Related Experiment Videos
Membrane transport of folate compounds
F M Huennekens1, K S Vitols, L E Pope
1Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037.
Journal of Nutritional Science and Vitaminology
|January 1, 1992
Summary
Cells use membrane transport systems to acquire essential folates and antifolates like Methotrexate (MTX). Studies in Lactobacillus casei and L1210 cells reveal distinct transporter mechanisms crucial for cell replication and cancer therapy.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Folic acid is vital for cell replication and is acquired via membrane transport systems in prokaryotes and eukaryotes.
- These systems are crucial for internalizing antifolates, such as Methotrexate (MTX), used in cancer chemotherapy.
Purpose of the Study:
- To investigate the characteristics and mechanisms of folate transport systems in prokaryotic (Lactobacillus casei) and eukaryotic (L1210 mouse leukemia) models.
- To understand the role of these transporters in folate uptake and antifolate drug internalization.
Main Methods:
- Purification and characterization of the membrane-associated folate transport protein from L. casei.
- Analysis of folate transport kinetics (Kt values) in L. casei and L1210 cells.
- Utilizing fluorescent and biotinylated probes for transporter visualization and purification.
Main Results:
- L. casei possesses a single high-affinity folate transporter (nanomolar Kt) whose expression is repressed by high folate concentrations.
- L1210 cells exhibit two folate transport systems: a high-affinity system (nanomolar Kt) and a low-affinity system (micromolar Kt) for folates and MTX.
- Covalent attachment of folate and MTX derivatives enabled transporter visualization and purification.
Conclusions:
- Folate transport systems are essential for cellular nutrition and drug delivery, with distinct mechanisms in prokaryotes and eukaryotes.
- Characterization of these transporters provides insights into folate metabolism and antifolate drug efficacy in cancer treatment.