title: A large-conductance calcium-regulated K+ channel in human dermal fibroblast mitochondria.
abstract: Potassium channels have been found in the inner mitochondrial membrane of various cells. These channels regulate the mitochondrial membrane potential, respiration and production of reactive oxygen species. In the present study, we identified the activity of a mitochondrial large-conductance Ca2+-regulated potassium channel (mitoBKCachannel) in mitoplasts isolated from a primary human dermal fibroblast cell line. A potassium selective current was recorded with a mean conductance of 280 ± 2 pS in a symmetrical 150 mM KCl solution. The mitoBKCachannel was activated by the Ca2+and by potassium channel opener NS1619. The channel activity was irreversibly inhibited by paxilline, a selective inhibitor of the BKCachannels. In isolated fibroblast mitochondria NS1619 depolarized the mitochondrial membrane potential, stimulated nonphosphorylating respiration and decreased superoxide formation. Additionally, the α- and β-subunits (predominantly the β3-form) of the BKCachannels were identified in fibroblast mitochondria. Our findings indicate, for the first time, the presence of a large-conductance Ca2+-regulated potassium channel in the inner mitochondrial membrane of human dermal fibroblasts.
authors.affiliation: Laboratory of Bioenergetics, Adam Mickiewicz University, Poznan, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kicinska
authors.affiliation: Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., Warsaw 02-093, Poland.
authors.forename: Bartlomiej
authors.initials: B
authors.lastname: Augustynek
authors.affiliation: Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., Warsaw 02-093, Poland.
authors.forename: Bogusz
authors.initials: B
authors.lastname: Kulawiak
authors.affiliation: Laboratory of Bioenergetics, Adam Mickiewicz University, Poznan, Poland.
authors.forename: Wieslawa
authors.initials: W
authors.lastname: Jarmuszkiewicz
authors.affiliation: Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., Warsaw 02-093, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Szewczyk
authors.affiliation: Department of Biophysics, Warsaw University of Life Sciences (SGGW), Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Bednarczyk
mesh_terms: D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D012867:Skin / Q000166:cytology*; D013481:Superoxides / Q000378:metabolism
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels; D013481:Superoxides
keywords: bioenergetics; dermal fibroblasts; electrophysiology; mitochondria; potassium channel