Mechanism of iodide/chloride exchange by pendrin.
Endocrinology
; 145(9): 4301-8, 2004 Sep.
Article
em En
| MEDLINE
| ID: mdl-15155570
ABSTRACT
We performed an electrophysiological study to investigate ion transport of pendrin and thereby understand the pathogenesis of Pendred syndrome. Using pendrin-transfected COS-7 cells, we could show that pendrin transports both iodide and chloride measured as voltage-dependent inward and outward membrane currents. Chloride in the culture medium, [Cl-]o, was efficiently exchanged with cytoplasmic iodide, [I-]i, under physiological concentrations, indicating that pendrin is important for chloride uptake and iodide efflux. Although exchange of iodide in the medium, [I-]o, with cytoplasmic chloride, [Cl-]i, was observed, a significantly high concentration of iodide (10 mm) was required. In addition, either iodide or chloride was required on both sides of the cell membrane for the anion exchange activity of pendrin, indicating that iodide and chloride activate the exchange activity of pendrin while they are transported. The present study further supports that pendrin is responsible for the iodide efflux in thyroid cells where intracellular iodide concentration is high and that the general function of pendrin in other tissues is to transport chloride through exchange with other anions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Membrana Transportadoras
/
Proteínas de Transporte
/
Cloretos
/
Iodetos
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Endocrinology
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Japão