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Auxin regulates SCFTIR1-dependent degradation of AUX/IAA proteins

Abstract

The plant hormone auxin is central in many aspects of plant development. Previous studies have implicated the ubiquitin-ligase SCFTIR1 and the AUX/IAA proteins in auxin response. Dominant mutations in several AUX/IAA genes confer pleiotropic auxin-related phenotypes, whereas recessive mutations affecting the function of SCFTIR1 decrease auxin response. Here we show that SCFTIR1 is required for AUX/IAA degradation. We demonstrate that SCFTIR1 interacts with AXR2/IAA7 and AXR3/IAA17, and that domain II of these proteins is necessary and sufficient for this interaction. Further, auxin stimulates binding of SCFTIR1 to the AUX/IAA proteins, and their degradation. Because domain II is conserved in nearly all AUX/IAA proteins in Arabidopsis, we propose that auxin promotes the degradation of this large family of transcriptional regulators, leading to diverse downstream effects.

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Figure 1: Analysis of AUX/IAA–GUS fusion constructs. a, Seven-day-old seedlings stained for GUS activity.
Figure 2: The proteasome inhibitor MG132 increases AUX/IAA protein stability. a, Seven-day-old seedlings were treated with 10 µM MG132 for 2 h and stained for GUS activity.
Figure 3: AUX/IAA proteins exhibit increased stability in axr1 and tir1 mutants.
Figure 4: SCFTIR1 interacts with AUX/IAA proteins. a, Immunoprecipitates (IP) were blotted and probed with the anti-c-myc antibody.
Figure 5: Auxin promotes the SCFTIR1–AUX/IAA interaction.
Figure 6: Model for auxin response.

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References

  1. Gray, W. M. & Estelle, I. Function of the ubiquitin-proteasome pathway in auxin response. Trends Biochem. Sci. 25, 133–138 (2000).

    Article  CAS  Google Scholar 

  2. Gray, W. M. et al. Identification of an SCF ubiquitin-ligase complex required for auxin response in Arabidopsis thaliana. Genes Dev. 13, 1678–1691 (1999).

    Article  CAS  Google Scholar 

  3. Ruegger, M. et al. The TIR1 protein of Arabidopsis functions in auxin response and is related to human SKP2 and yeast grr1p. Genes Dev. 12, 198–207 (1998).

    Article  CAS  Google Scholar 

  4. del Pozo, J. C., Timpte, C., Tan, S., Callis, J. & Estelle, M. The ubiquitin-related protein RUB1 and auxin response in Arabidopsis. Science 280, 1760–1763 (1998).

    Article  ADS  CAS  Google Scholar 

  5. Lyapina, S. et al. Promotion of NEDD8-CUL1 conjugate cleavage by COP9 signalosome. Science 292, 1382–1385 (2001).

    Article  ADS  CAS  Google Scholar 

  6. Osaka, F. et al. Covalent modifier NEDD8 is essential for SCF ubiquitin-ligase in fission yeast. EMBO J. 19, 3475–3484 (2000).

    Article  CAS  Google Scholar 

  7. Podust, V. N. et al. A Nedd8 conjugation pathway is essential for proteolytic targeting of p27Kip1 by ubiquitination. Proc. Natl Acad. Sci. USA 97, 4579–4584 (2000).

    Article  ADS  CAS  Google Scholar 

  8. del Pozo, J. C. & Estelle, M. The Arabidopsis cullin AtCUL1 is modified by the ubiquitin-related protein RUB1. Proc. Natl Acad. Sci. USA 96, 15342–15347 (1999).

    Article  ADS  CAS  Google Scholar 

  9. Abel, S., Nguyen, M. D. & Theologis, A. The PS-IAA4/5-like family of early auxin-inducible mRNAs in Arabidopsis thaliana. J. Mol. Biol. 251, 533–549 (1995).

    Article  CAS  Google Scholar 

  10. Kim, J., Harter, K. & Theologis, A. Protein–protein interactions among the Aux/IAA proteins. Proc. Natl Acad. Sci. USA 94, 11786–11791 (1997).

    Article  ADS  CAS  Google Scholar 

  11. Ulmasov, T., Hagen, G. & Guilfoyle, T. J. ARF1, a transcription factor that binds to auxin response elements. Science 276, 1865–1868 (1997).

    Article  CAS  Google Scholar 

  12. Ulmasov, T., Murfett, J., Hagen, G. & Guilfoyle, T. J. Aux/IAA proteins repress expression of reporter genes containing natural and highly active synthetic auxin response elements. Plant Cell 9, 1963–1971 (1997).

    Article  CAS  Google Scholar 

  13. Nagpal, P. et al. AXR2 encodes a member of the Aux/IAA protein family. Plant Physiol. 123, 563–574 (2000).

    Article  CAS  Google Scholar 

  14. Rogg, L. E., Lasswell, J. & Bartel, B. A gain-of-function mutation in iaa28 suppresses lateral root development. Plant Cell 13, 465–480 (2001).

    Article  CAS  Google Scholar 

  15. Rouse, D., Mackay, P., Stirnberg, P., Estelle, M. & Leyser, O. Changes in auxin response from mutations in an AUX/IAA gene. Science 279, 1371–1373 (1998).

    Article  ADS  CAS  Google Scholar 

  16. Tian, Q. & Reed, J. W. Control of auxin-regulated root development by the Arabidopsis thaliana SHY2/IAA3 gene. Development 126, 711–721 (1999).

    CAS  PubMed  Google Scholar 

  17. Worley, C. K. et al. Degradation of Aux/IAA proteins is essential for normal auxin signalling. Plant J. 21, 553–562 (2000).

    Article  CAS  Google Scholar 

  18. Ouellet, F., Overvoorde, P. J. & Theologis, A. IAA17/AXR3. Biochemical insight into an auxin mutant phenotype. Plant Cell 13, 829–842 (2001).

    Article  CAS  Google Scholar 

  19. Smart, C. M., Scofield, S. R., Bevan, M. W. & Dyer, T. A. Delayed leaf senescence in tobacco plants transformed with TMR, a gene for cytokinin production in Agrobacterium. Plant Cell 3, 647–656 (1991).

    Article  CAS  Google Scholar 

  20. Deshaies, R. J. SCF and Cullin/Ring H2-based ubiquitin ligases. Annu. Rev. Cell Dev. Biol. 15, 435–467 (1999).

    Article  CAS  Google Scholar 

  21. Mockaitis, K. & Howell, S. H. Auxin induces mitogenic activated protein kinase (MAPK) activation in roots of Arabidopsis seedlings. Plant J. 24, 785–796 (2000).

    Article  CAS  Google Scholar 

  22. Ramos, J. A., Zenser, N., Leyser, H. M. & Callis, J. Rapid degradation of Aux/IAA proteins requires conserved amino acids of domain II and is proteasome-dependent. Plant Cell 13, 2349–2360 (2001).

    Article  CAS  Google Scholar 

  23. Ulmasov, T., Hagen, G. & Guilfoyle, T. J. Dimerization and DNA binding of auxin response factors. Plant J. 19, 309–319 (1999).

    Article  CAS  Google Scholar 

  24. Ulmasov, T., Hagen, G. & Guilfoyle, T. J. Activation and repression of transcription by auxin-response factors. Proc. Natl Acad. Sci. USA 96, 5844–5849 (1999).

    Article  ADS  CAS  Google Scholar 

  25. Berleth, T. & Jurgens, G. The role of the monopteros gene in organising the basal body region of the Arabidopsis embryo. Development 118, 575–587 (1993).

    Google Scholar 

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

    Article  CAS  Google Scholar 

  27. Abel, S., Oeller, P. W. & Theologis, A. Early auxin-induced genes encode short-lived nuclear proteins. Proc. Natl Acad. Sci. USA 91, 326–330 (1994).

    Article  ADS  CAS  Google Scholar 

  28. Lincoln, C., Britton, J. H. & Estelle, M. Growth and development of the axr1 mutants of Arabidopsis. Plant Cell 2, 1071–1080 (1990).

    Article  CAS  Google Scholar 

  29. Stomp, A.-M. in GUS Protocols (ed. Gallagher, S. R.) 103–113 (Academic, London, 1991).

    Google Scholar 

  30. Pringle, J. R. et al. Fluorescence microscopy methods for yeast. Methods Cell Biol. 31, 357–435 (1989).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by grants from the National Institutes of Health (M.E.), the US Department of Energy (M.E.), the Texas Higher Education Coordinating Body Advance Research Program (M.E.) and the UK Biotechnology and Biological Science Research Council (O.L.).

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Correspondence to Mark Estelle.

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Gray, W., Kepinski, S., Rouse, D. et al. Auxin regulates SCFTIR1-dependent degradation of AUX/IAA proteins. Nature 414, 271–276 (2001). https://doi.org/10.1038/35104500

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