The Na+/Ca2+ Exchanger (NCE) is responsible for the extrution of Ca2+ in exchange of Na+ from respiring and non-respiring mitochondria. Thus, the NCE plays a major role in the regulation 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