Cell Signaling Technology

Product Pathways - Translational Control

Phospho-eIF4B (Ser406) Antibody #5399

Applications Reactivity Sensitivity MW (kDa) Source
W IP IF-IC H M (R) Endogenous 80 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  IF-IC=Immunofluorescence (Immunocytochemistry)
Reactivity Key:  H=Human  M=Mouse  R=Rat
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-eIF4B (Ser406) Antibody detects endogenous levels of eIF4B protein only when phosphorylated at Ser406.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Ser406 of human eIF4B protein. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from NIH/3T3 cells, untreated or λ phosphatase treated, using Phospho-eIF4B (Ser406) Antibody (upper) or eIF4B Antibody #3592 (lower).

IF-IC

IF-IC

Confocal immunofluorescent analysis of HeLa cells, untreated (upper) or λ phosphatase treated (lower), using Phospho-eIF4B (Ser406) Antibody (green). Actin filaments were labeled with DY-554 phalloidin (red). Blue pseudocolor= DRAQ5® #4084 (fluorescent DNA dye).

Background

Eukaryotic initiation factor 4B (eIF4B) is thought to assist the eIF4F complex in translation initiation. In plants, eIF4B is known to interact with the poly-(A) binding protein, increasing its poly-(A) binding activity (1). Heat shock and serum starvation cause dephosphorylation of eIF4B at multiple sites with kinetics similar to those of the corresponding inhibition of translation, while phosphorylation of eIF4B following insulin treatment correlates well with an observed increase in translation (2-5). Multiple kinases, including p70 S6 kinase, can phosphorylate eIF4B in vitro, and at least one serum-inducible eIF4B phosphorylation site is sensitive to rapamycin and LY294002 (6). Recently, Ser406 was identified as a novel phosphorylation site regulated by mitogens (7), and the phosphorylation of this site is dependent on MEK and mTOR activity (7). This phosphorylation is shown to be essential for the translational activity of eIF4B (7).

  1. Le, H. et al. (1997) J. Biol. Chem. 272, 16247-16255.
  2. Duncan, R.F. and Hershey, J.W. (1989) J. Cell Biol. 109, 1467-1481.
  3. Duncan, R.F. and Hershey, J.W. (1984) J. Biol. Chem. 259, 11882-11889.
  4. Duncan, R. and Hershey, J.W. (1985) J. Biol. Chem. 260, 5493-5497.
  5. Manzella, J.M. et al. (1991) J. Biol. Chem. 266, 2383-2389.
  6. Gingras, A.C. et al. (2001) Genes Dev. 15, 807-826.
  7. van Gorp, A.G. et al. (2009) Oncogene 28, 95-106.

Application References

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