Feline Leukemia Virus Subgroup C Cellular Receptor 1 (FLVCR1)

FLVCR1 contains 12 transmembrane segments and 3 N-glycosylation sites. FLVCR1 is most closely related to the organic phosphate antiporter and anion/cation symporter subfamilies of the major facilitator superfamily of transporters. Northern blot analysis detected a 7.5-kb transcript in all tissues examined except liver and skeletal muscle and a 2.0-kb transcript in fetal liver, pancreas, kidney, and all hematopoietic tissues.Inhibition of FLVCR in K562 erythroleukemia cells decreased heme export, impaired their erythroid maturation, and led to apoptosis. FLVCR was upregulated at the colony-forming units-erythroid (CFU-E) stage of erythroid differentiation, indicating that heme export is important in primary cells at this stage. Studies of FLVCR expression in cell lines suggested FLVCR also impacts heme trafficking in intestine and liver.