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Auxin-Binding Protein 1 is a negative regulator of the SCFTIR1/AFB pathway

2013; Nature Portfolio; Volume: 4; Issue: 1 Linguagem: Inglês

10.1038/ncomms3496

2041-1723

Alexandre Tromas, Sébastien Paque, Vérène Stierlé, Anne‐Laure Quettier, Philippe Muller, Esther Lechner, Pascal Genschik, Catherine Perrot‐Rechenmann,

Plant-Microbe Interactions and Immunity

Auxin is a major plant hormone that controls most aspects of plant growth and development. Auxin is perceived by two distinct classes of receptors: transport inhibitor response 1 (TIR1, or auxin-related F-box (AFB)) and auxin/indole-3-acetic acid (AUX/IAA) coreceptors, that control transcriptional responses to auxin, and the auxin-binding protein 1 (ABP1), that controls a wide variety of growth and developmental processes. To date, the mode of action of ABP1 is still poorly understood and its functional interaction with TIR1/AFB-AUX/IAA coreceptors remains elusive. Here we combine genetic and biochemical approaches to gain insight into the integration of these two pathways. We find that ABP1 is genetically upstream of TIR1/AFBs; ABP1 knockdown leads to an enhanced degradation of AUX/IAA repressors, independently of its effects on endocytosis, through the SCF(TIR1/AFB) E3 ubiquitin ligase pathway. Combining positive and negative regulation of SCF ubiquitin-dependent pathways might be a common mechanism conferring tight control of hormone-mediated responses.