title: Trafficking modulator TENin1 inhibits endocytosis, causes endomembrane protein accumulation at the pre-vacuolar compartment and impairs gravitropic response in Arabidopsis thaliana.
abstract: Auxin gradients are established and maintained by polarized distribution of auxin transporters that undergo constitutive endocytic recycling from the PM (plasma membrane) and are essential for the gravitropic response in plants. The present study characterizes an inhibitor of endomembrane protein trafficking, TE1 (trafficking and endocytosis inhibitor 1/TENin1) that reduces gravitropic root bending in Arabidopsis thaliana seedlings. Short-term TE1 treatment causes accumulation of PM proteins, including the BR (brassinosteroid) receptor BRI1 (BR insensitive 1), PIP2a (PM intrinsic protein 2a) and the auxin transporter PIN2 (PIN-FORMED 2) in a PVC (pre-vacuolar related compartment), which is sensitive to BFA (Brefeldin A). This compound inhibits endocytosis from the PM and promotes trafficking to the vacuole, consistent with inhibition of retrieval of proteins to the TGN (trans-Golgi network) from the PVC and the PM. However, trafficking of newly synthesized proteins to the PM is unaffected. The short-term protein trafficking inhibition and long-term effect on plant growth and survival caused by TE1 were fully reversible upon drug washout. Structure-activity relationship studies revealed that only minor modifications were possible without loss of biological activity. Diversity in Arabidopsis ecotypes was also exploited to identify two Arabidopsis accessions that display reduced sensitivity to TE1. This compound and the resistant Arabidopsis accessions may be used as a resource in future studies to better understand endomembrane trafficking in plants.
authors.affiliation: *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Rupesh
authors.initials: R
authors.lastname: Paudyal
authors.affiliation: *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Adam
authors.initials: A
authors.lastname: Jamaluddin
authors.affiliation: †School of Chemistry, Faculty of Mathematics and Physical Sciences, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: James P
authors.initials: JP
authors.lastname: Warren
authors.affiliation: ‡Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå 90183, Sweden.
authors.forename: Siamsa M
authors.initials: SM
authors.lastname: Doyle
authors.affiliation: ‡Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå 90183, Sweden.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Robert
authors.affiliation: †School of Chemistry, Faculty of Mathematics and Physical Sciences, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Warriner
authors.affiliation: *Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Alison
authors.initials: A
authors.lastname: Baker
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects*; D018522:Gravitropism / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects*; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects; D014617:Vacuoles / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; C092350:FM 4-64; C117013:AT5G57090 protein, Arabidopsis