A Mitogen-Activated Protein Kinase That Senses Nitrogen Regulates Conidial Germination and Growth in Aspergillus fumigatus

ABSTRACT We show that the mitogen-activated protein (MAP) kinase pathway that responds to osmotic stress in Aspergillus fumigatus is also involved in nutritional sensing. This MAP kinase regulates conidial germination in response to the nitrogen source and is activated upon starvation for either carbon or nitrogen during vegetative growth.

Download Full-text

ras2 Controls Morphogenesis, Pheromone Response, and Pathogenicity in the Fungal Pathogen Ustilago maydis

Eukaryotic Cell ◽

10.1128/ec.1.6.954-966.2002 ◽

2002 ◽

Vol 1 (6) ◽

pp. 954-966 ◽

Cited By ~ 78

Author(s):

Nancy Lee ◽

James W. Kronstad

Keyword(s):

Protein Kinase ◽

Map Kinase ◽

Ustilago Maydis ◽

Mitogen Activated Protein Kinase ◽

Gene Encoding ◽

Mitogen Activated Protein ◽

Kinase Cascade ◽

Map Kinase Pathway ◽

Altered Cell ◽

Kinase Pathway

ABSTRACT Ustilago maydis, a pathogen of maize, is a useful model for the analysis of mating, pathogenicity, and the morphological transition between budding and filamentous growth in fungi. As in other fungi, these processes are regulated by conserved signaling mechanisms, including the cyclic AMP (cAMP)/protein kinase A (PKA) pathway and at least one mitogen-activated protein kinase (MAP kinase) pathway. A current challenge is to identify additional factors that lie downstream of the cAMP pathway and that influence morphogenesis in U. maydis. In this study, we identified suppressor mutations that restored budding growth to a constitutively filamentous mutant with a defect in the gene encoding a catalytic subunit of PKA. Complementation of one suppressor mutation unexpectedly identified the ras2 gene, which is predicted to encode a member of the well-conserved ras family of small GTP-binding proteins. Deletion of the ras2 gene in haploid cells altered cell morphology, eliminated pathogenicity on maize seedlings, and revealed a role in the production of aerial hyphae during mating. We also used an activated ras2 allele to demonstrate that Ras2 promotes pseudohyphal growth via a MAP kinase cascade involving the MAP kinase kinase Fuz7 and the MAP kinase Ubc3. Overall, our results reveal an additional level of crosstalk between the cAMP signaling pathway and a MAP kinase pathway influenced by Ras2.

Download Full-text

α1-Adrenergic activation of myocardial Na-K-2Cl cotransport involving mitogen-activated protein kinase

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.275.2.h641 ◽

1998 ◽

Vol 275 (2) ◽

pp. H641-H652 ◽

Cited By ~ 10

Author(s):

Geir Øystein Andersen ◽

Mette Enger ◽

G. Hege Thoresen ◽

Tor Skomedal ◽

Jan-Bjørn Osnes

Keyword(s):

Protein Kinase ◽

Map Kinase ◽

Mitogen Activated Protein Kinase ◽

Extracellular Signal ◽

Rat Hearts ◽

Protein Map ◽

Mitogen Activated Protein ◽

Β Blocker ◽

Map Kinase Pathway ◽

Erk Activity

The translocation mechanisms involved in the α1-adrenoceptor-stimulated efflux of the potassium analog86Rb+were studied in isolated rat hearts. Phenylephrine (in the presence of a β-blocker) increased the efflux of86Rb+and42K+, and the Na-K-2Cl (or K-Cl) cotransport inhibitor bumetanide reduced the response by 42 ± 11%. Furosemide inhibited the response with a lower potency than that of bumetanide. The bumetanide-insensitive efflux was largely sensitive to the K+ channel inhibitor 4-aminopyridine. Inhibitors of the Na+/H+exchanger or the Na+-K+pump had no effect on the increased86Rb+efflux. The activation of the Na-K-2Cl cotransporter was dependent on the extracellular signal-regulated kinase (ERK) subgroup of the mitogen-activated protein (MAP) kinase family. Phenylephrine stimulation increased ERK activity 3.4-fold. PD-98059, an inhibitor of the ERK cascade, reduced both the increased86Rb+efflux and ERK activity. Specific inhibitors of protein kinase C and Ca2+/calmodulin-dependent kinase II had no effect. In conclusion, α1-adrenoceptor stimulation increases86Rb+efflux from the rat heart via K+channels and a Na-K-2Cl cotransporter. Activation of the Na-K-2Cl cotransporter is apparently dependent on the MAP kinase pathway.

Download Full-text

Tyrosine Kinase and Mitogen Activated Protein (MAP) Kinase Pathway on Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage

Brain Disorders & Therapy ◽

10.4172/2168-975x.1000205 ◽

2016 ◽

Vol 05 (01) ◽

Author(s):

Flavio Ramalho Romero ◽

Marco Antonio Zanini

Keyword(s):

Subarachnoid Hemorrhage ◽

Tyrosine Kinase ◽

Map Kinase ◽

Cerebral Vasospasm ◽

Aneurysmal Subarachnoid Hemorrhage ◽

Protein Map ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway

Download Full-text

The K5 Capsule of Escherichia coli Strain Nissle 1917 Is Important in Stimulating Expression of Toll-Like Receptor 5, CD14, MyD88, and TRIF Together with the Induction of Interleukin-8 Expression via the Mitogen-Activated Protein Kinase Pathway in Epithelial Cells

Infection and Immunity ◽

10.1128/iai.01406-09 ◽

2010 ◽

Vol 78 (5) ◽

pp. 2153-2162 ◽

Cited By ~ 26

Author(s):

Mohamed Hafez ◽

Kelly Hayes ◽

Marie Goldrick ◽

Richard K. Grencis ◽

Ian S. Roberts

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Map Kinase ◽

Interleukin 8 ◽

Mitogen Activated Protein Kinase ◽

Probiotic Properties ◽

Toll Like Receptor ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway

ABSTRACT Escherichia coli strain Nissle 1917, which has been widely used as a probiotic for the treatment of inflammatory bowel disorders, expresses a K5 capsule, the expression of which is often associated with extraintestinal and urinary tract isolates of E. coli. Previously, it had been shown that the expression of a K5 capsule by Nissle 1917 was important in mediating interactions with epithelial cells and the extent of chemokine expression. In this paper, we show that infection with Nissle 1917 induces expression of Toll-like receptor 4 (TLR4) and TLR5 in Caco-2 cells and that maximal induction of TLR5 required the K5 capsule. In addition, purified K5 polysaccharide was capable of inducing expression of TLR5 and mCD14 and potentiated the activity of both TLR4 and TLR5 agonists to increase the proinflammatory response. Infection with Nissle 1917 also increased the expression of the adaptor molecules MyD88 and TRIF, which was K5 capsule dependent. By Western blot analysis, it was possible to show that induction of interleukin-8 by Nissle 1917 was predominantly through the mitogen-activated protein (MAP) kinase pathway and that expression of the K5 capsule was important for activation of the MAP kinase pathway. This paper provides new information on the function of the K5 capsule in mediating interactions between Nissle 1917 and epithelial cells and the mechanisms that underlie the probiotic properties of Nissle 1917.

Download Full-text

Modeling the Mitogen Activated Protein (MAP)-Kinase Pathway Using Ordinary Differential Equations

Computational Biology and Bioinformatics ◽

10.11648/j.cbb.20130102.11 ◽

2013 ◽

Vol 1 (2) ◽

pp. 6 ◽

Cited By ~ 1

Author(s):

Sharadwata Pan

Keyword(s):

Differential Equations ◽

Map Kinase ◽

Ordinary Differential Equations ◽

Protein Map ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway

Download Full-text

Specificity of Phosphorylation Responses to Mitogen Activated Protein (MAP) Kinase Pathway Inhibitors in Melanoma Cells

Molecular & Cellular Proteomics ◽

10.1074/mcp.ra117.000335 ◽

2017 ◽

Vol 17 (4) ◽

pp. 550-564 ◽

Cited By ~ 13

Author(s):

Joel Basken ◽

Scott A. Stuart ◽

Andrew J. Kavran ◽

Thomas Lee ◽

Christopher C. Ebmeier ◽

...

Keyword(s):

Map Kinase ◽

Melanoma Cells ◽

Protein Map ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway

Download Full-text

Differential regulation of Raf-1 and B-Raf and Ras-dependent activation of mitogen-activated protein kinase by cyclic AMP in PC12 cells.

Molecular and Cellular Biology ◽

10.1128/mcb.15.10.5524 ◽

1995 ◽

Vol 15 (10) ◽

pp. 5524-5530 ◽

Cited By ~ 102

Author(s):

P Erhardt ◽

J Troppmair ◽

U R Rapp ◽

G M Cooper

Keyword(s):

Growth Factor ◽

Cyclic Amp ◽

Map Kinase ◽

Pc12 Cells ◽

Dominant Negative ◽

Mitogen Activated Protein Kinase ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway ◽

Stimulation Of

Growth factor stimulation of the mitogen-activated protein (MAP) kinase pathway in fibroblasts is inhibited by cyclic AMP (cAMP) as a result of inhibition of Raf-1. In contrast, cAMP inhibits neither nerve growth factor-induced MAP kinase activation nor differentiation in PC12 pheochromocytoma cells. Instead, in PC12 cells cAMP activates MAP kinase. Since one of the major differences between the Ras/Raf/MAP kinase cascades of these cell types is the expression of B-Raf in PC12 cells, we compared the effects of cAMP on Raf-1 and B-Raf. In PC12 cells maintained in serum-containing medium, B-Raf was refractory to inhibition by cAMP, whereas Raf-1 was effectively inhibited. In contrast, both B-Raf and Raf-1 were inhibited by cAMP in serum-starved PC12 cells. The effect of cAMP is thus dependent upon growth conditions, with B-Raf being resistant to cAMP inhibition in the presence of serum. These results were extended by studies of Rat-1 fibroblasts into which B-Raf had been introduced by transfection. As in PC12 cells, B-Raf was resistant to inhibition by cAMP in the presence of serum, whereas Raf-1 was effectively inhibited. In addition, the expression of B-Raf rendered Rat-1 cells resistant to the inhibitory effects of cAMP on both growth factor-induced activation of MAP kinase and mitogenesis. These results indicate that Raf-1 and B-Raf are differentially sensitive to inhibition by cAMP and that B-Raf expression can contribute to cell type-specific differences in the regulation of the MAP kinase pathway. In contrast to the situation in PC12 cells, cAMP by itself did not stimulate MAP kinase in B-Raf-expressing Rat-1 cells. The activation of MAP kinase by cAMP in PC12 cells was inhibited by the expression of a dominant negative Ras mutant, indicating that cAMP acts on a target upstream of Ras. Thus, it appears that a signaling component upstream of Ras is also require for cAMP stimulation of MAP kinase in PC12 cells.

Download Full-text

The Colletotrichum lagenarium Ste12-Like Gene CST1 Is Essential for Appressorium Penetration

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.4.315 ◽

2003 ◽

Vol 16 (4) ◽

pp. 315-325 ◽

Cited By ~ 75

Author(s):

Gento Tsuji ◽

Satoshi Fujii ◽

Seiji Tsuge ◽

Tomonori Shiraishi ◽

Yasuyuki Kubo

Keyword(s):

Map Kinase ◽

Lipid Droplets ◽

Map Kinases ◽

Cellulose Membrane ◽

Appressorium Formation ◽

Colletotrichum Lagenarium ◽

Protein Map ◽

Mitogen Activated Protein ◽

Map Kinase Pathway ◽

Kinase Pathway

Colletotrichum lagenarium is the causal agent of anthracnose of cucumber. This fungus produces a darkly melanized infection structure, appressoria, to penetrate the host leaves. The C. lagenarium CMK1 gene, a homologue of the Saccharomyces cerevisiae FUS3/KSS1 mitogen-activated protein (MAP) kinase genes, was shown to regulate conidial germination, appressorium formation, and invasive growth. In S. cerevisiae, Ste12p is known to be a transcriptional factor downstream of Fus3p/Kss1p MAP kinases. To evaluate the CMK1 MAP kinase pathway, we isolated the Ste12 homologue CST1 gene from C. lagenarium and characterized. The cst1Δ strains were nonpathogenic on intact host leaves, but could form lesions when inoculated on wounded leaves. Conidia of the cst1Δ strains could germinate and form melanized appressoria on both host leaf surface and artificial cellulose membrane, but could not produce infectious hyphae from appressoria, suggesting that CST1 is essential for appressorium penetration in C. lagenarium. In addition, matured appressoria of the cst1Δ strains contained an extremely low level of lipid droplets compared with that of the wild-type strain. Lipid droplets were abundant in conidia of the cst1Δ strains, but rapidly disappeared during appressorium formation. This misscheduled lipid degradation might be related to the failure of appressorium penetration in the cst1Δ strain.

Download Full-text