Expression of ubiquitin and proteasome in motorneurons and astrocytes of spinal cords from patients with amyotrophic lateral sclerosis.

Proteasome, ubiquitin, GFAP and neurofilament were evaluated in motorneurons and astrocytes of spinal cords of ALS and control cases. ALS neurons exhibited ubiquitin positive inclusions and areas of strong immunoreaction for proteasome. Areas of proteasome stain were observed close to neurofilament positive proximal process enlargement. The percentage of neurons strongly immunoreacted, for proteasome was higher in ALS cases than in controls. Many astrocytes were positive for ubiquitin and proteasome. These results suggest that the ubiquitin-proteasome pathway is involved in the ALS pathogenesis and agree with the view that ALS is a disorder of protein aggregation that affects neurons and nonneuronal cells.