Anti-Phospho-Rb (Ser807) mAb

WB - 1-2 ug/mL IP - 2-4 ug/sample ELISA - 5-10ug/mL

The retinoblastoma protein (Rb) is a nuclear phosphoprotein that regulates growth in the G1 phase of the cell cycle. Rb exerts its growth-inhibitory effects in part by binding to and inhibiting critical regulatory proteins, including members of the E2F family of transcription factors; E2F activation is necessary for the G1-S transition. E2F selectively associates with hypophosphorylated Rb, and phosphorylation of Rb appears to release E2F from an inhibitory complex, enabling it to promote the transcription necessary for progression into late G1 and S. Rb is phosphorylated on a still imprecisely defined number of threonine and serine residues during G1 (1, 2). Both Ser608) and Ser780 have been identified as among the sites that are initially phosphorylated. These phosphorylations have distinct effects on the ability of Rb to interact with its various partner proteins. Thus, Rb phosphorylated on Ser780 appears to lose its ability to bind to E2F. Phosphorylation of Ser807 and/or Ser811 is required to abolish Rb binding to c-Abl, while modification of Thr821) and/or Thr826 is required to abolish Rb binding to LXCXE-containing proteins such as simian virus 40 large T antigen. However, these four sites do not appear to be involved in regulating Rb binding to the E2F transcription factors. Phosphorylation of Rb also has effects on cell physiology, ostensibly by changing its association with these and other interacting partner proteins. For example, phosphorylation of Ser795 is required to inactivate Rb-imposed growth suppression in a microinjection assay. However, the relationship between growth inhibition and E2F binding is complex: phosphorylation of Rb in vitro by cyclin D-, cyclin E-, or cyclin A-associated kinase has been reported to release E2F, yet only action by cyclin D1?cyclin-dependent kinase 4 (cdk4) complexes, but not by cyclin E-cdk2 complexes, abrogates the growth-inhibitory property of Rb when microinjected into SaOS-2 cells.

1.0 mg/mL

Supplied in 20mM phosphatase buffer (pH 7.5), 300mM NaCl, 50% glycerol.

Human: 5925 Mouse: 19645

Near the Ser807 phosphorylated peptide synthesis of human Rb (binding KLH)

The Phospho-Rb Ser612 Antibody detects endogenous Rb protein only when phosphorylated at Ser807. Recognizes human phospho-Ser807 Rb protein (~115 kDa); not tested in other species.

1 year

Monoclonal antibody is produced by immunizing mice with a synthetic phosphopeptide (KLH coupled) corresponding to residues surrounding Ser807 of human Rb. The IgG fraction was purified by protein A-Sepharose chromatography.

pRB