Arabidopsis thaliana 2,3‐bisphosphoglycerate‐independent phosphoglycerate mutase 2 activity requires serine 82 phosphorylation

Abstract

SUMMARY Phosphoglycerate mutases (PGAMs) catalyse the reversible isomerisation of 3‐phosphoglycerate and 2‐phosphoglycerate, a step of glycolysis. PGAMs can be sub‐divided into 2,3‐bisphosphoglycerate‐dependent (dPGAM) and ‐independent (iPGAM) enzymes. In plants, phosphoglycerate isomerisation is carried out by cytosolic iPGAM. Despite its crucial role in catabolism, little is known about post‐translational modifications of plant iPGAM. In Arabidopsis thaliana, phosphoproteomics analyses have previously identified an iPGAM phosphopeptide where serine 82 is phosphorylated. Here, we show that this phosphopeptide is less abundant in dark‐adapted compared to illuminated Arabidopsis leaves. In silico comparison of iPGAM protein sequences and 3D structural modelling of AtiPGAM2 based on non‐plant iPGAM enzymes suggest a role for phosphorylated serine in the catalytic reaction mechanism. This is confirmed by the activity (or the lack thereof) of mutated recombinant Arabidopsis iPGAM2 forms, affected in different steps of the reaction mechanism. We thus propose that the occurrence of the S82‐phosphopeptide reflects iPGAM2 steady‐state catalysis. Based on this assumption, the metabolic consequences of a higher iPGAM activity in illuminated versus darkened leaves are discussed.

Pien Tze Huang regulates phosphorylation of metabolic enzymes in mice of hepatocellular carcinoma

“…Our study verified that two phosphorylation sites (S14, Y132) of PGAM2 were significantly down-regulated for 1.6-fold and 2.4-fold with the treatment of PZH, for 1.3-fold and 1.6-fold by sora, this result was consistent with the reported phosphorylated sites of PGAM2 which did not show the potential impact of serine phosphorylation on enzyme activity 34 . It was reported that an Arabidopsis thaliana 2,3-bisphosphoglycerate-independent PGAM (iPGAM) phosphopeptide contained a phosphorylated serine 80 and serine 82 in iPGAM1 and iPGAM2 respectively, and it was verified that the metabolic consequences of S82 phosphorylation was a higher iPGAM enzyme activity in light-treated compared to light/dark-treated A. thaliana rosette leaves 35 . Meanwhile, it was demonstrated that the phosphorylation of tyrosine 26 residue of PGAM1 greatly enhances its activity by enhancing the binding of PGAM1 to its substrates, and thus upregulates glycolysis and promotes tumor growth 36 .…”

Transcriptomic and metabolomic changes in postharvest sugarbeet roots reveal widespread metabolic changes in storage and identify genes potentially responsible for respiratory sucrose loss

“…(2020) found a gene encoding a different TPI isozyme to have a central role among genes that were correlated with sucrose loss in stored sugarbeet roots. The phosphoglycerate-dependent isozyme of phosphoglycerate mutase (PGlyM) that correlated to respiration rate is also unlikely to have a major role in regulating glycolysis or respiration since PGlyM activity in plants is primarily due to isozymes that are not dependent on 2,3-bisphosphoglycerate as a cofactor ( Duminil et al., 2021 ).…”

“…Similarly, triosephosphate isomerase (TPI) which catalyzes interconversion of the triosephosphates, dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, is not typically regarded as a regulatory enzyme for glycolysis or respiration, although Madritsch et al (2020) found a gene encoding a different TPI isozyme to have a central role among genes that were correlated with sucrose loss in stored sugarbeet roots. The phosphoglyceratedependent isozyme of phosphoglycerate mutase (PGlyM) that correlated to respiration rate is also unlikely to have a major role in regulating glycolysis or respiration since PGlyM activity in plants is primarily due to isozymes that are not dependent on 2,3bisphosphoglycerate as a cofactor (Duminil et al, 2021).…”