bims-supasi Biomed News
on Sulfation pathways and signalling
Issue of 2022‒01‒02
three papers selected by
Jonathan Wolf Mueller
University of Birmingham

  1. Gastroenterology. 2021 Dec 23. pii: S0016-5085(21)04118-4. [Epub ahead of print]
      BACKGROUND & AIMS: Sulfoconjugation of small molecules or protein peptides is a key mechanism to ensure biochemical and functional homeostasis in mammals. The PAPS synthase 2 (PAPSS2) is the primary enzyme to synthesize the universal sulfonate donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS). Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF), in which oxidative stress is a key pathogenic event, whereas sulfation of APAP contributes to its detoxification. The goal of this study is to determine whether and how PAPSS2 plays a role in APAP-induced ALF.METHODS: Gene expression was analyzed in APAP-induced ALF in patients and mice. Liver-specific Papss2 knockout mice using Alb-Cre (Papss2ΔHC) or AAV8-TBG-Cre (Papss2iΔHC) were created and subjected to APAP-induced ALF. Primary human and mouse hepatocytes were used for in vitro mechanistic analysis.
    RESULTS: The hepatic expression of PAPSS2 was decreased in APAP-induced ALF in patients and mice. Surprisingly, Papss2ΔHC mice were protected from APAP-induced hepatotoxicity despite having a decreased APAP sulfation, which was accompanied by increased hepatic antioxidative capacity through the activation of the p53-p2-Nrf2 axis. Treatment with a sulfation inhibitor also ameliorated APAP-induced hepatotoxicity. Gene knockdown experiments showed that the hepatoprotective effect of Papss2ΔHC was Nrf2-, p53- and p21-dependent. Mechanistically, we identified p53 as a novel substrate of sulfation. Papss2 ablation led to p53 protein accumulation by preventing p53 sulfation, which disrupts p53-MDM2 interaction and p53 ubiquitination, and increases p53 protein stability.
    CONCLUSIONS: We have uncovered a previously unrecognized and p53-mediated role of PAPSS2 in controlling oxidative response. Inhibition of p53 sulfation may be explored for the clinical management of APAP overdose.
    Keywords:  Acetaminophen; Oxidative hepatotoxicity; PAPSS2; Sulfation; p53
  2. Plants (Basel). 2021 Nov 26. pii: 2597. [Epub ahead of print]10(12):
      Various kinds of primary metabolisms in plants are modulated through sulfate metabolism, and sulfotransferases (SOTs), which are engaged in sulfur metabolism, catalyze sulfonation reactions. In this study, a genome-wide approach was utilized for the recognition and characterization of SOT family genes in the significant nutritional crop potato (Solanum tuberosum L.). Twenty-nine putative StSOT genes were identified in the potato genome and were mapped onto the nine S. tuberosum chromosomes. The protein motifs structure revealed two highly conserved 5'-phosphosulfate-binding (5' PSB) regions and a 3'-phosphate-binding (3' PB) motif that are essential for sulfotransferase activities. The protein-protein interaction networks also revealed an interesting interaction between SOTs and other proteins, such as PRTase, APS-kinase, protein phosphatase, and APRs, involved in sulfur compound biosynthesis and the regulation of flavonoid and brassinosteroid metabolic processes. This suggests the importance of sulfotransferases for proper potato growth and development and stress responses. Notably, homology modeling of StSOT proteins and docking analysis of their ligand-binding sites revealed the presence of proline, glycine, serine, and lysine in their active sites. An expression essay of StSOT genes via potato RNA-Seq data suggested engagement of these gene family members in plants' growth and extension and responses to various hormones and biotic or abiotic stimuli. Our predictions may be informative for the functional characterization of the SOT genes in potato and other nutritional crops.
    Keywords:  bioinformatics; potato; protein structure; stimuli coping; sulfotransferase; sulfur
  3. J Biol Chem. 2021 Dec 23. pii: S0021-9258(21)01188-1. [Epub ahead of print] 101382
      The human genome contains at least 35 genes that encode Golgi sulfotransferases that function in the secretory pathway, where they are involved in decorating glycosaminoglycans, glycolipids, and glycoproteins with sulfate groups. Although a number of important interactions by proteins such as Selectins, Galectins, and Siglecs are thought to mainly rely on sulfated O-glycans, our insight into the sulfotransferases that modify these glycoproteins, and in particular GalNAc-type O-glycoproteins, is limited. Moreover, sulfated mucins appear to accumulate in respiratory diseases, arthritis, and cancer. To explore further the genetic and biosynthetic regulation of sulfated O-glycans, here we expanded a cell-based glycan array in the human HEK293 cell line with sulfation capacities. We stably engineered O-glycan sulfation capacities in HEK293 cells by site-directed knock-in of sulfotransferase genes in combination with knockout of genes to eliminate endogenous O-glycan branching (core2 synthase gene GCNT1) and/or sialylation capacities in order to provide simplified substrates (core1 Galβ1-3GalNAcα1-O-Ser/Thr) for the introduced sulfotransferases. Expression of the galactose 3O-sulfotransferase 2 (GAL3ST2) in HEK293 cells resulted in sulfation of core1 and core2 O-glycans, whereas expression of galactose 3O-sulfotransferase 4 (GAL3ST4) resulted in sulfation of core1 only. We used the engineered cell library to dissect the binding specificity of galectin-4 and confirmed binding to the 3-O-sulfo-core1 O-glycan. This is a first step towards expanding the emerging cell-based glycan arrays with the important sulfation modification for display and production of glycoconjugates with sulfated O-glycans.
    Keywords:  Glycosylation; MUC1; O-glycans; sulfated-T; sulfated-Tn; sulfation