Auxin regulates SCF(TIR1)-dependent degradation of AUX/IAA proteins

Nature. 2001 Nov 15;414(6861):271-6. doi: 10.1038/35104500.


The plant hormone auxin is central in many aspects of plant development. Previous studies have implicated the ubiquitin-ligase SCF(TIR1) 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 SCF(TIR1) decrease auxin response. Here we show that SCF(TIR1) is required for AUX/IAA degradation. We demonstrate that SCF(TIR1) 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 SCF(TIR1) 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Motifs
  • Arabidopsis
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology
  • Gene Expression Regulation, Plant
  • Glucuronidase / genetics
  • Growth Substances*
  • Indoleacetic Acids / genetics
  • Indoleacetic Acids / metabolism*
  • Indoleacetic Acids / physiology*
  • Mutation
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Peptide Synthases / genetics
  • Peptide Synthases / physiology*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Protein Binding
  • Recombinant Fusion Proteins / genetics
  • SKP Cullin F-Box Protein Ligases
  • Transcription Factors
  • Ubiquitin / metabolism


  • AXR1 protein, Arabidopsis
  • AXR3 protein, Arabidopsis
  • Arabidopsis Proteins
  • Growth Substances
  • Indoleacetic Acids
  • Nuclear Proteins
  • Plant Proteins
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Ubiquitin
  • indoleacetic acid
  • SKP Cullin F-Box Protein Ligases
  • Glucuronidase
  • Peptide Synthases