RT info:eu-repo/semantics/article
T1 D242N, a KV7.1 LQTS mutation uncovers a key residue for IKs voltage dependence
A1 Moreno, Cristina
A1 Oliveras, Anna
A1 Bartolucci, Chiara
A1 Muñoz, Carmen
A1 de la Cruz, Alicia
A1 Peraza, Diego A.
A1 Gimeno, Juan R.
A1 Martín-Martínez, Mercedes
A1 Severi, Stefano
A1 Felipe, Antonio
A1 Lambiase, Pier D.
A1 Gonzalez, Teresa
A1 Valenzuela, Carmen
AB KV7.1 and KCNE1 co-assemble to give rise to the IKs current, one of the most important repolarizing currents of the cardiac action potential. Its relevance is underscored by the identification of >500 mutations in KV7.1 and, at least, 36 in KCNE1, that cause Long QT Syndrome (LQTS). The aim of this study was to characterize the biophysical and cellular consequences of the D242N KV7.1 mutation associated with the LQTS. The mutation is located in the S4 transmembrane segment, within the voltage sensor of the KV7.1 channel, disrupting the conserved charge balance of this region. Perforated patch-clamp experiments show that, unexpectedly, the mutation did not disrupt the voltage-dependent activation but it removed the inactivation and slowed the activation kinetics of D242N KV7.1 channels. Biotinylation of cell-surface protein and co-immunoprecipitation experiments revealed that neither plasma membrane targeting nor co-assembly between KV7.1 and KCNE1 was altered by the mutation. However, the association of D242N KV7.1 with KCNE1 strongly shifted the voltage dependence of activation to more depolarized potentials (+50mV), hindering IKs current at physiologically relevant membrane potentials. Both functional and computational analysis suggest that the clinical phenotype of the LQTS patients carrying the D242N mutation is due to impaired action potential adaptation to exercise and, in particular, to increase in heart rate. Moreover, our data identify D242 aminoacidic position as a potential residue involved in the KCNE1-mediated regulation of the voltage dependence of activation of the KV7.1 channel.
SN 0022-2828
YR 2017
FD 2017
LK https://uvadoc.uva.es/handle/10324/66032
UL https://uvadoc.uva.es/handle/10324/66032
LA spa
NO J Mol Cell Cardiol . 2017 Sep:110:61-69. doi: 10.1016/j.yjmcc.2017.07.009. Epub 2017 Jul 22.
DS UVaDOC
RD 23-may-2024