Voltage-dependent inwardly rectifying potassium conductance in the outer membrane of neuronal mitochondria

J Biol Chem. 2010 Aug 27;285(35):27411-27417. doi: 10.1074/jbc.M110.131243. Epub 2010 Jun 15.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Membrane Potential, Mitochondrial / physiology*
  • Mice
  • Mice, Transgenic
  • Mitochondrial Membranes / metabolism*
  • Neurons / metabolism*
  • Potassium / metabolism*
  • Potassium Channels, Inwardly Rectifying / genetics
  • Potassium Channels, Inwardly Rectifying / metabolism*


  • Potassium Channels, Inwardly Rectifying
  • Potassium