Identification and functional characterization of the human ether-a-go-go-related gene Q738X mutant associated with hereditary long QT syndrome type 2

Han,Sheng-Na; Yang,Song-Hua; Zhang,Yu; Sun,Xiao-Yan; Duan,Yan-Yan; Hu,Xiang-Jie; Fan,Tian-Li; Huang,Chen-Zheng; Yang,Ge; Zhang,Zhao; Zhang,Lirong

doi:10.3892/ijmm.2014.1827

Identification and functional characterization of the human ether-a-go-go-related gene Q738X mutant associated with hereditary long QT syndrome type 2

Authors:
- Sheng-Na Han
- Song-Hua Yang
- Yu Zhang
- Xiao-Yan Sun
- Yan-Yan Duan
- Xiang-Jie Hu
- Tian-Li Fan
- Chen-Zheng Huang
- Ge Yang
- Zhao Zhang
- Lirong Zhang
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Affiliations: Department of Pharmacology, School of Medicine, Zhengzhou University, Zhengzhou, Henan, P.R. China, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, P.R. China, Pharmacy College of Zhengzhou Railway Vocational and Technical College, Zhengzhou, Henan, P.R. China, Jiangsu Province Key Laboratory for Molecular Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, P.R. China
Published online on: July 1, 2014 https://doi.org/10.3892/ijmm.2014.1827
Pages: 810-815

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Abstract

QT interval prolongation, a risk factor for arrhythmias, may be associated with genetic variants in genes governing cardiac repolarization. Long QT syndrome type 2 (LQT2) is caused by mutations in the human ether-a-go‑go-related gene (hERG). This gene encodes a voltage-gated potassium channel comprised of 4 subunits, and the formation of functional channels requires the proper assembly of these 4 subunits. In the present study, we investigated the role of the LQT2 mutation, Q738X, which causes truncation of the C-terminus of hERG channels, in the assembly and function of hERG channels. When expressed in HEK293 cells, Q738X did not generate an hERG current. The co-expression of Q738X with wild-type (WT)-hERG did not cause the dominant-negative suppression of the WT-hERG current. Western blot analysis and confocal microscopy revealed that the Q738X mutation caused defective trafficking of hERG channel proteins. Co-immunoprecipitation demonstrated that Q738X did not exhibit dominant-negative effects due to the failure of the mutant and WT subunits to co-assemble. In conclusion, the functional loss caused by the Q738X mutation in hERG K+ channels may be attributed to the disruption of tetrameric assembly.

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1	Priori SG, Barhanin J, Hauer RN, Haverkamp W, Jongsma HJ, Kleber AG, McKenna WJ, Roden DM, Rudy Y, Schwartz K, Schwartz PJ, Towbin JA and Wilde AM: Genetic and molecular basis of cardiac arrhythmias: impact on clinical management parts I and II. Circulation. 99:518–528. 1999. View Article : Google Scholar : PubMed/NCBI
2	Craft TM: Torsade de pointes after astemizole overdose. Br Med J (Clin Res Ed). 292:6601986. View Article : Google Scholar : PubMed/NCBI
3	Mathews DR, McNutt B, Okerholm R, Flicker M and McBride G: Torsades de pointes occurring in association with terfenadine use. JAMA. 266:2375–2376. 1991. View Article : Google Scholar : PubMed/NCBI
4	Anderson CL, Delisle BP, Anson BD, Kilby JA, Will ML, Tester DJ, Gong Q, Zhou Z, Ackerman MJ and January CT: Most LQT2 mutations reduce Kv11.1 (hERG) current by a class 2 (trafficking-deficient) mechanism. Circulation. 113:365–373. 2006. View Article : Google Scholar : PubMed/NCBI
5	Gong Q, Keeney DR, Robinson JC and Zhou Z: Defective assembly and trafficking of mutant HERG channels with C-terminal truncations in long QT syndrome. J Mol Cell Cardiol. 37:1225–1233. 2004.PubMed/NCBI
6	Perrin MJ, Subbiah RN, Vandenberg JI and Hill AP: Human ether-a-go-go related gene (hERG) K⁺ channels: function and dysfunction. Prog Biophys Mol Biol. 98:137–148. 2008.
7	Yasuda S, Hiramatsu S, Odashiro K, Maruyama T, Tsuji K and Horie M: A family of hereditary long QT syndrome caused by Q738X HERG mutation. Int J Cardiol. 144:69–72. 2010. View Article : Google Scholar : PubMed/NCBI
8	Guo J, Han SN, Liu JX, Zhang XM, Hu ZS, Shi J, Zhang LR, Zhao ZZ and Zhang Z: The action of a novel fluoroquinolone antibiotic agent antofloxacin hydrochloride on human-ether-a-go-go-related gene potassium channel. Basic Clin Pharmacol Toxicol. 107:643–649. 2010. View Article : Google Scholar : PubMed/NCBI
9	Han S, Zhang Y, Chen Q, Duan Y, Zheng T, Hu X, Zhang Z and Zhang L: Fluconazole inhibits hERG K⁺ channel by direct block and disruption of protein trafficking. Eur J Pharmacol. 650:138–144. 2011.PubMed/NCBI
10	Takemasa H, Nagatomo T, Abe H, Kawakami K, Igarashi T, Tsurugi T, Kabashima N, Tamura M, Okazaki M, Delisle BP, January CT and Otsuji Y: Coexistence of hERG current block and disruption of protein trafficking in ketoconazole-induced long QT syndrome. Br J Pharmacol. 153:439–447. 2008. View Article : Google Scholar : PubMed/NCBI
11	Paulussen A, Yang P, Pangalos M, Verhasselt P, Marrannes R, Verfaille C, Vandenberk I, Crabbe R, Konings F, Luyten W and Armstrong M: Analysis of the human KCNH2(HERG) gene: identification and characterization of a novel mutation Y667X associated with long QT syndrome and a non-pathological 9 bp insertion. Hum Mutat. 15:483–487. 2000. View Article : Google Scholar : PubMed/NCBI
12	Aydar E and Palmer C: Functional characterization of the C-terminus of the human ether-a-go-go-related gene K⁺ channel (HERG). J Physiol. 534:1–14. 2001. View Article : Google Scholar : PubMed/NCBI
13	Johnson WH Jr, Yang P, Yang T, Lau YR, Mostella BA, Wolff DJ, Roden DM and Benson DW: Clinical, genetic, and biophysical characterization of a homozygous HERG mutation causing severe neonatal long QT syndrome. Pediatr Res. 53:744–748. 2003. View Article : Google Scholar : PubMed/NCBI
14	Keating MT and Sanguinetti MC: Molecular genetic insights into cardiovascular disease. Science. 272:681–685. 1996. View Article : Google Scholar : PubMed/NCBI
15	Tseng GN: I_Kr: the hERG channel. J Mol Cell Cardiol. 33:835–849. 2001.
16	Jenke M, Sanchez A, Monje F, Stuhmer W, Weseloh RM and Pardo LA: C-terminal domains implicated in the functional surface expression of potassium channels. EMBO J. 22:395–403. 2003. View Article : Google Scholar : PubMed/NCBI
17	Ficker E, Thomas D, Viswanathan PC, Dennis AT, Priori SG, Napolitano C, Memmi M, Wible BA, Kaufman ES, Iyengar S, Schwartz PJ, Rudy Y and Brown AM: Novel characteristics of a misprocessed mutant HERG channel linked to hereditary long QT syndrome. Am J Physiol Heart Circ Physiol. 279:H1748–H1756. 2000.PubMed/NCBI
18	Yao Y, Teng S, Li N, Zhang Y, Boyden PA and Pu J: Aminoglycoside antibiotics restore functional expression of truncated HERG channels produced by nonsense mutations. Heart Rhythm. 6:553–560. 2009. View Article : Google Scholar : PubMed/NCBI
19	Akhavan A, Atanasiu R, Noguchi T, Han W, Holder N and Shrier A: Identification of the cyclic-nucleotide-binding domain as a conserved determinant of ion-channel cell-surface localization. J Cell Sci. 118:2803–2812. 2005. View Article : Google Scholar : PubMed/NCBI
20	Lees-Miller JP, Duan Y, Teng GQ, Thorstad K and Duff HJ: Novel gain-of-function mechanism in K⁺ channel-related long-QT syndrome: altered gating and selectivity in the HERG1 N629D mutant. Circ Res. 86:507–513. 2000.