Cell Signaling Technology

Product Pathways - NF-kB Signaling

MDA-5 (R470) Antibody #4110

Applications Reactivity Sensitivity MW (kDa) Source
W IP H Endogenous 135 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
Reactivity Key:  H=Human
Species cross-reactivity is determined by Western blot.

Protocols

Specificity / Sensitivity

MDA-5 (R470) Antibody detects endogenous levels of total MDA-5 protein.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrouding Arg470 of human MDA-5. Antibody is purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot anlaysis of extracts from differentiated THP-1 cells, untreated (-) or treated with LPS (1 μg/ml, overnight), using MDA-5 (R470) Antibody.

Western Blotting

Western Blotting

Western blot analysis of extracts from COS-7 cells, untransfected (-) or transfected with human MDA-5, using MDA-5 (R470) Antibody.

Background

Antiviral innate immunity depends on the combination of parallel pathways triggered by virus detecting proteins in the Toll-like receptor (TLR) family and RNA helicases, such as Rig-I (retinoic acid-inducible gene I) and MDA-5 (melanoma differentiation-associated antigen 5), which promote the transcription of type I interferons (IFN) and antiviral enzymes (1-3). TLRs and helicase proteins contain sites that recognize the molecular patterns of different virus types, including DNA, single-stranded (ssRNA), double-stranded (dsRNA), and glycoproteins. These antiviral proteins are found in different cell compartments, with TLR proteins (i.e. TLR3, TLR7, TLR8 and TLR9) found on endosomal membranes and helicases localized to the cytoplasm. Rig-I expression is induced by retinoic acid, LPS, IFN, and viral infection (4,5). Both Rig-I and MDA-5 share a DExD/H-box helicase domain that detects viral dsRNA and two amino-terminal caspase recruitment domains (CARD) that are required for triggering downstream signaling (4-7). Rig-I binds both dsRNA and viral ssRNA that contains a 5'-triphosphate end not seen in host RNA (8,9). Though structurally related, Rig-I and MDA-5 detect a distinct set of viruses (10,11). The CARD domain of the helicases, which is sufficient to generate signaling and IFN production, is recruited to the CARD domain of the MAVS/VISA/Cardif/IPS-1 mitochondrial protein, which triggers activation of NF-κB, TBK-1/IKK-ε, and IRF-3/IRF-7 (12-15).

MDA-5 (16,17), also named Ifih1 (interferon induced with helicase C domain 1), RH116 (RNA helicase-DEAD box protein 116) (18), and Helicard (19) is found to be induced by interferon. During apoptosis, MDA-5 is cleaved by caspases, separating the helicase and CARD domains (19). MDA-5 is uniquely activated by picornavirus (20) and measles virus (21).

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  2. Meylan, E. and Tschopp, J. (2006) Mol Cell 22, 561-9.
  3. Thompson, A.J. and Locarnini, S.A. (2007) Immunol Cell Biol 85, 435-45.
  4. Imaizumi, T. et al. (2002) Biochem Biophys Res Commun 292, 274-9.
  5. Zhang, X. et al. (2000) Microb Pathog 28, 267-78.
  6. Yoneyama, M. et al. (2005) J Immunol 175, 2851-8.
  7. Yoneyama, M. et al. (2004) Nat Immunol 5, 730-7.
  8. Hornung, V. et al. (2006) Science 314, 994-7.
  9. Pichlmair, A. et al. (2006) Science 314, 997-1001.
  10. Kato, H. et al. (2006) Nature 441, 101-5.
  11. Childs, K. et al. (2007) Virology 359, 190-200.
  12. Meylan, E. et al. (2005) Nature 437, 1167-72.
  13. Xu, L.G. et al. (2005) Mol Cell 19, 727-40.
  14. Kawai, T. et al. (2005) Nat Immunol 6, 981-8.
  15. Seth, R.B. et al. (2005) Cell 122, 669-82.
  16. Kang, D.C. et al. (2002) Proc Natl Acad Sci U S A 99, 637-42.
  17. Kang, D.C. et al. (2004) Oncogene 23, 1789-800.
  18. Cocude, C. et al. (2003) J Gen Virol 84, 3215-25.
  19. Kovacsovics, M. et al. (2002) Curr Biol 12, 838-43.
  20. Kato, H. et al. (2006) Nature 441, 101-5.
  21. Berghäll, H. et al. (2006) Microbes Infect 8, 2138-44.

Application References

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This product is intended for research purposes only. The product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

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