1
|
Abriel H, Rougier JS, Jalife J. Ion channel macromolecular complexes in cardiomyocytes: roles in sudden cardiac death. Circ Res 2015; 116:1971-88. [PMID: 26044251 DOI: 10.1161/circresaha.116.305017] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The movement of ions across specific channels embedded on the membrane of individual cardiomyocytes is crucial for the generation and propagation of the cardiac electric impulse. Emerging evidence over the past 20 years strongly suggests that the normal electric function of the heart is the result of dynamic interactions of membrane ion channels working in an orchestrated fashion as part of complex molecular networks. Such networks work together with exquisite temporal precision to generate each action potential and contraction. Macromolecular complexes play crucial roles in transcription, translation, oligomerization, trafficking, membrane retention, glycosylation, post-translational modification, turnover, function, and degradation of all cardiac ion channels known to date. In addition, the accurate timing of each cardiac beat and contraction demands, a comparable precision on the assembly and organizations of sodium, calcium, and potassium channel complexes within specific subcellular microdomains, where physical proximity allows for prompt and efficient interaction. This review article, part of the Compendium on Sudden Cardiac Death, discusses the major issues related to the role of ion channel macromolecular assemblies in normal cardiac electric function and the mechanisms of arrhythmias leading to sudden cardiac death. It provides an idea of how these issues are being addressed in the laboratory and in the clinic, which important questions remain unanswered, and what future research will be needed to improve knowledge and advance therapy.
Collapse
Affiliation(s)
- Hugues Abriel
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - Jean-Sébastien Rougier
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - José Jalife
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.).
| |
Collapse
|
2
|
Takechi M, Wada T, Yagi H, Masuko T, Kawabata A. Ouabain exerts cytoprotection by diminishing the intracellular K(+) concentration increase caused by distinct stimuli in human leukemic cells. J Pharm Pharmacol 2014; 67:126-32. [PMID: 25208542 DOI: 10.1111/jphp.12317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 08/03/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES We tested if modulation of cytosolic K(+) levels by ouabain, an inhibitor of Na(+) /K(+) -ATPase, exerts cytoprotection against distinct stressful stimuli in human leukemic cells. METHODS The cytosolic K(+) , Na(+) or Ca(2+) levels and the cytotoxicity were evaluated by flow cytometry. KEY FINDINGS Various cytotoxic chemicals and ultraviolet irradiation induced cell death and increased intracellular concentrations of K(+) , Na(+) or Ca(2+) . Ouabain reduced the cytotoxicity and the elevation of cytosolic levels of K(+) but not those of Na(+) or Ca(2+) . CONCLUSIONS Our data thus suggest that elevated cytosolic K(+) levels are associated with the cytotoxicity in response to distinct stressful stimuli and that ouabain exerts cytoprotection most probably by regulating intracellular K(+) levels.
Collapse
Affiliation(s)
- Masayuki Takechi
- Faculty of Pharmacy, Kinki University, Higashiosaka, Osaka, Japan
| | | | | | | | | |
Collapse
|
3
|
Zhang YH, Wu W, Sun HY, Deng XL, Cheng LC, Li X, Tse HF, Lau CP, Li GR. Modulation of human cardiac transient outward potassium current by EGFR tyrosine kinase and Src-family kinases. Cardiovasc Res 2011; 93:424-33. [PMID: 22198508 DOI: 10.1093/cvr/cvr347] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
AIMS The human cardiac transient outward K(+) current I(to) (encoded by Kv4.3 or KCND3) plays an important role in phase 1 rapid repolarization of cardiac action potentials in the heart. However, modulation of I(to) by intracellular signal transduction is not fully understood. The present study was therefore designed to determine whether/how human atrial I(to) and hKv4.3 channels stably expressed in HEK 293 cells are regulated by protein tyrosine kinases (PTKs). METHODS AND RESULTS Whole-cell patch voltage-clamp, immunoprecipitation, western blotting, and site-directed mutagenesis approaches were employed in the present study. We found that human atrial I(to) was inhibited by the broad-spectrum PTK inhibitor genistein, the selective epidermal growth factor receptor (EGFR) kinase inhibitor AG556, and the Src-family kinases inhibitor PP2. The inhibitory effect was countered by the protein tyrosine phosphatase inhibitor orthovanadate. In HEK 293 cells stably expressing human KCND3, genistein, AG556, and PP2 significantly reduced the hKv4.3 current, and the reduction was antagonized by orthovanadate. Interestingly, orthovanadate also reversed the reduced tyrosine phosphorylation level of hKv4.3 channels by genistein, AG556, or PP2. Mutagenesis revealed that the hKv4.3 mutant Y136F lost the inhibitory response to AG556, while Y108F lost response to PP2. The double-mutant Y108F-Y136F hKv4.3 channels showed no response to either AG556 or PP2. CONCLUSION Our results demonstrate that human atrial I(to) and cloned hKv4.3 channels are modulated by EGFR kinase via phosphorylation of the Y136 residue and by Src-family kinases via phosphorylation of the Y108 residue; tyrosine phosphorylation of the channel may be involved in regulating cardiac electrophysiology.
Collapse
Affiliation(s)
- Yan-Hui Zhang
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, L4-59, Laboratory Block, FMB, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Chen PS, Ai T. Is c-Src tyrosine kinase a new target for antiarrhythmic drug therapy? J Am Coll Cardiol 2011; 58:2340-1. [PMID: 22093513 DOI: 10.1016/j.jacc.2011.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 09/05/2011] [Indexed: 10/15/2022]
|
5
|
Zhang DY, Wu W, Deng XL, Lau CP, Li GR. Genistein and tyrphostin AG556 inhibit inwardly-rectifying Kir2.1 channels expressed in HEK 293 cells via protein tyrosine kinase inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1993-9. [DOI: 10.1016/j.bbamem.2011.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 04/13/2011] [Accepted: 04/29/2011] [Indexed: 11/28/2022]
|
6
|
Kim HJ, Ahn HS, Choi BH, Hahn SJ. Inhibition of Kv4.3 by genistein via a tyrosine phosphorylation-independent mechanism. Am J Physiol Cell Physiol 2010; 300:C567-75. [PMID: 21148405 DOI: 10.1152/ajpcell.00031.2010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effects of genistein, a protein tyrosine kinase (PTK) inhibitor, on voltage-dependent K(+) (Kv) 4.3 channel were examined using the whole cell patch-clamp techniques. Genistein inhibited Kv4.3 in a reversible, concentration-dependent manner with an IC(50) of 124.78 μM. Other PTK inhibitors (tyrphostin 23, tyrphostin 25, lavendustin A) had no effect on genistein-induced inhibition of Kv4.3. Orthovanadate, an inhibitor of protein phosphatases, did not reverse the inhibition of Kv4.3 by genistein. We also tested the effects of two inactive structural analogs: genistin and daidzein. Whereas Kv4.3 was unaffected by genistin, daidzein inhibited Kv4.3, albeit with a lower potency. Genistein did not affect the activation and inactivation kinetics of Kv4.3. Genistein-induced inhibition of Kv4.3 was voltage dependent with a steep increase over the channel opening voltage range. In the full-activation voltage range positive to +20 mV, no voltage-dependent inhibition was found. Genistein had no significant effect on steady-state activation, but shifted the voltage dependence of the steady-state inactivation of Kv4.3 in the hyperpolarizing direction in a concentration-dependent manner. The K(i) for the interaction between genistein and the inactivated state of Kv4.3, which was estimated from the concentration-dependent shift in the steady-state inactivation curve, was 1.17 μM. Under control conditions, closed-state inactivation was fitted to a single exponential function, and genistein accelerated closed-state inactivation. Genistein induced a weak use-dependent inhibition. These results suggest that genistein directly inhibits Kv4.3 by interacting with the closed-inactivated state of Kv4.3 channels. This effect is not mediated via inhibition of the PTK activity, because other types of PTK inhibitors could not prevent the inhibitory action of genistein.
Collapse
Affiliation(s)
- Hee Jae Kim
- Dept. of Physiology, College of Medicine, The Catholic Univ. of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, Korea
| | | | | | | |
Collapse
|
7
|
Cerda O, Trimmer JS. Analysis and functional implications of phosphorylation of neuronal voltage-gated potassium channels. Neurosci Lett 2010; 486:60-7. [PMID: 20600597 DOI: 10.1016/j.neulet.2010.06.064] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 06/16/2010] [Accepted: 06/22/2010] [Indexed: 11/30/2022]
Abstract
Phosphorylation is the most common and abundant post-translational modification to eukaryotic proteins, regulating a plethora of dynamic cellular processes. Here, we review and discuss recent advances in our knowledge of the breadth and importance of reversible phosphorylation in regulating the expression, localization and function of mammalian neuronal voltage-gated potassium (Kv) channels, key regulators of neuronal function. We highlight the role of modern mass spectrometric techniques and phosphospecific antibodies in revealing the extent and nature of phosphorylation at specific sites in Kv channels. We also emphasize the role of reversible phosphorylation in dynamically regulating diverse aspects of Kv channel biology. Finally, we discuss as important future directions the determination of the mechanistic basis for how altering phosphorylation state affects Kv channel expression, localization and function, the nature of macromolecular signaling complexes containing Kv channels and enzymes regulating their phosphorylation state, and the specific role of Kv channel phosphorylation in regulating neuronal function during physiological and pathophysiological events.
Collapse
Affiliation(s)
- Oscar Cerda
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616-8519, United States
| | | |
Collapse
|
8
|
Li GR, Dong MQ. Pharmacology of Cardiac Potassium Channels. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:93-134. [DOI: 10.1016/s1054-3589(10)59004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
9
|
Niwa N, Nerbonne JM. Molecular determinants of cardiac transient outward potassium current (I(to)) expression and regulation. J Mol Cell Cardiol 2009; 48:12-25. [PMID: 19619557 DOI: 10.1016/j.yjmcc.2009.07.013] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 06/25/2009] [Accepted: 07/10/2009] [Indexed: 12/21/2022]
Abstract
Rapidly activating and inactivating cardiac transient outward K(+) currents, I(to), are expressed in most mammalian cardiomyocytes, and contribute importantly to the early phase of action potential repolarization and to plateau potentials. The rapidly recovering (I(t)(o,f)) and slowly recovering (I(t)(o,s)) components are differentially expressed in the myocardium, contributing to regional heterogeneities in action potential waveforms. Consistent with the marked differences in biophysical properties, distinct pore-forming (alpha) subunits underlie the two I(t)(o) components: Kv4.3/Kv4.2 subunits encode I(t)(o,f), whereas Kv1.4 encodes I(t)(o,s), channels. It has also become increasingly clear that cardiac I(t)(o) channels function as components of macromolecular protein complexes, comprising (four) Kvalpha subunits and a variety of accessory subunits and regulatory proteins that influence channel expression, biophysical properties and interactions with the actin cytoskeleton, and contribute to the generation of normal cardiac rhythms. Derangements in the expression or the regulation of I(t)(o) channels in inherited or acquired cardiac diseases would be expected to increase the risk of potentially life-threatening cardiac arrhythmias. Indeed, a recently identified Brugada syndrome mutation in KCNE3 (MiRP2) has been suggested to result in increased I(t)(o,f) densities. Continued focus in this area seems certain to provide new and fundamentally important insights into the molecular determinants of functional I(t)(o) channels and into the molecular mechanisms involved in the dynamic regulation of I(t)(o) channel functioning in the normal and diseased myocardium.
Collapse
Affiliation(s)
- Noriko Niwa
- Department of Developmental Biology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8103, St. Louis, MO 63110-1093, USA
| | | |
Collapse
|