Molecular genetics of intracellular copper transport

Horn, Nina; Tümer, Zeynep

doi:10.1002/(sici)1520-670x(1999)12:4<297::aid-jtra3>3.0.co;2-e

Cited by 14 publications

(8 citation statements)

References 77 publications

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“…Two amino acids of great functional interest were chosen for analysis : the cysteine of the conserved CPx domain in the sixth transmembrane helix, and the conserved HP motif 40 residues C-terminal of the phosphorylated aspartic acid residue (Figure 1). The Menkes disease mutation Cys-1000 Arg (C1000R), changing the conserved CPC motif to Arg-Pro-Cys, has been described as causing a severe phenotype, although with a long survival [29]. A corresponding mutation, C396S, was introduced into CopB.…”

Section: Resultsmentioning

confidence: 99%

“…If the structure of a copper ATPase resembles that of the calcium ATPase, then metal binding, ATP binding and phosphorylation would occur on distinct, widely separated domains [5]. A putative Menkes disease-causing mutation in the CPx-motif, C1000R, has been reported to cause a severe phenotype [15,29]. On the grounds discussed above, such a mutation would be expected to lead to a non-functional Menkes ATPase, and thus cause Menkes disease.…”

Section: Discussionmentioning

confidence: 99%

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Structure‒function analysis of purified Enterococcus hirae CopB copper ATPase: effect of Menkes/Wilson disease mutation homologues

et al. 2001

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The Enterococcus hirae CopB ATPase (EC 3.6.1.3) confers copper resistance to the organism by expelling excess copper. Two related human ATPase genes, ATP7A (EC 3.6.1.36) and ATP7B (EC 3.6.1.36), have been cloned as the loci of mutations causing Menkes and Wilson diseases, diseases of copper metabolism. Many mutations in these genes have been identified in patients. Since it has not yet been possible to purify the human copper ATPases, it has proved difficult to test the impact of mutations on ATPase function. Some mutations occur in highly conserved sequence motifs, suggesting that their effect on function can be tested with a homologous enzyme. Here, we used the E. hirae CopB ATPase to investigate the impact of such mutations on enzyme function in vivo and in vitro. The Menkes disease mutation of Cys-1000-->Arg, changing the conserved Cys-Pro-Cys ('CPC') motif, was mimicked in CopB. The corresponding Cys-396-->Ser CopB ATPase was unable to restore copper resistance in a CopB knock-out mutant in vivo. The purified mutant ATPase still formed an acylphosphate intermediate, but possessed no detectable ATP hydrolytic activity. The most frequent Wilson disease mutation, His-1069-->Gln, was introduced into CopB as His-480-->Gln (H480Q). This mutant CopB also failed to confer copper resistance to a CopB knock-out strain. Purified H480Q CopB formed an acylphosphate intermediate and retained a small, but significant, ATPase activity. Our results reveal that Cys-396 and His-480 of CopB are key residues for ATPase function, and similar roles are suggested for Cys-1000 and His-1069 of Menkes and Wilson ATPases respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Structure‒function analysis of purified Enterococcus hirae CopB copper ATPase: effect of Menkes/Wilson disease mutation homologues

et al. 2001

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“…The N domain includes a GDGIND motif and is important for ATP binding. The sixth transmembrane segment includes a conserved CPC motif important for copper transport …”

Section: Discussionmentioning

confidence: 99%

“…Menkes disease is caused by mutations in ATP7A , such as deletions, insertions, missense mutations, nonsense mutations, splice site mutations, and duplications . Other types of mutations, such as gross deletions including one or several exons, and exon duplications, have also been reported .…”

Section: Discussionmentioning

confidence: 99%

ATP7A mutations in 66 Japanese patients with Menkes disease and carrier detection: A gene analysis

Fujisawa

Kodama

Hiroki

et al. 2019

Pediatrics International

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Background: Menkes disease (MNK; MIN 309400) is an X-linked recessive lethal disorder of copper metabolism caused by mutations in ATP7A (MIM 300011), which encodes a transmembrane copper-transporting P-type ATPase. This study assessed mutations in ATP7A in Japanese patients with MNK and their families using gene analysis. Methods: A total of 66 patients with MNK born between 1975 and 2013 in Japan were investigated in this study. Definite diagnosis of MNK was carried out on polymerase chain reaction (PCR) amplification and direct sequencing of each exon. Genetic analysis was also performed on 39 women for carrier diagnosis, and on nine fetuses and 10 neonates for the diagnosis of MNK. Results: We detected 55 different mutations, of which 20 were de novo mutations. The mutations were located around the six copper binding sites, first to third and six transmembrane domains, and the ATP binding site. Of 30 mothers, 23 (76.7%) were carriers. Approximately half of the male siblings of patients with MNK were also diagnosed with MNK. Conclusion: Mutations in ATP7A varied widely across patients, although approximately half of the mutations were located in exons 4, 9, 10, and 15. Approximately 23% of patients did not inherit the mutations from their mothers, but had de novo mutations. An early definite diagnosis is necessary for the early treatment of MNK, and gene analysis serves as an effective method for detecting mutations in ATP7A.

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“…Many proteins involved in copper homeostasis have thus far been identified in prokaryotes and eukaryotes (for review see Refs. [2][3][4][5].…”

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confidence: 99%

Copper-induced Proteolysis of the CopZ Copper Chaperone ofEnterococcus hirae

Solioz

2001

Journal of Biological Chemistry

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The cop operon is a key element of copper homeostasis in Enterococcus hirae. It encodes two copper ATPases, CopA and CopB, the CopY repressor, and the CopZ metallochaperone. It was previously shown that the transcription of the operon is induced by copper. The concomitant increase in the levels of Cop proteins, particularly the CopB copper export ATPase, allows uncompromised growth of E. hirae in up to 5 mM ambient copper. We here show by Western blotting that the steady-state level of CopZ was increased only up to 0.5 mM copper. At higher copper concentrations, the level of CopZ was decreased and became undetectable at 5 mM media copper. When CopZ was overexpressed from a plasmid, the cells exhibited increased sensitivity to copper and oxidative stress, suggesting that high CopZ expression could become toxic to cells. In wild-type cells, the level of mRNA transcripts from the cop operon remained high in up to 5 mM copper, suggesting that CopZ was proteolyzed. Cell extracts were found to contain a copper-activated proteolytic activity that degraded CopZ in vitro. In this assay, Cu-CopZ was more susceptible to degradation than apo-CopZ. The growth of E. hirae in copper increased the copper-inducible proteolytic activity in extracts. Zymographic studies showed the presence of a copper-dependent protease in crude cell lysates. Thus, copper-stimulated proteolysis plays an important role in the regulation of copper homeostasis in E. hirae.

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Molecular genetics of intracellular copper transport

Cited by 14 publications

References 77 publications

Structure‒function analysis of purified Enterococcus hirae CopB copper ATPase: effect of Menkes/Wilson disease mutation homologues

Structure‒function analysis of purified Enterococcus hirae CopB copper ATPase: effect of Menkes/Wilson disease mutation homologues

ATP7A mutations in 66 Japanese patients with Menkes disease and carrier detection: A gene analysis

Copper-induced Proteolysis of the CopZ Copper Chaperone ofEnterococcus hirae

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