Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Friend erythroleukaemic cells can be induced to mature along the erythroid differentiation pathway when an inducing agent such as dimethyl sulphoxide is included in the medium. In the absence of the inducing agent, the 707B line of Friend erythroleukaemic cells is highly agglutinable by the lectins concanavalin A or wheat germ agglutinin. However, 48 h after the induction of differentiation, there is a marked decrease in the agglutination of the cells in the presence of either lectin. This suggests that early in differentiation a change occurs in the cell membrane preceding the onset of globin synthesis which starts approximately 72 h after induction. The change in agglutination by concanavalin A also occurs in the presence of reagents which do not induce haemoglobin synthesis in the 707B line of Friend erythroleukaemic cells but which are able to stimulate the synthesis of this protein in other erythroleukaemic cell lines. The reduction in the agglutinability of the differentiating cells does not seem to result from a reduction in the number of concanavalin A receptors on the cells, nor does it reflect a change in the clustered distribution of concanavalin A receptors in the differentiating cells. Both the control and dimethyl sulphoxide-induced cells show a similar patchy distribution of ferritin-labelled concanavalin A when examined by electron microscopy. Polyacrylamide gel electrophoresis shows little change in the total pattern of protein synthesis by control and differentiating cells when pulse-labelled with [35S] methionine. However, use of 125I-labelled concanavalin A to stain polyacrylamide gels, on which the total proteins of control and differentiating cells had been separated, revealed a profound change in the composition of the concanavalin A-binding proteins. The control, undifferentiated cells contained eleven or more classes of concanavalin A-binding glycoproteins, many of which stained to a lesser degree as the cell density increased. After the onset of differentiation, 2 new concanavalin A-binding glycoproteins appeared within 48 h. One of these proteins has a molecular weight in excess of 180 000 while the other migrated with an apparent molecular weight of approximately 100 000. After erythroid differentiation had progressed for 120 h, these newly synthesized glycoproteins became the major concanavalin A-binding proteins of the erythroleukaemic cells.
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PMID:The interaction of lectins with the surface of differentiating erythroleukaemic cells. 29 32

Trophoblast cells isolated from term human placenta and maintained as an adherent culture express surface receptors for transferrin as indicated by quantitative binding studies using 125I-labelled transferrin. The Kd was 5.3 x 10(-9) M. About 36 per cent of the total cell receptor population was found at the cell surface, the remainder being intracellular. Both 125I-labelled and 59Fe-labelled transferrin were internalized by receptor-mediated endocytosis with similar rates. Pulse-chase experiments showed that 125I-labelled transferrin was recycled and released back to the medium, whereas 59Fe accumulated intracellularly and was released slowly. Polyacrylamide gel electrophoresis followed by autoradiography revealed that 59Fe was accumulated by cells largely in the form of ferritin. A small intracellular pool of low molecular weight 59Fe was also detected. In the presence of monensin, the transfer of 59Fe to ferritin was greatly reduced. The nature and amount of 59Fe released from cells could be modulated by the incubation conditions. In the absence of chelating agents and iron salts, released 59Fe was found to be associated with a low molecular weight fraction as well as with transferrin and ferritin. The low molecular weight 59Fe readily formed a complex with added chelators such as apotransferrin, DTPA or desferrioxamine. The release of 59Fe could be increased by repeatedly changing the medium during the course of the incubation. 59Fe release from trophoblast cells exceeded the release of lactate dehydrogenase and also exceeded the release of 59Fe from 3T3 fibroblasts, suggesting a cell-specific process.
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PMID:Uptake and processing of 125I-labelled transferrin and 59Fe-labelled transferrin by isolated human trophoblast cells. 232 36

Soluble and insoluble forms of ferritins have been purified from dry pea seeds by gel filtration. The insoluble form is called phytosiderin by analogy with animal hemosiderin. Native gel electrophoresis of these two forms have shown that the soluble one (ferritin) is homogenous in size and more compact than the insoluble one (phytosiderin) which is heterogenous in size. However, when iron is removed from these two classes of molecules (apoferritin), they have the same mobility in isopycnic centrifugations. Polyacrylamide-sodium dodecyl sulfate gel electrophoresis revealed a difference in their subunit composition: ferritin molecules are built up from a 28-kDa subunit and phytosiderin from a 26.5-kDa subunit. Partial proteolysis using a Staphylococcus aureus protease indicates a strong relationship between these two polypeptides. Intermediates between these two forms have also been characterized and are composed of both subunits in various amounts. Ferritin and phytosiderin are both able to incorporate iron in vitro into their mineral core. It is also shown that in vitro iron exchange induces ferritin degradation. This degradation is prevented by inhibitors of the Fenton cycle (iron chelates like o-phenanthroline and desferrioxamine B) and reduced by Tris, a radical scavenger. Under in vitro conditions of controlled radical damage the 28-kDa subunit is converted into the 26.5-kDa subunit. Purification of the 28-kDa subunit has allowed us to determine the NH2-terminal sequence. The NH2 extremity of the 26.5-kDa subunit is heterogenous, but the sequence of its main component is identical to the sequence of the 28-kDa subunit downstream residue Leu-21. These data indicate that the 26.5-kDa subunit is produced by radical mediated damage leading to a series of cleavages in the NH2 terminal part of the 28-kDa subunit.
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PMID:Mechanism of the transition from plant ferritin to phytosiderin. 253 54

Mouse peritoneal macrophages have been studied in vitro after ingestion of treated rat, rabbit, or sheep erythrocytes. Under light microscopy, phagocytic vacuoles persist up to 24 h. Macrophages lose benzidine reactivity about 5 h after red cell ingestion, and they become prussian blue positive at 2 days. Ultrastructural studies show little or no ferritin in control macrophages not fed erythrocytes. In contrast, after red cell ingestion, ferritin is widely distributed in the cytoplasmic matrix and in some cytoplasmic granules by 48 h. The Golgi complex, pinocytic vacuoles, endoplasmic reticulum, nuclei, and mitochondria do not contain ferritin. Between 2 and 4 days, ferritin in cytoplasmic granules increases, concomitant with decrease in the ferritin in the cytoplasmic matrix. Evidence is presented suggesting that ferritin in the cytoplasmic matrix is translocated into cytoplasmic granules by autophagy. Polyacrylamide gel studies on macrophages after uptake of red blood cells labeled with radioiron confirm that macrophages produce radiolabeled ferritin by 4 days.
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PMID:Appearance and distribution of ferritin in mouse peritoneal macrophages in vitro after uptake of heterologous erythrocytes. 434 85

Breast cancer markers (TM) are mainly useful for monitoring the course of disease after diagnosis and first line treatment with the control options of primary treatments early recognition of reactivation and efficiency control of palliative treatment. The best single and established marker is a polymorphic epithelial mucin of the MUC-1 family the prototype of which is CA 15-3 (successive markers: MCA, CA-549, TAG-12, CAM 26/29) followed by CEA with lower diagnostic sensitivity and specificity and TPA/TPS reflecting more the proliferative activity. Besides former TM combinations of CEA with one or more less specific markers (e.g. PAM, CRP, beta 2m, ferritin, GCDFP, HCG, total or boney AP, gamma GT), more recent studies recommend the use of fewer markers such as TPA/TPS + CEA or CA 15-3, CA 15-3 + CEA or MCA, CA M26 + CA M29, TAG12 + CA 15-3 + MCA and CEA + CA 15-3 + ESR.
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PMID:Serum marker combinations in human breast cancer (review). 819 81

In order to investigate how endogenous iron can be deposited in vivo on inhaled mineral fibers during early stages of formation of asbestos bodies, in vitro experiments were performed on the adsorption of ferritin onto amosite asbestos. The mineral dust was found to adsorb the protein from an aqueous solution containing 0.3 mg/ml horse spleen ferritin. In order to simulate physiological conditions the aqueous solution was adjusted with 150 mM saline. Polyacrylamide-SDS gel electrophoresis of the desorbed protein showed subunits of approximately 13 and 15 kD, aside from the 20-kD subunit present in the native protein. This suggests that as a result of interactions between ferritin molecules and the solid surface of the mineral fibers, the protein iron core may be released or partially exposed. Data indicate these interactions may have implications in the observed mineral fiber toxicities.
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PMID:Ferritin adsorption on amosite fibers: possible implications in the formation and toxicity of asbestos bodies. 935 79

Polyacrylamide gel electrophoresis and electron microscopy revealed that accumulation of iron-protein in soybean nodules is influenced by nodule age, mutation in bradyrhizobia, and rhizobial/bradyrhizobial strain-soybean cultivar interactions. Iron-protein concentrations (micrograms per milligram protein) were inversely related to heme concentrations (nanomoles per milligram protein), with correlation coefficients (r values) ranging from -0.98 in young nodules to -0.83 in mature ones. Bradyrhizobium japonicum symbiotic mutants HS 129 and HS 145 (Nod(+) Fix(-)) produced nodules high in iron-protein. Electrophoresis of homogenate prepared from nodules on Lee 68 produced by B. japonicum HS 129 yielded two different forms of the iron-proteins, 570 and 600 kilodaltons. The 570 kilodalton iron-protein isolated by preparative polyacrylamide gel electrophoresis behaved like horse-spleen-ferritin in responses to iron-stains, heat stability, ultraviolet absorption spectrum, iron unloading and reloading, and characteristic appearance in electron micrographs. These properties led to the conclusion that the 570 kilodalton iron-protein is phytoferritin. The nodule phytoferritin differed from horse-spleen-ferritin in electrophoretic mobility, serological properties, and molecular size and was distinct from most other known phytoferritins in that it was composed of different subunit types.
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PMID:The occurrence of phytoferritin and its relationship to effectiveness of soybean nodules. 1666 40