title: The intracellular Arabidopsis COPT5 transport protein is required for photosynthetic electron transport under severe copper deficiency.
abstract: Copper is an essential micronutrient that functions as a redox cofactor in multiple plant processes, including photosynthesis. Arabidopsis thaliana possesses a conserved family of CTR-like high-affinity copper transport proteins denoted as COPT1-5. COPT1, the only family member that is functionally characterized, participates in plant copper acquisition. However, little is known about the function of the other Arabidopsis COPT proteins in the transport and distribution of copper. Here, we show that a functional fusion of COPT5 to the green fluorescent protein localizes in Arabidopsis cells to the prevacuolar compartment. Plants defective in COPT5 do not exhibit any significant phenotype under copper-sufficient conditions, but their growth is compromised under copper limitation. Under extreme copper deficiency, two independent copt5 knockout mutant lines exhibit severe defects in vegetative growth and root elongation, low chlorophyll content, and impairment in the photosynthetic electron transfer. All these phenotypes are rescued when the wild-type copy of the COPT5 gene is retransformed into a copt5 knockout line or when copper, but not other metals, are added to the medium. COPT5 is expressed in vascular tissues, with elevated levels in roots. Taken together, these results suggest that COPT5 plays an important role in the plant response to environmental copper scarcity, probably by remobilizing copper from prevacuolar vesicles, which could act as internal stores or recycling vesicles to provide the metal cofactor to key copper-dependent processes such as photosynthesis.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, Ave. Doctor Moliner 50, E-46100 Burjassot, València, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Garcia-Molina
authors.forename: Nuria
authors.initials: N
authors.lastname: Andrés-Colás
authors.forename: Ana
authors.initials: A
authors.lastname: Perea-García
authors.forename: Secundino
authors.initials: S
authors.lastname: Del Valle-Tascón
authors.forename: Lola
authors.initials: L
authors.lastname: Peñarrubia
authors.forename: Sergi
authors.initials: S
authors.lastname: Puig
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000172:deficiency / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D004579:Electron Transport; D055786:Gene Knockout Techniques; D017343:Genes, Plant; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000080083:SLC31 Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C559588:COPT5 protein, Arabidopsis; D027682:Cation Transport Proteins; D018744:DNA, Plant; D011993:Recombinant Fusion Proteins; D000080083:SLC31 Proteins; D049452:Green Fluorescent Proteins; D003300:Copper