Ubiquitinated alpha B-crystallin in glial cytoplasmic inclusions from the brain of a patient with multiple system atrophy.

Glial cytoplasmic inclusions (GCIs) have been observed in oligodendroglia-like cells, specifically in the brains of patients with multiple system atrophy (striatonigral degeneration, olivopontocerebellar atrophy and Shy-Drager syndrome). We have investigated GCIs from brains of patients with multiple system atrophy biochemically and immunochemically. While most GCIs have been reported positive for both ubiquitin and alpha B-crystallin in immunocytochemical studies, the components of GCIs have not been identified biochemically. GCI-bearing cells were partially purified from the OPCA brain by sieving with nylon meshes and discontinuous sucrose density gradient centrifugation. The fraction containing GCI-bearing cells was also found to contain a 32 kDa and a 40 kDa protein, both of which were specifically recognized by anti-ubiquitin and anti-alpha B-crystallin antibodies, neither of which was found in the same fraction derived from control brain. These immunochemical results suggest that ubiquitinated alpha B-crystallin is present in GCIs from the brains of patients with multiple system atrophy.