Mitochondrial inner membrane magnesium transporter required for mitochondrial magnesium homeostasis. Modulates the conductance of the MRS2 channel. Involved in the splicing of mRNA group II introns in mitochondria by affecting mitochondrial magnesium concentrations, which are critical for group II intron splicing. Forms homooligomers. Interacts with MRS2. N-glycosylated. Glycosylation is important for correct localization of the protein. Present with 396 molecules/cell in log phase SD medium. Belongs to the CorA metal ion transporter (MIT) (TC 1.A.35) family.