Published online before print April 8, 2004, doi: 10.1161/01.RES.0000127621.54132.AE
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on October 27, 2003
Revised on March 25, 2004
Accepted on March 29, 2004
Localization of Pacemaker Channels in Lipid Rafts Regulates Channel Kinetics
Andrea Barbuti ;
From the Department of Biomolecular Sciences and Biotechnology (A.B., B.G., M.R., R.M., B.T., D.D.), Laboratory of Molecular Physiology and Neurobiology, University of Milano; and INFM-Milano U. Unit (D.D.), Milano, Italy.
* To whom correspondence should be addressed. E-mail: dario.difrancesco{at}unimi.it.
Lipid rafts are discrete membrane subdomains rich in sphingolipids and cholesterol. In ventricular myocytes a function of caveolae, a type of lipid rafts, is to concentrate in close proximity several proteins of the 
-adrenergic transduction pathway. We have investigated the subcellular localization of HCN4 channels expressed in HEK cells and studied the effects of such localization on the properties of pacemaker channels in HEK and rabbit sinoatrial (SAN) cells. We used a discontinuous sucrose gradient and Western blot analysis to detect HCN4 proteins in HEK and in SAN cells, and found that HCN4 proteins localize to low-density membrane fractions together with flotillin (HEK) or caveolin-3 (SAN), structural proteins of caveolae. Lipid raft disruption by cell incubation with Methyl--Cyclodextrin (MCD) impaired specific HCN4 localization. It also shifted the midpoint of activation of the HCN4 current in HEK cells and of If in SAN cells to the positive direction by 11.9 and 10.4 mV, respectively. These latter effects were not due to elevation of basal cyclic nucleotide levels because the cholesterol-depletion treatment did not alter the current response to cyclic nucleotides. In accordance with an increased If, MCD-treated SAN cells showed large increases of diastolic depolarization slope (87%) and rate (58%). We also found that the kinetics of HCN4- and native f-channel deactivation were slower after lipid raft disorganization. In conclusion, our work indicates that pacemaker channels localize to lipid rafts and that disruption of lipid rafts causes channels to redistribute within the membrane and modifies their kinetic properties.
Key words: HCN channels • pacemaker current • lipid rafts • caveolin • sinoatrial node
This article has been cited by other articles:
 |
|
 |
|
  M. Biel, C. Wahl-Schott, S. Michalakis, and X. Zong Hyperpolarization-Activated Cation Channels: From Genes to Function Physiol Rev, July 1, 2009; 89(3): 847 - 885. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. P. McEwen and J. R. Martens Antifibrillatory Agents and Potassium Channels in the Atria: Pore Block versus Channel Trafficking Mol. Interv., April 1, 2009; 9(2): 79 - 86. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Garg, J. Jiao, and K. Hu Regulation of ATP-sensitive K+ channels by caveolin-enriched microdomains in cardiac myocytes Cardiovasc Res, April 1, 2009; 82(1): 51 - 58. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Mangoni and J. Nargeot Genesis and Regulation of the Heart Automaticity Physiol Rev, July 1, 2008; 88(3): 919 - 982. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Younes, A. E. Lyashkov, D. Graham, A. Sheydina, M. V. Volkova, M. Mitsak, T. M. Vinogradova, Y. O. Lukyanenko, Y. Li, A. M. Ruknudin, et al. Ca2+-stimulated Basal Adenylyl Cyclase Activity Localization in Membrane Lipid Microdomains of Cardiac Sinoatrial Nodal Pacemaker Cells J. Biol. Chem., May 23, 2008; 283(21): 14461 - 14468. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. P. McEwen, Q. Li, S. Jackson, P. M. Jenkins, and J. R. Martens Caveolin Regulates Kv1.5 Trafficking to Cholesterol-Rich Membrane Microdomains Mol. Pharmacol., March 1, 2008; 73(3): 678 - 685. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Langlois, K. N. Cowan, Q. Shao, B. J. Cowan, and D. W. Laird Caveolin-1 and -2 Interact with Connexin43 and Regulate Gap Junctional Intercellular Communication in Keratinocytes Mol. Biol. Cell, March 1, 2008; 19(3): 912 - 928. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-H. Li, Q. Zhang, B. Teng, S. J. Mustafa, J.-Y. Huang, and H.-G. Yu Src tyrosine kinase alters gating of hyperpolarization-activated HCN4 pacemaker channel through Tyr531 Am J Physiol Cell Physiol, January 1, 2008; 294(1): C355 - C362. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Tsujikawa, Y. Song, M. Watanabe, H. Masumiya, S. A. Gupte, R. Ochi, and T. Okada Cholesterol depletion modulates basal L-type Ca2+ current and abolishes its -adrenergic enhancement in ventricular myocytes Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H285 - H292. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. J. Mohler and X. H. T. Wehrens Mechanisms of Human Arrhythmia Syndromes: Abnormal Cardiac Macromolecular Interactions Physiology, October 1, 2007; 22(5): 342 - 350. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Abi-Char, A. Maguy, A. Coulombe, E. Balse, P. Ratajczak, J.-L. Samuel, S. Nattel, and S. N. Hatem Membrane cholesterol modulates Kv1.5 potassium channel distribution and function in rat cardiomyocytes J. Physiol., August 1, 2007; 582(3): 1205 - 1217. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Knaus, X. Zong, N. Beetz, R. Jahns, M. J. Lohse, M. Biel, and L. Hein Direct Inhibition of Cardiac Hyperpolarization-Activated Cyclic Nucleotide-Gated Pacemaker Channels by Clonidine Circulation, February 20, 2007; 115(7): 872 - 880. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Hinzpeter, J. Fritsch, F. Borot, S. Trudel, D.-L. Vieu, F. Brouillard, M. Baudouin-Legros, J. Clain, A. Edelman, and M. Ollero Membrane Cholesterol Content Modulates ClC-2 Gating and Sensitivity to Oxidative Stress J. Biol. Chem., January 26, 2007; 282(4): 2423 - 2432. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Vatta, M. J. Ackerman, B. Ye, J. C. Makielski, E. E. Ughanze, E. W. Taylor, D. J. Tester, R. C. Balijepalli, J. D. Foell, Z. Li, et al. Mutant Caveolin-3 Induces Persistent Late Sodium Current and Is Associated With Long-QT Syndrome Circulation, November 14, 2006; 114(20): 2104 - 2112. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P. Dekker and G. Yellen Cooperative Gating between Single HCN Pacemaker Channels J. Gen. Physiol., November 1, 2006; 128(5): 561 - 567. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. C. Balijepalli, J. D. Foell, D. D. Hall, J. W. Hell, and T. J. Kamp From the Cover: Localization of cardiac L-type Ca2+ channels to a caveolar macromolecular signaling complex is required for beta2-adrenergic regulation PNAS, May 9, 2006; 103(19): 7500 - 7505. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Maguy, T. E. Hebert, and S. Nattel Involvement of lipid rafts and caveolae in cardiac ion channel function Cardiovasc Res, March 1, 2006; 69(4): 798 - 807. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Calaghan and E. White Caveolae modulate excitation-contraction coupling and {beta}2-adrenergic signalling in adult rat ventricular myocytes Cardiovasc Res, March 1, 2006; 69(4): 816 - 824. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Qu, Y. Kryukova, I. A. Potapova, S. V. Doronin, M. Larsen, G. Krishnamurthy, I. S. Cohen, and R. B. Robinson MiRP1 Modulates HCN2 Channel Expression and Gating in Cardiac Myocytes J. Biol. Chem., October 15, 2004; 279(42): 43497 - 43502. [Abstract] [Full Text] [PDF]
|
|