SCF^TIR1 AFB-auxin signalling regulates PIN vacuolar trafficking and auxin fluxes during root gravitropism Journal Article

Author(s): Baster, Paweł; Robert, Stéphanie; Kleine-Vehn, Jürgen; Vanneste, Steffen; Kania, Urszula; Grunewald, Wim; De Rybel, Bert D; Beeckman, Tom; Friml, Jiří
Article Title: SCF^TIR1 AFB-auxin signalling regulates PIN vacuolar trafficking and auxin fluxes during root gravitropism
Affiliation IST Austria
Abstract: The distribution of the phytohormone auxin regulates many aspects of plant development including growth response to gravity. Gravitropic root curvature involves coordinated and asymmetric cell elongation between the lower and upper side of the root, mediated by differential cellular auxin levels. The asymmetry in the auxin distribution is established and maintained by a spatio-temporal regulation of the PIN-FORMED (PIN) auxin transporter activity. We provide novel insights into the complex regulation of PIN abundance and activity during root gravitropism. We show that PIN2 turnover is differentially regulated on the upper and lower side of gravistimulated roots by distinct but partially overlapping auxin feedback mechanisms. In addition to regulating transcription and clathrin-mediated internalization, auxin also controls PIN abundance at the plasma membrane by promoting their vacuolar targeting and degradation. This effect of elevated auxin levels requires the activity of SKP-Cullin-F-box TIR1/AFB (SCF TIR1/AFB)-dependent pathway. Importantly, also suboptimal auxin levels mediate PIN degradation utilizing the same signalling pathway. These feedback mechanisms are functionally important during gravitropic response and ensure fine-tuning of auxin fluxes for maintaining as well as terminating asymmetric growth.
Keywords: Gravitropism; Auxin; PIN; degradation
Journal Title: EMBO Journal
Volume: 32
Issue 2
ISSN: 1460-2075
Publisher: Wiley-Blackwell  
Date Published: 2013-01-23
Start Page: 260
End Page: 274
Sponsor: This work was supported by the Odysseus program of the Research Foundation Flanders (to JF), the Vienna Science and Technology fund (WWTF) (to JK-V) and Vetenskapsråde and VINNOVA (to SR). SV is a Post-doctoral Fellow of the Research Foundation-Flanders.
DOI: 10.1038/emboj.2012.310
Notes: We thank Mark Estelle (University of California, San Diego, CA, USA), Ottoline Leyser (University of Cambridge, Cambridge, UK), Christian Luschnig (University of Applied Life Sciences and Natural Resources, Vienna, Austria), Remko Offringa (Leiden University, Leiden, The Netherlands), Ben Scheres (University of Utrecht, Utrecht, The Netherlands), Chris Somerville (University of California, Berkeley, CA, USA), Sacco de Vries (Wageningen University, Wageningen, The Netherlands) and Dolf Weijers (Wageningen University, Wageningen, The Netherlands) for sharing published materials and Martine De Cock for help in preparing the manuscript.
Open access: yes (repository)