Mitochondrial transporter that imports purine and pyrimidine nucleotides into the mitochondria. Essential for maintaining mitochondrial structure and function. Appears to be important for mitochondrial gene transcription and mitochondrial respiration. Larval lethal at the third instar stage. Third-instar larva are decreased in size and display reduced locomotion activity. In third stage larvae body wall preparations, mitochondria are abnormally shaped, disorganized and have a significantly higher density. Oxygen consumption rate (i.e. mitochondrial respiration) is also significantly lower than the controls. Belongs to the mitochondrial carrier (TC 2.A.29) family.