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

Fluctuations in mitochondrial matrix Ca²⁺ plays a critical role in matching energy production to cellular demand through direct effects on oxidative phosphorylation and ATP production. Disruption in mitochondrial Ca²⁺ 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 Ca²⁺ influx is the mitochondrial Ca²⁺ uniporter (mtCU), which is regulated by the mitochondrial Ca²⁺ uptake (MICU) proteins that were examined here.