A Carboxy-Terminal Monoleucine-Based Motif Participates in the Basolateral Targeting of the Na+/I− Symporter

MASINI-REPISO, ANA MARÍA

Endocrinology

Endocrine Society

Año: 2019 vol. 160 p. 156 - 156

he Na+/iodide (I2) symporter (NIS), a glycoprotein expressed at the basolateral plasma membrane of thyroid follicular cells, mediates I2 accumulation for thyroid hormonogenesis and radioiodide therapy for differentiated thyroid carcinoma. However, differentiated thyroid tumors often exhibit lower I2 transport than normal thyroid tissue (or even undetectable I2 transport). Paradoxically, the majority of differentiated thyroid cancers show intracellular NIS expression, suggesting abnormal targeting to the plasma membrane. Therefore, a thorough understanding of the mechanisms that regulate NIS plasma membrane transport would have multiple implications for radioiodide therapy.In this study, we show that the intracellularly facing carboxy-terminus of NIS is required for the transport of the protein to the plasma membrane. Moreover, the carboxy-terminus contains dominant basolateral information. Using internal deletions and site-directed mutagenesis at the carboxy-terminus, we identified a