Burel, Sophie and Coyan, Fabien C. and Lorenzini, Maxime and Meyer, Matthew R. and Lichti, Cheryl F. and Brown, Joan H. and Loussouarn, Gildas and Charpentier, Flavien and Nerbonne, Jeanne M. and Townsend, R. Reid and Maier, Lars S. and Marionneau, Celine (2017) C-terminal phosphorylation of Na(V)1.5 impairs FGF13-dependent regulation of channel inactivation. JOURNAL OF BIOLOGICAL CHEMISTRY, 292 (42). pp. 17431-17448. ISSN 0021-9258, 1083-351X
Full text not available from this repository. (Request a copy)Abstract
Voltage-gated Na+ (Na-V) channels are key regulators of myocardial excitability, and Ca2+/calmodulin-dependent protein kinase II (CaMKII)-dependent alterations in Na(V)1.5 channel inactivation are emerging as a critical determinant of arrhythmias in heart failure. However, the global native phosphorylation pattern of Na(V)1.5 subunits associated with these arrhythmogenic disorders and the associated channel regulatory defects remain unknown. Here, we undertook phosphoproteomic analyses to identify and quantify in situ the phosphorylation sites in the Na(V)1.5 proteins purified from adult WT and failing CaMKII delta(c)-overexpressing (CaMKII delta(c)-Tg) mouse ventricles. Of 19 native Na(V)1.5 phosphorylation sites identified, two C-terminal phosphoserines at positions 1938 and 1989 showed increased phosphorylation in the CaMKII delta(c)-Tg compared with the WT ventricles. Wethen tested the hypothesis that phosphorylation at these two sites impairs fibroblast growth factor 13 (FGF13)-dependent regulation of Na(V)1.5 channel inactivation. Whole-cell voltage-clamp analyses in HEK293 cells demonstrated that FGF13 increases Na(V)1.5 channel availability and decreases late Na+ current, two effects that were abrogated with Na(V)1.5 mutants mimicking phosphorylation at both sites. Additional co-immunoprecipitation experiments revealed that FGF13 potentiates the binding of calmodulin to Na(V)1.5 and that phosphomimetic mutations at both sites decrease the interaction of FGF13 and, consequently, of calmodulin with Na(V)1.5. Together, we have identified two novel native phosphorylation sites in the C terminus of Na(V)1.5 that impair FGF13-dependent regulation of channel inactivation and may contribute to CaMKII delta(c)-dependent arrhythmogenic disorders in failing hearts.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | FACTOR HOMOLOGOUS FACTOR; LATE SODIUM CURRENT; HEART-FAILURE; KINASE-II; MASS-SPECTROMETRY; NA+ CHANNELS; QUANTITATIVE-ANALYSIS; MEMBRANE-PROTEINS; STATISTICAL-MODEL; CRYSTAL-STRUCTURE; |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Innere Medizin II |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2018 13:19 |
| Last Modified: | 28 Feb 2019 10:52 |
| URI: | https://pred.uni-regensburg.de/id/eprint/1992 |
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