» Articles » PMID: 19797425

Na+ Channel Regulation by Ca2+/calmodulin and Ca2+/calmodulin-dependent Protein Kinase II in Guinea-pig Ventricular Myocytes

Overview
Journal Cardiovasc Res
Date 2009 Oct 3
PMID 19797425
Citations 60
Authors
Affiliations
Soon will be listed here.
Abstract

Aims: Calmodulin (CaM) regulates Na+ channel gating through binding to an IQ-like motif in the C-terminus. Ca2+/CaM-dependent protein kinase II (CaMKII) regulates Ca2+ handling, and chronic overactivity of CaMKII is associated with left ventricular hypertrophy and dysfunction and lethal arrhythmias. However, the acute effects of Ca2+/CaM and CaMKII on cardiac Na+ channels are not fully understood.

Methods And Results: Purified Na(V)1.5-glutathione-S-transferase fusion peptides were phosphorylated in vitro by CaMKII predominantly on the I-II linker. Whole-cell voltage-clamp was used to measure Na+ current (I(Na)) in isolated guinea-pig ventricular myocytes in the absence or presence of CaM or CaMKII in the pipette solution. CaMKII shifted the voltage dependence of Na+ channel availability by approximately +5 mV, hastened recovery from inactivation, decreased entry into intermediate or slow inactivation, and increased persistent (late) current, but did not change I(Na) decay. These CaMKII-induced changes of Na+ channel gating were completely abolished by a specific CaMKII inhibitor, autocamtide-2-related inhibitory peptide (AIP). Ca2+/CaM alone reproduced the CaMKII-induced changes of I(Na) availability and the fraction of channels undergoing slow inactivation, but did not alter recovery from inactivation or the magnitude of the late current. Furthermore, the CaM-induced changes were also completely abolished by AIP. On the other hand, cAMP-dependent protein kinase A inhibitors did not abolish the CaM/CaMKII-induced alterations of I(Na) function.

Conclusion: Ca2+/CaM and CaMKII have distinct effects on the inactivation phenotype of cardiac Na+ channels. The differences are consistent with CaM-independent effects of CaMKII on cardiac Na+ channel gating.

Citing Articles

Knock-in swine model reveals new arrhythmia mechanism in Timothy syndrome.

Boukens B, Verkerk A, Bezzina C Nat Cardiovasc Res. 2024; 3(1):18-20.

PMID: 39195890 DOI: 10.1038/s44161-023-00408-6.


BIOLOGICAL ANTIARRHYTHMICS-SODIUM CHANNEL INTERACTING PROTEINS.

Tomaselli G Trans Am Clin Climatol Assoc. 2023; 133:136-148.

PMID: 37701589 PMC: 10493736.


CaMKII Inhibition Attenuates Distinct Gain-of-Function Effects Produced by Mutant Nav1.6 Channels and Reduces Neuronal Excitability.

Zybura A, Sahoo F, Hudmon A, Cummins T Cells. 2022; 11(13).

PMID: 35805192 PMC: 9266207. DOI: 10.3390/cells11132108.


Fibroblast growth factor homologous factors serve as a molecular rheostat in tuning arrhythmogenic cardiac late sodium current.

Chakouri N, Rivas S, Roybal D, Yang L, Diaz J, Hsu A Nat Cardiovasc Res. 2022; 1(5):1-13.

PMID: 35662881 PMC: 9161660. DOI: 10.1038/s44161-022-00060-6.


Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going?.

Horvath B, Szentandrassy N, Almassy J, Dienes C, Kovacs Z, Nanasi P Pharmaceuticals (Basel). 2022; 15(2).

PMID: 35215342 PMC: 8879921. DOI: 10.3390/ph15020231.


References
1.
Maier L, Bers D . Calcium, calmodulin, and calcium-calmodulin kinase II: heartbeat to heartbeat and beyond. J Mol Cell Cardiol. 2002; 34(8):919-39. DOI: 10.1006/jmcc.2002.2038. View

2.
Hoppe U, Johns D, Marban E, ORourke B . Manipulation of cellular excitability by cell fusion: effects of rapid introduction of transient outward K+ current on the guinea pig action potential. Circ Res. 1999; 84(8):964-72. DOI: 10.1161/01.res.84.8.964. View

3.
Wang W, Zhu W, Wang S, Yang D, Crow M, Xiao R . Sustained beta1-adrenergic stimulation modulates cardiac contractility by Ca2+/calmodulin kinase signaling pathway. Circ Res. 2004; 95(8):798-806. DOI: 10.1161/01.RES.0000145361.50017.aa. View

4.
Kim J, Ghosh S, Liu H, Tateyama M, Kass R, Pitt G . Calmodulin mediates Ca2+ sensitivity of sodium channels. J Biol Chem. 2004; 279(43):45004-12. DOI: 10.1074/jbc.M407286200. View

5.
Wu Y, Temple J, Zhang R, Dzhura I, Zhang W, Trimble R . Calmodulin kinase II and arrhythmias in a mouse model of cardiac hypertrophy. Circulation. 2002; 106(10):1288-93. DOI: 10.1161/01.cir.0000027583.73268.e7. View