Structural basis of steroid hormone perception by the receptor kinase BRI1

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Abstract

Polyhydroxylated steroids are regulators of body shape and size in higher organisms. In metazoans, intracellular receptors recognize these molecules. Plants, however, perceive steroids at membranes, using the membrane-integral receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1). Here we report the structure of the Arabidopsis thaliana BRI1 ligand-binding domain, determined by X-ray diffraction at 2.5 Å resolution. We find a superhelix of 25 twisted leucine-rich repeats (LRRs), an architecture that is strikingly different from the assembly of LRRs in animal Toll-like receptors. A 70-amino-acid island domain between LRRs 21 and 22 folds back into the interior of the superhelix to create a surface pocket for binding the plant hormone brassinolide. Known loss- and gain-of-function mutations map closely to the hormone-binding site. We propose that steroid binding to BRI1 generates a docking platform for a co-receptor that is required for receptor activation. Our findings provide insight into the activation mechanism of this highly expanded family of plant receptors that have essential roles in hormone, developmental and innate immunity signalling.

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Figure 1: The BRI1 ectodomain forms a superhelix.
Figure 2: Plant-specific sequence fingerprints cause the superhelical arrangement.
Figure 3: The steroid hormone binding site maps to the C-terminal inner surface of the superhelix.
Figure 4: An accessible membrane-proximal region of BRI1 may provide a protein–protein interaction platform.

Accession codes

Primary accessions

Protein Data Bank

Data deposits

Atomic coordinates and structure factors for the reported crystal structures have been deposited in the Protein Data Bank under accession numbers 3RIZ for the unliganded BRI1 ectodomain and 3RJ0 for the BRI1–brassinolide complex.

References

  1. 1

    Shiu, S. H. & Bleecker, A. B. Receptor-like kinases from Arabidopsis form a monophyletic gene family related to animal receptor kinases. Proc. Natl Acad. Sci. USA 98, 10763–10768 (2001)

  2. 2

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

  3. 3

    Clark, S. E., Williams, R. W. & Meyerowitz, E. M. The CLAVATA1 gene encodes a putative receptor kinase that controls shoot and floral meristem size in Arabidopsis . Cell 89, 575–585 (1997)

  4. 4

    Nadeau, J. A. & Sack, F. D. Control of stomatal distribution on the Arabidopsis leaf surface. Science 296, 1697–1700 (2002)

  5. 5

    Gómez-Gómez, L. & Boller, T. FLS2: an LRR receptor-like kinase involved in the perception of the bacterial elicitor flagellin in Arabidopsis . Mol. Cell 5, 1003–1011 (2000)

  6. 6

    Nishimura, R. et al. HAR1 mediates systemic regulation of symbiotic organ development. Nature 420, 426–429 (2002)

  7. 7

    Wang, Z. Y., Seto, H., Fujioka, S., Yoshida, S. & Chory, J. BRI1 is a critical component of a plasma-membrane receptor for plant steroids. Nature 410, 380–383 (2001)

  8. 8

    Ogawa, M., Shinohara, H., Sakagami, Y. & Matsubayashi, Y. Arabidopsis CLV3 peptide directly binds CLV1 ectodomain. Science 319, 294 (2008)

  9. 9

    Belkhadir, Y. & Chory, J. Brassinosteroid signaling: a paradigm for steroid hormone signaling from the cell surface. Science 314, 1410–1411 (2006)

  10. 10

    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)

  11. 11

    Mangelsdorf, D. J. et al. The nuclear receptor superfamily: the second decade. Cell 83, 835–839 (1995)

  12. 12

    Geldner, N., Hyman, D. L., Wang, X., Schumacher, K. & Chory, J. Endosomal signaling of plant steroid receptor kinase BRI1. Genes Dev. 21, 1598–1602 (2007)

  13. 13

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

  14. 14

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

  15. 15

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

  16. 16

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

  17. 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)

  18. 18

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

  19. 19

    Chinchilla, D., Shan, L., He, P., de Vries, S. & Kemmerling, B. One for all: the receptor-associated kinase BAK1. Trends Plant Sci. 14, 535–541 (2009)

  20. 20

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

  21. 21

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

  22. 22

    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)

  23. 23

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

  24. 24

    Choe, J., Kelker, M. S. & Wilson, I. A. Crystal structure of human toll-like receptor 3 (TLR3) ectodomain. Science 309, 581–585 (2005)

  25. 25

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

  26. 26

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

  27. 27

    Bella, J., Hindle, K. L., McEwan, P. A. & Lovell, S. C. The leucine-rich repeat structure. Cell. Mol. Life Sci. 65, 2307–2333 (2008)

  28. 28

    Evdokimov, A. G., Anderson, D. E., Routzahn, K. M. & Waugh, D. S. Unusual molecular architecture of the Yersinia pestis cytotoxin YopM: a leucine-rich repeat protein with the shortest repeating unit. J. Mol. Biol. 312, 807–821 (2001)

  29. 29

    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)

  30. 30

    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)

  31. 31

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

  32. 32

    Noguchi, T. et al. Brassinosteroid-insensitive dwarf mutants of Arabidopsis accumulate brassinosteroids. Plant Physiol. 121, 743–752 (1999)

  33. 33

    Jin, H., Yan, Z., Nam, K. H. & Li, J. Allele-specific suppression of a defective brassinosteroid receptor reveals a physiological role of UGGT in ER quality control. Mol. Cell 26, 821–830 (2007)

  34. 34

    Fujioka, S. et al. The Arabidopsis deetiolated2 mutant is blocked early in brassinosteroid biosynthesis. Plant Cell 9, 1951–1962 (1997)

  35. 35

    Back, T. G. & Pharis, R. P. Structure-activity studies of brassinosteroids and the search for novel analogues and mimetics with improved bioactivity. J. Plant Growth Regul. 22, 350–361 (2003)

  36. 36

    Diévart, A., Hymes, M. J., Li, J. & Clark, S. E. Brassinosteroid-independent function of BRI1/CLV1 chimeric receptors. Funct. Plant Biol. 33, 723–730 (2006)

  37. 37

    Gruszka, D., Szarejko, I. & Maluszynski, M. New allele of HvBRI1 gene encoding brassinosteroid receptor in barley. J. Appl. Genet. (published online, 10.1007/s13353-011-0031-7 8 February 2011)

  38. 38

    Friedrichsen, D. M., Joazeiro, C. A., Li, J., Hunter, T. & Chory, J. Brassinosteroid-insensitive-1 is a ubiquitously expressed leucine-rich repeat receptor serine/threonine kinase. Plant Physiol. 123, 1247–1256 (2000)

  39. 39

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

  40. 40

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

  41. 41

    Han, B. W., Herrin, B. R., Cooper, M. D. & Wilson, I. A. Antigen recognition by variable lymphocyte receptors. Science 321, 1834–1837 (2008)

  42. 42

    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)

  43. 43

    He, K. et al. BAK1 and BKK1 regulate brassinosteroid-dependent growth and brassinosteroid-independent cell-death pathways. Curr. Biol. 17, 1109–1115 (2007)

  44. 44

    Karlova, R. et al. The Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1 protein complex includes BRASSINOSTEROID-INSENSITIVE1. Plant Cell 18, 626–638 (2006)

  45. 45

    Kabsch, W. Automatic processing of rotation diffraction data from crystals of initially unknown symmetry and cell constants. J. Appl. Crystallogr. 26, 795–800 (1993)

  46. 46

    Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. A 64, 112–122 (2008)

  47. 47

    Bricogne, G., Vonrhein, C., Flensburg, C., Schiltz, M. & Paciorek, W. Generation, representation and flow of phase information in structure determination: recent developments in and around SHARP 2.0. Acta Crystallogr. D 59, 2023–2030 (2003)

  48. 48

    Terwilliger, T. C. et al. Iterative model building, structure refinement and density modification with the PHENIX AutoBuild wizard. Acta Crystallogr. D 64, 61–69 (2008)

  49. 49

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

  50. 50

    Davis, I. W. et al. MolProbity: all-atom contacts and structure validation for proteins and nucleic acids. Nucleic Acids Res. 35, W375–W383 (2007)

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Acknowledgements

We thank J. Vanhnasy and W. Yu for maintaining insect cell stocks, M. Jinek and B. W. Han for advice, W. Kwiatowski for maintenance of the Salk X-ray equipment, Y. Jaillais for discussion, and F. V. Chisari for encouragement and support. This work was supported by the Howard Hughes Medical Institute and a grant from the National Science Foundation (IOS-0649389) to J.C. M.H. was supported by long-term fellowships from the European Molecular Biology Organisation and the International Human Frontier Science Program Organisation. Y.B. was a Howard Hughes Medical Institute fellow of the Life Sciences Research Foundation and also received support from the Philippe Foundation. I.A.W. was supported by NIH grant AI042266 and by the Skaggs Institute for Chemical Biology.

Author information

M.H., Y.B., J.P.N. and J.C. designed the project. M.H. expressed the BRI1 ectodomain in the laboratory of I.A.W. with initial help from Y.B. M.H. purified and crystallized the protein, and phased and refined the structures. M.D. determined viral titres and optimized production of viruses. T.D. cloned the modified transfer vector. M.H., I.A.W. and J.C. analysed the data. J.C. supervised the project. M.H. wrote the paper with input from the other authors.

Correspondence to Joanne Chory.

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Hothorn, M., Belkhadir, Y., Dreux, M. et al. Structural basis of steroid hormone perception by the receptor kinase BRI1. Nature 474, 467–471 (2011) doi:10.1038/nature10153

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