Transferrin-Binding Protein A: A subtype of bacterial transferrin-binding protein found in bacteria. It forms a cell surface receptor complex with TRANSFERRIN-BINDING PROTEIN B.Transferrin-Binding Protein B: A subtype of bacterial transferrin-binding protein found in bacteria. It forms a cell surface receptor complex with TRANSFERRIN-BINDING PROTEIN A.Transferrin-Binding Proteins: A class of carrier proteins that bind to TRANSFERRIN. Many strains of pathogenic bacteria utilize transferrin-binding proteins to acquire their supply of iron from serum.Transferrin: An iron-binding beta1-globulin that is synthesized in the LIVER and secreted into the blood. It plays a central role in the transport of IRON throughout the circulation. A variety of transferrin isoforms exist in humans, including some that are considered markers for specific disease states.Hemochromatosis: A disorder of iron metabolism characterized by a triad of HEMOSIDEROSIS; LIVER CIRRHOSIS; and DIABETES MELLITUS. It is caused by massive iron deposits in parenchymal cells that may develop after a prolonged increase of iron absorption. (Jablonski's Dictionary of Syndromes & Eponymic Diseases, 2d ed)Iron-Binding Proteins: Proteins that specifically bind to IRON.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Receptors, Transferrin: Membrane glycoproteins found in high concentrations on iron-utilizing cells. They specifically bind iron-bearing transferrin, are endocytosed with its ligand and then returned to the cell surface where transferrin without its iron is released.Iron Overload: An excessive accumulation of iron in the body due to a greater than normal absorption of iron from the gastrointestinal tract or from parenteral injection. This may arise from idiopathic hemochromatosis, excessive iron intake, chronic alcoholism, certain types of refractory anemia, or transfusional hemosiderosis. (From Churchill's Illustrated Medical Dictionary, 1989)Phlebotomy: The techniques used to draw blood from a vein for diagnostic purposes or for treatment of certain blood disorders such as erythrocytosis, hemochromatosis, polycythemia vera, and porphyria cutanea tarda.Histocompatibility Antigens Class I: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.Hepcidins: Forms of hepcidin, a cationic amphipathic peptide synthesized in the liver as a prepropeptide which is first processed into prohepcidin and then into the biologically active hepcidin forms, including in human the 20-, 22-, and 25-amino acid residue peptide forms. Hepcidin acts as a homeostatic regulators of iron metabolism and also possesses antimicrobial activity.Ferritins: Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.Iron Chelating Agents: Organic chemicals that form two or more coordination links with an iron ion. Once coordination has occurred, the complex formed is called a chelate. The iron-binding porphyrin group of hemoglobin is an example of a metal chelate found in biological systems.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Iron Radioisotopes: Unstable isotopes of iron that decay or disintegrate emitting radiation. Fe atoms with atomic weights 52, 53, 55, and 59-61 are radioactive iron isotopes.HLA Antigens: Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.Iron Metabolism Disorders: Disorders in the processing of iron in the body: its absorption, transport, storage, and utilization. (From Mosby's Medical, Nursing, & Allied Health Dictionary, 4th ed)Cation Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.Psoas Muscles: A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the Greek "psoa", the plural meaning "muscles of the loin". It is a common site of infection manifesting as abscess (PSOAS ABSCESS). The psoas muscles and their fibers are also used frequently in experiments in muscle physiology.Iron-Regulatory Proteins: Proteins that regulate cellular and organismal iron homeostasis. They play an important biological role by maintaining iron levels that are adequate for metabolic need, but below the toxicity threshold.Iron Regulatory Protein 1: A multifunctional iron-sulfur protein that is both an iron regulatory protein and cytoplasmic form of aconitate hydratase. It binds to iron regulatory elements found on mRNAs involved in iron metabolism and regulates their translation. Its RNA binding ability and its aconitate hydrolase activity are dependent upon availability of IRON.Iron Regulatory Protein 2: A multifunctional iron-sulfur protein that is both an iron regulatory protein and cytoplasmic form of aconitate hydratase. It binds to iron regulatory elements found on mRNAs involved in iron metabolism and regulates their translation. Its rate of degradation is increased in the presence of IRON.Neisseria gonorrhoeae: A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.Homozygote: An individual in which both alleles at a given locus are identical.Lactoferrin: An iron-binding protein that was originally characterized as a milk protein. It is widely distributed in secretory fluids and is found in the neutrophilic granules of LEUKOCYTES. The N-terminal part of lactoferrin possesses a serine protease which functions to inactivate the TYPE III SECRETION SYSTEM used by bacteria to export virulence proteins for host cell invasion.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Anemia, Iron-Deficiency: Anemia characterized by decreased or absent iron stores, low serum iron concentration, low transferrin saturation, and low hemoglobin concentration or hematocrit value. The erythrocytes are hypochromic and microcytic and the iron binding capacity is increased.Neisseria meningitidis: A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Deferoxamine: Natural product isolated from Streptomyces pilosus. It forms iron complexes and is used as a chelating agent, particularly in the mesylate form.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Homeostasis: The processes whereby the internal environment of an organism tends to remain balanced and stable.Porphyria Cutanea Tarda: An autosomal dominant or acquired porphyria due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in the LIVER. It is characterized by photosensitivity and cutaneous lesions with little or no neurologic symptoms. Type I is the acquired form and is strongly associated with liver diseases and hepatic toxicities caused by alcohol or estrogenic steroids. Type II is the familial form.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Apoferritins: The protein components of ferritins. Apoferritins are shell-like structures containing nanocavities and ferroxidase activities. Apoferritin shells are composed of 24 subunits, heteropolymers in vertebrates and homopolymers in bacteria. In vertebrates, there are two types of subunits, light chain and heavy chain. The heavy chain contains the ferroxidase activity.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Ferric Compounds: Inorganic or organic compounds containing trivalent iron.Kinetics: The rate dynamics in chemical or physical systems.Gallium: A rare, metallic element designated by the symbol, Ga, atomic number 31, and atomic weight 69.72.Genetic Testing: Detection of a MUTATION; GENOTYPE; KARYOTYPE; or specific ALLELES associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing.Iron Isotopes: Stable iron atoms that have the same atomic number as the element iron, but differ in atomic weight. Fe-54, 57, and 58 are stable iron isotopes.Penetrance: The percent frequency with which a dominant or homozygous recessive gene or gene combination manifests itself in the phenotype of the carriers. (From Glossary of Genetics, 5th ed)beta 2-Microglobulin: An 11-kDa protein associated with the outer membrane of many cells including lymphocytes. It is the small subunit of the MHC class I molecule. Association with beta 2-microglobulin is generally required for the transport of class I heavy chains from the endoplasmic reticulum to the cell surface. Beta 2-microglobulin is present in small amounts in serum, csf, and urine of normal people, and to a much greater degree in the urine and plasma of patients with tubular proteinemia, renal failure, or kidney transplants.Iron Compounds: Organic and inorganic compounds that contain iron as an integral part of the molecule.Chromosomes, Human, Pair 6: A specific pair GROUP C CHROMSOMES of the human chromosome classification.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Iron-Sulfur Proteins: A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.CeruloplasminIntestinal Absorption: Uptake of substances through the lining of the INTESTINES.Ferrous Compounds: Inorganic or organic compounds that contain divalent iron.Chelation Therapy: Therapy of heavy metal poisoning using agents which sequester the metal from organs or tissues and bind it firmly within the ring structure of a new compound which can be eliminated from the body.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Mutation, Missense: A mutation in which a codon is mutated to one directing the incorporation of a different amino acid. This substitution may result in an inactive or unstable product. (From A Dictionary of Genetics, King & Stansfield, 5th ed)Liver Cirrhosis: Liver disease in which the normal microcirculation, the gross vascular anatomy, and the hepatic architecture have been variably destroyed and altered with fibrous septa surrounding regenerated or regenerating parenchymal nodules.Aconitate Hydratase: An enzyme that catalyzes the reversible hydration of cis-aconitate to yield citrate or isocitrate. It is one of the citric acid cycle enzymes. EC 4.2.1.3.Point Mutation: A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Transferrins: A group of iron-binding proteins that tightly bind two ferrate ions along with two carbonate ions. They are found in the bodily fluids of vertebrates where they act as transport and storage molecules for iron.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Siderophores: Low-molecular-weight compounds produced by microorganisms that aid in the transport and sequestration of ferric iron. (The Encyclopedia of Molecular Biology, 1994)Liver Diseases: Pathological processes of the LIVER.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
This protein mediates cellular uptake of transferrin-bound iron and mutations in this gene have been associated with hereditary ... 1998). "The hemochromatosis gene product complexes with the transferrin receptor and lowers its affinity for ligand binding". ... is a protein that in humans is encoded by the TFR2 gene. This protein is involved in the uptake of transferrin-bound iron into ... the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein ...
... the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein ... all life forms that use iron bind the iron atoms to proteins. This binding allows cells to benefit from iron while also ... Free radicals can cause damage to a wide variety of cellular structures, and ultimately kill the cell. Iron bound to proteins ... However, some of the intracellular iron is bound to low-affinity complexes, and is termed labile iron or "free" iron. Iron in ...
... the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein ... Thus, transferrin receptor maintains cellular iron homeostasis. TfR production in the cell is regulated according to iron ... binds to the hairpin like structure (IRE) that is in the 3' UTR of the TfR mRNA. Once binding occurs, the mRNA is stabilized ... Transferrin receptor (TfR) is a carrier protein for transferrin. It is needed for the import of iron into the cell and is ...
A major component of this regulation is the protein transferrin, which binds iron ions absorbed from the duodenum and carries ... Durupt, S.; Durieu, I.; Nové-Josserand, R.; Bencharif, L.; Rousset, H.; Vital Durand, D. (2000). "Hereditary hemochromatosis". ... proteins, lipids, and other cellular components. Iron toxicity occurs when the cell contains free iron, which generally occurs ... Gray, N. K.; Hentze, M. W. (Aug 1994). "Iron regulatory protein prevents binding of the 43S translation pre-initiation complex ...
Press RD (December 2001). "Hemochromatosis caused by mutations in the iron-regulatory proteins ferroportin and H ferritin". ... "Hepcidin regulates cellular iron efflux by binding to ferroportin and inducing its internalization". Science. 306 (5704): 2090- ... "A study of genes that may modulate the expression of hereditary hemochromatosis: transferrin receptor-1, ferroportin, ... Ferroportin is inhibited by hepcidin, which binds to ferroportin and internalizes it within the cell. This results in the ...
... but with an iron overload, the ability for transferrin to bind iron is exceeded and non-transferrin bound iron is formed. It ... These tests include complete blood count; hemoglobin electrophoresis; serum transferrin, ferritin, total iron-binding capacity ... Beta thalassemia is a hereditary disease affecting hemoglobin. As with about half of all hereditary diseases, an inherited ... represents a potentially toxic iron form due to its high propensity to induce oxygen species and is responsible for cellular ...
A major component of this regulation is the protein transferrin, which binds iron ions absorbed from the duodenum and carries ... Durupt, S.; Durieu, I.; Nové-Josserand, R.; Bencharif, L.; Rousset, H.; Vital Durand, D. (2000). "Hereditary hemochromatosis". ... proteins, lipids, and other cellular components. Iron toxicity occurs when the cell contains free iron, which generally occurs ... "Iron regulatory protein prevents binding of the 43S translation pre-initiation complex to ferritin and eALAS mRNAs". EMBO J. 13 ...
... (TfR) is a carrier protein for transferrin. It is needed for the import of iron into the cell and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex through receptor-mediated endocytosis. The existence of a receptor for transferrin iron uptake had been recognized over half a century back. Earlier two transferrin receptors in humans, transferrin receptor 1 and transferrin receptor 2 had been characterized and until recently cellular iron uptake was believed to occur chiefly via these two well documented transferrin receptors. Both these receptors are transmembrane, ...
Carbohydrate-deficient transferrin (CDT) is a laboratory test used to help detect heavy ethanol consumption. Transferrin is a serum protein that carries iron through the bloodstream to the bone marrow, where red blood cells are manufactured, as well as to the liver and spleen. Structurally, transferrin is a polypeptide with two N-linked polysaccharide chains. These polysaccharide chains are branched with sialic acid residues. Sialic acid is a monosaccharide carbohydrate. Various forms of transferrin exist, with differing levels of sialylation. The most common form is tetrasialotransferrin, with four sialic acid chains. In persons who consume significant quantities of alcohol (usually more than 4 or 5 alcoholic beverages a day for two weeks or more), the proportion of transferrin with zero, one, or two sialic acid chains is increased. These are referred to as ...
An increased plasma transferrin level is often seen in patients suffering from iron deficiency anemia, during pregnancy, and with the use of oral contraceptives, reflecting an increase in transferrin protein expression. When plasma transferrin levels rise, there is a reciprocal decrease in percent transferrin iron saturation, and a corresponding increase in total iron binding capacity in iron deficient states[14] A decreased plasma transferrin can occur in iron overload diseases and protein malnutrition. An absence of transferrin results from a rare genetic disorder known as atransferrinemia, a condition characterized by anemia and hemosiderosis in the heart and liver that ...
... (TfR) is a carrier protein for transferrin. It is needed for the import of iron into the cell and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex through receptor-mediated endocytosis. The existence of a receptor for transferrin iron uptake had been recognized over half a century back. Earlier two transferrin receptors in humans, transferrin receptor 1 and transferrin receptor 2 had been characterized and until recently cellular iron uptake was believed to occur chiefly via these two well documented transferrin receptors. Both these receptors are transmembrane, ...
... , measured as a percentage, is a medical laboratory value. It is the value of serum iron divided by the total iron-binding capacity. Of the transferrin that is available to bind iron, this value tells a clinician how much serum iron is bound. For instance, a value of 15% means that 15% of iron-binding sites of transferrin are being occupied by iron. For an explanation of some clinical situations in which this ratio is important, see Total iron-binding capacity. The three results are usually reported together. Normal reference ranges are: Serum iron: 60-170 μg/dL (10-30 μmol/L) Total iron-binding ...
... (TIBC) or sometimes transferrin iron-binding capacity is a medical laboratory test that measures the blood's capacity to bind iron with transferrin. It is performed by drawing blood and measuring the maximum amount of iron that it can carry, which indirectly measures transferrin since transferrin is the most dynamic carrier. TIBC is less expensive than a direct measurement of transferrin. The TIBC should not be confused with the unsaturated iron-binding capacity or UIBC (LOINC 2501-5, 22753-8 & 35216-1). The UIBC is calculated by subtracting the serum iron from the TIBC. Taken together with serum iron and percent transferrin saturation clinicians usually perform this ...
... is a carbohydrate-free (desialated) isoform of transferrin, which is almost exclusively found in the cerebrospinal fluid. It is not found in blood, mucus or tears, thus making it a specific marker of cerebrospinal fluid, applied as an assay in cases where cerebrospinal fluid leakage is suspected. Beta-2 transferrin would also be positive in patients with perilymph fluid leaks, as it is also present in inner ear perilymph. Thus, beta-2 transferrin in otorrhea would be suggestive of either a CSF leak or a perilymph leak. Chan D, Poon W, IP C, Chiu P, Goh K (2004). "How useful is glucose detection in diagnosing cerebrospinal fluid leak? The rational use of CT and Beta-2 transferrin assay in detection of cerebrospinal fluid fistula". Asian Journal of Surgery. 27 (1): 39-42. doi:10.1016/S1015-9584(09)60242-6. PMID 14719513. Skedros DG, Cass SP, Hirsch BE, Kelly RH (Oct 1993). "Beta-2 transferrin assay in clinical management ...
... s (PEth) are a group of phospholipids formed only in the presence of ethanol via the action of phospholipase D. Levels of phosphatidylethanols in blood are used as markers of previous alcohol consumption. For this purpose, PEth is more sensitive than carbohydrate deficient transferrin (CDT), urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS). Intake of less than 48 g ethanol/day for three weeks gives a whole blood a PEth concentration of ...
... or CdT may refer to: Carbohydrate deficient transferrin, a transporter protein isoform typically increased in alcoholism Compulsory drug test Current Dental Terminology, a coding system of the American Dental Association Cytolethal distending toxin, a bacterial genotoxin produced by Gram-negative bacteria Clock drawing test cyclododecatriene, a cycloalkene used in the production of polyamides Canadian Deaf Theatre CD Tenerife (Club Deportivo Tenerife), a Spanish football club C.D. Tondela (Clube Desportivo de Tondela), a Portuguese football club Center for Democracy and Technology Centre for Doctoral Training or Doctoral Training Centre, a organisation of PhD programmes at UK universities Children's Dance Theatre, University of Utah China Datang Corporation, a power generation business in the People's Republic of China China Digital Times, a bilingual news website covering Chinese politics Confédération Démocratique du Travail: Democratic Confederation of Labour (DRC), ...
... is one of the transferrin proteins that transfer iron to the cells and control the level of free iron in the blood and external secretions. It is present in the milk of humans and other mammals,[10] in the blood plasma and neutrophils and is one of the major proteins of virtually all exocrine secretions of mammals, such as saliva, bile, tears and pancreas.[15] Concentration of lactoferrin in the milk varies from 7 g/L in the colostrum to 1 g/L in mature milk. X-ray diffraction reveals that lactoferrin is based on one polypeptide chain that contains about 700 amino acids and forms two homologous globular domains named N-and C-lobes. N-lobe corresponds to amino acid residues 1-333 and C-lobe to 345-692, and the ends of those domains are connected by a short α-helix.[16][17] Each lobe consists of two subdomains, N1, N2 and C1, C2, and contains one iron ...
... (born 28 June 1919 in Uppsala, dead 18 September 2001 in Malmö) was a Swedish medical doctor and researcher. Laurell was Professor of clinical chemistry at Lund University. He named the blood plasma protein Transferrin, and discovered that an inherited lack of Alpha 1-antitrypsin could lead to emphysema. In 1976, he was made a member of the Royal Swedish Academy of Sciences. Carl-Bertil Laurell, biographical entry in Nationalencyclopedin (in Swedish ...
The function of receptor-mediated endocytosis is diverse. It is widely used for the specific uptake of certain substances required by the cell (examples include LDL via the LDL receptor or iron via transferrin). The role of receptor-mediated endocytosis is well recognized up take downregulation of transmembrane signal transduction but can also promote sustained signal transduction.[3] The activated receptor becomes internalised and is transported to late endosomes and lysosomes for degradation. However, receptor-mediated endocytosis is also actively implicated in transducing signals from the cell periphery to the nucleus. This became apparent when it was found that the association and formation of specific signaling complexes is required for the effective signaling of hormones (e.g. EGF). Additionally it has been proposed that the directed transport of active signaling complexes to the nucleus might be required to enable signaling as random diffusion is too ...
Kang JS, Cho D, Kim YI, Hahm E, Kim YS, Jin SN, Kim HN, Kim D, Hur D, Park H, Hwang YI, Lee WJ. . (July 2005). "Sodium ascorbate (vitamin C) induces apoptosis in melanoma cells via the down-regulation of transferrin receptor dependent iron uptake. ". J Cell Physiol. 204 (1): 192-7. ...
This protein mediates cellular uptake of transferrin-bound iron and mutations in this gene have been associated with hereditary ... 1998). "The hemochromatosis gene product complexes with the transferrin receptor and lowers its affinity for ligand binding". ... is a protein that in humans is encoded by the TFR2 gene. This protein is involved in the uptake of transferrin-bound iron into ... the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein ...
Protein Coding), Transferrin Receptor 2, including: function, proteins, disorders, pathways, orthologs, and expression. ... This protein mediates cellular uptake of transferrin-bound iron, and may be involved in iron metabolism, hepatocyte function ... Non-classical hereditary hemochromatosis in Portugal: novel mutations identified in iron metabolism-related genes. (PMID: ... Transcription Factor Binding Sites within enhancer. Gene Targets for Enhancer. GH07H100640. 1.3. Ensembl ENCODE 0.7. +1.3. 1347 ...
... hereditary hemochromatosis; heterodimer; HFE; iron; iron overload; protein engineering; protein-protein binding; sedimentation ... TfR binds iron-loaded transferrin (Fe-Tf) from the blood and transports it to acidic recycling endosomes where iron is released ... cellular investigations of the interactions of transferrin receptor with transferrin and the hereditary hemochromatosis protein ... cellular investigations of the interactions of transferrin receptor with transferrin and the hereditary hemochromatosis protein ...
Detection of prevalent genetic alterations predisposing to hemochromatosis and other common human diseases.(Editorial) by ... thus preventing its ability to down-regulate the affinity of transferrin receptor for transferrin-bound iron. The result is a ... Hereditary hemochromatosis: impact of molecular and iron-based testing on the diagnosis, treatment, and prevention of a common ... in the transferrin receptor binding protein FIFE (1). This loss-of-function mutation abolishes HFEs usual cell surface ...
Recent studies in Saccharomyces cerevisiae have shown that in response to iron deficiency, an RNA-binding protein denoted Cth2 ... The Cth2 protein shuttles between the nucleus and the cytoplasm. Once inside the nucleus, Cth2 binds target mRNAs and ... The Cth2 protein contains two Cx8Cx5Cx3H tandem zinc fingers (TZFs) that specifically bind to adenosine/uridine-rich elements ... Recent findings indicate that the TZF-containing tristetraprolin protein also functions in modulating human iron homeostasis. ...
Hereditary hemochromatosis is an iron-overload disorder resulting from mutations in proteins presumed to be involved in the ... Juvenile hemochromatosis patients have decreased urinary levels of hepcidin, a peptide hormone that binds to the cellular iron ... Hepcidin regulates cellular iron efflux by binding to ferroportin and inducing its internalization. Science. 2004. 306:2090- ... which leads to a surfeit of non-transferrin-bound iron that is readily assimilated by parenchymal cells of the liver, heart, ...
Transferrins extremely high affinity for iron, coupled with the fact that two-thirds of the iron binding sites of the protein ... Effects of Iron Overload. Hereditary Hemochromatosis. Total body iron overload occurs most often due either to hereditary ... Transferrin receptors bind iron-transferrin complexes which are taken into endosomes. Iron is separated from transferrin in the ... Cells contain receptors for transferrin on their plasma membranes which mediate cellular iron uptake. ...
Model for the Binding of Fe-Tf and Apo-Tf to TfRThe figures representing each molecule are drawn to scale as an outline around ... Fe-Tf competes for binding to TfR with HFE, the protein mutated in the iron-overload disease hereditary hemochromatosis. We ... Transferrin receptor 1 (TfR) plays a critical role in cellular iron import for most higher organisms. Cell surface TfR binds to ... Fe-Tf competes for binding to TfR with HFE, the protein mutated in the iron-overload disease hereditary hemochromatosis. We ...
... the interactions of transferrin receptor and transferrin receptor 2 with transferrin and the hereditary hemochromatosis protein ... all life forms that use iron bind the iron atoms to proteins. This binding allows cells to benefit from iron while also ... Free radicals can cause damage to a wide variety of cellular structures, and ultimately kill the cell. Iron bound to proteins ... However, some of the intracellular iron is bound to low-affinity complexes, and is termed labile iron or "free" iron. Iron in ...
... increasing number of reports of renal dysfunction and renal iron deposition support an association between increased iron ... patients present with increased levels of iron bound to the circulating transport protein transferrin (transferrin-bound iron; ... Indeed, renal iron loading was observed in several hereditary hemochromatosis mouse models with TBI exposure despite ZIP14 ... Nemeth E et al (2004) Hepcidin regulates cellular iron efflux by binding to ferroportin and inducing its internalization. ...
Iron in low-molecular-weight forms may play a catalytic role in the initiation of free radical... ... Iron is an essential mineral for normal cellular physiology, but an excess can result in cell injury. ... Hereditary hemochromatosis and iron overload diseases.J Gastroenterol Hepatol. 2002;17(suppl 1):191-195.CrossRefGoogle Scholar ... may be key targets of damage by non-transferrin-bound iron in cardiac myocytes. Levels of some antioxidants are decreased ...
However, free iron rapidly catalyzes the generation of damaging free radicals and subsequent oxidant stress. ... Lactoferrin is an iron-binding protein analogous to the iron transporter transferrin; it binds and sequesters iron in areas ... What is Hemochromatosis?. Hemochromatosis is a hereditary condition that causes the body to accumulate an excess of iron. Iron ... Increased levels of non-transferrin bound iron in the blood can enter cells, thus increasing free cellular iron levels. It is ...
... mediates cellular uptake of transferrin-bound iron in a non-iron dependent manner. Hereditary hemochromatosis protein (HFE) ... During iron scarcity, ACO1 and iron-responsive element-binding protein 2 (IREB2) bind with high affinity to RNA stem-loops ... protein (SKP1:FBXL5:CUL1:NEDD8) targets iron-responsive element-binding protein 2 (IREB2) for proteasomal degradation in iron- ... The iron ions that are no longer bound to transferrin are reduced by the metalloreductase STEAP3, an endosomal membrane protein ...
As transferrin iron-binding capacity is exceeded by the large iron flux, non-transferrin-bound iron (NTBI) appears in the ... Hereditary hemochromatosis protein, HFE, interaction with transferrin receptor 2 suggests a molecular mechanism for mammalian ... Systemic iron homeostasis and the iron hormone hepcidin. Iron plays an essential role in cellular metabolism and erythropoiesis ... Non-transferrin bound iron: a key role in iron overload and iron toxicity. Biochim Biophys Acta. 2012;1820(3):403-10. ...
... hereditary hemochromatosis proteins; CREBH - cAMP response element-binding proteins H; EPO-R C erythropoietin receptor; CEBPA C ... iron in its shops from bacteria which have high-affinity iron-binding siderophores for retrieving iron from hosts transferrin ... it binds to moving receptor 1 (TRF1) and displaces hereditary hemochromatosis proteins (HFE) and indicators induction, probably ... CCAAT/enhancer-binding proteins ). Proteins C/EBP binds to promoter and straight reduces hepcidin manifestation like a ...
Disordered iron metabolism as manifested by a low serum iron, decreased serum transferrin, decreased transferrin saturation, ... and reduced iron absorption, is a characteristic feature of the anemia of chronic disease and has been thought to be a major ... increased serum ferritin, increased reticuloendothelial iron stores, increased erythrocyte-free protoporphyrin, ... These proteins include the iron transport protein transferrin and the two forms of its cellular receptor, the iron storage ...
The expression of transferrin receptor, heat shock protein 1B and DnaJ homolog B1 were down-regulated by iron in both muscle ... transcription and cellular stress responses. These may represent novel connections between iron overload and pathological ... encompasses genetic disorders of iron overload characterized by deficient expression or function of the iron-regulatory hormone ... Microarray analysis revealed iron-induced changes in the expression of several genes involved in the regulation of glucose and ...
The multi-grain version contains 18 milligrams of iron per serving, according… ... Transferrin binds iron extraordinarily tightly while it travels through the blood and cellular milieu, preventing any untoward ... Stevens, R.G., Beasley, R.P., & Blumberg, B.S. Iron-binding proteins and risk of cancer in Taiwan. Journal of the National ... The prevalence of hereditary hemochromatosis, in which two defective copies of the HFE gene are present and there are clinical ...
1989) A cytosolic protein binds to structural elements within the iron regulatory region of the transferrin receptor mRNA. ... ShamRL, PhatakPD, NemethE, GanzT (2009) Hereditary hemochromatosis due to resistance to hepcidin: high hepcidin concentrations ... Repression of iron-sulfur clusters increases the functionality of IRP1 as an RNA-binding protein and indirectly alters IRP1- ... 2011) Iron regulatory protein 1 outcompetes iron regulatory protein 2 in regulating cellular iron homeostasis in response to ...
An intestinal nonheme-iron transporter, DMT1, is a validated therapeutic target in hereditary hemochromatosis (HHC) and other ... after binding to albumin and a plasma transport protein to which these vitamins bind with specific high-affinity. Moreover, ... But, aluminium uptake takes place by transferrin-receptor-mediated endocytosis [36]. Few hydrophilic proteins like transferrin ... especially iron and/or manganese. It generates metal deficiency and enhances cellular responses in affected persons [134]. ...
Wild-type HFE protein normalizes transferrin iron accumulation in macrophages from subjects with hereditary hemochromatosis. ... Hepcidin regulates cellular iron efflux by binding to ferroportin and inducing its internalization. Science 2004; 306: 2090- ... evidence for a regulation in response to serum transferrin saturation and non-transferrin-bound iron. Blood 2003; 102: 371-376. ... HIV-1 Nef down-regulates the hemochromatosis protein HFE, manipulating cellular iron homeostasis. Proc Natl Acad Sci U S A 2005 ...
2006) Hereditary hemochromatosis protein, HFE, interaction with transferrin receptor 2 suggests a molecular mechanism for ... The specificity of the response to iron-bound transferrin was further demonstrated by the fact that apo-transferrin was unable ... 2004) Analyses for binding of the transferrin family of proteins to the transferrin receptor 2. Br J Haematol 127:464-73. ... ferroportin1 present on the surface of enterocytes and macrophages leading to its degradation and subsequent cellular iron ...
... which can lead to several disorders including hereditary hemochromatosis and anaemia of chronic disease. An imbalance in iron ... as well as inducers and inhibitors of these proteins and their regulatory pathways. ... Currently, there are limited treatment options for regulating iron levels in patients and thus significant efforts are being ... This axis can be affected by multiple stimuli including plasma iron levels, inflammation and erythropoietic demand. Genetic ...
Iron homeostasis thus relies on the amount that is absorbed from the small intestine. ... The human body has no active mechanism for the excretion of iron. ... Iron status in iron deficiency and overload. NTBI = non-transferrin-bound iron; TIBC = total iron-binding capacity. ... Pietrangelo A. Hereditary hemochromatosis. Biochim Biophys Acta. 2006 Jul. 1763(7):700-10. [Medline]. ...
Organ damage may result from iron overload and manifest clinically as c ... Disturbances in iron metabolism can be genetic or acquired and accordingly manifest as primary or secondary iron overload state ... binds to ferroportin transmembrane protein during states of excess iron or inflammation. This binding leads to internalization ... We expected the transferrin saturation to be ,45%, as seen in hereditary hemochromatosis, the most commonly identified genetic ...
  • Iron accumulation with repeated transfusion reflects the retention of the heme iron from the transfused red cells after they become senscent and are destroyed. (drhui.com)
  • Proteins can contain iron as part of different cofactors, such as iron-sulfur clusters (Fe-S) and heme groups, both of which are assembled in mitochondria. (wikipedia.org)
  • Iron is present in the iron-sulfur clusters and heme groups of the electron transport chain proteins that generate a proton gradient that allows ATP synthase to synthesize ATP (chemiosmosis). (wikipedia.org)
  • Heme groups are part of hemoglobin, a protein found in red blood cells that serves to transport oxygen from the lungs to the tissues. (wikipedia.org)
  • Oxygen is transported from the lungs to the rest of the body bound to the heme group of hemoglobin in erythrocytes. (wikipedia.org)
  • Iron bound to proteins or cofactors such as heme is safe. (wikipedia.org)
  • However, iron can also enter and leave cells not only by itself, but also in the form of heme and siderophores. (wikipathways.org)
  • When entering the cell via the main path (by transferrin endocytosis), its goal is not the (still elusive) chelated iron pool in the cytosol nor the lysosomes but the mitochondria, where heme is synthesized and iron-sulfur clusters are assembled (Kurz et al,2008, Hower et al 2009, Richardson et al 2010). (wikipathways.org)
  • Iron is essential for a variety of fundamental metabolic processes and is incorporated into many proteins in the form of cofactors such as heme and iron-sulfur clusters. (haematologica.org)
  • The mitochondrion is the sole site of heme biosynthesis 5 and the location where the iron-sulfur (Fe-S) cluster is assembled. (arvojournals.org)
  • It has catalytic function within heme or iron-sulfur clusters, or directly bound to proteins. (pnas.org)
  • Nevertheless, the mechanisms and regulation of heme iron reutilization are poorly understood. (pnas.org)
  • EC 1.14.99.3 ), which catabolizes cellular heme to biliverdin, carbon monoxide, and free iron, is represented by two isoforms, Hmox1 and Hmox2, encoded by separate genes. (pnas.org)
  • Iron is a crucial metal for normal development, being required for the production of heme, which is incorporated into cytochromes and hemoglobin. (biologists.org)
  • In erythroid cells, most iron is carried to the mitochondria, where it is incorporated with protoporphyrin to produce heme. (biologists.org)
  • Iron is found in food as inorganic iron and heme (iron complexed to protoporphyrin IX). (tomhsiung.com)
  • The typical diet consists of 90% inorganic and 10% heme iron, though diets in the industrial world can contain up to 50% heme iron from iron-rich meats. (tomhsiung.com)
  • The bioavailability of inorganic but not heme iron is influenced by multiple factors such as other dietary constituents, for example, ascorbic acid (enhanced) and phytates and polyphenols in cereals and plants (inhibited). (tomhsiung.com)
  • Heme iron is derived from hemoglobin, myoglobin, and other heme proteins in foods of animal origin, representing approximately 10% to 15% iron content in the typical Western diet, although heme-derived iron accounts for 2/3 of absorbed iron in meat-eating humans. (tomhsiung.com)
  • Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. (rsc.org)
  • We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. (rsc.org)
  • The protein in serum ferritin is considered benign, but it has lost ( i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. (rsc.org)
  • The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. (rsc.org)
  • In mammals (in contrast, for instance, to some functions in insects 1-4 ), ferritin is supposed to be a cellular means of storing iron, 5 not of transporting it, yet serum ferritin levels are widely measured as indicators of iron status. (rsc.org)
  • Taking a systems approach, we develop and summarise the view that "serum ferritin" actually originates from damaged cells (and thus reflects cellular damage), that it contains some iron but has lost or liberated most of its normal content, and that since the protein part of ferritin is assumed to be benign, that it is this (initially) free iron that correlates with and is causative of disease. (rsc.org)
  • At steady state, the serum ferritin level is a reasonably good reflection of total body iron stores. (tomhsiung.com)
  • From here, the iron is distributed to all body tissues. (drhui.com)
  • In contrast, with hereditary hemochromatosis the iron is placed directly onto transferrin and from there moves to the tissues. (drhui.com)
  • [ 3 ] In patients who receive numerous transfusions-notably those with thalassemia major , sickle cell disease , myelodysplastic syndrome , aplastic anemia , hemolytic anemia , and refractory sideroblastic anemias , who may become transfusion dependent-the excess iron from the transfused erythrocytes gradually accumulates in various tissues, causing morbidity and mortality. (medscape.com)
  • [ 9 ] It is this excessive iron that damages tissues. (medscape.com)
  • [ 12 ] Unlike ferritin, it does not circulate in blood but is deposited in tissues and is unavailable when cells need iron. (medscape.com)
  • Iron gradually builds up in certain cells and tissues over the course of the human life span. (lifeextension.com)
  • Too much iron accelerates mitochondrial decay and inflicts system-wide free radical damage to healthy tissues. (lifeextension.com)
  • Iron acquisition by developing erythroid cells is necessary to produce hemoglobin, which allows red blood cells to deliver oxygen to body tissues in exchange for carbon dioxide. (biologists.org)
  • In the ferrous state, iron acts as an electron donor, while in the ferric state it acts as an acceptor. (wikipedia.org)
  • While iron is abundant within the Earth's crust, ferrous (Fe 2+ ) iron spontaneously reacts with oxygen to form ferric (Fe 3+ ) iron, which is insoluble under physiological conditions [ 3 ]. (mdpi.com)
  • Iron undergoes dynamic redox coupling through reversible oxidation/reduction of ferrous iron (Fe 2+ ) and ferric iron (Fe 3+ ). (frontiersin.org)
  • Most of us are familiar with anemia, a common disorder in which a dearth of iron leads to pallid skin, dizziness, and shortness of breath. (psu.edu)
  • Although it's not as widespread as anemia, hemochromatosis occurs much more frequently than cystic fibrosis, often touted as the most common autosomal recessive disorder in humans. (psu.edu)
  • 22. The method of claim 21, wherein the human has a disorder associated with hemochromatosis, a β-thalassemia, or β-thalassemia intermedia. (patentsencyclopedia.com)
  • The Cth2 protein contains two Cx 8 Cx 5 Cx 3 H tandem zinc fingers (TZFs) that specifically bind to adenosine/uridine-rich elements within the 3′ untranslated region of many mRNAs to promote their degradation. (mdpi.com)
  • The Rnt1 RNase III exonuclease protects cells from excess iron by promoting the degradation of a subset of the Fe acquisition system when iron levels rise. (mdpi.com)
  • One potential class of post-transcriptional regulators are microRNAs- endogenous non-coding small RNAs that bind to complementary sites in the 3′UTR of target mRNAs and drive translational repression or mRNA degradation - . (prolekare.cz)
  • Ferristatin II promotes degradation of transferrin receptor-1 in vitro and in vivo. (labome.org)
  • 1999). Membrane-bound TfR includes a stalk region that places the TfR ectodomain about 30 Å above the cell surface (Fuchs et al. (nih.gov)
  • Ferrous iron importers ZIP8 and ZIP14 were localized in the ciPTEC plasma membrane. (springer.com)
  • Mitochondrial respiratory enzymes and plasma membrane enzymes such as sodium-potassium-adenosine triphosphatase (Na + +K + -ATPase) may be key targets of damage by non-transferrin-bound iron in cardiac myocytes. (springer.com)
  • Major role of integral membrane proteins, carriers, or transporters in drug transport is highlighted. (hindawi.com)
  • [ 10 ] This is the most toxic component due to high reduction-oxidation (redox) potential that generates oxygen-free radicals such as superoxide anion in the cells, which damages DNA, proteins, and membrane lipids in the cell. (medscape.com)
  • It is a homo-dimer consisting of two identical monomers joined by two disulfide bindings at cystein residues 89 and 92 in the extracellular domain just outside the cell membrane (Jing and Trowbridge 1987). (ifcc.org)
  • Can bind Fc portion of IgE to membrane. (brainscape.com)
  • It is a component of hemoglobin in red blood cells, binding the oxygen that the blood circulates throughout the body. (psu.edu)
  • Most of the iron requirement is provided through reutilization from existing total body stores of 3-4 g, of which about 70% is maintained within hemoglobin ( 4 ). (pnas.org)
  • Most iron (about 1800 mg) is present in hemoglobin. (tomhsiung.com)
  • Singh A. Hemoglobin control, ESA resistance, and regular low-dose IV iron therapy: a review of the evidence. (labome.org)
  • The diagnosis of thalassemia is made through studies such as bone marrow examination, hemoglobin electrophoresis, and iron count. (medscape.com)
  • 1998 ). In vitro studies have shown that iron exposure can result in decreased cellular viability in murine and human renal tubular epithelial cells (Sheerin et al. (springer.com)
  • [ 1 ] During normal physiology, the amount of iron absorbed from the small intestine (1-2 mg/d) is balanced by the iron lost through sloughing of intestinal mucosa and skin, as well as the small amounts excreted in the urine and bile. (medscape.com)
  • However, the mechanisms of tubular iron handling remain elusive. (springer.com)
  • [ 17 ] In a murine model of beta-thalassemia, the myocardial damage with increased interstitial fibrosis and remodelling appears to start before any significant myocardial iron deposits can be demonstrated, suggesting additional mechanisms of cardiac failure pathogenesis in thalassemia. (medscape.com)
  • Given the findings of studies to date, there appears to be significant evidence that intact iron transport mechanisms are critical to normal neural tube closure. (wikipedia.org)
  • While we now are aware of many strategies that the host has devised to sequester iron from invading microbes, there are as many if not more sophisticated mechanisms by which successful pathogens overcome nutritional immunity imposed by the host. (asmscience.org)
  • This review discusses some of the essential components of iron sequestration and scavenging mechanisms of the host, as well as representative Gram-negative and Gram-positive pathogens, and highlights recent advances in the field. (asmscience.org)
  • Normally in humans, about 1 mg of iron is absorbed by the intestine daily, and at the same time an approximately equal amount is eliminated from the body. (pnas.org)
  • Bartzokis' team showed that they could accurately measure iron levels in living humans' brains by using a highly specialized non-invasive form of magnetic resonance imaging (MRI). (lifeextension.com)
  • Several studies suggest that iron stores may influence the course of HIV infection in humans. (biomedcentral.com)
  • The interaction of primate transferrins with receptors on bacteria pathogenic to humans. (cdc.gov)
  • Iron is an essential micronutrient for both microbes and humans alike. (asmscience.org)