Delivery of folates to the cytoplasm of MA104 cells is mediated by a surface membrane receptor that recycles
MA104 cells, as well as several other rapidly dividing tissue culture cells, have a folate-binding protein associated with their cell surface. The protein has the properties of a membrane receptor: (a) 5-methyl(/sup 3/H)tetrahydrofolic acid binds with high affinity (Kd approximately equal to 3 nM); (b) the protein is an integral membrane protein; (c) it appears to deliver physiological concentrations of 5-methyl(/sup 3/H)tetrahydrofolic acid to the inside of the cell; (d) binding activity is regulated by the concentration of folate within the cell. To better understand the mechanism of action of this receptor, we have studied the pathway of folate internalization. We present evidence that during internalization: (a) folate binds to the membrane receptor; (b) the ligand-receptor complex moves into the cell; (c) the ligand is released from the receptor in an acidic intracellular compartment and moves into the cytoplasm; and (d) the unoccupied receptor returns to the cell surface.
- Research Organization:
- Univ. of Texas Southwestern Medical Center, Dallas (USA)
- OSTI ID:
- 6691848
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 263:27
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intrabody-mediated diverting of HP1β to the cytoplasm induces co-aggregation of H3–H4 histones and lamin-B receptor
Affinity labeling of the folate-methotrexate transporter from Leishmania donovani
Related Subjects
FOLIC ACID
MEMBRANE TRANSPORT
MEMBRANE PROTEINS
BIOLOGICAL FUNCTIONS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CELL MEMBRANES
CYTOPLASM
EPITHELIUM
LIGANDS
RECEPTORS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINO ACIDS
ANIMAL TISSUES
AROMATICS
AZAARENES
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DRUGS
FUNCTIONS
HEMATINICS
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PTERIDINES
REACTION KINETICS
TISSUES
VITAMIN B GROUP
VITAMINS
550201* - Biochemistry- Tracer Techniques