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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rabbit liver ferritin is unusual since it forms two discrete electrophoretic bands at the beta position of molecular dimers (Santambrogio & Massover, 1987). The present studies have sought to identify the nature of a 170 kDa non-ferritin polypeptide that is uniquely present in the larger beta band. Ultrastructural, immunological and biochemical results all indicate that this polypeptide is a subunit of the plasma protein. alpha-2-macroglobulin. Experimental results show that rabbit serum alpha-2-macroglobulin will bind liver ferritin, and this association induces the de novo formation of the larger beta band. These results thus demonstrate that molecular heterogeneity of ferritin can be caused by its association with a non-ferritin protein. We conclude that alpha-2-macroglobulin is a binder of rabbit tissue ferritin in the circulation; this binding could provide additional means for the receptor-mediated uptake of circulating ferritin.
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PMID:Rabbit serum alpha-2-macroglobulin binds to liver ferritin: association causes a heterogeneity of ferritin molecules. 246 75

This study was undertaken in order to compare the usefulness of three indices of tumour proliferation in detecting primary hepatocellular carcinoma (HCC) and in differentiating this neoplasm from liver cirrhosis. In 10 patients with HCC and in 63 with liver cirrhosis serum alpha-fetoprotein (AFP), tissue polypeptide antigen (TPA) and ferritin were assayed. Increased levels of AFP but not of TPA and ferritin were observed in HCC as compared to liver/cirrhosis. The receiver-operating characteristic curves demonstrated that AFP is more discriminating between HCC and liver cirrhosis than the other two markers. Correlations between liver function tests and serum markers were observed in liver cirrhosis but no in HCC. We can conclude that AFP is more useful than TPA and ferritin in detecting HCC in patients with liver cirrhosis, owing to the high frequency of false positive results of the latter two indices in liver cirrhosis. Liver dysfunction is probably involved in increasing all these markers of malignancy, thus reducing the specificity of these tests.
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PMID:Alpha-fetoprotein, tissue polypeptide antigen and ferritin in diagnosing primary hepatocellular carcinoma in patients with liver cirrhosis. 247 90

A method of affinity purification of a regulatory protein that binds specific RNA sequences is described. RNAs containing the regulatory sequences are transcribed in vitro from oligonucleotide templates, biotinylated, and incubated with unfractionated cytosol. Specific RNA-protein complexes are bound in solution to avidin, and the resulting complex is bound to biotin-agarose beads. The cytosolic binding protein is released from the RNA in high salt, and a second round of purification yields an essentially homogeneous protein. Using this method, we have identified the protein in human liver that binds iron-responsive RNA regulatory sequences. Iron-responsive elements (IREs) are RNA stem-loops present in the mRNAs encoding ferritin and the transferrin receptor. IREs form the basis for the translational regulation of ferritin gene expression and the regulation of transferrin receptor mRNA degradation rates. The IRE binding protein purified by this technique migrates as a 90-kDa polypeptide on SDS/PAGE. The interaction of the purified protein with IRE-containing RNAs can be detected by gel-mobility shift assays or by covalent crosslinking induced by UV irradiation.
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PMID:The iron-responsive element binding protein: a method for the affinity purification of a regulatory RNA-binding protein. 247 19

The structure and properties of the iron-binding proteins transferrin, lactoferrin and transferrin are reviewed. Transferrin and lactoferrin are structurally similar, consisting of a single polypeptide chain and reversibly binding two iron atoms per molecule. Transferrin is found mainly in serum, whereas lactoferrin is found in neutrophils and in external secretions. Transferrin functions mainly as a donor of iron to cells, but there is no established iron-transport role for lactoferrin. Both these proteins may have antimicrobial activity as a result of their ability to sequester iron. Lactoferrin may act principally as a scavenger of iron in conditions where transferrin may not bind iron well, e.g. at low pH. Ferritin is a multisubunit protein capable of binding up to 4,000 iron atoms and serves principally as an iron-storage protein, though it may also serve to detoxify iron. In iron-rich tissues ferritin is largely degraded and the iron is converted to haemosiderin.
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PMID:Iron-binding proteins. 248 82

The synthesis of ferritin is regulated at the translation level in coordination with iron availability. Under conditions of low iron, translation of ferritin mRNA is repressed and the majority of ferritin mRNA is non-polysomal. Upon an increase in iron, translation of ferritin mRNA is derepressed resulting in as much as a 50-100-fold increase in the rate of ferritin synthesis. This regulation is mediated at least in part by a specific translational repressor which binds to a conserved sequence, the iron responsive element, located in the 5'-untranslated region of ferritin mRNA. In this communication we report the purification of such a repressor from rabbit liver. This repressor, which we call the "ferritin repressor protein," has an apparent molecular mass of 90 kDa when analyzed by gel filtration chromatography. It inhibits translation of ferritin mRNA in a highly specific fashion when added to a wheat germ lysate programmed with liver poly(A+) mRNA. In addition, it binds specifically to sequences contained within the first 92 nucleotides of ferritin mRNA, most likely the iron responsive element. Analysis of highly purified repressor by sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that it is composed primarily of a single polypeptide of approximately 90 kDa. Elution of this 90-kDa polypeptide from a sodium dodecyl sulfate gel followed by renaturation and analysis for repressor activity shows that it both binds to the 5'-untranslated region of ferritin mRNA and represses its translation in vitro.
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PMID:Purification of a specific repressor of ferritin mRNA translation from rabbit liver. 256 64

The levels of carcinoembryonic antigeny (CEA), tissue polypeptide antigeny (TPA), CanAg 50, neuron specific enolase (NSE) and ferritin were determined in bronchial secretion and serum of patients with neoplastic and non-neoplastic lung diseases. Simultaneous determination of two or three markers in the serum and in bronchoalveolar lavage (BAL) may be clinically useful for the diagnosis of lung cancer and even for the type of tumor. The positivity of CEA determined simultaneously in serum and in BAL of patients with lung cancer is higher than 80% whereas in patients with benign lung disease it is lower than 40%. The simultaneous assay of TPA in serum and in BAL showed 100% positivity in patients with oat-cell carcinoma, the frequencies of positivity were similar in patients with non-oat-cell carcinoma. For NSE and CanAg CA-50 patients with oat-cell carcinoma showed 100% positivity. Simultaneous assay of ferritin in serum and in BAL gave 85% positivity in patients with oat-cell carcinoma and only 23% in patients with non-oat-cell carcinoma. We conclude that the simultaneous determination of CEA and CanAg CA-50 or NSE in serum and in BAL is a useful aid in the diagnosis of lung malignancy.
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PMID:Tumor markers and lung cancer: correlation between serum and bronchial secretion levels of CEA, TPA, CanAg CA-50, NSE and ferritin. 283 26

We have previously purified an Mr 75,000 protein from cultured human JEG-3 choriocarcinoma cells and showed that this protein is specifically confined to the cytoplasmic side of JEG-3 microvillar membranes. Recently, the Mr 75,000 protein, designated as cytovillin, was found to be expressed also in several other cultured human cell lines and strains, in which it was detected in microvillus-related structures. We now demonstrate the redistribution of cytovillin in herpes simplex type 1 (HSV-1) and Semliki Forest virus (SFV) infected human embryonal fibroblasts. Virus infection induced rapidly numerous microvilli on the apical cell surfaces, and cytovillin was enriched into these newly formed structures as shown by indirect immunofluorescence and immunoferritin electron microscopy. In mock-infected cells treated with the anti-cytovillin antibodies a small amount of ferritin particles and faint fluorescence was detected along the smooth plasma membrane. Only occasional cell surface protrusions were observed in these cells. The enrichment of the cytovillin was first seen 2 h after infection. The isoelectric point (IP) and the mobility of the cytovillin polypeptide in sodium dodecyl sulfate polyacrylamide gel electrophoresis was not altered after this redistribution, suggesting that the protein was not significantly modified during infection. Five RNA+ SFV mutants (ts-1, ts-2, ts-3, ts-5, ts-7) with temperature-sensitive defects in processing and transport of viral envelope glycoproteins to the plasma membrane induced microvilli at the restrictive temperature (39 degrees C) as the wild type virus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Redistribution of Mr 75,000 plasma membrane protein, cytovillin, into newly formed microvilli in herpes simplex and Semliki Forest virus infected human embryonal fibroblasts. 284 3

A cell line, HuH-28, was established in vitro from a patient with cholangiocellular carcinoma (CCC). This cell line has grown slowly, revealing a doubling time of approximately 80 h, and the serial passages were carried out 20 times within 10 months. Light microscopy revealed spindle and polygonal morphology of the cells. Chromosome number of the cells were distributed near the hypotriploid region at passages 3 and 14. HuH-28 cells were not transplantable into nude mice, but secreted some tumor markers including alkaline phosphatase (ALP), gamma glutamyltranspeptidase (GGT), beta 2-microglobulin (BMG), ferritin, elastase-1, and tissue polypeptide antigen (TPA). This HuH-28 cell line will represent a good model for the investigation of carcinogenesis, histogenes, and diagnosis of CCC.
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PMID:Establishment and characterization of a cell line from a human cholangiocellular carcinoma. 285 88

A cell line, HuH-28 was established in vitro from a patient with cholangiocellular carcinoma (CCC). This cell line has been in continuous culture over 10 month period with slow growth potential. HuH-28 was composed of spindle-shaped cells as major population besides a small percentage of polygonal-shaped cells. Chromosome number of the cells were distributed near the hypotriploid region on the 3rd passage. HuH-28 cells were not transplantable into nude mice, but secreted some tumor markers including alkaline phosphatase (ALP), gamma glutamyltranspeptidase (GGT), beta 2-microglobulin (BMG), ferritin, elastase-1 and tissue polypeptide antigen (TPA). This HuH-28 cell line will represent a good model for the investigation of carcinogenesis, histogenesis+ and diagnosis of CCC.
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PMID:[Establishment and characterization of a human cholangiocellular carcinoma cell line]. 285 43

We evaluated whether assay of tissue polypeptide antigen (TPA) in the serum ia valuable for the determination of cancer stages compared to other tumor markers such as CEA, AFP, and ferritin. The study population consisted of 79 gastric cancer patients and 212 patients with benign gastroenteric disease. The percentage of positive cases for TPA (higher than 200u/l) was 41% in gastric cancer and 20% in active peptic ulcer. Serum TPA levels in well differentiated carcinoma and signet ring cell carcinoma were higher than that in other histological types. Serum TPA levels correlated well with the stage of the gastric cancer.
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PMID:[Clinical study on tissue polypeptide antigen (TPA) in gastric cancer]. 299 64


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