The mRNA decay factor PAT 1 functions in a pathway including MAP kinase 4 and immune receptor SUMM 2

Abstract

Multi-layered defense responses are activated in plants upon recognition of invading pathogens. Transmembrane receptors recognize conserved pathogen-associated molecular patterns (PAMPs) and activate MAP kinase cascades, which regulate changes in gene expression to produce appropriate immune responses. For example, Arabidopsis MAP kinase 4 (MPK4) regulates the expression of a subset of defense genes via at least one WRKY transcription factor. We report here that MPK4 is found in complexes in vivo with PAT1, a component of the mRNA decapping machinery. PAT1 is also phosphorylated by MPK4 and, upon flagellin PAMP treatment, PAT1 accumulates and localizes to cytoplasmic processing (P) bodies which are sites for mRNA decay. Pat1 mutants exhibit dwarfism and de-repressed immunity dependent on the immune receptor SUMM2. Since mRNA decapping is a critical step in mRNA turnover, linking MPK4 to mRNA decay via PAT1 provides another mechanism by which MPK4 may rapidly instigate immune responses.

Population genomics of the eastern cottonwood (Populus deltoides)

“…This X T X outlier also showed a very low Tajima's D value in the East‐K2 subpopulation and was identified by BAYENV2 as associated with mean temperature of the driest quarter. This gene encodes a putative topoisomerase II‐associated protein orthologous to PAT1 in Arabidopsis thaliana (AT1G79090), an mRNA decay factor involved in post‐transcriptional gene regulation and innate immune response to biotrophic and necrotrophic pathogens (Roux et al., 2015). In a genomewide association study, we recently conducted on the same P. deltoides population analyzed here (Fahrenkrog et al., 2017), a SNP present in this gene was positively associated with wood lignin content.…”

The LSM1-7 Complex Differentially Regulates Arabidopsis Tolerance to Abiotic Stress Conditions by Promoting Selective mRNA Decapping

“…How abiotic stresses regulate the cytoplasmic dynamics of proteins involved in RNA degradation and, ultimately, P-body formation is poorly understood. Phosphorylation of different components of human and Arabidopsis mRNA decapping machineries by mitogen-activated protein kinases (MPKs) during stress responses seems to be necessary for their cytoplasmic localization and for P-body assembly (Rzeczkowski et al, 2011;Roux et al, 2015). The sequence of LSM1 proteins (Perea-Resa et al, 2012) contains a consensus motif S/T-P for phosphorylation by MPK.…”

Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function

“…It is an MPK4 phosphorylation target that accumulates in PBs in response to the bacterial pathogen-associated molecular pattern flagellin22. PAT1 and MPK4 suppress plant autoimmunity, as loss of their function results in the ENHANCED DISEASE SUSCEPTIBILITY1-mediated constitutive immune response through a pathway downstream of the immune receptor SUPPRESSOR OF MKK1 MKK2 2 (Roux et al, 2015). Studies of the Arabidopsis LSM1-7-PAT1 complex extend the contribution of mRNA decapping from abiotic to biotic stress signaling and suggest that both components and architecture of the mRNA-decapping complex of yeast and metazoa are conserved in plants.…”

“…Immune response Roux et al (2015) ( affects the rhythmicity of the core clock oscillator mRNAs TIMING OF CAB EXPRESSION1 and CIR-CADIAN CLOCK ASSOCIATED1 (Delis et al, 2016). The second is the homodimeric DEDD-class PARNs found in plants and humans but apparently absent from budding yeast (Saccharomyces cerevisiae) and fruit flies (Drosophila melanogaster; Godwin et al, 2013).…”