scholarly journals The Glc7 type 1 protein phosphatase of Saccharomyces cerevisiae is required for cell cycle progression in G2/M.

1994 ◽  
Vol 14 (5) ◽  
pp. 3158-3165 ◽  
Author(s):  
N Hisamoto ◽  
K Sugimoto ◽  
K Matsumoto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Phosphatase ◽  
Cold Sensitivity ◽  
Growth Defect ◽  
Protein Kinase Activity ◽  
Restrictive Temperature ◽  
Single Mutation ◽  
Permissive Temperature

We isolated a mutant carrying a conditional mutation in the GLC7 gene, encoding the catalytic subunit of a type 1 protein phosphatase, by selection of suppressors that restored the growth defect of cdc24 mutants at high temperature and simultaneously conferred cold-sensitive growth. This cold sensitivity for growth is caused by a single mutation (glc7Y-170) at position 170 of the Glc7 protein, resulting in replacement of cysteine with tyrosine. Genetic analysis suggested that the glc7Y-170 allele is associated with a recessive negative phenotype, reducing the activity of Glc7 in the cell. The glc7Y-170 mutant missegregated chromosome III at the permissive temperature, arrested growth as large-budded cells at the restrictive temperature, exhibited a significant increase in the number of nuclei at or in the neck, and had a short spindle. Furthermore, the glc7Y-170 mutant exhibited a high level of CDC28-dependent protein kinase activity when incubated at the restrictive temperature. These findings suggest that the glc7Y-170 mutation is defective in the G2/M phase of the cell cycle. Thus, type 1 protein phosphatase in Saccharomyces cerevisiae is essential for the G2/M transition.

scholarly journals The EGP1 gene may be a positive regulator of protein phosphatase type 1 in the growth control of Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (7) ◽  
pp. 3767-3776 ◽  
Author(s):  
N Hisamoto ◽  
D L Frederick ◽  
K Sugimoto ◽  
K Tatchell ◽  
K Matsumoto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Protein Phosphatase ◽  
Double Mutant ◽  
Growth Control ◽  
Restrictive Temperature ◽  
Extra Copy ◽  
Additional Gene ◽  
Positive Modulator

The Saccharomyces cerevisiae GLC7 gene encodes the catalytic subunit of type 1 protein phosphatase (PP1) and is required for cell growth. A cold-sensitive glc7 mutant (glc7Y170) arrests in G2/M but remains viable at the restrictive temperature. In an effort to identify additional gene products that function in concert with PP1 to regulate growth, we isolated a mutation (gpp1) that exacerbated the growth phenotype of the glc7Y170 mutation, resulting in rapid death of the double mutant at the nonpermissive temperature. We identified an additional gene, EGP1, as an extra-copy suppressor of the glc7Y170 gpp1-1 double mutant. The nucleotide sequence of EGP1 predicts a leucine-rich repeat protein that is similar to Sds22, a protein from the fission yeast Schizosaccharomyces pombe that positively modulates PP1. EGP1 is essential for cell growth but becomes dispensable upon overexpression of the GLC7 gene. Egp1 and PP1 directly interact, as assayed by coimmunoprecipitation. These results suggest that Egp1 functions as a positive modulator of PP1 in the growth control of S. cerevisiae.

scholarly journals The REG2 gene of Saccharomyces cerevisiae encodes a type 1 protein phosphatase-binding protein that functions with Reg1p and the Snf1 protein kinase to regulate growth.

1996 ◽  
Vol 16 (6) ◽  
pp. 2922-2931 ◽  
Author(s):  
D L Frederick ◽  
K Tatchell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Phosphatase ◽  
Slow Growth ◽  
Glucose Repression ◽  
Growth Defect ◽  
Loss Of Function ◽  
Cell Extracts

The GLC7 gene of Saccharomyces cerevisiae encodes the catalytic subunit of type 1 protein phosphatase (PP1) and is essential for cell growth. We have isolated a previously uncharacterized gene, REG2, on the basis of its ability to interact with Glc7p in the two-hybrid system. Reg2p interacts with Glc7p in vivo, and epitope-tagged derivatives of Reg2p and Glc7p coimmunoprecipitate from cell extracts. The predicted protein product of the REG2 gene is similar to Reg1p, a protein believed to direct PP1 activity in the glucose repression pathway. Mutants with a deletion of reg1 display a mild slow-growth defect, while reg2 mutants exhibit a wild-type phenotype. However, mutants with deletions of both reg1 and reg2 exhibit a severe growth defect. Overexpression of REG2 complements the slow-growth defect of a reg1 mutant but does not complement defects in glycogen accumulation or glucose repression, two traits also associated with a reg1 deletion. These results indicate that REG1 has a unique role in the glucose repression pathway but acts together with REG2 to regulate some as yet uncharacterized function important for growth. The growth defect of a reg1 reg2 double mutant is alleviated by a loss-of-function mutation in the SNF1-encoded protein kinase. The snf1 mutation also suppresses the glucose repression defects of reg1. Together, our data are consistent with a model in which Reg1p and Reg2p control the activity of PP1 toward substrates that are phosphorylated by the Snf1p kinase.

scholarly journals Alanine-Scanning Mutagenesis of Protein Phosphatase Type 1 in the Yeast Saccharomyces cerevisiae

Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 615-626 ◽  
Author(s):  
Stefanie H Baker ◽  
Debra L Frederick ◽  
Andrew Bloecher ◽  
Kelly Tatchell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Protein Phosphatase ◽  
Diverse Range ◽  
Cycle Arrest ◽  
Protein Phosphatase Type 1 ◽  
Wide Range ◽  
Protein Phosphatase Type

Protein phosphatase type 1, encoded by GLC7 in Saccharomyces cerevisiae, is an essential serine/threonine phosphatase implicated in the regulation of a diverse array of physiological functions. We constructed and examined 20 mutant alleles of GLC7 in which codons encoding clusters of charged residues were changed to alanine codons. Three of 20 mutant alleles alter residues in the active site of the phosphatase and are unable to rescue the lethality of a glc7::LEU2 disruption. The 17 alleles that support growth confer a range of mutant traits including cell cycle arrest, 2-deoxyglucose resistance, altered levels of glycogen, sensitivity to high salt, and sporulation defects. For some traits, such as 2-deoxyglucose resistance and cell cycle arrest, the mutated residues map to specific regions of the protein whereas the mutated residues in glycogen-deficient mutants and sporulation-defective mutants are more widely distributed over the protein surface. Many mutants have complex phenotypes, each displaying a diverse range of defects. The wide range of phenotypes identified from the collection of mutant alleles is consistent with the hypothesis that Glc7p-binding proteins, which are thought to regulate the specificity of Glc7p, have overlapping binding sites on the surface of Glc7p. This could account for the high level of sequence conservation found among type 1 protein phosphatases from different species.

scholarly journals The EH-domain-containing protein Pan1 is required for normal organization of the actin cytoskeleton in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (9) ◽  
pp. 4897-4914 ◽  
Author(s):  
H Y Tang ◽  
M Cai
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Calcium Binding ◽  
Ectopic Expression ◽  
Binding Domain ◽  
Actin Binding ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Eh Domain

Normal cell growth and division in the yeast Saccharomyces cerevisiae involve dramatic and frequent changes in the organization of the actin cytoskeleton. Previous studies have suggested that the reorganization of the actin cytoskeleton in accordance with cell cycle progression is controlled, directly or indirectly, by the cyclin-dependent kinase Cdc28. Here we report that by isolating rapid-death mutants in the background of the Start-deficient cdc28-4 mutation, the essential yeast gene PAN1, previously thought to encode the yeast poly(A) nuclease, is identified as a new factor required for normal organization of the actin cytoskeleton. We show that at restrictive temperature, the pan1 mutant exhibited abnormal bud growth, failed to maintain a proper distribution of the actin cytoskeleton, was unable to reorganize actin the cytoskeleton during cell cycle, and was defective in cytokinesis. The mutant also displayed a random pattern of budding even at permissive temperature. Ectopic expression of PAN1 by the GAL promoter caused abnormal distribution of the actin cytoskeleton when a single-copy vector was used. Immunofluorescence staining revealed that the Pan1 protein colocalized with the cortical actin patches, suggesting that it may be a filamentous actin-binding protein. The Pan1 protein contains an EF-hand calcium-binding domain, a putative Src homology 3 (SH3)-binding domain, a region similar to the actin cytoskeleton assembly control protein Sla1, and two repeats of a newly identified protein motif known as the EH domain. These findings suggest that Pan1, recently recognized as not responsible for the poly(A) nuclease activity (A. B. Sachs and J. A. Deardorff, erratum, Cell 83:1059, 1995; R. Boeck, S. Tarun, Jr., M. Rieger, J. A. Deardorff, S. Muller-Auer, and A. B. Sachs, J. Biol. Chem. 271:432-438, 1996), plays an important role in the organization of the actin cytoskeleton in S. cerevisiae.

scholarly journals Cloning and sequence analysis of the Saccharomyces cerevisiae RAD9 gene and further evidence that its product is required for cell cycle arrest induced by DNA damage.

1989 ◽  
Vol 9 (5) ◽  
pp. 1882-1896 ◽  
Author(s):  
R H Schiestl ◽  
P Reynolds ◽  
S Prakash ◽  
L Prakash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Chain Elongation ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Dna Breaks ◽  
Cycle Arrest ◽  
Delta Cells

Procaryotic and eucaryotic cells possess mechanisms for arresting cell division in response to DNA damage. Eucaryotic cells arrest division in the G2 stage of the cell cycle, and various observations suggest that this arrest is necessary to ensure the completion of repair of damaged DNA before the entry of cells into mitosis. Here, we provide evidence that the Saccharomyces cerevisiae RAD9 gene, mutations of which confer sensitivity to DNA-damaging agents, is necessary for the cell cycle arrest phenomenon. Our studies with the rad9 delta mutation show that RAD9 plays a role in the cell cycle arrest of methyl methanesulfonate-treated cells and is absolutely required for the cell cycle arrest in the temperature-sensitive cdc9 mutant, which is defective in DNA ligase. At the restrictive temperature, cell cycle progression of cdc9 cells is blocked sometime after the DNA chain elongation step, whereas cdc9 rad9 delta cells do not arrest at this point and undergo one or two additional divisions. Upon transfer from the restrictive to the permissive temperature, a larger proportion of the cdc9 cells than of the cdc9 rad9 delta cells forms viable colonies, indicating that RAD9-mediated cell cycle arrest allows for proper ligation of DNA breaks before the entry of cells into mitosis. The rad9 delta mutation does not affect the frequency of spontaneous or UV-induced mutation and recombination, suggesting that RAD9 is not directly involved in mutagenic or recombinational repair processes. The RAD9 gene encodes a transcript of approximately 4.2 kilobases and a protein of 1,309 amino acids of Mr 148,412. We suggest that RAD9 may be involved in regulating the expression of genes required for the transition from G2 to mitosis.

Cloning and sequence analysis of the Saccharomyces cerevisiae RAD9 gene and further evidence that its product is required for cell cycle arrest induced by DNA damage

1989 ◽  
Vol 9 (5) ◽  
pp. 1882-1896
Author(s):  
R H Schiestl ◽  
P Reynolds ◽  
S Prakash ◽  
L Prakash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Chain Elongation ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Dna Breaks ◽  
Cycle Arrest ◽  
Delta Cells

Procaryotic and eucaryotic cells possess mechanisms for arresting cell division in response to DNA damage. Eucaryotic cells arrest division in the G2 stage of the cell cycle, and various observations suggest that this arrest is necessary to ensure the completion of repair of damaged DNA before the entry of cells into mitosis. Here, we provide evidence that the Saccharomyces cerevisiae RAD9 gene, mutations of which confer sensitivity to DNA-damaging agents, is necessary for the cell cycle arrest phenomenon. Our studies with the rad9 delta mutation show that RAD9 plays a role in the cell cycle arrest of methyl methanesulfonate-treated cells and is absolutely required for the cell cycle arrest in the temperature-sensitive cdc9 mutant, which is defective in DNA ligase. At the restrictive temperature, cell cycle progression of cdc9 cells is blocked sometime after the DNA chain elongation step, whereas cdc9 rad9 delta cells do not arrest at this point and undergo one or two additional divisions. Upon transfer from the restrictive to the permissive temperature, a larger proportion of the cdc9 cells than of the cdc9 rad9 delta cells forms viable colonies, indicating that RAD9-mediated cell cycle arrest allows for proper ligation of DNA breaks before the entry of cells into mitosis. The rad9 delta mutation does not affect the frequency of spontaneous or UV-induced mutation and recombination, suggesting that RAD9 is not directly involved in mutagenic or recombinational repair processes. The RAD9 gene encodes a transcript of approximately 4.2 kilobases and a protein of 1,309 amino acids of Mr 148,412. We suggest that RAD9 may be involved in regulating the expression of genes required for the transition from G2 to mitosis.

scholarly journals Type 1 protein phosphatase is required for maintenance of cell wall integrity, morphogenesis and cell cycle progression in Saccharomyces cerevisiae

2000 ◽  
Vol 113 (3) ◽  
pp. 507-520 ◽  
Author(s):  
P.D. Andrews ◽  
M.J. Stark
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Wall ◽  
Actin Cytoskeleton ◽  
Map Kinase ◽  
Cell Lysis ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Bud Morphology

GLC7 encodes the catalytic subunit of type 1 protein serine/threonine phosphatase (PP1) in the yeast Saccharomyces cerevisiae. Here we have characterized the temperature-sensitive glc7-10 allele, which displays aberrant bud morphology and an abnormal actin cytoskeleton at the restrictive temperature. At 37 degrees C glc7-10 strains accumulated a high proportion of budded cells with an unmigrated nucleus, duplicated spindle pole bodies, a short spindle, delocalized cortical actin and 2C DNA content, indicating a cell cycle block prior to the metaphase to anaphase transition. glc7-10 was suppressed by growth on high osmolarity medium and exhibited temperature-sensitive cell lysis upon hypo-osmotic stress. Pkc1p, the yeast protein kinase C homolog which is thought to regulate the Mpk1p MAP kinase pathway involved in cell wall remodelling and polarized cell growth, was found to act as a dosage suppressor of glc7-10. Although neither activation of BCK1 (MEKK) by the dominant BCK1-20 mutation nor increased dosage of MKK1 (MEK) or MPK1 (MAP kinase) mimicked PKC1 as a glc7-10 dosage suppressor, extra copies of genes encoding upstream components of the Pkc1p pathway such as ROM2, RHO2, HCS77/WSC1/SLG1 and MID2 also suppressed glc7-10 effectively. Conversely, mpk1delta glc7-10 and bck1delta glc7-10 double mutants displayed a synthetic cell lysis defect compared with each single mutant and glc7-10 was hypersensitive to reduced PKC1 function, displaying highly aberrant morphologies and inviability even at the normally permissive temperature of 26 degrees C. Dephosphorylation by PP1 therefore functions positively to promote cell integrity, bud morphology and polarization of the actin cytoskeleton and glc7-10 cells require higher levels of Pkc1p activity to sustain these functions.

Yeast dom34 Mutants Are Defective in Multiple Developmental Pathways and Exhibit Decreased Levels of Polyribosomes

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 45-56
Author(s):  
Luther Davis ◽  
JoAnne Engebrecht
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Heterologous Expression ◽  
Protein Translation ◽  
Developmental Pathways ◽  
G1 Phase ◽  
Growth Defect ◽  
Wild Type ◽  
Drosophila Homolog ◽  
Mutant Cells

Abstract The DOM34 gene of Saccharomyces cerevisiae is similar togenes found in diverse eukaryotes and archaebacteria. Analysis of dom34 strains shows that progression through the G1 phase of the cell cycle is delayed, mutant cells enter meiosis aberrantly, and their ability to form pseudohyphae is significantly diminished. RPS30A, which encodes ribosomal protein S30, was identified in a screen for high-copy suppressors of the dom34Δ growth defect. dom34Δ mutants display an altered polyribosome profile that is rescued by expression of RPS30A. Taken together, these data indicate that Dom34p functions in protein translation to promote G1 progression and differentiation. A Drosophila homolog of Dom34p, pelota, is required for the proper coordination of meiosis and spermatogenesis. Heterologous expression of pelota in dom34Δ mutants restores wild-type growth and differentiation, suggesting conservation of function between the eukaryotic members of the gene family.

Differential expression of protein phosphatase type 1 isotypes and nucleolin during cell cycle arrest

2007 ◽  
Vol 25 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Hiroyuki Morimoto ◽  
Akiko Ozaki ◽  
Hirohiko Okamura ◽  
Kaya Yoshida ◽  
Bruna Rabelo Amorim ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Differential Expression ◽  
Protein Phosphatase ◽  
Cycle Arrest ◽  
Protein Phosphatase Type 1 ◽  
Protein Phosphatase Type
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