G3BPs in Plant Stress

The sessile nature of plants enforces highly adaptable strategies to adapt to different environmental stresses. Plants respond to these stresses by a massive reprogramming of mRNA metabolism. Balancing of mRNA fates, including translation, sequestration, and decay is essential for plants to not only coordinate growth and development but also to combat biotic and abiotic environmental stresses. RNA stress granules (SGs) and processing bodies (P bodies) synchronize mRNA metabolism for optimum functioning of an organism. SGs are evolutionarily conserved cytoplasmic localized RNA-protein storage sites that are formed in response to adverse conditions, harboring mostly but not always translationally inactive mRNAs. SGs disassemble and release mRNAs into a translationally active form upon stress relief. RasGAP SH3 domain binding proteins (G3BPs or Rasputins) are “scaffolds” for the assembly and stability of SGs, which coordinate receptor mediated signal transduction with RNA metabolism. The role of G3BPs in the formation of SGs is well established in mammals, but G3BPs in plants are poorly characterized. In this review, we discuss recent findings of the dynamics and functions of plant G3BPs in response to environmental stresses and speculate on possible mechanisms such as transcription and post-translational modifications that might regulate the function of this important family of proteins

Insights into understanding the maturation of c-type cytochromes in plant mitochondria

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Phosphorylation regulates the activity of indeterminate-domain (IDD/BIRD) proteins in response to diverse environmental conditions

INDETERMINATE-DOMAIN proteins (IDDs) belong to a diverse plant-specific family of transcriptional regulators that coordinate distinct functions during plant growth and development. The functions of several of these IDD members are transcriptionally regulated, but so far nothing is known about the regulation at the post-translational level in spite of the fact that post-translational modifications of these proteins have been reported in several large-scale proteomics studies. Recently, we showed that IDD4 is a repressor of basal immunity and its characteristic traits are predominantly determined by the phosphorylation at two distinct phosphorylation sites. This finding prompted us to comprehensively review phosphorylation of the various IDD members from the plethora of phosphoproteomics studies demonstrating the post-translational modification of IDDs at highly conserved sites under various experimental conditions. We reckon that the phosphorylation of IDDs is an underrated mechanistic aspect in their regulation and we postulate their importance in IDD/BIRD functioning

Phosphorylation-dependent regulation of plant chromatin and chromatin-associated proteins

International audienceIn eukaryotes, most of the DNA is located in the nucleus where it is organized with histone proteins in a higher order structure as chromatin. Chromatin and chromatin‐associated proteins contribute to DNA‐related processes such as replication and transcription as well as epigenetic regulation. Protein functions are often regulated by PTMs among which phosphorylation is one of the most abundant PTM. Phosphorylation of proteins affects important properties, such as enzyme activity, protein stability, or subcellular localization. We here describe the main specificities of protein phosphorylation in plants and review the current knowledge on phosphorylation‐dependent regulation of plant chromatin and chromatin‐associated proteins. We also outline some future challenges to further elucidate protein phosphorylation and chromatin regulation

Plant immunity: The mti-emodel and beyond

In plant-microbe interactions, a pathogenic microbe initially has to overcome preformed and subsequently induced plant defenses. One of the initial host-induced defense responses is microbe-associated molecular pattern (MAMP)-triggered immunity (MTI). Successful pathogens attenuate MTI by delivering various effectors that result in effector-triggered susceptibility and disease. However, some host plants developed mechanisms to detect effectors and can trigger effector-triggered immunity (ETI), thereby abrogating pathogen infection and propagation. Despite the wide acceptance of the above concepts, more and more accumulating evidence suggests that the distinction between MAMPs and effectors and MTI and ETI is often not given. This review discusses the complexity of MTI and ETI signaling networks and elaborates the current state of the art of defining MAMPs versus effectors and MTI versus ETI, but also discusses new findings that challenge the current dichotomy of these concepts

Proteomic and phosphoproteomic analyses of chromatin-associated proteins from Arabidopsis thaliana

International audienceThe nucleus is the organelle where basically all DNA-related processes take place in eukaryotes, such as replication, transcription, and splicing as well as epigenetic regulation. The identification and description of the nuclear proteins is one of the requisites toward a comprehensive understanding of the biological functions accomplished in the nucleus. Many of the regulatory mechanisms of protein functions rely on their PTMs among which phosphorylation is probably one of the most important properties affecting enzymatic activity, interaction with other molecules, localization, or stability. So far, the nuclear and subnuclear proteome and phosphoproteome of the model plant Arabidopsis thaliana have been the subject of very few studies. In this work, we developed a purification protocol of Arabidopsis chromatin-associated proteins and performed proteomic and phosphoproteomic analyses identifying a total of 879 proteins of which 198 were phosphoproteins that were mainly involved in chromatin remodeling, transcriptional regulation, and RNA processing. From 230 precisely localized phosphorylation sites (phosphosites), 52 correspond to hitherto unidentified sites. This protocol and data thereby obtained should be a valuable resource for many domains of plant research

Plant immunity: The mti-emodel and beyond

In plant-microbe interactions, a pathogenic microbe initially has to overcome preformed and subsequently induced plant defenses. One of the initial host-induced defense responses is microbe-associated molecular pattern (MAMP)-triggered immunity (MTI). Successful pathogens attenuate MTI by delivering various effectors that result in effector-triggered susceptibility and disease. However, some host plants developed mechanisms to detect effectors and can trigger effector-triggered immunity (ETI), thereby abrogating pathogen infection and propagation. Despite the wide acceptance of the above concepts, more and more accumulating evidence suggests that the distinction between MAMPs and effectors and MTI and ETI is often not given. This review discusses the complexity of MTI and ETI signaling networks and elaborates the current state of the art of defining MAMPs versus effectors and MTI versus ETI, but also discusses new findings that challenge the current dichotomy of these concepts

Characterization of Protein-Protein Interactions: application to the understanding of peroxisome biogenesis.

International audienc