The function of SLC25A33 (solute carrier family 25 member 33, ENSG00000171612) is as follows. Mitochondrial transporter that imports/exports pyrimidine nucleotides into and from mitochondria. Selectively transports uridine, thymidine, guanosine, cytosine and inosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism (PubMed:25320081). May import (deoxy)nucleoside triphosphates in exchange for intramitochondrial (deoxy)nucleoside diphosphates, thus providing precursors necessary for de novo synthesis of mitochondrial DNA and RNA while exporting products of their catabolism (PubMed:25320081). Participates in mitochondrial genome maintenance, regulation of mitochondrial membrane potential and mitochondrial respiration (PubMed:20453889). Upon INS or IGF1 stimulation regulates cell growth and proliferation by controlling mitochondrial DNA replication and transcription, the ratio of mitochondria-to nuclear-encoded components of the electron transport chain resulting in control of mitochondrial ROS production (PubMed:17596519, PubMed:20453889). Participates in dendritic cell endocytosis and may associate with mitochondrial oxidative phosphorylation (PubMed:14715278). {ECO:0000269|PubMed:14715278, ECO:0000269|PubMed:17596519, ECO:0000269|PubMed:20453889, ECO:0000269|PubMed:25320081}.