The regulatory role of mitochondria in capacitative calcium entry.
Capacitative regulation of calcium entry is a major mechanism of Ca2+ influx into electrically non-excitable cells, but it also operates in some excitable ones. It participates in the refilling of intracellular calcium stores and in the generation of Ca2+ signals in excited cells. The mechanism which couples depletion of intracellular calcium stores located in the endoplasmic reticulum with opening of store-operated calcium channels in the plasma membrane is not clearly understood. Mitochondria located in close proximity to Ca2+ channels are exposed to high Ca2+ concentration, and therefore, they are able to accumulate this cation effectively. This decreases local Ca2+ concentration and thereby affects calcium-dependent processes, such as depletion and refilling of the intracellular calcium stores and opening of the store-operated channels. Finally, mitochondria modulate the intensity and the duration of calcium signals induced by extracellular stimuli. Ca2+ uptake by mitochondria requires these organelles to be in the energized state. On the other hand, Ca2+ flux into mitochondria stimulates energy metabolism. To sum up, mitochondria couple cellular metabolism with calcium homeostasis and signaling.
Duszyński
Jerzy
J
Nencki Institute of Experimental Biology, 3 Pasteur Str., 02-093 Warsaw, Poland.
Kozieł
Rafał
R
Brutkowski
Wojciech
W
Szczepanowska
Joanna
J
Zabłocki
Krzysztof
K
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology; D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000502:physiology*; D015398:Signal Transduction
D015220:Calcium Channels; D002118:Calcium