Sandbox Reserved 1626: Difference between revisions
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[[Image:Ruthenium_Red.jpg|300 px|right|thumb|'''Fig. 2''' Structure of Ruthenium Red]] | [[Image:Ruthenium_Red.jpg|300 px|right|thumb|'''Fig. 2''' Structure of Ruthenium Red]] | ||
The mitochondrial calcium uniporter (MCU) complex is the main source of entry for calcium ions into the mitochondrial matrix from the intermembrane space. MCU channels exist in most eukaryotic life, but activity is regulated differently in each clade.<ref name="Baradaran">PMID:29995857</ref> The precise identity of the MCU wasn't discovered until 2011 and was discovered using a combination of NMR spectroscopy, cryo-electron microscopy, and x-ray crystallography.<ref name="Woods">PMID:31869674</ref> Identification of the structure was difficult because it has no apparent sequence similarity to other ion channels.<ref name="Baradaran"/> However, like other ion channels, it is incredibly selective and efficient. The MCU has the ability to only allow calcium ions into the mitochondrial matrix at a rate of 5,000,000 ions per second even though potassium ions are over 100,000 times more abundant in the intermembrane space.<ref name="Baradaran"/> | The mitochondrial calcium uniporter (MCU) complex is the main source of entry for [https://en.wikipedia.org/wiki/Calcium calcium] ions into the mitochondrial matrix from the intermembrane space. MCU channels exist in most eukaryotic life, but activity is regulated differently in each clade.<ref name="Baradaran">PMID:29995857</ref> The precise identity of the MCU wasn't discovered until 2011 and was discovered using a combination of NMR spectroscopy, cryo-electron microscopy, and x-ray crystallography.<ref name="Woods">PMID:31869674</ref> Identification of the structure was difficult because it has no apparent sequence similarity to other ion channels.<ref name="Baradaran"/> However, like other ion channels, it is incredibly selective and efficient. The MCU has the ability to only allow calcium ions into the mitochondrial matrix at a rate of 5,000,000 ions per second even though potassium ions are over 100,000 times more abundant in the intermembrane space.<ref name="Baradaran"/> | ||
Under resting conditions, the calcium concentration in the mitochondria is about the same as in the cytoplasm, but when stimulated, it can increase calcium concentration 10-20-fold.<ref name="Giorgi">PMID:30143745</ref> Mitochondria-associated ER membranes (MAMs) exist between mitochondria and the 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 hydrogen ions into the intermembrane space (IMS) and create the proton 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 cytoplasm, but when stimulated, it can increase calcium concentration 10-20-fold.<ref name="Giorgi">PMID:30143745</ref> Mitochondria-associated ER membranes (MAMs) exist between mitochondria and the 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 hydrogen ions into the intermembrane space (IMS) and create the proton 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"/> | ||
