title: Targeting of Kv7.5 (KCNQ5)/KCNE channels to surface microdomains of cell membranes.
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.
authors.affiliation: Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Roura-Ferrer
authors.forename: Laura
authors.initials: L
authors.lastname: Solé
authors.forename: Anna
authors.initials: A
authors.lastname: Oliveras
authors.forename: Alvaro
authors.initials: A
authors.lastname: Villarroel
authors.forename: Núria
authors.initials: N
authors.lastname: Comes
authors.forename: Antonio
authors.initials: A
authors.lastname: Felipe
mesh_terms: D002461:Cell Line, Transformed; D004558:Electric Stimulation; D036681:Fluorescence Recovery After Photobleaching; D006801:Humans; D047468:Immunoprecipitation; D051656:KCNQ Potassium Channels / Q000235:genetics / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D018408:Patch-Clamp Techniques; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D014162:Transfection / Q000379:methods
chemical_list: D051656:KCNQ Potassium Channels; C412231:KCNQ5 protein, human; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits