title: The tonoplast copper transporter COPT5 acts as an exporter and is required for interorgan allocation of copper in Arabidopsis thaliana.
abstract: Copper is an essential micronutrient for all organisms because it serves as a cofactor of several proteins involved in electron transfer. Elevated copper concentrations can cause toxic effects and organisms have established suitable mechanisms to regulate the uptake and internal distribution of copper to balance the content at an optimal concentration. In recent studies, a family of copper transporters (COPT) with high homology to other eukaryotic copper transporters (Ctr) has been identified in Arabidopsis thaliana. In this study we clarified the physiological function of COPT5. This carrier is located in the tonoplast and functions as a vacuolar copper exporter. Mutants lacking this transporter have altered copper contents in different organs when compared with wild-type plants. We were able to detect copper accumulation in the root and a decreased copper content in siliques and seeds when the COPT5 gene is mutated by T-DNA insertion. Vacuoles purified from copt5 T-DNA-insertion mutants show remarkably increased copper concentrations compared with wild-type organelles. We assume that on the cellular level COPT5 is important for copper export from the vacuole and on the level of the whole plant it is involved in the interorgan reallocation of copper ions from the root to reproductive organs.
authors.affiliation: Technische Universität Kaiserslautern, Pflanzenphysiologie, Postfach 3049, Kaiserslautern, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Klaumann
authors.forename: Sebastian D
authors.initials: SD
authors.lastname: Nickolaus
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Fürst
authors.forename: Sabrina
authors.initials: S
authors.lastname: Starck
authors.forename: Sabine
authors.initials: S
authors.lastname: Schneider
authors.forename: H
authors.initials: H
authors.lastname: Ekkehard Neuhaus
authors.forename: Oliver
authors.initials: O
authors.lastname: Trentmann
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D004579:Electron Transport; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D014644:Genetic Variation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006706:Homeostasis; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D000080083:SLC31 Proteins; D014617:Vacuoles / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C559588:COPT5 protein, Arabidopsis; D027682:Cation Transport Proteins; D000080083:SLC31 Proteins; D049452:Green Fluorescent Proteins; D003300:Copper