Key regulator of mitochondrial calcium uniporter (MCU). Modulates the activity of the mitochondrial calcium uniporter protein mcu-1 depending on the level of intracellular calcium in PLM touch receptor neurons following axonal injury (PubMed:31983639). The topology is subject to debate. Expressed at low levels in PLM touch receptor neurons, germ cells, epidermis, and muscles. Belongs to the MICU1 family. MICU1 subfamily.