Wild-type Cu/Zn superoxide dismutase (SOD1) does not facilitate, but impedes the formation of protein aggregates of amyotrophic lateral sclerosis causing mutant SOD1

Witan, Heidrun; Gorlovoy, Philipp; Kaya, A Murat; Koziollek-Drechsler, Ingrid; Neumann, Harald; Behl, Christian; Clement, Albrecht M.

doi:10.1016/j.nbd.2009.07.024

Cited by 39 publications

(45 citation statements)

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“…Coexpression of hCCS in the absence of copper also prevented, at least in part, the formation of the unstructured species, and promoted the formation of a mixture of E,Zn-SOD1 SH and E,Zn-SOD1 SS . These observations point to a possible molecular chaperone function of hCCS, as already proposed 45,46 , which would transiently interact with apo-SOD1 SH ARTICLE and stabilize it long enough to allow zinc binding to occur. In the case of G85R no mature protein was formed, even in the presence of Cu(I)-hCCS.…”

Section: Discussionsupporting

confidence: 69%

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In-cell NMR reveals potential precursor of toxic species from SOD1 fALS mutants

et al. 2014

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Mutations in the superoxide dismutase 1 (SOD1) gene are related to familial cases of amyotrophic lateral sclerosis (fALS). Here we exploit in-cell NMR to characterize the protein folding and maturation of a series of fALS-linked SOD1 mutants in human cells and to obtain insight into their behaviour in the cellular context, at the molecular level. The effect of various mutations on SOD1 maturation are investigated by changing the availability of metal ions in the cells, and by coexpressing the copper chaperone for SOD1, hCCS. We observe for most of the mutants the occurrence of an unstructured SOD1 species, unable to bind zinc. This species may be a common precursor of potentially toxic oligomeric species, that are associated with fALS. Coexpression of hCCS in the presence of copper restores the correct maturation of the SOD1 mutants and prevents the formation of the unstructured species, confirming that hCCS also acts as a molecular chaperone.

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Section: Discussionsupporting

confidence: 69%

“…with the immature fALS SOD1 mutants, could exert a role of molecular chaperone for SOD1, as already suggested 45,46 , independent of its role as a copper chaperone, thus modulating the formation of toxic species precursor.…”

Section: Discussionmentioning

confidence: 66%

In-cell NMR reveals potential precursor of toxic species from SOD1 fALS mutants

et al. 2014

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“…In addition, Zn-deficient SOD toxicity is prevented by peptides that inhibit nitration (Ye et al 2007;Sahawneh et al 2010), as is the increased toxicity after the addition of Cu,Zn SOD (Sahawneh et al 2010). Biochemical and biophysical studies indicate that the formation of a dimer between Zn-deficient SOD and Cu,Zn SOD increases the stability of the Zn-deficient SOD monomer Roberts et al 2007), in agreement with the in vivo and in vitro studies showing that wild type SOD increases the stability and solubility of the mutant protein (Fukada et al 2001;Witan et al 2008;Witan et al 2009). Moreover, in spite of Cu,Zn SOD being a very stable enzyme, the half-life for exchange between this enzyme and Zn-deficient SOD at 37°C is surprisingly fast at 13-17 min when determined using differential mobility gel electrophoresis and 14 min by FRET (Roberts et al 2007;Sahawneh et al 2010).…”

Section: Sod1 Toxicitysupporting

confidence: 68%

“…There is some controversy over the effects of wild type SOD on the survival of mice carrying the SOD G85R were one group reported acceleration of disease (Wang et al 2009) and other claims no effect in a different SOD G85R line (Bruijn et al 1998). The mechanism through which coexpression of Cu,Zn SOD wild type increases the toxicity of mutant SOD is controversial, with some groups arguing that aggregation plays a role Furukawa et al 2006), while others conclude that increased solubility of the enzyme contributes to the enhanced toxicity (Fig 8) (Fukada et al 2001;Witan et al 2008;Witan et al 2009;Sahawneh et al 2010). The mechanisms of mutant SOD-induced motor neuron death in the presence of nitric oxide and Zn-deficient SOD stimulation of motor neuron apoptosis in culture seem identical Raoul et al 2002;Sahawneh et al 2010).…”

Section: Sod1 Toxicitymentioning

confidence: 99%

Reactive Nitrogen Species in Motor Neuron Apoptosis

Franco¹,

Estévez²

2012

Amyotrophic Lateral Sclerosis

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“…The mechanism for how co-expression of Cu,Zn-SOD WT increases the toxicity of mutant SOD is controversial, with some groups arguing that aggregation plays a role (27,30) and with others concluding that increased solubility of the enzyme contributes to the enhanced toxicity (26,31,32).…”

mentioning

confidence: 99%

Cu,Zn-Superoxide Dismutase Increases Toxicity of Mutant and Zinc-deficient Superoxide Dismutase by Enhancing Protein Stability*

Sahawneh

Ricart

Roberts

et al. 2010

Journal of Biological Chemistry

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When replete with zinc and copper, amyotrophic lateral sclerosis (ALS)-associated mutant SOD proteins can protect motor neurons in culture from trophic factor deprivation as efficiently as wild-type SOD. However, the removal of zinc from either mutant or wild-type SOD results in apoptosis of motor neurons through a copper-and peroxynitrite-dependent mechanism. It has also been shown that motor neurons isolated from transgenic mice expressing mutant SODs survive well in culture but undergo apoptosis when exposed to nitric oxide via a Fas-dependent mechanism. We combined these two parallel approaches for understanding SOD toxicity in ALS and found that zincdeficient SOD-induced motor neuron death required Fas activation, whereas the nitric oxide-dependent death of G93A SODexpressing motor neurons required copper and involved peroxynitrite formation. Surprisingly, motor neuron death doubled when Cu,Zn-SOD protein was either delivered intracellularly to G93A SOD-expressing motor neurons or co-delivered with zinc-deficient SOD to nontransgenic motor neurons. These results could be rationalized by biophysical data showing that heterodimer formation of Cu,Zn-SOD with zinc-deficient SOD prevented the monomerization and subsequent aggregation of zinc-deficient SOD under thiol-reducing conditions. ALS mutant SOD was also stabilized by mutating cysteine 111 to serine, which greatly increased the toxicity of zinc-deficient SOD. Thus, stabilization of ALS mutant SOD by two different approaches augmented its toxicity to motor neurons. Taken together, these results are consistent with copper-containing zinc-deficient SOD being the elusive "partially unfolded intermediate" responsible for the toxic gain of function conferred by ALS mutant SOD.Mutations to copper/zinc superoxide dismutase (SOD) 4 are the most common genetic cause of the familial form of amyotrophic lateral sclerosis (ALS) (1, 2). Although transgenic expression of these mutant SOD genes in mice and rats is sufficient to produce a progressive motor neuron disease that mimics human pathology (3), the toxic mechanisms remain obscure. Primary motor neuron cultures have proven to be a powerful model to elucidate the toxic gain of function conferred by ALS mutations to SOD and to determine the underlying cell death pathways. Motor neurons isolated from transgenic mice carrying ALS mutant SOD are fully viable in culture (4, 5) but undergo apoptosis after incubation with low, physiologically relevant concentrations of exogenous nitric oxide (50 -100 nM). This remains the most direct evidence that mutant SOD can become directly toxic to motor neurons but also demonstrates that expression of mutant SOD alone may not be sufficient to be toxic to motor neurons.The concentrations of nitric oxide used to induce death of ALS-SOD-expressing motor neurons were not injurious to motor neurons isolated from transgenic mice expressing wildtype SOD and are even trophic to nontransgenic motor neurons (6). Over the past decade, we have accumulated considerable evidence that the reacti...

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Wild-type Cu/Zn superoxide dismutase (SOD1) does not facilitate, but impedes the formation of protein aggregates of amyotrophic lateral sclerosis causing mutant SOD1

Cited by 39 publications

References 50 publications

In-cell NMR reveals potential precursor of toxic species from SOD1 fALS mutants

In-cell NMR reveals potential precursor of toxic species from SOD1 fALS mutants

Reactive Nitrogen Species in Motor Neuron Apoptosis

Cu,Zn-Superoxide Dismutase Increases Toxicity of Mutant and Zinc-deficient Superoxide Dismutase by Enhancing Protein Stability*

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