RRC ID 34854
Author Urushitani M, Kurisu J, Tsukita K, Takahashi R.
Title Proteasomal inhibition by misfolded mutant superoxide dismutase 1 induces selective motor neuron death in familial amyotrophic lateral sclerosis.
Journal J Neurochem
Abstract Accumulating evidence indicates that abnormal conformation of mutant superoxide dismutase 1 (SOD1) is an essential feature underlying the pathogenesis of mutant SOD1-linked familial amyotrophic lateral sclerosis (ALS). Here we investigated the role of ubiquitin-proteasome pathway in the mutant SOD1-related cell death and the effect of oxidative stress on the misfolding of mutant SOD1. Transient overexpression of ubiquitin with human SOD1 (wild-type, ala4val, gly85arg, gly93ala) in Neuro2A cells decreased the amount of mutant SOD1, but not of wild-type, while only mutants were co-immunoprecipitated with poly-ubiquitin. Proteasome inhibition by lactacystin augmented accumulation of mutant SOD1 in the non-ionic detergent-insoluble fraction. The spinal cord lysates from mutant SOD1 transgenic mice showed multiple carbonylated proteins, including mutant SOD1 with SDS-resistant dimer formation. Furthermore, the treatment of hSOD1-expressing cells with hydrogen peroxide promoted the oligomerization, and detergent-insolubility of mutant SOD1 alone, and the oxidized mutant SOD1 proteins were more heavily poly-ubiquitinated. In Neuro2A cells stably expressing human SOD1 protein, the proteasome function measured by chymotrypsin-like activity, was decreased over time without a quantitative alteration of the 20S proteasomal component. Finally, primary motor neurons from the mouse embryonic spinal cord were more vulnerable to lactacystin than non-motor neurons. These results indicate that the sustained expression of mutant SOD1 leads to proteasomal inhibition and motor neuronal death, which in part explains the pathogenesis of mutant SOD1-linked ALS.
Volume 83(5)
Pages 1030-42
Published 2002-12-1
DOI 10.1046/j.1471-4159.2002.01211.x
PII 1211
PMID 12437574
MeSH Amino Acid Substitution Amyotrophic Lateral Sclerosis / enzymology* Amyotrophic Lateral Sclerosis / etiology Animals Cell Death Cells, Cultured Cysteine Endopeptidases / metabolism Disease Models, Animal Enzyme Activation Gene Expression Humans Kidney / cytology Kidney / metabolism Macromolecular Substances Mice Mice, Inbred C57BL Mice, Transgenic Motor Neurons / cytology Motor Neurons / metabolism* Multienzyme Complexes / antagonists & inhibitors* Multienzyme Complexes / metabolism Neuroblastoma / metabolism Oxidative Stress Proteasome Endopeptidase Complex Protein Denaturation Protein Folding* Solubility Superoxide Dismutase / genetics Superoxide Dismutase / metabolism* Superoxide Dismutase-1 Ubiquitin / metabolism
IF 4.066
Times Cited 195
DNA material pcDNA3-SOD1-FLAG_WT (RDB13386) pGEX6p-1-SOD1_WT (RDB13393) pcDNA3-SOD1-FLAG_G85R (RDB13387) pcDNA3-SOD1-FLAG_G93A (RDB13388) pGEX6p-1-SOD1_G93A (RDB13394).