Role of O-Linked N-acetylglucosamine (O-GlcNAc) Protein Modification in Cellular (Patho)Physiology

Author(s):  
John C. Chatham ◽  
Jianhua Zhang ◽  
Adam Raymond Wende

In the mid 1980s, the identification of serine and threonine residues on nuclear and cytoplasmic proteins modified by an O-linkage by a N-acetylglucosamine moiety (O-GlcNAc) overturned the widely held assumption that glycosylation only occurred in the endoplasmic reticulum, Golgi apparatus, and secretory pathways. In contrast to traditional glycosylation, the O-GlcNAc modification does not lead to complex branched glycan structures and is rapidly cycled on and off proteins by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. Since its discovery O-GlcNAcylation has been shown to contribute to numerous cellular functions including signaling, protein localization and stability, transcription, chromatin remodeling, mitochondrial function, and cell survival. Dysregulation in O-GlcNAc cycling has been implicated in the progression of a wide range of diseases such as diabetes, diabetic complications, cancer, cardiovascular, and neurodegenerative diseases. This review will outline our current understanding of the processes involved in regulating O-GlcNAc turnover, the role of O-GlcNAcylation in regulating cellular physiology, and how dysregulation in O-GlcNAc cycling contributes to pathophysiological processes.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1586
Author(s):  
Salinee Jantrapirom ◽  
Luca Lo Piccolo ◽  
Dumnoensun Pruksakorn ◽  
Saranyapin Potikanond ◽  
Wutigri Nimlamool

Ubiquilins or UBQLNs, members of the ubiquitin-like and ubiquitin-associated domain (UBL-UBA) protein family, serve as adaptors to coordinate the degradation of specific substrates via both proteasome and autophagy pathways. The UBQLN substrates reveal great diversity and impact a wide range of cellular functions. For decades, researchers have been attempting to uncover a puzzle and understand the role of UBQLNs in human cancers, particularly in the modulation of oncogene’s stability and nucleotide excision repair. In this review, we summarize the UBQLNs’ genetic variants that are associated with the most common cancers and also discuss their reliability as a prognostic marker. Moreover, we provide an overview of the UBQLNs networks that are relevant to cancers in different ways, including cell cycle, apoptosis, epithelial-mesenchymal transition, DNA repairs and miRNAs. Finally, we include a future prospective on novel ubiquilin-based cancer therapies.



F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 2016 ◽  
Author(s):  
Meghan M Kozub ◽  
Ryan M Carr ◽  
Gwen L Lomberk ◽  
Martin E Fernandez-Zapico

Histone-modifying enzymes play a critical role in chromatin remodeling and are essential for influencing several genome processes such as gene expression and DNA repair, replication, and recombination. The discovery of lysine-specific demethylase 1 (LSD1), the first identified histone demethylase, dramatically revolutionized research in the field of epigenetics. LSD1 plays a pivotal role in a wide range of biological operations, including development, cellular differentiation, embryonic pluripotency, and disease (for example, cancer). This mini-review focuses on the role of LSD1 in chromatin regulatory complexes, its involvement in epigenetic changes throughout development, and its importance in physiological and pathological processes.



2020 ◽  
Vol 21 (18) ◽  
pp. 6686
Author(s):  
Yu Ah Hong ◽  
Ji Eun Kim ◽  
Minjee Jo ◽  
Gang-Jee Ko

Sirtuins (SIRTs) are class III histone deacetylases (HDACs) that play important roles in aging and a wide range of cellular functions. Sirtuins are crucial to numerous biological processes, including proliferation, DNA repair, mitochondrial energy homeostasis, and antioxidant activity. Mammals have seven different sirtuins, SIRT1–7, and the diverse biological functions of each sirtuin are due to differences in subcellular localization, expression profiles, and cellular substrates. In this review, we summarize research advances into the role of sirtuins in the pathogenesis of various kidney diseases including acute kidney injury, diabetic kidney disease, renal fibrosis, and kidney aging along with the possible underlying molecular mechanisms. The available evidence indicates that sirtuins have great potential as novel therapeutic targets for the prevention and treatment of kidney diseases.



2009 ◽  
Vol 296 (1) ◽  
pp. H13-H28 ◽  
Author(s):  
Boglarka Laczy ◽  
Bradford G. Hill ◽  
Kai Wang ◽  
Andrew J. Paterson ◽  
C. Roger White ◽  
...  

The posttranslational modification of serine and threonine residues of nuclear and cytoplasmic proteins by the O-linked attachment of the monosaccharide β- N-acetylglucosamine ( O-GlcNAc) is a highly dynamic and ubiquitous protein modification. Protein O-GlcNAcylation is rapidly emerging as a key regulator of critical biological processes including nuclear transport, translation and transcription, signal transduction, cytoskeletal reorganization, proteasomal degradation, and apoptosis. Increased levels of O-GlcNAc have been implicated as a pathogenic contributor to glucose toxicity and insulin resistance, which are both major hallmarks of diabetes mellitus and diabetes-related cardiovascular complications. Conversely, there is a growing body of data demonstrating that the acute activation of O-GlcNAc levels is an endogenous stress response designed to enhance cell survival. Reports on the effect of altered O-GlcNAc levels on the heart and cardiovascular system have been growing rapidly over the past few years and have implicated a role for O-GlcNAc in contributing to the adverse effects of diabetes on cardiovascular function as well as mediating the response to ischemic injury. Here, we summarize our present understanding of protein O-GlcNAcylation and its effect on the regulation of cardiovascular function. We examine the pathways regulating protein O-GlcNAcylation and discuss, in more detail, our understanding of the role of O-GlcNAc in both mediating the adverse effects of diabetes as well as its role in mediating cellular protective mechanisms in the cardiovascular system. In addition, we also explore the parallels between O-GlcNAc signaling and redox signaling, as an alternative paradigm for understanding the role of O-GlcNAcylation in regulating cell function.



2003 ◽  
Vol 12 (3) ◽  
pp. 179-183 ◽  
Author(s):  
E. Jablonska ◽  
M. Marcinczyk

Background:Available data indicate that neutrophils (PMN) produce a wide range of cytokines with the potential to modulate immune response. Recent investigation have shown that interleukin (IL)-15 and IL-18 potentiated several functions of normal neutrophils. It has been reported that IL-18-induced cytokine production may be significantly enhanced by coincident addition of IL-15.Aims:In the present study we compared the effect of recombinant human (rh)IL-15 and rhIL-18 as well as effect of a rhIL-15 and rhIL-18 combination on the induction secretion of sIL-6Rα and sgp130 by human neutrophils. Methods: PMN were isolated from heparinized whole blood of healthy persons. The PMN were cultured for 18 h at 37°C in a humidified incubator with 5% CO2. rhIL-15 and/or rhIL-18 and lipopolysaccharide were tested to PMN stimulation. The culture supernatants of PMN were removed and examined for the presence of sIL-6R and sgp130 by human enzyme-linked immunosorbent assay kits. Cytoplasmic protein fractions of PMN were analysed for the presence of sIL-6R and sgp130 by western blotting using monoclonal antibodies capable of detecting these proteins. Cells were lysed and cytoplasmic proteins were electrophoresed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The resolved proteins were transferred onto nitrocellulose and incubated with the primary monoclonal antibodies anti-sIL-6R and anti-sgp130. The membranes were incubated at room temperature with alkaline phosphatase anti-mouse immunoglobulin G. Immunoreactive protein bans were visualized by an AP Conjugate Substrate Kit.Results and conclusion:The results of our investigation revealed that IL-15 alone, similarly to IL-18, has no significant ability for the regulation of both soluble IL-6 receptors, sIL-6R and sgp130, released by human neutrophils. It is interesting to note that the secretion of sgp130 was changed after PMN stimulation with rhIL-15 in the presence of rhIL-18. The combination of rhIL-15 and rhIL-18 was shown to induce PMN to secretion relatively higher amounts of sgp130 compared with the stimulation of PMN with rhIL-15 alone and rhIL-18 alone. The results obtained suggest that IL-15 and IL-18, belonging to the inflammatory cytokines, through the regulation of sgp130 secretion must be also considered as anti-inflammatory mediators that may influence the balance reactions mediated by the IL-6 cytokine family.



2007 ◽  
Vol 18 (5) ◽  
pp. 1850-1860 ◽  
Author(s):  
Akiyuki Takaya ◽  
Takahiro Kamio ◽  
Michitaka Masuda ◽  
Naoki Mochizuki ◽  
Hirofumi Sawa ◽  
...  

R-Ras is a Ras-family small GTPase that regulates various cellular functions such as apoptosis and cell adhesion. Here, we demonstrate a role of R-Ras in exocytosis. By the use of specific anti-R-Ras antibody, we found that R-Ras was enriched on both early and recycling endosomes in a wide range of cell lines. Using a fluorescence resonance energy transfer-based probe for R-Ras activity, R-Ras activity was found to be higher on endosomes than on the plasma membrane. This high R-Ras activity on the endosomes correlated with the accumulation of an R-Ras effector, the Rgl2/Rlf guanine nucleotide exchange factor for RalA, and also with high RalA activity. The essential role played by R-Ras in inducing high levels of RalA activity on the endosomes was evidenced by the short hairpin RNA (shRNA)-mediated suppression of R-Ras and by the expression of R-Ras GAP. In agreement with the reported role of RalA in exocytosis, the shRNA of either R-Ras or RalA was found to suppress calcium-triggered exocytosis in PC12 pheochromocytoma cells. These data revealed that R-Ras activates RalA on endosomes and that it thereby positively regulates exocytosis.



2014 ◽  
Vol 13 (3) ◽  
pp. 91-99 ◽  
Author(s):  
V. A. Kutyakov ◽  
A. V. Salmina

The basic information on the classification, structure, induction and degradation, functions of the protein family – metallothionein (MT), including CNS in health and disease are presented in this review. It was found that four major isoforms of metallothionein perform different biological roles, are localized in dif- ferent tissues. Induction of MT is a universal reaction to the impact of a variety of stress factors. In recent years, understanding of the role of metallothioneins in metal homeostasis in the tissues in normal and pathological conditions have changed significantly. Notes polyfunctionality metallothioneins (transport of metal ions, maintaining redox reactions, tread, signal, modulated and regulatory functions) and their im- pact on basic cellular functions such as proliferation, differentiation, programmed cell death. Further- more, a special role is shown MT in the pathogenesis of cardiovascular, neurodegenerative and neoplastic disorders.Currently, these molecules are increasingly considered as potential targets for therapy of a wide range of diseases and the development of targeted approaches to the regulation of expression of MT – one of the promising areas of pharmacology and toxicology. Stressed the safety of metallothioneins as therapeutic agents.



2021 ◽  
Vol 11 ◽  
Author(s):  
Abel Tesfaye Anshabo ◽  
Robert Milne ◽  
Shudong Wang ◽  
Hugo Albrecht

Cyclin-dependent kinases (CDKs) are proteins pivotal to a wide range of cellular functions, most importantly cell division and transcription, and their dysregulations have been implicated as prominent drivers of tumorigenesis. Besides the well-established role of cell cycle CDKs in cancer, the involvement of transcriptional CDKs has been confirmed more recently. Most cancers overtly employ CDKs that serve as key regulators of transcription (e.g., CDK9) for a continuous production of short-lived gene products that maintain their survival. As such, dysregulation of the CDK9 pathway has been observed in various hematological and solid malignancies, making it a valuable anticancer target. This therapeutic potential has been utilized for the discovery of CDK9 inhibitors, some of which have entered human clinical trials. This review provides a comprehensive discussion on the structure and biology of CDK9, its role in solid and hematological cancers, and an updated review of the available inhibitors currently being investigated in preclinical and clinical settings.



2021 ◽  
Vol 7 (1) ◽  
pp. 16
Author(s):  
Didem Karakas ◽  
Bulent Ozpolat

Long non-coding RNAs (lncRNAs), a group of non-protein coding RNAs with lengths of more than 200 nucleotides, exert their effects by binding to DNA, mRNA, microRNA, and proteins and regulate gene expression at the transcriptional, post-transcriptional, translational, and post-translational levels. Depending on cellular location, lncRNAs are involved in a wide range of cellular functions, including chromatin modification, transcriptional activation, transcriptional interference, scaffolding and regulation of translational machinery. This review highlights recent studies on lncRNAs in the regulation of protein translation by modulating the translational factors (i.e, eIF4E, eIF4G, eIF4A, 4E-BP1, eEF5A) and signaling pathways involved in this process as wells as their potential roles as tumor suppressors or tumor promoters.



1999 ◽  
Vol 77 (4) ◽  
pp. 299-309 ◽  
Author(s):  
Carole Kretz-Remy ◽  
Robert M Tanguay

Regulation of protein functions can be achieved by posttranslational protein modifications. One of the most studied modifications has been conjugation to ubiquitin, which mainly targets substrate proteins for degradation by the 26 S proteasome. Recently, SUMO/sentrin, a ubiquitin-like protein has been characterized. This evolutionary conserved protein is conjugated to specific proteins in a way similar, but not identical, to ubiquitin and seems also to be involved in the regulation of protein localization or function. An increasing number of SUMO/sentrin substrates are currently described. We focus here on three major substrates of modification by SUMO: RanGAP1, PML, and I(kappa)B(alpha) proteins. These different examples illustrate how SUMO conjugation may be involved in the control of the level of critical proteins within the cell or in the modulation of subcellular localization and nucleocytoplasmic trafficking.Key words: protein modification, NF-(kappa)B, I(kappa)B, protein transport, nucleus, RanGAP1, PML.



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