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)

Pollen from perennial rye grass (Lolium perenne) is a major cause of type I allergies worldwide. It contains complex mixtures of proteins, among which Lol p II is a major allergen. Previously, we have reported the cloning and sequencing of Lol p II and its expression in fusion with the heavy chain of human ferritin as carrier polypeptide (Sidoli et al., 1993, J. biol. Chem. 268, 21819-21825). Here, we describe the expression, purification and characterization of a recombinant Lol p II overproduced as a non-fusion protein in the periplasm of E. coli. The recombinant allergen was expressed in high yields and was easily purified in milligram amounts. It competed with the natural Lol p II for binding to specific IgE, and it induced allergic responses in skin prick tests, indicating to be immunologically analogous to the natural protein. Biochemical analyses indicate that recombinant Lol p II is a highly stable and soluble monomeric molecule which behaves like a small globular protein.
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PMID:Recombinant allergen Lol p II: expression, purification and characterization. 778 53

A procedure was developed to purify ferritin from the human brain tissue. The preparation is a heavy chain of ferritin. The level of ferritin in biological fluids was evaluated using the sandwich solid-phase immunoassay. This fraction of ferritin was found in the cerebrospinal fluid of patients with brain tumors. Content of the ferritin heavy chain in cerebrospinal fluid correlated with the rate of brain tissue malignancy.
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PMID:[Immunoenzyme analysis of ferritin in diagnosing brain tumors]. 779 96

We have purified a cell growth factor from a human lung cancer cell line, T3M-30, which was established in a protein-free chemically defined medium. The factor, designated carcinoma-derived growth factor (CD-GF), stimulated proliferation of a variety of cells, including human leukemia cells, HL-60, and melanoma cells, SK-28. Half-maximum stimulation by the purified CD-GF was achieved at a concentration of 40 ng/ml. In the purified CD-GF, two major protein bands of 24 kDa and 22 kDa were identified on a SDS polyacrylamide gel. The partial amino acid sequences of the 24 kDa protein were determined from two peptide fragments obtained by V8 protease treatment. The partial sequences were identical to those of heavy chain of human ferritin. The activity of the purified CD-GF was coprecipitated completely with a monoclonal antibody to heavy chain of ferritin. Ferritin has been considered to inhibit cell growth. However, human heart ferritin was capable of stimulating the growth of HL-60 cells. These results suggest that CD-GF is related to ferritin and ferritin is a growth factor of HL-60 leukemia cells.
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PMID:Purification of a cell growth factor from a human lung cancer cell line: its relationship with ferritin. 792 95

Neonatal (3 day old) rat oligodendrocytes grown in monolayer culture and exposed to increasingly hypoxic culture conditions showed increased Tran35S-label incorporation into a 22-kDa protein. Reoxygenation of cultures reversed the synthesis of the protein. Amino acid sequencing of a peptide derived from the purified protein revealed a 13 amino acid sequence with complete identity to a human heavy chain subunit of ferritin. This was confirmed by two-dimensional gel electrophoresis, immunoprecipitation, and western blot analysis with antiferritin antibody. In addition, hypoxia was able to induce the synthesis of ferritin in a cell line derived from human oligodendroglioma cells but not in astrocytes or neurons. Actinomycin D (1-15 micrograms/ml) treatment did not block the hypoxic induction of ferritin synthesis, whereas cycloheximide (1 microM) gave complete inhibition. Northern blot analysis showed that ferritin mRNA levels remained unchanged in both control and hypoxic oligodendrocytes and human oligodendroglioma cells, suggesting that the synthesis of ferritin was translationally rather than transcriptionally regulated by hypoxia. In neither oligodendrocytes nor the oligodendroglioma was there any cross-reaction with an antibody to alpha B-crystallin, the 22-kDa protein induced in astrocytes by various types of stress, further suggesting the specificity of hypoxic induction of ferritin in oligodendrocytes.
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PMID:Hypoxia specifically and reversibly induces the synthesis of ferritin in oligodendrocytes and human oligodendrogliomas. 793 1

A capillary electrophoresis (CE) method is described for detecting and quantitating apo and holo ferritins from horse spleen (HoSF), rat liver (RLF), recombinant human light chain (rLF), recombinant human heavy chain (rHF), site-directed variants of human light chain, and Azotobacter vinelandii bacterial ferritin (AVBF). This procedure is carried out at pH 8.2, where the ferritin molecules are associated into their 24-mers. Protein mobilities as expressed as elution times were clearly resolved and could be used to distinguish one ferritin type from another, providing a means for detecting and quantitating various ferritin species in purified or partially purified states. Measurements of these and other ferritins were also conducted at pH 2.0, where dissociation into their respective subunits occurs. For HoSF and RLF, the individual L and H subunits were resolved and their relative concentrations were determined by integrating the areas of the elution peaks. HoSF gave 89.8% L and 10.2% H and RLF gave 70.7% L and 29.3% H, while rLF, rHF, and AVBF gave only a single subunit, all in agreement with reported values obtained by polyacrylamide gel electrophoresis. CE of HoSF, containing increasing amounts of iron in the interior, in general, showed that protein mobilities increased, reached a plateau, and then slowly decreased with increasing core size, although buffer effects altered this CE behavior to some extent. Such results indicate that species formed early during core formation have individual iron atoms present and differ from those formed later in which the oligomeric iron core has formed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A capillary electrophoresis method for studying apo, holo, recombinant, and subunit dissociated ferritins. 805 67

We have succeeded in long-term cultivation of a human erythroleukemia cell line, K-562-T1 (T. Okabe, M. Fujisawa, and F. Takaku, Proc. Natl. Acad. Sci. USA, 81: 453-455, 1984). The cells grown in a protein-free chemically defined medium have been shown to produce cell growth factors (A. Mihara et al., In Vitro Cell. Dev. Biol., 23: 317-322, 1987). In this study, we have purified a cell growth factor from the conditioned medium that stimulates the proliferation of human leukemia cells, HL-60. In the purified factor, two major protein bands of 24 kDa and 22 kDa were identified on a sodium dodecyl sulfate-polyacrylamide gel. The 22 kDa protein was stained with a monoclonal antibody to the light chain of ferritin. The growth-promoting activity of the purified factor was coprecipitated with a monoclonal antibody to the light chain or heavy chain of human ferritin. These results suggest that K-562-T1 cells produce a cell growth factor that is related to ferritin.
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PMID:Purification and characterization of a cell growth factor from a human leukemia cell line: immunological identity with ferritin. 826 51

Ferritin, a metal-binding protein responsible for maintaining the bioavailability of iron, has been demonstrated in cells of the osteoblastic lineage. Messenger RNAs encoding the light and heavy chain subunits of ferritin were detected in ROS 17/2.8, ROS 25/1, and UMR106 rat osteosarcoma cell lines, in fetal rat calvaria, and in primary cultures of rat calvarial osteoblast-like cells. In vivo, the expression of ferritin light-chain mRNA was observed in both active osteoblasts and in osteocytes. A 450-kD iron-binding protein was immunoprecipitated from ROS 17/2.8 cells by an antiferritin antiserum. This protein comigrated with native ferritin, and could be dissociated into subunits comigrating with ferritin light and heavy chains. Addition of extracellular Fe59-transferrin to cultures of ROS 17/2.8 cells resulted in the sequestration of the iron in intracellular ferritin. These observations demonstrate that cells of the osteoblastic lineage possess a functional ferritin-based iron uptake and storage system capable of regulating metal homeostasis in bone.
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PMID:The iron-binding protein ferritin is expressed in cells of the osteoblastic lineage in vitro and in vivo. 855 25

The iron storage protein ferritin can contribute to or protect against toxicities which involve iron. Iron can catalyze the oxidation of lipid, protein, DNA and various biomolecules that can reduce iron. Iron can be reduced and released from ferritin by the free radical form of various toxins or superoxide resulting from oxygen reduction by chemicals which redox cycle. Iron can also increase ferritin synthesis by an iron-binding protein which releases from an iron-responsive element in mRNA for ferritin. This increase in ferritin synthesis provides a non-reactive storage site for iron. The mechanism by which iron is placed into ferritin is unknown. We propose that it is catalyzed by ceruloplasmin, the copper-containing ferroxidase that loads iron into transferrin. We believe that the ferroxidase activity, thought to reside in the heavy chain of ferritin, is an artifact resulting from ferrous iron autoxidation. We load iron into ferritin with ceruloplasmin so ferritin plus ceruloplasmin is an effective 'antioxidant'.
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PMID:Ferritin as a source of iron and protection from iron-induced toxicities. 859 65

The mechanism of drug resistance to gallium nitrate is not known. Since gallium can be incorporated into ferritin, an iron storage protein that protects cells from iron toxicity, we investigated whether ferritin expression was altered in gallium-resistant (R) CCRF-CEM cells. We found that the ferritin content of R cells was decreased, while heavy chain ferritin mRNA levels and iron regulatory protein-1 (IRP-1) RNA binding activity were increased. IRP-1 protein levels were similar in gallium-sensitive (S) and R cells, indicating that R cells contain a greater proportion of IRP-1 in a high affinity mRNA binding state. 59Fe uptake and transferrin receptor expression were decreased in R cells. In both S and R cells, gallium inhibited cellular 59Fe uptake, increased ferritin mRNA and protein, and decreased IRP-1 binding activity. Gallium uptake by R cells was markedly diminished; however, the sensitivity of R cells to gallium could be restored by increasing their uptake of gallium with excess transferrin. Our results suggest that R cells have developed resistance to gallium by down-regulating their uptake of gallium. In parallel, iron uptake by R cells is also decreased, leading to changes in iron homeostasis. Furthermore, since gallium has divergent effects on iron uptake and ferritin synthesis, its action may also include a direct effect on ferritin mRNA induction and IRP-1 activity.
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PMID:Resistance to the antitumor agent gallium nitrate in human leukemic cells is associated with decreased gallium/iron uptake, increased activity of iron regulatory protein-1, and decreased ferritin production. 911 86

Previously, we generated monoclonal antibodies against chicken corneal cells (Zak, N. B., and Linsenmayer, T. F. (1983) Dev. Biol. 99, 373). We have now observed that one group of these antibodies reacts with a developmentally regulated component of corneal epithelial cell nuclei. This component is the heavy chain of ferritin, as determined by analyses of immunoisolated cDNA clones and immunoblotting of the protein. Immunoblotting also suggests that the nuclear ferritin may be in a supramolecular form that is similar to the iron-binding ferritin complex found in the cytoplasm of many cells. In vitro cultures and transfection studies show that the nuclear localization depends predominantly on cell type but can be altered by the in vitro environment. The appearance of nuclear ferritin is at least partially under translational regulation, as is known to be true for the cytoplasmic form of the molecule. The tissue and developmental distributions of the mRNA for the molecule are much more extensive than the protein itself, and the removal of iron from cultures of corneal epithelial cells with the iron chelator deferoxamine prevents the appearance of nuclear ferritin. At present the functional role(s) of nuclear ferritin remain unknown, but previous studies on cytoplasmic ferritin raise the possibility that it prevents damage due to free radical generation ("oxidative stress") by sequestering iron. Although it remains to be tested whether nuclear ferritin prevents oxidative damage, we find this an attractive possibility. Since the corneal epithelium is transparent and is constantly exposed to free radical-generating UV light, it is possible that the cells of this tissue have evolved a specialized mechanism to prevent oxidative damage to their nuclear components.
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PMID:Ferritin is a developmentally regulated nuclear protein of avian corneal epithelial cells. 913 44


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