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Copper uptake mechanism of Arabidopsis thaliana high-affinity COPT transporters.
Sanz, Amparo; Pike, Sharon; Khan, Mather A; Carrió-Seguí, Àngela; Mendoza-Cózatl, David G; Peñarrubia, Lola; Gassmann, Walter.
Afiliação
  • Sanz A; Dpt de Biologia Vegetal, Universitat de València, c/ Dr Moliner 50, 46100-Burjassot, Valencia, Spain. Amparo.Sanz@uv.es.
  • Pike S; Division of Plant Sciences, CS Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, 1201 Rollins St, Columbia, MO, 65211, USA.
  • Khan MA; Division of Plant Sciences, CS Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, 1201 Rollins St, Columbia, MO, 65211, USA.
  • Carrió-Seguí À; Dpt de Bioquímica i Biologia Molecular and ERI Biotecmed, Universitat de València, c/ Dr Moliner 50, 46100-Burjassot, Valencia, Spain.
  • Mendoza-Cózatl DG; Division of Plant Sciences, CS Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, 1201 Rollins St, Columbia, MO, 65211, USA.
  • Peñarrubia L; Dpt de Bioquímica i Biologia Molecular and ERI Biotecmed, Universitat de València, c/ Dr Moliner 50, 46100-Burjassot, Valencia, Spain.
  • Gassmann W; Division of Plant Sciences, CS Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, 1201 Rollins St, Columbia, MO, 65211, USA.
Protoplasma ; 256(1): 161-170, 2019 Jan.
Article em En | MEDLINE | ID: mdl-30043153
ABSTRACT
Copper (Cu) is an essential plant micronutrient. Under scarcity, Cu2+ is reduced to Cu+ and taken up through specific high-affinity transporters (COPTs). In Arabidopsis, the COPT family consists of six members, either located at the plasma membrane (COPT1, COPT2, and COPT6) or in internal membranes (COPT3 and COPT5). Cu uptake by COPT proteins has been mainly assessed through complementation studies in corresponding yeast mutants, but the mechanism of this transport has not been elucidated. To test whether Cu is incorporated by an electrogenic mechanism, electrophysiological changes induced by Cu addition were studied in Arabidopsis thaliana. Mutant (T-DNA insertion mutants, copt2-1 and copt5-2) and overexpressing lines (COPT1OE and COPT5OE) with altered expression of COPT transporters were compared to wild-type plants. No significant changes of the membrane potential (Em) were detected, regardless of genotype or Cu concentration supplied. In contrast, membrane depolarization was detected in response to iron supply in both wild-type and in mutant or transgenic plants. Similar results were obtained for trans-plant potentials (TPP). GFP fusions of the plasma membrane COPT2 and the internal COPT5 transporters were expressed in Xenopus laevis oocytes to potentiate Cu uptake signals, and the cRNA-injected oocytes were tested for electrical currents upon Cu addition using two-electrode voltage clamp. Results with oocytes confirmed those obtained in plants. Cu accumulation in injected oocytes was measured by ICP-OES, and a significant increase in Cu content with respect to controls occurred in oocytes expressing COPT2GFP. The possible mechanisms driving this transport are discussed in this manuscript.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Arabidopsis / Cobre / Proteínas de Transporte de Cátions Idioma: En Revista: Protoplasma Assunto da revista: BIOLOGIA Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Espanha

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Arabidopsis / Cobre / Proteínas de Transporte de Cátions Idioma: En Revista: Protoplasma Assunto da revista: BIOLOGIA Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Espanha