Project description:How environmentally challenged plants can switch from growth to stress adaptation is an important question in plant physiology. To identify the key regulatory proteins and to characterize the underlying signaling pathways are essential in answering this question. Here we show that the abiotic stress hormone Abscisic acid (ABA) induces the expression of the Asparagine rich proteins (NRP), DCD1 and DCD2, to repress the auxin-induced growth by promoting vacuolar degradation of PIN2, the auxin efflux carrier. ABA-induced degradation of PIN2 is inhibited in the dcd1 dcd2 double mutant, and inhibition of FyPP3, the catalytic subunit of the PP6 protein phosphatase, can restore the PIN recycling and growth phenotype in the double mutant. Transcriptome analyses on WT, dcd1 dcd2, the FyPP3 Dominant Negative line (FyPP3-DN), and dcd1 dcd2/FyPP3-DN supported the essential function of the NRP-FyPP3 module in the growth- to stress-response switch.
Project description:Through releasing virulence molecules into host cells, intracellular bacteria interfere with host cellular functions and grow in the cells that engulf them. To ensure survival and virulence, these pathogens also manipulate host factors, but this process is not fully understood. In this study, we investigated the host molecular mechanisms required for intracellular bacterial growth in macrophages using Salmonella typhimurium (Salmonella) infection model and bacterial division reporter system. Upon Salmonella infection, Protein Phosphatase 6 (Pp6) was significantly reduced in macrophages containing growing bacteria. Conditional knockout of Pp6 increased host susceptibility to Salmonella-mediated killing, which was attributed to the poor resistance in Pp6-deficient macrophages. MicroRNA-31 (miR-31) was identified as a negative regulator of Pp6, and its conditional deletion promoted Salmonella clearance. Moreover, a yeast two-hybrid screening identified 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 (Pfkfb1), a key metabolic regulator, as a substrate of Pp6. Pp6-deficient macrophages exhibited elevated Pfkfb1 expression. Furthermore, we found that macrophages containing growing Salmonella exclusively exhibited high Pfkfb1 expression. Pfkfb1 deletion reduced bacterial growth, likely due to increased NO levels, while also downregulating arginase-1 (Arg-1) expression and impairing arginine biosynthesis and metabolism in macrophages. Together, we investigated the role of Pp6-Pfkfb1 axis in orchestrating host metabolic adaptions and intracellular bacterial survival, which may provide therapeutic targets for infectious diseases against intracellular multidrug-resistant bacteria.
Project description:Light-induced phosphorylation is necessary and essential for the degradation of phytochrome-interacting factors (PIFs), the central repressors of photomorphogenesis. Although the kinases responsible for PIF phosphorylation have been extensively studied, the phosphatases underlying PIF dephosphorylation are largely unknown. Here, we real that mutation of FyPP1 and FyPP3, two catalytic subunits of PP6 phosphatases, promoted photomorphogenesis of seedlings in the dark. PP6 and PIFs functioned synergistically to repress photomorphogenesis. FyPP1 and FyPP3 directly interacted with and dephosphorylated PIF3 and PIF4. The light-induced degradation of PIF4 and the PIF transcriptional activities were dependent on PP6 activity. These data demonstrate that PP6 phosphatases repress photomorphogenesis through regulation of PIF phosphorylation, protein stability and transcriptional activity.
Project description:A time course gene expression profiling of rice treated with various plant hormones (abscisic acid, gibberelin, auxin, brassinosteroid, cytokinin and jasmonic acid) was performed to obtain an overall signature of the rice transcriptome in response to each phytohormone.
Project description:Mitochondrial biogenesis is regulated by signaling pathways sensitive to extracellular conditions and to the internal environment of the cell. We found that deletion of protein phosphatase 2A (PP2A) or of protein phosphatase 6 (PP6) diminishes the nuclear transcriptional response associated with mtDNA damage.
Project description:Mitochondrial biogenesis is regulated by signaling pathways sensitive to extracellular conditions and to the internal environment of the cell. We found that deletion of protein phosphatase 2A (PP2A) or of protein phosphatase 6 (PP6) diminishes the nuclear transcriptional response associated with mtDNA damage. Six samples were analyzed to determine message RNA levels.
Project description:Mycobacteria have the ability to adapt to stressful infection conditions by entering a reversible state of non-replicating persistence (NRP) characterized by slow or no cell growth and increased tolerance to various antimicrobial agents. While hypoxia and nutrient deprivation are commonly used to study this NRP state, there is limited understanding of the molecular distinctions in how mycobacteria adapt to these different stresses to achieve a similar NRP outcome. In this study, we conducted a comprehensive analysis of Mycobacterium bovis BCG's response to starvation, shedding light on a coordinated metabolic shift away from glycolysis during nutrient-rich growth to the depletion of lipid stores, lipolysis, and fatty acid ß-oxidation during NRP. Interestingly, this response differs from BCG's NRP state under hypoxia, where it shifts towards cholesterol metabolism and triglyceride storage. Our investigation also unveiled hidden metabolic vulnerabilities in the NRP state induced by starvation, notably an increased sensitivity to H2O2. These findings open up possibilities for the development of precise therapeutic approaches against these otherwise challenging-to-treat pathogens.
Project description:Genome wide CRISPR/Cas9 screening identified SETDB1 and the HUSH complex as a synthetic lethal interactor of the PP6 phosphatase. Here, we sought to discover the molecular basis for this synthetic lethality. SETDB1 is a histone H3 lysine 9 methyltransferase, reported to be important in the establishment and maintenance of heterochromatin, and the silencing of repeats and incoming viral elements. We undertook RNA sequencing to explore differences in the transcriptome in HeLa and hTERT-RPE-1 cells devoid of PP6, SETDB1 or both proteins together.
