Mitochondrial calcium uniporter (MCU)

The mitochondrial calcium uniporter (MCU) is an ion channel complex located in the inner mitochondrial membrane that mediates the selective uptake of Ca²⁺ ions from the cytosol into the mitochondrial matrix[1][3][5][6]. Structurally, the core pore-forming subunit is MCU itself, functioning as a multimer, and forming a complex (the "MCU complex" or "uniporter complex") with regulatory subunits MICU1, MICU2, and EMRE[2][3][6][7]. MICU1 and MICU2 are EF-hand-containing proteins that gate the channel in response to cytosolic Ca²⁺ concentration, while EMRE is essential for channel activity[3][6]. MCU-mediated Ca²⁺ uptake is central to the regulation of mitochondrial energy production, modulation of cell death pathways, and integration of cellular calcium signaling; altered MCU function is implicated in diverse diseases, including cardiovascular, neurodegenerative, metabolic, and cancerous conditions[5][7]. The uniporter can be experimentally inhibited by agents such as ruthenium red and Ru360[1][5]. No major approved drugs specifically target MCU, but it is considered a promising therapeutic target for diseases resulting from mitochondrial Ca²⁺ overload or deficiency[5][7].

Other names

MCUMitochondrial calcium uniporter complex (when referring to the full multi-protein assembly)Uniporter (context-dependent)

Inhibition of calcium influx into mitochondria (blockers such as Ru360 and ruthenium red inhibit MCU channel activity and prevent Ca²⁺ accumulation in the mitochondrial matrix) Modulation of mitochondrial energetics and apoptosis by altering Ca²⁺ homeostasis