Skip to main content

Thank you for visiting 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.

Structural insight into brassinosteroid perception by BRI1


Brassinosteroids are essential phytohormones that have crucial roles in plant growth and development. Perception of brassinosteroids requires an active complex of BRASSINOSTEROID-INSENSITIVE 1 (BRI1) and BRI1-ASSOCIATED KINASE 1 (BAK1). Recognized by the extracellular leucine-rich repeat (LRR) domain of BRI1, brassinosteroids induce a phosphorylation-mediated cascade to regulate gene expression. Here we present the crystal structures of BRI1(LRR) in free and brassinolide-bound forms. BRI1(LRR) exists as a monomer in crystals and solution independent of brassinolide. It comprises a helical solenoid structure that accommodates a separate insertion domain at its concave surface. Sandwiched between them, brassinolide binds to a hydrophobicity-dominating surface groove on BRI1(LRR). Brassinolide recognition by BRI1(LRR) is through an induced-fit mechanism involving stabilization of two interdomain loops that creates a pronounced non-polar surface groove for the hormone binding. Together, our results define the molecular mechanisms by which BRI1 recognizes brassinosteroids and provide insight into brassinosteroid-induced BRI1 activation.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: BRI1(LRR) has a helical solenoid structure.
Figure 2: Interaction of the insertion domain with LRRs.
Figure 3: Brassinolide binds a hydrophobic groove between the insertion domain and the inner surface of LRRs.
Figure 4: Brassinolide induces stabilization of two interdomain loops but no dimerization of BRI1(LRR).

Accession codes

Primary accessions

Protein Data Bank

Data deposits

The atomic coordinates and structure factors of BRI1(LRR) and the BRI1(LRR)–brassinolide complex have been deposited in the Protein Data Bank under the accession codes 3RGX and 3RGZ, respectively.


  1. Clouse, S. D. & Sasse, J. M. BRASSINOSTEROIDS: essential regulators of plant growth and development. Annu. Rev. Plant Physiol. Plant Mol. Biol. 49, 427–451 (1998)

    Article  CAS  Google Scholar 

  2. Vert, G., Nemhauser, J. L., Geldner, N., Hong, F. & Chory, J. Molecular mechanisms of steroid hormone signaling in plants. Annu. Rev. Cell Dev. Biol. 21, 177–201 (2005)

    Article  CAS  Google Scholar 

  3. Li, J. & Chory, J. A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction. Cell 90, 929–938 (1997)

    Article  CAS  Google Scholar 

  4. Li, J. et al. BAK1, an Arabidopsis LRR receptor-like protein kinase, interacts with BRI1 and modulates brassinosteroid signaling. Cell 110, 213–222 (2002)

    Article  CAS  Google Scholar 

  5. Nam, K. H. & Li, J. BRI1/BAK1, a receptor kinase pair mediating brassinosteroid signaling. Cell 110, 203–212 (2002)

    Article  CAS  Google Scholar 

  6. Li, J. & Nam, K. H. Regulation of brassinosteroid signaling by a GSK3/SHAGGY-like kinase. Science 295, 1299–1301 (2002)

    ADS  CAS  PubMed  Google Scholar 

  7. Sun, Y. et al. Integration of brassinosteroid signal transduction with the transcription network for plant growth regulation in Arabidopsis . Dev. Cell 19, 765–777 (2010)

    Article  CAS  Google Scholar 

  8. Wang, X. & Chory, J. Brassinosteroids regulate dissociation of BKI1, a negative regulator of BRI1 signaling, from the plasma membrane. Science 313, 1118–1122 (2006)

    Article  ADS  CAS  Google Scholar 

  9. Tang, W. et al. BSKs mediate signal transduction from the receptor kinase BRI1 in Arabidopsis . Science 321, 557–560 (2008)

    Article  ADS  CAS  Google Scholar 

  10. Shiu, S. H. et al. Comparative analysis of the receptor-like kinase family in Arabidopsis and rice. Plant Cell 16, 1220–1234 (2004)

    Article  CAS  Google Scholar 

  11. He, Z. et al. Perception of brassinosteroids by the extracellular domain of the receptor kinase BRI1. Science 288, 2360–2363 (2000)

    Article  ADS  CAS  Google Scholar 

  12. Kinoshita, T. et al. Binding of brassinosteroids to the extracellular domain of plant receptor kinase BRI1. Nature 433, 167–171 (2005)

    Article  ADS  CAS  Google Scholar 

  13. Li, J. Brassinosteroid signaling: from receptor kinases to transcription factors. Curr. Opin. Plant Biol. 8, 526–531 (2005)

    Article  CAS  Google Scholar 

  14. Kim, T. W. & Wang, Z. Y. Brassinosteroid signal transduction from receptor kinases to transcription factors. Annu. Rev. Plant Biol. 61, 681–704 (2010)

    Article  CAS  Google Scholar 

  15. Russinova, E. et al. Heterodimerization and endocytosis of Arabidopsis brassinosteroid receptors BRI1 and AtSERK3 (BAK1). Plant Cell 16, 3216–3229 (2004)

    Article  CAS  Google Scholar 

  16. Wang, X. et al. Autoregulation and homodimerization are involved in the activation of the plant steroid receptor BRI1. Dev. Cell 8, 855–865 (2005)

    Article  CAS  Google Scholar 

  17. Wang, X. et al. Identification and functional analysis of in vivo phosphorylation sites of the Arabidopsis BRASSINOSTEROID-INSENSITIVE1 receptor kinase. Plant Cell 17, 1685–1703 (2005)

    Article  CAS  Google Scholar 

  18. Wang, X. et al. Sequential transphosphorylation of the BRI1/BAK1 receptor kinase complex impacts early events in brassinosteroid signaling. Dev. Cell 15, 220–235 (2008)

    Article  CAS  Google Scholar 

  19. J aillais, Y. et al. Tyrosine phosphorylation controls brassinosteroid receptor activation by triggering membrane release of its kinase inhibitor. Genes Dev. 25, 232–237 (2011)

    Article  CAS  Google Scholar 

  20. Kajava, A. V. Structural diversity of leucine-rich repeat proteins. J. Mol. Biol. 277, 519–527 (1998)

    Article  CAS  Google Scholar 

  21. Di Matteo, A. et al. The crystal structure of polygalacturonase-inhibiting protein (PGIP), a leucine-rich repeat protein involved in plant defense. Proc. Natl Acad. Sci. USA 100, 10124–10128 (2003)

    Article  ADS  CAS  Google Scholar 

  22. Hink, M. A., Shah, K., Russinova, E., de Vries, S. C. & Visser, A. J. Fluorescence fluctuation analysis of Arabidopsis thaliana somatic embryogenesis receptor-like kinase and brassinosteroid insensitive 1 receptor oligomerization. Biophys. J. 94, 1052–1062 (2008)

    Article  CAS  Google Scholar 

  23. Zullo, M. T. A. & Adam, G. Brassinosteroid phytohormones—structure, bioactivity and applications. Braz. J. Plant Physiol. 14, 143–181 (2002)

    Article  CAS  Google Scholar 

  24. Li, J., Lease, K. A., Tax, F. E. & Walker, J. C. BRS1, a serine carboxypeptidase, regulates BRI1 signaling in Arabidopsis thaliana . Proc. Natl Acad. Sci. USA 98, 5916–5921 (2001)

    Article  ADS  CAS  Google Scholar 

  25. Liu, L. et al. Structural basis of Toll-like receptor 3 signaling with double-stranded RNA. Science 320, 379–381 (2008)

    Article  ADS  CAS  Google Scholar 

  26. Park, B. S. et al. The structural basis of lipopolysaccharide recognition by the TLR4–MD-2 complex. Nature 458, 1191–1195 (2009)

    Article  ADS  CAS  Google Scholar 

  27. Whippo, C. W. & Hangarter, R. P. A brassinosteroid-hypersensitive mutant of BAK1 indicates that a convergence of photomorphogenic and hormonal signaling modulates phototropism. Plant Physiol. 139, 448–457 (2005)

    Article  CAS  Google Scholar 

  28. Yun, H. S. et al. Analysis of phosphorylation of the BRI1/BAK1 complex in Arabidopsis reveals amino acid residues critical for receptor formation and activation of BR signaling. Mol. Cells 27, 183–190 (2009)

    Article  CAS  Google Scholar 

  29. Sheard, L. B. & Zheng, N. Plant biology: signal advance for abscisic acid. Nature 462, 575–576 (2009)

    Article  ADS  CAS  Google Scholar 

  30. Sheard, L. B. et al. Jasmonate perception by inositol-phosphate-potentiated COI1–JAZ co-receptor. Nature 468, 400–405 (2010)

    Article  ADS  CAS  Google Scholar 

  31. Otwinowski, Z. &. Minor, W. Processing of X-ray diffraction data collected in oscillation mode. Methods Enzymol. 276, 307–326 (1997)

    Article  CAS  Google Scholar 

  32. McCoy, A. J. et al. Phaser crystallographic software. J. Appl. Cryst. 40, 658–674 (2007)

    Article  CAS  Google Scholar 

  33. Schubert, W. D. et al. Structure of internalin, a major invasion protein of Listeria monocytogenes, in complex with its human receptor E-cadherin. Cell 111, 825–836 (2002)

    Article  CAS  Google Scholar 

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

    Article  Google Scholar 

  35. Adams, P. D. et al. PHENIX: building new software for automated crystallographic structure determination. Acta Crystallogr. D 58, 1948–1954 (2002)

    Article  Google Scholar 

  36. DeLano, W. L. PyMOL molecular viewer 〈〉 (2002)

Download references


We thank S. Huang and J. He at Shanghai Synchrotron Radiation Facility (SSRF) for assistance with data collection; J. Chory from the Salk Institute for providing the tritium-labelled brassinolide. This research was funded by the National Outstanding Young Scholar Science Foundation of National Natural Science Foundation of China grant no. 20101331722 to J. Chai and NIH R01GM066258 to Z.-Y.W.

Author information

Authors and Affiliations



J. Chai, Z.H., J.S. and Z.-Y.W. designed the experiments. The binding assay was performed by T.-W.K. and the other assays by J.S., Z.H., Jinjing W., W.C., Jiawei W., M.Y., S.S. and J. Chang. Data were analysed by J. Chai, Z.H., J.S. and Z.-Y.W. J. Chai, Z.-Y.W. and Z.H. wrote the paper.

Corresponding author

Correspondence to Jijie Chai.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

The file contains Supplementary Table 1, Supplementary Figures 1-7 with legends and additional references. (PDF 7395 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

She, J., Han, Z., Kim, TW. et al. Structural insight into brassinosteroid perception by BRI1. Nature 474, 472–476 (2011).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


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.


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