title: Voltage-dependent inwardly rectifying potassium conductance in the outer membrane of neuronal mitochondria.
abstract: Potassium fluxes integrate mitochondria into cellular activities, controlling their volume homeostasis and structural integrity in many pathophysiological mechanisms. The outer mitochondrial membrane (OMM) is thought to play a passive role in this process because K(+) is believed to equilibrate freely between the cytosol and mitochondrial intermembrane space. By patch clamping mitochondria isolated from the central nervous systems of adult mitoCFP transgenic mice, we discovered the existence of I(OMMKi), a novel voltage-dependent inwardly rectifying K(+) conductance located in the OMM. I(OMMKi) is regulated by osmolarity, potentiated by cAMP, and activated at physiological negative potentials, allowing K(+) to enter the mitochondrial intermembrane space in a controlled regulated fashion. The identification of I(OMMKi) in the OMM supports the notion that a membrane potential could exist across this membrane in vivo and suggests that the OMM possesses regulated pathways for K(+) uptake.
authors.affiliation: Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fieni
authors.affiliation: Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
authors.forename: Anjum
authors.initials: A
authors.lastname: Parkar
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
authors.forename: Thomas
authors.initials: T
authors.lastname: Misgeld
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
authors.forename: Martin
authors.initials: M
authors.lastname: Kerschensteiner
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
authors.forename: Jeff W
authors.initials: JW
authors.lastname: Lichtman
authors.affiliation: Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
authors.forename: Piera
authors.initials: P
authors.lastname: Pasinelli
authors.affiliation: Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107. Electronic address: davide.trotti@jefferson.edu.
authors.forename: Davide
authors.initials: D
authors.lastname: Trotti
mesh_terms: D000818:Animals; D053078:Membrane Potential, Mitochondrial / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D051336:Mitochondrial Membranes / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*
chemical_list: D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium