| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Long QT syndrome (LQT) is an electrophysiological disorder that can lead to sudden death from cardiac arrhythmias. One form of LQT has been attributed to mutations in the human ether-a-go-go-related gene (HERG) that encodes a voltage-gated cardiac K+ channel. While a recent report indicates that LQT in some patients is associated with a mutation of HERG at a consensus extracellular N-linked glycosylation site (N629), earlier studies failed to identify a role for N-linked glycosylation in the functional expression of voltage-gated K+ channels. In this study we used pharmacological agents and site-directed mutagenesis to assess the contribution of N-linked glycosylation to the surface localization of HERG channels.
Tunicamycin, an inhibitor of N-linked glycosylation, blocked normal surface membrane expression of a HERG-green fluorescent protein (GFP) fusion protein (HERGGFP) transiently expressed in human embryonic kidney (HEK 293) cells imaged with confocal microscopy.
Immunoblot analysis revealed that N-glycosidase F shifted the molecular mass of HERGGFP, stably expressed in HEK 293 cells, indicating the presence of N-linked carbohydrate moieties. Mutations at each of the two putative extracellular N-linked glycosylation sites (N598Q and N629Q) led to a perinuclear subcellular localization of HERGGFP stably expressed in HEK 293 cells, with no surface membrane expression. Furthermore, patch clamp analysis revealed that there was a virtual absence of HERG current in the N-glycosylation mutants.
Taken together, these results strongly suggest that N-linked glycosylation is required for surface membrane expression of HERG. These findings may provide insight into a mechanism responsible for LQT2 due to N-linked glycosylation-related mutations of HERG.
This article has been cited by other articles:
|
|
 |
|
  V. E. Walker, R. Atanasiu, H. Lam, and A. Shrier Co-chaperone FKBP38 Promotes HERG Trafficking J. Biol. Chem., August 10, 2007; 282(32): 23509 - 23516. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. B. Maryon, S. A. Molloy, and J. H. Kaplan O-Linked Glycosylation at Threonine 27 Protects the Copper Transporter hCTR1 from Proteolytic Cleavage in Mammalian Cells J. Biol. Chem., July 13, 2007; 282(28): 20376 - 20387. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Chen, O. Frohlich, Y. Yang, J. D. Klein, and J. M. Sands Loss of N-Linked Glycosylation Reduces Urea Transporter UT-A1 Response to Vasopressin J. Biol. Chem., September 15, 2006; 281(37): 27436 - 27442. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Xu, Y. Fu, W. Tian, and D. M. Cohen Glycosylation of the osmoresponsive transient receptor potential channel TRPV4 on Asn-651 influences membrane trafficking Am J Physiol Renal Physiol, May 1, 2006; 290(5): F1103 - F1109. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Sun, X. Liu, Q. Xiong, S. Shikano, and M. Li Chronic Inhibition of Cardiac Kir2.1 and hERG Potassium Channels by Celastrol with Dual Effects on Both Ion Conductivity and Protein Trafficking J. Biol. Chem., March 3, 2006; 281(9): 5877 - 5884. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Napp, F. Monje, W. Stuhmer, and L. A. Pardo Glycosylation of Eag1 (Kv10.1) Potassium Channels: INTRACELLULAR TRAFFICKING AND FUNCTIONAL CONSEQUENCES J. Biol. Chem., August 19, 2005; 280(33): 29506 - 29512. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Miranda, T. Giraldez, P. de la Pena, D. G Manso, C. Alonso-Ron, D. Gomez-Varela, P. Dominguez, and F. Barros Specificity of TRH receptor coupling to G-proteins for regulation of ERG K+ channels in GH3 rat anterior pituitary cells J. Physiol., August 1, 2005; 566(3): 717 - 736. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. P. Delisle, J. K. Slind, J. A. Kilby, C. L. Anderson, B. D. Anson, R. C. Balijepalli, D. J. Tester, M. J. Ackerman, T. J. Kamp, and C. T. January Intragenic Suppression of Trafficking-Defective KCNH2 Channels Associated with Long QT Syndrome Mol. Pharmacol., July 1, 2005; 68(1): 233 - 240. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. E. Clancy and R. S. Kass Inherited and Acquired Vulnerability to Ventricular Arrhythmias: Cardiac Na+ and K+ Channels Physiol Rev, January 1, 2005; 85(1): 33 - 47. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Tovar-Palacio, N. A. Bobadilla, P. Cortes, C. Plata, P. de los Heros, N. Vazquez, and G. Gamba Ion and diuretic specificity of chimeric proteins between apical Na+-K+-2Cl- and Na+-Cl- cotransporters Am J Physiol Renal Physiol, September 1, 2004; 287(3): F570 - F577. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. Folco, G.-X. Liu, and G. Koren Caveolin-3 and SAP97 form a scaffolding protein complex that regulates the voltage-gated potassium channel Kv1.5 Am J Physiol Heart Circ Physiol, August 1, 2004; 287(2): H681 - H690. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. P. Delisle, B. D. Anson, S. Rajamani, and C. T. January Biology of Cardiac Arrhythmias: Ion Channel Protein Trafficking Circ. Res., June 11, 2004; 94(11): 1418 - 1428. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. Faillace, R. O. Bernabeu, and J. I. Korenbrot Cellular Processing of Cone Photoreceptor Cyclic GMP-gated Ion Channels: A ROLE FOR THE S4 STRUCTURAL MOTIF J. Biol. Chem., May 21, 2004; 279(21): 22643 - 22653. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Thomas, J. Kiehn, H. A Katus, and C. A Karle Defective protein trafficking in hERG-associated hereditary long QT syndrome (LQT2): molecular mechanisms and restoration of intracellular protein processing Cardiovasc Res, November 1, 2003; 60(2): 235 - 241. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Much, C. Wahl-Schott, X. Zong, A. Schneider, L. Baumann, S. Moosmang, A. Ludwig, and M. Biel Role of Subunit Heteromerization and N-Linked Glycosylation in the Formation of Functional Hyperpolarization-activated Cyclic Nucleotide-gated Channels J. Biol. Chem., October 31, 2003; 278(44): 43781 - 43786. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Akhavan, R. Atanasiu, and A. Shrier Identification of a COOH-terminal Segment Involved in Maturation and Stability of Human Ether-a-go-go-related Gene Potassium Channels J. Biol. Chem., October 10, 2003; 278(41): 40105 - 40112. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Meade, R. S. Hoover, C. Plata, N. Vazquez, N. A. Bobadilla, G. Gamba, and S. C. Hebert cAMP-dependent activation of the renal-specific Na+-K+-2Cl- cotransporter is mediated by regulation of cotransporter trafficking Am J Physiol Renal Physiol, June 1, 2003; 284(6): F1145 - F1154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Shimoni and X.-F. Liu Role of PKC in autocrine regulation of rat ventricular K+ currents by angiotensin and endothelin Am J Physiol Heart Circ Physiol, April 1, 2003; 284 (4): H1168 - H1181. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. S. Hoover, E. Poch, A. Monroy, N. Vazquez, T. Nishio, G. Gamba, and S. C. Hebert N-Glycosylation at Two Sites Critically Alters Thiazide Binding and Activity of the Rat Thiazide-sensitive Na+:Cl- Cotransporter J. Am. Soc. Nephrol., February 1, 2003; 14(2): 271 - 282. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Jin, T. M. Weiger, and I. B. Levitan Reciprocal Modulation between the alpha and beta 4 Subunits of hSlo Calcium-dependent Potassium Channels J. Biol. Chem., November 8, 2002; 277(46): 43724 - 43729. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Kupershmidt, T. Yang, S. Chanthaphaychith, Z. Wang, J. A. Towbin, and D. M. Roden Defective Human Ether-a-go-go-related Gene Trafficking Linked to an Endoplasmic Reticulum Retention Signal in the C Terminus J. Biol. Chem., July 19, 2002; 277(30): 27442 - 27448. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. R. Conti, C. M. Radeke, and C. A. Vandenberg Membrane Targeting of ATP-sensitive Potassium Channel. EFFECTS OF GLYCOSYLATION ON SURFACE EXPRESSION J. Biol. Chem., July 5, 2002; 277(28): 25416 - 25422. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Gong, C. L. Anderson, C. T. January, and Z. Zhou Role of glycosylation in cell surface expression and stability of HERG potassium channels Am J Physiol Heart Circ Physiol, July 1, 2002; 283(1): H77 - H84. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Finley, Y. Li, F. Hua, J. Lillich, K. E. Mitchell, S. Ganta, R. F. Gilmour Jr., and L. C. Freeman Expression and coassociation of ERG1, KCNQ1, and KCNE1 potassium channel proteins in horse heart Am J Physiol Heart Circ Physiol, July 1, 2002; 283(1): H126 - H138. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Schwalbe, A. Rudin, S.-L. Xia, and C. S. Wingo Site-directed Glycosylation Tagging of Functional Kir2.1 Reveals That the Putative Pore-forming Segment Is Extracellular J. Biol. Chem., June 28, 2002; 277(27): 24382 - 24389. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Yan, J. Khoshnoodi, V. Ruotsalainen, and K. Tryggvason N-Linked Glycosylation Is Critical for the Plasma Membrane Localization of Nephrin J. Am. Soc. Nephrol., May 1, 2002; 13(5): 1385 - 1389. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. S. Cayabyab and L. C. Schlichter Regulation of an ERG K+ Current by Src Tyrosine Kinase J. Biol. Chem., April 12, 2002; 277(16): 13673 - 13681. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Ohya, K. Asakura, K. Muraki, M. Watanabe, and Y. Imaizumi Molecular and functional characterization of ERG, KCNQ, and KCNE subtypes in rat stomach smooth muscle Am J Physiol Gastrointest Liver Physiol, February 1, 2002; 282(2): G277 - G287. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. A. Ufret-Vincenty, D. J. Baro, and L. F. Santana Differential contribution of sialic acid to the function of repolarizing K+ currents in ventricular myocytes Am J Physiol Cell Physiol, August 1, 2001; 281(2): C464 - C474. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Baroudi, V. Pouliot, I. Denjoy, P. Guicheney, A. Shrier, and M. Chahine Novel Mechanism for Brugada Syndrome : Defective Surface Localization of an SCN5A Mutant (R1432G) Circ. Res., June 22, 2001; 88 (12): e78 - e83. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. E. Clancy and Y. Rudy Cellular consequences of HERG mutations in the long QT syndrome: precursors to sudden cardiac death Cardiovasc Res, May 1, 2001; 50(2): 301 - 313. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J.D. Morrissette, R. P. Colliton, and N. B. Spinner Defective intracellular transport and processing of JAG1 missense mutations in Alagille syndrome Hum. Mol. Genet., February 1, 2001; 10(4): 405 - 413. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Ficker, D. Thomas, P. C. Viswanathan, A. T. Dennis, S. G. Priori, C. Napolitano, M. Memmi, B. A. Wible, E. S. Kaufman, S. Iyengar, et al. Novel characteristics of a misprocessed mutant HERG channel linked to hereditary long QT syndrome Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H1748 - H1756. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. L. Pond, B. K. Scheve, A. T. Benedict, K. Petrecca, D. R. Van Wagoner, A. Shrier, and J. M. Nerbonne Expression of Distinct ERG Proteins in Rat, Mouse, and Human Heart. RELATION TO FUNCTIONAL IKr CHANNELS J. Biol. Chem., February 25, 2000; 275(8): 5997 - 6006. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. M Roden and J. R Balser A plethora of mechanisms in the HERG-related long QT syndrome: Genetics meets electrophysiology Cardiovasc Res, November 1, 1999; 44(2): 242 - 246. [Full Text] [PDF]
|
|
|
|
|
|
R. Khanna, M. P. Myers, M. Laine, and D. M. Papazian Glycosylation Increases Potassium Channel Stability and Surface Expression in Mammalian Cells J. Biol. Chem., August 31, 2001; 276(36): 34028 - 34034. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
