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Dynamitin affects cell-surface expression of voltage-gated sodium channel Nav1.5.
- Source :
-
The Biochemical journal [Biochem J] 2014 Nov 01; Vol. 463 (3), pp. 339-49. - Publication Year :
- 2014
-
Abstract
- 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.
- Subjects :
- Animals
Binding Sites
Dynactin Complex
HEK293 Cells
Humans
Mice, Inbred BALB C
Microtubule-Associated Proteins genetics
Myocardium metabolism
Myocytes, Cardiac metabolism
NAV1.5 Voltage-Gated Sodium Channel genetics
Protein Structure, Tertiary
Two-Hybrid System Techniques
Microtubule-Associated Proteins metabolism
NAV1.5 Voltage-Gated Sodium Channel metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1470-8728
- Volume :
- 463
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Biochemical journal
- Publication Type :
- Academic Journal
- Accession number :
- 25088759
- Full Text :
- https://doi.org/10.1042/BJ20140604