Anti-phospho-4E BP1 (Ser83) Antibody, clone CM14D3

Eukaryotic translation initiation factor 4E-binding protein 1 (UniProt: Q13541; also known as 4E-BP1, eIF4E-binding protein 1, Phosphorylated heat- and acid-stable protein regulated by insulin 1, PHAS-I) is encoded by the EIF4EBP1 gene (Gene ID: 1978) in human. 4E-BP1 is a member of a family of translation repressor proteins, and a well-known substrate of mTOR signaling pathway. In response to upstream stimuli, such as insulin, EGF, and PDGF, mTORC1 is shown to phosphorylate S6 kinase 1 (S6K1) and 4E-BP1 that stimulates protein synthesis. About 30% of the 4E-BP1 expressed in cells is localized in the nucleus, where it regulates the availability of eIF4E for the cytoplasmic translational machinery, by retaining eIF4E in the nucleus. 4E-BP1 can undergo phosphorylation at multiple sites (Thr 37, 46, 70 and Ser 65, 83, 101, and 112) and the first five sites are phylogenetically conserved among all species. The phosphorylated form is also considered as a marker of activated mTOR signaling. Phosphorylations at Thr37 and Thr46 serve as a priming event, which is followed by phosphorylation at Thr70 and then at Ser 65. The hyperphosphorylated form is regulated by mTORC1 and abolishes binding to elF4E. Several other kinases have also been shown to phosphorylate 4E-BP1 dependent or independent of mTOR. Phosphorylation of 4E-BP1 at Thr37 and Thr46 by GSK3 reduces its association with elF4E and its release from eIF4E allows cap-dependent translation to proceed. High level of phosphorylated 4E-BP1 is reported in several human cancers and is associated with an unfavorable outcome in several malignancies. Overexpression of cytosolic 4E-BP1 is reported to orchestrate a hypoxia-activated switch from cap-dependent to cap-independent mRNA translation that promotes increased tumor angiogenesis and growth at the level of selective mRNA translation. (Ref.: Qin, X., et al. (2016). Cell Cycle. 15(6); 781-786).

Clone CM14D3 is a rat monoclonal antibody that detects Eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylated on serine 83.

KLH-conjugated linear peptide corresponding to 13 amino acids from surrounding phosphoserine 83 from the C-terminal half of human Eukaryotic translation 4E-BP1.

Quality Control Testing

Evaluated by Western Blotting in lysate from A431 cells treated with PMA.

Western Blotting Analysis (WB): A 1:500 dilution of this antibody detected 4E-BP1 in lysate from A431 cells treated with PMA (200 nM, 20 min. at 37C), but not in untreated cells.

Anti-phospho-4E BP1 (Ser83), clone CM14D3, Cat. No. MABS2243, is a rat monoclonal antibody that detects Eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylated on serine 83 and is tested for use in Western Blotting.

Purified rat monoclonal antibody IgG2a in buffer containing 0.1 M Tris-Glycine (pH 7.4), 150 mM NaCl with 0.05% sodium azide.

Recommend storage at +2°C to +8°C. For long term storage antibodies can be kept at -20°C. Avoid repeated freeze-thaws.

Concentration: Please refer to the Certificate of Analysis for the lot-specific concentration.

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