Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.16.3.1 (ceruloplasmin)
5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iron is required for cellular life. However, abnormalities of its metabolism may lead to iron deficiency or iron overload, both conditions which are deleterious. Therefore, stock and distribution of iron in the body must be very stable. Classically, four major proteins are involved in iron metabolism: (a) transferrin which is implicated in its plasmatic transport, (b) transferrin receptor which regulates iron-transferrin uptake, (c) ferritin, the major iron storage protein, and (d) IRP (Iron Regulatory Protein) which regulates both the entry and storage of iron by linking to the IRE (Iron Responsive Element), a nucleotidic sequence found on transferrin receptor and ferritin mRNA. Thus, IRP adapts gene expression to the iron cellular status. Recent data give informations about new proteins involved in iron metabolism: HFE whose gene is mutated in genetic hemochromatosis, ceruloplasmin which permits cellular iron egress and frataxin which is implicated in the exit of iron from mitochondria.
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PMID:[Current data on iron metabolism]. 1052 Apr 10

The application of molecular genetics to haemochromatosis and experimental mutagenesis in animals has transformed our capacity to investigate the unique physiology of iron homeostasis-a key problem in biology and medicine. The identification of HFE, the principal determinant of adult haemochromatosis (HFE1; OMIM 235200) and TfR2, recently implicated in a rarer form of the inherited disorder (HFE3; OMIM 604250), and the promise of candidate genes for juvenile haemochromatosis (HFE2; OMIM 602390) and neonatal haemochromatosis (OMIM 231100) provide the foundation for important studies into the control mechanism of iron balance in humans. The rare conditions atransferrinaemia (OMIM 209300) and acaeruloplasminaemia (OMIM 604290), each associated with tissue iron overload, have already implicated the iron transport ligand transferrin and the copper transporter caeruloplasmin in the control of iron homeostasis. Gene mapping studies in animal mutants with anaemia due to defects in the uptake or tissue transfer of iron have yielded novel proteins involved in iron transport: DMT1 (brush border transporter of ferrous iron) in the mk/mk mouse, hephaestin (basolateral multi-copper ferroxidase) in the sex-linked anaemic mouse (sla) and ferroportin1 (basolateral iron exporter) in zebrafish weh mutants. The discovery of genes that determine heritable defects of iron absorption and regulation in animals and humans thus holds promise for a complete mechanistic understanding of the molecular pathophysiology of iron metabolism.
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PMID:Haemochromatosis: novel gene discovery and the molecular pathophysiology of iron metabolism. 1100 92

As ceruloplasmin (Cp) seems to be involved in iron mobilization, serum Cp levels were measured in 35 patients with hereditary haemochromatosis (HH), 12 with acquired iron overload (AIO) and 36 healthy subjects. Cp was lower in HH patients than in controls (P < 0.001); no difference was found between untreated HH patients and those on a phlebotomy programme (P = 0.07) and between the HH patients carrying the normal and the mutated alleles of the HFE gene (P = 0.8). Cp levels in AIO subjects were significantly higher than in HH patients (P < 0.004) and similar to those of controls (P = 0.2). No differences in albumin, alpha1 acid glycoprotein and copper serum levels were observed in the three groups.
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PMID:Reduced serum ceruloplasmin levels in hereditary haemochromatosis. 1147 72

This review examines the clinical consequences for the practicing hematologist of remarkable new insights into the pathophysiology of disorders of iron and heme metabolism. The familiar proteins of iron transport and storage-transferrin, transferrin receptor, and ferritin-have recently been joined by a host of newly identified proteins that play critical roles in the molecular management of iron homeostasis. These include the iron-regulatory proteins (IRP-1 and -2), HFE (the product of the HFE gene that is mutated in most patients with hereditary hemochromatosis), the divalent metal transporter (DMT1), transferrin receptor 2, ceruloplasmin, hephaestin, the "Stimulator of Fe Transport" (SFT), frataxin, ferroportin 1 and others. The growing appreciation of the roles of these newly identified proteins has fundamental implications for the clinical understanding and laboratory evaluation of iron metabolism and its alterations with iron deficiency, iron overload, infection, and inflammation. In Section I, Dr. Brittenham summarizes current concepts of body and cellular iron supply and storage and reviews new means of evaluating the full range of body iron stores including genetic testing for mutations in the HFE gene, measurement of serum ferritin iron, transferrin receptor, reticulocyte hemoglobin content and measurement of tissue iron by computed tomography, magnetic resonance imaging and magnetic susceptometry using superconducting quantum interference device (SQUID) instrumentation. In Section II, Dr. Weiss discusses the improved understanding of the molecular mechanisms underlying alterations in iron metabolism due to chronic inflammatory disorders. The anemia of chronic disorders remains the most common form of anemia found in hospitalized patients. The network of interactions that link iron metabolism with cellular immune effector functions involving pro- and anti-inflammatory cytokines, acute phase proteins and oxidative stress is described, with an emphasis on the implications for clinical practice. In Section III, Dr. Brissot and colleagues discuss how the diagnosis and management of hereditary hemochromatosis has changed following the identification of the gene, HFE, that is mutated in most patients with hereditary hemochromatosis, and the subsequent development of a genotypic test. The current understanding of the molecular effects of HFE mutations, the usefulness of genotypic and phenotypic approaches to screening and diagnosis and recommendations for management are summarized.
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PMID:Clinical Consequences of New Insights in the Pathophysiology of Disorders of Iron and Heme Metabolism. 1170 34

We have examined transferrin receptor-1, ferroportin, ceruloplasmin, ferritin light and heavy chains, iron regulatory proteins (IRP)-1 and -2, and hepcidin for mutations that might modulate the iron burden of individuals harboring the common mutant hemochromatosis HFE genotype C282Y/C282Y or cause hemochromatosis independent of mutations in the HFE gene. In a group of white, Asian, and African-American normal and iron-overloaded individuals, the coding and flanking regions of these genes were completely sequenced. Numerous coding region and promoter polymorphisms were detected. These were further examined for association with differences in iron accumulation as measured by plasma transferrin saturation and ferritin levels, but no such association could be documented.
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PMID:A study of genes that may modulate the expression of hereditary hemochromatosis: transferrin receptor-1, ferroportin, ceruloplasmin, ferritin light and heavy chains, iron regulatory proteins (IRP)-1 and -2, and hepcidin. 1178 42

Iron and copper are essential transition metals that permit the facile transfer of electrons in a series of critical biochemical pathways. Recent work has identified the specific proteins involved in the absorption, transport, utilization, and storage of iron and copper. Remarkable progress is being made in understanding the molecular basis of disorders of human iron and copper metabolism. This review describes these proteins and examines the clinical consequences of new insights into the pathophysiology of genetic abnormalities affecting iron and copper metabolisms. Hereditary hemochromatosis is the most common genetic disorder of iron metabolism caused by mutations in the HFE gene. Aceruloplasminemia is a rare iron metabolic disorder that results from deficiency of ceruloplasmin ferroxidase activity as a consequence of mutations in the ceruloplasmin gene. Menkes disease and Wilson's disease are inherited disorders of copper metabolism resulting from the absence or dysfunction of homologous copper-transporting ATPases.
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PMID:Genetic disorders affecting proteins of iron and copper metabolism: clinical implications. 1241 92

The presence of steatosis and inflammatory infiltrate in liver biopsies is essential for the diagnosis of non-alcoholic steatohepatitis (NASH). These findings are similar to those with alcoholic liver disease. However, in the NASH-situation alcohol doesn't play an important role. Risk factors for the development of NASH are obesity and diabetes. Most of the patients are clinically asymptomatic. This means, that a diagnosis of NASH is a diagnosis of exclusion: Viral induced, autoimmune, metabolic and toxic liver disease have to be excluded. The disease has a benign clinical course. The risk of cirrhosis is low. So far, there is no established treatment. Preliminary reports suggest a positive effect of weight-loss and ursodeoxycholic acid. Wilson's disease, a copper storage disorder, in which biliary copper excretion is reduced, is inherited as an autosomal recessive trait. Most patients with Wilson disease become symptomatic between the ages of 6 and 15. In about 90% of patients serum ceruloplasmin levels and serum copper concentrations are reduced. Copper excreation is increased. Histologic examination of liver biopsy specimens reveals fatty infiltration, Mallory bodies and ballooned glycogen nuclei, abnormalities which are also found in alcoholic liver disease. The definitive diagnostic parameter is the quantitative determination of liver copper content (> 250 micrograms/g dryweight). Untreated Wilson disease is always fatal. Lifelong treatment with anti-copper drugs are essential, D-penicillamine being the firstline therapy. Hereditary hemochromatosis (HH) is an iron overload disease inherited as an autosomal recessive trait. The frequency of the disease is high. The first symptoms usually can be found at the age of 20-50 years. Arthralgia develops in up to 50% of the patients. Many organs are involved, most often the liver. The organ is usually enlarged, transaminases are always moderately elevated. Laboratory findings disclose a marked elevation in serum ferritin and transferrin saturation. More than 80% of HH-patients are homozygous for the C282Y-mutation in the HFE-gene. The firstline treatment of HH is phlebotomy. Treatment is lifelong. When serum ferritin drops below 50 micrograms/l, the frequency of phlebotomy should be reduced (4-12 per year). If the patient already has cirrhosis, the risk of HCC is very high.
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PMID:[Rare, but important chronic liver diseases]. 1250 71

Hereditary hemochromatosis is characterized by marked variation of expression of the defect: very few homozygotes with the C282Y/C282Y HFE genotype have full-blown clinical disease, a larger number show biochemical stigmata of iron overload, and some seem normal biochemically. The following candidate genes have been examined in detail to determine whether polymorphisms in them may be responsible for this variation: transferrin, transferrin receptor 1, transferrin receptor 2, ferritin-L, ferritin-H, IRP1, IRP2, HFE, beta(2) microglobulin, mobilferrin/calreticulin, ceruloplasmin, ferroportin, NRAMP1, NRAMP2 (DMT1), haptoglobin, heme oxygenase-1, heme oxygenase-2, hepcidin, USF2, ZIRTL, duodenal cytochrome b ferric reductase (DCYTB), TNFalpha, keratin 8, and keratin 18. The coding sequence, exon-intron junctions, and promoters of each of these genes was sequenced in DNA from 20 subjects: 5 HFE C282Y/C282Y with clinical disease, 5 HFE C282Y/C282Y with normal/low ferritin levels and no disease, 5 wt/wt with high ferritin and transferrin saturation, and 5 wt/wt normal controls. When coding or promoter polymorphisms were encountered, DNA from large numbers of ethnically defined subjects was examined for these polymorphisms and a relationship between their existence and abnormalities of iron homeostasis was sought. Only in the case of one transferrin mutation did we find a strong relationship between the polymorphism and iron deficiency anemia. The putative genes that affect the expression of HFE mutations remain elusive.
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PMID:Seeking candidate mutations that affect iron homeostasis. 1254 38

The mRNAs of proteins involved in iron metabolism were measured in isolated hepatocytes, Kupffer cells, sinusoidal endothelial cells (SECs), and hepatic stellate cells (HSCs). Levels of type I hereditary hemochromatosis gene (HFE), transferrin, hepcidin, transferrin receptors 1 and 2 (TfR1, TfR2), ferroportin 1 (FPN1), divalent metal transporter 1 (DMT1), natural resistance-associated macrophage protein 1 (Nramp1), ceruloplasmin, hephaestin, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH), were measured by quantitative reverse-transriptase polyerase chain reaction (qRT-PCR). We show that hepatocytes express almost all the iron-related genes tested, in keeping with their central role in iron metabolism. In addition, hepatocytes had 10-fold lower TfR1 mRNA levels than TfR2 and the lowest levels of TfR1 of the 4 cell types isolated. Kupffer cells, which process senescent red blood cells and recycle the iron, had high levels of ferroportin 1, ceruloplasmin, and hephaestin mRNA. Most important, of all the cell types tested, hepatocytes had the highest level of HFE mRNA, a factor of 10 higher than Kupffer cells. In situ hybridization analysis was conducted with rat liver sections. Consistent with the qRT-PCR analysis, HFE gene expression was localized mainly in hepatocytes. Western blot analysis confirmed this finding. Unexpectedly, HSCs also had high levels of DMT1 and ferroportin, implicating them in either iron sensing or iron cycling.
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PMID:Localization of iron metabolism-related mRNAs in rat liver indicate that HFE is expressed predominantly in hepatocytes. 1456 38

Primary iron overload may be relatively common in African Americans, but its cause is incompletely understood. Thus, we evaluated genotype and phenotype characteristics of unselected African American index patients with primary iron overload who reside in central Alabama. All had hepatic iron concentration > or =30 micromol/g dry wt or > or =2.0 g of iron mobilized by phlebotomy to achieve iron depletion. Genotype analyses were performed in African American control subjects from the same region. There were 23 patients (19 men, 4 women); mean age at diagnosis was 52 +/- 12 years (1 SD) (range 32-69 years). Nine (39.1%) reported that they consumed > or =45 g of ethanol daily; five had chronic hepatitis C. Eight had some form of hemoglobinopathy or thalassemia. Mean serum transferrin saturation was 56 +/- 28% (range 15-100%). The geometric mean serum ferritin at diagnosis was 1076 ng/mL [95% confidence interval 297-3473 ng/mL]. Increased stainable liver iron was observed in hepatocytes only in 4 patients, in macrophages only in 8 patients, and in hepatocytes and macrophages in 8 patients. The mean quantity of iron mobilized by phlebotomy (corrected for iron absorbed during treatment) was 5.3 +/- 2.0 g (range 4.0-8.4 g). Iron removed by phlebotomy was greater in patients with hemoglobinopathy or thalassemia than in those without these forms of anemia (6.6 +/- 1.3 g vs 3.9 +/- 1.6 g, respectively; P = 0.0144). Daily consumption of > or =45 g of ethanol or chronic hepatitis C was not associated with an increased or decreased amount of phlebotomy-mobilized iron, on the average. The percentage of index patients positive for HFE C282Y was greater than that of controls (P = 0.0058). The respective percentages of phenotype positivity for HFE H63D, D6S105(8), and HLA-A*03 were similar in patients and controls. HFE S65C, I105T, and G93R were not detected in index or control subjects. Two of 13 patients were heterozygous for the ferroportin allele nt 744 G-->T (Q248H), although the phenotype frequency of this allele was similar in patients and 39 controls. Synonymous ferroportin alleles were also detected in some patients. The ceruloplasmin mutation nt 1099C-->T (exon 6; Arg367Cys) was detected in 1 of 2 patients tested. Abnormal alleles of beta-2 microglobulin, Nramp2, TFR2, hepcidin, or IRP2 alleles were not detected in either of the 2 patients so tested. We conclude that primary iron overload in African Americans is not the result of the mutation of a single gene. HFE C282Y, ferroportin 744 G-->T, and common forms of heritable anemia appear to account for increased iron absorption or retention in some patients.
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PMID:Genotypic and phenotypic heterogeneity of African Americans with primary iron overload. 1463 44


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