title: Characterization of a novel temperature-sensitive allele of the CUL1/AXR6 subunit of SCF ubiquitin-ligases.
abstract: Selective protein degradation by the ubiquitin-proteasome pathway has emerged as a key regulatory mechanism in a wide variety of cellular processes. The selective components of this pathway are the E3 ubiquitin-ligases which act downstream of the ubiquitin-activating and -conjugating enzymes to identify specific substrates for ubiquitinylation. SCF-type ubiquitin-ligases are the most abundant class of E3 enzymes in Arabidopsis. In a genetic screen for enhancers of the tir1-1 auxin response defect, we identified eta1/axr6-3, a recessive and temperature-sensitive mutation in the CUL1 core component of the SCF(TIR1) complex. The axr6-3 mutation interferes with Skp1 binding, thus preventing SCF complex assembly. axr6-3 displays a pleiotropic phenotype with defects in numerous SCF-regulated pathways including auxin signaling, jasmonate signaling, flower development, and photomorphogenesis. We used axr6-3 as a tool for identifying pathways likely to be regulated by SCF-mediated proteolysis and propose new roles for SCF regulation of the far-red light/phyA and sugar signaling pathways. The recessive inheritance and the temperature-sensitive nature of the pleiotropically acting axr6-3 mutation opens promising possibilities for the identification and investigation of SCF-regulated pathways in Arabidopsis.
authors.affiliation: Department of Plant Biology, University of Minnesota-Twin Cities, St Paul, MN 55108, USA.
authors.forename: Marcel
authors.initials: M
authors.lastname: Quint
authors.forename: Hironori
authors.initials: H
authors.lastname: Ito
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.forename: William M
authors.initials: WM
authors.lastname: Gray
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050260:Carbohydrate Metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D044842:Cullin Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006863:Hydrogen-Ion Concentration; D047468:Immunoprecipitation; D007210:Indoleacetic Acids / Q000378:metabolism; D007700:Kinetics; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D007210:Indoleacetic Acids; D044843:SKP Cullin F-Box Protein Ligases