scholarly journals WRKY Transcription Factors in Nicotiana tabacum Modulate Plant Immunity against Whitefly via Interacting with MAPK Cascade Pathways

Insects ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Dan-Mei Yao ◽  
Chi Zou ◽  
Yan-Ni Shu ◽  
Shu-Sheng Liu
Keyword(s):  
Transcription Factors ◽  
Nicotiana Tabacum ◽  
Plant Defense ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Wrky Transcription Factors ◽  
Tobacco Plants ◽  
Mitogen Activated Protein ◽  
Phloem Feeding

WRKY transcription factors are key regulators of many plant processes, most notably coping with biotic and abiotic stresses. Recently, the function of WRKY in plant defense against phloem-feeding insects such as whitefly (Bemisia tabaci) has been brought to attention. In this study, we found that the expression levels of Nicotiana tabacum WRKY4, WRKY6 and WRKY10 were significantly upregulated when tobacco plants were infested with whiteflies or treated with salicylic acid. Compared to controls, whiteflies lived longer and laid more eggs on NtWRKY-silenced tobacco plants but performed less well on NtWRKY-overexpressing plants. The three NtWRKYs interacted with five mitogen-activated protein kinases (NtMAPKs) in vivo and in vitro. These results suggest that the WRKYs in tobacco positively modulate plant defense against whiteflies through interaction with the mitogen-activated protein kinase cascade (MAPK cascade) pathways, and thus provide new insights into plant defense against phloem-feeding insects.

scholarly journals JCPyV-Induced MAPK Signaling Activates Transcription Factors during Infection

2019 ◽  
Vol 20 (19) ◽  
pp. 4779 ◽  
Author(s):  
Jeanne K. DuShane ◽  
Colleen L. Mayberry ◽  
Michael P. Wilczek ◽  
Sarah L. Nichols ◽  
Melissa S. Maginnis
Keyword(s):  
Transcription Factors ◽  
Mapk Signaling ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Downstream Signaling ◽  
Dual Specificity ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Underlying Mechanisms

JC polyomavirus (JCPyV), a ubiquitous human pathogen, is the etiological agent of the fatal neurodegenerative disease progressive multifocal leukoencephalopathy (PML). Like most viruses, JCPyV infection requires the activation of host-cell signaling pathways in order to promote viral replication processes. Previous works have established the necessity of the extracellular signal-regulated kinase (ERK), the terminal core kinase of the mitogen-activated protein kinase (MAPK) cascade (MAPK-ERK) for facilitating transcription of the JCPyV genome. However, the underlying mechanisms by which the MAPK-ERK pathway becomes activated and induces viral transcription are poorly understood. Treatment of cells with siRNAs specific for Raf and MAP kinase kinase (MEK) targets proteins in the MAPK-ERK cascade, significantly reducing JCPyV infection. MEK, the dual-specificity kinase responsible for the phosphorylation of ERK, is phosphorylated at times congruent with early events in the virus infectious cycle. Moreover, a MAPK-specific signaling array revealed that transcription factors downstream of the MAPK cascade, including cMyc and SMAD4, are upregulated within infected cells. Confocal microscopy analysis demonstrated that cMyc and SMAD4 shuttle to the nucleus during infection, and nuclear localization is reduced when ERK is inhibited. These findings suggest that JCPyV induction of the MAPK-ERK pathway is mediated by Raf and MEK and leads to the activation of downstream transcription factors during infection. This study further defines the role of the MAPK cascade during JCPyV infection and the downstream signaling consequences, illuminating kinases as potential therapeutic targets for viral infection.

scholarly journals Positive and negative selection invoke distinct signaling pathways.

1996 ◽  
Vol 184 (1) ◽  
pp. 9-18 ◽  
Author(s):  
J Alberola-Ila ◽  
K A Hogquist ◽  
K A Swan ◽  
M J Bevan ◽  
R M Perlmutter
Keyword(s):  
T Cell ◽  
Positive Selection ◽  
Negative Selection ◽  
Mapk Pathway ◽  
Cell Receptor ◽  
Dominant Negative ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

During T cell development, interaction of the T cell receptor (TCR) with cognate ligands in the thymus may result in either maturation (positive selection) or death (negative selection). The intracellular pathways that control these opposed outcomes are not well characterized. We have generated mice expressing dominant-negative Ras (dnRas) and Mek-1 (dMek) transgenes simultaneously, either in otherwise normal animals, or in animals expressing a transgenic TCR, thereby permitting a comprehensive analysis of peptide-specific selection. In this system, thymocyte maturation beyond the CD4+8+ stage is blocked almost completely, whereas negative selection, assessed using an in vitro deletion protocol, is quantitatively intact. This suggests that activation of the mitogen-activated protein kinase (MAPK) cascade is necessary for positive selection, but irrelevant for negative selection. Generation of gamma/delta and of CD4-8- alpha/beta T cells proceeds normally despite blockade of the MAPK cascade. Hence, only cells that mature via conventional, TCR-mediated repertoire selection require activation of the MAPK pathway to complete their maturation.

scholarly journals Ras/Mitogen-Activated Protein Kinase Signaling Activates Ets-1 and Ets-2 by CBP/p300 Recruitment

2004 ◽  
Vol 24 (24) ◽  
pp. 10954-10964 ◽  
Author(s):  
Charles E. Foulds ◽  
Mary L. Nelson ◽  
Adam G. Blaszczak ◽  
Barbara J. Graves
Keyword(s):  
Transcription Factors ◽  
Protein Kinase ◽  
Direct Interaction ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Creb Binding Protein ◽  
Mitogen Activated Protein ◽  
P300 Binding

ABSTRACT Cell signaling affects gene expression by regulating the activity of transcription factors. Here, we report that mitogen-activated protein kinase (MAPK) phosphorylation of Ets-1 and Ets-2, at a conserved site N terminal to their Pointed (PNT) domains, resulted in enhanced transactivation by preferential recruitment of the coactivators CREB binding protein (CBP) and p300. We discovered this phosphorylation-augmented interaction in an unbiased affinity chromatography screen of HeLa nuclear extracts by using either mock-treated or ERK2-phosphorylated ETS proteins as ligands. Binding between purified proteins demonstrated a direct interaction. Both the phosphoacceptor site, which lies in an unstructured region, and the PNT domain were required for the interaction. Minimal regions that were competent for induced CBP/p300 binding in vitro also supported MAPK-enhanced transcription in vivo. CBP coexpression potentiated MEK1-stimulated Ets-2 transactivation of promoters with Ras-responsive elements. Furthermore, CBP and Ets-2 interacted in a phosphorylation-enhanced manner in vivo. This study describes a distinctive interface for a transcription factor-coactivator complex and demonstrates a functional role for inducible CBP/p300 binding. In addition, our findings decipher the mechanistic link between Ras/MAPK signaling and two specific transcription factors that are relevant to both normal development and tumorigenesis.

scholarly journals Identification of DNA response elements regulating expression of CCAAT/enhancer-binding protein (C/EBP) β and δ during early adipogenesis

2020 ◽  
Author(s):  
James E. Merrett ◽  
Tao Bo ◽  
Peter J. Psaltis ◽  
Christopher G. Proud
Keyword(s):  
Transcription Factors ◽  
Mitogen Activated Protein Kinase ◽  
Gene Promoters ◽  
Response Elements ◽  
Diet Induced Obesity ◽  
Adipose Tissue Depots ◽  
Mitogen Activated Protein ◽  
Prevalence Of Obesity ◽  
Functional Dna

AbstractGiven the high and increasing prevalence of obesity and associated disorders, such as type-2 diabetes, it is important to understand the mechanisms that regulate lipid storage and the differentiation of fat cells, a process termed adipogenesis. Using the well-established mouse 3T3-L1 in vitro model of adipogenesis, we refine how the induction of two key adipogenic transcription factors, CCAAT/enhancer-binding proteins (C/EBPs) β and δ are regulated during early adipogenesis. We identify, in the gene promoters of Cebpb and Cebpd, the DNA response elements responsible for binding transcription factors that are activated by cAMP or glucocorticoids. We also show that mitogen-activated protein kinase (MAPK)-interacting kinase 2 (MNK2; Mknk2), which plays a distinct role in diet-induced obesity, is induced during early adipogenesis and identify the functional DNA response elements responsible for regulating its expression. Mknk2 expression is maintained in differentiated 3T3-L1 adipocytes and is expressed at high levels across a range of mouse adipose tissue depots. Together, these new insights help to clarify the transcriptional program of early adipogenesis and identify Mknk2 as one of potentially many genes up-regulated during adipogenesis.

scholarly journals Mutational Analysis of STE5 in the Yeast Saccharomyces cerevisiae: Application of a Differential Interaction Trap Assay for Examining Protein-Protein Interactions

Genetics ◽  
1997 ◽  
Vol 147 (2) ◽  
pp. 479-492 ◽  
Author(s):  
Carla Inouye ◽  
Namrita Dhillon ◽  
Tim Durfee ◽  
Patricia C Zambryski ◽  
Jeremy Thorner
Keyword(s):  
Protein Interactions ◽  
Mutational Analysis ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Missense Mutations ◽  
Protein Protein Interactions ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mitogen Activated Protein

Ste5 is essential for the yeast mating pheromone response pathway and is thought to function as a scaffold that organizes the components of the mitogen-activated protein kinase (MAPK) cascade. A new method was developed to isolate missense mutations in Ste5 that differentially affect the ability of Ste5 to interact with either of two MAPK cascade constituents, the MEKK (Ste11) and the MEK (Ste7). Mutations that affect association with Ste7 or with Ste11 delineate discrete regions of Ste5 that are critical for each interaction. Co-immunoprecipitation analysis, examining the binding in vitro of Ste5 to Ste11, Ste7, Ste4 (G protein, β subunit), and Fus3 (MAPK), confirmed that each mutation specifically affects the interaction of Ste5 with only one protein. When expressed in a ste5Δ cell, mutant Ste5 proteins that are defective in their ability to interact with either Ste11 or Ste7 result in a markedly reduced mating proficiency. One mutation that clearly weakened (but did not eliminate) interaction of Ste5 with Ste7 permitted mating at wild-type efficiency, indicating that an efficacious signal is generated even when Ste5 associates with only a small fraction of (or only transiently with) Ste7. Ste5 mutants defective in association with Ste11 or Ste7 showed strong interallelic complementation when co-expressed, suggesting that the functional form of Ste5 in vivo is an oligomer.

scholarly journals Activation of a Novel Transcription Factor through Phosphorylation by WIPK, a Wound-Induced Mitogen-Activated Protein Kinase in Tobacco Plants

2005 ◽  
Vol 139 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Yun-Kiam Yap ◽  
Yutaka Kodama ◽  
Frank Waller ◽  
Kwi Mi Chung ◽  
Hirokazu Ueda ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Tobacco Plants ◽  
Mitogen Activated Protein

scholarly journals Targeting of p38 Mitogen-Activated Protein Kinases to MEF2 Transcription Factors

1999 ◽  
Vol 19 (6) ◽  
pp. 4028-4038 ◽  
Author(s):  
Shen-Hsi Yang ◽  
Alex Galanis ◽  
Andrew D. Sharrocks
Keyword(s):  
Transcription Factors ◽  
Transcriptional Activation ◽  
Cellular Response ◽  
Map Kinases ◽  
Biological Response ◽  
Extracellular Signals ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

ABSTRACT Mitogen-activated protein (MAP) kinase-mediated signalling to the nucleus is an important event in the conversion of extracellular signals into a cellular response. However, the existence of multiple MAP kinases which phosphorylate similar phosphoacceptor motifs poses a problem in maintaining substrate specificity and hence the correct biological response. Both the extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) subfamilies of MAP kinases use a second specificity determinant and require docking to their transcription factor substrates to achieve maximal substrate activation. In this study, we demonstrate that among the different MAP kinases, the MADS-box transcription factors MEF2A and MEF2C are preferentially phosphorylated and activated by the p38 subfamily members p38α and p38β2. The efficiency of phosphorylation in vitro and transcriptional activation in vivo of MEF2A and MEF2C by these p38 subtypes requires the presence of a kinase docking domain (D-domain). Furthermore, the D-domain from MEF2A is sufficient to confer p38 responsiveness on different transcription factors, and reciprocal effects are observed upon the introduction of alternative D-domains into MEF2A. These results therefore contribute to our understanding of signalling to MEF2 transcription factors and demonstrate that the requirement for substrate binding by MAP kinases is an important facet of three different subclasses of MAP kinases (ERK, JNK, and p38).

scholarly journals Cross-talk between IRAK-4 and the NADPH oxidase1

2007 ◽  
Vol 403 (3) ◽  
pp. 451-461 ◽  
Author(s):  
Sandrine Pacquelet ◽  
Jennifer L. Johnson ◽  
Beverly A. Ellis ◽  
Agnieszka A. Brzezinska ◽  
William S. Lane ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nadph Oxidase ◽  
P38 Mapk ◽  
Interleukin 1 ◽  
Mitogen Activated Protein Kinase ◽  
Free System ◽  
Mitogen Activated Protein ◽  
A Cell ◽  
Tlr4 Activation

Exposure of neutrophils to LPS (lipopolysaccharide) triggers their oxidative response. However, the relationship between the signalling downstream of TLR4 (Toll-like receptor 4) after LPS stimulation and the activation of the oxidase remains elusive. Phosphorylation of the cytosolic factor p47phox is essential for activation of the NADPH oxidase. In the present study, we examined the hypothesis that IRAK-4 (interleukin-1 receptor-associated kinase-4), the main regulatory kinase downstream of TLR4 activation, regulates the NADPH oxidase through phosphorylation of p47phox. We show that p47phox is a substrate for IRAK-4. Unlike PKC (protein kinase C), IRAK-4 phosphorylates p47phox not only at serine residues, but also at threonine residues. Target residues were identified by tandem MS, revealing a novel threonine-rich regulatory domain. We also show that p47phox is phosphorylated in granulocytes in response to LPS stimulation. LPS-dependent phosphorylation of p47phox was enhanced by the inhibition of p38 MAPK (mitogen-activated protein kinase), confirming that the kinase operates upstream of p38 MAPK. IRAK-4-phosphorylated p47phox activated the NADPH oxidase in a cell-free system, and IRAK-4 overexpression increased NADPH oxidase activity in response to LPS. We have shown that endogenous IRAK-4 interacts with p47phox and they co-localize at the plasma membrane after LPS stimulation, using immunoprecipitation assays and immunofluorescence microscopy respectively. IRAK-4 was activated in neutrophils in response to LPS stimulation. We found that Thr133, Ser288 and Thr356, targets for IRAK-4 phosphorylation in vitro, are also phosphorylated in endogenous p47phox after LPS stimulation. We conclude that IRAK-4 phosphorylates p47phox and regulates NADPH oxidase activation after LPS stimulation.

scholarly journals Role for the Ran Binding Protein, Mog1p, in Saccharomyces cerevisiae SLN1-SKN7 Signal Transduction

2004 ◽  
Vol 3 (6) ◽  
pp. 1544-1556 ◽  
Author(s):  
Jade Mei-Yeh Lu ◽  
Robert J. Deschenes ◽  
Jan S. Fassler
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Osmotic Response ◽  
Mitogen Activated Protein ◽  
Kinase Pathway

ABSTRACT Yeast Sln1p is an osmotic stress sensor with histidine kinase activity. Modulation of Sln1 kinase activity in response to changes in the osmotic environment regulates the activity of the osmotic response mitogen-activated protein kinase pathway and the activity of the Skn7p transcription factor, both important for adaptation to changing osmotic stress conditions. Many aspects of Sln1 function, such as how kinase activity is regulated to allow a rapid response to the continually changing osmotic environment, are not understood. To gain insight into Sln1p function, we conducted a two-hybrid screen to identify interactors. Mog1p, a protein that interacts with the yeast Ran1 homolog, Gsp1p, was identified in this screen. The interaction with Mog1p was characterized in vitro, and its importance was assessed in vivo. mog1 mutants exhibit defects in SLN1-SKN7 signal transduction and mislocalization of the Skn7p transcription factor. The requirement for Mog1p in normal localization of Skn7p to the nucleus does not fully account for the mog1-related defects in SLN1-SKN7 signal transduction, raising the possibility that Mog1p may play a role in Skn7 binding and activation of osmotic response genes.

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