Voltage-dependent inwardly rectifying potassium conductance in the outer membrane of neuronal mitochondria.
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.
Fieni
Francesca
F
Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Parkar
Anjum
A
Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Misgeld
Thomas
T
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
Kerschensteiner
Martin
M
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
Lichtman
Jeff W
JW
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138.
Pasinelli
Piera
P
Department of Neuroscience, Weinberg Unit for ALS Research, and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Trotti
Davide
D
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.
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*
D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium