Required to maintain cellular respiration. . Mediates the transport of CDP-ribitol (PubMed:34015330). Does not exhibit CMP-sialic acid, UDP-galactose and UDP-N-acetylglucosamine transport activity (PubMed:28167211, PubMed:34015330). . This is the function of SLC35A4 (solute carrier family 35 member A4, Ensembl gene identifier ENSG00000176087).