The function of Ensembl gene identifier ENSG00000129353 (SLC44A2, solute carrier family 44 member 2 (CTL2 blood group)) is as follows. [Isoform 1]: Choline/H+ antiporter, mainly in mitochondria (PubMed:10677542, PubMed:20665236, PubMed:23651124, PubMed:33789160). Also acts as a low-affinity ethanolamine/H+ antiporter, regulating the supply of extracellular ethanolamine (Etn) for the CDP-Etn pathway, redistribute intracellular Etn and balance the CDP-Cho and CDP-Etn arms of the Kennedy pathway (PubMed:33789160). {ECO:0000269|PubMed:10677542, ECO:0000269|PubMed:20665236, ECO:0000269|PubMed:23651124, ECO:0000269|PubMed:33789160}. [Isoform 3]: Does not exhibit choline transporter activity. .