The cdc25 Phosphatase: Biochemistry and Regulation in the Eukaryotic Cell Cycle

Cdc25, a universally conserved M-phase inducer, is a protein phosphatase that directly dephosphorylates and activates the cdc2/cyclin B protein kinase. Recently it has been found that phosphorylation regulates the activity of cdc25 during the cell cycle. The activation of cdc25 can be mediated by cdc2/cyclin B itself thus creating a positive feedback loop. A type-2A phosphatase can specifically dephosphorylate and activate cdc25. In this article we shall review our current knowledge about the regulation of entry into mitosis by the cdc25 phosphatase and its involvement in the self-amplification of MPF in vivo