Molecular and functional characterization of Arabidopsis Cullin 3A

Monika Dieterle, Alexis Thomann, Jean Pierre Renou, Yves Parmentier, Valerie Cognat, Gaetan Lemonnier, Rebecca Müller, Wen Hui Shen, Thomas Kretsch, Pascal Genschik*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

82 Citations (Scopus)

Abstract

Cullin proteins, which belong to multigenic families in all eukaryotes, associate with other proteins to form ubiquitin protein ligases (E3s) that target substrates for proteolysis by the 26S proteasome. Here, we present the molecular and genetic characterization of a plant Cullin3. In contrast to fungi and animals, the genome of the model plant Arabidopsis thaliana contains two related CUL3 genes, called CUL3A and CUL3B. We found that CUL3A is ubiquitously expressed in plants and is able to interact with the ring-finger protein RBX1. A genomic search revealed the existence of at least 76 BTB-domain proteins in Arabidopsis belonging to 11 major families. Yeast two-hybrid experiments indicate that representative members of certain families are able to physically interact with both CUL3A and CUL3B, suggesting that Arabidopsis CUL3 forms E3 protein complexes with certain BTB domain proteins. In order to determine the function of CUL3A, we used a reverse genetic approach. The cul3a null mutant flowers slightly later than the control plants. Furthermore, this mutant exhibits a reduced sensitivity of the inhibition of hypocotyl growth in far-red light and miss-expresses COP1. The viability of the mutant plants suggests functional redundancy between the two CUL3 genes in Arabidopsis.

Original languageEnglish
Pages (from-to)386-399
Number of pages14
JournalPlant Journal
Volume41
Issue number3
DOIs
Publication statusPublished - Feb 2005
Externally publishedYes

Keywords

  • BTB proteins
  • E3 ubiquitin ligase
  • Light signalling
  • Ubiquitin-dependent proteolysis

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