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This work reveals how a regulatory domain in O-GlcNAc hydrolase (OGA) shapes enzyme flexibility and activity, uncovering mechanisms that help maintain O-GlcNAc balance in cells.

Fusion of a split form of the protein O-GlcNAcase with nanobodies enables the targeted removal of O-GlcNAc protein modifications, providing a tool for probing the functional roles of specific O-GlcNAc modifications in a cellular context.

Wang et al. show how glucose sensing via O-GlcNAcylation drives the assembly of a glycolytic metabolon on the mitochondrial surface to couple metabolic efficiency with neuronal activity.

CRISPR–Cas9-based method to introduce site-specific S-GlcNAcylation enables dissection of the roles of protein O-GlcNAcylation. S-GlcNAc, a hydrolytically stable structural mimic of O-GlcNAc, is recognized by a range of O-GlcNAc-binding proteins.

Hyperammonemia occurs in liver diseases affecting ureagenesis, and is life-threatening. Here, the authors show that liver UDP-GlcNAc is increased during hyperammonemia, leading to O-GlcNAcylation of the rate-limiting ureagenesis enzyme CPS1, that enhanced ureagenesis and ammonia detoxification. They also showed that pharmacological increase of protein O-GlcNAcylation reduces hyperammonemia in mouse models of liver disease.

Misalignment between lifestyle and the natural day-night cycle, such as mistimed eating, can negatively impact health. Here the authors show that mistimed feeding alters protein O-GlcNAcylation, a nutrient sensitive post-translational modification.

Authors report drug repurposing screens against O-GlcNAc cycling enzymes, finding kinase inhibitors that act as splicing modulators to disrupt O-GlcNAc homeostasis and downregulate OGT and OGA. These findings reveal splicing modulator chemotypes and approaches to disrupt O-GlcNAc homeostasis.

Li, Lu et al. demonstrate that O-GlcNAcylation enhances angiogenic transdifferentiation from fibroblasts to endothelial cells through a HIRA-dependent H3.3 deposition mechanism and facilitates vascular regeneration.

An inactive mutant of a bacterial O-GlcNAc hydrolase was used as an affinity reagent to enrich O-GlcNAc-modified proteins from Drosophila embryos and led to the identification, by MS–proteomics, of O-GlcNAcylated proteins involved in embryogenesis.

An optogenetic tool called Opto-OGT has been developed that enables researchers to probe pathways involving modifications with O-linked β-N-acetylglucosamine (O-GlcNAc) such as OGT, mTOR and AMPK signaling with high spatiotemporal precision. The method is based on fusing a photosensitive cryptochrome protein to an O-GlcNAc transferase and enables OGT to be reversibly activated with blue light.

Many cellular proteins are reversibly modified byO-linked N-acetylglucosamine (O-GlcNAc) moieties on Ser and Thr residues. Studies on the mechanisms and functions of O-GlcNAcylation and its links to metabolism reveal the importance of this modification in the maintenance of cellular and organismal homeostasis.

α-Synuclein and tau can form multiple amyloid structures or strains that are associated with different neurodegenerative diseases, suggesting a strain–toxicity relationship. Now, it has been shown that O-GlcNAc modification of α-synuclein results in the formation of an amyloid strain that is largely nonpathogenic in vivo, supporting structure-dependent toxicity and another protective role for O-GlcNAc.

Zhang, Ma et al. report that ROS-activated O-GlcNAc transferase promotes FOXK2 O-GlcNAcylation and nuclear translocation to upregulate SLC7A11 expression, thereby modulating ferroptosis sensitivity, tumour development and chemoradiotherapy efficacy.

Peptide phage display reveals a non-catalytic binding site on the intervening domain of O-GlcNAc transferase. Its roles in substrate recognition, posttranslational modification (PTM) crosstalk and nutrient response provide insight into the function of this cryptic domain.

Crystallographic analysis of human O-GlcNAc hydrolase (hOGA) fragments containing the catalytic domain, including structures in complex with known inhibitors, suggests that OGA is functional as a dimer and defines opportunities for structure-based drug design.

Here, the authors suggest that nitric oxide (NO) is an endogenous epigenetic regulator of gene expression by inhibiting DNA demethylation enzymes (TET and ALKBH2) and increasing DNA methylation at gene regulatory loci throughout the genome.

An approach combining bioorthogonal chemistry with genetically encoded fluorogen-activating proteins enables subcellular imaging of phospholipids and glycans, as well as the visualization of lipid transport between organelles and lipid asymmetry across membrane leaflets.

Yersinia ruckeri is the source of redmouth disease in fish. Here the authors analysed the Yersiniatoxin Afp18 and show that it acts to inhibit RhoA activation by glycosylating a distinct tyrosine residue inducing a signalling incompetent structural conformation.

Intracellular proteins are regulated by multiple post-translation modifications. Cantrell and colleagues show that nutrient flux regulates intracellular protein modification by O-GlcNAcylation, which drives thymocyte development and T cell proliferation.

Feeding of modified carbohydrates has previously led to metabolic incorporation of these compounds into cellular glycans. Now the strategic use of a thiol analog that can be converted into an activated sugar but not incorporated into glycans provides a potent intracellular glycosyltransferase inhibitor.

p53 regulates signalling pathways involved in metabolic homeostasis. Here the authors show that O-GlcNAcylation of p53 in the liver plays a key role in the physiological regulation of glucose homeostasis, potentially via controlling the expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase.

DNA analysis of ancient individuals and modern populations suggests that the population history of North America can be explained by the admixture of two ancestral lineages—Palaeo-Eskimos and First Peoples.

Metabolic labeling of the Drosophila proteome using a chemical ligation approach identifies proteins modified by O-GlcNAc transferase (OGT) including Polycomb proteins at homeotic gene loci and at unexpected sites, implicating OGT in gene-expression regulation.

The post-translational modification O-GlcNAc on amyloid-forming proteins can inhibit their aggregation. Now, it has been shown that O-GlcNAc modification of small heat shock proteins HSP27, αA- and αB-crystallin can increase their anti-amyloid activity and block the amyloid formation of both α-synuclein and Aβ(1–42). A mechanism for this protective effect based on decreased physical interactions is also proposed.

Phosphoribosyl pyrophosphate synthetase (PRPS1), an enzyme that regulates de novo nucleotide synthesis, was found to be O-GlcNAcylated, which increases PRPS1 activity, and is associated with increased tumorigenesis and resistance to chemoradiotherapy.

Dissecting the often subtle or time-sensitive roles of glycans in biology demands an increased availability of high-quality inhibitors for carbohydrate-processing enzymes. A review of lessons learned from other fields and considerations unique to glycobiology provides guidelines for development of these critical chemical tools.

Glycosylation is a well-known post-translational modification, but identifying specific roles for the attached glycans is often challenging. The identification and investigation of a new O-GlcNAc site on the transcription factor CREB provides insights into how glycosylation works together with phosphorylation to coordinate neural function.

HnRNP R regulates the axonal transcriptome. Here the authors show that hnRNP R is a component of translation initiation complexes and interacts with O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (Ogt), promoting O-GlcNAcylation of eIF4G.

The limited success of amyloid-β-targeting therapies for Alzheimer disease has led to a shift in focus towards the tau protein. This Review provides an update on the initial trials of tau-targeting therapies, focusing particularly on immunotherapies, and considers future directions for these therapies.

The authors have demonstrated an important new role of protein O-GlcNAcylation in regulating pancreatic cancer TRAIL resistance; and uncovered the contribution of O-GlcNAcylation to TRAIL activation-induced oligomerization of death receptor 5 and apoptosis signaling. These findings support the potential use of O-GlcNAcylation inhibitors to enhance efficacy of TRAIL therapy.

Interest in tau-targeting strategies for Alzheimer disease is increasing, in part because of the failure of various amyloid-β-targeting treatments in clinical trials. Congdon and Sigurdsson review the current status of tau-targeting therapies, including anti-tau drugs and immunotherapies.