Ca2+ is taken up in energized mitochondria via the Ca2+ uniporter (CU). It is driven by the electrochemical gradient of Ca2+ across the inner mitochondrial membrane (IMM). It is also influenced by the kinetics of Ca2+ binding to the CU. CU plays a major role in mitochondrial function or dysfunction by regulating the dynamics of mitochondrial [Ca2+].
Dash, RK and Beard, DA. Analysis of Cardiac Mitochondrial Na+/Ca2+ Exchanger Kinetics with a Biophysical Model of Mitochondrial Ca2+ Handing Suggests a 3:1 Stoichiometry. J Physiol, 2008.