New England Biolabs Canada

Product Pathways - NF-kB Signaling

Phospho-IRF-3 (Ser396) (4D4G) Rabbit mAb #4947

Item# Description List Price Web Price Qty
4947S Phospho-IRF-3 (Ser396) (4D4G) Rabbit mAb - 100 µl $433.00
*On-line ordering is for Canadian customers only. Web pricing is applicable only to orders placed online at
Application Dilution Species-Reactivity Sensitivity MW (kDa) Isotype
W Human, Mouse Endogenous 45-55 Rabbit IgG

Species cross-reactivity is determined by western blot.

Applications Key: W=Western Blotting


Species predicted to react based on 100% sequence homology: Monkey, Pig.


Specificity / Sensitivity

Phospho-IRF-3 (Ser396) (4D4G) Rabbit mAb detects endogenous levels of IRF-3 when phosphorylated at Ser396.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser396 of human IRF-3.

Western Blotting

Western Blotting

Western blot analysis of extracts from HT29 and THP1 cells, control or plpC-transfected (1 hour), using Phospho-IRF-3 (Ser396) (4D4G) Rabbit mAb.


Interferon regulatory factors (IRFs) comprise a family of transcription factors that function within the Jak/Stat pathway to regulate interferon (IFN) and IFN-inducible gene expression in response to viral infection (1). IRFs play an important role in pathogen defense, autoimmunity, lymphocyte development, cell growth, and susceptibility to transformation. The IRF family includes nine members: IRF-1, IRF-2, IRF-9/ISGF3γ, IRF-3, IRF-4 (Pip/LSIRF/ICSAT), IRF-5, IRF-6, IRF-7, and IRF-8/ICSBP. All IRF proteins share homology in their amino-terminal DNA-binding domains. IRF family members regulate transcription through interactions with proteins that share similar DNA-binding motifs, such as IFN-stimulated response elements (ISRE), IFN consensus sequences (ICS), and IFN regulatory elements (IRF-E) (2).

IRF-3 can inhibit cell growth and plays a critical role in controlling the expression of genes in the innate immune response (1-4). In unstimulated cells, IRF-3 is present in the cytoplasm. Viral infection results in phosphorylation of IRF-3 and leads to its translocation to the nucleus where it activates promoters containing IRF-3-binding sites. Phosphorylation of IRF-3 occurs at a cluster of C-terminal serine and threonine residues (between 385 and 405) leading to its association with the p300/CBP coactivator protein that promotes DNA binding and transcriptional activity (5). During infection, IRF-3 is likely activated through a pathway that includes activation of Toll-like receptors and of a kinase complex that includes IKKε and TBK1 (6,7). IRF-3 is phosphorylated at Ser396 following viral infection, expression of viral nucleocapsid, and double stranded RNA treatment. These events likely play a role in activation of IRF-3 (8).

  1. Taniguchi, T. et al. (2001) Annu Rev Immunol 19, 623-55.
  2. Honda, K. and Taniguchi, T. (2006) Nat Rev Immunol 6, 644-58.
  3. Hiscott, J. et al. (1999) J. Interferon Cytokine Res. 19, 1-13.
  4. Kim, T.Y. et al. (2003) J. Biol. Chem. 278, 15272-15278.
  5. Yoneyama, M. et al. (2002) J. Interferon Cytokine Res. 22, 73-76.
  6. Fitzgerald, K.A. et al. (2003) Nat. Immunol. 4, 491-496.
  7. Kopp, E. and Medzhitov, R. (2003) Curr. Opin. Immunol. 15, 396-401.
  8. Servant, M.J. et al. (2003) J. Biol. Chem. 278, 9441-9447.

Application References

  • Johnson, A.C. et al. (2008) J Biol Chem 283, 3988-96. Applications: Western Blotting.
  • Saitoh, T. et al. (2008) Nature 456, 264-8. Applications: Western Blotting.
  • Taura, M. et al. (2008) Mol Cell Biol 28, 6557-67. Applications: Western Blotting.
  • Wilson, J.R. et al. (2008) J Virol 82, 8262-71. Applications: Western Blotting.
  • Yang, P. et al. (2010) Nat Immunol 11, 487-94. Applications: Western Blotting.

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