A Novel Functional Domain of Cdc15 Kinase Is Required for Its Interaction With Tem1 GTPase in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1437-1450 ◽  
Author(s):  
Kazuhide Asakawa ◽  
Satoshi Yoshida ◽  
Fumiaki Otake ◽  
Akio Toh-e

Abstract Exit from mitosis requires the inactivation of cyclin-dependent kinase (CDK) activity. In the budding yeast Saccharomyces cerevisiae, a number of gene products have been identified as components of the signal transduction network regulating inactivation of CDK (called the MEN, for the mitotic exit network). Cdc15, one of such components of the MEN, is an essential protein kinase. By the two-hybrid screening, we identified Cdc15 as a binding protein of Tem1 GTPase, another essential regulator of the MEN. Coprecipitation experiments revealed that Tem1 binds to Cdc15 in vivo. By deletion analysis, we found that the Tem1-binding domain resides near the conserved kinase domain of Cdc15. The cdc15-LF mutation, which was introduced into the Tem1-binding domain, reduced the interaction with Cdc15 and Tem1 and caused temperature-sensitive growth.The kinase activity of Cdc15 was not so much affected by the cdc15-LF mutation. However, Cdc15-LF failed to localize to the SPB at the restrictive temperature. Our data show that the interaction with Tem1 is important for the function of Cdc15 and that Cdc15 and Tem1 function in a complex to direct the exit from mitosis.

2006 ◽  
Vol 17 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Yanchang Wang ◽  
Tuen-Yung Ng

In budding yeast Saccharomyces cerevisiae, Cdc5 kinase is a component of mitotic exit network (MEN), which inactivates cyclin-dependent kinase (CDK) after chromosome segregation. cdc5-1 mutants arrest at telophase at the nonpermissive temperature due to the failure of CDK inactivation. To identify more negative regulators of MEN, we carried out a genetic screen for genes that are toxic to cdc5-1 mutants when overexpressed. Genes that encode the B-regulatory subunit (Cdc55) and the three catalytic subunits (Pph21, Pph22, and Pph3) of phosphatase 2A (PP2A) were isolated. In addition to cdc5-1, overexpression of CDC55, PPH21, or PPH22 is also toxic to other temperature-sensitive mutants that display defects in mitotic exit. Consistently, deletion of CDC55 partially suppresses the temperature sensitivity of these mutants. Moreover, in the presence of spindle damage, PP2A mutants display nuclear localized Cdc14, the key player in MEN pathway, indicative of MEN activation. All the evidence suggests the negative role of PP2A in mitotic exit. Finally, our genetic and biochemical data suggest that PP2A regulates the phosphorylation of Tem1, which acts at the very top of MEN pathway.


Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Jeffrey S Flick ◽  
Jeremy Thorner

Abstract The PLC1 gene product of Saccharomyces cerevisiae is a homolog of the δ isoform of mammalian phosphoinositide-specific phospholipase C (PI-PLC). We found that two genes (SPL1 and SPL2), when overexpressed, can bypass the temperature-sensitive growth defect of a plc1Δ cell. SPL1 is identical to the PHO81 gene, which encodes an inhibitor of a cyclin (Pho80p)-dependent protein kinase (Pho85p) complex (Cdk). In addition to overproduction of Pho81p, two other conditions that inactivate this Cdk, a cyclin (pho80Δ) mutation and growth on low-phosphate medium, also permitted growth of plc1Δ cells at the restrictive temperature. Suppression of the temperature sensitivity of plc1Δ cells by pho80Δ does not depend upon the Pho4p transcriptional regulator, the only known substrate of the Pho80p/Pho85p Cdk. The second suppressor, SPL2, encodes a small (17-kD) protein that bears similarity to the ankyrin repeat regions present in Pho81p and in other known Cdk inhibitors. Both pho81Δ and spl2Δ show a synthetic phenotype in combination with plc1Δ. Unlike single mutants, plc1Δ pho81Δ and plc1Δ spl2Δ double mutants were unable to grow on synthetic complete medium, but were able to grow on rich medium.


2001 ◽  
Vol 12 (9) ◽  
pp. 2601-2613 ◽  
Author(s):  
Maria Enquist-Newman ◽  
Iain M. Cheeseman ◽  
David Van Goor ◽  
David G. Drubin ◽  
Pamela B. Meluh ◽  
...  

We showed recently that a complex between Duo1p and Dam1p is required for both spindle integrity and kinetochore function in the budding yeast Saccharomyces cerevisiae. To extend our understanding of the functions and interactions of the Duo1p/Dam1p complex, we analyzed the novel gene product Dad1p (for Duo1 and Dam1 interacting). Dad1p physically associates with Duo1p by two-hybrid analysis, coimmunoprecipitates with Duo1p and Dam1p out of yeast protein extracts, and shows interdependent localization with Duo1p and Dam1p to the mitotic spindle. These results indicate that Dad1p functions as a component of the Duo1p/Dam1p complex. Like Duo1p and Dam1p, Dad1p also localizes to kinetochore regions in chromosomes spreads. Here, we also demonstrate by chromatin immunoprecipitation that Duo1p, Dam1p, and Dad1p associate specifically with centromeric DNA in a manner that is dependent upon Ndc10 and partially dependent upon the presence of microtubules. To explore the functions of Dad1p in vivo, we generated a temperature-sensitive allele, dad1-1. This allele shows spindle defects and a mitotic arrest phenotype that is dependent upon the spindle assembly checkpoint. In addition, dad1-1 mutants undergo chromosome mis-segregation at the restrictive temperature, resulting in a dramatic decrease in viability.


Genetics ◽  
1995 ◽  
Vol 139 (4) ◽  
pp. 1521-1532 ◽  
Author(s):  
K Johzuka ◽  
H Ogawa

Abstract A temperature-sensitive mre11-1 mutation of Saccharomyces cerevisiae causes defects in meiotic recombination and DNA repair during vegetative growth at a restrictive temperature. We cloned the MRE11 gene and found that it encodes a 643-amino acid protein with a highly acidic region containing a heptad repeat of Asp at its C-terminus and is located downstream of YMR44 near the RNA1 locus on the right arm of chromosome XIII. Transcripts of the MRE11 gene increased transiently and showed the same kinetics as that of the RAD50 gene during meiosis. In a mre11 disruption mutant (mre11::hisG), meiosis-specific double-strand break (DSB) formation is abolished. A comparison of the properties of mre11::hisG and a rad50 deletion mutant (rad50 delta) indicated that both mutants exhibited similar phenotypes in both meiosis and mitosis. Characterization of two double mutants, mre11::hisG rad50 delta and mre11::hisG rad50S, showed that MRE11 and RAD50 belong to the same epistasis group with respect to meiotic DSB formation and mitotic DNA repair. Using a two-hybrid system, we found that Mre11 interacts with Rad50 and itself in vivo. These results suggest that Mre11 and Rad50 proteins work in a complex in DSB formation and DNA repair during vegetative growth.


1982 ◽  
Vol 2 (9) ◽  
pp. 1052-1063
Author(s):  
J R Shuster

Temperature-sensitive mutants which arrest in the G1 phase of the cell cycle have been described for the yeast Saccharomyces cerevisiae. One class of these mutants (carrying cdc28, cdc36, cdc37, or cdc39) forms a shmoo morphology at restrictive temperature, characteristic of mating pheromone-arrested wild-type cells. Therefore, one hypothesis to explain the control of cell division by mating factors states that mating pheromones arrest wild-type cells by inactivating one or more of these CDC gene products. A class of mutants (carrying ste4, ste5, ste7, ste11, or ste12) which is insensitive to mating pheromone and sterile has also been described. One possible function of the STE gene products is the inactivation of the CDC gene products in the presence of a mating pheromone. A model incorporating these two hypotheses predicts that such STE gene products will not be required for mating in strains carrying an appropriate cdc lesion. This prediction was tested by assaying the mating abilities of double mutants for all of the pairwise combinations of cdc and ste mutations. Lesions in either cdc36 or cdc39 suppressed the mating defect due to ste4 and ste5. Allele specificity was observed in the suppression of both ste4 and ste5. The results indicate that the CDC36, CDC39, STE4, and STE5 gene products interact functionally or physically or both in the regulation of cell division mediated by the presence or absence of mating pheromones. The cdc36 and cdc39 mutations did not suppress ste7, ste11, or ste12. Lesions in cdc28 or cdc37 did not suppress any of the ste mutations. Other models of CDC and STE gene action which predicted that some of the cdc and ste mutations would be alleles of the same locus were tested. None of the cdc mutations was allelic to the ste mutations and, therefore, these models were eliminated.


1995 ◽  
Vol 15 (5) ◽  
pp. 2589-2599 ◽  
Author(s):  
J Ayté ◽  
J F Leis ◽  
A Herrera ◽  
E Tang ◽  
H Yang ◽  
...  

In Schizosaccharomyces pombe, MBF is a DNA-binding complex suspected to activate the transcription of genes necessary for entry into S phase. The MBF complex contains both p85cdc10 and p72res1/sct1. To obtain a better understanding of how the MBF complex regulates gene expression at the G1/S transition, we have performed a genetic analysis of p72res1. We determined that p72res1 can bind specifically to the cdc22 promoter, when analyzed by gel mobility shift assay, and that the N-terminal 157 amino acids of p72res1 are sufficient for this specific binding. When overexpressed in vivo, a fragment of p72res1 containing this DNA-binding domain could rescue a strain carrying a temperature-sensitive cdc10 allele at the restrictive temperature as well as a strain with a cdc10 null allele. We also determined that the C-terminal region of p72res1 is necessary and sufficient for binding to p85cdc10. Overexpression of the cdc10-binding domain of p72res1 leads to a G1 arrest with a cdc phenotype and a decrease on MBF activity. Overexpression of full-length p72res1 also leads to a growth arrest that can be rescued by overexpression of p85cdc10. These results imply that the MBF activity in vivo is dependent on the interaction of p85cdc10 with p72res1.


Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 739-748 ◽  
Author(s):  
H Mitsuzawa ◽  
I Uno ◽  
T Oshima ◽  
T Ishikawa

Abstract The yeast Saccharomyces cerevisiae contains two ras homologues, RAS1 and RAS2, whose products have been shown to modulate the activity of adenylate cyclase encoded by the CYR1 gene. To isolate temperature-sensitive mutations in the RAS2 gene, we constructed a plasmid carrying a RAS2 gene whose expression is under the control of the galactose-inducible GAL1 promoter. A ras1 strain transformed with this plasmid was subjected to ethyl methanesulfonate mutagenesis and nystatin enrichment. Screening of approximately 13,000 mutagenized colonies for galactose-dependent growth at a high temperature (37 degrees) yielded six temperature-sensitive ras2 (ras2ts) mutations and one temperature-sensitive cyr1 (cyr1ts) mutation that can be suppressed by overexpression or increased dosage of RAS2. Some ras2ts mutations were shown to be suppressed by an extra copy of CYR1. Therefore increased dosage of either RAS2 or CYR1 can suppress the temperature sensitivity caused by a mutation in the other. ras1 ras2ts and ras1 cyr1ts mutants arrested in the G1 phase of the cell cycle at the restrictive temperature, and showed pleiotropic phenotypes to varying degrees even at a temperature permissive for growth (25 degrees), including slow growth, sporulation on rich media, increased accumulation of glycogen, impaired growth on nonfermentable carbon sources, heat-shock resistance, impaired growth on low concentrations of glucose, and lithium sensitivity. Of these, impaired growth on low concentrations of glucose and sensitivity to lithium are new phenotypes, which have not been reported for mutants defective in the cAMP pathway.


Genetics ◽  
2001 ◽  
Vol 159 (4) ◽  
pp. 1547-1558
Author(s):  
Noga Guttmann-Raviv ◽  
Elisabeth Boger-Nadjar ◽  
Iris Edri ◽  
Yona Kassir

Abstract In the budding yeast Saccharomyces cerevisiae initiation and progression through the mitotic cell cycle are determined by the sequential activity of the cyclin-dependent kinase Cdc28. The role of this kinase in entry and progression through the meiotic cycle is unclear, since all cdc28 temperature-sensitive alleles are leaky for meiosis. We used a “heat-inducible Degron system” to construct a diploid strain homozygous for a temperature-degradable cdc28-deg allele. We show that this allele is nonleaky, giving no asci at the nonpermissive temperature. We also show, using this allele, that Cdc28 is not required for premeiotic DNA replication and commitment to meiotic recombination. IME2 encodes a meiosis-specific hCDK2 homolog that is required for the correct timing of premeiotic DNA replication, nuclear divisions, and asci formation. Moreover, in ime2Δ diploids additional rounds of DNA replication and nuclear divisions are observed. We show that the delayed premeiotic DNA replication observed in ime2Δ diploids depends on a functional Cdc28. Ime2Δ cdc28-4 diploids arrest prior to initiation of premeiotic DNA replication and meiotic recombination. Ectopic overexpression of Clb1 at early meiotic times advances premeiotic DNA replication, meiotic recombination, and nuclear division, but the coupling between these events is lost. The role of Ime2 and Cdc28 in initiating the meiotic pathway is discussed.


1990 ◽  
Vol 111 (1) ◽  
pp. 131-142 ◽  
Author(s):  
A E Adams ◽  
D I Johnson ◽  
R M Longnecker ◽  
B F Sloat ◽  
J R Pringle

Budding in the yeast Saccharomyces cerevisiae involves a polarized deposition of new cell surface material that is associated with a highly asymmetric disposition of the actin cytoskeleton. Mutants defective in gene CDC24, which are unable to bud or establish cell polarity, have been of great interest with regard to both the mechanisms of cellular morphogenesis and the mechanisms that coordinate cell-cycle events. To gain further insights into these problems, we sought additional mutants with defects in budding. We report here that temperature-sensitive mutants defective in genes CDC42 and CDC43, like cdc24 mutants, fail to bud but continue growth at restrictive temperature, and thus arrest as large unbudded cells. Nearly all of the arrested cells appear to begin nuclear cycles (as judged by the occurrence of DNA replication and the formation and elongation of mitotic spindles), and many go on to complete nuclear division, supporting the hypothesis that the events associated with budding and those of the nuclear cycle represent two independent pathways within the cell cycle. The arrested mutant cells display delocalized cell-surface deposition associated with a loss of asymmetry of the actin cytoskeleton. CDC42 maps distal to the rDNA on chromosome XII and CDC43 maps near lys5 on chromosome VII.


1998 ◽  
Vol 9 (9) ◽  
pp. 2393-2405 ◽  
Author(s):  
Masafumi Nishizawa ◽  
Masaoki Kawasumi ◽  
Marie Fujino ◽  
Akio Toh-e

In the yeast Saccharomyces cerevisiae, Sic1, an inhibitor of Clb-Cdc28 kinases, must be phosphorylated and degraded in G1for cells to initiate DNA replication, and Cln-Cdc28 kinase appears to be primarily responsible for phosphorylation of Sic1. The Pho85 kinase is a yeast cyclin-dependent kinase (Cdk), which is not essential for cell growth unless both CLN1 andCLN2 are absent. We demonstrate that Pho85, when complexed with Pcl1, a G1cyclin homologue, can phosphorylate Sic1 in vitro, and that Sic1 appears to be more stable inpho85Δ cells. Three consensus Cdk phosphorylation sites present in Sic1 are phosphorylated in vivo, and two of them are required for prompt degradation of the inhibitor. Pho85 and other G1Cdks appear to phosphorylate Sic1 at different sites in vivo. Thus at least two distinct Cdks can participate in phosphorylation of Sic1 and may therefore regulate progression through G1.


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