Mitochondrial calcium ion transport

Divalent calcium ions (Ca2+) are transported from the cytosol into the mitochondrial matrix and back out of the matrix into the cytosol (reviewed in Santo-Domingo et al. 2010, De Stefani et al. 2016). In the matrix, Ca2+ binds and allosterically regulates pyruvate dehydrogenase, isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase, and possibly other enzymes. Matrix calcium is also observed to regulate release of caspase cofactors and calcium flux through channels on neighboring membranes, The pathway into the mitochondrion involves VDAC1, VDAC2, and VDAC3 in the outer membrane and the mitochondrial calcium uniporter (MCU) complex in the inner membrane. VDACs in the open conformation are anion channels. However in the closed conformation they transport Ca2+ from the cytosol to the intermembrane space. When calcium concentrations in the cytosol and intermembrane space are high, the MCU complex opens and transports Ca2+ from the intermembrane space to the mitochondrial matrix using the driving force of the membrane potential (reviewed in Drago et al. 2011, Marchi et al. 2014, De Stefani et al. 2015).

Summary from Reactome (R-HSA-8949215), read 2026-09-23.