Abstract
The proteasome is a 20S multi-protease complex and consists of a set of small polypeptides with the same evolutionary origin. The 20S proteasome associates reversibly with multiple protein components to form a 26S dumbbell-shaped complex that catalyzes ATP-dependent, selective breakdown of proteins ligated with ubiquitin, suggesting that the 26S complex is a new type of supramolecular, ATP-requiring protease complex in eukaryotic cells. In this review, we summarize the protein and gene structures of proteasomes and discuss the biological function (s) of proteasomes, such as involvement of the ubiquitin pathway, antigen processing/presentation and indispensable role of cell proliferation.
