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

Syncytiotrophoblast microvillous plasma membrane (StMPM) preparations were obtained from human full-term placentae by previously published methods of cold saline extraction and phase centrifugation. Purity of these preparations was assessed by electron microscopy, enzyme analysis and hydroxyproline content. IgG, albumin, alkaline phosphatase, transferrin, ferritin and alpha 2-macroglobulin were consistently detected in the aqueous soluble fraction from sodium deoxycholate-solubilised StMPM preparations by antigenic or electrophoretic analysis, beta 2-Microglobulin was not detected in these preparations. Up to 21 discrete protein bands could be demonstrated by SDS--PAGE, and their molecular weights determined. Many of these components need to be further identified, including a glycoprotein of molecular weight 36 500 which was particularly prominent. The soluble fraction from StMPM preparations gave a single strong precipitin reaction in immunodiffusion against wheat germ agglutinin, but not against other lectins studied.
 ...
PMID:Characterisation of the soluble fraction of human syncytiotrophoblast microvillous plasma membrane-associated proteins. 55 Nov 70

1. A standardized decompensation and recompensation of iron homeostasis has been produced by a change-over from normal to iron deficiency and back. 2. Under these conditions the 59Fe uptake into transferrin and ferritin of the mucosal "cytosol" and SDS treated "membrane" fraction has been measured together with the 59Fe amount transferred into the body. 3. The increase of the intestinal 59Fe absorption due to a progressive iron deficiency is associated with an increase of the 59Fe uptake into the mucosal transferrin of the "cytosol" and the "membrane" fraction; the reverse is observed with regard to mucosal ferritin. 4. Three days after the re-establishment of normal conditions the 59Fe absorption was lowered to normal values, while the 59Fe uptake into mucosal ferritin achieved again normally high values. 5. The high apparent rate of absorption in iron deficient animals decreased during the last 50 min after injection of the 59Fe labelled test dose. The 59Fe content in the ferritin fraction increased simultaneously, whereas the 59Fe content in the transferrin fraction remained the same. 6. The conclusion is drawn that the intestinal iron absorption is regulated by both mucosal iron binding proteins. Mucosal transferrin is responsible for the increase of absorption in iron deficiency while mucosal ferritin is responsible for the inhibition of iron absorption when the iron homeostasis recompensats.
 ...
PMID:Mucosal transferrin and ferritin factors in the regulation of iron absorption. 59 98

The surface complex of Euglena has been examined intact and after isolation and purification by the use of mild sonication to disrupt cells. In intact cells the surface complex (pellicle complex) is oriented in a series of parallel ridges and grooves, and possesses among other components a characteristic group of four to seven microtubules. Isolated pellicles retain the ridge and groove pattern but no microtubules are present. Isolates yielded at least three major polypeptides on SDS acrylamide gels; one or more of the polypeptides are postulated to be identical with a submembrane layer present in both intact and isolated pellicles; one polypeptide appears to be in or on the surface membrane. Antibodies directed against the isolated pellicles were conjugated directly or indirectly to fluorescein, latex spheres, or ferritin. In appropriate experiments with these antibody conjugates, it has been found that antigenic sites are immobile and that new antigenic sites (daughter strips) are inserted between parental strips in replicating cells. These results together with direct observation of daughter strips by transmission electron microscopy suggest that surface growth in Euglena occurs by intussusception. Microtubules associated with the pellicle complex are postulated to play a role in the development of new daughter strips, and possibly also in cell movements.
 ...
PMID:Immunological and structural evidence for patterned intussusceptive surface growth in a unicellular organism. A postulated role for submembranous proteins and microtubules. 81 92

Apoferritin particles were found in mouse peritoneal macrophages cultured in vitro. They were found as 20S particles in the "ribosomal fraction" of macrophages labeled with L-[14C]glutamic acid. Possibilities that they were breakdown products of ribosomes or of other well-known contaminants of the ribosomal fraction were excluded because they did not incorporate [5-3H]uridine. They were resistant to RNase and were relatively resistant to detergent. The antibody against horse spleen apoferritin precipitated about 70% of the particles in the 20S region, judging by measurement of radioactivity. On in vitro incubation with Fe2+ and suitable oxidizing agents the sedimentation coefficient of 80% of the 20S particles changed to about 60S, which corresponds to that of ferritin. SDS-polyacrylamide gel electrophoresis revealed the presence of subunit structures with the same molecular size as that of mouse liver apoferritin. Under the electron microscope, the particles appeared spherical with a relatively uniform diameter of about 130 A.
 ...
PMID:Synthesis of apoferritin in mouse peritoneal macrophages. Characterization of 20 S particles. 82 42

In an effort to isolate genes involved in the progression of colonic cells leading to a carcinoma, we used as a model 2 rat colon-carcinoma cell lines selected from the same tumor, differing by their tumorigenicity. When soluble, Triton-X-100 extracted, or cytoskeletal proteins from the progressive PROb cells and the regressive REGb cells were analyzed by SDS-PAGE, minor differences were seen. Furthermore, mRNA-cDNA hybridization analyses showed extensive homology between the 2 mRNA populations. Thus, the homology between the 2 clones is high at both the protein and the mRNA levels. A PROb cDNA library was hybridized with 32P-cDNA synthesized from PROb or REGb mRNA. The clones giving a stronger signal when hybridized with the homologous PROb probe were isolated. The specificity of each clone was confirmed by RNA blotting. Most of the positive clones showed a 2- to 3-fold higher expression in PROb cells when compared with REGb cells. One clone (J 13) corresponded to an mRNA 7- to 10-fold more abundant in PROb cells, and was further studied. No gene amplification was detected by Southern blot analysis, indicating that the difference in mRNA content was most likely due to an increased transcription of this gene in PROb cells. Sequencing of the cDNA showed high homology with the rat ferritin light sub-unit. Over-expression of ferritin in PROb cells as compared with REGb cells was confirmed at the protein level using specific antibodies.
 ...
PMID:Isolation of cDNA clones corresponding to genes differentially expressed in two colon-carcinoma cell lines differing by their tumorigenicity. 155 92

Iron regulatory factor (IRF), also called iron responsive element-binding protein (IRE-BP), is a cytoplasmic RNA-binding protein which regulates post-transcriptionally transferrin receptor mRNA stability and ferritin mRNA translation. By using the polymerase chain reaction (PCR) and the sequence published by Rouault et al. (1990) a probe was derived which permitted the isolation of three human IRF cDNA clones. Hybridization to genomic DNA and mRNA, as well as sequencing data indicated a single copy gene of about 40 kb specifying a 4.0 kb mRNA that translates into a protein of 98,400 dalton. By in vitro transcription of a assembled IRF cDNA coupled to in vitro translation in a wheat germ extract, we obtained full sized IRF that bound specifically to a human ferritin IRE. In vitro translated IRF retained sensitivity to sulfhydryl oxidation by diamide and could be reactivated by beta-mercaptoethanol in the same way as native placental IRF. An IRF deletion mutant shortened by 132 amino acids at the COOH-terminus was no longer able to bind to an IRE, indicating that this region of the protein plays a role in RNA recognition. Placental IRF has previously been shown to migrate as a doublet on SDS-polyacrylamide gels. After V8 protease digestion the heterogeneity was located in a 65/70 kDa NH2-terminal doublet. The liberated 31 kDa COOH-terminal polypeptide was found to be homogeneous by amino acid sequencing supporting the conclusion of a single IRF gene.
 ...
PMID:Expression of active iron regulatory factor from a full-length human cDNA by in vitro transcription/translation. 173 1

Ferritins from liver and spleen of both beta-thalassaemia/haemoglobin E (HbE) and non-thalassaemic patients were purified by heating a methanol-treated homogenate, followed by molecular exclusion chromatography. The concentrations of ferritins in the beta-thalassaemia/HbE liver and spleen were calculated as 3.8 and 2.0 mg/g wet tissue. The beta-thalassaemia/HbE ferritin iron/protein ratios were higher than those of normal ferritins. On PAGE, all ferritins gave a single major monomeric band with only very small differences in their mobility. Ferritins from thalassaemic patients also possessed bands corresponding to oligomers. On SDS/PAGE, all ferritins were resolved into two major subunits: H and L with L subunit predominating. While the isoferritin profiles of ferritins from beta-thalassaemia/HbE liver and spleen were similar to each other and to those of normal liver and spleen, some extra bands were present in the acidic region. The microstructure of these pathological ferritins appears to result, to a large degree, from the particular nature and amount of iron loading present.
 ...
PMID:Beta-thalassaemia/haemoglobin E tissue ferritins. I: Purification and partial characterization of liver and spleen ferritins. 207 62

Tissue ferritins from beta-thalassaemia/haemoglobin E heart and pancreas were characterized by native PAGE, SDS/PAGE and isoelectric focussing, and compared with those isolated from corresponding liver and spleen tissue. On PAGE, all ferritins consisted of a single band assigned to the protein monomer. Small differences in electrophoretic mobility were found between the bands. The ferritins were resolved by SDS/PAGE into two major subunits, H and L, corresponding to molecular masses of 22.5 kDa and 19 kDa, respectively. The L subunit was predominant in all cases. The isoferritin profiles of all tissue ferritins were remarkably similar, consisting of a complex pattern of bands which were appreciably more basic than those obtained for horse spleen ferritin. The subunit composition and isoferritin profiles of the four tissue ferritins almost certainly reflect the defense mechanism of the body in synthesizing in all four tissue types a more stable long-term iron-storage isoferritin in order to detoxify and store the excess iron present due to the pathological condition of beta-thalassaemia/HbE.
 ...
PMID:Beta-thalassaemia/haemoglobin E tissue ferritins. II: A comparison of heart and pancreas ferritins with those of liver and spleen. 207 63

We describe a simple method for the affinity purification of specific RNA-binding proteins. DNA sequences corresponding to the protein-binding site of the RNA are subcloned into an in vitro transcription vector between the T7 viral promoter and a poly(A) track. A polyadenylated RNA transcript is bound to poly(U)-Sepharose and subsequently incubated with a cellular extract prepurified on heparin-agarose. Specifically adsorbed proteins are recovered in high yield and purity from the affinity matrix by high salt elution. Using this method we isolated the iron regulatory factor (IRF), a cytoplasmic protein which binds to specific palindromic elements in the 5' and 3' untranslated sequences of ferritin and transferrin receptor mRNA, respectively. Activation and binding of this regulatory factor correlates with increased transferrin receptor mRNA stability and inhibition of ferritin translation. The purified factor from human placenta migrates as a monomer in gel chromatography, but is present in equimolar amounts of two proteins with molecular weights of 95 and 100 kDa when analysed by SDS/PAGE. The two proteins are highly related as judged by the identity of their isoelectric points and their specificity to form RNA-protein complexes.
 ...
PMID:A high yield affinity purification method for specific RNA-binding proteins: isolation of the iron regulatory factor from human placenta. 210 65

Incubation of a 90-kilodalton ferritin repressor protein (FRP), either free or complexed with an L-ferritin transcript, with hemin or Co3+-protoporphyrin IX prevented subsequent repression of ferritin synthesis in a wheat germ extract. Neither FeCl3 in combinations with H2O2, nor Fe3+ or Fe2+ chelated with EDTA, nor Zn2+-protoporphyrin IX, nor protoporphyrin IX caused significant inactivation of FRP. FRP that had been inactivated by hemin remained chemically intact, as revealed by SDS-polyacrylamide gel electrophoresis. Inclusion of chelators of iron or free radical scavengers did not alter the inactivation produced by hemin. These and other results indicate that hemin derepresses ferritin synthesis in vitro.
 ...
PMID:Derepression of ferritin messenger RNA translation by hemin in vitro. 229 94


1 2 3 4 5 6 7 8 9 10 Next >>