Pendrin does not increase sulfate uptake in mammalian COS-7 cells.
Pendred's syndrome is characterized by goiter, sensorineural deafness and impaired iodide organification. It is one of the most frequent causes of congenital deafness accounting for about 10% of hereditary hearing loss. It is caused by mutations in the pendrin (PDS) gene, which was postulated to be a sulfate transporter, because of its homology with other genes. We tested sulfate transport in mammalian COS-7 cells that were transiently transfected with PDS cDNA. 35SO4 uptake increased in a time-dependent manner, but this phenomenon was similar in cells transfected with PDS and in mock-transfected cells (450 and 360 cpm/beta-gal units at 10 min, respectively; 38,250 and 31,000 cpm/beta-gal units, at 12 h, respectively). There was no significant increase in 35SO4 uptake using increasing amounts of PDS-containing plasmid (up to 12 microg per dish). These data indicate that pendrin is not a sulfate transporter. Additional functional studies on this protein are warranted to clarify its role in thyroid pathophysiology and inner ear development.
Bogazzi
F
F
Dipartimento di Endocrinologia e Metabolismo, Ortopedia e Traumatologia, Medicina del Lavoro, University of Pisa, Italy. fbogazzi@hotmail.com
Bartalena
L
L
Raggi
F
F
Ultimieri
F
F
Martino
E
E
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D019556:COS Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D018076:DNA, Complementary / Q000096:biosynthesis; D026901:Membrane Transport Proteins; D010957:Plasmids / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000076988:Sulfate Transporters; D013431:Sulfates / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D014162:Transfection / Q000235:genetics
D002352:Carrier Proteins; D018076:DNA, Complementary; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D013431:Sulfates; D013462:Sulfur Radioisotopes