title: Arabidopsis TWISTED DWARF1 functionally interacts with auxin exporter ABCB1 on the root plasma membrane.
abstract: Plant architecture is influenced by the polar, cell-to-cell transport of auxin that is primarily provided and regulated by plasma membrane efflux catalysts of the PIN-FORMED and B family of ABC transporter (ABCB) classes. The latter were shown to require the functionality of the FK506 binding protein42 TWISTED DWARF1 (TWD1), although underlying mechanisms are unclear. By genetic manipulation of TWD1 expression, we show here that TWD1 affects shootward root auxin reflux and, thus, downstream developmental traits, such as epidermal twisting and gravitropism of the root. Using immunological assays, we demonstrate a predominant lateral, mainly outward-facing, plasma membrane location for TWD1 in the root epidermis characterized by the lateral marker ABC transporter G36/PLEIOTROPIC DRUG-RESISTANCE8/PENETRATION3. At these epidermal plasma membrane domains, TWD1 colocalizes with nonpolar ABCB1. In planta bioluminescence resonance energy transfer analysis was used to verify specific ABC transporter B1 (ABCB1)-TWD1 interaction. Our data support a model in which TWD1 promotes lateral ABCB-mediated auxin efflux via protein-protein interaction at the plasma membrane, minimizing reflux from the root apoplast into the cytoplasm.
authors: Department of Biology-Plant Biology, University of Fribourg, 1700 Fribourg, Switzerland.
authors: Bangjun
authors: B
authors: Wang
authors: Aurélien
authors: A
authors: Bailly
authors: Marta
authors: M
authors: Zwiewka
authors: Sina
authors: S
authors: Henrichs
authors: Elisa
authors: E
authors: Azzarello
authors: Stefano
authors: S
authors: Mancuso
authors: Masayoshi
authors: M
authors: Maeshima
authors: Jirí
authors: J
authors: Friml
authors: Alexander
authors: A
authors: Schulz
authors: Markus
authors: M
authors: Geisler
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018522:Gravitropism; D007210:Indoleacetic Acids / Q000032:analysis / Q000378:metabolism*; D018613:Microscopy, Confocal; D009154:Mutation; D010641:Phenotype; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins; D022021:Tacrolimus Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; C114215:ATPGP1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D011993:Recombinant Fusion Proteins; C471286:TWD1 protein, Arabidopsis; D022021:Tacrolimus Binding Proteins