MICU1 and MICU2, two peas in a pod or entirely different fruits?

Fluctuations in mitochondrial matrix Ca plays a critical role in matching energy production to cellular demand through direct effects on oxidative phosphorylation and ATP production. Disruption in mitochondrial Ca homeostasis, particularly under pathological conditions such as ischemia or heart failure, can lead to mitochondrial dysfunction, energy deficit, and eventually death of cardiomyocytes. The primary channel regulating acute mitochondrial Ca influx is the mitochondrial Ca uniporter (mtCU), which is regulated by the mitochondrial Ca uptake (MICU) proteins that were examined here.