scholarly journals Relationship of the cAMP-dependent protein kinase pathway to the SNF1 protein kinase and invertase expression in Saccharomyces cerevisiae.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 71-80 ◽  
Author(s):  
E J Hubbard ◽  
X L Yang ◽  
M Carlson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Glucose Repression ◽  
Nutrient Utilization ◽  
Growth Defect ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Related Proteins ◽  
Relationship Of

Abstract The SNF1 protein kinase and the associated SNF4 protein are required for release of glucose repression in Saccharomyces cerevisiae. To identify functionally related proteins, we selected genes that in multicopy suppress the raffinose growth defect of snf4 mutants. Among the nine genes recovered were two genes from the cAMP-dependent protein kinase (cAPK) pathway, MSI1 and PDE2. Increased dosage of these genes partially compensates for defects in nutrient utilization and sporulation in snf1 and snf4 null mutants, but does not restore invertase expression. These results suggest that SNF1 and cAPK affect some of the same cellular responses to nutrients. To examine the role of the cAPK pathway in regulation of invertase, we assayed mutants in which the cAPK is not modulated by cAMP. Expression of invertase was regulated in response to glucose and was dependent on SNF1 function. Thus, a cAMP-responsive cAPK is dispensable for regulation of invertase.

sck1, a high copy number suppressor of defects in the cAMP-dependent protein kinase pathway in fission yeast, encodes a protein homologous to the Saccharomyces cerevisiae SCH9 kinase.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 457-467 ◽  
Author(s):  
M Jin ◽  
M Fujita ◽  
B M Culley ◽  
E Apolinario ◽  
M Yamamoto ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Adenylate Cyclase ◽  
Stationary Phase ◽  
Copy Number ◽  
Catalytic Subunit ◽  
High Copy Number ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Abstract Schizosaccharomyces pombe regulates intracellular cAMP levels, and thus cAMP-dependent protein kinase (PKA) activity, in response to changes in nutrient conditions. Mutations in any of eight git genes inhibit glucose repression of fbp1 transcription, alter the cell morphology, and cause a reduction in the growth rate. The eight git genes encode components of an adenylate cyclase activation pathway, adenylate cyclase itself, and the catalytic subunit of PKA. Three of these genes have been identified in other studies as regulators of meiosis. Here we show that the sck1 gene, cloned as a high copy number suppressor of a mutation in git3, is able to suppress the defects conferred by a mutation in any of these git genes. Sequence analysis suggests that sck1 encodes a protein most closely related to the Saccharomyces cerevisiae SCH9 protein kinase that had previously been identified as a high copy number suppressor of mutations in S. cerevisiae that reduce or eliminate PKA activity. Disruption of the sck1 gene causes a significant delay in exit from stationary phase when combined with a disruption of the pka1 (git6) gene encoding the catalytic subunit of PKA. However, the sck1 disruption by itself has little or no effect upon fbp1 transcription, meiosis, or exit from stationary phase, and does not enhance the constitutive fbp1 transcription observed in a pka1 mutant. Therefore, sck1 appears to function in a redundant fashion to pka1, but to varying degrees, in the pathways regulated by pka1.

An Essential Function of a Phosphoinositide-Specific Phospholipase C Is Relieved by Inhibition of a Cyclin-Dependent Protein Kinase in the Yeast Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Jeffrey S Flick ◽  
Jeremy Thorner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Complete Medium ◽  
Restrictive Temperature ◽  
Dependent Protein Kinase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Dependent Protein

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.

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