Characterization of a novel temperature-sensitive allele of the CUL1/AXR6 subunit of SCF ubiquitin-ligases.

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.
Mesh Terms:
Alleles, Arabidopsis, Arabidopsis Proteins, Carbohydrate Metabolism, Cell Cycle Proteins, Cullin Proteins, Gene Expression Regulation, Plant, Hydrogen-Ion Concentration, Immunoprecipitation, Indoleacetic Acids, Kinetics, Mutation, Plant Roots, SKP Cullin F-Box Protein Ligases, Temperature
Plant J.
Date: Aug. 01, 2005
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