Key regulator of mitochondrial calcium uniporter (MCU) that senses calcium level via its EF-hand domains (    , ). MICU1 and MICU2 form a disulfide-linked heterodimer that stimulates and inhibits MCU activity, depending on the concentration of calcium. MICU1 acts both as an activator or inhibitor of mitochondrial calcium uptake . Acts as a gatekeeper of MCU at low concentration of calcium, preventing channel opening . Enhances MCU opening at high calcium concentration, allowing a rapid response of mitochondria to calcium signals generated in the cytoplasm (, ). Regulates glucose-dependent insulin secretion in pancreatic beta-cells by regulating mitochondrial calcium uptake . Induces T-helper 1-mediated autoreactivity, which is accompanied by the release of IFNG .
Subcellular locations: Mitochondrion inner membrane, Mitochondrion intermembrane space
Expressed in epithelial cell lines. Strongly expressed in epidermal keratinocytes and dermal endothelial cells.