title: Functional redundancy of PIN proteins is accompanied by auxin-dependent cross-regulation of PIN expression.
abstract: Plant development displays an exceptional plasticity and adaptability that involves the dynamic, asymmetric distribution of the phytohormone auxin. Polar auxin flow, which requires polarly localized transport facilitators of the PIN family, largely contributes to the establishment and maintenance of the auxin gradients. Functionally overlapping action of PIN proteins mediates multiple developmental processes, including embryo formation, organ development and tropisms. Here we show that PIN proteins exhibit synergistic interactions, which involve cross-regulation of PIN gene expression in pin mutants or plants with inhibited auxin transport. Auxin itself positively feeds back on PIN gene expression in a tissue-specific manner through an AUX/IAA-dependent signalling pathway. This regulatory switch is indicative of a mechanism by which the loss of a specific PIN protein is compensated for by auxin-dependent ectopic expression of its homologues. The compensatory properties of the PIN-dependent transport network might enable the stabilization of auxin gradients and potentially contribute to the robustness of plant adaptive development.
authors.affiliation: Centre for Molecular Biology of Plants, University Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Vieten
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.forename: Justyna
authors.initials: J
authors.lastname: Wisniewska
authors.forename: Eva
authors.initials: E
authors.lastname: Benková
authors.forename: René
authors.initials: R
authors.lastname: Benjamins
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Christian
authors.initials: C
authors.lastname: Luschnig
authors.forename: Jirí
authors.initials: J
authors.lastname: Friml
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis