Cell Signaling Technology

Product Pathways - NF-kappaB Signaling

Phospho-IκB-β (Ser19/23) Antibody (Mouse/Rat Specific) #9245

Applications Reactivity Sensitivity MW (kDa) Source
W M R Endogenous 50 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  M=Mouse  R=Rat
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-IκB-β (Ser19/23) Antibody detects endogenous levels of IκB-β only when phosphorylated at Ser19/23.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic phospho-peptide (KLH-coupled) corresponding to residues surrounding Ser19/23 of murine IκB-β. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from NIH-3T3 cells treated for 5 minutes with TNF-α #2169 (20 ng/ml), calyculin A #9902 (50 nM), or both compounds, using Phospho-IκB-β (Ser19/23) Antibody (top), or IkappaB-beta Antibody #9248 (bottom).

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 IκB-α at Ser32 and Ser36 followed by proteasome-mediated degradation that results in the release and nuclear translocation of active NF-κB (3-7). IκB-α 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). Because phosphorylation of IκB-α at Ser32/36 is essential for release of active NF-κB, phosphorylation at this site is an excellent marker of NF-κB activation (1-3).

The regulation of IκB-β and IκB-ε is similar to that of IκB-α. However, the phosphorylation and ubiquitin-mediated degradation of these proteins occurs with much slower kinetics (9). IKK phosphorylation of IκB-β occurs at Ser19 and Ser23, while IκB-ε 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

Have you published research involving the use of our products? If so we'd love to hear about it. Please let us know!

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.

Product Pathways

Drug Discovery Tools

Featured Technologies

Protein Classes