Electroneutral antiporter that mediates the transport of adenine nucleotides through the inner mitochondrial membrane. Originally identified as an ATP-magnesium/inorganic phosphate antiporter, it also acts as a broad specificity adenyl nucleotide antiporter. By regulating the mitochondrial matrix adenine nucleotide pool could adapt to changing cellular energetic demands and indirectly regulate adenine nucleotide-dependent metabolic pathways . Also acts as a regulator of mitochondrial calcium uptake and can probably transport trace amounts of other divalent metal cations in complex with ATP (, ). In vitro, a low activity is also observed with guanyl and pyrimidine nucleotides .
Subcellular locations: Mitochondrion inner membrane
Expressed at low levels in most tissues examined, with highest expression in brain, skeletal muscle and pancreas.