title: Effects of Auxins on PIN-FORMED2 (PIN2) Dynamics Are Not Mediated by Inhibiting PIN2 Endocytosis.
abstract: By using the photoconvertible fluorescence protein Dendra2 as a tag we demonstrated that neither the naturally occurring auxins indole-3-acetic acid and indole-3-butyric acid, nor the synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid nor compounds inhibiting polar auxin transport such as 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid, were able to inhibit endocytosis of the putative auxin transporter PIN-FORMED2 (PIN2) in Arabidopsis (Arabidopsis thaliana) root epidermis cells. All compounds, except Indole-3-butyric acid, repressed the recovery of the PIN2-Dendra2 plasma membrane pool after photoconversion when they were used in high concentrations. The synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid showed the strongest inhibition. Auxins and auxin transport inhibitors suppressed also the accumulation of both newly synthesized and endocytotic PIN2 pools in Brefeldin A compartments (BFACs). Furthermore, we demonstrated that all compounds are also interfering with BFAC formation. The synthetic auxin analogs caused the highest reduction in the number and size of BFACs. We concluded that auxins and inhibitors of auxin transport do affect PIN2 turnover in the cells, but it is through the synthetic rather than the endocytotic pathway. The study also confirmed inappropriateness of the BFA-based approach to study PIN2 endocytosis because the majority of PIN2 accumulating in BFACs is newly synthesized and not derived from the plasma membrane.
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.) jan.jasik@rec.uniba.sk.
authors: Ján
authors: J
authors: Jásik
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.).
authors: Boris
authors: B
authors: Bokor
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.).
authors: Stanislav
authors: S
authors: Stuchlík
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.).
authors: Karol
authors: K
authors: Mičieta
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.).
authors: Ján
authors: J
authors: Turňa
authors: Comenius University Science Park, Comenius University, 841 04 Bratislava, Slovakia (J.J., B.B., S.S., K.M., J.T.); Institute of Botany, Slovak Academy of Sciences, 845 23 Bratislava (J.J.); Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava, Slovakia (S.S., J.T.); Department of Botany, Faculty of Natural Sciences, Comenius University, 811 02 Bratislava, Slovakia (K.M.); and Central Microscopy, Max Planck Institute for Plant Breeding Research, 508 29 Cologne, Germany (E.S.).
authors: Elmon
authors: E
authors: Schmelzer
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D059008:Time-Lapse Imaging / Q000379:methods
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D007211:Indoles; D008164:Luminescent Proteins; D010937:Plant Growth Regulators; C583169:Dendra2 protein, Dendronephthya; C117013:AT5G57090 protein, Arabidopsis; C014612:indolebutyric acid