N-terminal Domains of Human Copper-transporting Adenosine Triphosphatases (the Wilson's and Menkes Disease Proteins) Bind Copper Selectively in Vivo and in Vitro with Stoichiometry of One Copper Per Metal-binding Repeat

Lutsenko, Svetlana; Petrukhin, Konstantin; Cooper, Matthew J.; Gilliam, C.; Kaplan, Jack H.

doi:10.1074/jbc.272.30.18939

Cited by 229 publications

(202 citation statements)

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“…The CuATPase7b transporter is a P-type ATPase associated with the trans-Golgi network. Although the ATPase7b transporter contains a Cuselective domain (52), the tx J mutation in this protein is associated not only with an elevation of CNS Cu (up to 50%) but also with a 7% elevation in Zn. The question therefore arises as to whether elevated Zn levels contribute to lowering CNS A␤.…”

Section: Discussionmentioning

confidence: 99%

In vivo reduction of amyloid-β by a mutant copper transporter

Phinney

Drisaldi

Schmidt

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

203

153

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Cu ions have been suggested to enhance the assembly and pathogenic potential of the Alzheimer's disease amyloid-␤ (A␤) peptide. To explore this relationship in vivo, toxic-milk (tx J ) mice with a mutant ATPase7b transporter favoring elevated Cu levels were analyzed in combination with the transgenic (Tg) CRND8 amyloid precursor protein mice exhibiting robust A␤ deposition. Unexpectedly, TgCRND8 mice homozygous for the recessive tx J mutation examined at 6 months of age exhibited a reduced number of amyloid plaques and diminished plasma A␤ levels. In addition, homozygosity for tx J increased survival of young TgCRND8 mice and lowered endogenous CNS A␤ at times before detectable increases in Cu in the CNS. These data suggest that the beneficial effect of the tx J mutation on CNS A␤ burden may proceed by a previously undescribed mechanism, likely involving increased clearance of peripheral pools of A␤ peptide. A lzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by extracellular deposition of amyloid-␤ (A␤) as senile plaques and intracellular accumulation of hyperphosphorylated tau as neurofibrillary tangles (1). A␤ is generated by secretase-mediated endoproteolysis of the amyloid precursor protein (APP), and familial AD mutations skew APP processing to favor production of pro-amyloidogenic forms of the peptide or net A␤ production and thus drive disease pathogenesis. Although there is growing interest in defining pathogenic subvarieties of A␤ [e.g., secreted oligomeric assemblies such as A␤-derived diffusible ligands (2) and intracellular forms (3)], modulators of APP and A␤ biology in sporadic disease have remained more elusive. One area of particular interest concerns the role of transition metals.Cu and Zn ions are abundant in the normal brain (4-6), and direct measurements of metal levels have indicated altered homeostasis in AD (7-10). Interestingly, APP has a selective, high-affinity Cu-binding site in the extracellular (ecto-) domain that is capable of reducing Cu(II) to Cu(I) (11), and a recent structural analysis of this domain has revealed some similarity to previously identified Cu chaperone proteins (12). In addition to the ectodomain Cu-binding site of APP, A␤ peptide also contains binding sites for . A␤-metal interaction may drive both fibril formation and free radical production (13,(16)(17)(18), findings potentially relevant to AD pathogenesis in vivo, given that metal chelators can resolubilize A␤ aggregates from postmortem AD brain (19). On the other hand, studies of APP processing in cultured cells have revealed stimulation of the ␣-secretase pathway for APP processing by extracellular Cu ions (20). As this pathway cleaves the A␤ domain of APP into two fragments, it has a potential to be anti-amyloidogenic. Prompted by these divergent observations, we devised a genetic experiment to investigate how Cu might modulate A␤-dependent pathologies in vivo by using the transgenic (Tg) CRND8 line of TgAPP mice (21,22) in conjunction with a mutant allele of the CuATPase7b c...

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Section: Discussionmentioning

confidence: 99%

In vivo reduction of amyloid-β by a mutant copper transporter

Phinney

Drisaldi

Schmidt

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

203

153

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“…Domains 1-4 of WND have also been proposed to function in copper-responsive localization (27,28). Although all six metal-binding domains can bind copper (22,34), their copper-binding affinities are not known. Furthermore, the copper-binding affinity of Atox1 has not been reported.…”

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confidence: 99%

“…Although there are no structures of polypeptides comprising all six repeats from WND or MNK, their metal-binding properties have been studied in some detail. Both the WND and MNK N termini bind 5-6 copper ions (22), and x-ray absorption spectroscopic studies indicate that the copper is present as Cu(I), ligated by the sulfurs from two cysteines (23)(24)(25).…”

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confidence: 99%

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone

Wernimont¹,

Yatsunyk

Rosenzweig

2004

Journal of Biological Chemistry

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The Wilson disease protein (WND) is a transport ATPase involved in copper delivery to the secretory pathway. Mutations in WND and its homolog, the Menkes protein, lead to genetic disorders of copper metabolism. The WND and Menkes proteins are distinguished from other P-type ATPases by the presence of six soluble N-terminal metal-binding domains containing a conserved CXXC metal-binding motif. The exact roles of these domains are not well established, but possible functions include exchanging copper with the metallochaperone Atox1 and mediating copper-responsive cellular relocalization. Although all six domains can bind copper, genetic and biochemical studies indicate that the domains are not functionally equivalent. One way the domains could be tuned to perform different functions is by having different affinities for Cu(I). We have used isothermal titration calorimetry to measure the association constant (K a ) and stoichiometry (n) values of Cu(I) binding to the WND metal-binding domains and to their metallochaperone Atox1. The association constants for both the chaperone and target domains are ϳ10 5 to 10 6 M ؊1 , suggesting that the handling of copper by Atox1 and copper transfer between Atox1 and WND are under kinetic rather than thermodynamic control. Although some differences in both n and K a values are observed for variant proteins containing less than the full complement of six metal-binding domains, the data for domains 1-6 were best fitted with a single site model. Thus, the individual functions of the six WND metal-binding domains are not conferred by different Cu(I) affinities but instead by fold and electrostatic surface properties.

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“…They have a ␤␣␤␤␣␤ fold and an invariant CXXC metal-binding sequence similar to the well described Cu ϩ chaperones, Atox1, Atx1, and CopZ (20,22,23). N-MBDs bind Cu ϩ with high affinity (24)(25)(26), and in vivo, they receive Cu ϩ from the corresponding Cu ϩ chaperones (23,27,28). In bacterial Cu ϩ -ATPases, deletion of these domains or mutation of Cu ϩ -binding Cys residues does not prevent metal activation of the ATPase, although they affect enzyme turnover rate (15,16,19).…”

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confidence: 99%

Mechanism of Cu⁺-transporting ATPases: Soluble Cu⁺chaperones directly transfer Cu⁺to transmembrane transport sites

González‐Guerrero

Argüello

2008

Proc. Natl. Acad. Sci. U.S.A.

214

239

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As in other P-type ATPases, metal binding to transmembrane metal-binding sites (TM-MBS) in Cu ؉ -ATPases is required for enzyme phosphorylation and subsequent transport. However, Cu ؉ does not access Cu ؉ -ATPases in a free (hydrated) form but is bound to a chaperone protein. CopA ͉ CopZ ͉ Cu homeostasis ͉ Cu-ATPase ͉ metal binding C opper is an essential cofactor in many biological processes (1). However, it also participates in harmful Fenton reactions. Consequently, Cu is ''buffered'' at a ''no-free Cu'' level by metallothioneins and chaperones with binding constants for Cu ϩ in the picomolar-femtomolar range (2, 3). Within these constraints, Cu ϩ chaperones route Cu ϩ to various intracellular targets, and Cu ϩ transmembrane transport systems maintain the total copper quota within the 10-100 M range (1-4). How the Cu ϩ chaperones transfer the metal to and from transmembrane transport sites is a central feature of transmembrane Cu ϩ transport. To better understand these phenomena, we have studied the delivery of Cu ϩ by the Archaeoglobus fulgidus Cu ϩ chaperone, CopZ, to the corresponding Cu ϩ -ATPase, CopA.CopA is a member of the P 1B subgroup of P-type ATPases (5-7). Cu ϩ -ATPases are essential to maintain Cu ϩ homeostasis. For instance, mutations in the two Cu ϩ -ATPase genes present in humans, ATP7A and ATP7B, lead to Menkes syndrome and Wilson's disease, respectively (8, 9). The Cu ϩ -ATPases transport cycle follows the classical E1/E2 Albers-Post model (10-12). Catalytic phosphorylation of the enzyme in the E1 conformation occurs upon binding of cytoplasmic metal to transmembrane metal-binding sites (TM-MBS) and ATP binding with high affinity (l M) to the ATP-binding domain (ATP-BD) (Fig. 1). It is assumed that upon phosphorylation, Cu ϩ is occluded within the transmembrane region. The subsequent conformational change allows metal deocclusion and release to the extracellular (vesicular/luminal) compartment followed by enzyme dephosphorylation and return to the E1 form (10). Functional studies of various Cu ϩ -ATPases have characterized the Cu ϩ transport, Cu ϩ -dependent ATPase activity, phosphorylation, and dephosphorylation partial reactions (5,(13)(14)(15)(16)(17)(18)(19).Cu ϩ -ATPases consist of eight transmembrane segments, two large cytosolic loops comprising the A-domain and the ATP-BD, and regulatory metal-binding domains (MBDs) in their N terminus (6, 8-10, 20, 21) (Fig. 1). A. fulgidus CopA has an atypical

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N-terminal Domains of Human Copper-transporting Adenosine Triphosphatases (the Wilson's and Menkes Disease Proteins) Bind Copper Selectively in Vivo and in Vitro with Stoichiometry of One Copper Per Metal-binding Repeat

Cited by 229 publications

References 21 publications

In vivo reduction of amyloid-β by a mutant copper transporter

In vivo reduction of amyloid-β by a mutant copper transporter

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone

Mechanism of Cu⁺-transporting ATPases: Soluble Cu⁺chaperones directly transfer Cu⁺to transmembrane transport sites

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N-terminal Domains of Human Copper-transporting Adenosine Triphosphatases (the Wilson's and Menkes Disease Proteins) Bind Copper Selectively in Vivo and in Vitro with Stoichiometry of One Copper Per Metal-binding Repeat

Cited by 229 publications

References 21 publications

In vivo reduction of amyloid-β by a mutant copper transporter

In vivo reduction of amyloid-β by a mutant copper transporter

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone

Mechanism of Cu+-transporting ATPases: Soluble Cu+chaperones directly transfer Cu+to transmembrane transport sites

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Mechanism of Cu⁺-transporting ATPases: Soluble Cu⁺chaperones directly transfer Cu⁺to transmembrane transport sites