Figure 1.

Uniplex components and uniplex‐mediated mitochondrial Ca²⁺ uptake in the global Ca²⁺ dynamic. (a) The dynamics of the intracellular Ca²⁺ oscillation are finely regulated by the mitochondria, SR/ER, lysosome, and channels located on the PM. When Ca²⁺ is transported from the extracellular space or released from intracellular Ca²⁺ stores, mitochondria will move close to the corresponding channel to take up the elevated [Ca²⁺]_c, thus propagate or restrict Ca²⁺ signals to specific cellular domains. Ca²⁺ influx into mitochondria is mainly mediated by the uniplex. (b) Uniplex is composed of the pore‐forming subunit MCU, MCUb, EMRE, MCUR1, MICU1, MICU2, and MICU3. All these molecules localize at the inner mitochondrial membrane. MICU family protein or EMRE molecule contains only single TMD. Both MCU and MCUb contain two TMDs, while both N‐ and C‐terminals face the mitochondrial matrix. With two TMDs, N‐ and C‐terminals of MCUR1 face the mitochondria inner membrane space