Smad7 binds to the adaptors TAB2 and TAB3 to block recruitment of the kinase TAK1 to the adaptor TRAF2


Transforming growth factor-β1 (TGF-β1) regulates inflammation and can inhibit activation of the transcription factor NF-κB in certain cell types. Here we show that the TGF-β-induced signaling protein Smad7 bound to TAB2 and TAB3, which are adaptors that link the kinase TAK1 to 'upstream' regulators in the proinflammatory tumor necrosis factor (TNF) signaling pathway. Smad7 thereby promoted TGF-β-mediated anti-inflammatory effects. The formation of Smad7-TAB2 and Smad7-TAB3 complexes resulted in the suppression of TNF signaling through the adaptors TRAF2, TAB2 and/or TAB3, and TAK1. Furthermore, expression of a transgene encoding Smad7 in mouse skin suppressed inflammation and NF-κB nuclear translocation substantially and disrupted the formation of endogenous TRAF2-TAK1-TAB2 and TRAF2-TAK1-TAB3 complexes. Thus, Smad7 is a critical mediator of TGF-β signals that block proinflammatory TNF signals.

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Figure 1: Smad7 interacts with TAB2 and TAB3.
Figure 2: Defining the region of Smad7 that interacts with TAB2 and TAB3.
Figure 3: Smad7 does not interfere with the interaction between TAK1 and TAB2 or TAB3.
Figure 4: TGF-β1 and Smad7 inhibit TNF-induced gene expression.
Figure 5: Smad7 interferes with TNF-induced TAK1 activation.
Figure 6: TGF-β1 and Smad7 inhibit the TRAF2-TAK1 interactions.
Figure 7: Smad7 transgene expression attenuated inflammation and NF-κB activation in TPA-treated skin.


  1. 1

    Chen, G. & Goeddel, D.V. TNF-R1 signaling: a beautiful pathway. Science 296, 1634–1635 (2002).

    CAS  Article  Google Scholar 

  2. 2

    Yeh, W.C. et al. Early lethality, functional NF-κB activation, and increased sensitivity to TNF-induced cell death in TRAF2-deficient mice. Immunity 7, 715–725 (1997).

    CAS  Article  Google Scholar 

  3. 3

    Devin, A. et al. The distinct roles of TRAF2 and RIP in IKK activation by TNF-R1: TRAF2 recruits IKK to TNF-R1 while RIP mediates IKK activation. Immunity 12, 419–429 (2000).

    CAS  Article  Google Scholar 

  4. 4

    Pikarsky, E. et al. NF-κB functions as a tumour promoter in inflammation-associated cancer. Nature 431, 461–466 (2004).

    CAS  Article  Google Scholar 

  5. 5

    Luo, J.L., Maeda, S., Hsu, L.C., Yagita, H. & Karin, M. Inhibition of NF-κB in cancer cells converts inflammation-induced tumor growth mediated by TNFα to TRAIL-mediated tumor regression. Cancer Cell 6, 297–305 (2004).

    CAS  Article  Google Scholar 

  6. 6

    Greten, F.R. et al. IKKβ links inflammation and tumorigenesis in a mouse model of colitis-associated cancer. Cell 118, 285–296 (2004).

    CAS  Article  Google Scholar 

  7. 7

    Yamaguchi, K. et al. Identification of a member of the MAPKKK family as a potential mediator of TGF-β signal transduction. Science 270, 2008–2011 (1995).

    CAS  Article  Google Scholar 

  8. 8

    Ninomiya-Tsuji, J. et al. The kinase TAK1 can activate the NIK-IκB as well as the MAP kinase cascade in the IL-1 signalling pathway. Nature 398, 252–256 (1999).

    CAS  Article  Google Scholar 

  9. 9

    Takaesu, G. et al. TAB2, a novel adaptor protein, mediates activation of TAK1 MAPKKK by linking TAK1 to TRAF6 in the IL-1 signal transduction pathway. Mol. Cell 5, 649–658 (2000).

    CAS  Article  Google Scholar 

  10. 10

    Ishitani, T. et al. Role of the TAB2-related protein TAB3 in IL-1 and TNF signaling. EMBO J. 22, 6277–6288 (2003).

    CAS  Article  Google Scholar 

  11. 11

    Massague, J., Seoane, J. & Wotton, D. Smad transcription factors. Genes Dev. 19, 2783–2810 (2005).

    CAS  Article  Google Scholar 

  12. 12

    Wrana, J.L. et al. TGF β signals through a heteromeric protein kinase receptor complex. Cell 71, 1003–1014 (1992).

    CAS  Article  Google Scholar 

  13. 13

    Yoshimura, A., Mori, H., Ohishi, M., Aki, D. & Hanada, T. Negative regulation of cytokine signaling influences inflammation. Curr. Opin. Immunol. 15, 704–708 (2003).

    CAS  Article  Google Scholar 

  14. 14

    Wang, W. et al. Signaling mechanism of TGF-β1 in prevention of renal inflammation: role of Smad7. J. Am. Soc. Nephrol. 16, 1371–1383 (2005).

    CAS  Article  Google Scholar 

  15. 15

    Geiser, A.G. et al. Transforming growth factor β1 (TGF-β1) controls expression of major histocompatibility genes in the postnatal mouse: aberrant histocompatibility antigen expression in the pathogenesis of the TGF-β1 null mouse phenotype. Proc. Natl. Acad. Sci. USA 90, 9944–9948 (1993).

    CAS  Article  Google Scholar 

  16. 16

    Hayashi, H. et al. The MAD-related protein Smad7 associates with the TGF-β receptor and functions as an antagonist of TGF-β signaling. Cell 89, 1165–1173 (1997).

    CAS  Article  Google Scholar 

  17. 17

    Von Gersdorff, G. et al. Smad3 and Smad4 mediate transcriptional activation of the human Smad7 promoter by transforming growth factor β. J. Biol. Chem. 275, 11320–11326 (2000).

    CAS  Article  Google Scholar 

  18. 18

    Ulloa, L., Doody, J. & Massague, J. Inhibition of transforming growth factor-β/SMAD signalling by the interferon-γ/STAT pathway. Nature 397, 710–713 (1999).

    CAS  Article  Google Scholar 

  19. 19

    Benus, G.F. et al. Inhibition of the transforming growth factor β (TGF-β) pathway by interleukin-1β is mediated through TGF-β-activated kinase 1 phosphorylation of SMAD3. Mol. Biol. Cell 16, 3501–3510 (2005).

    CAS  Article  Google Scholar 

  20. 20

    Pulaski, L., Landstrom, M., Heldin, C.H. & Souchelnytskyi, S. Phosphorylation of Smad7 at Ser-249 does not interfere with its inhibitory role in transforming growth factor-β-dependent signaling but affects Smad7-dependent transcriptional activation. J. Biol. Chem. 276, 14344–14349 (2001).

    CAS  Article  Google Scholar 

  21. 21

    Mazars, A. et al. Evidence for a role of the JNK cascade in Smad7-mediated apoptosis. J. Biol. Chem. 276, 36797–36803 (2001).

    CAS  Article  Google Scholar 

  22. 22

    Lallemand, F. et al. Smad7 inhibits the survival nuclear factor κB and potentiates apoptosis in epithelial cells. Oncogene 20, 879–884 (2001).

    CAS  Article  Google Scholar 

  23. 23

    Karin, M. & Ben Neriah, Y. Phosphorylation meets ubiquitination: the control of NF-κB activity. Annu. Rev. Immunol. 18, 621–663 (2000).

    CAS  Article  Google Scholar 

  24. 24

    Choi, K.-C. et al. Smad6 negatively regulates interleukin 1 receptor–Toll-like receptor signaling through direct interaction with the adaptor Pellino-1. Nat. Immunol. 7, 1057–1065 (2006).

    CAS  Article  Google Scholar 

  25. 25

    Hanafusa, H. et al. Involvement of the p38 mitogen-activated protein kinase pathway in transforming growth factor-β-induced gene expression. J. Biol. Chem. 274, 27161–27167 (1999).

    CAS  Article  Google Scholar 

  26. 26

    Baud, V. et al. Signaling by proinflammatory cytokines: oligomerization of TRAF2 and TRAF6 is sufficient for JNK and IKK activation and target gene induction via an amino-terminal effector domain. Genes Dev. 13, 1297–1308 (1999).

    CAS  Article  Google Scholar 

  27. 27

    Habelhah, H. et al. Ubiquitination and translocation of TRAF2 is required for activation of JNK but not of p38 or NF-κB. EMBO J. 23, 322–332 (2004).

    CAS  Article  Google Scholar 

  28. 28

    Xia, Z.P. & Chen, Z.J. TRAF2: a double-edged sword? Sci. STKE 2005, e7 (2005).

    Google Scholar 

  29. 29

    Li, H., Kobayashi, M., Blonska, M., You, Y. & Lin, X. Ubiquitination of RIP is required for tumor necrosis factor α-induced NF-κB activation. J. Biol. Chem. 281, 13636–13643 (2006).

    CAS  Article  Google Scholar 

  30. 30

    He, W. et al. Overexpression of Smad7 results in severe pathological alterations in multiple epithelial tissues. EMBO J. 21, 2580–2590 (2002).

    CAS  Article  Google Scholar 

  31. 31

    Schiffer, M. et al. Apoptosis in podocytes induced by TGF-β and Smad7. J. Clin. Invest. 108, 807–816 (2001).

    CAS  Article  Google Scholar 

  32. 32

    Takaesu, G. et al. TAB2, a novel adaptor protein, mediates activation of TAK1 MAPKKK by linking TAK1 to TRAF6 in the IL-1 signal transduction pathway. Mol. Cell 5, 649–658 (2000).

    CAS  Article  Google Scholar 

  33. 33

    Tada, K. et al. Critical roles of TRAF2 and TRAF5 in tumor necrosis factor-induced NF-κB activation and protection from cell death. J. Biol. Chem. 276, 36530–36534 (2001).

    CAS  Article  Google Scholar 

  34. 34

    Kelliher, M.A. et al. The death domain kinase RIP mediates the TNF-induced NF-κB signal. Immunity 8, 297–303 (1998).

    CAS  Article  Google Scholar 

  35. 35

    Vodovotz, Y. et al. Spontaneously increased production of nitric oxide and aberrant expression of the inducible nitric oxide synthase in vivo in the transforming growth factor β1 null mouse. J. Exp. Med. 183, 2337–2342 (1996).

    CAS  Article  Google Scholar 

  36. 36

    McCartney-Francis, N.L. & Wahl, S.M. Dysregulation of IFN-γ signaling pathways in the absence of TGF-β1. J. Immunol. 169, 5941–5947 (2002).

    CAS  Article  Google Scholar 

  37. 37

    Li, Q. & Verma, I.M. NF-κB regulation in the immune system. Nat. Rev. Immunol. 2, 725–734 (2002).

    CAS  Article  Google Scholar 

  38. 38

    Jobin, C. & Sartor, R.B. The IκB/NF-κB system: a key determinant of mucosalinflammation and protection. Am. J. Physiol. Cell Physiol. 278, C451–C462 (2000).

    CAS  Article  Google Scholar 

  39. 39

    Handel, M.L., McMorrow, L.B. & Gravallese, E.M. Nuclear factor-κB in rheumatoid synovium. Localization of p50 and p65. Arthritis Rheum. 38, 1762–1770 (1995).

    CAS  Article  Google Scholar 

  40. 40

    Han, S.H., Yea, S.S., Jeon, Y.J., Yang, K.H. & Kaminski, N.E. Transforming growth factor-β1 (TGF-β1) promotes IL-2 mRNA expression through the up-regulation of NF-κB, AP-1 and NF-AT in EL4 cells. J. Pharmacol. Exp. Ther. 287, 1105–1112 (1998).

    CAS  PubMed  Google Scholar 

  41. 41

    Sovak, M.A., Arsura, M., Zanieski, G., Kavanagh, K.T. & Sonenshein, G.E. The inhibitory effects of transforming growth factor β1 on breast cancer cell proliferation are mediated through regulation of aberrant nuclear factor-κB/Rel expression. Cell Growth Differ. 10, 537–544 (1999).

    CAS  PubMed  Google Scholar 

  42. 42

    Arsura, M., Wu, M. & Sonenshein, G.E. TGF beta 1 inhibits NF-κB/Rel activity inducing apoptosis of B cells: transcriptional activation of IκBα. Immunity 5, 31–40 (1996).

    CAS  Article  Google Scholar 

  43. 43

    Monteleone, G. et al. Blocking Smad7 restores TGF-β1 signaling in chronic inflammatory bowel disease. J. Clin. Invest. 108, 601–609 (2001).

    CAS  Article  Google Scholar 

  44. 44

    Dong, C. et al. Deficient Smad7 expression: a putative molecular defect in scleroderma. Proc. Natl. Acad. Sci. USA 99, 3908–3913 (2002).

    CAS  Article  Google Scholar 

  45. 45

    Asano, Y., Ihn, H., Yamane, K., Kubo, M. & Tamaki, K. Impaired Smad7-Smurf-mediated negative regulation of TGF-β signaling in scleroderma fibroblasts. J. Clin. Invest. 113, 253–264 (2004).

    CAS  Article  Google Scholar 

  46. 46

    Landstrom, M. et al. Smad7 mediates apoptosis induced by transforming growth factor β in prostatic carcinoma cells. Curr. Biol. 10, 535–538 (2000).

    CAS  Article  Google Scholar 

  47. 47

    Romieu-Mourez, R., Landesman-Bollag, E., Seldin, D.C. & Sonenshein, G.E. Protein kinase CK2 promotes aberrant activation of nuclear factor-κB, transformed phenotype, and survival of breast cancer cells. Cancer Res. 62, 6770–6778 (2002).

    CAS  PubMed  Google Scholar 

  48. 48

    Xavier, S. et al. Amelioration of radiation-induced fibrosis: inhibition of transforming growth factor-β signaling by halofuginone. J. Biol. Chem. 279, 15167–15176 (2004).

    CAS  Article  Google Scholar 

  49. 49

    Gross, D.J. et al. Treatment with halofuginone results in marked growth inhibition of a von Hippel-Lindau pheochromocytoma in vivo. Clin. Cancer Res. 9, 3788–3793 (2003).

    CAS  PubMed  Google Scholar 

  50. 50

    Lee, B.I. et al. MS-275, a histone deacetylase inhibitor, selectively induces transforming growth factor β type II receptor expression in human breast cancer cells. Cancer Res. 61, 931–942 (2001).

    CAS  PubMed  Google Scholar 

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We thank A. Roberts, G. Merlino and A. Hobbie for the critical reading of the manuscript; J.L. Wrana (University of Toronto) for plasmids expressing Smad7; K. Miyazono (University of Tokyo) for adenovirus expressing Smad7; and C.J. Hastie (University of Dundee) for the TAB3-specific antibody S81B. Supported by the Intramural Research Program of the National Cancer Institute, the National Institutes of Health (X.-J.W.) and the Korea Research Foundation (funded by the Korean Government; KRF-2003-015-C00528 and R08-2003-000-10077-0 to S.H.P).

Author information




S.H., S.L. and C.L. did experimental work and analyzed data; A.G.L. and X.-J.W. developed the K5.Smad7 mice and did the skin inflammation study; Y.S.L., E.-K.L. and S.H.P. did the primary peritoneal macrophage study; S.H.P. participated in study design; S.-J.K. designed and conceptualized the research and supervised the experimental work; and S.H. and S.-J.K. analyzed data and wrote the manuscript.

Corresponding author

Correspondence to Seong-Jin Kim.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Fig. 1

C-terminal region of Smad7 binds to TAB2. (PDF 99 kb)

Supplementary Fig. 2

Smad7 inhibits the activation of NF-κB. (PDF 133 kb)

Supplementary Fig. 3

TGF-β1 inhibits TNF-induced gene expression through Smad7. (PDF 78 kb)

Supplementary Fig. 4

Inhibition of endogenous Smad7 reduces the suppressive effect of TGF-β1 on TNF-induced IKK activity. (PDF 110 kb)

Supplementary Fig. 5

Smad7 does not block the oligomerization of TRAF2 and TRAF5. (PDF 72 kb)

Supplementary Fig. 6

Smad7 does not modulate the ubiquitination of RIP1. (PDF 65 kb)

Supplementary Fig. 7

Smad7 blocks the interaction of TAK1 and TRAF5. (PDF 136 kb)

Supplementary Fig. 8

Smad7C-M3 failed to suppress TRAF2–TAB2- or TRAF2–TAB3-induced IKK activity (PDF 104 kb)

Supplementary Fig. 9

Schematic diagram of crosstalk between TGF-β1 and TNF signaling. (PDF 65 kb)

Supplementary Table

Primer sequences for quantitative RT-PCR. (PDF 45 kb)

Supplementary Methods (PDF 95 kb)

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Hong, S., Lim, S., Li, A. et al. Smad7 binds to the adaptors TAB2 and TAB3 to block recruitment of the kinase TAK1 to the adaptor TRAF2. Nat Immunol 8, 504–513 (2007).

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