scholarly journals The Yak1 protein kinase of Saccharomyces cerevisiae moderates thermotolerance and inhibits growth by an Sch9 protein kinase-independent mechanism.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 465-474 ◽  
Author(s):  
A D Hartley ◽  
M P Ward ◽  
S Garrett
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Cell Growth ◽  
Heat Resistance ◽  
Signaling Pathways ◽  
Kinase Activity ◽  
Growth Defect ◽  
Cellular Processes ◽  
Independent Mechanism ◽  
First Time

Abstract The growth defect associated with the loss of yeast A kinase activity can be alleviated by the overexpression or deletion of two other kinases, Sch9 and Yak1, respectively. Using tests of epistasis, we have shown that Sch9 and Yak1 define separate signaling pathways and must, therefore, suppress the A kinase defect by different mechanisms. Nevertheless, the Yak1 kinase appears to regulate cellular processes that are under A kinase control. For example, acquisition of heat resistance is correlated with Yak1 kinase activity, such that YAK1-overexpressing cells are over 200-fold more resistant than isogenic yak1 strains. These results, for the first time, associate a phenotype, other than suppression of the A kinase growth defect, with the loss of Yak1 activity and argue a broader role for the Yak1 kinase in cell growth.

TOR2 Is Part of Two Related Signaling Pathways Coordinating Cell Growth in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Stephen B Helliwell ◽  
Isabelle Howald ◽  
Nik Barbet ◽  
Michael N Hall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Growth ◽  
Actin Cytoskeleton ◽  
Signaling Pathways ◽  
Growth Defect ◽  
G1 Arrest ◽  
Class A ◽  
Class B

Abstract The Saccharomyces cerevisiae genes TOR1 and TOR2 encode phosphatidylinositol kinase homologs. TOR2 has two essential functions. One function overlaps with TOR1 and mediates protein synthesis and cell cycle progression. The second essential function of TOR2 is unique to TOR2 and mediates the cell-cycle-dependent organization of the actin cytoskeleton. We have isolated temperature-sensitive mutants that are defective for either one or both of the two TOR2 functions. The three classes of mutants were as follows. Class A mutants, lacking only the TOR2-unique function, are defective in actin cytoskeleton organization and arrest within two to three generations as small-budded cells in the G2/M phase of the cell cycle. Class B mutants, lacking only the TOR-shared function, and class C mutants, lacking both functions, exhibit a rapid loss of protein synthesis and a G1 arrest within one generation. To define further the two functions of TOR2, we isolated multicopy suppressors that rescue the class A or B mutants. Overexpression of MSS4, PKC1, PLC1, RHO2, ROM2, or SUR1 suppressed the growth defect of a class A mutant. Surprisingly, overexpression of PLC1 and MSS4 also suppressed the growth defect of a class B mutant. These genes encode proteins that are involved in phosphoinositide metabolism and signaling. Thus, the two functions (readouts) of TOR2 appear to involve two related signaling pathways controlling cell growth.

Saccharomyces cerevisiae SSD1-VConfers Longevity by a Sir2p-Independent Mechanism

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1661-1672 ◽  
Author(s):  
Matt Kaeberlein ◽  
Alex A Andalis ◽  
Gregory B Liszt ◽  
Gerald R Fink ◽  
Leonard Guarente
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Span ◽  
Cell Cycle Progression ◽  
Polymorphic Locus ◽  
Cell Integrity ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Maximal Life Span ◽  
Independent Mechanism ◽  
Yeast Aging

AbstractThe SSD1 gene of Saccharomyces cerevisiae is a polymorphic locus that affects diverse cellular processes including cell integrity, cell cycle progression, and growth at high temperature. We show here that the SSD1-V allele is necessary for cells to achieve extremely long life span. Furthermore, addition of SSD1-V to cells can increase longevity independently of SIR2, although SIR2 is necessary for SSD1-V cells to attain maximal life span. Past studies of yeast aging have been performed in short-lived ssd1-d strain backgrounds. We propose that SSD1-V defines a previously undescribed pathway affecting cellular longevity and suggest that future studies on longevity-promoting genes should be carried out in long-lived SSD1-V strains.

scholarly journals Pho85p, a cyclin-dependent protein kinase, and the Snf1p protein kinase act antagonistically to control glycogen accumulation in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (8) ◽  
pp. 4357-4365 ◽  
Author(s):  
D Huang ◽  
I Farkas ◽  
P J Roach
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Mutant Gene ◽  
Glycogen Synthase Kinase ◽  
Partial Purification ◽  
Glycogen Accumulation ◽  
Dependent Protein

In Saccharomyces cerevisiae, nutrient levels control multiple cellular processes. Cells lacking the SNF1 gene cannot express glucose-repressible genes and do not accumulate the storage polysaccharide glycogen. The impaired glycogen synthesis is due to maintenance of glycogen synthase in a hyperphosphorylated, inactive state. In a screen for second site suppressors of the glycogen storage defect of snf1 cells, we identified a mutant gene that restored glycogen accumulation and which was allelic with PHO85, which encodes a member of the cyclin-dependent kinase family. In cells with disrupted PHO85 genes, we observed hyperaccumulation of glycogen, activation of glycogen synthase, and impaired glycogen synthase kinase activity. In snf1 cells, glycogen synthase kinase activity was elevated. Partial purification of glycogen synthase kinase activity from yeast extracts resulted in the separation of two fractions by phenyl-Sepharose chromatography, both of which phosphorylated and inactivated glycogen synthase. The activity of one of these, GPK2, was inhibited by olomoucine, which potently inhibits cyclin-dependent protein kinases, and contained an approximately 36-kDa species that reacted with antibodies to Pho85p. Analysis of Ser-to-Ala mutations at the three potential Gsy2p phosphorylation sites in pho85 cells implicated Ser-654 and/or Thr-667 in PHO85 control of glycogen synthase. We propose that Pho85p is a physiological glycogen synthase kinase, possibly acting downstream of Snf1p.

Invariant phosphorylation of the Saccharomyces cerevisiae Cdc28 protein kinase

1988 ◽  
Vol 8 (7) ◽  
pp. 2976-2979
Author(s):  
J A Hadwiger ◽  
S I Reed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Protein ◽  
Protein Kinase Activity ◽  
Cycle Arrest ◽  
Phosphorylation Level ◽  
Proposed Regulation ◽  
Specific Protein Kinase

The phosphorylation level of the Saccharomyces cerevisiae Cdc28 protein remained invariant under conditions that resulted in cell cycle arrest in the G1 phase and loss of Cdc28-specific protein kinase activity when the activity was assayed in vitro. These results are in contrast to the proposed regulation of the homologous Cdc2 protein kinase of Schizosaccharomyces pombe.

scholarly journals p21-Activated Kinase 5 (Pak5) Localizes to Mitochondria and Inhibits Apoptosis by Phosphorylating BAD

2003 ◽  
Vol 23 (16) ◽  
pp. 5526-5539 ◽  
Author(s):  
Sophie Cotteret ◽  
Zahara M. Jaffer ◽  
Alexander Beeser ◽  
Jonathan Chernoff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Kinase Activity ◽  
Independent Manner ◽  
Promote Neurite Outgrowth ◽  
P21 Activated Kinase ◽  
Kinase A ◽  
Apoptotic Cascade

ABSTRACT Pak5 is the most recently identified and least understood member of the p21-activated kinase (Pak) family. This kinase is known to promote neurite outgrowth in vitro, but its localization, substrates, and effects on cell survival have not been reported. We show here that Pak5 has unique properties that distinguish it from all other members of the Pak family. First, Pak5, unlike Pak1, cannot complement an STE20 mutation in Saccharomyces cerevisiae. Second, Pak5 binds to the GTPases Cdc42 and Rac, but these GTPases do not regulate Pak5 kinase activity, which is constitutive and stronger than any other Pak. Third, Pak5 prevents apoptosis induced by camptothecin and C2-ceramide by phosphorylating BAD on Ser-112 in a protein kinase A-independent manner and prevents the localization of BAD to mitochondria, thereby inhibiting the apoptotic cascade that leads to apoptosis. Finally, we show that Pak5 itself is constitutively localized to mitochondria, and that this localization is independent of kinase activity or Cdc42 binding. These features make Pak5 unique among the Pak family and suggest that it plays an important role in apoptosis through BAD phosphorylation.

scholarly journals The Rapamycin-sensitive Phosphoproteome Reveals That TOR Controls Protein Kinase A Toward Some But Not All Substrates

2010 ◽  
Vol 21 (19) ◽  
pp. 3475-3486 ◽  
Author(s):  
Alexandre Soulard ◽  
Alessio Cremonesi ◽  
Suzette Moes ◽  
Frédéric Schütz ◽  
Paul Jenö ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Protein Kinase ◽  
Cell Growth ◽  
Protein Kinase A ◽  
Ribosome Biogenesis ◽  
Regulatory Subunit ◽  
Nutrient Metabolism ◽  
Cellular Processes ◽  
Targeted Analysis ◽  
Kinase A

Regulation of cell growth requires extensive coordination of several processes including transcription, ribosome biogenesis, translation, nutrient metabolism, and autophagy. In yeast, the protein kinases Target of Rapamycin (TOR) and protein kinase A (PKA) regulate these processes and are thereby the main activators of cell growth in response to nutrients. How TOR, PKA, and their corresponding signaling pathways are coordinated to control the same cellular processes is not understood. Quantitative analysis of the rapamycin-sensitive phosphoproteome combined with targeted analysis of PKA substrates suggests that TOR complex 1 (TORC1) activates PKA but only toward a subset of substrates. Furthermore, we show that TORC1 signaling impinges on BCY1, the negative regulatory subunit of PKA. Inhibition of TORC1 with rapamycin leads to BCY1 phosphorylation on several sites including T129. Phosphorylation of BCY1 T129 results in BCY1 activation and inhibition of PKA. TORC1 inhibits BCY1 T129 phosphorylation by phosphorylating and activating the S6K homolog SCH9 that in turn inhibits the MAP kinase MPK1. MPK1 phosphorylates BCY1 T129 directly. Thus, TORC1 activates PKA toward some substrates by preventing MPK1-mediated activation of BCY1.

scholarly journals Alteration of the Protein Kinase Binding Domain Enhances Function of the Saccharomyces cerevisiae Molecular Chaperone Cdc37

2007 ◽  
Vol 6 (8) ◽  
pp. 1363-1372 ◽  
Author(s):  
Min Ren ◽  
Arti Santhanam ◽  
Paul Lee ◽  
Avrom Caplan ◽  
Stephen Garrett
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Molecular Chaperone ◽  
Binding Domain ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Physical Interaction ◽  
General Function ◽  
Amino Terminal

ABSTRACT Cdc37 is a molecular chaperone that has a general function in the biogenesis of protein kinases. We identified mutations within the putative “protein kinase binding domain” of Cdc37 that alleviate the conditional growth defect of a strain containing a temperature-sensitive allele, tpk2(Ts), of the cyclic AMP-dependent protein kinase (PKA). These dominant mutations alleviate the temperature-sensitive growth defect by elevating PKA activity, as judged by their effects on PKA-regulated processes, localization and phosphorylation of the PKA effector Msn2, as well as in vitro PKA activity. Although the tpk2(Ts) growth defect is also alleviated by Cdc37 overproduction, the CDC37 dominant mutants contain wild-type Cdc37 protein levels. In addition, Saccharomyces cerevisiae Ste11 protein kinase has an elevated physical interaction with the altered Cdc37 protein. These results implicate specific amino-terminal residues in the interaction between Cdc37 and client protein kinases and provide further genetic and biochemical support for a model in which Cdc37 functions as a molecular chaperone for protein kinases.

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