Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast Saccharomyces cerevisiae responds to osmotic stress, i.e., an increase in osmolarity of the growth medium, by enhanced production and intracellular accumulation of glycerol as a compatible solute. We have cloned a gene encoding the key enzyme of glycerol synthesis, the NADH-dependent cytosolic glycerol-3-phosphate dehydrogenase, and we named it GPD1. gpd1 delta mutants produced very little glycerol, and they were sensitive to osmotic stress. Thus, glycerol production is indeed essential for the growth of yeast cells during reduced water availability. hog1 delta mutants lacking a protein kinase involved in osmostress-induced signal transduction (the high-osmolarity glycerol response [HOG] pathway) failed to increase glycerol-3-phosphate dehydrogenase activity and mRNA levels when osmotic stress was imposed. Thus, expression of GPD1 is regulated through the HOG pathway. However, there may be Hog1-independent mechanisms mediating osmostress-induced glycerol accumulation, since a hog1 delta strain could still enhance its glycerol content, although less than the wild type. hog1 delta mutants are more sensitive to osmotic stress than isogenic gpd1 delta strains, and gpd1 delta hog1 delta double mutants are even more sensitive than either single mutant. Thus, the HOG pathway most probably has additional targets in the mechanism of adaptation to hypertonic medium.
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PMID:GPD1, which encodes glycerol-3-phosphate dehydrogenase, is essential for growth under osmotic stress in Saccharomyces cerevisiae, and its expression is regulated by the high-osmolarity glycerol response pathway. 819 51

Yeast cells respond to hypertonic shock by activation of a (MAP) mitogen-activated protein kinase cascade called the (HOG) high osmolarity glycerol response pathway. How yeast respond to hypotonic shock is unknown. Results of this investigation show that a second MAP kinase cascade in yeast called the protein kinase C1 (PKC1) pathway is activated by hypotonic shock. Tyrosine phosphorylation of the PKC1 pathway MAP kinase increased rapidly in cells following a shift of the external medium to lower osmolarity. The intensity of the response was proportional to the magnitude of the decrease in extracellular osmolarity. This response to hypotonic shock required upstream protein kinases of the PKC1 pathway. Increasing external osmolarity inhibited tyrosine phosphorylation of the PKC1 pathway MAP kinase, a response that was blocked by BCK1-20, a constitutively active mutant in an upstream protein kinase. These results indicate that yeast contain two osmosensing signal transduction pathways, the HOG pathway and the PKC1 pathway, that respond to hypertonic and hypotonic shock, respectively.
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PMID:A second osmosensing signal transduction pathway in yeast. Hypotonic shock activates the PKC1 protein kinase-regulated cell integrity pathway. 853 Apr 23

The yeast PMR2/ENA1 gene encodes an ATPase involved in sodium extrusion and induced by NaCl. At low salt concentrations (0.3 M) induction is mediated by the HOG-MAP kinase pathway, a system activated by non-specific osmotic stress. At high salt concentrations (0.8 M) induction is mediated by the protein phosphatase calcineurin and is specific for sodium. Protein kinase A and Sis2p/Hal3p modulate PMR2/ENA1 expression as negative and positive factors, respectively but Sis2p/Hal3p does not participate in the transduction of the salt signal. Salt stress decreases the level of cAMP and the resulting decrease in protein kinase A activity may contribute to HOG-mediated induction.
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PMID:Multiple transduction pathways regulate the sodium-extrusion gene PMR2/ENA1 during salt stress in yeast. 861 70

Salt tolerance of crops could be improved by genetic engineering if basic questions on mechanisms of salt toxicity and defense responses could be solved at the molecular level. Mutant plants accumulating proline and transgenic plants engineered to accumulate mannitol or fructans exhibit improved salt tolerance. A target of salt toxicity has been identified in Saccharomyces cerevisiae: it is a sodium-sensitive nucleotidase involved in sulfate activation and encoded by the HAL2 gene. The major sodium-extrusion system of S. cerevisiae is a P-ATPase encoded by the ENA1 gene. The regulatory system of ENA1 expression includes the protein phosphatase calcineurin and the product of the HAL3 gene. In Escherichia coli, the Na(+)-H+ antiporter encoded by the nhaA gene is essential for salt tolerance. No sodium transport system has been identified at the molecular level in plants. Ion transport at the vacuole is of crucial importance for salt accumulation in this compartment, a conspicuous feature of halophytic plants. The primary sensors of osmotic stress have been identified only in E. coli. In S. cerevisiae, a protein kinase cascade (the HOG pathway) mediates the osmotic induction of many, but not all, stress-responsive genes. In plants, the hormone abscisic acid mediates many stress responses and both a protein phosphatase and a transcription factor (encoded by the ABI1 and ABI3 genes, respectively) participate in its action.
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PMID:Salt tolerance in plants and microorganisms: toxicity targets and defense responses. 890 Sep 56

Clk/STY, the murine homologue of the recently described LAMMER family of protein kinases, autophosphorylates on serine/threonine and tyrosine residues in vitro and in vivo. LAMMER kinases are found throughout eukaryotes and possess virtually complete amino acid identity in many domains critical for kinase function, leading to the question of whether other family members also possess dual specificity. We report here that the Drosophila family member DOA, human SK-G1, and the Saccharomyces cerevisiae KNS1, all possess protein kinase activity and autophosphorylate with dual specificity in vitro, suggesting that the entire family possesses this activity. Although the LAMMER kinases are closely related to the mitogen-activated protein kinase family, they possess different substrate specificity in vitro, based on phosphorylation of peptide and protein substrates and sequencing of a phosphorylation site in a common substrate.
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PMID:Activity and autophosphorylation of LAMMER protein kinases. 891 Mar 5

High-osmolarity-induced expression of the small heat-shock gene HSP12 is regulated by the HOG (high-osmolarity glycerol) pathway and PKA (protein kinase A). To analyse the regulatory input of both signal transduction pathways, high-salt-induced HSP12 expression in different genetic backgrounds on glucose-, ethanol- and glycerol-based culture media was examined. Upon exposure to high-osmolarity stress, the kinetics of induction of HSP12 in cells growing on the non-fermentable carbon sources are strikingly different from those on glucose. Derepression of HSP12 gene expression under non-stress conditions was observed in cells growing on non-fermentable carbon sources. High-salt challenge resulted in a lower induction of the HSP12 mRNA levels in ethanol-grown cells as compared to glucose-grown cells, whereas in glycerol-grown cells hardly any high-salt induction of HSP12 mRNA levels could be detected. Analysis of signalling through the HOG pathway suggested that glycerol may influence the activity of this signalling route, possible via negative feedback. Furthermore, the cellular level of PKA activity was found to have a great impact on stress-responsive gene transcription. On the basis of the data obtained it was concluded that modulation of PKA activity plays a major role in the stress response. A glucose-dependent, PKA-regulated cellular component is postulated to affect high-osmolarity-induced HSP12 expression.
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PMID:High-osmolarity signalling in Saccharomyces cerevisiae is modulated in a carbon-source-dependent fashion. 935 25

In this report we show that the ENA1/PMR2A gene is under glucose repression. The SNF1 protein kinase, acting independently from the HOG and calcineurin pathways, is essential to release ENA1 from glucose repression. The transcriptional repressor Ssn6p negatively regulates ENA1 expression and, like other glucose repressible genes, this repression is mediated in part by Mig1p. Deletion of a fragment from the ENA1 promoter that includes two Mig1p consensus binding sites gives a high level of expression in glucose without added salt. We suggest that regulation of ENA1 by the SNF1 pathway could be part of a general mechanism through which yeast cells respond to carbon source starvation by activating protective systems against different types of stress.
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PMID:Glucose repression affects ion homeostasis in yeast through the regulation of the stress-activated ENA1 gene. 938 92

Environmental cues direct osteoblasts to proliferate and differentiate. The mitogen-activated protein (MAP) kinase pathways provide a key link between the membrane bound receptors that receive these cues and changes in the pattern of gene expression. The three MAPK cascades in mammalian cells are: the extracellular signal-regulated kinase (ERK) cascade, the stress activated protein kinase/c-jun N-terminal kinase (SAPK/JNK) cascade and the p38MAPK/RK/HOG cascade. Each has varied roles, depending upon the cell type and context, that include transmitting stress, growth, differentiative and apoptotic signals to the nucleus. These pathways target an overlapping set of transcription factors that lead to the differential activation of rapid response genes, particularly members of the fos and jun family of proto-oncogenes. These proteins are the principal components of the transcription factor AP-1, which plays a central role in regulating genes activated early in osteoblast differentiation. We discuss in detail a) the nature and activation of these pathways b) how they induce c-fos expression and c) how these MAPK cascades can differentially regulate the activity of AP-1 and thereby osteoblast-specific gene expression.
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PMID:MAP kinase signaling cascades and gene expression in osteoblasts. 968 34

Activation and control of the yeast HOG (High Osmolarity Glycerol) MAP kinase cascade is accomplished, in part, by a two-component sensory-response circuit comprised of the osmosensing histidine protein kinase Sln1p, the phospho-relay protein Ypd1p, and the response regulator protein Ssk1p. We found that deletion of SLN1 and/or YPD1 reduces reporter gene transcription driven by a second two-component response regulator -- Skn7p. The effect of sln1delta and ypd1delta mutations upon Skn7p activity is dependent on a functional two-component phosphorylation site (D427) in Skn7p, suggesting that Sln1p and Ypd1p may act as phosphodonors for Skn7p. We also observed that loss of PTC1 (a protein serine/threonine phosphatase implicated in negative control of the HOG pathway) in a skn7delta background results in severely retarded growth and in morphological defects. Deletion of either PBS2 or HOG1 alleviates the slow growth phenotype of ptc1delta skn7delta cells, suggesting that Skn7p may participate, in concert with known regulatory components, in modulating HOG pathway activity. The contribution of Skn7p to HOG pathway regulation appears to be modulated by the receiver domain, since non-phosphorylatable Skn7pD427N is unable to fully restore growth to ptc1/skn7 cells.
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PMID:Yeast Skn7p activity is modulated by the Sln1p-Ypd1p osmosensor and contributes to regulation of the HOG pathway. 979 May 91

In this work we report the isolation and characterization of three genes induced by different stress conditions in the yeast Saccharomyces cerevisiae. These genes, named GRE1, GRE2 and GRE3, were identified by the differential display technique using total RNAs obtained from yeast grown under hyperosmotic conditions. Northern analysis of RNA obtained from different growth conditions shows that their corresponding transcripts accumulate not only in response to osmotic stress but also to ionic, oxidative and heat stress. Analysis of the deduced amino acid sequences indicated that GRE1, GRE2 and GRE3 correspond to ORFs YPL223C, YOL151W and YHR104W, respectively. Additionally, it suggested that GRE1 encodes a hydrophilic polypeptide that it is not homologous to any known protein but has features resembling the late embryogenesis abundant (LEA) proteins characterized in higher plants; GRE2 encodes a putative reductase with similarity to plant dihydroflavonol-4-reductases; and GRE3 codifies for a keto-aldose reductase highly related to fungal xylose-reductases. The three genes are induced in the late growth phases in agreement with the presence of PDS elements in their promoter regions. The three of them are under the control of the HOG pathway, even though GRE1 and GRE2 promoter regions do not present the consensus core STRE sequence. In addition, GRE1 and GRE3 are regulated negatively by the cAMP-PKA transduction pathway and positively by the transcriptional factors Msn2p and Msn4p. Gene disruptions of the GRE genes did not show a phenotype in any of the tested stress conditions.
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PMID:Three genes whose expression is induced by stress in Saccharomyces cerevisiae. 1040 68


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