Calcium uptake mechanisms of mitochondria

Biochim Biophys Acta. Jun-Jul 2010;1797(6-7):907-12. doi: 10.1016/j.bbabio.2010.01.005. Epub 2010 Jan 14.


The ability of mitochondria to capture Ca2+ ions has important functional implications for cells, because mitochondria shape cellular Ca2+ signals by acting as a Ca2+ buffer and respond to Ca2+ elevations either by increasing the cell energy supply or by triggering the cell death program of apoptosis. A mitochondrial Ca2+ channel known as the uniporter drives the rapid and massive entry of Ca2+ ions into mitochondria. The uniporter operates at high, micromolar cytosolic Ca2+ concentrations that are only reached transiently in cells, near Ca2+ release channels. Mitochondria can also take up Ca2+ at low, nanomolar concentrations, but this high affinity mode of Ca2+ uptake is not well characterized. Recently, leucine-zipper-EF hand-containing transmembrane region (Letm1) was proposed to be an electrogenic 1:1 mitochondrial Ca2+/H+ antiporter that drives the uptake of Ca2+ into mitochondria at nanomolar cytosolic Ca2+ concentrations. In this article, we will review the properties of the Ca2+ import systems of mitochondria and discuss how Ca2+ uptake via an electrogenic 1:1 Ca2+/H+ antiport challenges our current thinking of the mitochondrial Ca2+ uptake mechanism.

Publication types

  • Review

MeSH terms

  • Animals
  • Antiporters / metabolism
  • Calcium / metabolism*
  • Calcium Channels / metabolism
  • Calcium Signaling
  • Calcium-Binding Proteins / metabolism
  • Cation Transport Proteins / metabolism
  • Humans
  • Ion Transport
  • Membrane Proteins / metabolism
  • Mitochondria / metabolism*
  • Models, Biological


  • Antiporters
  • Calcium Channels
  • Calcium-Binding Proteins
  • Cation Transport Proteins
  • LETM1 protein, human
  • Membrane Proteins
  • calcium-hydrogen antiporters
  • mitochondrial calcium uniporter
  • Calcium