Importance of proteasome-mediated proteolysis and alterations of the ubiquitin/proteasome pathway in cancer cells

Regulated proteolysis is involved in a broad range of biological processes such as cell cycle control, antigen presentation and regulation of gene expression. In most cases studied to date, controlled protein degradation is carried out by the 26S proteasome following ubiquitination of the target protein. The ubiquitin/proteasome pathway is the major intracellular non-lysosomal proteolytic mechanism and is involved in a broad range of processes such as cell cycle progression, antigen presentation and control of gene expression. Recent work reviewed here has shown that this pathway is often the target of cancer-related deregulation and can underlie processes such as oncogenic transformation, tumor progression, escape from immune surveillance and drug resistance. © 2001.