Search Results
You are looking at 1 - 1 of 1 items for
- Author: Sylvaine Huc x
- Refine by access: Content accessible to me x
Search for other papers by Manal Dayem in
Google Scholar
PubMed
Search for other papers by Cécile Basquin in
Google Scholar
PubMed
Search for other papers by Valérie Navarro in
Google Scholar
PubMed
Search for other papers by Patricia Carrier in
Google Scholar
PubMed
Search for other papers by Robert Marsault in
Google Scholar
PubMed
Search for other papers by Patrick Chang in
Google Scholar
PubMed
Search for other papers by Sylvaine Huc in
Google Scholar
PubMed
Search for other papers by Elisabeth Darrouzet in
Google Scholar
PubMed
Search for other papers by Sabine Lindenthal in
Google Scholar
PubMed
Search for other papers by Thierry Pourcher in
Google Scholar
PubMed
The active transport of iodide from the bloodstream into thyroid follicular cells is mediated by the Na+/I− symporter (NIS). We studied mouse NIS (mNIS) and found that it catalyzes iodide transport into transfected cells more efficiently than human NIS (hNIS). To further characterize this difference, we compared 125I uptake in the transiently transfected human embryonic kidney (HEK) 293 cells. We found that the V max for mNIS was four times higher than that for hNIS, and that the iodide transport constant (K m) was 2.5-fold lower for hNIS than mNIS. We also performed immunocytolocalization studies and observed that the subcellular distribution of the two orthologs differed. While the mouse protein was predominantly found at the plasma membrane, its human ortholog was intracellular in ∼40% of the expressing cells. Using cell surface protein-labeling assays, we found that the plasma membrane localization frequency of the mouse protein was only 2.5-fold higher than that of the human protein, and therefore cannot alone account for the difference in the obtained V max values. We reasoned that the observed difference could also be caused by a higher turnover number for iodide transport in the mouse protein. We then expressed and analyzed chimeric proteins. The data obtained with these constructs suggest that the iodide recognition site could be located in the region extending from the N-terminus to transmembrane domain 8, and that the region between transmembrane domain 5 and the C-terminus could play a role in the subcellular localization of the protein.