S-pombe FEAR protein orthologs are not required for release of Clp1/Flp1 phosphatase from the nucleolus during mitosis

Cdc14 family phosphatases are highly conserved regulators of cell-cycle progression. Two of the best studied members of this family are budding yeast Cdc14p and its fission yeast homolog Clp1p/Flp1p. The function of both Saccharomyces cerevisiae Cdc14p and Schizosaccharomyces pombe Clp1p/Flp1p are controlled in part by their regulated sequestration and release from the nucleolus. In the budding yeast S. cerevisiae a set of proteins collectively termed the FEAR network promote nucleolar and telomeric DNA segregation by triggering the release of the conserved Cdc14 phosphatase from the nucleolus. Here we show that FEAR homologs in S. pombe do not promote release of the Cdc14 homolog Clp1p/Flp1p from the nucleolus, and that Clp1p/Flp1p is not required for nucleolar and telomeric DNA segregation suggesting that this aspect of Cdc14 regulation and function may not be universally conserved.