The intracellular localization of the proteasome.

In summary, localization of proteasomes does appear to be important in the regulation of proteolysis. In yeast, a discrete localization is observed at the nuclear periphery for cells undergoing mitotic growth. This localization is clearly important as degradation by the ubiquitin/proteasome pathway is impaired in mutants that mislocalize proteasomes. In mammalian cells, proteasomes are present throughout the cell. However, the proteasome does appear to be enriched at the MTOC upon aggresome formation. The inhibition of the ubiquitin/proteasome pathway in aggresome-containing cells could provide an explanation for the pathogenicity of a number of neurodegenerative diseases.