title: The copper transporter RAN1 is essential for biogenesis of ethylene receptors in Arabidopsis.
abstract: Plants utilize ethylene as a hormone to regulate multiple developmental processes and to coordinate responses to biotic and abiotic stress. In Arabidopsis thaliana, a small family of five receptor proteins typified by ETR1 mediates ethylene perception. Our previous work suggested that copper ions likely play a role in ethylene binding. An independent study indicated that the ran1 mutants, which display ethylene-like responses to the ethylene antagonist trans-cyclooctene, have mutations in the RAN1 copper-transporting P-type ATPase, once again linking copper ions to the ethylene-response pathway. The results presented herein indicate that genetically engineered Saccharomyces cerevisiae expressing ETR1 but lacking the RAN1 homolog Ccc2p (Δccc2) lacks ethylene-binding activity. Ethylene-binding activity was restored when copper ions were added to the Δccc2 mutants, showing that it is the delivery of copper that is important. Additionally, transformation of the Δccc2 mutant yeast with RAN1 rescued ethylene-binding activity. Analysis of plants carrying loss-of-function mutations in ran1 showed that they lacked ethylene-binding activity, whereas seedlings carrying weak alleles of ran1 had normal ethylene-binding activity but were hypersensitive to copper-chelating agents. Altogether, the results show an essential role for RAN1 in the biogenesis of the ethylene receptors and copper homeostasis in Arabidopsis seedlings. Furthermore, the results indicate cross-talk between the ethylene-response pathway and copper homeostasis in Arabidopsis seedling development.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Brad M
authors.initials: BM
authors.lastname: Binder
authors.forename: Fernando I
authors.initials: FI
authors.lastname: Rodríguez
authors.forename: Anthony B
authors.initials: AB
authors.lastname: Bleecker
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D000079922:Copper Transport Proteins; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D011485:Protein Binding; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D020931:ran GTP-Binding Protein
chemical_list: D029681:Arabidopsis Proteins; C490178:At5g20010 protein, Arabidopsis; C092974:CCC2 protein, S cerevisiae; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; C494590:ETR1 protein, Arabidopsis; D005030:Ethylenes; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; D003300:Copper; C036216:ethylene; D020931:ran GTP-Binding Protein