Biomaterial Database

Receptor-mediated endocytosis of human transferrin and its cell surface receptor. 1985

J W Larrick, and C Enns, and A Raubitschek, and H Weintraub

We have studied the process of transferrin endocytosis in human erythromyeloid cell line K562 using fluorescein (FL) and rhodamine (RD) labeled iron-saturated transferrin (FeTF), and a fluorescein labeled monoclonal antibody to the transferrin receptor (FL-mAB). Because the antireceptor antibody and FeTF bind to different sites on the TF receptor molecule, it is possible to simultaneously and independently follow receptor and ligand. We have measured the relative amounts of transferrin or antireceptor antibody bound in the presence or absence of proteolytic enzymes using a cell sorter. At 4 degrees C almost all of the FL-TF and the FL-mAB is surface bound in a diffuse pattern. Within minutes of elevating the temperature to 37 degrees C surface aggregates form and the FL-TF is internalized. At this time about one sixth of the transferrin is still surface bound and accessible to papain digestion. The remainder localizes in a perinuclear cluster of vesicles. Monoclonal antibody binds to the cell surface transferrin receptor but is not internalized at 4 degrees C or 37 degrees C. When unlabeled diferric transferrin is added, it promotes the uptake of the Fl-mAB. The addition of goat anti-mouse immunoglobulin also promotes FL-mAB uptake. These studies support the concept that a specific trigger is required for transferrin receptor endocytosis.

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
D007951	Leukemia, Myeloid	Form of leukemia characterized by an uncontrolled proliferation of the myeloid lineage and their precursors (MYELOID PROGENITOR CELLS) in the bone marrow and other sites.	Granulocytic Leukemia,Leukemia, Granulocytic,Leukemia, Myelocytic,Leukemia, Myelogenous,Myelocytic Leukemia,Myelogenous Leukemia,Myeloid Leukemia,Leukemia, Monocytic, Chronic,Monocytic Leukemia, Chronic,Chronic Monocytic Leukemia,Chronic Monocytic Leukemias,Granulocytic Leukemias,Leukemia, Chronic Monocytic,Leukemias, Chronic Monocytic,Leukemias, Granulocytic,Leukemias, Myelocytic,Leukemias, Myelogenous,Leukemias, Myeloid,Monocytic Leukemias, Chronic,Myelocytic Leukemias,Myelogenous Leukemias,Myeloid Leukemias
D008807	Mice, Inbred BALB C	An inbred strain of mouse that is widely used in IMMUNOLOGY studies and cancer research.	BALB C Mice, Inbred,BALB C Mouse, Inbred,Inbred BALB C Mice,Inbred BALB C Mouse,Mice, BALB C,Mouse, BALB C,Mouse, Inbred BALB C,BALB C Mice,BALB C Mouse
D008856	Microscopy, Fluorescence	Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.	Fluorescence Microscopy,Immunofluorescence Microscopy,Microscopy, Immunofluorescence,Fluorescence Microscopies,Immunofluorescence Microscopies,Microscopies, Fluorescence,Microscopies, Immunofluorescence
D010206	Papain	A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.	Tromasin
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
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004705	Endocytosis	Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.	Endocytoses