Abstract
Previously, two different carrier systems for uptake of reduced folates and the antifolate methotrexate (Mtx) were described: the pH-dependent folate sensitive reduced folate carrier 1 (RFC1) from human, hamster and mouse and a sodium-dependent and folate insensitive Mtx carrier-1 (MTX-1) from rat. It was found that all critical residues of the homologous amino acid sequence were identical. RFC1- as well as MTX-1-mediated uptake of a marker substrate into suitable human and rat cell lines increased with proton concentration, was sodium-dependent at neutral pH, and inhibited by folate at acidic pH. It is concluded that RFC1 and MTX-1 are orthologs.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Sequence
-
Animals
-
Caco-2 Cells
-
Carrier Proteins / genetics*
-
Carrier Proteins / metabolism
-
Cell Line, Tumor
-
Cricetinae
-
Fluorescein / chemistry
-
Fluorescein / metabolism
-
Folic Acid / pharmacology
-
Humans
-
Hydrogen-Ion Concentration
-
Membrane Proteins / genetics*
-
Membrane Proteins / metabolism
-
Membrane Transport Proteins*
-
Methotrexate / analogs & derivatives
-
Methotrexate / antagonists & inhibitors
-
Methotrexate / metabolism
-
Mice
-
Minor Histocompatibility Antigens
-
Molecular Sequence Data
-
Rats
-
Reduced Folate Carrier Protein
-
Sequence Alignment
-
Sequence Homology, Amino Acid
-
Sodium / pharmacology*
-
Spectrometry, Fluorescence
Substances
-
Carrier Proteins
-
Membrane Proteins
-
Membrane Transport Proteins
-
Minor Histocompatibility Antigens
-
Reduced Folate Carrier Protein
-
SLC19A2 protein, human
-
Slc19a1 protein, rat
-
Slc19a2 protein, mouse
-
Folic Acid
-
Sodium
-
Fluorescein
-
Methotrexate