Unknown

Dataset Information

0

The iodide-transport-defect-causing mutation R124H: a ?-amino group at position 124 is critical for maturation and trafficking of the Na+/I- symporter.


ABSTRACT: Na(+)/I(-) symporter (NIS)-mediated active accumulation of I(-) in thyrocytes is a key step in the biosynthesis of the iodine-containing thyroid hormones T3 and T4. Several NIS mutants have been identified as a cause of congenital I(-) transport defect (ITD), and their investigation has yielded valuable mechanistic information on NIS. Here we report novel findings derived from the thorough characterization of the ITD-causing mutation R124H, located in the second intracellular loop (IL-2). R124H NIS is incompletely glycosylated and colocalizes with endoplasmic reticulum (ER)-resident protein markers. As a result, R124H NIS is not targeted to the plasma membrane and therefore does not mediate any I(-) transport in transfected COS-7 cells. Strikingly, however, the mutant is intrinsically active, as revealed by its ability to mediate I(-) transport in membrane vesicles. Of all the amino acid substitutions we carried out at position 124 (K, D, E, A, W, N and Q), only Gln restored targeting of NIS to the plasma membrane and NIS activity, suggesting a key structural role for the ?-amino group of R124 in the transporter's maturation and cell surface targeting. Using our NIS homology model based on the structure of the Vibrio parahaemolyticus Na(+)/galactose symporter, we propose an interaction between the ?-amino group of either R or Q124 and the thiol group of C440, located in IL-6. We conclude that the interaction between IL-2 and IL-6 is critical for the local folding required for NIS maturation and plasma membrane trafficking.

SUBMITTER: Paroder V 

PROVIDER: S-EPMC3730242 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

altmetric image

Publications

The iodide-transport-defect-causing mutation R124H: a δ-amino group at position 124 is critical for maturation and trafficking of the Na+/I- symporter.

Paroder Viktoriya V   Nicola Juan P JP   Ginter Christopher S CS   Carrasco Nancy N  

Journal of cell science 20130520 Pt 15


Na(+)/I(-) symporter (NIS)-mediated active accumulation of I(-) in thyrocytes is a key step in the biosynthesis of the iodine-containing thyroid hormones T3 and T4. Several NIS mutants have been identified as a cause of congenital I(-) transport defect (ITD), and their investigation has yielded valuable mechanistic information on NIS. Here we report novel findings derived from the thorough characterization of the ITD-causing mutation R124H, located in the second intracellular loop (IL-2). R124H  ...[more]

Similar Datasets

| S-EPMC8377515 | biostudies-literature
| S-EPMC2670652 | biostudies-literature
| S-EPMC4248369 | biostudies-literature
| S-EPMC8861941 | biostudies-literature
| S-EPMC3002920 | biostudies-literature
| S-EPMC6797079 | biostudies-literature
| S-EPMC2154417 | biostudies-literature
| S-EPMC2852426 | biostudies-literature
| S-EPMC7679261 | biostudies-literature
| S-EPMC5509730 | biostudies-literature