Single channel recording of a mitochondrial calcium uniporter

Biochem Biophys Res Commun. 2018 Jan 29;496(1):127-132. doi: 10.1016/j.bbrc.2018.01.010. Epub 2018 Jan 4.

Abstract

Mitochondrial calcium uniporter (MCU) is the pore-forming subunit of the entire uniporter complex and plays an important role in mitochondrial calcium uptake. However, the single channel recording of MCU remains controversial. Here, we expressed and purified different MCU proteins and then reconstituted them into planar lipid bilayers for single channel recording. We showed that MCU alone from Pyronema omphalodes (pMCU) is active with prominent single channel Ca2+ currents. In sharp contrast, MCU alone from Homo sapiens (hMCU) is inactive. The essential MCU regulator (EMRE) activates hMCU, and therefore, the complex (hMCU-hEMRE) shows prominent single channel Ca2+ currents. These single channel currents are sensitive to the specific MCU inhibitor Ruthenium Red. Our results clearly demonstrate that active MCU can conduct large amounts of calcium into the mitochondria.

Keywords: Calcium signaling; MCU; Mitochondrial calcium uniporter; Mitochondrial calcium uptake; Single channel recording.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / chemistry*
  • Calcium Channels / chemistry*
  • Calcium Signaling*
  • Humans
  • Ion Channel Gating*
  • Lipid Bilayers / chemistry*
  • Membrane Potential, Mitochondrial*
  • Mitochondrial Membranes / chemistry*
  • Species Specificity

Substances

  • Calcium Channels
  • Lipid Bilayers
  • mitochondrial calcium uniporter
  • Calcium