scholarly journals The Biotrophic, Non-Appressorium-Forming Grass Pathogen Claviceps purpurea Needs a Fus3/Pmk1 Homologous Mitogen-Activated Protein Kinase for Colonization of Rye Ovarian Tissue

2002 ◽  
Vol 15 (4) ◽  
pp. 303-312 ◽  
Author(s):  
G. Mey ◽  
B. Oeser ◽  
M. H. Lebrun ◽  
P. Tudzynski
Keyword(s):  
Map Kinase ◽  
Magnaporthe Grisea ◽  
Ovarian Tissue ◽  
Gene Replacement ◽  
Mitogen Activated Protein Kinase ◽  
Claviceps Purpurea ◽  
Obvious Effect ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Detail Loss

Claviceps purpurea is a common pathogen of a wide range of grasses and cereals that is able to establish a stable, balanced interaction with its host plant and is considered a biotroph. It does not form special penetration structures such as appressoria. To study the signaling processes involved in this special host-pathogen interaction, we have cloned a gene, cpmk1, encoding a mitogen-activated protein (MAP) kinase that shows significant homology to Fus3 of Saccharomyces cerevisiae and to pmk1 of Magnaporthe grisea. Using a gene-replacement approach, we isolated a Δcpmk1 mutant and characterized it in detail. Loss of CPMK1 has no obvious effect on vegetative properties (such as growth rate, morphology, and conidia formation); however, infection tests on rye show that the mutant is unable to colonize rye tissue, i.e., it appears to be completely nonpathogenic. Complementation of the mutant with a wild-type copy of cpmk1 fully restores its pathogenicity, confirming that this MAP kinase is essential for infection of rye by C. purpurea. Transformation of the Δpmk1 mutant of M. grisea with a complete copy of cpmk1 (including the C. purpurea promoter) fully restored its ability to form appressoria and its pathogenicity on barley. Although both fungi drastically differ in their pathogenic strategies, this result indicates that the signal pathway involving CPMK1 is highly conserved.

scholarly journals Osmoregulation and Fungicide Resistance: the Neurospora crassa os-2 Gene Encodes a HOG1 Mitogen-Activated Protein Kinase Homologue

2002 ◽  
Vol 68 (2) ◽  
pp. 532-538 ◽  
Author(s):  
Yan Zhang ◽  
Randy Lamm ◽  
Christian Pillonel ◽  
Stephen Lam ◽  
Jin-Rong Xu
Keyword(s):  
Map Kinase ◽  
Neurospora Crassa ◽  
Fungicide Resistance ◽  
Point Mutations ◽  
Gene Replacement ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
High Osmolarity ◽  
Mitogen Activated Protein ◽  
Sib Selection

ABSTRACT Neurospora crassa osmosensitive (os) mutants are sensitive to high osmolarity and therefore are unable to grow on medium containing 4% NaCl. We found that os-2 and os-5 mutants were resistant to the phenylpyrrole fungicides fludioxonil and fenpiclonil. To understand the relationship between osmoregulation and fungicide resistance, we cloned the os-2 gene by using sib selection. os-2 encodes a putative mitogen-activated protein (MAP) kinase homologous to HOG1 and can complement the osmosensitive phenotype of a Saccharomyces cerevisiae hog1 mutant. We sequenced three os-2 alleles and found that all of them were null with either frameshift or nonsense point mutations. An os-2 gene replacement mutant also was generated and was sensitive to high osmolarity and resistant to phenylpyrrole fungicides. Conversely, os-2 mutants transformed with the wild-type os-2 gene could grow on media containing 4% NaCl and were sensitive to phenylpyrrole fungicides. Fludioxonil stimulated intracellular glycerol accumulation in wild-type strains but not in os-2 mutants. Fludioxonil also caused wild-type conidia and hyphal cells to swell and burst. These results suggest that the hyperosmotic stress response pathway of N. crassa is the target of phenylpyrrole fungicides and that fungicidal effects may result from a hyperactive os-2 MAP kinase pathway.

scholarly journals MST12 Regulates Infectious Growth But Not Appressorium Formation in the Rice Blast Fungus Magnaporthe grisea

2002 ◽  
Vol 15 (3) ◽  
pp. 183-192 ◽  
Author(s):  
Gyungsoon Park ◽  
Chaoyang Xue ◽  
Li Zheng ◽  
Stephen Lam ◽  
Jin-Rong Xu
Keyword(s):  
Transcription Factor ◽  
Rice Blast ◽  
Magnaporthe Grisea ◽  
Rice Blast Fungus ◽  
Gene Replacement ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Gene ◽  
Blast Fungus ◽  
Mitogen Activated Protein ◽  
Barley Leaves

In the rice blast fungus Magnaporthe grisea, a mitogen-activated protein kinase gene, PMK1, is known to regulate ap-pressorium formation and infectious hyphae growth. Since PMK1 is homologous to the FUS3 and KSS1 genes that regulate the transcription factor STE12 in yeast, we functionally characterized the STE12 homologue in M. grisea (MST12). A polymerase chain reaction-based approach was used to isolate the MST12 gene that is homologous to yeast STE12. Four mst12 deletion mutants were isolated by gene replacement. No obvious defect in vegetative growth, conidiation, or conidia germination was observed in mst12 mutants. However, mst12 mutants were nonpathogenic on rice and barley leaves. In contrast to pmk1 mutants that did not form appressoria, mst12 mutants produced typical dome-shaped and melanized appressoria. However, the ap-pressoria formed by mst12 mutants failed to penetrate onion epidermal cells. When inoculated through wound sites, mst12 mutants failed to cause spreading lesions and appeared to be defective in infectious growth. These data indicate that MST12 may function downstream of PMK1 to regulate genes involved in infectious hyphae growth. A transcription factor or factors other than MST12 must exist in M. grisea and function downstream from PMK1 for ap-pressorium formation.

Comparative Study on Mitogen Activated Protein Kinase of Plasmodium Species by Using in silico Method

2012 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Mohd Fakharul Zaman Raja Yahya ◽  
Hasidah Mohd Sidek
Keyword(s):  
Amino Acid ◽  
In Silico ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Plasmodium Species ◽  
Mitogen Activated Protein Kinase ◽  
Multiple Sequence ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Human Plasmodium

Malaria parasites, Plasmodium can infect a wide range of hosts including humans and rodents. There are two copies of mitogen activated protein kinases (MAPKs) in Plasmodium, namely MAPK1 and MAPK2. The MAPKs have been studied extensively in the human Plasmodium, P. falciparum. However, the MAPKs from other Plasmodium species have not been characterized and it is therefore the premise of presented study to characterize the MAPKs from other Plasmodium species-P. vivax, P. knowlesi, P. berghei, P. chabaudi and P.yoelli using a series of publicly available bioinformatic tools. In silico data indicates that all Plasmodium MAPKs are nuclear-localized and contain both a nuclear localization signal (NLS) and a Leucine-rich nuclear export signal (NES). The activation motifs of TDY and TSH were found to be fully conserved in Plasmodium MAPK1 and MAPK2, respectively. The detailed manual inspection of a multiple sequence alignment (MSA) construct revealed a total of 17 amino acid stack patterns comprising of different amino acids present in MAPKJ and MAPK2 respectively, with respect to rodent and human Plasmodia. It is proposed that these amino acid stack patterns may be useful in explaining the disparity between rodent and human Plasmodium MAPKs. 

scholarly journals Signaling through mitogen-activated protein kinase and Rac/Rho does not duplicate the effects of activated Ras on skeletal myogenesis.

1997 ◽  
Vol 17 (7) ◽  
pp. 3547-3555 ◽  
Author(s):  
M B Ramocki ◽  
S E Johnson ◽  
M A White ◽  
C L Ashendel ◽  
S F Konieczny ◽  
...  
Keyword(s):  
Map Kinase ◽  
Signaling Pathways ◽  
Transcriptional Activation ◽  
Intracellular Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Ras Signaling ◽  
Negative Effects ◽  
Intracellular Signaling Pathway ◽  
Helix Loop Helix ◽  
Mitogen Activated Protein

The ability of basic helix-loop-helix muscle regulatory factors (MRFs), such as MyoD, to convert nonmuscle cells to a myogenic lineage is regulated by numerous growth factor and oncoprotein signaling pathways. Previous studies have shown that H-Ras 12V inhibits differentiation to a skeletal muscle lineage by disrupting MRF function via a mechanism that is independent of the dimerization, DNA binding, and inherent transcriptional activation properties of the proteins. To investigate the intracellular signaling pathway(s) that mediates the inhibition of MRF-induced myogenesis by oncogenic Ras, we tested two transformation-defective H-Ras 12V effector domain variants for their ability to alter terminal differentiation. H-Ras 12V,35S retains the ability to activate the Raf/MEK/mitogen-activated protein (MAP) kinase cascade, whereas H-Ras 12V,40C is unable to interact directly with Raf-1 yet still influences other signaling intermediates, including Rac and Rho. Expression of each H-Ras 12V variant in C3H10T1/2 cells abrogates MyoD-induced activation of the complete myogenic program, suggesting that MAP kinase-dependent and -independent Ras signaling pathways individually block myogenesis in this model system. However, additional studies with constitutively activated Rac1 and RhoA proteins revealed no negative effects on MyoD-induced myogenesis. Similarly, treatment of Ras-inhibited myoblasts with the MEK1 inhibitor PD98059 revealed that elevated MAP kinase activity is not a significant contributor to the H-Ras 12V effect. These data suggest that an additional Ras pathway, distinct from the well-characterized MAP kinase and Rac/Rho pathways known to be important for the transforming function of activated Ras, is primarily responsible for the inhibition of myogenesis by H-Ras 12V.

Functional Role of p38 Mitogen Activated Protein Kinase in Platelet Activation induced by a Thromboxane A2 Analogue and by 8-iso-prostaglandin F2 α

2002 ◽  
Vol 87 (05) ◽  
pp. 888-898 ◽  
Author(s):  
Stefania Gaino ◽  
Valeria Zuliani ◽  
Rosa Tommasoli ◽  
Donatella Benati ◽  
Riccardo Ortolani ◽  
...  
Keyword(s):  
Map Kinase ◽  
Platelet Activation ◽  
Tyrosine Kinases ◽  
Actin Polymerization ◽  
Shape Change ◽  
Specific Inhibitor ◽  
P38 Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation

SummaryWe investigated similarities in the signaling pathways elicited by the F2 isoprostane 8-iso-PGF2α and by low doses of U46619 to induce platelet activation. Both 0.01-0.1 µmol/L U46619 and 0.01-1 µmol/L 8-isoPGF2α triggered shape change and filopodia extension, as well as adhesion to immobilized fibrinogen of washed platelets. At these doses the two platelet agonists failed to trigger secretion and aggregation, which were however induced by higher doses of U46619 (0.1-1 µmol/L). SB203580 (1-10 µmol/L), a specific inhibitor of the p38 mitogen activated protein (MAP) kinase blunted platelet shape change and adhesion induced by 0.05-1 µmol/L 8-iso-PGF2α and by 0.01 µmol/L U46619. These platelet responses were also inhibited by 20 µmol/L cytochalasin D, an inhibitor of actin polymerization, and 50 µmol/L piceatannol, an inhibitor of the Syk tyrosine kinases. Both 8-iso-PGF2α and U46619-induced p38 MAP kinase phosphorylation in suspended platelets and this was inhibited by piceatannol, indicating that Syk activation occurs upstream p38 MAP kinase phosphorylation. These findings suggest that the signaling pathway triggered by both 8-iso-PGF2α and low concentrations of U46619 to induce platelet adhesion and shape change implicates Syk, the p38 MAP kinase, and actin polymerization.

Involvement of Ras/MAP Kinase in the Regulation of Ca2+ Channels in Adult Bullfrog Sympathetic Neurons by Nerve Growth Factor

1998 ◽  
Vol 80 (3) ◽  
pp. 1352-1361 ◽  
Author(s):  
Saobo Lei ◽  
William F. Dryden ◽  
Peter A. Smith
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Map Kinase ◽  
Kinase Inhibitors ◽  
Sympathetic Neurons ◽  
Mitogen Activated Protein Kinase ◽  
Nerve Growth ◽  
Channel Current ◽  
Mitogen Activated Protein

Lei, Saobo, William F. Dryden, and Peter A. Smith. Involvement of Ras/MAP kinase in the regulation of Ca2+ channels in adult bullfrog sympathetic neurons by nerve growth factor. J. Neurophysiol. 80: 1352–1361, 1998. The cellular mechanisms that underlie nerve growth factor (NGF) induced increase in Ca2+-channel current in adult bullfrog sympathetic B-neurons were examined by whole cell recording techniques. Cells were maintained at low density in neuron-enriched, defined-medium, serum-free tissue culture for 6 days in the presence or absence of NGF (200 ng/ml). The increase in Ba2+ current ( I Ba) density induced by NGF was attenuated by the RNA synthesis inhibitor cordycepin (20 μM), by the DNA transcription inhibitor actinomycin D (0.01 μg/ml), by inhibitors of Ras isoprenylation (perillic acid 0.1–1.0 mM or α-hydroxyfarnesylphosphonic acid 10–100 μM), by tyrosine kinase inhibitors genistein (20 μM) or lavendustin A (1 μM), and by PD98059 (10–100 μM), an inhibitor of mitogen-activated protein kinase kinase. Inhibitors of the phosphatidylinositol 3-kinase (PI3K) pathway (wortmannin, 100 nM, or LY29400, 100 μM) were ineffective as were inhibitors of phospholipase Cγ (U73122 or neomycin, both 100 μM). The effect of NGF persisted in Ca2+-free medium that contained 1.8 mM Mg2+ and 2 mM ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid. It was mimicked by a Trk antibody that was capable of inducing neurite outgrowth in explant cultures of bullfrog sympathetic ganglion. Antibodies raised against the low-affinity p75 neurotrophin receptor were ineffective in blocking the effect of NGF on I Ba. These results suggest that NGF-induced increase in Ca2+ channel current in adult sympathetic neurons results, at least in part, from new channel synthesis after Trk activation of Ras and mitogen activated protein kinase by a mechanism that is independent of extracellular Ca2+.

scholarly journals Ras Mutation Impairs Epithelial Barrier Function to a Wide Range of Nonelectrolytes

2005 ◽  
Vol 16 (12) ◽  
pp. 5538-5550 ◽  
Author(s):  
James M. Mullin ◽  
James M. Leatherman ◽  
Mary Carmen Valenzano ◽  
Erika Rendon Huerta ◽  
Jon Verrechio ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Mitogen Activated Protein Kinase ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Downstream Effects ◽  
Extracellular Signal ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Protein Kinase Signaling ◽  
Kinase Signaling Pathway

Although ras mutations have been shown to affect epithelial architecture and polarity, their role in altering tight junctions remains unclear. Transfection of a valine-12 mutated ras construct into LLC-PK1 renal epithelia produces leakiness of tight junctions to certain types of solutes. Transepithelial permeability of d-mannitol increases sixfold but transepithelial electrical resistance increases >40%. This indicates decreased paracellular permeability to NaCl but increased permeability to nonelectrolytes. Permeability increases to d-mannitol (Mr 182), polyethylene glycol (Mr 4000), and 10,000-Mr methylated dextran but not to 2,000,000-Mr methylated dextran. This implies a “ceiling” on the size of solutes that can cross a ras-mutated epithelial barrier and therefore that the increased permeability is not due to loss of cells or junctions. Although the abundance of claudin-2 declined to undetectable levels in the ras-overexpressing cells compared with vector controls, levels of occludin and claudins 1, 4, and 7 increased. The abundance of claudins-3 and -5 remained unchanged. An increase in extracellular signal-regulated kinase-2 phosphorylation suggests that the downstream effects on the tight junction may be due to changes in the mitogen-activated protein kinase signaling pathway. These selective changes in permeability may influence tumorigenesis by the types of solutes now able to cross the epithelial barrier.

scholarly journals MAP Kinase OsMEK2 and OsMPK1 Signaling for Ferroptotic Cell Death in Rice-Magnaporthe oryzae Interactions

2020 ◽  
Author(s):  
Sarmina Dangol ◽  
Raksha Singh ◽  
Khoa Nam Nguyen ◽  
Yafei Chen ◽  
Juan Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Map Kinase ◽  
Signaling Pathways ◽  
Magnaporthe Oryzae ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Microbial Pathogens ◽  
Blast Disease ◽  
Related Cell ◽  
Mitogen Activated Protein

ABSTRACTMitogen-activated protein kinase (MAPK) signaling is required for plant cell death responses to invading microbial pathogens. Ferric ions and reactive oxygen species (ROS) accumulate in rice (Oryza sativa) tissues undergoing cell death during Magnaporthe oryzae infection. Here, we report that rice MAP kinase (OsMEK2 and OsMPK1) signaling cascades are involved in iron- and ROS-dependent ferroptotic cell death responses of rice to M. oryzae infection. OsMEK2 interacted with OsMPK1 in the cytoplasm, and OsMPK1 moved from the cytoplasm into the nucleus to bind to the OsWRKY90 transcription factor. OsMEK2 expression may trigger OsMPK1-OsWRKY90 signaling pathways in the nucleus. Avirulent M. oryzae infection in ΔOsmek2 mutant rice did not trigger iron and ROS accumulation and lipid peroxidation, and also downregulated OsMPK1, OsWRKY90, OsRbohB, and OsPR-1b expression. However, OsMEK2 overexpression induced ROS-and iron-dependent cell death in rice during M. oryzae infection. The downstream MAP kinase (OsMPK1) overexpression induced ROS- and iron-dependent ferroptotic cell death in the compatible rice-M. oryzae interaction. These data suggest that the OsMEK2-OsMPK1-OsWRKY90 signaling cascade is involved in the ferroptotic cell death in rice. The small-molecule inducer erastin triggered iron- and lipid ROS-dependent, but OsMEK2-independent, ferroptotic cell death in ΔOsmek2 mutant plants during M. oryzae infection. Disease-related cell death was lipid ROS-dependent and iron-independent in the ΔOsmek2 mutant plants. These combined results suggest that OsMEK2 and OsMPK1 expression positively regulates iron- and ROS-dependent ferroptotic cell death via OsMEK2-OsMPK1-OsWRKY90 signaling pathways, and blast disease (susceptibility)-related cell death was ROS-dependent but iron-independent in rice-M. oryzae interactions.

scholarly journals Role of Mitogen-Activated Protein Kinase Pathway in Prostaglandin F2α-Induced Rat Puerperal Uterine Contraction

Endocrinology ◽  
1997 ◽  
Vol 138 (8) ◽  
pp. 3103-3111 ◽  
Author(s):  
Masahide Ohmichi ◽  
Koji Koike ◽  
Akiko Kimura ◽  
Kanji Masuhara ◽  
Hiromasa Ikegami ◽  
...  
Keyword(s):  
Map Kinase ◽  
Uterine Contraction ◽  
Prostaglandin F2α ◽  
Mek Inhibitor ◽  
Biological Action ◽  
Mitogen Activated Protein Kinase ◽  
Myometrial Cells ◽  
Mitogen Activated Protein ◽  
Kinase Pathway

Abstract In this study, prostaglandin (PG) F2α was found to activate mitogen-activated protein (MAP) kinase and MAP kinase kinase (MEK) in cultured rat puerperal uterine myometrial cells. PGF2α stimulation also led to an increase in phosphorylation of raf-1, son of sevenless (SOS), and Shc. Furthermore, we examined the mechanism by which PGF2α induced MAP kinase phosphorylation. Both pertussis toxin (10 ng/ml), which inactivates Gi/Go proteins, and expression of a peptide derived from the carboxyl terminus of the β-adrenergic receptor kinase 1 (βARK1), which specifically blocks signaling mediated by the βγ subunits of G proteins, blocked the PGF2α-induced activation of MAP kinase. Ritodrine (1 μm), which is known to relax uterine muscle contraction, attenuated PGF2α-induced tyrosine phosphorylation of MAP kinase. Moreover, to examine the role of MAP kinase pathway in uterine contraction, an inhibitor of MEK activity, PD098059, was used. Although MEK inhibitor had no effect on PGF2α-induced calcium mobilization, this inhibitor partially inhibited PGF2α-induced uterine contraction. These results provide evidence that PGF2α stimulates the MAP kinase signaling pathway in cultured rat puerperal uterine myometrial cells through Gβγ protein, suggesting that this new pathway may play an important role in the biological action of PGF2α on these cells.

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