The Na+/I- symporter (NIS): recent advances.

The Na+/I- symporter (NIS) catalyzes the accumulation of iodide into thyroid cells, an essential step in the biosynthesis of thyroid hormones. As a result of the isolation of the rat NIS cDNA, steadfast advances in the study of NIS at the molecular level have resulted in the following accomplishments: generation of high-affinity anti-NIS antibodies, elucidation of NIS stoichiometry and specificity by electrophysiological analysis, biochemical and immunological experimental testing of the proposed NIS secondary structure model, monitoring the regulation of NIS protein expression by thyroid stimulating hormone and iodide, characterization of the rat NIS gene promoter, isolation of the cDNA clone encoding human NIS and subsequent determination of human NIS genomic organization, description of NIS mutations in patients with congenital lack of iodide transport, and the molecular identification of NIS in extrathyroidal tissues.