Characterization of Saccharomyces cerevisiae genes encoding subunits of cyclic AMP-dependent protein kinase

1987 ◽  
Vol 7 (8) ◽  
pp. 2653-2663 ◽  
Author(s):  
J F Cannon ◽  
K Tatchell

Mutations in the SRA1 or SRA3 gene eliminate the requirement for either RAS gene (RAS1 or RAS2) in Saccharomyces cerevisiae. We cloned SRA1 and SRA3 and determined their DNA sequences. SRA1 encodes the regulatory subunit of the cyclic AMP (cAMP)-dependent protein kinase and therefore is identical to REG1 and BCY1. This gene is not essential, but its deletion confers many traits: reduction of glycogen accumulation, temperature sensitivity, reduced growth rate on maltose and sucrose, inability to grow on galactose and nonfermentable carbon sources, and nitrogen starvation intolerance. SRA3 is homologous to protein kinases that phosphorylate serine and threonine and likely encodes the catalytic subunit of the cAMP-dependent protein kinase. The wild-type SRA3 gene either triplicated in the chromosome or on episomal, low-copy plasmids behaves like spontaneous dominant SRA3 mutations by suppressing ras2-530 (RAS2::LEU2 disruption), cdc25, and cdc35 mutations. These findings indicate that the yeast RAS genes are dispensable if there is constitutive cAMP-dependent protein kinase activity.

1987 ◽  
Vol 7 (8) ◽  
pp. 2653-2663 ◽  
Author(s):  
J F Cannon ◽  
K Tatchell

Mutations in the SRA1 or SRA3 gene eliminate the requirement for either RAS gene (RAS1 or RAS2) in Saccharomyces cerevisiae. We cloned SRA1 and SRA3 and determined their DNA sequences. SRA1 encodes the regulatory subunit of the cyclic AMP (cAMP)-dependent protein kinase and therefore is identical to REG1 and BCY1. This gene is not essential, but its deletion confers many traits: reduction of glycogen accumulation, temperature sensitivity, reduced growth rate on maltose and sucrose, inability to grow on galactose and nonfermentable carbon sources, and nitrogen starvation intolerance. SRA3 is homologous to protein kinases that phosphorylate serine and threonine and likely encodes the catalytic subunit of the cAMP-dependent protein kinase. The wild-type SRA3 gene either triplicated in the chromosome or on episomal, low-copy plasmids behaves like spontaneous dominant SRA3 mutations by suppressing ras2-530 (RAS2::LEU2 disruption), cdc25, and cdc35 mutations. These findings indicate that the yeast RAS genes are dispensable if there is constitutive cAMP-dependent protein kinase activity.


1987 ◽  
Vol 7 (4) ◽  
pp. 1371-1377 ◽  
Author(s):  
T Toda ◽  
S Cameron ◽  
P Sass ◽  
M Zoller ◽  
J D Scott ◽  
...  

We have cloned a gene (BCY1) from the yeast Saccharomyces cerevisiae that encodes a regulatory subunit of the cyclic AMP-dependent protein kinase. The encoded protein has a structural organization similar to that of the RI and RII regulatory subunits of the mammalian cyclic AMP-dependent protein kinase. Strains of S. cerevisiae with disrupted BCY1 genes do not display a cyclic AMP-dependent protein kinase in vitro, fail to grow on many carbon sources, and are exquisitely sensitive to heat shock and starvation.


1991 ◽  
Vol 11 (6) ◽  
pp. 3369-3373
Author(s):  
R B Wilson ◽  
A A Brenner ◽  
T B White ◽  
M J Engler ◽  
J P Gaughran ◽  
...  

The Saccharomyces cerevisiae SRK1 gene, when expressed on a low-copy shuttle vector, partially suppresses the phenotype associated with elevated levels of cyclic AMP-dependent protein kinase activity and suppresses the temperature-sensitive cell cycle arrest of the ins1 mutant. SRK1 is located on chromosome IV, 3 centimorgans from gcn2. A mutant carrying a deletion mutation in srk1 is viable. SRK1 encodes a 140-kDa protein with homology to the dis3+ protein from Schizosaccharomyces pombe. The ability of SRK1 to alleviate partially the defects caused by high levels of cyclic AMP-dependent protein kinase and the similarity of its encoded protein to dis3+ suggest that SRK1 may have a role in protein phosphatase function.


1992 ◽  
Vol 3 (11) ◽  
pp. 1215-1228 ◽  
Author(s):  
S B Glantz ◽  
J A Amat ◽  
C S Rubin

In mammalian brain, physiological signals carried by cyclic AMP (cAMP) seem to be targeted to effector sites via the tethering of cAMP-dependent protein kinase II beta (PKAII beta) to intracellular structures. Recently characterized A kinase anchor proteins (AKAPs) are probable mediators of the sequestration of PKAII beta because they contain a high-affinity binding site for the regulatory subunit (RII beta) of the kinase and a distinct intracellular targeting domain. To establish a cellular basis for this targeting mechanism, we have employed immunocytochemistry to 1) identify the types of neurons that are enriched in AKAPs, 2) determine the primary intracellular location of the anchor protein, and 3) demonstrate that an AKAP and RII beta are coenriched and colocalized in neurons that utilize the adenylate cyclase-cyclic AMP-dependent protein kinase (PKA) signaling pathway. Antibodies directed against rat brain AKAP 150 were used to elucidate the regional, cellular and intracellular distribution of a prototypic anchor protein in the CNS. AKAP 150 is abundant in Purkinje cells and in neurons of the olfactory bulb, basal ganglia, cerebral cortex, and other forebrain regions. In contrast, little AKAP 150 is detected in neurons of the thalamus, hypothalamus, midbrain, and hindbrain. A high proportion of total AKAP 150 is concentrated in primary branches of dendrites, where it is associated with microtubules. We also discovered that the patterns of accumulation and localization of RII beta (and PKAII beta) in brain are similar to those of AKAP 150. The results suggest that bifunctional AKAP 150 tethers PKAII beta to the dendritic cytoskeleton, thereby creating a discrete target site for the reception and propagation of signals carried by cAMP.


1982 ◽  
Vol 93 (3) ◽  
pp. 727-734 ◽  
Author(s):  
C V Byus ◽  
W H Fletcher

The activation of cyclic AMP-dependent protein kinase has been found to be the predominant mode by which cyclic AMP (cAMP) leads to alterations of a large variety of cellular functions. The activation of the kinase results in the release of the catalytic subunit which as the free enzyme possesses phosphotransferase activity for a variety of specific protein substrates. Using a sensitive and specific cytofluorometric technique we monitored the appearance of free catalytic subunit in Reuber H35 hepatoma cells in culture after incubation with N6-1'-O-dibutyryl-cyclic AMP (DBcAMP), 8-bromoadenosine-3':5'-cyclic monophosphate (8-BrcAMP), and glucagon. The cytochemical method employs the heat-stable inhibitor of the free catalytic subunit which has been conjugated to fluorescein isothiocyanate (F:PKI) and was validated as described in the companion paper (Fletcher and Byus. 1982. J. Cell Biol. 93:719-726). Here we studied the temporal and spatial kinetics of the free catalytic subunit following activation of cAMP-dependent protein kinase by increasing concentrations of DBcAMP,8-BrcAMP, and glucagon. Under similar conditions protein kinase activation was also assessed biochemically in H35 cell supernatants by assaying the protein kinase activity ratio. Incubation of the hepatoma cells with DBcAMP (0.1 mM) led to an increase in the activity ratio from 0.2 in control cultures to a value of nearly 1.0 within a 1- to 2-h period. During this same period using the F:PKI probe, a significant increase in cytoplasmic and nucleolar fluorescence indicative of the release of the free catalytic subunit was coincidentally observed. In contrast to the rapid appearance of catalytic subunit in the cytoplasm and nucleolus of the cell within 5-15 min of the addition of DBcAMP, discernible nucleoplasmic fluorescence did not occur until after 1 h. H35 cell cultures incubated with 8-BrcAMP (0.01-1.0 mM) exhibited a more rapid activation of the protein kinase measured cytochemically compared to the cells treated with DBcAMP. Cultures incubated with 8-BrcAMP had significantly increased cytoplasmic and nucleolar fluorescence compared to unstimulated cells within 1 min of the addition of the analogue and reached a maximal level within 15 min. By employing a microspectrophotometer a distinct dose-dependent increase in cellular fluorescence (i.e., free catalytic subunit) was observed as the concentration of 8-BrcAMP was increased from 0.01 to 1.0 mM at 1, 5, 15, and 60 min following stimulation. The addition of glucagon (10(-6) M) to the culture also led to the activation of cAMP-dependent protein kinase as determined by an increase in the activity ratio. This increase was paralleled throughout the incubation period by a marked elevation in cytoplasmic and nucleolar fluorescence. The results reported herein suggest that both cyclic nucleotide analogues and a polypeptide hormone lead to the activation of cAMP-dependent protein kinase in similar intracellular compartments in Reuber H35 hepatoma cells...


1991 ◽  
Vol 11 (6) ◽  
pp. 3369-3373 ◽  
Author(s):  
R B Wilson ◽  
A A Brenner ◽  
T B White ◽  
M J Engler ◽  
J P Gaughran ◽  
...  

The Saccharomyces cerevisiae SRK1 gene, when expressed on a low-copy shuttle vector, partially suppresses the phenotype associated with elevated levels of cyclic AMP-dependent protein kinase activity and suppresses the temperature-sensitive cell cycle arrest of the ins1 mutant. SRK1 is located on chromosome IV, 3 centimorgans from gcn2. A mutant carrying a deletion mutation in srk1 is viable. SRK1 encodes a 140-kDa protein with homology to the dis3+ protein from Schizosaccharomyces pombe. The ability of SRK1 to alleviate partially the defects caused by high levels of cyclic AMP-dependent protein kinase and the similarity of its encoded protein to dis3+ suggest that SRK1 may have a role in protein phosphatase function.


1992 ◽  
Vol 70 (10-11) ◽  
pp. 1039-1046 ◽  
Author(s):  
Vera Mihajlovic ◽  
Arkadius J. Krolczyk ◽  
Wojtek Auerbach ◽  
Manuel Buchwald ◽  
Bernard P. Schimmer

Caco-2 human colonic carcinoma cells were transfected with an expression vector encoding a mutant form of RI (regulatory subunit of the type 1 cAMP-dependent protein kinase), driven by the metallothionein 1 promoter. A stable transformant was isolated that expressed the mutant RI gene in a Zn2+-inducible manner. The consequences of the RI mutation on cAMP-dependent protein kinase activity, cell division, and regulation of chloride efflux were examined. When grown in the absence of ZnSO4, protein kinase activity in the transformant was stimulated 2.5-fold by cAMP and approached the levels of cAMP-dependent protein kinase activty seen in parental Caco-2 cells; when treated with ZnSO4, cAMP-dependent protein kinase activity in the transformant was inhibited by 60%. In the absence of ZnSO4 the transformant grew with the same doubling time and to the same saturation density as the untransformed parent. In the presence of ZnSO4 the transformant exhibited a cAMP-reversible inhibition of cell division, indicating that a functional cAMP-dependent protein kinase was required for the growth of these cells in culture. Induction of the mutant RI gene also abolished forskolin-stimulated chloride efflux from these cells, suggesting obligatory roles for cAMP and cAMP-dependent protein kinase in forskolin's actions on chloride channel activity. We anticipate that this transformant will be useful for further studies on the roles of cAMP and cAMP-dependent protein kinase in the regulation of intestinal epithelial cells, including regulation of cell proliferation and differentiation, and regulation of chloride channel activity by neurohormones and neurotransmitters.Key words: chloride efflux, cell growth, gene transfer, forskolin.


Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 697-706 ◽  
Author(s):  
S Thompson-Jaeger ◽  
J François ◽  
J P Gaughran ◽  
K Tatchell

Abstract We have isolated a snf1/ccr1 mutant of Saccharomyces cerevisiae which loses viability upon starvation and fails to accumulate glycogen in response to abrupt depletion of phosphate or glucose. A snf1 null mutant is sensitive to heat stress and starvation and fails to accumulate glycogen during growth in rich medium. The phenotypes of the snf1 mutants are those commonly associated with an overactivation of the adenylate cyclase pathway. Mutations in adenylate cyclase or RAS2 which decrease the level of cAMP in the cell moderate the snf1 phenotype. In contrast, a mutation in RAS2 (RAS2val19) which increases the level of cAMP or a mutation in the regulatory subunit (BCY1) of cAMP-dependent protein kinase which results in unregulated cAMP-dependent protein kinase activity accentuates the snf1 phenotype. However, the action of SNF1 in the stress response appears at least partly independent of cAMP-dependent protein kinase because a snf1 phenotype is observed in a strain that lacks all three of the genes that encode the catalytic subunits of cAMP-dependent protein kinase. SNF1 therefore acts at least in part through a cAMP-independent pathway.


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