scholarly journals role of FLS3 and BSK830 in pattern-triggered immunity in tomato

2016 ◽  
Author(s):  
Guido Sessa ◽  
Gregory Martin
Keyword(s):  
Cell Death ◽  
Plant Cell ◽  
Kinase Activity ◽  
Mapk Signaling ◽  
Negative Regulator ◽  
Cell Periphery ◽  
Specific Class ◽  
Induced Responses ◽  
Research Activities

Pattern-recognition receptors (PRRs) located on the plant cell surface initiate immune responses by perceiving conserved pathogen molecules known as pathogen-associated molecular patterns (PAMPs). PRRs typically function in multiprotein complexes that include transmembrane and cytoplasmickinases and contribute to the initiation and signaling of pattern-triggered immunity (PTI). An important challenge is to identify molecular components of PRR complexes and downstream signaling pathways, and to understand the molecular mechanisms that mediate their function. In research activities supported by BARD-4931, we studied the role of the FLAGELLIN SENSING 3 (FLS3) PRR in the response of tomato leaves to flagellin-derivedPAMPs and PTI. In addition, we investigated molecular properties of the tomato brassinosteroid signaling kinase 830 (BSK830) that physically interacts with FLS3 and is a candidate for acting in the FLS3 signaling pathway. Our investigation refers to the proposal original objectives that were to: 1) Investigate the role of FLS3 and its interacting proteins in PTI; 2) Investigate the role of BSK830 in PTI; 3) Examine molecular and phosphorylation dynamics of the FLS3-BSK830 interaction; 4) Examine the possible interaction of FLS3 and BSK830 with Pstand Xcveffectors. We used CRISPR/Cas9 techniques to develop plants carrying single or combined mutations in the FLS3 gene and in the paralogsFLS2.1 and FLS2.2 genes, which encode the receptor FLAGELLIN SENSING2 (FLS2), and analyzed their function in PTI. Domain swapping analysis of the FLS2 and FLS3 receptors revealed domains of the proteins responsible for PAMP detection and for the different ROS response initiated by flgII-28/FLS3 as compared to flg22/FLS2. In addition, in vitro kinase assays and point mutations analysis identified FLS2 and FLS3 domains required for kinase activity and ATP binding. In research activities on tomato BSK830, we found that it interacts with PRRs and with the co-receptor SERK3A and PAMP treatment affects part of these interactions. CRISPR/Cas9 bsk830 mutant plants displayed enhanced pathogen susceptibility and reduced ROS production upon PAMP treatment. In addition, BSK830 interacted with 8 Xanthomonastype III secreted effectors. Follow up analysis revealed that among these effectors XopAE is part of an operon, is translocated into plant cells, and displays E3 ubiquitinligase activity. Our investigation was also extended to other Arabidopsis and tomato BSK family members. Arabidopsis BSK5 localized to the plant cell periphery, interacted with receptor-like kinases, and it was phosphorylatedin vitro by the PEPR1 and EFRPRRs. bsk5 mutant plants displayed enhanced susceptibility to pathogens and were impaired in several, but not all, PAMP-induced responses. Conversely, BSK5 overexpression conferred enhanced disease resistance and caused stronger PTI responses. Genetic complementation suggested that proper localization, kinase activity, and phosphorylation by PRRs are critical for BSK5 function. BSK7 and BSK8 specifically interacted with the FLS2 PRR, their respective mutant plants were more susceptible to B. cinereaand displayed reduced flg22-induced responses. The tomato BSK Mai1 was found to interact with the M3KMAPKKK, which is involved in activation of cell death associated with effector-triggered immunity. Silencing of Mai1 in N. benthamianaplants compromised cell death induced by a specific class of immune receptors. In addition, co-expression of Mai1 and M3Kin leaves enhanced MAPKphosphorylation and cell death, suggesting that Mai1 acts as a molecular link between pathogen recognition and MAPK signaling. Finally, We identified the PP2C phosphatase Pic1 that acts as a negative regulator of PTI by interacting with and dephosphorylating the receptor-like cytoplasmickinase Pti1, which is a positive regulator of plant immunity. The results of this investigation shed new light on the molecular characteristics and interactions of components of the immune system of crop plants providing new knowledge and tools for development of novel strategies for disease control. 

scholarly journals Death-domain dimerization-mediated activation of RIPK1 controls necroptosis and RIPK1-dependent apoptosis

2018 ◽  
Vol 115 (9) ◽  
pp. E2001-E2009 ◽  
Author(s):  
Huyan Meng ◽  
Zhen Liu ◽  
Xingyan Li ◽  
Huibing Wang ◽  
Taijie Jin ◽  
...  
Keyword(s):  
Cell Death ◽  
Proinflammatory Cytokine ◽  
Kinase Activity ◽  
Kinase Domain ◽  
Death Domain ◽  
Degenerative Diseases ◽  
Intermediate Domain ◽  
A Charge ◽  
Mutant Cells

RIPK1 is a critical mediator of cell death and inflammation downstream of TNFR1 upon stimulation by TNFα, a potent proinflammatory cytokine involved in a multitude of human inflammatory and degenerative diseases. RIPK1 contains an N-terminal kinase domain, an intermediate domain, and a C-terminal death domain (DD). The kinase activity of RIPK1 promotes cell death and inflammation. Here, we investigated the involvement of RIPK1-DD in the regulation of RIPK1 kinase activity. We show that a charge-conserved mutation of a lysine located on the surface of DD (K599R in human RIPK1 or K584R in murine RIPK1) blocks RIPK1 activation in necroptosis and RIPK1-dependent apoptosis and the formation of complex II. Ripk1K584R/K584R knockin mutant cells are resistant to RIPK1 kinase-dependent apoptosis and necroptosis. The resistance of K584R cells, however, can be overcome by forced dimerization of RIPK1. Finally, we show that the K584R RIPK1 knockin mutation protects mice against TNFα-induced systematic inflammatory response syndrome. Our study demonstrates the role of RIPK1-DD in mediating RIPK1 dimerization and activation of its kinase activity during necroptosis and RIPK1-dependent apoptosis.

Role of oxidative stress and MAPK signaling in reference moist smokeless tobacco-induced HOK-16B cell death

2010 ◽  
Vol 195 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Clint Mitchell ◽  
Andrew R. Joyce ◽  
John T. Piper ◽  
Robert J. McKallip ◽  
Marc W. Fariss
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Smokeless Tobacco ◽  
Mapk Signaling

scholarly journals The role of vacuole in plant cell death

2011 ◽  
Vol 18 (8) ◽  
pp. 1298-1304 ◽  
Author(s):  
I Hara-Nishimura ◽  
N Hatsugai
Keyword(s):  
Cell Death ◽  
Plant Cell

TaMDAR6acts as a negative regulator of plant cell death and participates indirectly in stomatal regulation during the wheat stripe rust-fungus interaction

2015 ◽  
Vol 156 (3) ◽  
pp. 262-277 ◽  
Author(s):  
Mohamed Awaad Abou-Attia ◽  
Xiaojie Wang ◽  
Mohamed Nashaat Al-Attala ◽  
Qiang Xu ◽  
Gangming Zhan ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Cell ◽  
Stripe Rust ◽  
Rust Fungus ◽  
Negative Regulator ◽  
Wheat Stripe Rust ◽  
Stomatal Regulation ◽  
Stripe Rust Fungus

scholarly journals Human tumor genomics and zebrafish modeling identifySPRED1loss as a driver of mucosal melanoma

Science ◽  
2018 ◽  
Vol 362 (6418) ◽  
pp. 1055-1060 ◽  
Author(s):  
Julien Ablain ◽  
Mengshu Xu ◽  
Harriet Rothschild ◽  
Richard C. Jordan ◽  
Jeffrey K. Mito ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Point Mutations ◽  
Human Tumor ◽  
Mapk Signaling ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Driver Genes ◽  
Mucosal Surfaces ◽  
Mutation Burden ◽  
Mitogen Activated Protein

Melanomas originating from mucosal surfaces have low mutation burden, genomic instability, and poor prognosis. To identify potential driver genes, we sequenced hundreds of cancer-related genes in 43 human mucosal melanomas, cataloging point mutations, amplifications, and deletions. TheSPRED1gene, which encodes a negative regulator of mitogen-activated protein kinase (MAPK) signaling, was inactivated in 37% of the tumors. Four distinct genotypes were associated withSPRED1loss. Using a rapid, tissue-specific CRISPR technique to model these genotypes in zebrafish, we found thatSPRED1functions as a tumor suppressor, particularly in the context ofKITmutations.SPRED1knockdown caused MAPK activation, increased cell proliferation, and conferred resistance to drugs inhibiting KIT tyrosine kinase activity. These findings provide a rationale for MAPK inhibition in SPRED1-deficient melanomas and introduce a zebrafish modeling approach that can be used more generally to dissect genetic interactions in cancer.

scholarly journals RIPK1-dependent apoptosis bypasses pathogen blockade of innate signaling to promote immune defense

2017 ◽  
Vol 214 (11) ◽  
pp. 3171-3182 ◽  
Author(s):  
Lance W. Peterson ◽  
Naomi H. Philip ◽  
Alexandra DeLaney ◽  
Meghan A. Wynosky-Dolfi ◽  
Kendra Asklof ◽  
...  
Keyword(s):  
Cell Death ◽  
Kinase Activity ◽  
Cytokine Production ◽  
Mapk Signaling ◽  
Immune Defense ◽  
Effector Proteins ◽  
Host Cells ◽  
Effector Triggered Immunity ◽  
Induced Apoptosis

Many pathogens deliver virulence factors or effectors into host cells in order to evade host defenses and establish infection. Although such effector proteins disrupt critical cellular signaling pathways, they also trigger specific antipathogen responses, a process termed “effector-triggered immunity.” The Gram-negative bacterial pathogen Yersinia inactivates critical proteins of the NF-κB and MAPK signaling cascade, thereby blocking inflammatory cytokine production but also inducing apoptosis. Yersinia-induced apoptosis requires the kinase activity of receptor-interacting protein kinase 1 (RIPK1), a key regulator of cell death, NF-κB, and MAPK signaling. Through the targeted disruption of RIPK1 kinase activity, which selectively disrupts RIPK1-dependent cell death, we now reveal that Yersinia-induced apoptosis is critical for host survival, containment of bacteria in granulomas, and control of bacterial burdens in vivo. We demonstrate that this apoptotic response provides a cell-extrinsic signal that promotes optimal innate immune cytokine production and antibacterial defense, demonstrating a novel role for RIPK1 kinase–induced apoptosis in mediating effector-triggered immunity to circumvent pathogen inhibition of immune signaling.

scholarly journals Spotted leaf11, a Negative Regulator of Plant Cell Death and Defense, Encodes a U-Box/Armadillo Repeat Protein Endowed with E3 Ubiquitin Ligase Activity

2004 ◽  
Vol 16 (10) ◽  
pp. 2795-2808 ◽  
Author(s):  
Li-Rong Zeng ◽  
Shaohong Qu ◽  
Alicia Bordeos ◽  
Chengwei Yang ◽  
Marietta Baraoidan ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Cell ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Negative Regulator ◽  
Repeat Protein ◽  
Ubiquitin Ligase Activity ◽  
Armadillo Repeat

scholarly journals Root-derived trans-zeatin cytokinin protects Arabidopsis plants against photoperiod stress

2020 ◽  
Author(s):  
Manuel Frank ◽  
Anne Cortleven ◽  
Ondrej Novak ◽  
Thomas Schmülling
Keyword(s):  
Cell Death ◽  
Response Regulator ◽  
Light Period ◽  
Negative Regulator ◽  
Marker Genes ◽  
Signaling Proteins ◽  
Negative Consequences ◽  
Regulatory Circuit ◽  
Cytokinin Synthesis

ABSTRACTRecently, a novel type of abiotic stress caused by a prolongation of the light period - coined photoperiod stress - has been described in Arabidopsis. During the night after the prolongation of the light period, stress and cell death marker genes are induced. The next day, strongly stressed plants display a reduced photosynthetic efficiency and leaf cells eventually enter programmed cell death. The phytohormone cytokinin (CK) acts as a negative regulator of this photoperiod stress syndrome. In this study, we show that Arabidopsis wild-type plants increase the CK concentration in response to photoperiod stress. Analysis of cytokinin synthesis and transport mutants revealed that root-derived trans-zeatin (tZ)-type CKs protect against photoperiod stress. The CK signaling proteins ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 2 (AHP2), AHP3 and AHP5 and transcription factors ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), ARR10 and ARR12 are required for the protective activity of CK. Analysis of higher order B-type arr mutants suggested that a complex regulatory circuit exists in which the loss of ARR10 or ARR12 can rescue the arr2 phenotype. Together the results revealed the role of root-derived CK acting in the shoot through the two-component signaling system to protect from the negative consequences of strong photoperiod stress.

scholarly journals Stim1 Deletion Synthetically Rescues Ezh2-Null Effector T Cells and Alloimmunity

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4533-4533
Author(s):  
Ying Wang ◽  
Shan He ◽  
Yongnian Liu ◽  
Robert Hooper ◽  
Hongshuang Yu ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Effector T Cells ◽  
Conditional Knockout ◽  
Negative Regulator ◽  
Sequencing Analysis ◽  
Major Barrier ◽  
Donor T Cells

Abstract Graft-versus-host disease (GVHD) remains a major barrier for the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT). We have identified the central role of the histone methyltransferase Ezh2 in regulating allogeneic T-cell expansion, differentiation and function. Conditional loss of Ezh2 in donor T cells inhibits GVHD in mice due to the inability of alloreactive T cells to persist. However, the molecular mechanism by which Ezh2 deficiency causes alloreactive T cell death remains unknown. Here we demonstrate that genetic deletion of Stromal Interaction Molecule (Stim) 1, a dynamic endoplasmic reticulum Ca2+ sensor and regulator of Ca2+ signaling, rescues antigen-activated Ezh2-null (Ezh2-/-) T cells, leading to restored persistence of alloreactive effector T cells in mice and severe GVHD. Using RNA-sequencing analysis, we found Ezh2-deficiency led to the upregulation of multiple genes (e.g., Ifng, Prf1, Ccl5, Ccl4, Upp1 and Spp1) known to be regulated by Ca2+ signals through calcineurin (CN), the primary target of the immunosuppressant cyclosporine A (CsA). This reverse correlation between Ezh2 inhibition and CsA-treatment for gene expression suggests that Ezh2 may antagonize Ca2+ signaling in activated T cells. Calcium signaling assays revealed higher cytosolic Ca2+ uptake and more frequent Ca2+ oscillations in Ezh2-/- T cells. Moreover, Ezh2-/- T cells exhibited significantly increased polarization of Stim1 and Orai1 in the cellular membrane. These data reveal an unexpected role of Ezh2 as a negative regulator of Ca2+ entry, thereby serving as a 'brake' for Ca2+ signaling. Using the C57BL/6 (B6) into Balb/c mouse GVHD model, we found significantly fewer Ezh2-/- or Stim1-/- IFN-g-secreting effector T cells compared to the WT counterparts on day 8 or 14 post-transplantation. In contrast, deleting Stim1 from Ezh2-/- donor T cells rescued the cells in the spleen and liver, producing even more donor T cells and IFN-g-secreting effector T cells compared to WT T cells and inducing severe GVHD. We further examined the cell autonomous effect of Stim1 deletion on the rescue of Ezh2-/- T cells by mixing WT T cells (B6/SJL, CD45.1) with Ezh2- and/or Stim1- conditional knockout T cells (i.e., Ezh2-/-, Stim1-/- or Ezh2-/- x Stim1-/- B6 T cells (CD45.2)) at a ratio of 1:1 before transferring into the Balb/c mice. While loss of either Ezh2 or Stim1 led to lower frequency of IFN-g+IL-2+ effector T cells, combined deletion of both genes restored the frequency and number of IFN-g+IL-2+ effector T cells to that of WT T cells. Thus, Stim1-mediated Ca2+ signals are crucial for mediating cell death in alloantigen-driven Ezh2-/- effector T cells. To further determine whether the inhibition of CN-NFAT contributes to the rescue, we treated T cell receptor (TCR)-activated Ezh2-/- T cells with CsA or the calcium release-activated channel specific inhibitor BTP2, respectively, in vitro. While BTP2 dramatically improved the survival of IFN-g-producing effector T cells, CsA did not, suggesting the involvement of CN-NFAT-independent pathways. Ca2+ overload is known to impair mitochondrial function and cause massive cell death. As compared to TCR-activated WT T cells, activated Ezh2-/- T cells displayed significantly less ATP, lower mitochondrial membrane potential, enlarged mitochondrial mass, and decreased capacity to upregulate oxidative phosphorylation. Stim1 deletion largely reversed the metabolic defect in Ezh2-/- T cells, indicating the critical role of mitochondrial metabolism in rescuing these T cells. Considered together, our findings identify the remarkable coordination between Ezh2- and Stim1-regulated effector T cell persistence. As such, these investigations may lead to new approaches to inhibit GVHD, with broad implications to defining fundamental mechanisms of T cell differentiation for control of adaptive immunity, such as tumor immunity and autoimmunity. Disclosures Reshef: Incyte: Consultancy; Takeda Pharmaceuticals: Consultancy; Pfizer: Consultancy; Kite Pharma: Consultancy; Atara Biotherapeutics: Consultancy; Bristol-Myers Squibb: Consultancy.

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