Dynamitin affects cell-surface expression of voltage-gated sodium channel Nav1.5
| Autor: | Françoise Le Bouffant, Anne Laure Gamblin, Benoit Chatin, Marie Allouis, Pauline Colombier |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Multiprotein complex
Microtubule-associated protein Dynein Nav1.5 Biochemistry NAV1.5 Voltage-Gated Sodium Channel Microtubule Two-Hybrid System Techniques Animals Humans Myocytes Cardiac Molecular Biology Mice Inbred BALB C Binding Sites biology Sodium channel Myocardium Cell Biology Dynactin Complex Cell biology Protein Structure Tertiary HEK293 Cells biology.protein Dynactin Microtubule-Associated Proteins Intracellular |
| Zdroj: | The Biochemical journal. 463(3) |
| ISSN: | 1470-8728 |
| Popis: | The major cardiac voltage-gated sodium channel Nav1.5 associates with proteins that regulate its biosynthesis, localization, activity and degradation. Identification of partner proteins is crucial for a better understanding of the channel regulation. Using a yeast two-hybrid screen, we identified dynamitin as a Nav1.5-interacting protein. Dynamitin is part of the microtubule-binding multiprotein complex dynactin. When overexpressed it is a potent inhibitor of dynein/kinesin-mediated transport along the microtubules by disrupting the dynactin complex and dissociating cargoes from microtubules. The use of deletion constructs showed that the C-terminal domain of dynamitin is essential for binding to the first intracellular interdomain of Nav1.5. Co-immunoprecipitation assays confirmed the association between Nav1.5 and dynamitin in mouse heart extracts. Immunostaining experiments showed that dynamitin and Nav1.5 co-localize at intercalated discs of mouse cardiomyocytes. The whole-cell patch-clamp technique was applied to test the functional link between Nav1.5 and dynamitin. Dynamitin overexpression in HEK-293 (human embryonic kidney 293) cells expressing Nav1.5 resulted in a decrease in sodium current density in the membrane with no modification of the channel-gating properties. Biotinylation experiments produced similar information with a reduction in Nav1.5 at the cell surface when dynactin-dependent transport was inhibited. The present study strongly suggests that dynamitin is involved in the regulation of Nav1.5 cell-surface density. |
| Databáze: | OpenAIRE |
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