Disruption of the MAMP-Induced MEKK1-MKK1/MKK2-MPK4 Pathway Activates the TNL Immune Receptor SMN1/RPS6

Takagi, Momoko; Hamano, Kohei; Takagi, Hiroki; Morimoto, Takayuki; Akimitsu, Kazuya; Terauchi, Ryohei; Shirasu, Ken; Ichimura, Kazuya

doi:10.1093/pcp/pcy243

Cited by 44 publications

(34 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have previously reported that loss of function of SMN1/RPS6, encoding a TNL immune receptor, partially suppressed the dwarf, autoimmune phenotypes of the mekk1 and mpk4 mutants, and suggested that SMN1/RPS6 monitors the integrity of the MEKK1-MKK1/MKK2-MPK4 pathway (Takagi et al, 2019). In this study, we found that SMN2 is identical to HEN2 and is the causal gene of the second complementation group of the smn mutants.…”

Section: Discussionsupporting

confidence: 52%

“…mutations SMN1 is involved in the dwarf, autoimmune phenotype of mpk4 (Takagi et al, 2019). To examine whether the smn2 and hen2 mutations suppress the mpk4 phenotypes, we produced mpk4smn2-85 and mpk4hen2-1 double mutants.…”

Section: Suppression Of Dwarf Autoimmune Phenotypes Of Mpk4 By Smn2 and Hen2mentioning

confidence: 99%

“…SUMM3/CRCK3 and PAT1 may serve as a guardee or decoy of SUMM2 (Zhang et al, 2017). protein RPS6, which recognizes the HopA1 effector from Pseudomonas syringae and is required for resistance to this pathogen (Kim et al, 2009;Takagi et al, 2019). Mutations in SMN1/RPS6 partially suppress the dwarf, autoimmune phenotypes of mekk1 and mpk4.…”

Section: Introductionmentioning

confidence: 99%

“…We have suggested that two structurally distinct NLR proteins, SMN1/RPS6 and SUMM2, monitor the integrity of the MEKK1-MKK1/MKK2-MPK4 pathway (Takagi et al, 2019). The mRNA levels of SMN1/RPS6 are regulated by the nonsense-mediated mRNA decay (NMD) surveillance mechanism that degrades aberrant mRNAs in the processing body (P-body) in the cytosol (Gloggnitzer et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Arabidopsis SMN2/HEN2, Encoding DEAD-Box RNA Helicase, Governs Proper Expression of the Resistance Gene SMN1/RPS6 and Is Involved in Dwarf, Autoimmune Phenotypes of mekk1 and mpk4 Mutants

Takagi

Iwamoto

Kubo

et al. 2020

Plant and Cell Physiology

Self Cite

View full text Add to dashboard Cite

In Arabidopsis thaliana, a mitogen-activated protein kinase pathway, MEKK1–MKK1/MKK2–MPK4, is important for basal resistance and disruption of this pathway results in dwarf, autoimmune phenotypes. To elucidate the complex mechanisms activated by the disruption of this pathway, we have previously developed a mutant screening system based on a dwarf autoimmune line that overexpressed the N-terminal regulatory domain of MEKK1. Here, we report that the second group of mutants, smn2, had defects in the SMN2 gene, encoding a DEAD-box RNA helicase. SMN2 is identical to HEN2, whose function is vital for the nuclear RNA exosome because it provides non-ribosomal RNA specificity for RNA turnover, RNA quality control and RNA processing. Aberrant SMN1/RPS6 transcripts were detected in smn2 and hen2 mutants. Disease resistance against Pseudomonas syringae pv. tomato DC3000 (hopA1), which is conferred by SMN1/RPS6, was decreased in smn2 mutants, suggesting a functional connection between SMN1/RPS6 and SMN2/HEN2. We produced double mutants mekk1smn2 and mpk4smn2 to determine whether the smn2 mutations suppress the dwarf, autoimmune phenotypes of the mekk1 and mpk4 mutants, as the smn1 mutations do. As expected, the mekk1 and mpk4 phenotypes were suppressed by the smn2 mutations. These results suggested that SMN2 is involved in the proper function of SMN1/RPS6. The Gene Ontology enrichment analysis using RNA-seq data showed that defense genes were downregulated in smn2, suggesting a positive contribution of SMN2 to the genome-wide expression of defense genes. In conclusion, this study provides novel insight into plant immunity via SMN2/HEN2, an essential component of the nuclear RNA exosome.

show abstract

Section: Discussionsupporting

confidence: 52%

Section: Suppression Of Dwarf Autoimmune Phenotypes Of Mpk4 By Smn2 and Hen2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Arabidopsis SMN2/HEN2, Encoding DEAD-Box RNA Helicase, Governs Proper Expression of the Resistance Gene SMN1/RPS6 and Is Involved in Dwarf, Autoimmune Phenotypes of mekk1 and mpk4 Mutants

Takagi

Iwamoto

Kubo

et al. 2020

Plant and Cell Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The complexity of the MPK4 pathway is also shown by the recent identification of RPS6 as yet another NLR that guards the MEKK1-MKK1/2-MPK4 pathway by specifically surveilling the presence of the HopA1 effector protein of the bacterial pathogen Pseudomonas syringae pv. tomato [47].…”

Section: Mpk4 Is a Regulator Of Alternative Splicing In Pamp-triggerementioning

confidence: 99%

Role of MPK4 in pathogen-associated molecular pattern-triggered alternative splicing in Arabidopsis

et al. 2020

View full text Add to dashboard Cite

Alternative splicing (AS) of pre-mRNAs in plants is an important mechanism of gene regulation in environmental stress tolerance but plant signals involved are essentially unknown. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is mediated by mitogen-activated protein kinases and the majority of PTI defense genes are regulated by MPK3, MPK4 and MPK6. These responses have been mainly analyzed at the transcriptional level, however many splicing factors are direct targets of MAPKs. Here, we studied alternative splicing induced by the PAMP flagellin in Arabidopsis. We identified 506 PAMPinduced differentially alternatively spliced (DAS) genes. Importantly, of the 506 PAMPinduced DAS genes, only 89 overlap with the set of 1950 PAMP-induced differentially expressed genes (DEG), indicating that transcriptome analysis does not identify most DAS events. Global DAS analysis of mpk3, mpk4, and mpk6 mutants in the absence of PAMP treatment showed no major splicing changes. However, in contrast to MPK3 and MPK6, MPK4 was found to be a key regulator of PAMP-induced DAS events as the AS of a number of splicing factors and immunity-related protein kinases is affected, such as the calciumdependent protein kinase CPK28, the cysteine-rich receptor like kinases CRK13 and CRK29 or the FLS2 co-receptor SERK4/BKK1. Although MPK4 is guarded by SUMM2 and consequently, the mpk4 dwarf and DEG phenotypes are suppressed in mpk4 summ2 mutants, MPK4-dependent DAS is not suppressed by SUMM2, supporting the notion that PAMP-triggered MPK4 activation mediates regulation of alternative splicing.

show abstract

Specificity models in MAPK cascade signaling

Nicolet

2023

FEBS Open Bio

View full text Add to dashboard Cite

The precise execution of various cellular functions relies on the maintenance of signaling specificity from input detection to cellular outputs. However, diverse signaling pathways share similar or identical intermediate components. A well‐conserved intermediate, the Mitogen‐Activated Protein Kinase (MAPK) cascade, participates in a myriad of signaling pathways, regulating signal transduction from input to output. This typifies the “hourglass conundrum”, where a multitude of inputs and outputs all operate through a limited number of common intermediates. Therefore, understanding how MAPK cascades regulate a variety of outputs with specificity is a fundamental question in biology. This review highlights four major insulating mechanisms that improve signaling specificity: selective activation, compartmentalization, combinatorial signaling, and cross‐pathway inhibition. We focus on plant pathways that share MAPK cascade components and compare mechanisms with those of animals and yeast. We hope this conceptual overview will aid future studies to better understand plant signaling specificity.

show abstract

Disruption of the MAMP-Induced MEKK1-MKK1/MKK2-MPK4 Pathway Activates the TNL Immune Receptor SMN1/RPS6

Cited by 44 publications

References 43 publications

Arabidopsis SMN2/HEN2, Encoding DEAD-Box RNA Helicase, Governs Proper Expression of the Resistance Gene SMN1/RPS6 and Is Involved in Dwarf, Autoimmune Phenotypes of mekk1 and mpk4 Mutants

Arabidopsis SMN2/HEN2, Encoding DEAD-Box RNA Helicase, Governs Proper Expression of the Resistance Gene SMN1/RPS6 and Is Involved in Dwarf, Autoimmune Phenotypes of mekk1 and mpk4 Mutants

Role of MPK4 in pathogen-associated molecular pattern-triggered alternative splicing in Arabidopsis

Specificity models in MAPK cascade signaling

Contact Info

Product

Resources

About