell is ready to divide, pRb is phosphorylated, becomes inactive and allows cell cycle progression. It is also a recruiter of several chromatin remodeling enzymes such as methylases and acetylases.

Rb restricts the cell"s ability to replicate DNA by preventing its progression from the G1 (first gap phase) to S (synthesis phase) phase of the cell division cycle. Rb binds and inhibits transcription factors of the E2F family, which are composed of dimers of an E2F protein and a dimerization partner (DP) protein. The transcription activating complexes of E2 promoter-binding–protein-dimerization partners (E2F-DP) can push a cell into S phase. As long as E2F-DP is inactivated, the cell remains stalled in the G1 phase. When Rb is bound to E2F, the complex acts as a growth suppressor and prevents progression through the cell cycle. The Rb-E2F/DP complex also attracts a histone deacetylase (HDAC) protein to the chromatin, reducing transcription of S phase promoting factors, further suppressing DNA synthesis.[Wiki]

mAb 1F8 ecognizes a 105kDa phosphoprotein, identified as retinoblastoma (Rb) gene product. It shows no cross reaction with p107 or p130. It specifically stains the nuclei of BT-20 cells and primary human foreskin fibroblast (HFF) cells. It does not stain the Rb-negative BT549 cells. It reacts with the hyperphosphorylated as well as the un (under) phosphorylated form of the Rb protein.

Titering of the Rb antibody may be required for optimal performance.

A human recombinant partial protein was used as the immunogen for this Rb antibody. The epitope is localized within amino acids 703-772.

The Rb antibody (with azide) can be stored at 2-8oC. The azide-free format should be aliquoted and stored at -20oC or colder.