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

C. Nibau, D. J. Gibbs, K. A. Bunting, L. A. Moody, E. J. Smiles, J. A. Tubby, S. J. Bradshaw, J. C. Coate

Research output: Contribution to journalArticlepeer-review

14 Citations (SciVal)

Abstract

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.
Original languageEnglish
Pages (from-to)77-92
Number of pages16
JournalPlant Molecular Biology
Volume75
Issue number1-2
DOIs
Publication statusPublished - 20 Oct 2010

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