Auxin transport inhibitors impair vesicle motility and actin cytoskeleton dynamics in diverse eukaryotes Journal Article

Author(s): Dhonukshe, Pankaj; Grigoriev, Ilya S; Fischer, Rainer; Tominaga, Motoki; Robinson, David G; Hašek, Jiří; Paciorek, Tomasz; Petrášek, Jan; Seifertová, Daniela; Tejos, Ricardo; Meisel, Lee A; Zažímalová, Eva; Gadella, Theodorus W; Stierhof, York-Dieter; Ueda, Takashi; Oiwa, Kazuhiro; Akhmanova, Anna; Brock, Roland; Spang, Anne; Friml, Jiří
Article Title: Auxin transport inhibitors impair vesicle motility and actin cytoskeleton dynamics in diverse eukaryotes
Abstract: Many aspects of plant development, including patterning and tropisms, are largely dependent on the asymmetric distribution of the plant signaling molecule auxin. Auxin transport inhibitors (ATIs), which interfere with directional auxin transport, have been essential tools in formulating this concept. However, despite the use of ATIs in plant research for many decades, the mechanism of ATI action has remained largely elusive. Using real-time live-cell microscopy, we show here that prominent ATIs such as 2,3,5-triiodobenzoic acid (TIBA) and 2-(1-pyrenoyl) benzoic acid (PBA) inhibit vesicle trafficking in plant, yeast, and mammalian cells. Effects on micropinocytosis, rab5-labeled endosomal motility at the periphery of HeLa cells and on fibroblast mobility indicate that ATIs influence actin cytoskeleton. Visualization of actin cytoskeleton dynamics in plants, yeast, and mammalian cells show that ATIs stabilize actin. Conversely, stabilizing actin by chemical or genetic means interferes with endocytosis, vesicle motility, auxin transport, and plant development, including auxin transport-dependent processes. Our results show that a class of ATIs act as actin stabilizers and advocate that actin-dependent trafficking of auxin transport components participates in the mechanism of auxin transport. These studies also provide an example of how the common eukaryotic process of actin-based vesicle motility can fulfill a plant-specific physiological role.
Keywords: Plant development; Vesicle traffic; Auxin efflux inhibitors; PIN proteins
Journal Title: PNAS
Volume: 105
Issue 11
ISSN: 1091-6490
Publisher: National Academy of Sciences  
Date Published: 2008-03-18
Start Page: 4489
End Page: 4494
DOI: 10.1073/pnas.0711414105
Open access: no