Biomaterial Database

Transferrin and iron uptake by rat reticulocytes. 1985

H Kohno, and R Tokunaga

The uptake of transferrin labeled with 3H and 59Fe by rat reticulocytes was studied to clarify the characteristics of the uptake process and intracellular transport. Rat reticulocytes took up transferrin in a saturable, time- and temperature-dependent manner. Scatchard analysis of the binding parameters indicated that transferrin molecules were bound to cell-surface receptors with high affinity. Monodansyl- cadaverine, a potent inhibitor of transglutaminase, reduced the amount of internalized transferrin but has no effect on the total amount of cell-associated transferrin, suggesting that transferrin is taken up by rat reticulocytes via receptor-mediated endocytosis. About 50% of the internalized 3H label was released from the cells after reincubation for 1 h in fresh medium. In contrast, no release of 59Fe label was observed. By immunoprecipitation and subsequent SDS-PAGE the released 3H-labeled product was identified as apotransferrin. Lysosomotropic reagents and a proton ionophore reduced the uptake of 59Fe. These results indicated that iron was removed from transferrin at an intracellular site in an acidic environment. The released iron was found not to associate with any intermediate ligands before it was utilized for heme synthesis in mitochondria.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008247	Lysosomes	A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured or undergoes MEMBRANE FUSION. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed).	Autolysosome,Autolysosomes,Lysosome
D008297	Male		Males
D011503	Transglutaminases	Transglutaminases catalyze cross-linking of proteins at a GLUTAMINE in one chain with LYSINE in another chain. They include keratinocyte transglutaminase (TGM1 or TGK), tissue transglutaminase (TGM2 or TGC), plasma transglutaminase involved with coagulation (FACTOR XIII and FACTOR XIIIa), hair follicle transglutaminase, and prostate transglutaminase. Although structures differ, they share an active site (YGQCW) and strict CALCIUM dependence.	Glutaminyl-Peptide Gamma-Glutamyltransferases,Protein-Glutamine gamma-Glutamyltransferases,Transglutaminase,Gamma-Glutamyltransferases, Glutaminyl-Peptide,Glutaminyl Peptide Gamma Glutamyltransferases,Protein Glutamine gamma Glutamyltransferases,gamma-Glutamyltransferases, Protein-Glutamine
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D011990	Receptors, Transferrin	Membrane glycoproteins found in high concentrations on iron-utilizing cells. They specifically bind iron-bearing transferrin, are endocytosed with its ligand and then returned to the cell surface where transferrin without its iron is released.	Transferrin Receptors,Transferrin Receptor,Receptor, Transferrin
D012156	Reticulocytes	Immature ERYTHROCYTES. In humans, these are ERYTHROID CELLS that have just undergone extrusion of their CELL NUCLEUS. They still contain some organelles that gradually decrease in number as the cells mature. RIBOSOMES are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the ENDOPLASMIC RETICULUM), hence the name reticulocytes.	Reticulocyte
D002103	Cadaverine	A foul-smelling diamine formed by bacterial DECARBOXYLATION of LYSINE. It is also an intermediate secondary metabolite in lysine-derived alkaloid biosynthetic pathways (e.g., QUINOLIZIDINES and LYCOPODIUM).	1,5-Pentanediamine,BioDex 1,Pentamethylenediamine,1,5 Pentanediamine