Sandbox Reserved 1626: Difference between revisions
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Under resting conditions, the calcium concentration in the mitochondria is about the same as in the [https://en.wikipedia.org/wiki/Cytoplasm cytoplasm], but when stimulated, it can increase calcium concentration 10-20-fold.<ref name="Giorgi">PMID:30143745</ref> Mitochondria-associated ER membranes ([https://en.wikipedia.org/wiki/Mitochondria_associated_membranes MAMs]) exist between mitochondria and the [https://en.wikipedia.org/wiki/Endoplasmic_reticulum endoplasmic reticulum], the two largest cellular stores of calcium, to allow for efficient transport of calcium ions.<ref name="Wang">PMID:28882140</ref> The transfer of electrons through respiratory complexes I-IV produces the energy to pump [https://en.wikipedia.org/wiki/Hydrogen_ion hydrogen ions] into the intermembrane space (IMS) and create the proton [https://en.wikipedia.org/wiki/Electrochemical_gradient electrochemical gradient] potential.<ref name="Giorgi"/> This negative electrochemical potential is the driving force that moves positively charged calcium ions into the mitochondrial matrix.<ref name="Giorgi"/> | Under resting conditions, the calcium concentration in the mitochondria is about the same as in the [https://en.wikipedia.org/wiki/Cytoplasm cytoplasm], but when stimulated, it can increase calcium concentration 10-20-fold.<ref name="Giorgi">PMID:30143745</ref> Mitochondria-associated ER membranes ([https://en.wikipedia.org/wiki/Mitochondria_associated_membranes MAMs]) exist between mitochondria and the [https://en.wikipedia.org/wiki/Endoplasmic_reticulum endoplasmic reticulum], the two largest cellular stores of calcium, to allow for efficient transport of calcium ions.<ref name="Wang">PMID:28882140</ref> The transfer of electrons through respiratory complexes I-IV produces the energy to pump [https://en.wikipedia.org/wiki/Hydrogen_ion hydrogen ions] into the intermembrane space (IMS) and create the proton [https://en.wikipedia.org/wiki/Electrochemical_gradient electrochemical gradient] potential.<ref name="Giorgi"/> This negative electrochemical potential is the driving force that moves positively charged calcium ions into the mitochondrial matrix.<ref name="Giorgi"/> | ||
Regulation of the uptake and efflux of calcium is important to increase calcium levels enough to activate certain enzymes, but also avoid calcium overload and apoptosis.<ref name="Wang"/> Mitochondrial calcium increases ATP production by activating pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and isocitrate dehydrogenase in the Krebs cycle.<ref name="Wang"/> Therefore, deficiency of MCU leads to decrease of enzyme activity and of | Regulation of the uptake and efflux of calcium is important to increase calcium levels enough to activate certain enzymes, but also avoid calcium overload and [https://en.wikipedia.org/wiki/Apoptosis apoptosis].<ref name="Wang"/> Mitochondrial calcium increases [http://proteopedia.org/wiki/index.php/ATP ATP] production by activating [http://proteopedia.org/wiki/index.php/Pyruvate_dehydrogenase pyruvate dehydrogenase], [https://en.wikipedia.org/wiki/Oxoglutarate_dehydrogenase_complex α-ketoglutarate dehydrogenase], and [http://proteopedia.org/wiki/index.php/Isocitrate_dehydrogenase isocitrate dehydrogenase] in the [https://en.wikipedia.org/wiki/Citric_acid_cycle Krebs cycle].<ref name="Wang"/> Therefore, deficiency of MCU leads to decrease of enzyme activity and of [https://en.wikipedia.org/wiki/Oxidative_phosphorylation ocidative phosphorylation]. | ||
==Structure== | ==Structure== | ||
