Disulfide cross-linked protein represents a significant fraction of ALS-associated Cu, Zn-superoxide dismutase aggregates in spinal cords of model mice

Yoshiaki Furukawa, Ronggen Fu, Han Xiang Deng, Teepu Siddique, Thomas V. O'Halloran

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Point mutations in Cu, Zn-superoxide dismutase (SOD1) cause a familial form of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Aggregates of mutant SOD1 proteins are observed in histopathology and are invoked in several proposed mechanisms for motor neuronal death; however, the significant stability and activity of the mature mutant proteins are not readily explained in such models. Recent biochemical studies suggest that it is the immature disulfide-reduced forms of the familial ALS mutant SOD1 proteins that play a critical role; these forms tend to misfold, oligomerize, and readily undergo incorrect disulfide formation upon mild oxidative stress in vitro. Here we provide physiological support for this mechanism of aggregate formation and show that a significant fraction of the insoluble SOD1 aggregates in spinal cord of the ALS-model transgenic mice contain multimers cross-linked via intermolecular disulfide bonds. These insoluble disulfide-linked SOD1 multimers are found only in the spinal cord of symptomatic transgenic animals, are not observed in unafflicted tissue such as brain cortex and liver, and can incorporate WT SOD1 protein. The findings provide a biochemical basis for a pathological hallmark of this disease; namely, incorrect disulfide cross-linking of the immature, misfolded mutant proteins leads to insoluble aggregates.

Original languageEnglish
Pages (from-to)7148-7153
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number18
Publication statusPublished - 2006 May 2
Externally publishedYes



  • Disulfide bond
  • Neurodegnerative disease
  • Oxidative stress
  • Protein aggregation

ASJC Scopus subject areas

  • Genetics
  • General

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