Mitochondrial Ca2+ transport and the role of intramitochondrial Ca2+ in the regulation of energy metabolism.
The mitochondrial inner membrane of all mammalian tissues, including brain tissues, has specific active transport systems for the uptake and egress of Ca2+. The primary role of this transport system is to relay changes in cytosolic [Ca2+], which stimulates energy-requiring processes in the cytosol (e.g. secretion), into the mitochondrial matrix where it stimulates several key steps in energy production. Thus using the same second-messenger molecule, the latter events allow energetic homeostasis to be maintained under conditions of cell stimulation. This appears to be brought about by a co-ordinated enhancement of steps throughout the pathways of oxidative phosphorylation, including substrate supply to the respiratory chain by dehydrogenase activation, activation of the respiratory chain itself by a mechanism which appears to involve changes in the matrix volume, and also possibly activation of the ATP synthetase where the release of a specific inhibitory subunit has been proposed.
McCormack
J G
JG
Department of Pharmacology, Syntex Research Centre, Heriot-Watt University Research Park, Edinburgh, Scotland.
Denton
R M
RM
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D004734:Energy Metabolism; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*
D002118:Calcium