Nav1.5 channels can reach the plasma membrane through distinct N-glycosylation states
| Autor: | Nicolas Bourmeyster, Aurélie Mercier, Romain Clément, Patrick Bois, Aurélien Chatelier, Thomas Harnois |
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| Přispěvatelé: | Signalisation et Transports Ioniques Membranaires (STIM), Université de Tours-Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Centre hospitalier universitaire de Poitiers (CHU Poitiers), Université de Poitiers-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2015 |
| Předmět: |
Glycosylation
Na(v)1.5 Biophysics N-glycosylation Secretory pathway 030204 cardiovascular system & hematology Nav1.5 Transfection Biochemistry Membrane Potentials NAV1.5 Voltage-Gated Sodium Channel 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine N-linked glycosylation Voltage-gated sodium channel Membrane activity Humans Brugada syndrome Molecular Biology 030304 developmental biology chemistry.chemical_classification 0303 health sciences Brefeldin A biology Sodium channel Cell Membrane [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry Molecular Biology/Molecular biology Negative dominance Cell biology Protein Transport HEK293 Cells Phenotype chemistry Mutation biology.protein Glycoprotein Protein Processing Post-Translational |
| Zdroj: | Biochimica et Biophysica Acta (BBA)-General Subjects Biochimica et Biophysica Acta (BBA)-General Subjects, Elsevier, 2015, 1850 (6), pp.1215-1223. ⟨10.1016/j.bbagen.2015.02.009⟩ |
| ISSN: | 0304-4165 |
| DOI: | 10.1016/j.bbagen.2015.02.009 |
| Popis: | Background Like many voltage-gated sodium channels, the cardiac isoform Nav1.5 is well known as a glycoprotein which necessarily undergoes N-glycosylation processing during its transit to the plasma membrane. In some cardiac disorders, especially the Brugada syndrome (BrS), mutations in Nav1.5 encoding gene lead to intracellular retention and consequently trafficking defect of these proteins. We used two BrS mutants as tools to clarify both Nav1.5 glycosylation states and associated secretory behaviors. Methods Patch-clamp recordings and surface biotinylation assays of HEK293T cells expressing wild-type (WT) and/or mutant Nav1.5 proteins were performed to assess the impact of mutant co-expression on the membrane activity and localization of WT channels. Enzymatic deglycosylation assays and brefeldin A (BFA) treatments were also employed to further characterize recombinant and native Nav1.5 maturation. Results The present data demonstrate that Nav1.5 channels mainly exist as two differentially glycosylated forms. We reveal that dominant negative effects induced by BrS mutants upon WT channel current result from the abnormal surface expression of the fully-glycosylated forms exclusively. Furthermore, we show that core-glycosylated channels can be found at the surface membrane of BFA-treated or untreated cells, but obviously without generating any sodium current. Conclusions Our findings provide evidence that native and recombinant Nav1.5 subunits are expressed as two distinct matured forms. Fully-glycosylated state of Nav1.5 seems to determine its functionality whereas core-glycosylated forms might be transported to the plasma membrane through an unconventional Golgi-independent secretory route. General significance This work highlights that N-linked glycosylation processing would be critical for Nav1.5 membrane trafficking and function. |
| Databáze: | OpenAIRE |
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