Mitochondrial NAD(+) transporter that acts as a 'metabolic gate' in hepatic lipogenesis. Provides NAD(+) substrate to mitochondrial SIRT3 deacetylase and enables its NAD(+)-dependent activities in mitochondrial energy metabolism. This triggers downstream activation of PRKAA1/AMPK-alpha signaling cascade that negatively regulates sterol regulatory element-binding protein (SREBP) transcriptional activities and ATP-consuming lipogenesis to restore cellular energy balance. May transport other mitochondrial metabolites having an aromatic nucleotide and phosphate groups, such as acetyl-CoA. Does not transport amino acids. The transport mechanism remains to be elucidated.