Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Copper trafficking in mammalian cells is highly regulated. CCS is a copper chaperone that donates copper to the antioxidant enzyme copper/zinc superoxide dismutase 1 (SOD 1). Mutations of SOD1 are responsible for approximately 20% of familial amyotrophic lateral sclerosis (FALS). Monospecific antibodies were generated to evaluate the localization and cellular distribution of this copper chaperone in human and mouse brain as well as other organs. CCS is found to be ubiquitously expressed by multiple tissues and is present in particularly high concentrations in kidney and liver. In brain and spinal cord, CCS was found throughout the neuropil, with expression largely confined to neurons and some astrocytes. Like SOD1, CCS immunoreactivity was intense in Purkinje cells, deep cerebellar neurons, and pyramidal cortical neurons, whereas in spinal cord, CCS was highly expressed in motor neurons. In cortical neurons, CCS was present in the soma and proximal dendrites, as well as some axons. Although the distribution of CCS paralleled that of SOD1, there was a 12-30-fold molar excess of SOD1 over CCS. That both SOD1 and CCS are present, together, in cells that degenerate in ALS also emphasizes the potential role of CCS in mutant SOD1-mediated toxicity.
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PMID:The copper chaperone CCS is abundant in neurons and astrocytes in human and rodent brain. 988 96

The copper chaperone for superoxide dismutase (CCS) activates the antioxidant enzyme Cu,Zn-SOD (SOD1) by directly inserting the copper cofactor into the apo form of SOD1. Neither the mechanism of protein-protein recognition nor of metal transfer is clear. The metal transfer step has been proposed to occur within a transient copper donor/acceptor complex that is either a heterodimer or heterotetramer (i.e. a dimer of dimers). To determine the nature of this intermediate, we generated a mutant form of SOD1 by replacing a copper binding residue His-48 with phenylalanine. This protein cannot accept copper from CCS but does form a stable complex with apo- and Cu-CCS, as observed by immunoprecipitation and native gel electrophoresis. Fluorescence anisotropy measurements corroborate the formation of this species and further indicate that copper enhances the stability of the dimer by an order of magnitude. The copper form of the heterodimer was isolated by gel filtration chromatography and contains one copper and one zinc atom per heterodimer. These results support a mechanism for copper transfer in which CCS and SOD1 dock via their highly conserved dimer interfaces in a manner that precisely orients the Cys-rich copper donor sites of CCS and the His-rich acceptor sites of SOD1 to form a copper-bridged intermediate.
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PMID:Copper stabilizes a heterodimer of the yCCS metallochaperone and its target superoxide dismutase. 1147 16

The copper chaperone for superoxide dismutase (CCS) activates the eukaryotic antioxidant enzyme copper, zinc superoxide dismutase (SOD1). The 2.9 A resolution structure of yeast SOD1 complexed with yeast CCS (yCCS) reveals that SOD1 interacts with its metallochaperone to form a complex comprising one monomer of each protein. The heterodimer interface is remarkably similar to the SOD1 and yCCS homodimer interfaces. Striking conformational rearrangements are observed in both the chaperone and target enzyme upon complex formation, and the functionally essential C-terminal domain of yCCS is well positioned to play a key role in the metal ion transfer mechanism. This domain is linked to SOD1 by an intermolecular disulfide bond that may facilitate or regulate copper delivery.
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PMID:Heterodimeric structure of superoxide dismutase in complex with its metallochaperone. 1152 66

The antioxidant enzyme Cu,Zn-superoxide dismutase (SOD1) has the distinction of being one of the most abundant disulfide-containing protein known in the eukaryotic cytosol; however, neither catalytic nor physiological roles for the conserved disulfide are known. Here we show that the disulfide status of Saccharomyces cerevisiae SOD1 significantly affects the monomer-dimer equilibrium, the interaction with the copper chaperone CCS, and the activity of the enzyme itself. Disulfide formation in SOD1 by O2 is slow but is greatly accelerated by the Cu-bound form of CCS (Cu-CCS) in vivo and in vitro even in the presence of excess reductants; once formed, this disulfide is kinetically stable. Biochemical assays reveal that Cu-CCS facilitates Cys oxidation and disulfide isomerization in the stepwise conversion of the immature form of the enzyme to the active state. The immature form of SOD1 is most susceptible to oxidative insult and to aggregation reminiscent of that observed in amyotrophic lateral sclerosis. Thus Cu-CCS mediation of correct disulfide formation in SOD1 is important for regulation of enzyme activity and for prevention of misfolding or aggregation.
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PMID:Oxygen-induced maturation of SOD1: a key role for disulfide formation by the copper chaperone CCS. 1521 95

The copper chaperone for superoxide dismutase (CCS) is an intracellular metallochaperone required for incorporation of copper into the essential antioxidant enzyme copper/zinc superoxide dismutase (SOD1). Nutritional studies have revealed that the abundance of CCS is inversely proportional to the dietary and tissue copper content. To determine the mechanisms of copper-dependent regulation of CCS, copper incorporation into SOD1 and SOD1 enzymatic activity as well as CCS abundance and half-life were determined after metabolic labeling of CCS-/- fibroblasts transfected with wild-type or mutant CCS. Wild-type CCS restored SOD1 activity in CCS-/- fibroblasts, and the abundance of this chaperone in these cells was inversely proportional to the copper content of the media, indicating that copper-dependent regulation of CCS is entirely post-translational. Although mutational studies demonstrated no role for CCS Domain I in this copper-dependent regulation, similar analysis of the CXC motif in Domain III revealed a critical role for these cysteine residues in mediating copper-dependent turnover of CCS. Further mutational studies revealed that this CXC-dependent copper-mediated turnover of CCS is independent of the mechanisms of delivery of copper to SOD1 including CCS-SOD1 interaction. Taken together these data demonstrate a mechanism determining the abundance of CCS that is competitive with the process of copper delivery to SOD1, revealing a unique post-translational component of intracellular copper homeostasis.
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PMID:Mechanisms of the copper-dependent turnover of the copper chaperone for superoxide dismutase. 1653 9

Previous studies have demonstrated that N,N-diethyldithiocarbamate (DEDC) elevates copper and promotes oxidative stress within the nervous system. However, whether these effects resolve following cessation of exposure or have the potential to persist and result in cumulative injury has not been determined. In this study, an established model for DEDC myelin injury in the rat was used to determine whether copper levels, oxidative stress, and neuromuscular deficits resolve following the cessation of DEDC exposure. Rats were exposed to DEDC for 8 weeks and then either euthanized or maintained for 2, 6 or 12 weeks after cessation of exposure. At each time point copper levels were measured by inductively coupled mass spectrometry to assess the ability of sciatic nerve, brain, spinal cord and liver to eliminate excess copper post-exposure. The protein expression levels of glutathione transferase alpha, heme oxygenase 1 and superoxide dismutase 1 in peripheral nerve and brain were also determined by western blot to assess levels of oxidative stress as a function of post-exposure duration. As an initial assessment of the bioavailability of the excess copper in brain the protein expression levels of copper chaperone for superoxide dismutase 1, and prion protein were determined by western blot as a function of exposure and post-exposure duration. Neuromuscular function in peripheral nerve was evaluated using grip strengths, nerve conduction velocities, and morphologic changes at the light microscope level. The data demonstrated that in peripheral nerve, copper levels and oxidative stress return to control levels within several weeks after cessation of exposure. Neuromuscular function also showed a trend towards pre-exposure values, although the resolution of myelin lesions was more delayed. In contrast, total copper and antioxidant enzyme levels remained significantly elevated in brain for longer post-exposure periods. The persistence of effects observed in brain suggests that the central nervous system is more susceptible to long-term cumulative adverse effects from dithiocarbamates. Additionally, significant changes in expression levels of chaperone for superoxide dismutase 1, and prion protein were observed consistent with at least a portion of the excess copper being bioactive.
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PMID:Peripheral nerve and brain differ in their capacity to resolve N,N-diethyldithiocarbamate-mediated elevations in copper and oxidative injury. 2045 88

Copper-zinc superoxide dismutase (CuZnSOD; CSD) is an important antioxidant enzyme for oxidative stress protection. To date, two activation pathways have been identified in many species. One requiring the CCS, Cu chaperone for SOD, to insert Cu and activate CSD (referred to as CCS-dependent pathway), and the other works independently of CCS (referred to as CCS-independent pathway). In our previous study, we suggest an unidentified factor will work with glutathione (GSH) for CSD activation in the absence of the CCS. Here, two models of the CCS-independent mechanism are proposed. The role of the unidentified factor may work as a scaffold protein, which provides a platform for the CSD protein and Cu-GSH to interact, or as a Cu carrier, which itself can bind Cu and interact with CSD proteins. We also suggest that the CSD protein conformation at C-terminal is important in providing a docking site for unidentified factor to access.
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PMID:Models for the mechanism for activating copper-zinc superoxide dismutase in the absence of the CCS Cu chaperone in Arabidopsis. 2247 60

Progressive functional maturation of spermatozoa is completed during the transit of these cells through the epididymis, a tubule structure connecting a testicle to a vas deferens. Epididymal epithelial cells by means of their secretory and absorptive functions determine a highly specialized luminal microenvironment containing multiple organic and inorganic components. The latter include copper ions, which due to their redox properties are indispensable for critical homeostatic processes occurring in spermatozoa floating in different part of epididymis but can be potentially toxic. Main purpose of our study was to determine epididymal region-dependent expression and localization of copper transporters ensuring a tight control of copper concentration in epididymal fluid. We also aimed at identifying proteins responsible for copper uptake by spermatozoa and verifying whether this process is coordinated with copper supply to superoxide dismutase 1 (SOD1), a copper-dependent antioxidant enzyme. Our study identifies two ATPases-ATP7A, ATP7B and Slc31a1, major copper importers/exporters depending on their differential expression on epididymal polarized epithelial cells of the caput, corpus, and cauda. Next, ceruloplasmin seems to be a chief protein transporting copper in the epididymal fluid and providing this biometal to spermatozoa. The entry of copper to germ cells is mediated by Slc31a1 and is correlated with both expressions of copper chaperone for superoxide dismutase (CCS), copper chaperone directly providing copper ions to SOD1 and with the expression and activity of the latter. Our results outline a network of cooperating copper binding proteins expressed in epididymal epithelium and in spermatozoa that orchestrate bioavailability of this microelement for gametes and protect them against copper toxicity.
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PMID:Molecular machinery providing copper bioavailability for spermatozoa along the epididymial tubule in mouse. 3099 85