TWISTED DWARF1 Mediates the Action of Auxin Transport Inhibitors on Actin Cytoskeleton Dynamics

Jinsheng Zhu, Aurelien Bailly, Marta Zwiewka, Valpuri Sovero, Martin Di Donato, Pei Ge, Jacqueline Oehri, Bibek Aryal, Pengchao Hao, Miriam Linnert, Noelia Inés Burgardt, Christian Lücke, Matthias Weiwad, Max Michel, Oliver H. Weiergräber, Stephan Pollmann, Elisa Azzarello, Stefano Mancuso, Noel Ferro, Yoichiro FukaoCéline Hoffmann, Roland Wedlich-Söldner, Jiří Friml, Clément Thomas, Markus Geisler*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

70 Citations (Scopus)


Plant growth and architecture is regulated by the polar distribution of the hormone auxin. Polarity and flexibility of this process is provided by constant cycling of auxin transporter vesicles along actin filaments, coordinated by a positive auxinactin feedback loop. Both polar auxin transport and vesicle cycling are inhibited by synthetic auxin transport inhibitors, such as 1-Nnaphthylphthalamic acid (NPA), counteracting the effect of auxin; however, underlying targets and mechanisms are unclear. Using NMR, we map the NPA binding surface on the Arabidopsis thaliana ABCB chaperone TWISTED DWARF1 (TWD1).We identify ACTIN7 as a relevant, although likely indirect, TWD1 interactor, and show TWD1-dependent regulation of actin filament organization and dynamics and that TWD1 is required for NPA-mediated actin cytoskeleton remodeling. The TWD1-ACTIN7 axis controls plasma membrane presence of efflux transporters, and as a consequence act7 and twd1 share developmental and physiological phenotypes indicative of defects in auxin transport. These can be phenocopied by NPA treatment or by chemical actin (de)stabilization. We provide evidence that TWD1 determines downstreamlocations of auxin efflux transporters by adjusting actin filament debundling and dynamizing processes and mediating NPA action on the latter. This function appears to be evolutionary conserved since TWD1 expression in budding yeast alters actin polarization and cell polarity and provides NPA sensitivity.

Original languageEnglish
Pages (from-to)930-948
Number of pages19
JournalPlant Cell
Issue number4
Publication statusPublished - Apr 2016


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