Pendrin, the protein encoded by the Pendred syndrome gene (PDS), is an apical porter of iodide in the thyroid and is regulated by thyroglobulin in FRTL-5 cells.
Pendred syndrome is an autosomal recessive disorder characterized by congenital deafness and thyroid goiter. The thyroid disease typically develops around puberty and is associated with a mild organification defect, characterized by an inappropriate discharge of iodide upon perchlorate stimulation (a positive perchlorate discharge test). The gene (PDS) mutated in Pendred syndrome is expressed in thyroid and encodes a 780-amino acid protein (pendrin) that has recently been shown to function as an iodide/chloride transporter. We sought to establish the location of pendrin in the thyroid and to examine the regulatory network controlling its synthesis. Using peptide-specific antibodies for immunolocalization studies, pendrin was detected in a limited subset of cells within the thyroid follicles, exclusively at the apical membrane of the follicular epithelium. Interestingly, significantly greater amounts of pendrin were encountered in thyroid tissue from patients with Graves' disease. Using a cultured rat thyroid cell line (FRTL-5), PDS expression was found to be significantly induced by low concentrations of thyroglobulin (TG), but not by TSH, sodium iodide, or insulin. This is different from the established effect of TG, more typically a potent suppressor of thyroid-specific gene expression. Together, these results suggest that pendrin is an apical porter of iodide in the thyroid and that the expression and function of both the apical and basal iodide porters are coordinately regulated by follicular TG.
Royaux
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IE
Genome Technology Branch, National Human Genome Research Institute, National Institute of Health, Bethesda, Maryland 20892, USA.
Suzuki
K
K
Mori
A
A
Katoh
R
R
Everett
L A
LA
Kohn
L D
LD
Green
E D
ED
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007454:Iodides / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis; D012974:Sodium Iodide / Q000494:pharmacology; D000076988:Sulfate Transporters; D013954:Thyroglobulin / Q000494:pharmacology*; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology; D014158:Transcription, Genetic; D014162:Transfection
D000906:Antibodies; D002352:Carrier Proteins; D007328:Insulin; D007454:Iodides; D026901:Membrane Transport Proteins; D010446:Peptide Fragments; D012333:RNA, Messenger; D011994:Recombinant Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D013972:Thyrotropin; D013954:Thyroglobulin; D012974:Sodium Iodide