title: Prototype cell-to-cell auxin transport mechanism by intracellular auxin compartmentalization.
abstract: Carrier-dependent, intercellular auxin transport is central to the developmental patterning of higher plants (tracheophytes). The evolution of this polar auxin transport might be linked to the translocation of some PIN auxin efflux carriers from their presumably ancestral localization at the endoplasmic reticulum (ER) to the polar domains at the plasma membrane. Here we propose an eventually ancient mechanism of intercellular auxin distribution by ER-localized auxin transporters involving intracellular auxin retention and switch-like release from the ER. The proposed model integrates feedback circuits utilizing the conserved nuclear auxin signaling for the regulation of PIN transcription and a hypothetical ER-based signaling for the regulation of PIN-dependent transport activity at the ER. Computer simulations of the model revealed its plausibility for generating auxin channels and localized auxin maxima highlighting the possibility of this alternative mechanism for polar auxin transport.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Gent, Belgium.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Wabnik
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kleine-Vehn
authors.forename: Willy
authors.initials: W
authors.lastname: Govaerts
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D003593:Cytoplasm / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D059828:Plant Cells / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083846:auxin-binding protein 1