Methylation of protein phosphatase 2A—Influence of regulators and environmental stress factors

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.

Genome wide identification and functional characterization of strawberry pectin methylesterases related to fruit softening

“…For example, group 1a is the biggest subgroup with diverse functions, involved in adventitious rooting, nematode defense and seedling development in Arabidopsis [48,49], implying a similar role of FvPME in group 1a FvPME38 and two AtPME genes (AtPME9 and AtPME28) belong to subgroup 1 g-2. AtPME 9 and AtPME28 have been reported to participate in cell wall remodeling processes and response to abiotic stress [55,56]. Possibly, the homologue strawberry gene FvPME38 is also involved in cell wall regulation.…”

Defensive forwards: stress-responsive proteins in cell walls of crop plants

“…Here we just referred some examples, because we did not aim to comprehensively review previous studies. In Arabidopsis, pectinesterase 1acts as negative regulators of genes involved in salt stress response [40]; pectin methylesterase is required for guard cell function in response to heat [41]; purple acid phosphatase 17 is reducible by ABA(abscisic acid), H 2 O 2 , senescence, phosphate starvation and salt stress [42]. In rice, β-galactosidase gene responds to ABA and water-stress [43] and germin-like proteins are associated with salt stress [44].…”

Digging for Stress-Responsive Cell Wall Proteins for Developing Stress-Resistant Maize

“…In maize root tips, many CWPs, such as α-L-arabinofuranosidase, β-D-glucosidase, β-galactosidase, β-D-xylosidase, and xyloglucan endotransglucosylase/hydrolase ( Zhu et al, 2007 ), in the category of hydrolases respond to water deficit. In Arabidopsis, pectinesterase1 acts as a negative regulator of genes involved in salt stress response ( Creighton et al, 2017 ); pectin methylesterase is required for guarding the cell function in response to heat ( Wu et al, 2017 ); purple acid phosphatase 17 is reducible by ABA, H 2 O 2 , senescence, phosphate starvation, and salt stress ( Del Pozo et al, 1999 ). In rice, β-galactosidase gene responds to ABA and water-stress ( Mundy and Chua, 1988 ) and germin-like proteins are associated with salt stress ( Banerjee et al, 2017 ).…”