Electrophysiological properties of mouse and epitope-tagged human cardiac sodium channel Nav1.5 expressed in HEK293 cells

• Published in: F1000 research 2013-04, Vol.2, p.48
• Main Authors: Reinhard, Katja, Rougier, Jean-Sébastien, Ogrodnik, Jakob, Abriel, Hugues
• Format: Article
• Language: English
• Subjects: Animal Genetics; Cardiovascular Physiology/Circulation
• ISSN: 2046-1402; 2046-1402
• DOI: 10.12688/f1000research.2-48.v2

Background: The pore-forming subunit of the cardiac sodium channel, Na v 1.5, has been previously found to be mutated in genetically determined arrhythmias. Na v 1.5 associates with many proteins that regulate its function and cellular localisation. In order to identify more in situ Na v 1.5 interacting proteins, genetically-modified mice with a high-affinity epitope in the sequence of Na v 1.5 can be generated. Methods: In this short study, we (1) compared the biophysical properties of the sodium current (I Na ) generated by the mouse Na v 1.5 (mNa v 1.5) and human Na v 1.5 (hNa v 1.5) constructs that were expressed in HEK293 cells, and (2) investigated the possible alterations of the biophysical properties of the human Na v 1.5 construct that was modified with specific epitopes. Results: The biophysical properties of mNa v 1.5 were similar to the human homolog. Addition of epitopes either up-stream of the N-terminus of hNa v 1.5 or in the extracellular loop between the S5 and S6 transmembrane segments of domain 1, significantly decreased the amount of I Na and slightly altered its biophysical properties. Adding green fluorescent protein (GFP) to the N-terminus did not modify any of the measured biophysical properties of hNa v 1.5. Conclusions: These findings have to be taken into account when planning to generate genetically-modified mouse models that harbour specific epitopes in the gene encoding mNa v 1.5.