Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A dimerization-dependent mechanism drives RAF catalytic activation

Nature volume 461, pages 542–545 (2009)Cite this article

Abstract

The ERK (extracellular signal-regulated kinase) pathway is an evolutionarily conserved signal transduction module that controls cellular growth, differentiation and survival1. Activation of receptor tyrosine kinases (RTKs) by the binding of growth factors initiates GTP loading of RAS, which triggers the initial steps in the activation of the ERK pathway by modulating RAF family kinase function. Once activated, RAF participates in a sequential cascade of phosphorylation events that activate MEK, and in turn ERK. Unbridled signalling through the ERK pathway caused by activating mutations in RTKs, RAS or RAF has been linked to several human cancers2. Of note, one member of the RAF family, BRAF, is the most frequently mutated oncogene in the kinase superfamily3. Not surprisingly, there has been a colossal effort to understand the underlying regulation of this family of kinases. In particular, the process by which the RAF kinase domain becomes activated towards its substrate MEK remains of topical interest. Here, using Drosophila Schneider S2 cells, we demonstrate that RAF catalytic function is regulated in response to a specific mode of dimerization of its kinase domain, which we term the side-to-side dimer. Moreover, we find that the RAF-related pseudo-kinase KSR (kinase suppressor of Ras) also participates in forming side-to-side heterodimers with RAF and can thereby trigger RAF activation. This mechanism provides an elegant explanation for the longstanding conundrum about RAF catalytic activation, and also provides an explanation for the capacity of KSR, despite lacking catalytic function, to directly mediate RAF activation. We also show that RAF side-to-side dimer formation is essential for aberrant signalling by oncogenic BRAF mutants, and identify an oncogenic mutation that acts specifically by promoting side-to-side dimerization. Together, our data identify the side-to-side dimer interface of RAF as a potential therapeutic target for intervention in BRAF-dependent tumorigenesis.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

Buy

All prices are NET prices.

Figure 1: KSR possesses intrinsic RAF activating potential.
Figure 2: KSR and RAF share a conserved side-to-side dimer interface.
Figure 3: Side-to-side dimerization of RAF activates its catalytic function.
Figure 4: Side-to-side dimer formation underlies the aberrant signalling potential of oncogenic RAF mutants.

Accession codes

Primary accessions

Protein Data Bank

References

  1. Wellbrock, C., Karasarides, M. & Marais, R. The RAF proteins take centre stage. Nature Rev. Mol. Cell Biol. 5, 875–885 (2004)

    CAS  Article  Google Scholar 

  2. Roberts, P. J. & Der, C. J. Targeting the Raf-MEK-ERK mitogen-activated protein kinase cascade for the treatment of cancer. Oncogene 26, 3291–3310 (2007)

    CAS  Article  Google Scholar 

  3. Greenman, C. et al. Patterns of somatic mutation in human cancer genomes. Nature 446, 153–158 (2007)

    ADS  CAS  Article  Google Scholar 

  4. Manning, G., Whyte, D. B., Martinez, R., Hunter, T. & Sudarsanam, S. The protein kinase complement of the human genome. Science 298, 1912–1934 (2002)

    ADS  CAS  Article  Google Scholar 

  5. Boudeau, J., Miranda-Saavedra, D., Barton, G. J. & Alessi, D. R. Emerging roles of pseudokinases. Trends Cell Biol. 16, 443–452 (2006)

    CAS  Article  Google Scholar 

  6. Kolch, W. Coordinating ERK/MAPK signalling through scaffolds and inhibitors. Nature Rev. Mol. Cell Biol. 6, 827–837 (2005)

    CAS  Article  Google Scholar 

  7. Douziech, M., Sahmi, M., Laberge, G. & Therrien, M. A. KSR/CNK complex mediated by HYP, a novel SAM domain-containing protein, regulates RAS-dependent RAF activation in Drosophila . Genes Dev. 20, 807–819 (2006)

    CAS  Article  Google Scholar 

  8. Roy, F., Laberge, G., Douziech, M., Ferland-McCollough, D. & Therrien, M. KSR is a scaffold required for activation of the ERK/MAPK module. Genes Dev. 16, 427–438 (2002)

    CAS  Article  Google Scholar 

  9. Roignant, J. Y., Hamel, S., Janody, F. & Treisman, J. E. The novel SAM domain protein Aveugle is required for Raf activation in the Drosophila EGF receptor signaling pathway. Genes Dev. 20, 795–806 (2006)

    CAS  Article  Google Scholar 

  10. Ritt, D. A. et al. CK2 is a component of the KSR1 scaffold complex that contributes to Raf kinase activation. Curr. Biol. 17, 179–184 (2007)

    CAS  Article  Google Scholar 

  11. Wan, P. T. et al. Mechanism of activation of the RAF-ERK signaling pathway by oncogenic mutations of B-RAF. Cell 116, 855–867 (2004)

    CAS  Article  Google Scholar 

  12. King, A. J. et al. Demonstration of a genetic therapeutic index for tumors expressing oncogenic BRAF by the kinase inhibitor SB-590885. Cancer Res. 66, 11100–11105 (2006)

    CAS  Article  Google Scholar 

  13. Tsai, J. et al. Discovery of a selective inhibitor of oncogenic B-Raf kinase with potent antimelanoma activity. Proc. Natl Acad. Sci. USA 105, 3041–3046 (2008)

    ADS  CAS  Article  Google Scholar 

  14. Hansen, J. D. et al. Potent and selective pyrazole-based inhibitors of B-Raf kinase. Bioorg. Med. Chem. Lett. 18, 4692–4695 (2008)

    CAS  Article  Google Scholar 

  15. Huse, M. & Kuriyan, J. The conformational plasticity of protein kinases. Cell 109, 275–282 (2002)

    CAS  Article  Google Scholar 

  16. Dar, A. C., Dever, T. E. & Sicheri, F. Higher-order substrate recognition of eIF2α by the RNA-dependent protein kinase PKR. Cell 122, 887–900 (2005)

    CAS  Article  Google Scholar 

  17. Zhang, X., Gureasko, J., Shen, K., Cole, P. A. & Kuriyan, J. An allosteric mechanism for activation of the kinase domain of epidermal growth factor receptor. Cell 125, 1137–1149 (2006)

    CAS  Article  Google Scholar 

  18. Muthuswamy, S. K., Gilman, M. & Brugge, J. S. Controlled dimerization of ErbB receptors provides evidence for differential signaling by homo- and heterodimers. Mol. Cell. Biol. 19, 6845–6857 (1999)

    CAS  Article  Google Scholar 

  19. Weber, C. K., Slupsky, J. R., Kalmes, H. A. & Rapp, U. R. Active Ras induces heterodimerization of cRaf and BRaf. Cancer Res. 61, 3595–3598 (2001)

    CAS  PubMed  Google Scholar 

  20. Garnett, M. J., Rana, S., Paterson, H., Barford, D. & Marais, R. Wild-type and mutant B-RAF activate C-RAF through distinct mechanisms involving heterodimerization. Mol. Cell 20, 963–969 (2005)

    CAS  Article  Google Scholar 

  21. Rushworth, L. K., Hindley, A. D., O’Neill, E. & Kolch, W. Regulation and role of Raf-1/B-Raf heterodimerization. Mol. Cell. Biol. 26, 2262–2272 (2006)

    CAS  Article  Google Scholar 

  22. Davies, H. et al. Mutations of the BRAF gene in human cancer. Nature 417, 949–954 (2002)

    ADS  CAS  Article  Google Scholar 

  23. Halilovic, E. & Solit, D. B. Therapeutic strategies for inhibiting oncogenic BRAF signaling. Curr. Opin. Pharmacol. 8, 419–426 (2008)

    CAS  Article  Google Scholar 

  24. Schwede, T., Kopp, J., Guex, N. & Peitsch, M. C. SWISS-MODEL: An automated protein homology-modeling server. Nucleic Acids Res. 31, 3381–3385 (2003)

    CAS  Article  Google Scholar 

  25. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

Download references

Acknowledgements

We thank members of the F.S. and M.T. laboratories for advice and discussions. We are also grateful to R. Lambert and IRIC genomic platform for conducting qPCR reactions. This work was supported by grants from the Canadian Institutes for Health Research to F.S. (MOP-36399) and from the Canadian Cancer Society to M.T. (Award 018046). T.R. is a Research Fellow of The Terry Fox Foundation (Award 019684). F.S. is a recipient of a National Cancer Institute of Canada Scientist award, and M.T. is a Canada Research Chair (Tier II) in Intracellular Signaling.

Author Contributions T.R., M.S., F.S. and M.T. designed the study. T.R., M.S. and M.L. performed experiments. T.R. and M.S. analysed experiments. T.R., F.S. and M.T. wrote the paper.

Author information

Author notes

  1. Thanashan Rajakulendran and Malha Sahmi: These authors contributed equally to this work.

Authors and Affiliations

  1. Centre for Systems Biology, Samuel Lunenfeld Research Institute, Toronto, Ontario M5G 1X5, Canada ,

    Thanashan Rajakulendran & Frank Sicheri

  2. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada,

    Thanashan Rajakulendran & Frank Sicheri

  3. Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling,,

    Malha Sahmi, Martin Lefrançois & Marc Therrien

  4. Département de pathologie et de biologie cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada,

    Marc Therrien

Authors
  1. Thanashan Rajakulendran
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Malha Sahmi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Martin Lefrançois
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Frank Sicheri
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Marc Therrien
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding authors

Correspondence to Frank Sicheri or Marc Therrien.

Supplementary information

Supplementary Information

This file contains Supplementary Table 1, Supplementary Figures 1-9 with Legends, Supplementary Methods and Supplementary References. (PDF 3541 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Rajakulendran, T., Sahmi, M., Lefrançois, M. et al. A dimerization-dependent mechanism drives RAF catalytic activation. Nature 461, 542–545 (2009). https://doi.org/10.1038/nature08314

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature08314

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing