Characterization of the ERK homologue CpMK2 from the chestnut blight fungus Cryphonectria parasitica

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1349-1358 ◽  
Author(s):  
Eun-Sil Choi ◽  
Hea-Jong Chung ◽  
Myoung-Ju Kim ◽  
Seung-Moon Park ◽  
Byeong-Jin Cha ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Cryphonectria Parasitica ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Growth Defects ◽  
Chestnut Blight Fungus ◽  
Phosphorylation Level ◽  
Solid Media ◽  
Mitogen Activated Protein ◽  
Hypovirulent Strain

The Cryphonectria parasitica gene cpmk2, which encodes a mitogen-activated protein kinase belonging to the yeast extracellular signalling-regulated kinase (YERK1) subfamily, was isolated and its biological function was examined. Disruption of cpmk2 resulted in impaired pigmentation and abolished conidiation. Growth defects were observed in the cpmk2 mutant grown on solid plates, but growth of the mutant appeared normal in liquid media, including EP complete and PD broth, suggesting that the cpmk2 gene is involved in sensing and responding to growth conditions. The mutant's production of laccase, as measured by the size of the coloured area produced on tannic-acid-supplemented plates, was significantly reduced compared with the wild-type, but the intensity of the coloured area was unchanged, suggesting that the reduced laccase activity was owing to reduced growth on solid media rather than transcriptional downregulation. A dramatic reduction observed in the canker area produced by the cpmk2 mutant compared with the wild-type, even more severe than that of a hypovirulent strain, can also be ascribed to defective growth on solid surfaces rather than to impairments in a virulence factor(s). Downregulation of the pheromone gene Mf2/1 was also observed in the mutant, indicating a possible explanation for the regulation of the pheromone precursor gene in filamentous fungi and suggesting the presence of the yeast-like pheromone-responsive pathway in C. parasitica. Immunoblot analyses revealed that the phosphorylation level of CpMK2 increased in both virus-free and virus-containing strains in liquid cultures of up to 5 days old and decreased in older cultures. Moreover, the CpMK2 phosphorylation level increased in both strains after transfer from liquid to solid medium. However, levels of phosphorylated CpMK2 were similar in the two strains, suggesting that CpMK2, unlike CpMK1, is not under the direct control of a hypovirus.

scholarly journals A Mutant of the Bck1 Homolog from Cryphonectria parasitica Resulted in Sectorization with an Impaired Pathogenicity

2016 ◽  
Vol 29 (4) ◽  
pp. 268-276 ◽  
Author(s):  
Jung-Mi Kim ◽  
Joong-Gi Lee ◽  
Suk-Hyun Yun ◽  
Kum-Kang So ◽  
Yo-Han Ko ◽  
...  
Keyword(s):  
Cell Wall ◽  
Signal Transduction Pathway ◽  
Cryphonectria Parasitica ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Null Mutant ◽  
Genetic Changes ◽  
Chestnut Blight Fungus ◽  
Mitogen Activated Protein ◽  
Protein Kinase Kinase

CpBck1, an ortholog of the cell-wall integrity mitogen-activated protein kinase kinase kinase of Saccharomyces cerevisiae, was cloned and characterized from the chestnut blight fungus Cryphonectria parasitica. The CpBck1-null mutant displayed cell wall integrity–related phenotypic changes such as abnormal cell morphology and wall formation and hypersensitivity to cell wall-disrupting agents. In addition, the mutant showed severely retarded growth without any sign of normal development, such as hyphal differentiation, conidiation, or pigmentation. As the culture proceeded, the mutant colony showed sporadic sectorization. Once sectored, the sectored phenotype of robust mycelial growth without differentiation was stably inherited. Compared with the wild type, both the parental CpBck1-null mutant and the sectored progeny exhibited marked impaired virulence. The present study revealed that a mutation in a signaling pathway component related to cell-wall integrity resulted in sporadic sectorization and these sectored phenotypes were stably inherited, suggesting that this signal transduction pathway is implicated in adaptive genetic changes for sectorization.

scholarly journals TRAF6-Dependent Mitogen-Activated Protein Kinase Activation Differentially Regulates the Production of Interleukin-12 by Macrophages in Response to Toxoplasma gondii

2004 ◽  
Vol 72 (10) ◽  
pp. 5662-5667 ◽  
Author(s):  
Nicola J. Mason ◽  
Jim Fiore ◽  
Takashi Kobayashi ◽  
Katherine S. Masek ◽  
Yongwon Choi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Toxoplasma Gondii ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Interleukin 12 ◽  
Wild Type ◽  
Kinase Activation ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

ABSTRACT The production of interleukin-12 (IL-12) is critical to the development of innate and adaptive immune responses required for the control of intracellular pathogens. Many microbial products signal through Toll-like receptors (TLR) and activate NF-κB family members that are required for the production of IL-12. Recent studies suggest that components of the TLR pathway are required for the production of IL-12 in response to the parasite Toxoplasma gondii; however, the production of IL-12 in response to this parasite is independent of NF-κB activation. The adaptor molecule TRAF6 is involved in TLR signaling pathways and associates with serine/threonine kinases involved in the activation of both NF-κB and mitogen-activated protein kinase (MAPK). To elucidate the intracellular signaling pathways involved in the production of IL-12 in response to soluble toxoplasma antigen (STAg), wild-type and TRAF6−/− mice were inoculated with STAg, and the production of IL-12(p40) was determined. TRAF6−/− mice failed to produce IL-12(p40) in response to STAg, and TRAF6−/− macrophages stimulated with STAg also failed to produce IL-12(p40). Studies using Western blot analysis of wild-type and TRAF6−/− macrophages revealed that stimulation with STAg resulted in the rapid TRAF6-dependent phosphorylation of p38 and extracellular signal-related kinase, which differentially regulated the production of IL-12(p40). The studies presented here demonstrate for the first time that the production of IL-12(p40) in response to toxoplasma is dependent upon TRAF6 and p38 MAPK.

scholarly journals A single amino acid substitution (N297A) in the conserved NPXXY sequence of the human N-formyl peptide receptor results in inhibition of desensitization and endocytosis, and a dose-dependent shift in p42/44 mitogen-activated protein kinase activation and chemotaxis

2000 ◽  
Vol 352 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Jeannie M. GRIPENTROG ◽  
Algirdas J. JESAITIS ◽  
Heini M. MIETTINEN
Keyword(s):  
Protein Kinase ◽  
Transmembrane Domain ◽  
Mitogen Activated Protein Kinase ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Mitogen Activated Protein ◽  
Dose Dependent Increase ◽  
Dose Dependent

The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis and stimulates the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase pathway. We have examined the functional effects of substitutions of a conserved aspartic acid residue in the second transmembrane domain (D71A) and of residues in the conserved NPXXY motif in the seventh transmembrane domain (N297A and Y301A). These mutated receptors, expressed in Chinese hamster ovary (CHO) cells, bind ligand with affinities similar to wild-type FPR, but the D71A mutant is uncoupled from G-protein [Miettinen, Mills, Gripentrog, Dratz, Granger and Jesaitis (1997) J. Immunol 159, 4045–4054]. In the present study, we show that both the D71A and N297A mutations resulted in defective endocytosis. The N297A substitution also prevented desensitization, as determined by intracellular calcium mobilization by sequential stimulation with ligand. In chemotaxis assays, the N297A mutation resulted in cell migration towards gradients of up to 100nM N-formyl-methionyl-leucyl-phenylalanine (fMLF), whereas cells expressing the wild-type FPR and the Y301A mutant were no longer chemotactically responsive at 10–100nM fMLF. Maximal activation of p42/44 MAPK occurred in CHO cells expressing wild-type FPR at 10nM–100nM fMLF, whereas cells expressing the N297A mutant showed a dose-dependent increase in the amount of phosphorylated p42/44 MAPK up to 1–10µM fMLF. Since the MAPK kinase inhibitor PD98059 blocked fMLF-induced chemotaxis, our results suggest that the dose-dependent increase in p42/44 MAPK activation may correlate with the increased chemotactic migration of N297A transfectants at 10nM–100nM fMLF.

Diverse Responses Are Involved in the Defence of Arabidopsis thaliana against Turnip Crinkle Virus

2013 ◽  
Vol 68 (3-4) ◽  
pp. 148-154 ◽  
Author(s):  
Hui Yang ◽  
Shu Yuan ◽  
Yi Luo ◽  
Ji Huang ◽  
Yang-Er Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Hormones ◽  
Plant Defence ◽  
Mitogen Activated Protein Kinase ◽  
Turnip Crinkle Virus ◽  
Wild Type ◽  
Antagonistic Action ◽  
Pathogenesis Related ◽  
Mitogen Activated Protein ◽  
Plant Pathogen Interactions

Plant hormones play pivotal roles as signals of plant-pathogen interactions. Here, we report that exogenous application of salicylic acid (SA), jasmonic acid (JA), ethephon (ETH), and abscisic acid (ABA) can reduce Turnip crinkle virus (TCV) accumulation in systemic leaves of Arabidopsis thaliana during early infection. SA and ABA are more efficient and confer a longer-lasting resistance against TCV than JA and ETH, and the plant hormones interact in effecting the plant defence. Synergistic actions of SA and JA, and SA and ET, and an antagonistic action of SA and ABA have been observed in the Arabidopsis-TCV interaction. ABA can down-regulate the expression of the pathogenesis-related genes PR1 and PDF1.2, and compared to the wild type, it drastically reduces TCV accumulation in NahG transgenic plants and the eds5-p1 mutant, both of which do not accumulate SA. This indicates that SA signaling negatively regulates the ABA-mediated defence. ABA-induced resistance against TCV is independent of SA. We also found that mitogen-activated protein kinase 5 (MPK5) may be involved in ABA-mediated defence. These results indicate that Arabidopsis can activate distinct signals to inhibit virus accumulation. Cooperative or antagonistic crosstalk between them is pivotal for establishing disease resistance. These results show potential to enhance the plant defence against viruses by manipulating diverse hormones.

scholarly journals RICK Promotes Inflammation and Lethality after Gram-Negative Bacterial Infection in Mice Stimulated with Lipopolysaccharide

2009 ◽  
Vol 77 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Jong-Hwan Park ◽  
Yun-Gi Kim ◽  
Gabriel Núñez
Keyword(s):  
Protein Kinase ◽  
Regulatory Protein ◽  
Mitogen Activated Protein Kinase ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Proinflammatory Response ◽  
Interacting Protein ◽  
Gram Negative ◽  
Mitogen Activated Protein

ABSTRACT RICK (receptor-interacting protein-like interacting caspase-like apoptosis regulatory protein kinase), a serine-threonine kinase, functions downstream of the pattern recognition receptors Nod1 and Nod2 to mediate NF-κB and mitogen-activated protein kinase (MAPK) activation in response to specific microbial stimuli. However, the function of RICK in the recognition and host defense of gram-negative bacteria remains poorly understood. We report here that infection of wild-type and RICK-deficient macrophages with Pseudomonas aeruginosa and Escherichia coli elicited comparable activation of NF-κB and MAPKs as well as secretion of proinflammatory cytokines. However, production of interleukin 6 (IL-6) and IL-1β induced by these gram-negative bacteria was impaired in RICK-deficient macrophages when the cells had previously been stimulated with lipopolysaccharide (LPS) or E. coli. The diminished proinflammatory response of RICK-deficient macrophages to bacteria was associated with reduced activation of NF-κB and MAPKs. Importantly, mutant mice deficient in RICK were less susceptible than wild-type mice to P. aeruginosa infection when the animals had previously been stimulated with LPS. The reduced lethality of RICK-deficient mice infected with P. aeruginosa was independent of pathogen clearance but was associated with diminished production of proinflammatory molecules in vivo. These results demonstrate that RICK contributes to the induction of proinflammatory responses and susceptibility to gram-negative bacteria after exposure to LPS, a condition that is associated with reduced Toll-like receptor signaling.

scholarly journals PKC1 Is Essential for Protection against both Oxidative and Nitrosative Stresses, Cell Integrity, and Normal Manifestation of Virulence Factors in the Pathogenic Fungus Cryptococcus neoformans

2008 ◽  
Vol 7 (10) ◽  
pp. 1685-1698 ◽  
Author(s):  
Kimberly J. Gerik ◽  
Sujit R. Bhimireddy ◽  
Jan S. Ryerse ◽  
Charles A. Specht ◽  
Jennifer K. Lodge
Keyword(s):  
Cell Wall ◽  
Nitrosative Stress ◽  
Pathogenic Fungus ◽  
Fungal Growth ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Wild Type ◽  
Pathway Activation ◽  
Mitogen Activated Protein ◽  
Kinase Cascade

ABSTRACT Cell wall integrity is crucial for fungal growth, survival, and pathogenesis. Responses to environmental stresses are mediated by the highly conserved Pkc1 protein and its downstream components. In this study, we demonstrate that both oxidative and nitrosative stresses activate the PKC1 cell integrity pathway in wild-type cells, as measured by phosphorylation of Mpk1, the terminal protein in the PKC1 phosphorylation cascade. Furthermore, deletion of PKC1 shows that this gene is essential for defense against both oxidative and nitrosative stresses; however, other genes involved directly in the PKC1 pathway are dispensable for protection against these stresses. This suggests that Pkc1 may have multiple and alternative functions other than activating the mitogen-activated protein kinase cascade from a “top-down” approach. Deletion of PKC1 also causes osmotic instability, temperature sensitivity, severe sensitivity to cell wall-inhibiting agents, and alterations in capsule and melanin. Furthermore, the vital cell wall components chitin and its deacetylated form chitosan appear to be mislocalized in a pkc1Δ strain, although this mutant contains wild-type levels of both of these polymers. These data indicate that loss of Pkc1 has pleiotropic effects because it is central to many functions either dependent on or independent of PKC1 pathway activation. Notably, this is the first time that Pkc1 has been implicated in protection against nitrosative stress in any organism.

scholarly journals The AngFus3 Mitogen-Activated Protein Kinase Controls Hyphal Differentiation and Secondary Metabolism in Aspergillus niger

2015 ◽  
Vol 14 (6) ◽  
pp. 602-615 ◽  
Author(s):  
Bert-Ewald Priegnitz ◽  
Ulrike Brandt ◽  
Khomaizon A. K. Pahirulzaman ◽  
Jeroen S. Dickschat ◽  
André Fleißner
Keyword(s):  
Aspergillus Niger ◽  
Map Kinase ◽  
Secondary Metabolism ◽  
Filamentous Fungi ◽  
Cell Types ◽  
Growth Conditions ◽  
Mitogen Activated Protein Kinase ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Upstream Kinase

ABSTRACTAdaptation to a changing environment is essential for the survival and propagation of sessile organisms, such as plants or fungi. Filamentous fungi commonly respond to a worsening of their growth conditions by differentiation of asexually or sexually produced spores. The formation of these specialized cell types is, however, also triggered as part of the general life cycle by hyphal age or density. Spores typically serve for dispersal and, therefore, translocation but can also act as resting states to endure times of scarcity. Eukaryotic differentiation in response to environmental and self-derived signals is commonly mediated by three-tiered mitogen-activated protein (MAP) kinase signaling cascades. Here, we report that the MAP kinase Fus3 of the black moldAspergillus niger(AngFus3) and its upstream kinase AngSte7 control vegetative spore formation and secondary metabolism. Mutants lacking these kinases are defective in conidium induction in response to hyphal density but are fully competent in starvation-induced sporulation, indicating that conidiation inA. nigeris triggered by various independent signals. In addition, the mutants exhibit an altered profile of volatile metabolites and secrete dark pigments into the growth medium, suggesting a dysregulation of the secondary metabolism. By assigning the AngFus3 MAP kinase pathway to the transduction of a potentially self-derived trigger, this work contributes to the unraveling of the intricate signaling networks controlling fungal differentiation. Moreover, our data further support earlier observations that differentiation and secondary metabolism are tightly linked in filamentous fungi.

scholarly journals Concerted Activity of Tyrosine Phosphatase SHP-2 and Focal Adhesion Kinase in Regulation of Cell Motility

1999 ◽  
Vol 19 (4) ◽  
pp. 3125-3135 ◽  
Author(s):  
Santos Mañes ◽  
Emilia Mira ◽  
Concepción Gómez-Mouton ◽  
Zhizuang Joe Zhao ◽  
Rosa Ana Lacalle ◽  
...  
Keyword(s):  
Cell Migration ◽  
Protein Kinase ◽  
Cell Motility ◽  
Focal Adhesion ◽  
Tyrosine Phosphatase ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Igf I ◽  
Mitogen Activated Protein ◽  
Mcf 7

ABSTRACT The coordinated interplay of substrate adhesion and deadhesion is necessary for cell motility. Using MCF-7 cells, we found that insulin-like growth factor I (IGF-I) induces the adhesion of MCF-7 to vitronectin and collagen in a dose- and time-dependent manner, suggesting that IGF-I triggers the activation of different integrins. On the other hand, IGF-I promotes the association of insulin receptor substrate 1 with the focal adhesion kinase (FAK), paxillin, and the tyrosine phosphatase SHP-2, resulting in FAK and paxillin dephosphorylation. Abrogation of SHP-2 catalytic activity with a dominant-negative mutant (SHP2-C>S) abolishes IGF-I-induced FAK dephosphorylation, and cells expressing SHP2-C>S show reduced IGF-I-stimulated chemotaxis compared with either mock- or SHP-2 wild-type-transfected cells. This impairment of cell migration is recovered by reintroduction of a catalytically active SHP-2. Interestingly, SHP-2-C>S cells show a larger number of focal adhesion contacts than wild-type cells, suggesting that SHP-2 activity participates in the integrin deactivation process. Although SHP-2 regulates mitogen-activated protein kinase activity, the mitogen-activated protein kinase kinase inhibitor PD-98059 has only a marginal effect on MCF-7 cell migration. The role of SHP-2 as a general regulator of cell chemotaxis induced by other chemotactic agents and integrins is discussed.

scholarly journals Activation of the Mitogen-activated Protein Kinase, Slt2p, at Bud Tips Blocks a Late Stage of Endoplasmic Reticulum Inheritance in Saccharomyces cerevisiae

2010 ◽  
Vol 21 (10) ◽  
pp. 1772-1782 ◽  
Author(s):  
Xia Li ◽  
Yunrui Du ◽  
Steven Siegel ◽  
Susan Ferro-Novick ◽  
Peter Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Protein Phosphatase ◽  
Normal Growth ◽  
Growth Conditions ◽  
Mitogen Activated Protein Kinase ◽  
Mitochondrial Inheritance ◽  
Daughter Cells ◽  
Late Step ◽  
Mitogen Activated Protein

Inheritance of the endoplasmic reticulum (ER) requires Ptc1p, a type 2C protein phosphatase of Saccharomyces cerevisiae . Genetic analysis indicates that Ptc1p is needed to inactivate the cell wall integrity (CWI) MAP kinase, Slt2p. Here we show that under normal growth conditions, Ptc1p inactivates Slt2p just as ER tubules begin to spread from the bud tip along the cortex. In ptc1Δ cells, the propagation of cortical ER from the bud tip to the periphery of the bud is delayed by hyperactivation of Slt2p. The pool of Slt2p that controls ER inheritance requires the CWI pathway scaffold, Spa2p, for its retention at the bud tip, and a mutation within Slt2p that prevents its association with the bud tip blocks its role in ER inheritance. These results imply that Slt2p inhibits a late step in ER inheritance by phosphorylating a target at the tip of daughter cells. The PI4P5-kinase, Mss4p, is an upstream activator of this pool of Slt2p. Ptc1p-dependant inactivation of Slt2p is also needed for mitochondrial inheritance; however, in this case, the relevant pool of Slt2p is not at the bud tip.

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