Plant Molecular Biology

, Volume 75, Issue 1, pp 77–92

ARABIDILLO proteins have a novel and conserved domain structure important for the regulation of their stability


  • Cândida Nibau
    • School of BiosciencesUniversity of Birmingham
    • IBERSAberystwyth University
  • Daniel J. Gibbs
    • School of BiosciencesUniversity of Birmingham
    • Division of Plant and Crop SciencesUniversity of Nottingham
  • Karen A. Bunting
    • Institute of GeneticsUniversity of Nottingham Medical School
  • Laura A. Moody
    • School of BiosciencesUniversity of Birmingham
  • Emma J. Smiles
    • School of BiosciencesUniversity of Birmingham
  • Jennifer A. Tubby
    • School of BiosciencesUniversity of Birmingham
  • Susan J. Bradshaw
    • School of BiosciencesUniversity of Birmingham
    • School of BiosciencesUniversity of Birmingham

DOI: 10.1007/s11103-010-9709-1

Cite this article as:
Nibau, C., Gibbs, D.J., Bunting, K.A. et al. Plant Mol Biol (2011) 75: 77. doi:10.1007/s11103-010-9709-1


ARABIDILLO proteins are F-box-Armadillo (ARM) proteins that regulate root branching in Arabidopsis. Many F-box proteins in plants, yeast and mammals are unstable. In plants, the mechanism for this instability has not been fully investigated. Here, we show that a conserved family of plant ARABIDILLO-related proteins has a unique domain structure consisting of an F-box and leucine-rich repeats (LRRs) followed by ARM-repeats. The LRRs are similar to those found in other plant and animal F-box proteins, including cell cycle proteins and hormone receptors. We demonstrate that the LRRs are required for ARABIDILLO1 function in vivo. ARABIDILLO1 protein is unstable: we show that ARABIDILLO1 protein is associated with ubiquitin and is turned over by the proteasome. Both the F-box and LRR regions of ARABIDILLO1 appear to enable this turnover to occur. Application of known lateral root-regulating signals has no effect on ARABIDILLO1 stability. In addition, plants that lack or overexpress ARABIDILLO proteins respond normally to known lateral root-regulating signals. Thus, we suggest that the signal(s) regulating ARABIDILLO stability in vivo may be either highly specific or novel. The structural conservation between ARABIDILLOs and other plant and animal F-box proteins suggests that the stability of other F-box proteins may be controlled by similar mechanisms.


F-box Armadillo repeats Leucine-rich repeats Protein stability

Supplementary material

11103_2010_9709_MOESM1_ESM.pdf (121 kb)
Supplementary material 1 (PDF 122 kb)
11103_2010_9709_MOESM2_ESM.pdf (11.1 mb)
Supplementary material 2 (PDF 11 MB)

Copyright information

© Springer Science+Business Media B.V. 2010