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o Glcnac

Kecheng Li, Andrew Green, Meredith M Dinges, Cynthia K Larive
Chitin oligosaccharides, composed of homogeneous β(1 → 4)-linked N-acetyl-D-glucosamine (GlcNAc) sequences, is a well-known elicitor of plant immune defense, and also occur as structural elements of chitosan and nodulation (Nod) factor. Detailed microstructure characterization is required for understanding the function mode of these bioactive molecules. Herein, experimental conditions for detection and elucidation of the 1 H NMR resonances of amide groups in chitin oligosaccharides are presented. The binary mixture of 70% H2 O: 30% DMSO‑d6 was found to be the optimal solvent for amide proton measurements in homogeneous GlcNAc sequences, facilitating differentiation of the local chemical microenvironments of all four amide groups of the chitin tetrasaccharide...
February 13, 2019: International Journal of Biological Macromolecules
Xinghui Li, Wei Gong, Hao Wang, Tianliang Li, Kuldeep S Attri, Robert E Lewis, Andre C Kalil, Fatema Bhinderwala, Robert Powers, Guowei Yin, Laura E Herring, John M Asara, Yu L Lei, Xiaoyong Yang, Diego A Rodriguez, Mao Yang, Douglas R Green, Pankaj K Singh, Haitao Wen
Elevated glucose metabolism in immune cells represents a hallmark feature of many inflammatory diseases, such as sepsis. However, the role of individual glucose metabolic pathways during immune cell activation and inflammation remains incompletely understood. Here, we demonstrate a previously unrecognized anti-inflammatory function of the O-linked β-N-acetylglucosamine (O-GlcNAc) signaling associated with the hexosamine biosynthesis pathway (HBP). Despite elevated activities of glycolysis and the pentose phosphate pathway, activation of macrophages with lipopolysaccharide (LPS) resulted in attenuated HBP activity and protein O-GlcNAcylation...
February 5, 2019: Immunity
Sicheng Gao, Yun Miao, Yijie Liu, Xing Liu, Xingliang Fan, Yan Lin, Pingan Qian, Jun Zhou, Yaoyao Dai, Li Xia, Po Zhu, Junfeng Zhu
Abnormal expression of O-Linked β-N-acetylglucosamine (O-GlcNAc) and β-catenin is a general feature of cancer and contributes to transformed phenotypes. In this study, we identified the interaction between O-GlcNAc and β-catenin, and explored their effects on the progression of liver cancer. Our results demonstrated that upregulation of O-GlcNAc was induced by high glucose, whereas the application of PuGNAc and GlcNAc increased β-catenin protein expression levels, as well as the protein's stability and nuclear accumulation in the liver cancer cell lines HEP-G2 and HuH-7...
February 14, 2019: DNA and Cell Biology
Shanwen Ke, Shuchun Liu, Xin Luan, Xin-Ming Xie, Tzung-Fu Hsieh, Xiang-Qian Zhang
Leaf senescence is a genetically regulated, highly complex and ordered process. Although it has been extensively studied, the mechanism of leaf senescence is not well understood. In this study, we isolated a rice mutant, designated as premature senescence leaf (psl), which exhibits early senescence and spontaneous lesion mimic phenotype after flowering. The psl mutant displays programmed cell death with elevated accumulation of reactive oxygen species (ROS). Molecular and genetic analyses revealed that the phenotypes were caused by a phenylalanine deletion in the OsPSL (LOC_Os12g42420) that encode a putative core 2/I branching beta-1,6-N-acetylglucosaminyl transferase predicted to be involved in protein glycosylation modification...
February 13, 2019: Rice
Sadie K Dierschke, William P Miller, John S Favate, Premal Shah, Yuka Imamura Kawasawa, Anna C Salzberg, Scot R Kimball, Leonard S Jefferson, Michael D Dennis
Diabetes promotes the post-translational modification of proteins by O-linked addition of N-acetylglucosamine (O-GlcNAcylation) to Ser/Thr residues of proteins and thereby contributes to diabetic complications. In the retina of diabetic mice, the repressor of mRNA translation eIF4E-binding protein 1 (4E-BP1) is O-GlcNAcylated and sequestration of the cap-binding protein eukaryotic translation initiation factor (eIF4E) is enhanced. O-GlcNAcylation has also been detected on several eukaryotic translation initiation factors and ribosomal proteins...
February 7, 2019: Journal of Biological Chemistry
Suhela Sharif, Jie Shi, Rob Ruijtenbeek, Roland J Pieters
O-GlcNAcylation, like phosphorylation, is a dynamic and rapid posttranslational modification which regulates many cellular processes. Phosphorylation on tyrosine and O-GlcNAcylation on nearby serine or threonine residues may modulate each other. Indeed, by using a microarray with a peptide model system based on the ZO-3 protein, extensive cross talk between O-GlcNAcylation by OGT and phosphorylation by kinases was observed. However, studying the effects of kinases and OGT without the reverse processes catalyzed by phosphatases and O-GlcNAcase (OGA) does not provide a complete picture of the cross talk...
February 6, 2019: Amino Acids
Guoqing Zhu, Mingping Qian, Liesheng Lu, Yan Chen, Xiao Zhang, Qi Wu, Ya Liu, Zhixuan Bian, Yueyue Yang, Susu Guo, Jiayi Wang, Qiuhui Pan, Fenyong Sun
Emerging studies have revealed that O-GlcNAcylation plays pivotal roles in the tumorigenesis of colorectal cancers. However, the underlying mechanism still remains largely unknown. Here, we demonstrated that YY1 was O-GlcNAcylated by OGT and O-GlcNAcylation of YY1 could increase the protein expression by enhancing its stability. O-GlcNAcylation facilitated transformative phenotypes of CRC cell in a YY1-dependent manner. Also, O-GlcNAcylation stimulates YY1-dependent transcriptional activity. Besides, we also identified the oncoproteins, SLC22A15 and AANAT, which were regulated by YY1 directly, are responsible for the YY1 stimulated tumorigenesis...
January 30, 2019: Carcinogenesis
Haifeng Wang, Jianshuang Guo, Nan Wang, Jiajia Wang, Qingqing Xue, Jiyan Wang, Wenjie Liu, Kaihui Liu, Xuefeng Cao, Wei Zhao, Rimo Xi, Youhong Niu, Peng Wang, Jing Li
O-Linked N-acetylglucosamine (O-GlcNAc) is an abundant posttranslationalmonosaccaride-modification found on Ser or Thr residues of intracellular proteins in most eukaryotes. The dynamic nature of O-GlcNAc has enabled researchers to modulate the stoichiometry of O-GlcNAc on proteins in order to investigate its function. Cell permeable small moleculars have proven invaluable tools to increase O-GlcNAc levels. Herein, using in vitro substrate screening, we identified GlcNAcF3 as an OGT-accepted but OGA-resistant sugar mimic...
January 22, 2019: Bioorganic & Medicinal Chemistry Letters
Yan Gao, Jingfang Liu, Zhenzhong Bai, Sandy Sink, Chengyu Zhao, Felipe Ramos Lorenzo, Donald A McClain
We previously reported that iron down-regulates transcription of the leptin gene by increasing occupancy of phosphorylated cyclic AMP response element-binding protein (pCREB)2 at two sites in the leptin gene promoter. Several nutrient-sensing pathways including O-GlcNAcylation also regulate leptin. We therefore investigated if O-glycosylation plays a role in iron- and CREB-mediated regulation of leptin. We found that high iron decreases protein O-GlcNAcylation both in cultured 3T3L1 adipocytes and in mice fed high-iron diets and down-regulates leptin mRNA and protein levels...
February 1, 2019: Journal of Biological Chemistry
Cassandra M Joiner, Hao Li, Jiaoyang Jiang, Suzanne Walker
Dysregulation of nuclear and cytoplasmic O-linked β-N-acetylglucosamine (O-GlcNAc) cycling is implicated in a range of diseases including diabetes and cancer. This modification maintains cellular homeostasis by regulating several biological processes, such as cell signaling. This highly regulated cycle is governed by two sole essential enzymes, O-GlcNAc transferase and O-GlcNAcase that add O-GlcNAc and remove it from over a thousand substrates, respectively. Until recently, due to lack of structural information, the mechanism of substrate recognition has eluted researchers...
January 29, 2019: Current Opinion in Structural Biology
Rebecca A Sager, Mark R Woodford, Sarah J Backe, Alan M Makedon, Alexander J Baker-Williams, Bryanna T DiGregorio, David R Loiselle, Timothy A Haystead, Natasha E Zachara, Chrisostomos Prodromou, Dimitra Bourboulia, Laura S Schmidt, W Marston Linehan, Gennady Bratslavsky, Mehdi Mollapour
The molecular chaperone Hsp90 stabilizes and activates client proteins. Co-chaperones and post-translational modifications tightly regulate Hsp90 function and consequently lead to activation of clients. However, it is unclear whether this process occurs abruptly or gradually in the cellular context. We show that casein kinase-2 phosphorylation of the co-chaperone folliculin-interacting protein 1 (FNIP1) on priming serine-938 and subsequent relay phosphorylation on serine-939, 941, 946, and 948 promotes its gradual interaction with Hsp90...
January 29, 2019: Cell Reports
R Jitschin, M Böttcher, D Saul, S Lukassen, H Bruns, R Loschinski, A B Ekici, A Reis, A Mackensen, D Mougiakakos
Mesenchymal stem cells (MSCs) represent key contributors to tissue homeostasis and promising therapeutics for hyperinflammatory conditions including graft-versus-host disease. Their immunomodulatory effects are controlled by microenvironmental signals. The MSCs' functional response towards inflammatory cues is known as MSC-"licensing" and includes indoleamine 2,3-dioxygenase (IDO) upregulation. MSCs use tryptophan-depleting IDO to suppress T-cells. Increasing evidence suggests that several functions are (co-)determined by the cells' metabolic commitment...
January 24, 2019: Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K
Benjin Cao, Meng Duan, Yang Xing, Chanjuan Liu, Fan Yang, Yinan Li, Tianxiao Yang, Yuanyan Wei, Qiang Gao, Jianhai Jiang
O-GlcNAcylation catalysed by O-GlcNAc transferase (OGT) is a reversible post-translational modification. O-GlcNAcylation participates in transcription, epigenetic regulation, and intracellular signalling. Dysregulation of O-GlcNAcylation in response to high glucose or OGT expression has been implicated in metabolic diseases and cancer. However, the underlying mechanisms by which OGT regulates hepatoma development remain largely unknown. Here, we employed the lentiviral shRNA-based system to knockdown OGT to analyse the contribution of OGT in hepatoma cell proliferation and stem-like cell potential...
January 24, 2019: Journal of Cellular and Molecular Medicine
Réka Mócsai, Rudolf Figl, Clemens Troschl, Richard Strasser, Elisabeth Svehla, Markus Windwarder, Andreas Thader, Friedrich Altmann
Microalgae of the genus Chlorella vulgaris are candidates for the production of lipids for biofuel production. Besides that, Chlorella vulgaris is marketed as protein and vitamin rich food additive. Its potential as a novel expression system for recombinant proteins inspired us to study its asparagine-linked oligosaccharides (N-glycans) by mass spectrometry, chromatography and gas chromatography. Oligomannosidic N-glycans with up to nine mannoses were the structures found in culture collection strains as well as several commercial products...
January 23, 2019: Scientific Reports
Rebekka Vibjerg Jensen, Ioanna Andreadou, Derek J Hausenloy, Hans Erik Bøtker
Ischemia reperfusion injury (IR injury) associated with ischemic heart disease contributes significantly to morbidity and mortality. O-linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification that plays an important role in numerous biological processes, both in normal cell functions and disease. O-GlcNAc increases in response to stress. This increase mediates stress tolerance and cell survival, and is protective. Increasing O-GlcNAc is protective against IR injury. Experimental cellular and animal models, and also human studies, have demonstrated that protection against IR injury by ischemic preconditioning, and the more clinically applicable remote ischemic preconditioning, is associated with increases in O-GlcNAc levels...
January 18, 2019: International Journal of Molecular Sciences
Mitsutaka Ogawa, Tetsuya Okajima
Extracellular O-GlcNAc is a unique modification restricted to the epidermal growth factor (EGF) domain-containing glycoproteins. This O-GlcNAcylation is catalyzed by the EGF-domain specific O-GlcNAc transferase (EOGT), which is localized in the lumen of endoplasmic reticulum. In humans, EOGT is one of the causative genes of a congenital disease, Adams-Oliver syndrome. EOGT is highly expressed in endothelial cells and regulates vascular development and integrity by potentiating Delta-like ligand-mediated Notch signaling...
January 19, 2019: Current Opinion in Structural Biology
Bing Liu, Oscar C Salgado, Sangya Singh, Keli L Hippen, Jason C Maynard, Alma L Burlingame, Lauren E Ball, Bruce R Blazar, Michael A Farrar, Kristin A Hogquist, Hai-Bin Ruan
Regulatory T (Treg) cells control self-tolerance, inflammatory responses and tissue homeostasis. In mature Treg cells, continued expression of FOXP3 maintains lineage identity, while T cell receptor (TCR) signaling and interleukin-2 (IL-2)/STAT5 activation support the suppressive effector function of Treg cells, but how these regulators synergize to control Treg cell homeostasis and function remains unclear. Here we show that TCR-activated posttranslational modification by O-linked N-Acetylglucosamine (O-GlcNAc) stabilizes FOXP3 and activates STAT5, thus integrating these critical signaling pathways...
January 21, 2019: Nature Communications
Junfeng Ma, Weihan Wang, Zengxia Li, Jeffrey Shabanowitz, Donald F Hunt, Gerald W Hart
As a dynamic post-translational modification, O-linked β-N-acetylglucosamine (O-GlcNAc) modification (i.e., O-GlcNAcylation) of proteins regulates many biological processes involving cellular metabolism and signaling. However, O-GlcNAc site mapping, a prerequisite for site-specific functional characterization, has been a challenge since its discovery. Herein we present a novel method for O-GlcNAc enrichment and site mapping. In this method, the O-GlcNAc moiety on peptides is labeled with UDP-GalNAz followed by Cu-free azide-alkyne cycloaddition with a multifunctional reagent bearing a terminal cyclooctyne, a disulfide bridge, and a biotin handle...
January 18, 2019: Analytical Chemistry
Eri Tabata, Akinori Kashimura, Maiko Uehara, Satoshi Wakita, Masayoshi Sakaguchi, Yasusato Sugahara, Terumi Yurimoto, Erika Sasaki, Vaclav Matoska, Peter O Bauer, Fumitaka Oyama
Chitin is a polymer of N-acetyl-D-glucosamine (GlcNAc) and a main constituent of insects' exoskeleton. Insects are rich in protein with high energy conversion efficiency. Recently, we have reported that acidic chitinases (Chia) act as digestive enzymes in mouse, pig and chicken (omnivorous) but not in dog (carnivorous) and bovine (herbivorous), indicating that feeding behavior affects Chia expression levels, and determines chitin digestibility in the particular animals. Common marmoset (Callithrix jacchus) belongs to New World monkey family and provides a potential bridge between mouse models and human diseases...
January 17, 2019: Scientific Reports
Paul M Levine, Ana Galesic, Aaron T Balana, Anne-Laure Mahul-Mellier, Mariana X Navarro, Cesar A De Leon, Hilal A Lashuel, Matthew R Pratt
A compelling link is emerging between the posttranslational modification O-GlcNAc and protein aggregation. A prime example is α-synuclein, which forms toxic aggregates that are associated with neurodegeneration in Parkinson's and related diseases. α-Synuclein has been shown to be O-GlcNAcylated at nine different positions in in vivo proteomics experiments from mouse and human tissues. This raises the possibility that O-GlcNAc may alter the aggregation of this protein and could be both an important biological mediator of neurodegeneration and also a therapeutic target...
January 29, 2019: Proceedings of the National Academy of Sciences of the United States of America
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