N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes.
BACKGROUND AND OBJECTIVE: The slow delayed rectifier current (I(Ks)) 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 interactio...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2011-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3208574?pdf=render |
| _version_ | 1828235076865884160 |
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| author | Zenawit Girmatsion Peter Biliczki Ina Takac Christin Schwerthelm Stefan H Hohnloser Joachim R Ehrlich |
| author_facet | Zenawit Girmatsion Peter Biliczki Ina Takac Christin Schwerthelm Stefan H Hohnloser Joachim R Ehrlich |
| author_sort | Zenawit Girmatsion |
| collection | DOAJ |
| description | BACKGROUND AND OBJECTIVE: The slow delayed rectifier current (I(Ks)) 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 I(Ks) and atrial fibrillation (a human arrhythmia). Structure-function relationship of the KCNE1 N-terminus for I(Ks) 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. I(Ks) 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 I(Ks). Furthermore, our results hint towards a role of these N-terminal amino-acids in membrane representation of the delayed rectifier channel complex. |
| first_indexed | 2024-04-12T20:07:34Z |
| format | Article |
| id | doaj.art-0cb8504e36894c69baa97e86dad4ea08 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-12T20:07:34Z |
| publishDate | 2011-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-0cb8504e36894c69baa97e86dad4ea082022-12-22T03:18:20ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-01611e2696710.1371/journal.pone.0026967N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes.Zenawit GirmatsionPeter BiliczkiIna TakacChristin SchwerthelmStefan H HohnloserJoachim R EhrlichBACKGROUND AND OBJECTIVE: The slow delayed rectifier current (I(Ks)) 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 I(Ks) and atrial fibrillation (a human arrhythmia). Structure-function relationship of the KCNE1 N-terminus for I(Ks) 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. I(Ks) 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 I(Ks). Furthermore, our results hint towards a role of these N-terminal amino-acids in membrane representation of the delayed rectifier channel complex.http://europepmc.org/articles/PMC3208574?pdf=render |
| spellingShingle | Zenawit Girmatsion Peter Biliczki Ina Takac Christin Schwerthelm Stefan H Hohnloser Joachim R Ehrlich N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. PLoS ONE |
| title | N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. |
| title_full | N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. |
| title_fullStr | N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. |
| title_full_unstemmed | N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. |
| title_short | N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes. |
| title_sort | n terminal arginines modulate plasma membrane localization of kv7 1 kcne1 channel complexes |
| url | http://europepmc.org/articles/PMC3208574?pdf=render |
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