scholarly journals The Coiled-Coil and Leucine-Rich Repeat Domain of the Potyvirus Resistance Protein Pvr4 Has a Distinct Role in Signaling and Pathogen Recognition

2018 ◽  
Vol 31 (9) ◽  
pp. 906-913 ◽  
Author(s):  
Saet-Byul Kim ◽  
Hye-Young Lee ◽  
Eun-Hye Choi ◽  
Eunsook Park ◽  
Ji-Hyun Kim ◽  
...  
Keyword(s):  
Cell Death ◽  
Coiled Coil ◽  
Mitogen Activated Protein Kinase ◽  
Protein Signaling ◽  
Death Domain ◽  
Leucine Rich Repeat ◽  
Domain Swap ◽  
Mitogen Activated Protein ◽  
And Function ◽  
Lrr Domain

The pepper Pvr4 protein encoding coiled-coil (CC) nucleotide-binding (NB) leucine-rich repeat (LRR) (NLR) confer hypersensitive response (HR) to potyviruses, including Pepper mottle virus (PepMoV), by recognizing the viral avirulence protein NIb. To figure out the Pvr4-mediated HR mechanism, we analyzed signaling component genes and structure-function relationships of Pvr4, using chimeras and deletion mutants in Nicotiana benthamiana. Molecular chaperone components including HSP90, SGT1, and RAR1 were required, while plant hormones and mitogen-activated protein kinase signaling components had little effect on Pvr4-NIb-mediated HR cell death. Domain swap analyses indicated that the LRR domain of Pvr4 determines recognition of PepMoV-NIb. Our deletion analysis further revealed that the CC domain or CC-NBARC domain alone can trigger autoactive cell death in N. benthamiana. However, the fragments having only an LRR domain could suppress CC-NBARC domain-induced cell death in trans. Further, C-terminal truncation analysis of Pvr4 revealed that a minimum three of five LRR exons showing high similarity was essential for Pvr4 function. The LRR domain may maintain Pvr4 in an inactive state in the absence of NIb. These results provide further insight into the structure and function of NLR protein signaling in plants.

scholarly journals Dissection of Cell Death Induction by Wheat Stem Rust Resistance Protein Sr35 and Its Matching Effector AvrSr35

2020 ◽  
Vol 33 (2) ◽  
pp. 308-319 ◽  
Author(s):  
Stephen Bolus ◽  
Eduard Akhunov ◽  
Gitta Coaker ◽  
Jorge Dubcovsky
Keyword(s):  
Cell Death ◽  
Transient Expression ◽  
Stem Rust ◽  
Fluorescent Protein ◽  
Coiled Coil ◽  
Nucleotide Binding ◽  
Leucine Rich Repeat ◽  
Wheat Stem Rust ◽  
Pathogen Effector ◽  
Lrr Domain

Nucleotide-binding leucine-rich repeat receptors (NLRs) are the most abundant type of immune receptors in plants and can trigger a rapid cell-death (hypersensitive) response upon sensing pathogens. We previously cloned the wheat NLR Sr35, which encodes a coiled-coil (CC) NLR that confers resistance to the virulent wheat stem rust race Ug99. Here, we investigated Sr35 signaling after Agrobacterium-mediated transient expression in Nicotiana benthamiana. Expression of Sr35 in N. benthamiana leaves triggered a mild cell-death response, which is enhanced in the autoactive mutant Sr35 D503V. The N-terminal tagging of Sr35 with green fluorescent protein (GFP) blocked the induction of cell death, whereas a C-terminal GFP tag did not. No domain truncations of Sr35 generated cell-death responses as strong as the wild type, but a truncation including the NB-ARC (nucleotide binding adaptor) shared by APAF-1, R proteins, and CED-4 domains in combination with the D503V autoactive mutation triggered cell death. In addition, coexpression of Sr35 with the matching pathogen effector protein AvrSr35 resulted in robust cell death and electrolyte leakage levels that were similar to autoactive Sr35 and significantly higher than Sr35 alone. Coexpression of Sr35-CC-NB-ARC and AvrSr35 did not induce cell death, confirming the importance of the leucine-rich repeat (LRR) domain for AvrSr35 recognition. These findings were confirmed through Agrobacterium-mediated transient expression in barley. Taken together, these results implicate the CC-NB-ARC domains of Sr35 in inducing cell death and the LRR domain in AvrSr35 recognition. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

scholarly journals TIR-only protein RBA1 recognizes a pathogen effector to regulate cell death inArabidopsis

2017 ◽  
Vol 114 (10) ◽  
pp. E2053-E2062 ◽  
Author(s):  
Marc T. Nishimura ◽  
Ryan G. Anderson ◽  
Karen A. Cherkis ◽  
Terry F. Law ◽  
Qingli L. Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune System ◽  
Pasteurella Multocida ◽  
Coiled Coil ◽  
Nucleotide Binding ◽  
Leucine Rich Repeat ◽  
Multidomain Structure ◽  
Pathogen Effector ◽  
Self Association ◽  
And Function

Detection of pathogens by plants is mediated by intracellular nucleotide-binding site leucine-rich repeat (NLR) receptor proteins. NLR proteins are defined by their stereotypical multidomain structure: an N-terminal Toll–interleukin receptor (TIR) or coiled-coil (CC) domain, a central nucleotide-binding (NB) domain, and a C-terminal leucine-rich repeat (LRR). The plant innate immune system contains a limited NLR repertoire that functions to recognize all potential pathogens. We isolated Response to the bacterial type III effector protein HopBA1 (RBA1), a gene that encodes a TIR-only protein lacking all other canonical NLR domains. RBA1 is sufficient to trigger cell death in response to HopBA1. We generated a crystal structure for HopBA1 and found that it has similarity to a class of proteins that includes esterases, the heme-binding protein ChaN, and an uncharacterized domain ofPasteurella multocidatoxin. Self-association, coimmunoprecipitation with HopBA1, and function of RBA1 require two previously identified TIR–TIR dimerization interfaces. Although previously described as distinct in other TIR proteins, in RBA1 neither of these interfaces is sufficient when the other is disrupted. These data suggest that oligomerization of RBA1 is required for function. Our identification of RBA1 demonstrates that “truncated” NLRs can function as pathogen sensors, expanding our understanding of both receptor architecture and the mechanism of activation in the plant immune system.

scholarly journals Mitogen-activated Protein Kinase Kinase Antagonized Fas-associated Death Domain Protein–mediated Apoptosis by Induced FLICE-inhibitory Protein Expression

1998 ◽  
Vol 188 (10) ◽  
pp. 1795-1802 ◽  
Author(s):  
Jung-Hua Yeh ◽  
Shu-Ching Hsu ◽  
Shou-Hwa Han ◽  
Ming-Zong Lai
Keyword(s):  
Cell Death ◽  
Map Kinase ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
General Mechanism ◽  
Death Domain ◽  
Con A ◽  
Inhibitory Protein ◽  
Mitogen Activated Protein

Fas and Fas-associated death domain (FADD) play a critical role in the homeostasis of different cell types. The regulation of Fas and FADD-mediated cell death is pivotal to many physiological functions. The activation of T lymphocytes by concanavalin A (Con A) inhibited Fas-mediated cell death. We identified that among the several activation signals downstream of Con A stimulation, mitogen-activated protein (MAP) kinase kinase (MKK) was the major kinase pathway that antagonized Fas-triggered cell death. MKK1 suppressed FADD- but not caspase-3– induced apoptosis, indicating that antagonism occurred early along the Fas-initiated apoptotic cascade. We further demonstrated that activation of MKK1 led to expression of FLIP, a specific inhibitor of FADD. MKK1 inhibition of FADD-induced cell death was abrogated if induction of FLIP was prevented, indicating that FLIP mediates MKK1 suppression of FADD-mediated apoptosis. Our results illustrate a general mechanism by which activation of MAP kinase attenuates apoptotic signals initiated by death receptors in normal and transformed cells.

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.

Amentoflavone Inhibits Osteoclastogenesis and Wear Debris-Induced Osteolysis via Suppressing NF-κB and MAPKs Signaling Pathways

Planta Medica ◽  
2018 ◽  
Vol 84 (11) ◽  
pp. 759-767 ◽  
Author(s):  
Zhen Zhang ◽  
Shuai Zhao ◽  
Xiaolei Li ◽  
Xiaoqi Zhuo ◽  
Wu Zhang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Aseptic Loosening ◽  
Wear Debris ◽  
Mitogen Activated Protein Kinase ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Mitogen Activated Protein ◽  
And Function

AbstractWear debris-induced osteolysis is one of the major reasons for subsequent aseptic loosening after cementless hip arthroplasty. Increasing evidence suggests that receptor activator of nuclear factor kappa-B (NF-κB) ligand-mediated osteoclastogenesis and osteolysis are responsible for wear debris-induced aseptic loosening. In the present study, we explored the effect of amentoflavone (AMF) on inhibiting osteoclast generation and wear debris-induced osteolysis in vitro and in vivo. Twenty-four male C57BL/J6 mice were randomly divided into four groups: a sham group and groups with titanium wear debris treatment followed by intraperitoneal injection of various concentrations of AMF (0, 20, and 40 mg/kg/day). The micro computed tomography scanning and histological analysis were performed. Bone marrow-derived macrophages were cultured to investigate the effect of AMF on osteoclast generation and function. The results showed that AMF suppressed osteoclastogenesis, F-actin ring formation, and bone absorption without cytotoxicity. AMF prevented titanium wear debris-induced osteolysis in mice. AMF suppressed the relative proteins of NF-κB and mitogen-activated protein kinase (MAPKs) signaling pathways. Thus, the present study suggests that AMF derived from plants could inhibit osteoclastogenesis and titanium wear debris-induced osteolysis via suppressing NF-κB and MAPKs signaling pathways.

scholarly journals Pro-apoptotic and pro-proliferation functions of the JNK pathway of Drosophila : roles in cell competition, tumorigenesis and regeneration

Open Biology ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 180256 ◽  
Author(s):  
Noelia Pinal ◽  
Manuel Calleja ◽  
Ginés Morata
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Animal Species ◽  
Mitogen Activated Protein Kinase ◽  
Intrinsic Properties ◽  
Cell Competition ◽  
Apparent Paradox ◽  
Jnk Pathway ◽  
Mitogen Activated Protein ◽  
Cellular Context

The Jun N-terminal kinase (JNK) is a member of the mitogen-activated protein kinase family. It appears to be conserved in all animal species where it regulates important physiological functions involved in apoptosis, cell migration, cell proliferation and regeneration. In this review, we focus on the functions of JNK in Drosophila imaginal discs, where it has been reported that it can induce both cell death and cell proliferation. We discuss this apparent paradox in the light of recent findings and propose that the pro-apoptotic and the pro-proliferative functions are intrinsic properties of JNK activity. Whether one function or another is predominant depends on the cellular context.

scholarly journals 1-O-Hexyl-2,3,5-Trimethylhydroquinone Ameliorates l-DOPA-Induced Cytotoxicity in PC12 Cells

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 867 ◽  
Author(s):  
Hyun Park ◽  
Jong Kang ◽  
Myung Lee
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Pc12 Cells ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Mitogen Activated Protein Kinase ◽  
Protective Effects ◽  
Extracellular Signal ◽  
Dopaminergic Neuronal Cell ◽  
Mitogen Activated Protein

1-O-Hexyl-2,3,5-trimethylhydroquinone (HTHQ) has previously been found to have effective anti-oxidant and anti-lipid-peroxidative activity. We aimed to elucidate whether HTHQ can prevent dopaminergic neuronal cell death by investigating the effect on l-DOPA-induced cytotoxicity in PC12 cells. HTHQ protected from both l-DOPA-induced cell death and superoxide dismutase activity reduction. When assessing the effect of HTHQ on oxidative stress-related signaling pathways, HTHQ inhibited l-DOPA-induced phosphorylation of sustained extracellular signal-regulated kinases (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK1/2). HTHQ also normalized l-DOPA-reduced Bcl-2-associated death protein (Bad) phosphorylation and Bcl-2-associated X protein (Bax) expression, promoting cell survival. Taken together, HTHQ exhibits protective effects against l-DOPA-induced cell death through modulation of the ERK1/2-p38MAPK-JNK1/2-Bad-Bax signaling pathway in PC12 cells. These results suggest that HTHQ may show ameliorative effects against oxidative stress-induced dopaminergic neuronal cell death, although further studies in animal models of Parkinson’s disease are required to confirm this.

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