Structural Basis for Oligomerisation of Auxin Transcriptional Regulators
Nanao, M.H., Vinos-Poyo, T., Brunoud, G., Thevenon, E., Mazzoleni, M., Mast, D., Laine, S., Wang, S., Hagen, G., Li, H., Guilfoyle, T.J., Parcy, F., Vernoux, T., Dumas, R.(2014) Nat Commun 5: 3617
- PubMed: 24710426 
- DOI: https://doi.org/10.1038/ncomms4617
- Primary Citation of Related Structures:  
4CHK - PubMed Abstract: 
The plant hormone auxin is a key morphogenetic regulator acting from embryogenesis onwards. Transcriptional events in response to auxin are mediated by the auxin response factor (ARF) transcription factors and the Aux/IAA (IAA) transcriptional repressors. At low auxin concentrations, IAA repressors associate with ARF proteins and recruit corepressors that prevent auxin-induced gene expression. At higher auxin concentrations, IAAs are degraded and ARFs become free to regulate auxin-responsive genes. The interaction between ARFs and IAAs is thus central to auxin signalling and occurs through the highly conserved domain III/IV present in both types of proteins. Here, we report the crystal structure of ARF5 domain III/IV and reveal the molecular determinants of ARF-IAA interactions. We further provide evidence that ARFs have the potential to oligomerize, a property that could be important for gene regulation in response to auxin.
Organizational Affiliation: 
1] European Molecular Biology Laboratory, 6 rue Jules Horowitz, BP 181, Grenoble 38042, France [2] Unit of Virus Host-Cell Interactions, UJF-EMBL-CNRS, UMI 3265, 6 rue Jules Horowitz, Grenoble Cedex 9 38042, France.