Plasma membrane transporter mediating the uptake by cells of the water soluble vitamin B2/riboflavin that plays a key role in biochemical oxidation-reduction reactions of the carbohydrate, lipid, and amino acid metabolism (, ). Humans are unable to synthesize vitamin B2/riboflavin and must obtain it via intestinal absorption .
(Microbial infection) May function as a cell receptor to retroviral envelopes similar to the porcine endogenous retrovirus (PERV-A).
Subcellular locations: Cell membrane
Widely expressed. Highly expressed in the testis, placenta and small intestine. Expressed at lower level in other tissues.