Altered states: programmed proteolysis and the budding yeast cell cycle

The recent identification of an essential RING-H2 finger protein in the SCF E3 ubiquitin ligase complex of budding yeast has uncovered a family of rel ated E3 enzymes, including the other main cell cycle E3 complex, the anapha se promoting complex (APC), Recent insights into APC-dependent proteolysis include a novel protease activity that dissolves cohesion between sister ch romatids at anaphase, and a crucial phosphatase, Cdc14, whose release from the nucleolus eliminates cyclin-dependent kinase activity and thereby drive s exit from mitosis.