title: Mechanisms of membrane transport of folates into cells and across epithelia.
abstract: Until recently, the transport of folates into cells and across epithelia has been interpreted primarily within the context of two transporters with high affinity and specificity for folates, the reduced folate carrier and the folate receptors. However, there were discrepancies between the properties of these transporters and characteristics of folate transport in many tissues, most notably the intestinal absorption of folates, in terms of pH dependency and substrate specificity. With the recent cloning of the proton-coupled folate transporter (PCFT) and the demonstration that this transporter is mutated in hereditary folate malabsorption, an autosomal recessive disorder, the molecular basis for this low-pH transport activity is now understood. This review focuses on the properties of PCFT and briefly addresses the two other folate-specific transporters along with other facilitative and ATP-binding cassette (ABC) transporters with folate transport activities. The role of these transporters in the vectorial transport of folates across epithelia is considered.
authors.affiliation: Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Rongbao
authors.initials: R
authors.lastname: Zhao
authors.forename: Ndeye
authors.initials: N
authors.lastname: Diop-Bove
authors.forename: Michele
authors.initials: M
authors.lastname: Visentin
authors.forename: I David
authors.initials: ID
authors.lastname: Goldman
mesh_terms: D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism*; D002831:Choroid Plexus / Q000378:metabolism*; D004848:Epithelium / Q000201:enzymology / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000031:analogs & derivatives / Q000378:metabolism*; D005494:Folic Acid Deficiency / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D058979:Proton-Coupled Folate Transporter / Q000378:metabolism; D058978:Reduced Folate Carrier Protein / Q000378:metabolism
chemical_list: D058979:Proton-Coupled Folate Transporter; D058978:Reduced Folate Carrier Protein; D005492:Folic Acid