ID 6870
File
Authors
Kondo, Takehito Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University
Hisatome, Ichiro Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science Researchers DB KAKEN
Yoshimura, Shouichi Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science
Mahati, Endang Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science
Notsu, Tomomi Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science
Li, Peili Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science Researchers DB KAKEN
Iizuka, Kazuhiko Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University Researchers DB
Kato, Masaru Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University Researchers DB KAKEN
Ogura, Kazuyoshi Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University Researchers DB
Miake, Junichiro Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University Researchers DB KAKEN
Aiba, Takeshi Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center
Shimizu, Wataru Division of Cardiology and Regenerative Medicine, Nippon Medical School
Kurata, Yasutaka Department of Physiology II, Kanazawa Medical University
Sakata, Shinji Department of Pediatrics, Faculty of Medicine, Tottori University Researchers DB
Nakasone, Naoe Department of Biological Regulation, Faculty of Medicine, Tottori University Researchers DB KAKEN
Ninomiya, Haruaki Department of Biological Regulation, Faculty of Medicine, Tottori University Researchers DB KAKEN
Nakai, Akira Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine
Higaki, Katsumi Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University Researchers DB KAKEN
Kawata, Yasushi Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University Researchers DB KAKEN
Shirayoshi, Yasuaki Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science Researchers DB KAKEN
Yoshida, Akio Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science
Yamamoto, Kazuhiro Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University Researchers DB KAKEN
Keywords
Long QT syndrome
Human ether-a-go-go-related gene
Heat shock factor
Abstract
Background:The human ether-a-go-go-related gene (HERG) encodes the α-subunit of rapidly activating delayed-rectifier potassium channels. Mutations in this gene cause long QT syndrome type 2 (LQT2). In most cases, mutations reduce the stability of the channel protein, which can be restored by heat shock (HS). Methods: We identified the novel mutant A78T-HERG in a patient with LQT2. The purpose of the current study was to characterize this mutant protein and test whether HS and heat shock factors (HSFs) could stabilize the mutant protein. A78T-HERG and wild-type HERG (WT-HERG) were expressed in HEK293 cells and analyzed by immunoblotting, immunoprecipitation, immunofluorescence, and whole-cell patch clamping. Results: When expressed in HEK293 cells, WT-HERG gave rise to immature and mature forms of the protein at 135 and 155 kDa, respectively. A78T-HERG gave rise only to the immature form, which was heavily ubiquitinated. The proteasome inhibitor MG132 increased the expression of immature A78T-HERG and increased both the immature and mature forms of WT-HERG. WT-HERG, but not A78T-HERG, was expressed on the plasma membrane. In whole-cell patch clamping experiments, depolarizing pulses evoked E4031-sensitive HERG channel currents in cells transfected with WT-HERG, but not in cells transfected with A78T-HERG. The A78V mutant, but not A78G mutant, remained in the immature form similarly to A78T. Maturation of the A78T-HERG protein was facilitated by HS, expression of HSF-1, or exposure to geranyl geranyl acetone. Conclusions: A78T-HERG was characterized by protein instability and reduced expression on the plasma membrane. The stability of the mutant was partially restored by HSF-1, indicating that HSF-1 is a target for the treatment for LQT2 caused by the A78T mutation in HERG.
Publisher
Elsevier B.V.
Content Type
Journal Article
Link
ISSN
18804276
Journal Title
Journal of Arrhythmia
Current Journal Title
Journal of Arrhythmia
Volume
32
Issue
5
Start Page
433
End Page
440
Published Date
2016-10-31
Publisher-DOI
Text Version
Publisher
Rights
© 2015 Japanese Heart Rhythm Society. Published by Elsevier B.V. http://creativecommons.org/licenses/by-nc-nd/4.0/
Citation
Kondo, Takehito. Hisatome, Ichiro. Yoshimura, Shouichi. et al. Characterization of the novel mutant A78T-HERG from a long QT syndrome type 2 patient: Instability of the mutant protein and stabilization by heat shock factor 1. Journal of Arrhythmia. 32. 433-440. 2016-10-31.
Department
Faculty of Medicine/Graduate School of Medical Sciences/University Hospital
Language
English
pii
S1880-4276(15)00143-X