The Proteasome, a Novel Protease Regulated by Multiple Mechanisms

Investigators have long recognized the potential importance of protein degradation as a mechanism for regulating levels of cellular proteins (1-3). Nevertheless, only recent studies of the ubiquitin-proteasome pathway have shown how extensively proteolysis is involved in the regulation of crucial cellular processes such as: progression of the cell cycle, oncogenesis, transcription, development, growth and atrophy of developed tissues, flux of substrates through metabolic pathways, selective elimination of abnormal proteins, and antigen processing.