ROLES OF UBIQUITIN-MEDIATED PROTEOLYSIS IN CELL-CYCLE CONTROL

Selective degradation of cyclins, inhibitors of cyclin-dependent kinas es and anaphase inhibitors is responsible for several major cell cycle transitions. The degradation of these cell cycle regulators is contro lled by the action of target the regulators for degradation by the 26S proteasome. Recent results indicate that two types of multisubunit ub iquitin ligase complexes, which are connected to the protein kinase re gulatory network of the cell cycle in different ways, are responsible for the specific and programmed degradation of many cell cycle regulat ors.