J 2014

Long-QT mutation p.K557E-Kv7.1: dominant-negative suppression of I-Ks, but preserved cAMP-dependent up-regulation

SPÄTJENS, Roel L.H.M.G., Markéta BÉBAROVÁ, Sandrine R.M. SEYEN, Viola LENTINK, Roselie J. JONGBLOED et. al.

Základní údaje

Originální název

Long-QT mutation p.K557E-Kv7.1: dominant-negative suppression of I-Ks, but preserved cAMP-dependent up-regulation

Autoři

SPÄTJENS, Roel L.H.M.G. (528 Nizozemské království), Markéta BÉBAROVÁ (203 Česká republika, garant, domácí), Sandrine R.M. SEYEN (528 Nizozemské království), Viola LENTINK (528 Nizozemské království), Roselie J. JONGBLOED (528 Nizozemské království), Yvonne H.J.M. ARENS (528 Nizozemské království), Jordi HEIJMAN (276 Německo) a Paul G.A. VOLDERS (528 Nizozemské království)

Vydání

Cardiovascular Research, Netherlands, Elsevier Science B.V. 2014, 0008-6363

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

30201 Cardiac and Cardiovascular systems

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 5.940

Kód RIV

RIV/00216224:14110/14:00076953

Organizační jednotka

Lékařská fakulta

UT WoS

000343317000022

Klíčová slova anglicky

Long-QT syndrome type 1; I-Ks; Potassium channel; Adrenergic regulation; KCNQ1

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 28. 11. 2014 13:53, Ing. Mgr. Věra Pospíšilíková

Anotace

V originále

Aims Mutations in KCNQ1, encoding for Kv7.1, the alpha-subunit of the I-Ks channel, cause long-QT syndrome type 1, potentially predisposing patients to ventricular tachyarrhythmias and sudden cardiac death, in particular, during elevated sympathetic tone. Here, we aim at characterizing the p.Lys557Glu (K557E) Kv7.1 mutation, identified in a Dutch kindred, at baseline and during (mimicked) increased adrenergic tone. Methods and results K557E carriers had moderate QTc prolongation that augmented significantly during exercise. I-Ks characteristics were determined after co-expressing Kv7.1-wild-type (WT) and/or K557E with minK and Yotiao in Chinese hamster ovary cells. K557E caused I-Ks loss of function with slowing of the activation kinetics, acceleration of deactivation kinetics, and a rightward shift of voltage-dependent activation. Together, these contributed to a dominant-negative reduction in I-Ks density. Confocal microscopy and western blot indicated that trafficking of K557E channels was not impaired. Stimulation of WT I-Ks by 3'-5'-cyclic adenosine monophosphate (cAMP) generated strong current up-regulation that was preserved for K557E in both hetero- and homozygosis. Accumulation of I-Ks at fast rates occurred both in WT and in K557E, but was blunted in the latter. In a computational model, K557E showed a loss of action potential shortening during beta-adrenergic stimulation, in accordance with the lack of QT shortening during exercise in patients. Conclusion K557E causes I-Ks loss of function with reduced fast rate-dependent current accumulation. cAMP-dependent stimulation of mutant I-Ks is preserved, but incapable of fully compensating for the baseline current reduction, explaining the long QT intervals at baseline and the abnormal QT accommodation during exercise in affected patients.