Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport
The epithelial anion transporter SLC26A9 contributes to airway surface hydration and gastric acid production. Colocalizing with CFTR, SLC26A9 has been proposed as a target for the treatment of cystic fibrosis. To provide molecular details of its transport mechanism, we present cryo-EM structures and...
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eLife Sciences Publications Ltd
2019-07-01
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Online Access: | https://elifesciences.org/articles/46986 |
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author | Justin D Walter Marta Sawicka Raimund Dutzler |
author_facet | Justin D Walter Marta Sawicka Raimund Dutzler |
author_sort | Justin D Walter |
collection | DOAJ |
description | The epithelial anion transporter SLC26A9 contributes to airway surface hydration and gastric acid production. Colocalizing with CFTR, SLC26A9 has been proposed as a target for the treatment of cystic fibrosis. To provide molecular details of its transport mechanism, we present cryo-EM structures and a functional characterization of murine Slc26a9. These structures define the general architecture of eukaryotic SLC26 family members and reveal an unusual mode of oligomerization which relies predominantly on the cytosolic STAS domain. Our data illustrates conformational transitions of Slc26a9, supporting a rapid alternate-access mechanism which mediates uncoupled chloride transport with negligible bicarbonate or sulfate permeability. The characterization of structure-guided mutants illuminates the properties of the ion transport path, including a selective anion binding site located in the center of a mobile module within the transmembrane domain. This study thus provides a structural foundation for the understanding of the entire SLC26 family and potentially facilitates their therapeutic exploitation. |
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institution | Directory Open Access Journal |
issn | 2050-084X |
language | English |
last_indexed | 2024-04-14T07:57:58Z |
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spelling | doaj.art-dbe2fb604f9d45c8a7fe11a823aff74f2022-12-22T02:04:58ZengeLife Sciences Publications LtdeLife2050-084X2019-07-01810.7554/eLife.46986Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transportJustin D Walter0https://orcid.org/0000-0002-1492-3055Marta Sawicka1https://orcid.org/0000-0003-4589-4290Raimund Dutzler2https://orcid.org/0000-0002-2193-6129Department of Biochemistry, University of Zurich, Zurich, SwitzerlandDepartment of Biochemistry, University of Zurich, Zurich, SwitzerlandDepartment of Biochemistry, University of Zurich, Zurich, SwitzerlandThe epithelial anion transporter SLC26A9 contributes to airway surface hydration and gastric acid production. Colocalizing with CFTR, SLC26A9 has been proposed as a target for the treatment of cystic fibrosis. To provide molecular details of its transport mechanism, we present cryo-EM structures and a functional characterization of murine Slc26a9. These structures define the general architecture of eukaryotic SLC26 family members and reveal an unusual mode of oligomerization which relies predominantly on the cytosolic STAS domain. Our data illustrates conformational transitions of Slc26a9, supporting a rapid alternate-access mechanism which mediates uncoupled chloride transport with negligible bicarbonate or sulfate permeability. The characterization of structure-guided mutants illuminates the properties of the ion transport path, including a selective anion binding site located in the center of a mobile module within the transmembrane domain. This study thus provides a structural foundation for the understanding of the entire SLC26 family and potentially facilitates their therapeutic exploitation.https://elifesciences.org/articles/46986chloride transportalternate accesspatch clampcryo-EM |
spellingShingle | Justin D Walter Marta Sawicka Raimund Dutzler Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport eLife chloride transport alternate access patch clamp cryo-EM |
title | Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport |
title_full | Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport |
title_fullStr | Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport |
title_full_unstemmed | Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport |
title_short | Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport |
title_sort | cryo em structures and functional characterization of murine slc26a9 reveal mechanism of uncoupled chloride transport |
topic | chloride transport alternate access patch clamp cryo-EM |
url | https://elifesciences.org/articles/46986 |
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