![](https://images.newscientist.com/wp-content/uploads/2023/08/09175152/SEI_167046469.jpg)
Mitochondria
The mitochondrial calcium uniporter (MCU) is a transmembrane protein that allows the passage of calcium ions from a cell's cytosol into mitochondria.
The mitochondrial calcium uniporter (MCU) is a transmembrane protein that allows the passage of calcium ions from a cell's cytosol into mitochondria.