Identification and distribution of Parkin in rat brain.

Mutations within the amino acid sequence of Parkin, the encoded protein of the parkin gene, appear to trigger the degeneration of dopaminergic neurons in the substantia nigra. Here, the presence and anatomical distribution of Parkin within the rat was examined. Immunoblot analysis of tissue homogenates showed two major bands at 50 and 44kDa. Within the brain, Parkin-containing neurons were identified in the basal ganglia, including the substantia nigra and caudate-putamen. Parkin was visualized in the raphe nucleus, which as in the substantia nigra, was closely localized to monoaminergic-encoding neurons. In addition, Parkin was detected in laminar structures such as the cortex and hippocampus; a substantial number of Parkin-immunoreactive neurons was seen in the cerebellum as well. Parkin therefore is widely distributed in brain pathways implicated in the pathology of Parkinson's disease.