Methylation of protein phosphatase 2A—Influence of regulators and environmental stress factors. (24th August 2017)

• Record Type: Journal Article
• Authors: Creighton, Maria T.; Kolton, Anna; Kataya, Amr R.A.; Maple‐Grødem, Jodi; Averkina, Irina O.; Heidari, Behzad; Lillo, Cathrine
• Is Part Of: Plant, cell and environment. Volume 40:Number 10(2017)
• Page Start: 2347
• Page End: 2358
• Publication Date: 2017-08-24
• Subjects: flowering time -- hypoxia -- LCMT -- methylation -- PME -- PP2A -- PTPA -- salt stress -- RNA‐seq; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.13038
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Protein phosphatase 2A catalytic subunit (PP2A‐C) has a terminal leucine subjected to methylation, a regulatory mechanism conserved from yeast to mammals and plants. Two enzymes, LCMT1 and PME1, methylate and demethylate PP2A‐C, respectively. The physiological importance of these posttranslational modifications is still enigmatic. We investigated these processes in Arabidopsis thaliana by mutant phenotyping, by global expression analysis, and by monitoring methylation status of PP2A‐C under different environmental conditions. The lcmt1 mutant, possessing essentially only unmethylated PP2A‐C, had less dense rosettes, and earlier flowering than wild type (WT). The pme1 mutant, with 30% reduction in unmethylated PP2A‐C, was phenotypically comparable with WT. Approximately 200 overlapping genes were twofold upregulated, and 200 overlapping genes were twofold downregulated in both lcmt1 and pme1 relative to WT. Differences between the 2 mutants were also striking; 97 genes were twofold upregulated in pme1 compared with lcmt1, indicating that PME1 acts as a negative regulator for these genes. Analysis of enriched GO terms revealed categories of both abiotic and biotic stress genes. Furthermore, methylation status of PP2A‐C was influenced by environmental stress, especially by hypoxia and salt stress, which led to increased levels of unmethylated PP2A‐C, and highlights the importance of PP2A‐C methylation/demethylation in environmental responses. Abstract : Protein phosphatase 2A (PP2A) is methylated and demethylated at the terminal leucine by LCMT1 and PME1, respectively. Hypoxia and salt stress promoted a high level of unmethylated PP2A. RNA‐seq revealed that high levels of methylated PP2A ( pme1 mutant) were linked with induction of several transcription factors and genes but no striking phenotype, whereas high levels of unmethylated PPA ( lcmt1 mutant) were linked with inhibition of gene expression, early flowering, reduced root growth, and slender rosettes.