Misfolded CuZnSOD and amyotrophic lateral sclerosis.
Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of motor neurons. The inherited form of the disease, familial ALS, represents 5-10% of the total cases, and the best documented of these are due to lesions in SOD1, the gene encoding copper-zinc superoxide dismutase (CuZnSOD). The mechanism by which mutations in SOD1 cause familial ALS is currently unknown. Two hypotheses have dominated recent discussion of the toxicity of ALS mutant CuZnSOD proteins: the oligomerization hypothesis and the oxidative damage hypothesis. The oligomerization hypothesis maintains that mutant CuZnSOD proteins are, or become, misfolded and consequently oligomerize into increasingly high-molecular-weight species that ultimately lead to the death of motor neurons. The oxidative damage hypothesis maintains that ALS mutant CuZnSOD proteins catalyze oxidative reactions that damage substrates critical for viability of the affected cells. This perspective reviews some of the properties of both wild-type and mutant CuZnSOD proteins, suggests how these properties may be relevant to these two hypotheses, and proposes that these two hypotheses are not necessarily mutually exclusive.
Valentine
Joan Selverstone
JS
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90025-1569, USA. jsv@chem.ucla.edu
Hart
P John
PJ
D006801:Humans; D008958:Models, Molecular; D016472:Motor Neuron Disease / Q000201:enzymology* / Q000235:genetics*; D009154:Mutation; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism*
D013482:Superoxide Dismutase