TY  - JOUR
A1  - Girmatsion, Zenawit
A1  - Biliczki, Peter
A1  - Takac, Ina
A1  - Schwerthelm, Christin
A1  - Hohnloser, Stefan H.
A1  - Ehrlich, Joachim
T1  - N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes
T2  - PLoS One
N2  - Background and Objective: The slow delayed rectifier current (IKs) is important for cardiac action potential termination. The underlying channel is composed of Kv7.1 α-subunits and KCNE1 β-subunits. While most evidence suggests a role of KCNE1 transmembrane domain and C-terminus for the interaction, the N-terminal KCNE1 polymorphism 38G is associated with reduced IKs and atrial fibrillation (a human arrhythmia). Structure-function relationship of the KCNE1 N-terminus for IKs modulation is poorly understood and was subject of this study.

Methods: We studied N-terminal KCNE1 constructs disrupting structurally important positively charged amino-acids (arginines) at positions 32, 33, 36 as well as KCNE1 constructs that modify position 38 including an N-terminal truncation mutation. Experimental procedures included molecular cloning, patch-clamp recording, protein biochemistry, real-time-PCR and confocal microscopy.

Results: All KCNE1 constructs physically interacted with Kv7.1. IKs resulting from co-expression of Kv7.1 with non-atrial fibrillation ‘38S’ was greater than with any other construct. Ionic currents resulting from co-transfection of a KCNE1 mutant with arginine substitutions (‘38G-3xA’) were comparable to currents evoked from cells transfected with an N-terminally truncated KCNE1-construct (‘Δ1-38’). Western-blots from plasma-membrane preparations and confocal images consistently showed a greater amount of Kv7.1 protein at the plasma-membrane in cells co-transfected with the non-atrial fibrillation KCNE1-38S than with any other construct.

Conclusions: The results of our study indicate that N-terminal arginines in positions 32, 33, 36 of KCNE1 are important for reconstitution of IKs. Furthermore, our results hint towards a role of these N-terminal amino-acids in membrane representation of the delayed rectifier channel complex.
Y1  - 2011
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/23731
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-237315
SN  - 1932-6203
VL  - 6
IS  - 11: e26967
SP  - 1
EP  - 9
PB  - PLoS
CY  - Lawrence, Kan.
ER  -