Newly developed Mg2+-selective fluorescent probe enables visualization of Mg2+ dynamics in mitochondria

PLoS One. 2011;6(8):e23684. doi: 10.1371/journal.pone.0023684. Epub 2011 Aug 16.


Mg(2+) plays important roles in numerous cellular functions. Mitochondria take part in intracellular Mg(2+) regulation and the Mg(2+) concentration in mitochondria affects the synthesis of ATP. However, there are few methods to observe Mg(2+) in mitochondria in intact cells. Here, we have developed a novel Mg(2+)-selective fluorescent probe, KMG-301, that is functional in mitochondria. This probe changes its fluorescence properties solely depending on the Mg(2+) concentration in mitochondria under physiologically normal conditions. Simultaneous measurements using this probe together with a probe for cytosolic Mg(2+), KMG-104, enabled us to compare the dynamics of Mg(2+) in the cytosol and in mitochondria. With this method, carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP)-induced Mg(2+) mobilization from mitochondria to the cytosol was visualized. Although a FCCP-induced decrease in the Mg(2+) concentration in mitochondria and an increase in the cytosol were observed both in differentiated PC12 cells and in hippocampal neurons, the time-courses of concentration changes varied with cell type. Moreover, the relationship between mitochondrial Mg(2+) and Parkinson's disease was analyzed in a cellular model of Parkinson's disease by using the 1-methyl-4-phenylpyridinium ion (MPP(+)). A gradual decrease in the Mg(2+) concentration in mitochondria was observed in response to MPP(+) in differentiated PC12 cells. These results indicate that KMG-301 is useful for investigating Mg(2+) dynamics in mitochondria. All animal procedures to obtain neurons from Wistar rats were approved by the ethical committee of Keio University (permit number is 09106-(1)).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Methyl-4-phenylpyridinium / pharmacology
  • Animals
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / pharmacology
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism
  • Cells, Cultured
  • Cytosol / chemistry
  • Cytosol / metabolism
  • Fluorescent Dyes / chemical synthesis
  • Fluorescent Dyes / chemistry*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Hippocampus / cytology
  • Ion Transport / drug effects
  • Magnesium / chemistry
  • Magnesium / metabolism*
  • Microscopy, Confocal
  • Mitochondria / chemistry
  • Mitochondria / drug effects
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Molecular Dynamics Simulation*
  • Molecular Structure
  • Neurons / chemistry
  • Neurons / drug effects
  • Neurons / metabolism
  • PC12 Cells
  • Proton Ionophores / pharmacology
  • RNA, Small Interfering / genetics
  • Rats
  • Rats, Wistar
  • Spectrometry, Fluorescence
  • Transfection


  • Cation Transport Proteins
  • Fluorescent Dyes
  • MRS2 protein, rat
  • Mitochondrial Proteins
  • Proton Ionophores
  • RNA, Small Interfering
  • Green Fluorescent Proteins
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
  • Magnesium
  • 1-Methyl-4-phenylpyridinium