Light-Regulated Transcription of a Mitochondrial-Targeted K+ Channel

Cells. 2020 Nov 19;9(11):2507. doi: 10.3390/cells9112507.


The inner membranes of mitochondria contain several types of K+ channels, which modulate the membrane potential of the organelle and contribute in this way to cytoprotection and the regulation of cell death. To better study the causal relationship between K+ channel activity and physiological changes, we developed an optogenetic platform for a light-triggered modulation of K+ conductance in mitochondria. By using the light-sensitive interaction between cryptochrome 2 and the regulatory protein CIB1, we can trigger the transcription of a small and highly selective K+ channel, which is in mammalian cells targeted into the inner membrane of mitochondria. After exposing cells to very low intensities (≤0.16 mW/mm2) of blue light, the channel protein is detectable as an accumulation of its green fluorescent protein (GFP) tag in the mitochondria less than 1 h after stimulation. This system allows for an in vivo monitoring of crucial physiological parameters of mitochondria, showing that the presence of an active K+ channel causes a substantial depolarization compatible with the effect of an uncoupler. Elevated K+ conductance also results in a decrease in the Ca2+ concentration in the mitochondria but has no impact on apoptosis.

Keywords: apoptosis; mitochondrial Ca2+ manipulation; mitochondrial K+ channel; optogenetic platform.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Membrane Potentials / physiology*
  • Mitochondria / metabolism*
  • Potassium Channels / metabolism*


  • Potassium Channels