SLC25A4 (also known as ANT1), located at the inner mitochondrial membrane, catalyzes the exchange between cytoplasmic ADP and mitochondrial ATP. This function has been reported also for SLC25A5 (ANT2) and SLC25A6 (ANT3). The adenine nucleotide translocator is thus involved in energy production, in close association with the mitochondrial phosphate carrier, since both transporters provide the ATP synthase with its substrates, ADP and Pi.
References:
Klingenberg M. The ADP and ATP transport in mitochondria and its carrier. Biochim Biophys Acta. 2008 Oct;1778(10):1978-2021. doi:10.1016/j.bbamem.2008.04.011. Epub 2008 May 2. PMID: 18510943.
Clémençon B, Babot M, Trézéguet V. The mitochondrial ADP/ATP carrier (SLC25 family): pathological implications of its dysfunction. Mol Aspects Med. 2013 Apr-Jun;34(2-3):485-93. doi: 10.1016/j.mam.2012.05.006. PMID: 23506884.
Ruprecht JJ, King MS, Zögg T, Aleksandrova AA, Pardon E, Crichton PG, Steyaert J, Kunji ERS. The Molecular Mechanism of Transport by the Mitochondrial ADP/ATP Carrier. Cell. 2019 Jan 24;176(3):435-447.e15. doi: 10.1016/j.cell.2018.11.025. Epub 2019 Jan 2. PMID: 30611538