CaMKII Modulates the Cardiac Transient Outward K + Current through its Association with Kv4 Channels in Non-Caveolar Membrane Rafts
To test whether the physiological regulation of the cardiac Kv4 channels by the Ca /calmodulin-dependent protein kinase II (CaMKII) is restricted to lipid rafts and whether the interactions observed in rat cardiomyocytes also occur in the human ventricle. Ventricular myocytes were freshly isolated f...
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Published in | Cellular physiology and biochemistry Vol. 54; no. 1; pp. 27 - 39 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Germany
Cell Physiol Biochem Press GmbH & Co KG
15.01.2020
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Subjects | |
Online Access | Get full text |
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Summary: | To test whether the physiological regulation of the cardiac Kv4 channels by the Ca
/calmodulin-dependent protein kinase II (CaMKII) is restricted to lipid rafts and whether the interactions observed in rat cardiomyocytes also occur in the human ventricle.
Ventricular myocytes were freshly isolated from Sprague-Dawley rats. I
was recorded by the whole-cell Patch-Clamp technique. Membrane rafts were isolated by centrifugation in a discontinuous sucrose density gradient. The presence of the proteins of interest was analysed by western blot. Immunogold staining and electron microscopy of heart vibrosections was performed to localize Kv4.2/Kv4.3 and CaMKII proteins. Protein-protein interactions were determined by co-immunoprecipitation experiments in rat and human ventricular mycoytes.
Patch-Clamp recordings in control conditions and after lipid raft or caveolae disruption show that the CaMKII-Kv4 channel complex must associate in non-caveolar lipid rafts to be functional. Separation in density gradients, co-immunoprecipitation and electron microscopy show that there are two Kv4 channel populations: one located in caveolae, that is CaMKII independent, and another one located in planar membrane rafts, which is bound to CaMKII.
CaMKII regulates only the Kv4 channel population located in non-caveolar lipid rafts. Thus, the regulation of cardiac Kv4 channels in rat and human ventricle depends on their subcellular localization. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1015-8987 1421-9778 1015-8987 |
DOI: | 10.33594/000000203 |