metallothionein and Menkes-Kinky-Hair-Syndrome

The transition metal copper (Cu) is an essential trace element for all biota. Its redox properties bestow Cu with capabilities that are simultaneously essential and potentially damaging to the cell. Free Cu is virtually absent in the cell. The descriptions of the structural and functional organization of the metallothioneins, Cu-chaperones and P-type ATPases as well as of the mechanisms that regulate their distribution and functioning in the cell have enormously advanced our understanding of the Cu homeostasis and metabolism in the last decade. Cu is stored by metallothioneins and distributed by specialized chaperones to specific cell targets that make use of its redox properties. Transfer of Cu to newly synthesized cuproenzymes and Cu disposal is performed by the individual or concerted actions of the P-type ATPases ATP7A and ATP7B expressed in tissues. In mammalians liver is the major captor, distributor and excreter of Cu. Mutations in the P-type ATPases that interfere with their functioning and traffic are cause of the life-threatening Wilson (ATP7B) and Menkes (ATP7A) diseases.

Topics: Adenosine Triphosphatases; Animals; Cation Transport Proteins; Copper; Copper-Transporting ATPases; Diet; Electron Transport Complex IV; Glutathione; Hepatolenticular Degeneration; Homeostasis; Humans; Liver; Menkes Kinky Hair Syndrome; Metallothionein; Models, Biological; Molecular Chaperones; Mutation; Oxidation-Reduction; Superoxide Dismutase; Superoxide Dismutase-1

Metallothioneins (MTs) are ubiquitous metal-binding proteins that have been highly conserved throughout evolution. Although their physiological function is not completely understood, they are involved in diverse processes including metal homeostasis and detoxification, the oxidative stress response, inflammation, and cell proliferation. Te human MT gene family consists of at least 18 isoforms, containing pseudogenes as well as genes encoding functional proteins. Most of the MT isoforms can be induced by a wide variety of substances, such as metals, cytokines, and hormones. Different cell types express discrete MT isoforms, which reflects the specifically adapted functions of MTs and a divergence in their regulation. Te aberrant expression of MTs has been described in a number of diseases, including Crohn's disease, cancer, Alzheimer's disease, amyotrophic lateral sclerosis, Menkes disease, and Wilson's disease. Therefore, a thorough understanding of MT gene regulation is imperative. To date, the transcriptional regulation of MTs has primarily been studied in mice. While only four murine MT isoforms exist, the homology between murine and human MTs allows for the evaluation of the regulatory regions in their respective promoters. Here, we review the aberrant expression of MTs in human diseases and the mechanisms that regulate MT1 expression based on an in silico evaluation of transcription factor binding sites.

Topics: Alzheimer Disease; Animals; Crohn Disease; Gene Expression Regulation; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Neoplasms; Phylogeny; Promoter Regions, Genetic

The transition metal copper is an essential trace element involved in many enzymatic processes that require redox-chemistry. The redox-activity of copper is potentially harmful. Severe imbalance of copper homeostasis can occur with some hereditary disorders of copper metabolism. Copper is acquired from the diet by intestinal absorption and is subsequently distributed throughout the body. The regulation of intestinal copper absorption to maintain whole-body copper homeostasis is currently poorly understood. This review evaluates novel findings regarding the molecular mechanism of intestinal copper uptake. The role of recently identified transporters in enterocyte copper uptake and excretion into the portal circulation is described, and the regulation of dietary copper uptake during physiological and pathophysiological conditions is discussed.

Topics: Biological Transport; Ceruloplasmin; Copper; Enterocytes; Hepatolenticular Degeneration; Homeostasis; Humans; Intestinal Absorption; Menkes Kinky Hair Syndrome; Metallothionein; Oxidation-Reduction; Trace Elements

Topics: Adolescent; Animals; Child; Child, Preschool; Cobalt; Copper; Female; Humans; Infant; Intestinal Mucosa; Iron; Iron Deficiencies; Iron Overload; Male; Malnutrition; Menkes Kinky Hair Syndrome; Metallothionein; Nutrition Policy; Nutritional Requirements; Pregnancy; Selenium; Zinc

Topics: Animals; Ascorbic Acid; Biological Transport, Active; Ceruloplasmin; Copper; Glutathione; Histidine; Intestines; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Rats; Serum Albumin

Early research on metallothionein centered on aspects related to a detoxification role. As our understanding of the complex endocrine control that regulates metallothionein gene expression increases, a wider appreciation of a functional role(s) is emerging. Medical implications of control of metallothionein turnover include diagnosis of specific diseases and regulation of its expression as a host defense component.

Topics: Binding Sites; Biological Transport; Carrier Proteins; Free Radicals; Gene Expression Regulation; Hormones; Humans; Inactivation, Metabolic; Intestinal Absorption; Lysosomes; Menkes Kinky Hair Syndrome; Metallothionein; Metals; Protein Conformation

Topics: Acrodermatitis; Cadmium; Chromium; Copper; Disease; Disease Models, Animal; Growth; Hemochromatosis; Hepatolenticular Degeneration; Humans; Iron; Magnesium; Male; Menkes Kinky Hair Syndrome; Metallothionein; Milk, Human; Nucleic Acids; Selenium; Testis; Trace Elements; Zinc

Metallothioneins are a family of ubiquitous, cysteine rich proteins, whose amino acidic and genomic sequences have been highly conserved during evolution. MT synthesis is induced by heavy metals, glucocorticoids and a bacterial lipopolysaccharide in vivo and in vitro. MT forms stable complexes with heavy metals. One MTIIA gene, four MTI class genes and five pseudogenes have been isolated in humans. The cluster of MT genes is located on chromosome 16. The cloned, transfected genes retain metal inducibility. The first 150 bp of the 5' flanking region of mouse and human MT genes are essential for transcription and metal regulation. Two control regions have been identified. The distal region, between -151 and -78 is essential for efficient transcription and binding of cellular factor(s) which regulates MT gene expression. In Menkes' disease, a lethal X-linked recessive disorder, copper accumulates intracellularly bound to MT. Low doses of copper induce MT synthesis in Menkes' fibroblasts, but not in normal controls. Transfection experiments using the mouse MTI promoter fused to CAT show that the effect of copper in MT transcription is in trans. Menkes' cells are more sensitive to copper than normal controls and respond to copper poisoning by synthesizing two heat-shock like proteins. A mutation affecting copper transport or metabolism is discussed.

Topics: Animals; Brain Diseases, Metabolic; Cadmium; Cells, Cultured; Copper; Disease Models, Animal; Gene Expression Regulation; Humans; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Promoter Regions, Genetic; Structure-Activity Relationship

A hypothesis is proposed admitting the participation of apometallothioneines (AMT) as a common link in the etiopathogenesis of hypertonic disease (HD) and some diseases with polygene heredity. The preconditions of the hypothesis are discussed (role of genetic disposition, external factors as salt, stress, tobacco smoking, alcohol, microelements--V and Cd and glucocorticoids in the origination of arterial hypertension). AMT homeostasis is discussed as well as the possible connection with the metabolism of Zn and Cu and Cu in organism. The chelating capacity of AMT makes it a potential regulatory protein, associated with the activity of Zn- and Cu-dependent enzymes and metalloenzymes. The mosaicism of pathology is explained with the genetic polymorphism of those enzymes (D beta H, MAO, etc), regardless of the common etiopathogenetic link. Some schemes are presented illustrating the hypothesis. The tendencies of the future studies are outlined in searching of direct proofs of the hypothesis.

Topics: Adrenal Cortex; Animals; Apoproteins; Blood Pressure; Copper; Disease Models, Animal; Disease Susceptibility; Genes; Genetic Diseases, Inborn; Glucocorticoids; Homeostasis; Humans; Hypertension; Menkes Kinky Hair Syndrome; Metallothionein; Terminology as Topic; Zinc

Various inherited disorders of copper metabolism in man and animals are reviewed. Emphasis is placed on the use of cultured cells from mutants to determine the primary molecular defects and to acquire basic knowledge of normal copper metabolism. This allows better diagnostic tests and possible treatment of the disorders. Menkes' disease in humans and mottled mouse mutants are discussed in detail, as they illustrate these approaches.

Topics: Animals; Brain Diseases, Metabolic; Cells, Cultured; Copper; Disease Models, Animal; Dogs; Electron Transport Complex IV; Female; Fibroblasts; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Mice, Mutant Strains; Mice, Quaking; Pregnancy; Protein-Lysine 6-Oxidase

Topics: Absorption; Acrodermatitis; Animals; Biological Availability; Biological Transport, Active; Blood Proteins; Copper; Enzymes; Hepatolenticular Degeneration; Humans; Ligands; Menkes Kinky Hair Syndrome; Metallothionein; Zinc

Topics: Animals; Brain Diseases, Metabolic; Copper; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; Oxidoreductases

We have developed an easy and specific enzyme-linked immunoassay (ELISA) for the simultaneous determination of serum metallothinein-1 (MT-1) and 2 (MT-2) in both humans and experimental animals. A competitive ELISA was established using a specific polyclonal antibody against rat MT-2. The antibody used for this ELISA had exhibited the same cross-reactivity with MT in humans and experimental animals. The NH2 terminal peptide of MT containing acetylated methionine was shown to be the epitope of this antibody. The reactivity of this ELISA system with the liver, kidney and brain in MT1/2 knock-out mice was significantly low, but was normal in an MT-3 knock-out mouse. The lowest detection limit of this ELISA was 0.6ng/ml and the spiked MT-1was fully recovered from the plasma. We investigated the normal range of MT1/2 (25-75%tile) in 200 healthy human serum and found it to be 27-48ng/ml, and this was compared with the serum levels in various liver diseases. The serum MT1/2 levels in chronic hepatitis C (HCV) patients were significantly lower than healthy controls and also other liver diseases. In the chronic hepatitis cases, the MT1/I2 levels increased gradually, followed by the progression of the disease to liver cirrhosis and hepatocellular carcinoma. In particular, we found significantly elevated MT1/2 plasma levels in Wilson's disease patients, levels which were very similar to those in the Long-Evans Cinnamon (LEC) rat (model animal of Wilson's disease). Furthermore, a significantly elevated MT1/2 level was found in patients with Menkes disease, an inborn error of copper metabolism such as Wilson's disease.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Female; Hepatolenticular Degeneration; Humans; Male; Menkes Kinky Hair Syndrome; Metallothionein; Metallothionein 3; Mice, Knockout; Middle Aged; Young Adult

Menkes disease is an X-linked disorder of copper metabolism. Excess amounts of copper in the kidney of Macular mice, a model for this disease, were found as copper-metallothionein (Cu-MT) from kidney of the mice. Histochemical studies of Cu-MT based on its autofluorescent emission properties showed that the protein was predominant in the proximal convoluted tubule (PCT) cells of the cortex. PCT cells are known to be the primary site of the nephrotoxicity caused by heavy metals. MT mRNA was also observed in the cortex, indicating that the protein was biosynthesized in this region. On the basis of these results, we suggest that biosynthesis and degradation of Cu-MT occur repeatedly in the PCT cells of the cortex. We also compared the histochemical localization of Cu-MT in Macular mice and Long-Evans cinnamon rats, a model for Wilson's disease. The significance of this comparison is discussed.

Topics: Acid Phosphatase; Animals; Carrier Proteins; Copper; Disease Models, Animal; Histocytochemistry; Injections, Subcutaneous; Kidney; Kidney Cortex; Kidney Tubules, Proximal; Lysosomes; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Inbred C3H; Mice, Inbred Strains; Rats; RNA, Messenger

Human Menkes disease and the murine Mottled phenotype are X-linked diseases that result from copper deficiency due to mutations in a copper-effluxing ATPase, designated ATP7A. Male mice with the Mottled-Brindled allele (Mo-brJ) accumulate copper in the intestine, fail to export copper to peripheral organs and die a few weeks after birth. Much of the intestinal copper is bound by metallothionein (MT). To determine the function of MT in the presence of Atp7a deficiency, we crossed Mo-brJ females with males that bear a targeted disruption of the Mt1 and Mt2 genes (Mt-/-). On an Mt -/- background, most Mo-brJ males as well as heterozygous Mo-brJ females die before embryonic day 11. The lethality in Mo-brJ females can be explained by preferential inactivation of the paternal X chromosome in extraembryonic tissues and resultant copper toxicity in the absence of MT. In support of this hypothesis, cell lines derived from Mt -/-, Mo-brJ embryos are very sensitive to copper toxicity.

Topics: Adenosine Triphosphatases; Animals; Base Sequence; Carrier Proteins; Cation Transport Proteins; Cell Survival; Cells, Cultured; Copper; Copper-Transporting ATPases; Crosses, Genetic; Culture Media; Disease Models, Animal; Embryo, Mammalian; Female; Fetal Death; Intestinal Mucosa; Intestines; Liver; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Inbred Strains; Molecular Sequence Data; Recombinant Fusion Proteins; Tissue Distribution; X Chromosome

Systematic studies have been undertaken to compare the effects of cell lysis and chromatography conditions on the observed distribution of Cu amongst Cu-binding proteins in cultured cells. The variables included rate of centrifugation, presence or absence of non-ionic detergent, and presence or absence of dithiothreitol. The application of an improved FPLC gel filtration system has permitted us to examine the effects of the addition of exogenous metallothionein (MT) to cell extracts. When the cell extract contains low levels of endogenous MT, the addition of MT in the presence of dithiothreitol causes a shift of copper to the MT peak. High levels of MT can therefore remove copper from other Cu-binding ligands during cell homogenization, hence producing artifactual Cu distribution results. The use of an anaerobic buffer system has greatly reduced the observed level of Cu exchange, and has allowed comparison of Cu distribution in normal cells and cells from patients with Menkes' disease.

Topics: Animals; Cell Fractionation; Cell Line; Chromatography, Gel; Copper; Humans; Ion Transport; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Subcellular Fractions

The copper concentration was investigated in the cultured astrocytes from macular mice, an animal model of Menkes disease. An excessive amount of copper was accumulated in the astrocytes as copper-metallothionein. These results show that the underlying genetic defect of the macular mouse is expressed in the astrocytes. A similar situation may exist in Menkes disease and cause a failure of copper transport to neurones.

Topics: Animals; Astrocytes; Brain; Cells, Cultured; Copper; Gene Expression; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains

These studies were designed to determine if macular mutant mouse, which is a proposed animal model of Menkes' kinky-hair disease, is sensitive to the acute toxic effect of Cu as compared to normal and heterozygote mice. Single sc injection of Cu were administered to 6- to 8-day-old mice, and mortalities were recorded for 30 days. The copper treatment at high doses (12 to 25 mg Cu/kg) was very toxic to mutant mice as compared to normal mice, and almost all mutant mice died within 10 days after injection. The effect of Cu toxicity on heterozygote mice was intermediate. The LD50 values 3 days after injection of Cu were 29.5 mg Cu/kg for normal mice, 23.5 mg Cu/kg for heterozygote mice, and 15.5 mg Cu/kg for mutant mice. In Cu-injected mutant mice (11 and 18 mg Cu/kg), significant elevations in serum aspartate aminotransferase and lactate dehydrogenase activity occurred as compared to Cu-injected normal and heterozygote mice. However, no significant elevations in serum creatinine and urea nitrogen contents in Cu-injected mutant were observed as compared to normal and heterozygote mouse. No significant differences in hepatic metallothionein(MT) and MT-1 mRNA, and serum ceruloplasmin oxidase activity levels were observed between Cu-injected normal and mutant mouse. These results indicated that macular mutant mice was sensitive to the acute toxic or hepatotoxic effects of Cu as compared to normal and heterozygote mice.

Topics: Animals; Aspartate Aminotransferases; Blood Urea Nitrogen; Ceruloplasmin; Copper; Disease Models, Animal; Heterozygote; L-Lactate Dehydrogenase; Lethal Dose 50; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; Tissue Distribution

Levels of metallothionein-1 (MT-1) messenger RNA (mRNA) in various tissues from normal and macular mutant mice at different stages of development (17 days of gestation, 1-, 3-, 7- and 14-day-old) were determined by Northern blot analysis. Renal MT-1 mRNA levels in mutant mice were slightly elevated at 3 stages compared to normal mice, with the exception of mutant fetus and 3-day-old mutant mice. Intestinal MT-1 mRNA levels in mutant mice were elevated at 3 stages compared to normal mice with the exception of mutant fetus and 3-day-old mutant mice. Hepatic MT-1 mRNA levels in mutant fetus and 1-day-old mutant mice were approximately the same compared to normal mice. In 3- and 7-day-old mutant mice, hepatic MT-1 mRNA levels were depressed and in 14-day-old mutant mice, they were increased compared to normal mice. Brain MT-1 mRNA could not be detected in normal and mutant mice at the 4 stages with the exception of 14-day-old mice. MT-1 mRNA in 14-day-old mice was detected and the level of that in mutant mice was slightly elevated compared to normal mice. After injection of Cu, MT-1 mRNA levels in kidney, liver and intestine were determined. The injection of Cu increased the level of MT-1 mRNA in the tissues of normal and mutant mice compared to control (saline-injected) mice. Significant differences in MT-1 mRNA levels in the tissues of both Cu-injected mice were not observed.

Topics: Animals; Brain Chemistry; Copper; Disease Models, Animal; Intestines; Kidney; Liver; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; RNA, Messenger; Zinc

Menkes' disease is an inherited disturbance of copper metabolism. Addition of copper to the medium of cultured fibroblasts and lymphoblasts from patients with Menkes' disease results in an increased induction of metallothionein. We investigated the metallothionein induction in response to copper and zinc in muscle cells (myoblasts and myotubes). Metallothionein synthesis was analyzed by gel electrophoresis of labeled proteins and metallothionein synthesis in muscle cells was compared with the synthesis in fibroblasts. The induction by copper was higher both in muscle cells and in fibroblasts from the Menkes' patient compared to the control cells. Hybrid myotubes obtained by fusion of control myoblasts and Menkes' myoblasts render a system in which complementation can be studied. Metallothionein synthesis in hybrid myotubes occurred at a level intermediate between the synthesis in Menkes' and control myotubes. The abnormal accumulation of copper-induced metallothionein was only partially corrected by fusion with normal cells. Metallothionein induction by zinc was similar in Menkes' and control fibroblasts. Combination of copper and zinc yielded no differences in additional metallothionein synthesis for Menkes' cells and control fibroblasts. Therefore, metallothionein induction in Menkes' disease can primarily be accounted for by copper rather than by zinc.

Topics: Cell Fusion; Cells, Cultured; Copper; Gene Expression Regulation; Hybrid Cells; Menkes Kinky Hair Syndrome; Metallothionein; Muscle Proteins; Muscles; Stimulation, Chemical; Zinc

We present 64Cu uptake studies in cultured muscle cells from a one-year-old patient with Menkes' disease. The cultured muscle cells from the patient showed a five-fold higher 64Cu uptake than control muscle cells. Copper uptake in muscle cells was of the same magnitude as that found in fibroblasts from the patient and also from other Menkes' patients. The copper content of a muscle biopsy from the patient was twice that of a control biopsy. The enhanced uptake is probably copper specific, since zinc uptake was unaltered in both muscle cells and fibroblasts from the patient. Cytochrome c oxidase in the muscle of the patient was reduced to one-third of the value for controls, which is in agreement with the hypothesis that in Menkes' disease copper accumulates in a biologically non-active form. However, in cultured muscle cells and fibroblasts from the patient the cytochrome c oxidase activity was in the normal range, probably because of the relatively large amount of copper already available in the culture medium.

Topics: Brain Diseases, Metabolic; Cells, Cultured; Copper Radioisotopes; Electron Transport Complex IV; Fibroblasts; Humans; Infant; Menkes Kinky Hair Syndrome; Metallothionein; Muscles; Zinc Radioisotopes

Fibroblasts from the brindled mouse model of Menkes disease are known to accumulate excess copper. Most of the copper in the cytosol of these fibroblasts is bound to metallothionein (MT), which is elevated in Menkes or brindled mouse fibroblasts. Copper accumulation by normal fibroblasts containing excess MT was examined to determine if the excess copper accumulation phenotype was secondary to excess MT or associated with the primary defect in fibroblasts from the brindled mice. MT was induced in normal fibroblasts by copper, zinc or dexamethasone to levels comparable with those in brindled mice fibroblasts, as determined by radioimmunoassays. Normal fibroblasts containing excess MT accumulate copper normally, i.e. they do not exhibit the excess copper accumulation phenotype. Consistent with this result, copper efflux from normal fibroblasts containing excess MT was also normal. The data suggest that one function of the protein associated with the primary defect is to help determine how much copper is taken up and retained by fibroblasts and other cell types exhibiting the excess copper phenotype in Menkes disease. The capacity of this protein is apparently exceeded in normal fibroblasts if serum or albumin is not present extracellularly to limit total copper uptake. Consistent with a defect in an intracellular protein, the kinetics of copper transport by brindled mice fibroblasts were found to be normal.

Topics: Animals; Biological Transport; Brain Diseases, Metabolic; Cells, Cultured; Copper; Disease Models, Animal; Female; Fibroblasts; Kinetics; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Reference Values; Skin

The proteins that bind copper when it first enters cells are likely to play roles in its intracellular distribution and utilization. When hepatocytes were incubated with 64Cu(II), the time-dependence of the subcellular distribution of 64Cu was consistent with one or more cytosolic proteins distributing copper to the mitochondrial and nuclear fractions. Cytosolic copper was reproducibly distributed among four protein fractions from Sephadex G-150 columns at the earliest time (1 min) and at the lowest concentration used [2 microM-64Cu(II)] with both rat and mouse hepatocytes. Copper binding to proteins in these functions was sensitive to copper metabolic status. Hepatocytes from nutritionally copper-deficient rats or neonatal (9-30 days old) developing rats showed an inverse correlation between copper binding to metallothionein and copper binding to proteins in fraction I (approximately 88 kDa apparent) and fraction II (approximately 38 kDa apparent). The distribution of cytosolic 64Cu from the brindled-mouse model of Menkes disease indicated decreased binding by a protein in fraction I. Brindled-mouse hepatocytes also contain decreased levels of a approximately 55 kDa protein or subunit, which most likely represents a liver-specific secondary response to the primary defect. The results are consistent with one or more copper-binding proteins in fractions I and II having significant functions in intracellular copper metabolism.

Topics: Animals; Carrier Proteins; Copper; Cytosol; In Vitro Techniques; Kinetics; Liver; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Nutritional Status; Rats; Rats, Inbred Strains; Zinc

Topics: Brain Diseases, Metabolic; Carrier Proteins; Copper; Genetic Linkage; Humans; Menkes Kinky Hair Syndrome; Metallothionein; X Chromosome

Menkes' kinky hair disease, a lethal X-linked recessive trait, is characterized by abnormal copper accumulation in several non-hepatic tissues. The level of many copper enzymes is severely reduced, leading to damage of the connective and nervous tissues of the patients. Cultured skin fibroblasts from Menkes' patients retain more copper then normal controls, and the excess metal is bound to metallothionein. Low doses of copper in the media induce MT gene transcription in Menkes' but not in normal cells. Transfection experiments using a plasmid containing the mouse MT-I promoter fused to the enzyme chloramphenicol acetyl transferase show that the activation of the mMTI promoter is in trans. Two other effects are observed in Menkes' cells: (a) two heat-shock like proteins are synthesized in response to low doses of copper in the growth medium, and (b) Menkes' cells are more sensitive then normal fibroblasts to copper toxicity. Our interpretation of these results supports a model for a defect in one or more steps in copper metabolism or transport.

Topics: Brain Diseases, Metabolic; Cells, Cultured; Copper; DNA, Recombinant; Dose-Response Relationship, Drug; Fibroblasts; Gene Expression Regulation; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Promoter Regions, Genetic; Protein Biosynthesis; RNA, Messenger; Transcription, Genetic; Transfection; Zinc

The tissue copper and metallothionein-Cu (MT-Cu) content of kidney and liver were measured in mutant (hemizygous macular male and homozygous macular female), heterozygous macular female and normal mouse. The tissue copper and MT-Cu contents in kidneys from 7-8 day mutants and heterozygotes were significantly greater than those of the normal kidney. Marked elevations in kidney copper and MT-Cu contents were also observed in the 8-9 week mutant (which achieved long-term survival with a single dose of subcutaneous copper administered at day 7) and in the heterozygote. The L-[35S]cystine incorporation experiments also revealed an abnormal synthesis of renal MT in the 8-9 week mutant and in the heterozygote. In contrast to kidney Cu levels, the tissue copper and MT-Cu contents of 7-8 day normal livers were extremely high, whereas the tissue copper and MT-Cu contents of mutant and heterozygote livers were extremely low. The tissue copper contents of livers of 8-9 week mutants and heterozygotes were slightly low compared to normal, and the MT-Cu contents of livers of the 8-9 week mouse were extremely low in all groups. In contrast to the changes in copper content, the changes in tissue zinc and MT-Zn contents in kidney and liver were slight in the 7-8 day and 8-9 week mouse.

Topics: Animals; Brain Diseases, Metabolic; Copper; Cytosol; Disease Models, Animal; Female; Genetic Carrier Screening; Kidney; Liver; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; Spectrophotometry, Atomic; Zinc

A study was carried out on the uptake of copper, zinc, or cadmium ions and their induction of metallothionein synthesis in Menkes' and normal lymphoblastoid cells. The main difference between Menkes' and normal cells in the uptake of these metal ions was an increased uptake of copper ions in Menkes' cells at a low concentration of CuCl2 (2.1 microM). The CuCl2 concentration necessary to induce metallothionein synthesis in Menkes' cells was 50 microM, whereas that in normal cells was about 200 microM. The levels of zinc or cadmium ions needed to induce metallothionein in Menkes' cells were similar to those in normal cells. At least four isomers of metallothionein were induced by copper, zinc, and cadmium ions in both types of cells. Metallothionein synthesis in Menkes' and normal cells was induced when the amounts of intracellular copper reached a threshold level of approximately 0.2 nmol/10(6) cells, and the rate of metallothionein synthesis in these cells was increased as a function of the amounts of intracellular copper (0.2-1.7 nmol/10(6) cells). These results indicate that the induction of metallothionein synthesis in lymphoblastoid cells is controlled by the level of intracellular copper, suggesting that the major defect in Menkes' cells is not due to the abnormal regulation of metallothionein synthesis but to an alteration of the copper metabolism in cells by which the levels of intracellular copper become larger than those in normal cells and just lower than the threshold level for induction of metallothionein synthesis.

Topics: B-Lymphocytes; Biological Transport; Brain Diseases, Metabolic; Cadmium; Cell Line; Copper; Female; Humans; Kinetics; Menkes Kinky Hair Syndrome; Metallothionein; Reference Values; Zinc

Menkes kinky hair syndrome is an X-linked neurodegenerative disorder, causing tissue-specific increases in copper and metallothionein content. A mouse model is provided by hemizygotes for mutant alleles at the X-linked mottled locus. Herein we test the possibility that the primary defect in both species is in metallothionein gene regulation. We show that metallothionein-I messenger RNA (mRNA) (mouse) and metallothionein-II mRNA (human) are elevated in mutant fibroblasts. However, comparable dose-response curves in mutant and control cells are generated when mouse metallothionein-I mRNA concentrations are measured in cells exposed to varying concentrations of cadmium or copper (metallothionein inducers). Furthermore, when mutant and control cells are grown to achieve overlapping intracellular copper concentrations in the two cell types, metallothionein-I (mouse) and metallothionein-II (human) mRNA levels are proportional to the intracellular copper concentrations. Finally, in paired determinations in blotchy hemizygote and littermate kidneys containing comparable copper levels, metallothionein-I mRNA contents are very similar. The observations suggest that elevated intracellular copper in these mutants induces metallothionein synthesis by normal regulatory mechanisms.

Topics: Alleles; Animals; Brain Diseases, Metabolic; Cadmium; Copper; Female; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; RNA, Messenger

The characteristic feature of Menkes' disease is a maldistribution of bodily copper; decreased copper levels are present in the serum, brain, and liver, whereas excess levels are present in gut, kidney, and most other nonhepatic tissues. Using cultured fibroblasts, we have shown that low extracellular copper concentrations induce synthesis of metallothionein, a copper-binding protein, in Menkes' cells but not in normal cells. This is due to a defect in a diffusable regulatory factor that is probably involved in copper metabolism. To further understand the role of the defective factor in transcription, assays have been developed to study the metal-dependent binding of nuclear proteins to metallothionein gene control sequences.

Topics: Animals; Brain Diseases, Metabolic; Cells, Cultured; Copper; Gene Expression Regulation; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Transcription Factors; Transcription, Genetic

Menkes' kinky-hair syndrome is an X-linked recessive neurodegenerative and connective-tissue disorder, with decreased serum copper and ceruloplasmin-copper oxidase concentrations and tissue-specific increases in copper content. Clinical manifestations can be related to relative copper deficiency and reduced activity of cuproenzymes in multiple organs. An animal model is provided by mice hemizygous for mutant alleles, such as the blotchy allele, at the X-linked mottled locus. This locus may be homologous in mouse and man. The basic defect is unknown but has been thought to reside in the regulation of the function or synthesis of metallothioneins. In the blotchy mouse and in cultured skin fibroblasts derived therefrom, we showed that the mutation specifically affects the metabolism of copper and not other trace metals. Excessive accumulation and abnormal (reduced) exit kinetics were demonstrated for copper but not for the related trace metals cadmium and zinc. While metallothionein-I messenger RNA (mRNA) concentrations were elevated in blotchy fibroblasts, the elevations in metallothionein-I mRNA in response to metallothionein inducers (cadmium, copper) were similar in blotchy and control cells. Further, metallothionein-I mRNA levels were indistinguishable in mutant and control fibroblasts containing equivalent intracellular copper concentrations. Finally, metallothionein-I mRNA content was not elevated in blotchy kidneys at early developmental stages, before storage of excessive copper. The aggregate data suggest that the basic defect in the blotchy mouse--and, by analogy, in Menkes' syndrome--does not reside in defective modulation of metallothionein function and does not cause abnormal regulation of metallothionein synthesis.

Topics: Animals; Brain Diseases, Metabolic; Cells, Cultured; Copper; Female; Genetic Linkage; Male; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Mice, Mutant Strains; Mutation; RNA, Messenger; Skin; X Chromosome

Cultured skin fibroblasts from patients with Menkes disease and Wilson disease were analyzed as to their sensitivities to copper and cadmium by means of a colony-forming ability and cell growth study. All the Menkes strains exhibited about 3-fold higher levels of resistance to cadmium, whereas the cytotoxicity of copper did not differ among the Menkes, Wilson and normal fibroblast strains. The resistance to cadmium of Menkes skin fibroblasts may provide a diagnostic marker of Menkes disease and useful or valuable model for the understanding of detoxification system against heavy metals.

Topics: Brain Diseases, Metabolic; Cadmium; Cadmium Chloride; Cell Division; Colony-Forming Units Assay; Copper; Drug Resistance; Fibroblasts; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Osmolar Concentration; Skin

Topics: Angiogenesis Inducing Agents; Animals; Ceruloplasmin; Copper; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Neoplasms; Neovascularization, Pathologic

Menkes' disease, an inherited disorder of copper metabolism, is characterized by the accumulation of excess copper-metallothionein in certain tissues and cell types. Using cultured fibroblasts, we show that this is due to the ability of low concentrations of copper to induce metallothionein mRNA synthesis in Menkes' but not normal cells. We also show that copper, which is unusually toxic to Menkes' cells, induces the synthesis of 84 kd and 68 kd polypeptides tentatively identified as heat shock proteins. Transfection experiments with a cloned metallothionein fusion gene show that this is due to a defect in a diffusible factor involved in either metallothionein gene transcriptional regulation or copper metabolism.

Topics: Brain Diseases, Metabolic; Copper; Gene Expression Regulation; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Models, Biological; Mutation; RNA, Messenger; Transcription, Genetic

Topics: Animals; Brain Diseases, Metabolic; Copper; Humans; Infant; Infant, Newborn; Menkes Kinky Hair Syndrome; Metallothionein; Mice

Copper concentration, intracellular copper distribution, and inducibility of metallothionein-like metal-binding protein (MLP) by copper or cadmium addition to culture medium were compared among three types of skin fibroblasts derived from patients with Menkes' disease and Wilson's disease, both exhibiting genetic defects of copper metabolism, and from normal subjects (control). Skin fibroblasts were cultivated in Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and antibiotics in 5% CO2 at 37 degrees C. Cells were harvested with rubber-policeman, washed twice with phosphate-buffered saline, pH 7.2, suspended in deionized water, and homogenized. The homogenate from each cell type was used to determine the concentration of copper by atomic absorption spectrophotometry employing graphite-rod atomizer after lyophilization, ashing in HNO3, and coprecipitation with zirconium. Intracellular copper concentration was elevated in Menkes' cells (420 ng Cu/mg of protein) and Wilson's cells (217 ng Cu/mg of protein) than in control cells (90.0 ng Cu/mg of protein), although one of four Wilson's strains showed normal copper level (70.5 ng Cu/mg of protein). Cytosol copper concentration was 5.8-fold higher in Menkes' cells but only 1.3-fold in Wilson's cells than in control cells, and cytosol copper accounted for only 35% of total intracellular copper in Wilson's cells as compared with 68% and 52% in Menkes' and control cells, respectively. These suggest that accumulated copper in each cell type is differently distributed within cells; in Menkes' cells exclusively into cytosol, but in Wilson's cells into particulates rather than cytosol. Elution profiles from Sephadex G-75 columns indicated that most of copper had bound to MLP in Menkes' cells, though no Cu-MLP was detectable in Wilson's or control cells under these experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Brain Diseases, Metabolic; Carrier Proteins; Cell Line; Cells, Cultured; Child; Chromatography, Gel; Copper; Female; Fibroblasts; Hepatolenticular Degeneration; Humans; Infant; Male; Menkes Kinky Hair Syndrome; Metallothionein; Skin

Menkes' kinky hair syndrome is a lethal X-linked disorder marked by tissue-specific increases in copper content. An animal model of kinky hair syndrome is provided by mice mutant at the X-linked mottled locus. The basic defect is unknown. In order to discriminate among potential etiologies, we asked whether the expression of the mottled mutation causes abnormalities in the metabolism of trace metals other than copper in hemizygous mottled (blotchy) cultured skin fibroblasts, and whether we can differentiate mutant and normal cells according to their response to metal inducers of metallothionein. Blotchy fibroblasts accumulated up to 12 times more 64Cu than control (littermate) cells, over time and over a range of 64Cu concentrations. A saturable high affinity component to 64Cu accumulation over a fixed time interval was revealed in these studies. While 64Cu uptake kinetics were indistinguishable in mutant and control cells, the patterns of 64Cu exit differed. In both cell types, the rate of release of a rapidly exchangeable fraction of newly acquired 64Cu was similar. However, in mutant cells, a larger fraction of recently accumulated 64Cu is retained. In contrast to the results for 64Cu, accumulation and exit of 65Zn and 109Cd were not distinguishable in mutants and controls. With exposure to either a strong (cadmium) or weaker (zinc) inducer of metallothionein, 64Cu accumulation was increased in normal cells, while there was no change from the already elevated level of 64Cu accumulation in blotchy cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cadmium; Cells, Cultured; Copper; Fibroblasts; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Metals; Mice; Mice, Mutant Strains; Skin; Time Factors; Zinc

Human metallothioneins are encoded by a complex multigene family. The chromosomal location of these genes has been determined by gel transfer hybridization analysis of the DNA from human-rodent cell hybrids. Chromosome 16 contains a cluster of metallothionein sequences, including two functional metallothionein I genes and a functional metallothionein II gene. The remaining sequences, including a processed pseudogene, are dispersed to at least four other autosomes. The absence of metallothionein sequences from the X chromosome indicates that Menkes' disease, an X-linked disorder of copper metabolism, affects metallothionein expression by a trans-acting mechanism.

Topics: Animals; Brain Diseases, Metabolic; Chromosome Mapping; Chromosomes, Human, 16-18; Copper; Cricetinae; Cricetulus; Humans; Hybrid Cells; Menkes Kinky Hair Syndrome; Metallothionein; Mice

Cultured fibroblasts of 13 patients with the Menkes syndrome and two with a new subtype (type IX) of the Ehlers-Danlos syndrome (E-D IX patients) showed many very similar abnormalities in their copper and collagen metabolism. Both cell types had markedly increased copper concentrations and 64Cu incorporation, and this cation accumulated in metallothionein or a metallothionein-like protein, as previously established for Menkes cells. Histochemical staining indicated that copper was distributed diffusely throughout the cytoplasm in both cell types, this location being consistent with the accumulation in metallothionein. Both fibroblast types also had markedly low lysyl oxidase activity and distinctly increased extractability of newly synthesized collagen, whereas no abnormalities were present in cell viability, duplication rate, prolyl 4-hydroxylase activity, or collagen synthesis rate. A high negative correlation (P less than 0.001) was found in the pooled group of Menkes and E-D IX cells between cellular copper concentration (r = 0.804) or 64Cu incorporation (r = 0.863) and the logarithm of lysyl oxidase activity. There was also a high positive correlation (P less than 0.001) between cellular copper concentration and incorporation (r = 0.869). One of the two E-D IX patients was also shown to have similar changes in lysyl oxidase activity and collagen extractability in the skin biopsy specimen, suggesting that the abnormalities observed in cultured cells are similar to those present in vivo. The only distinct abnormality found in the cells of the parents of the E-D IX patients was an increased 64Cu incorporation in those of the mother, this finding being consistent with X-linked inheritance of the disorder.

Topics: Brain Diseases, Metabolic; Cell Line; Child; Child, Preschool; Collagen; Copper; Ehlers-Danlos Syndrome; Fibroblasts; Histocytochemistry; Humans; Infant; Menkes Kinky Hair Syndrome; Metallothionein; Procollagen-Proline Dioxygenase; Protein-Lysine 6-Oxidase; Skin

The substantial retention of Cu2+ and to a lesser extent Zn2+, in the gut mucosa of neonatal MO mutant mice is largely associated with a low molecular weight protein tentatively identified as metallothionein. [35S]Cysteine incorporation into this protein in mutant mice is elevated, indicating that Cu2+ retention in the gut is associated with an increase in the synthesis of metallothionein. The high Cu2+ levels of mutant gut tissue decline rapidly with age to reach an approximately normal level by 24 days of age; this decline cannot be prevented by dietary supplementation and it is suggested that gut 'closure' and consequent reduced uptake by pinocytosis are important factors in this decline.

Topics: Aging; Animals; Brain Diseases, Metabolic; Carrier Proteins; Copper; Cysteine; Humans; Intestinal Mucosa; Male; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Mice, Mutant Strains; Models, Biological; Zinc

We have assigned the structural gene (Mt-1) coding for the murine metal-binding protein metallothionein I (MT-1) to mouse chromosome 8 by using a cloned DNA probe for mouse Mt-1 in combination with a panel of Chinese hamster-mouse somatic cell hybrid clones segregating mouse chromosomes. Analysis of hybrid cell extracts for the presence of mouse Mt-1 or MT-1 mRNA revealed concordant segregation of Mt-1 with mouse glutathione reductase, an enzyme marker for mouse chromosome 8, but discordant segregation with enzyme markers for 14 other mouse chromosomes. Karyotype analyses of seven informative hybrid clones confirmed the assignment of mouse Mt-1 to chromosome 8. Menkes' disease in man and the mottled mutation (Mo) in the mouse, which provides an animal model of Menkes' disease, are both X-linked degenerative neurologic disorders involving abnormal copper metabolism and increased levels of intracellular metallothionein protein. Fibroblasts from Mo male mice have increased amounts of MT-1 mRNA, suggesting that both Mo and Menkes' disease may be due to a metallothionein gene mutation. However, our assignment of Mt-1 to mouse chromosome 8, rather than the X chromosome, demonstrates that a mutation in mouse Mt-1 or a closely linked regulatory gene is not the primary defect in Mo, and implies that a metallothionein gene mutation is not the genetic defect in human Menkes' disease.

Topics: Animals; Brain Diseases, Metabolic; Chromosome Mapping; Chromosomes; Clone Cells; Cricetinae; Cricetulus; DNA; Female; Genes; Humans; Hybrid Cells; Male; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Mutation; RNA, Messenger; X Chromosome

Copper-binding proteins in the tissues from the patients with Menkes' kinky hair disease were examined by gel filtration on a Sephadex G-75 column. In the kidney, major part of copper was found to bind to low molecular weight protein, which corresponded chromatographically to metallothionein. This copper-binding protein contained a large amount of copper and a small amount of zinc. Cu: Zn ratio of this protein was different from that of metallothionein found in the fetal liver. In the liver of the same patient, however, there was no increase of copper bound to this protein.

Topics: Brain Diseases, Metabolic; Carrier Proteins; Ceruloplasmin; Chromatography, Gel; Copper; Humans; Infant; Kidney; Liver; Male; Menkes Kinky Hair Syndrome; Metallothionein; Zinc

Cultured lymphoblasts derived from infants with Menkes' disease exhibit the same increased avidity for copper as do fibroblasts and most extrahepatic tissues from these patients. The Menkes' cells preferentially take up not only copper but also, on exposure to elevated metal concentrations, the other metallothionein-binding metals, zinc and cadmium. Menkes' lymphoblasts contain larger amounts of metallothionein than normal cells following exposure to each of these metals; the amount bound to this protein quantitatively accounted for the total cellular increment in metal in Menkes' cells. Induction of metallothionein synthesis caused both normal and Menkes' cells to subsequently take up increased amounts of 67Cu. These observations suggest that an enhanced capacity of Menkes' cells to accumulate metallothionein may be responsible for their increased uptake and retention of copper.

Topics: Biological Transport; Brain Diseases, Metabolic; Cadmium; Cell Line; Cell Transformation, Viral; Cells, Cultured; Copper; Herpesvirus 4, Human; Humans; Infant; Kinetics; Lymphocytes; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Reference Values; Zinc

Copper is an essential dietary component, being the coenzyme of many enzymes with oxidase activity, e.g. ceruloplasmin, superoxide dismutase, monoamine oxidase, etc. The metabolism of copper is complex and imperfectly known. Active transport of copper through the intestinal epithelial cells involves metallothionein, a protein rich in sulfhydryl groups which also binds the copper in excess and probably prevents absorption in toxic amounts. In hepatocytes a metallothionein facilitates absorption by a similar mechanism and regulates copper distribution in the liver: incorporation in an apoceruloplasmin, storage and synthesis of copper-dependent enzymes. Metallothioneins and ceruloplasmin are essential to adequate copper homeostasis. Apart from genetic disorders, diseases involving copper usually result from hypercupraemia of varied origin. Wilson's disease and Menkes' disease, although clinically and pathogenetically different, are both marked by low ceruloplasmin and copper serum levels. The excessive liver retention of copper in Wilson's disease might be due to increased avidity of hepatic metallothioneins for copper and decreased biliary excretion through lysosomal dysfunction. Menkes' disease might be due to low avidity of intestinal and hepatic metallothioneins for copper. The basic biochemical defect responsible for these two hereditary conditions has not yet been fully elucidated.

Topics: Adolescent; Adult; Ceruloplasmin; Child; Copper; Hepatolenticular Degeneration; Humans; Infections; Inflammation; Intestinal Absorption; Liver; Menkes Kinky Hair Syndrome; Metabolic Diseases; Metallothionein

Topics: Amino Acids; Animals; Brain Diseases, Metabolic; Cysteine; Disease Models, Animal; Half-Life; Humans; Kidney; Liver; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Mice, Inbred Strains

A metallothionein-like protein (MTP) is synthesized in normal diploid human skin fibroblasts cultured in Zn- or Cu-supplemented medium. Synthesis of MTP is not detected in cells cultured without metal supplementation of complete tissue-culture medium. Cultured fibroblasts from patients with Menkes' disease accumulate excess Cu which chromatographs both with high-molecular-weight protein(s) and with a Cu-MTP. Under normal culture conditions, the Menkes' MTP incorporates [35S]-cystine, but not appreciable amounts of 65Zn. However, Menkes fibroblasts retain the ability to incorporate 65Zn into MTP in response to Zn supplementation of the medium. The results do not support the idea that Menkes' disease results from a failure of Cu to bind to MTP, but rather that an elevated intracellular Cu concentration in Menkes' disease fibroblasts leads to association of excess Cu with high-molecular-weight protein, stimulating synthesis of a Cu-binding MTP.

Topics: Brain Diseases, Metabolic; Cells, Cultured; Copper; Cystine; Fibroblasts; Humans; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Skin; Zinc

The copper utilization in mutated Brindled mice is impaired. Copper accumulates in various tissues, e.g., the kidney, of the mutated mice. The renal copper binding protein is characterized as copper-thionein--metallothionein to which copper is bound. The L-[35S]cystine incorporation experiments without prior induction with copper revealed an abnormal synthesis of metallothionein in the mutated mice. Two models are proposed which link the abnormal metallothionein synthesis with an impaired copper utilization. Model 1 is an unrestrained translation of renal mRNA which codes for metallothionein. Model 2 is an impaired renal copper reabsorption resulting in a toxic intracellular copper concentration which induces metallothionein synthesis to sequester copper. The impaired copper utilization results in a fatal copper deficiency in "Menkes" Brindled mice.

Topics: Animals; Brain Diseases, Metabolic; Copper; Disease Models, Animal; Female; Genotype; Heterozygote; Humans; Male; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Molecular Weight; Mutation; Phenotype; Sex Factors

Topics: Brain Diseases, Metabolic; Cadmium; Copper; Humans; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein

Metallothionein biosynthesis is not induced by extracellular copper in Menkes Kinky hair disease (MKHD) or in normal cultured fibroblasts under the conditions of these experiments. In the presence of copper, MKHD fibroblasts also incorporated less cysteine than did normal fibroblasts. Extracellular cadmium greatly enhanced the uptake of cysteine in both normal and MKHD cultures. By the technique of polyacrylamide gel electrophoresis, it was demonstrated that metallothionein is induced by cadmium in normal and MKHD-cultured fibroblasts.

Topics: Brain Diseases, Metabolic; Cadmium; Cells, Cultured; Copper; Fibroblasts; Humans; Infant; Infant, Newborn; Male; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Skin

Topics: Brain Diseases, Metabolic; Child, Preschool; Copper; Fibroblasts; Humans; Menkes Kinky Hair Syndrome; Metallothionein

Two species of metallothioneins were isolated from both normal and Menkes kinky hair disease (MKHD) patient livers. Atomic absorption determination of metals indicated that the patient liver metallothioneins had lower copper and cadmium content than normals. Isotope exchange studies, carried out by incubating native metallothioneins with copper-64 or cadmium-109 demonstrated a decreased affinity for copper and an increased affinity for cadmium in both MKHD metallothioneins. An hypothesis is proposed in which metallothionein functions as an intracellular copper carrier and is responsible for the transport of copper between the cells and the surrounding. Change in the copper affinity of the metallothioneins was suggested to be the major abnormality in MKHD.

Topics: Adult; Brain Diseases, Metabolic; Cadmium; Child; Chromatography, Gel; Copper; Female; Humans; In Vitro Techniques; Liver; Male; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Protein Binding