Cell Signaling Technology

Product Pathways - NF-kappaB Signaling

Phospho-IκBε (Ser18/22) Antibody #4924

Applications Reactivity Sensitivity MW (kDa) Source
W H M R (B) (Dg) Endogenous 45 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat  B=Bovine  Dg=Dog
Species cross-reactivity is determined by Western blot.

Protocols

Specificity / Sensitivity

Phospho-IκBε (Ser18/22) Antibody detects endogenous levels of IκBε only when phosphorylated at serines 18 and 22. No cross-reactivity was detected with other family members at physiological conditions.

Source / Purification

Polyclonal antibodies are prepared by immunizing rabbits with a synthetic phospho-peptide (KLH-coupled) corresponding to residues surrounding serine 18/22 of human IκBε. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from 293 cells treated with TNF-α (20 ng/ml) for the indicated times, using Phospho-IκBε (Ser18/22) Antibody.

Background

The NF-κB/Rel transcription factors are present in the cytosol in an inactive state complexed with the inhibitory IκB proteins (1-3). Activation occurs via phosphorylation of IκBα at Ser32 and Ser36 followed by proteasome-mediated degradation that results in the release and nuclear translocation of active NF-κB (3-7). IκBα phosphorylation and resulting Rel-dependent transcription are activated by a highly diverse group of extracellular signals including inflammatory cytokines, growth factors and chemokines. Kinases that phosphorylate IκB at these activating sites have been identified (8).

The regulation of IκBβ and IκBε is similar to that of IκBα. However, the phosphorylation and ubiquitin-mediated degradation of these proteins occurs with much slower kinetics (9). IKK phosphorylation of IκBβ occurs at Ser19 and Ser23, while IκBε can be phosphorylated at Ser18 and Ser22 (10).

  1. Baeuerle, P.A. and Baltimore, D. (1988) Science 242, 540-6.
  2. Beg, A.A. and Baldwin, A.S. (1993) Genes Dev 7, 2064-70.
  3. Finco, T.S. et al. (1994) Proc Natl Acad Sci USA 91, 11884-8.
  4. Brown, K. et al. (1995) Science 267, 1485-8.
  5. Brockman, J.A. et al. (1995) Mol Cell Biol 15, 2809-18.
  6. Traenckner, E.B. et al. (1995) EMBO J 14, 2876-83.
  7. Chen, Z.J. et al. (1996) Cell 84, 853-62.
  8. Karin, M. and Ben-Neriah, Y. (2000) Annu Rev Immunol 18, 621-63.
  9. Hoffmann, A. et al. (2002) Science 298, 1241-1245.
  10. Shirane, M. et al. (1999) J. Biol. Chem. 274, 28169-28174.

Application References

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Companion Products

This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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