Control of the exit from mitosis by the protein phosphatase Cdc14

Very little has been known on the Cdc14 phosphatase from the identification of the temperature-sensitive cdc14 mutant of the yeast Saccharomyces cerevisiae, in 1981, until the last few months, The sequence bf the CDC14 protein, known since; 1992 indicated a protein phosphatase signature. Analysis of the phenotype of the cdc14 mutant pointed out to an essential function of the phosphatase taking place somewhere during the end of mitosis, after separation of the sister chromatids but before inactivation of the Cdc2-cyclin B complex that controls mitosis in all eukaryotic cells. Recent studies conducted by four different research groups have now precisely documented Cdc14 function. Two targets of the phosphatase Cdc14 have thus been uncovered, namely Sic1 and Hct1/Cdh1, both of which had been previously implicated in inhibiting the Cdc2-cyclin B complex and inactivating mitotic cyclins. Cdc14 function is intimately dependent on its intracellular localisation, since Cdc14 has been found to be sequestered within the nucleolus during most of the cell cycle and released from it precisely at the time needed to attain its targets and Hct1/Cdh1, at the end of mitosis.