title: Type 1 protein phosphatase acts in opposition to IpL1 protein kinase in regulating yeast chromosome segregation.
abstract: The IPL1 gene is required for high-fidelity chromosome segregation in the budding yeast Saccharomyces cerevisiae. Conditional ipl1ts mutants missegregate chromosomes severely at 37 degrees C. Here, we report that IPL1 encodes an essential putative protein kinase whose function is required during the later part of each cell cycle. At 26 degrees C, the permissive growth temperature, ipl1 mutant cells are defective in the recovery from a transient G2/M-phase arrest caused by the antimicrotubule drug nocodazole. In an effort to identify additional gene products that participate with the Ipl1 protein kinase in regulating chromosome segregation in yeast, a truncated version of the previously identified DIS2S1/GLC7 gene was isolated as a dosage-dependent suppressor of ipl1ts mutations. DIS2S1/GLC7 is predicted to encode a catalytic subunit (PP1C) of type 1 protein phosphatase. Overexpression of the full-length DIS2S1/GLC7 gene results in chromosome missegregation in wild-type cells and exacerbates the mutant phenotype in ipl1 cells. In addition, the glc7-1 mutation can partially suppress the ipl1-1 mutation. These results suggest that type 1 protein phosphatase acts in opposition to the Ipl1 protein kinase in vivo to ensure the high fidelity of chromosome segregation.
authors.affiliation: Department of Microbiology, University of Texas, Austin 78712.
authors.forename: L
authors.initials: L
authors.lastname: Francisco
authors.forename: W
authors.initials: W
authors.lastname: Wang
authors.forename: C S
authors.initials: CS
authors.lastname: Chan
mesh_terms: D000595:Amino Acid Sequence; D064127:Aurora Kinases; D001483:Base Sequence; D002453:Cell Cycle; D015825:Chromosomes, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D006918:Hydroxyurea / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D000072235:Mating Factor; D008969:Molecular Sequence Data; D016296:Mutagenesis; D015739:Nocodazole / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010641:Phenotype; D010675:Pheromones / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D054645:Protein Phosphatase 1; D017346:Protein Serine-Threonine Kinases; D011995:Recombination, Genetic; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; D011494:Protein Kinases; D064127:Aurora Kinases; C576961:IPL1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D015739:Nocodazole; D006918:Hydroxyurea