Cell Signaling Technology

Product Pathways - NF-kB Signaling

Phospho-IκBβ (Thr19/Ser23) Antibody (Human Specific) #4921

Applications Reactivity Sensitivity MW (kDa) Source
W H (Mk) (Dg) Endogenous 48 to 50 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  Mk=Monkey  Dg=Dog
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-IκBβ (Thr19/Ser23) Antibody detects endogenous levels of human IκBβ only when phosphorylated at threonine 19 and serine 23. This antibody also recognizes phosphorylation at Ser19/Ser23 also reported as the sequence for IκBβ.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues of human IκBβ surrounding Thr19/Ser23. Antibodies are purified by protein A and affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from HT-29 cells treated with TNF-α (#2169, 20 ng/ml) and calyculin A (#9902, 100 nM) for 10 minutes as indicated, using Phospho-IκBβ (Thr19/Ser23) Antibody (upper) or IκBβ Antibody #9248 (lower).

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). The human sequence of IκB-β has also been reported to contain a threonine at position 19 suggesting that phosphorylation could be Thr19/Ser23 (11).

  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.
  11. Lee, J. W. et al. (1995) Mol. Endocrinol. 9, 243-254.

Application References

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Companion Products

For Research Use Only. Not For Use In Diagnostic Procedures.

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