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Targeting of Kv7.5 (KCNQ5)/KCNE channels to surface microdomains of cell membranes

Authors

  • Meritxell Roura-Ferrer MD,

    1. Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
    2. Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas–Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Leioa, Spain
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  • Laura Solé MSc,

    1. Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
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  • Anna Oliveras MSc,

    1. Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
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  • Alvaro Villarroel PhD,

    1. Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas–Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Leioa, Spain
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  • Núria Comes PhD,

    1. Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
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  • Antonio Felipe PhD

    Corresponding author
    1. Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
    • Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
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Abstract

Background: Kv7.5 (KCNQ5) channels conduct M-type potassium currents in the brain, are expressed in skeletal muscle, and contribute to vascular muscle tone. Methods: We coexpressed Kv7.5 and KCNE1–3 peptides in HEK293 cells and then analyzed their association using electrophysiology and co-immunoprecipitation, assessed localization using confocal microscopy, examined targeting of the oligomeric channels to cholesterol-rich membrane surface microdomains using lipid raft isolation, and evaluated their membrane dynamics using fluorescence recovery after photobleaching (FRAP). Results: Kv7.5 forms oligomeric channels specifically with KCNE1 and KCNE3. The expression of Kv7.5 targeted to cholesterol-rich membrane surface microdomains was very low. Oligomeric Kv7.5/KCNE1 and Kv7.5/KCNE3 channels did not localize to lipid rafts. However, Kv7.5 association impaired KCNE3 expression in lipid raft microdomains. Conclusions: Our results indicate that Kv7.5 contributes to the spatial regulation of KCNE3. This new scenario could greatly assist in determining the physiological relevance of putative KCNE3 interactions in nerve and muscle. Muscle Nerve 45: 48–54, 2012

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