title: Auxin receptors and plant development: a new signaling paradigm.
abstract: The plant hormone auxin, in particular indole-3-acetic acid (IAA), is a key regulator of virtually every aspect of plant growth and development. Auxin regulates transcription by rapidly modulating levels of Aux/IAA proteins throughout development. Recent studies demonstrate that auxin perception occurs through a novel mechanism. Auxin binds to TIR1, the F-box subunit of the ubiquitin ligase complex SCF(TIR1), and stabilizes the interaction between TIR1 and Aux/IAA substrates. This interaction results in Aux/IAA ubiquitination and subsequent degradation. Regulation of the Aux/IAA protein family by TIR1 and TIR1-like auxin receptors (AFBs) links auxin action to transcriptional regulation and provides a model by which the vast array of auxin influences on development may be understood. Moreover, auxin receptor function is the first example of small-molecule regulation of an SCF ubiquitin ligase and may have important implications for studies of regulated protein degradation in other species, including animals.
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405, USA. kmockait@indiana.edu
authors.forename: Keithanne
authors.initials: K
authors.lastname: Mockaitis
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
mesh_terms: D000818:Animals; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism; D044783:F-Box Proteins / Q000737:chemistry / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D008958:Models, Molecular; D063245:Plant Development; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010944:Plants / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D014157:Transcription Factors; D025801:Ubiquitin; C046131:auxin receptor, plant; C030737:indoleacetic acid; D044843:SKP Cullin F-Box Protein Ligases; D046988:Proteasome Endopeptidase Complex