Regulatory mechanisms of mitochondrial calcium uptake by the calcium uniporter complex

Mitochondria play an important role in energy conversion as well as in intracellular calcium (Ca(2+)) storage. Ca(2+) uptake from the cytosol to the mitochondria is mediated by the calcium uniporter, which functions as a Ca(2+) ion channel. However, the molecular composition of this uniporter has remained unclear until recently. The Ca(2+) ion channel consists of seven subunits. The yeast reconstitution technique revealed that the mitochondrial calcium uniporter (MCU) and essential MCU regulatory element (EMRE) are the core subunits of the complex. Furthermore, detailed structure-function analyses of the core subunits (MCU and EMRE) were performed. In this review, the regulatory mechanism of mitochondrial Ca(2+) uptake is discussed.