Regulating the Regulators: Mechanisms of Substrate Selection of the O-GlcNAc Cycling Enzymes OGT and OGA

Stephen, Hannah; Adams, Trevor M; Wells, Lance

doi:10.1093/glycob/cwab005

Cited by 50 publications

(41 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…O-Linked N-acetyl glucosamine (O-GlcNAc) is a monosaccharide post-translational modification installed on serine or threonine residues of thousands of nucleocytoplasmic proteins across multiple species [1]. O-GlcNAc is a dynamic and reversible modification that is regulated by a pair of essential enzymes, the writer O-GlcNAc transferase (OGT) and the eraser O-GlcNAcase (OGA) [2,3]. Regulatory maintenance of O-GlcNAc levels in the proteome is critical for normal cellular physiology as loss of either OGT or OGA disrupts cellular growth and limits organismal survival [4,5], and disruptions to O-GlcNAc homeostasis have been linked to genetic diseases (e.g., X-linked intellectual disability) [6] and various chronic diseases, including neurodegeneration [7], diabetes [8], and cancer [9].…”

Section: Introductionmentioning

confidence: 99%

Truncation of the TPR domain of OGT alters substrate and glycosite selection

et al. 2021

View full text Add to dashboard Cite

O-GlcNAc transferase (OGT) is an essential enzyme that installs O-linked N-acetylglucosamine (O-GlcNAc) to thousands of protein substrates. OGT and its isoforms select from these substrates through the tetratricopeptide repeat (TPR) domain, yet the impact of truncations to the TPR domain on substrate and glycosite selection is unresolved. Here, we report the effects of iterative truncations to the TPR domain of OGT on substrate and glycosite selection with the model protein GFP-JunB and the surrounding O-GlcNAc proteome in U2OS cells. Iterative truncation of the TPR domain of OGT maintains glycosyltransferase activity but alters subcellular localization of OGT in cells. The glycoproteome and glycosites modified by four OGT TPR isoforms were examined on the whole proteome and a single target protein, GFP-JunB. We found the greatest changes in O-GlcNAc on proteins associated with mRNA splicing processes and that the first four TPRs of the canonical nucleocytoplasmic OGT had the broadest substrate scope. Subsequent glycosite analysis revealed that alteration to the last four TPRs corresponded to the greatest shift in the resulting O-GlcNAc consensus sequence. This dataset provides a foundation to analyze how perturbations to the TPR domain and expression of OGT isoforms affect the glycosylation of substrates, which will be critical for future efforts in protein engineering of OGT, the biology of OGT isoforms, and diseases associated with the TPR domain of OGT.

show abstract

Section: Introductionmentioning

confidence: 99%

Truncation of the TPR domain of OGT alters substrate and glycosite selection

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The OGA dimer forms a V-shaped cleft at the interface of the catalytic domain and stalk domain of the two monomers, providing a potential substrate binding pocket. For a more detailed discussion on OGT and OGA substrate specificity see (47).…”

Section: O-glcnacase (Oga)mentioning

confidence: 99%

The Beginner’s Guide to O-GlcNAc: From Nutrient Sensitive Pathway Regulation to Its Impact on the Immune System

Mannino

Hart

2022

Front. Immunol.

View full text Add to dashboard Cite

The addition of N-acetyl glucosamine (GlcNAc) on the hydroxy group of serine/threonine residues is known as O-GlcNAcylation (OGN). The dynamic cycling of this monosaccharide on and off substrates occurs via O-linked β-N-acetylglucosamine transferase (OGT) and O-linked β-N-acetylglucosaminase (OGA) respectively. These enzymes are found ubiquitously in eukaryotes and genetic knock outs of the ogt gene has been found to be lethal in embryonic mice. The substrate scope of these enzymes is vast, over 15,000 proteins across 43 species have been identified with O-GlcNAc. OGN has been known to play a key role in several cellular processes such as: transcription, translation, cell signaling, nutrient sensing, immune cell development and various steps of the cell cycle. However, its dysregulation is present in various diseases: cancer, neurodegenerative diseases, diabetes. O-GlcNAc is heavily involved in cross talk with other post-translational modifications (PTM), such as phosphorylation, acetylation, and ubiquitination, by regulating each other’s cycling enzymes or directly competing addition on the same substrate. This crosstalk between PTMs can affect gene expression, protein localization, and protein stability; therefore, regulating a multitude of cell signaling pathways. In this review the roles of OGN will be discussed. The effect O-GlcNAc exerts over protein-protein interactions, the various forms of crosstalk with other PTMs, and its role as a nutrient sensor will be highlighted. A summary of how these O-GlcNAc driven processes effect the immune system will also be included.

show abstract

“…Through microinjection of a fosmid into this strain, we established two independent lines carrying a fosmid containing the ogt-1 gene as an extrachromosomal array. Males with the fosmid had wild-type fertility when mated with fem-1 worms (Fig 1B [5][6]. As an extrachromosomal array, expression of the ogt-1 transgene was likely repressed in the germline [39], and we used antibody staining on the gonad and intestine of dissected males to test this.…”

Section: Ogt-1 Is Required For Male Fertilitymentioning

confidence: 99%

“…OGT transfers O- GlcNAc to serine and threonine residues of its protein targets to regulate many processes within cells. This post-translational modification is added to thousands of nucleocytoplasmic proteins, and can be dynamically removed by the O- GlcNAcase (OGA) [6, 7]. O- GlcNAc modification of proteins can modify their activity, subcellular localization, and interactions with other proteins [7, 8].…”

Section: Introductionmentioning

confidence: 99%

O-GlcNAc transferase plays a non-catalytic role in C. elegans male fertility

Konzman

Fukushige

Dagnachew

et al. 2022

Preprint

View full text Add to dashboard Cite

Animal behavior is influenced by the competing drives to maintain energy and to reproduce. The balance between these evolutionary pressures and how nutrient signaling pathways intersect with mating drive remains unclear. The nutrient sensor O-GlcNAc transferase, which post-translationally modifies intracellular proteins with a single monosaccharide, is responsive to cellular nutrient status and regulates diverse biological processes. Though essential in most metazoans, O-GlcNAc transferase (ogt-1) is dispensable in Caenorhabditis elegans, allowing genetic analysis of its physiological roles. Compared to control, ogt-1 males have a four-fold reduction in mean offspring, with nearly two thirds producing zero progeny. Interestingly, we found that isolated ogt-1 males are less likely to engage in mate-searching, and they initiate mating less often when exposed to mates. In addition, ogt-1 males which do initiate mating are less likely to continue with subsequent steps in the mating process, resulting in fewer successful sperm transfers. Lowering barriers to mating such as immobilizing mates or allowing more mating time significantly improves ogt-1 male mating. Surprisingly, we found high fertility levels for ogt-1 mutant males with hypodermal expression of wild-type ogt-1 and by ogt-1 harboring mutations that prevent the transfer of O-GlcNAc by OGT-1. This suggests OGT-1 serves a non-catalytic function in the hypodermis impacting the male mating drive. This study builds upon research on the nutrient sensor O-GlcNAc transferase and demonstrates a role it plays in the interplay between the evolutionary drives for reproduction and survival.

show abstract

Regulating the Regulators: Mechanisms of Substrate Selection of the O-GlcNAc Cycling Enzymes OGT and OGA

Cited by 50 publications

References 66 publications

Truncation of the TPR domain of OGT alters substrate and glycosite selection

Truncation of the TPR domain of OGT alters substrate and glycosite selection

The Beginner’s Guide to O-GlcNAc: From Nutrient Sensitive Pathway Regulation to Its Impact on the Immune System

O-GlcNAc transferase plays a non-catalytic role in C. elegans male fertility

Contact Info

Product

Resources

About