Response to high osmotic conditions and elevated temperature in Saccharomyces cerevisiae is controlled by intracellular glycerol and involves coordinate activity of MAP kinase pathways

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1193-1204 ◽  
Author(s):  
Iwona Wojda ◽  
Rebeca Alonso-Monge ◽  
Jan-Paul Bebelman ◽  
Willem H. Mager ◽  
Marco Siderius
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Osmotic Stress ◽  
Map Kinase ◽  
Growth Temperature ◽  
Wild Type ◽  
Hog Pathway ◽  
Map Kinase Pathway ◽  
Kinase Pathway ◽  
Intracellular Glycerol

In the yeast Saccharomyces cerevisiae, response to an increase in external osmolarity is mediated by the HOG (high osmolarity glycerol) MAP kinase pathway. HOG pathway mutant strains display osmosensitive phenotypes. Recently evidence has been obtained that the osmosensitivity of HOG pathway mutants is reduced during growth at elevated temperature (37 °C). A notable exception is the ste11ssk2ssk22 mutant, which displays hypersensitivity to osmotic stress at 37 °C. This paper reports that overexpression of FPS1 or GPD1 (encoding the glycerol transport facilitator and glycerol-3-phosphate dehydrogenase, respectively, and both affecting intracellular glycerol levels) reduces the hypersensitivity to osmotic stress of ste11ssk2ssk22 at 37 °C. Although in this particular HOG pathway mutant a correlation between suppression of the phenotype and glycerol content could be demonstrated, the absolute level of intracellular glycerol per se does not determine whether a strain is osmosensitive or not. Rather, evidence was obtained that the glycerol level may have an indirect effect, viz. by influencing signalling through the PKC (protein kinase C) MAP kinase pathway, which plays an important role in maintenance of cellular integrity. In order to validate the data obtained with a HOG pathway mutant strain for wild-type yeast cells, MAP kinase signalling under different growth conditions was examined in wild-type strains. PKC pathway signalling, which is manifest at elevated growth temperature by phosphorylation of MAP kinase Mpk1p, is rapidly lost when cells are shifted to high external osmolarity conditions. Expression of bck1-20 or overexpression of WSC3 in wild-type cells resulted in restoration of PKC signalling. Both PKC and HOG signalling, cell wall phenotypes and high osmotic stress responses in wild-type cells were found to be influenced by the growth temperature. The data taken together indicate the intricate interdependence of growth temperature, intracellular glycerol, cell wall structure and MAP kinase signalling in the hyperosmotic stress response of yeast.

Response of Saccharomyces cerevisiae to severe osmotic stress: evidence for a novel activation mechanism of the HOG MAP kinase pathway

2000 ◽  
Vol 37 (2) ◽  
pp. 382-397 ◽  
Author(s):  
O. Van Wuytswinkel ◽  
V. Reiser ◽  
M. Siderius ◽  
M. C. Kelders ◽  
G. Ammerer ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Map Kinase ◽  
Activation Mechanism ◽  
Map Kinase Pathway ◽  
Kinase Pathway

scholarly journals A Mep2-dependent Transcriptional Profile Links Permease Function to Gene Expression during Pseudohyphal Growth in Saccharomyces cerevisiae

2008 ◽  
Vol 19 (7) ◽  
pp. 3028-3039 ◽  
Author(s):  
Julian C. Rutherford ◽  
Gordon Chua ◽  
Timothy Hughes ◽  
Maria E. Cardenas ◽  
Joseph Heitman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Map Kinase ◽  
Molecular Mechanisms ◽  
Nutrient Sensing ◽  
Transcriptional Profile ◽  
Regulatory Function ◽  
Pseudohyphal Growth ◽  
Epistasis Analysis ◽  
Map Kinase Pathway ◽  
Kinase Pathway

The ammonium permease Mep2 is required for the induction of pseudohyphal growth, a process in Saccharomyces cerevisiae that occurs in response to nutrient limitation. Mep2 has both a transport and a regulatory function, supporting models in which Mep2 acts as a sensor of ammonium availability. Potentially similar ammonium permease-dependent regulatory cascades operate in other fungi, and they may also function in animals via the homologous Rh proteins; however, little is known about the molecular mechanisms that mediate ammonium sensing. We show that Mep2 is localized to the cell surface during pseudohyphal growth, and it is required for both filamentous and invasive growth. Analysis of site-directed Mep2 mutants in residues lining the ammonia-conducting channel reveal separation of function alleles (transport and signaling defective; transport-proficient/signaling defective), indicating transport is necessary but not sufficient to sense ammonia. Furthermore, Mep2 overexpression enhances differentiation under normally repressive conditions and induces a transcriptional profile that is consistent with activation of the mitogen-activated protein (MAP) kinase pathway. This finding is supported by epistasis analysis establishing that the known role of the MAP kinase pathway in pseudohyphal growth is linked to Mep2 function. Together, these data strengthen the model that Mep2-like proteins are nutrient sensing transceptors that govern cellular differentiation.

Novel Link between PI 3′ Kinase/p38 Map Kinase Pathway in Dasatinib (BMS354825) Mediated Effect in BCR-ABL Expressing Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4538-4538
Author(s):  
Crystal Lumby ◽  
VeerPal Singh ◽  
Shrisha Reddy ◽  
Sue Sivess-Franks ◽  
Jonathan Dowell ◽  
...  
Keyword(s):  
Map Kinase ◽  
Cell Lines ◽  
P38 Map Kinase ◽  
Pi3 Kinase ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Growth Inhibitory ◽  
Map Kinase Pathway ◽  
Pi3 Kinase Pathway ◽  
Kinase Pathway

Abstract Background: Dasatinib (BMS354825), a dual Src/Abl tyrosine kinase inhibitor, exhibits potent antileukemic effects in vitro and in vivo. Despite the well-established role of BMS354825 in the treatment of imatinib-resistant chronic myelogenous leukemia (CML), the molecular mechanisms that result in generation of antileukemic responses remain unknown. Methods: BCR/ABL (wild type and those carrying mutations: E255K, H396P, Y253F, M351T and T315I) expressing murine BAF3 cell lines were exposed to varying concentrations of BMS354825 for variable times to evaluate for effect on phosphorylation/activation of p38 MAP Kinase and PI3′ Kinase pathway in presence or absence of pharmacologic inhibitors of p38 MAP Kinase and mTOR respectively. Results: In the present study we provide evidence that BMS354825 induces phosphorylation of the p38 MAP Kinase, and activation of its kinase domain, in BCR-ABL expressing cell lines except for those carrying T315I mutation. We also identify the kinases MapKapK-2 which is upregulated in response to BMS354825 as shown by increased phosphorylation of hsp27. Importantly, pharmacological inhibition of p38 MAP Kinase by SB203580 reverses the growth inhibitory effects of BMS354825 on primary leukemic CFU-GM progenitors from patients with CML (see figure). Moreover, SB203580 leads to impairment of the BMS354825 mediated antiproliferative effects in both wild type and mutated CML lines except for those carrying T315I. On the other hand, BMS354825 leads to dephosphorylation of p70S6 Kinase and its downstream effector pathway including down regulation of ribosomal S6. We also report that the pharmacological inhibition of mTOR by Rapamycin augments the growth inhibitory effects of BMS354825 on primary leukemic CFU-GM progenitors from CML patients (see figure). Furthermore, pharmacologic inhibition of p38 MAP Kinase by SB203580 led to reversal of the BMS354825 mediated dephosphorylation of p70 S6 Kinase demonstrating that it maybe downstream of p38 MAP Kinase activation. Altogether, our data establish that activation of the p38 MAP Kinase signaling cascade plays an important role in the generation of the effects of BMS354825 on BCR-ABL expressing cells. Conclusion: We have identified a novel crosstalk mechanism between the p38 MAPK and the PI3′ Kinase pathway which is unique to the effect of BMS354825 in CML. p38 MAP Kinase pathway may play an important role in developing of resistance to BMS354825 in CML. mTOR inhibition may augment effect of BMS354825 in CML and its role in combination with BMS354825 should be explored in resistant disease. Figure Figure

Elevated Leukocyte Alkaline Phosphatase Scores Induced by Jak2 V617F Mutation

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5244-5244
Author(s):  
Seido Oku ◽  
Katsuto Takenaka ◽  
Takashi Kumano ◽  
Takuro Kuriyama ◽  
Shingo Urata ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Map Kinase ◽  
Signaling Pathway ◽  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Wild Type ◽  
Leukocyte Alkaline Phosphatase ◽  
Map Kinase Pathway ◽  
V617f Mutation ◽  
Kinase Pathway

Abstract Leukocyte alkaline phosphatase (LAP) enzymatic activity is a marker of the last stages of myeloid differentiation. The level of LAP is quantitated as the LAP score. Estimation of the LAP score has been useful for distinguishing chronic myelogenous leukemia (CML) from BCR-ABL–negative chronic myeloproliferative disorders (MPDs) and neutrophilic reactions in severe infections. CML patients usually have a low LAP score, whereas elevated LAP scores are seen in patients with polycythemia vera (PV), primary myelofibrosis (PMF), and leukocytosis caused by infections. An acquired Jak2 V617F mutation is seen in approximately 95% of patients with PV and in about 50% of patients with essential thrombocythemia or PMF. It has been shown that Jak2 V617F mutation induced constitutive activation of the JAK-STAT signaling pathway. We speculated that an elevated LAP score might be caused due to activation of JAK-STAT signaling through a Jak2 V617F mutation, and conducted this study to address this question. We analyzed the LAP scores in Jak2 V617F-positive and -negative MPD patients. Jak2 V617F-positive MPD patients had higher LAP scores than Jak2 V617F-negative patients. Moreover, patients carrying homozygous mutations had higher LAP scores than patients with heterozygous mutations. AG490, the Jak2 inhibitor, was shown to significantly decrease the LAP expression in neutrophils of Jak2 V617F-positive patients. We lentivirally transfected the acute promyelocytic leukemia cell line NB4 with the Jak2 V617F mutation and wild-type Jak2 V617F. The expression level of Jak2 was not significantly different between the Jak2 V617F mutation and wild-type Jak2 V617F. We then examined the LAP scores of transfected NB4 cells after these cells were differentiated by all-trans retinoic acid and granulocyte colony stimulating factor. It was observed that the Jak2 V617F mutation and not the wild-type Jak2 induced elevated LAP scores. Furthermore, we showed that Jak2 followed the MAP kinase pathway and not the PI3 kinase pathway, as a downstream signaling pathway to elevate the LAP scores using MEK 1/2 (U0126) and PI3 kinase (LY294002) inhibitors. In conclusion, we obtained direct evidence that Jak2 V617F mutation induces elevated LAP scores via the MAP kinase pathway.

scholarly journals WSC-1 and HAM-7 Are MAK-1 MAP Kinase Pathway Sensors Required for Cell Wall Integrity and Hyphal Fusion in Neurospora crassa

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e42374 ◽  
Author(s):  
Abhiram Maddi ◽  
Anne Dettman ◽  
Ci Fu ◽  
Stephan Seiler ◽  
Stephen J. Free
Keyword(s):  
Cell Wall ◽  
Map Kinase ◽  
Neurospora Crassa ◽  
Cell Wall Integrity ◽  
Hyphal Fusion ◽  
Map Kinase Pathway ◽  
Kinase Pathway
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