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)

We have recently established a cholangiocellular carcinoma (CCC) cell line, designated KMC-1, from a nude mouse subcutaneous tumor which developed after inoculation of a surgically resected peripheral type CCC from a 62-year-old Japanese male patient. KMC-1 cells grew over a 26-month period and passaged 57 times. These cells retained the morphologic characteristics of both the original tumor and the subcutaneous tumor in the nude mouse, which mainly consisted of irregular tubules and invaded surrounding interstitial tissue in part with an indurate pattern. KMC-1 cells grew in a monolayer pavement-like cell arrangement with tubular formation in part. Some cells and/or glands had a mucin-like substance inside. The doubling time of KMC-1 cells growing in serum-containing medium was 54 h at passage 31. Cell growth in serum-free medium was slow but steady. The number of chromosomes was distributed in range from 73 to 83 with modes of 76 and 78. KMC-1 cells secreted some tumor markers such as DUPAN-2, CA125, TPA, hCG, CA19-9 and ferritin, however, the secretion of DUPAN-2, and CA19-9 and ferritin were only detectable in serum-containing and serum-free medium, respectively. These findings suggest that KMC-1 cells will provide a variety of experimental models for research on CCC and the mechanisms of tumor marker secretion.
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PMID:A new human cholangiocellular carcinoma cell line (KMC-1). 133 97

The steps involved in iron absorption are poorly understood. Although transferrin and ferritin are water soluble, most radioiron in gut homogenates after an intraluminal dose of radioiron is recovered in water-insoluble precipitates. Most radioiron in the precipitates was insoluble in detergents and organic solvents and was characterized as mucins. These isolates bound iron in vitro with a Kd of 9.09 x 10(-5). Similar iron binding was observed with commercial mucins. Iron binding to mucin occurred at acid pH and maintained the iron available for absorption with alkalinization. Similar pH-dependent binding to mucin was observed with zinc, cobalt, and lead. Iron competitively inhibited binding of these metals to mucin. However, iron chelates of ascorbate, fructose, and histidine donated iron to mucin at neutral pH. These data provided a role for gastric HCl and intestinal mucin in absorption of iron and metal cations and partial explanation of the competition for absorption between certain metals from the gut lumen. It is postulated that intestinal mucin delivers inorganic iron to intestinal absorptive cells in an acceptable form for absorption.
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PMID:A role for mucin in the absorption of inorganic iron and other metal cations. A study in rats. 198 14

A simple post-embedding technique for the electron microscopical detection of lectin-binding sites using thin sections of tissues embedded in the resin LR White is described. With this technique, no prior etching of the sections is necessary. The cellular fine structure is well preserved and permits close correlation of the labelling to distinct cellular compartments. After mild aldehyde fixation (4% formaldehyde and 0.5% glutaraldehyde for 30 min), enterocyte brush border, vesicles and lysosomes as well as goblet cell Golgi apparatus and mucin are intensely stained after 30-60 min. The hydrophilia and penetrability of LR White is shown by the formation of oxidized diaminobenzidine reaction product arising from horseradish peroxidase-conjugated lectins. The precipitate not only covers the surface of the sections but is also formed within the resin, as is revealed on cross-sections through thin and semithin sections. The addition of 0.2 M solutions of the appropriate inhibitory sugars prevented staining, which indicates a specific binding. Examples are given of the binding of gold-, ferritin- and peroxidase-conjugated lectins for the purpose of detecting glycoconjugates in various intracellular compartments.
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PMID:Post-embedding localization of glycoconjugates by means of lectins on thin sections of tissues embedded in LR white. 242 41

Fine structural analyses of human pancreatic carcinoma have demonstrated their composition of one major cell type, a mucin secreting cell. In lower grades of differentiation the tumor cells change polarity and reduce mucin production and secretion. Instead numerous small vesicles in the cytoplasm and a high frequency of coated pits and coated vesicles beneath the plasma membrane suggest endocytotic activity. One monoclonal antibody (BW 227/19) produced against pancreatic tumor cells of low differentiation, besides binding to primary pancreatic carcinoma in cytofluorometric studies, also reacted with 80% blood monocytes and with macrophages in a variety of tissues, indicating common antigenic determinants on both cell types. Therefore, monocyte-related functions--endocytosis, lysosomal enzyme secretion, and superoxide anion production--were measured in 5 cell lines of pancreatic carcinomas (two lines established from adenocarcinoma of the colon, two lines from small lung cell carcinomas, and one line from squamous cell carcinoma of the lung). These functions were measured under basal conditions and after exposure to zymosan or immune complexes and were compared to isolated normal monocytes of the human. Endocytotic activity, as measured by the uptake of radiolabeled colloidal gold in 4 out of 5 pancreatic tumor cell lines, showed 50% of the basal activity of monocytes, while other tumor cells had only 20% of this activity. Only pancreatic tumor cells demonstrated increased endocytotic, secretory, and chemiluminescence activity to a similar extent as human monocytes after exposure to zymosan or immune complexes. Fine structural studies using cationized ferritin demonstrated the regular endocytotic pathway with uptake via coated pits and vesicles into endosomes and their transfer to a membrane compartment associated with the Golgi complex. The findings indicate a striking similarity between pancreatic tumor cells in vitro and human monocytes, which could be of importance in the understanding of the biology of these ill-defined tumor cells.
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PMID:Monocyte-related functions expressed in cell lines established from human pancreatic adenocarcinoma. I. Comparative analysis of endocytotic activity, lysosomal enzyme secretion, and superoxide anion production. 281 59

Chrysotile asbestos interacts with mucin-secreting cells of tracheal organ cultures, causing an increase in secretion of mucin into the culture medium. This response occurs in the absence of obvious morphologic damage to tracheal epithelial cells. We speculated that asbestos-induced hypersecretion was regulated by the interaction of fibers with specific carbohydrate residues on the cell surface. To test this hypothesis, lectins, i.e., proteins with a high affinity for mono- and oligosaccharides on the plasma membrane, were added to tissues 30 min before addition of chrysotile. Secretion of mucin into the medium was then determined over a 2-hr period by using incorporation of 3H-glucosamine. Blocking of alpha-D-mannose and alpha-D-glucose residues inhibited chrysotile-induced hypersecretion (p less than 0.05), whereas lectins blocking residues of alpha-D-N-acetylgalactosamine, beta-D-N-acetylglucosamine, alpha-L-fucose and sialic acids were ineffective. Preincubation of cultures with carboxypeptidase A or phospholipase A2, but not with neuraminidase, diminished mucin secretion caused by chrysotile. To determine if the positive surface charge of chrysotile was important in interaction with mucin cells, we examined comparatively the effects of various polycations (cationic ferritin, polylysine, DEAE-dextran) and chrysotile after leaching of fibers to remove Mg2+. Although use of polycations enhanced secretion of mucin, effects were not as striking as those observed with chrysotile. In contrast, leached chrysotile failed to elicit a hypersecretory response. These results suggest the interaction of a positively charged component (presumably Mg2+) of chrysotile with glycolipids and glycoproteins containing terminal residues of alpha-D-mannose or alpha-D-glucose.
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PMID:Studies using lectins to determine mineral interactions with cellular membranes. 631 63

Iron metabolism and its molecular regulation are reviewed. Ferric iron is bound to mucin in the stomach and delivered to the duodenum where it can be absorbed. Iron is transported across the apical membrane of the gut mucosa by integrin. Once within the mucosal cell, iron may be stored, utilized in protein synthesis, or exported to the serum. In the serum, iron is carried by transferrin. Diferric transferrin binds to transferrin receptor on the surface of cells and is endocytosed. In the cell, iron is bound to high and low molecular weight ligand and is thought to shuttle iron within the cell. Iron can be stored intracellularly within ferritin, or can be utilized in a number of iron containing proteins synthesized by the mitochondrion, including heme, aconitase, and cytochromes. The first chain of enzymes in the biosynthesis of heme is erythroid 5-aminolevulinate synthase (eALAS). Intracellular iron concentration regulates the synthesis of ferritin, transferrin receptor, and eALAS, thus controlling our iron metabolism. Iron regulates these proteins post-transcriptionally via iron responsive elements (IRE), which are highly conserved stem-loop structures found in messenger ribonucleic acid (mRNA), and an IRE binding protein (IRE-BP), which responds to increased intracellular iron concentrations by binding the IRE, and repressing mRNA translation or stabilizing the mRNA, depending on whether the IRE is located in the upstream or downstream untranslated regions of the mRNA. Cellular responses to iron depletion and iron over-load can be explained in terms of these regulatory mechanisms.
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PMID:Iron metabolism and its regulation. A review. 776 65

Combined versus separate exposure of male organism to cesium-137 and chemical agents results in a more pronounced hyperferritinemia in the former case. In female chemists the ferritin level is dependent to a considerable extent on the menstrual cycle showing a tendency for the iron-containing protein level to decrease because of the action of a number of chemical agents. The rise of the level of cancer embryonic antigen is more readily seen in persons with high levels of cesium-137. Concentrations of carbohydrate antigen (CA-125) and mucin-like antigen are appreciably higher in female chemists incorporating cesium-137, and in those within the 30-km radius of the ChNPP. The level of thyroglobulin was raised in the chemists having a background incorporation of cesium, the liquidators of the aftermaths, and particularly in those happened to be in the 30-km zone. Each of the unfavourable factors taken separately (chemical agent or cesium-137) had lesser effect on the degree of elevation of TG content and hormone-forming function of the thyroid gland. An additional information has been obtained concerning the risk groups, which, however, serves as an indirect measure of carcinogenic effect various environmental factors exert on the organism.
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PMID:[The effect of environmental factors on the concentration of tumor markers in the blood serum and on the indices characterizing thyroid function]. 790 Mar 50

The absorption of metal ions in the mammalian single-stomached gut is fortunately highly selective, and both luminal and tissue regulation occur. Initially, assimilation of metal ions in an available form is facilitated by the intestinal secretions, chiefly soluble mucus (mucin) that retards hydrolysis of ions such as Cu, Fe and Zn. Metal ions then bind and traverse the mucosally-adherent mucus layer with an efficiency M+ > M2+ > M3+. At the mucosa Fe3+ is probably uniquely reduced to Fe2+, and all divalent cations (including Fe2+) are transported by a membrane protein (such as divalent cation transporter 1) into the cell. This minimizes absorption of toxic trivalent metals (e.g. Al3+). Intracellular metal-binding molecules (such as mobilferrin) may be present at the intracellular side of the apical membrane, anchored to a transmembrane protein such as an integrin complex. This mobilferrin would receive the metal ion from divalent cation transporter 1 and, with part of the integrin molecule, transport the metal to the cytosol for safe sequestration in a larger complex such as ferritin or 'paraferritin'. beta 2-Microglobulin and HFE (previously termed human leucocyte antigen H) may be involved in stabilizing metal mobilferrin-integrin to form this latter complex. Finally, a systemic metal-binding protein such as transferrin may enter the antiluminal (basolateral) side of the cell for binding of the sequestered metal ion and delivery to the circulation. Regulatory proteins, such as HFE, may determine the degree of ion transport from intestinal cells to the circulation. Gradients in pH and perhaps pCa or even pNa could allow the switching of ions between the different transporters throughout this mechanism.
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PMID:The regulation of mineral absorption in the gastrointestinal tract. 1034 52

Components of the insect clot, an extremely rapid forming and critical part of insect immunity, are just beginning to be identified (1). Here we present a proteomic comparison of larval hemolymph before and after clotting to learn more about this process. This approach was supplemented by the identification of substrates for the enzyme transglutaminase, which plays a role in both vertebrate blood clotting (as factor XIIIa) and hemolymph coagulation in arthropods. Hemolymph proteins present in lower amounts after clotting include CG8502 (a protein with a mucin-type domain and a domain with similarity to cuticular components), CG11313 (a protein with similarity to prophenoloxidase-activating proteases), and two phenoloxidases, lipophorin, a secreted gelsolin, and CG15825, which had previously been isolated from clots (2). Proteins whose levels increase after clotting include a ferritin-subunit and two members of the immunoglobulin family with a high similarity to the small immunoglobulin-like molecules involved in mammalian innate immunity. Our results correlate with findings from another study of coagulation (2) that involved a different experimental approach. Proteomics allows the isolation of novel candidate clotting factors, leading to a more complete picture of clotting. In addition, our two-dimensional protein map of cell-free Drosophila hemolymph includes many additional proteins that were not found in studies performed on whole hemolymph.
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PMID:Proteomic analysis of the Drosophila larval hemolymph clot. 1546 69

T cell immunoglobulin-domain and mucin-domain (TIM) proteins constitute a receptor family that was identified first on kidney and liver cells; recently it was also shown to be expressed on T cells. TIM-1 and -3 receptors denote different subsets of T cells and have distinct regulatory effects on T cell function. Ferritin is a spherical protein complex that is formed by 24 subunits of H- and L-ferritin. Ferritin stores iron atoms intracellularly, but it also circulates. H-ferritin, but not L-ferritin, shows saturable binding to subsets of human T and B cells, and its expression is increased in response to inflammation. We demonstrate that mouse TIM-2 is expressed on all splenic B cells, with increased levels on germinal center B cells. TIM-2 also is expressed in the liver, especially in bile duct epithelial cells, and in renal tubule cells. We further demonstrate that TIM-2 is a receptor for H-ferritin, but not for L-ferritin, and expression of TIM-2 permits the cellular uptake of H-ferritin into endosomes. This is the first identification of a receptor for ferritin and reveals a new role for TIM-2.
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PMID:TIM-2 is expressed on B cells and in liver and kidney and is a receptor for H-ferritin endocytosis. 1620 66


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