Electroneutral antiporter that mediates the transport of adenyl 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 adenyl nucleotide pool could adapt to changing cellular energetic demands and indirectly regulate adenyl nucleotide-dependent metabolic pathways (PubMed:15123600, PubMed:22015608). In vitro, a low activity is also observed with guanyl and pyrimidine nucleotides (PubMed:15123600). May play a role in protecting cells against oxidative stress-induced cell death, by buffering calcium levels in the mitochondrial matrix through the formation of calcium-phosphate precipitates (PubMed:22015608, PubMed:29100093).
