title: Electrophysiological study of V535M hERG mutation of LQT2.
abstract: This study examined the current changes of human ether-a-go-go-related gene (hERG) mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identified and site-directed mutagenesis was performed to induce the mutation in wild-type (WT) hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A>G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of -40 mV after depolarizing at +50 mV, tail current densities were 83.35±7.06 pA/pF in WT and 50.38±7.74 pA/pF in V535M respectively (n=20, P<0.01). Gating kinetics of hERG revealed that V                         (1/2) of steady-state inactivation shifted to negative potential in the mutant (V                         (1/2,V535M): -61.81±1.7 mV vs. V                         (1/2, WT): -43.1±0.71 mV). The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.|Department of Transfusion Medicine, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Shao
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Mohan
authors.initials: M
authors.lastname: Liu
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Lan
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Min
authors.initials: M
authors.lastname: Lin
authors.affiliation: Institute of Geriatric Cardiology of Chinese PLA General Hospital, Beijing, 100853, China. liyangbsh@163.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D008133:Long QT Syndrome / Q000151:congenital / Q000235:genetics* / Q000503:physiopathology*; D008297:Male; D008564:Membrane Potentials; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010375:Pedigree; D013575:Syncope / Q000209:etiology; D014162:Transfection
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human