LTE1 encodes a homolog of GDP-GTP exchange factors for the Ras superfamily and is required at low temperatures for cell cycle progression at the stage of the termination of M phase in Saccharomyces cerevisiae. We isolated extragenic suppressors which suppress the cold sensitivity of lte1 cells and confer a temperature-sensitive phenotype on cells. Cells mutant for the suppressor alone were arrested at telophase at non-permissive temperatures and the terminal phenotype was almost identical to that of lte1 cells at non-permissive temperatures. Genetic analysis revealed that the suppressor is allelic to CDC15, which encodesa protein kinase. The cdc15 mutations thus isolated were recessive with regard to the temperature-sensitive phenotype and were dominant with respect to suppression of lte1. We isolated CDC14 as a low-copy-number suppressor of cdc15-rlt1. CDC14 encodes a phosphotyrosine phosphatase (PTPase) and is essential for termination of M phase. An extra copy of CDC14 suppressed the temperature sensitivity of cdc15-rlt1 cells, but not that of cdc15-1 cells. In addition, some residues that are essential for the CDC14 PTPase activity were found to be non-essential for the suppression. These results strongly indicate that Cdc14 possesses dual functions; PTPase activity is needed for one function but not for the other. We postulate that the cooperative action of Cdc14 and Cdc15 plays an essential role in the termination of M phase.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|