1
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Song XJ, Zhou HY, Sun YY, Huang HC. Phosphorylation and Glycosylation of Amyloid-β Protein Precursor: The Relationship to Trafficking and Cleavage in Alzheimer's Disease. J Alzheimers Dis 2021; 84:937-957. [PMID: 34602469 DOI: 10.3233/jad-210337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder in the central nervous system, and this disease is characterized by extracellular senile plaques and intracellular neurofibrillary tangles. Amyloid-β (Aβ) peptide is the main constituent of senile plaques, and this peptide is derived from the amyloid-β protein precursor (AβPP) through the successive cleaving by β-site AβPP-cleavage enzyme 1 (BACE1) and γ-secretase. AβPP undergoes the progress of post-translational modifications, such as phosphorylation and glycosylation, which might affect the trafficking and the cleavage of AβPP. In the recent years, about 10 phosphorylation sites of AβPP were identified, and they play complex roles in glycosylation modification and cleavage of AβPP. In this article, we introduced the transport and the cleavage pathways of AβPP, then summarized the phosphorylation and glycosylation sites of AβPP, and further discussed the links and relationship between phosphorylation and glycosylation on the pathways of AβPP trafficking and cleavage in order to provide theoretical basis for AD research.
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Affiliation(s)
- Xi-Jun Song
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - He-Yan Zhou
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Yu-Ying Sun
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Han-Chang Huang
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
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2
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Naka Y, Okada T, Nakagawa T, Kobayashi E, Kawasaki Y, Tanaka Y, Tawa H, Hirata Y, Kawakami K, Kakimoto K, Inoue T, Takeuchi T, Fukunishi S, Hirose Y, Uchiyama K, Asahi M, Higuchi K. Enhancement of O-linked N-acetylglucosamine modification promotes metastasis in patients with colorectal cancer and concurrent type 2 diabetes mellitus. Oncol Lett 2020; 20:1171-1178. [PMID: 32724357 PMCID: PMC7378307 DOI: 10.3892/ol.2020.11665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/16/2020] [Indexed: 12/29/2022] Open
Abstract
Reversible post-translational modification of serine and threonine residues by O-linked N-acetylglucosamine (O-GlcNAc), termed O-GlcNAcylation has been indicated to regulate the activities of a number of different proteins. Augmented O-GlcNAcylation contributes to the etiologies of type 2 diabetes mellitus (T2DM) and cancer. Moreover, diabetic conditions increase the risk of colorectal cancer. However, the effect of O-GlcNAcylation in patients with colorectal cancer and concurrent T2DM has not been elucidated. The current study evaluated the level of O-GlcNAcylation in patients with colorectal cancer with or without T2DM. Notably, O-GlcNAcylation levels were significantly higher in tissues from patients with T2DM compared with those in patients without T2DM, and higher in cancer tissues compared with corresponding adjacent tissues. O-GlcNAcylation and cancer stage were more strongly correlated in cancer tissues from patients with T2DM compared with those from patients without T2DM. Additionally, distant metastasis was significantly correlated with O-GlcNAcylation in cancer tissues from patients with T2DM. β-catenin levels in colorectal cancer tissues were the highest in patients with advanced-stage cancer and concurrent T2DM. In SW480 human colon cancer cells, thiamet G (TMG) treatment and OGA silencing, which increased O-GlcNAcylation, significantly increased β-catenin and SNAIL in high-glucose, but not during normal-glucose conditions. These data suggest that O-GlcNAcylation is closely associated with distant metastasis, most likely through upregulation of the β-catenin/SNAIL signaling pathway in colorectal cancer patients with T2DM.
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Affiliation(s)
- Yutaka Naka
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan.,Internal Medicine, Katsuragi Hospital, Kishiwada, Osaka 596-0825, Japan
| | - Toshihiko Okada
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan.,Internal Medicine, Katsuragi Hospital, Kishiwada, Osaka 596-0825, Japan
| | - Takatoshi Nakagawa
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Eiko Kobayashi
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Yuka Kawasaki
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan.,Internal Medicine, Katsuragi Hospital, Kishiwada, Osaka 596-0825, Japan
| | - Yasuyoshi Tanaka
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Hideki Tawa
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Yuki Hirata
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Ken Kawakami
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Kazuki Kakimoto
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Takuya Inoue
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Toshihisa Takeuchi
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Shinya Fukunishi
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Yoshinobu Hirose
- Department of Pathology, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Kazuhisa Uchiyama
- Department of General and Gastroenterological Surgery, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Michio Asahi
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Kazuhide Higuchi
- Second Department of Internal Medicine, Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
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3
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Increased O-GlcNAcylation rapidly decreases GABA AR currents in hippocampus but depresses neuronal output. Sci Rep 2020; 10:7494. [PMID: 32366857 PMCID: PMC7198489 DOI: 10.1038/s41598-020-63188-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 03/02/2020] [Indexed: 02/08/2023] Open
Abstract
O-GlcNAcylation, a post-translational modification involving O-linkage of β-N-acetylglucosamine to Ser/Thr residues on target proteins, is increasingly recognized as a critical regulator of synaptic function. Enzymes that catalyze O-GlcNAcylation are found at both presynaptic and postsynaptic sites, and O-GlcNAcylated proteins localize to synaptosomes. An acute increase in O-GlcNAcylation can affect neuronal communication by inducing long-term depression (LTD) of excitatory transmission at hippocampal CA3-CA1 synapses, as well as suppressing hyperexcitable circuits in vitro and in vivo. Despite these findings, to date, no studies have directly examined how O-GlcNAcylation modulates the efficacy of inhibitory neurotransmission. Here we show an acute increase in O-GlcNAc dampens GABAergic currents onto principal cells in rodent hippocampus likely through a postsynaptic mechanism, and has a variable effect on the excitation/inhibition balance. The overall effect of increased O-GlcNAc is reduced synaptically-driven spike probability via synaptic depression and decreased intrinsic excitability. Our results position O-GlcNAcylation as a novel regulator of the overall excitation/inhibition balance and neuronal output.
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4
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Abstract
O-Linked N-acetyl glucosamine (O-GlcNAc) is a protein modification found on thousands of nuclear, cytosolic, and mitochondrial proteins. Many O-GlcNAc sites occur in proximity to protein sites that are likewise modified by phosphorylation. While several studies have uncovered crosstalk between these two signaling modifications on individual proteins and pathways, an understanding of the role of O-GlcNAc in regulating kinases, the enzymes that install the phosphate modification, is still emerging. Here we review recent methods to profile the O-GlcNAc modification on a global scale that have revealed more than 100 kinases are modified by O-GlcNAc and highlight existing studies about regulation of these kinases by O-GlcNAc. Continuing efforts to profile the O-GlcNAc proteome and understand the role of O-GlcNAc on kinases will reveal new mechanisms of regulation and potential avenues for manipulation of the signaling mechanisms at the intersection of O-GlcNAc and phosphorylation.
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Affiliation(s)
- Paul A. Schwein
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Christina M. Woo
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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5
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Park J, Lai MKP, Arumugam TV, Jo DG. O-GlcNAcylation as a Therapeutic Target for Alzheimer's Disease. Neuromolecular Med 2020; 22:171-193. [PMID: 31894464 DOI: 10.1007/s12017-019-08584-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 12/13/2019] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and the number of elderly patients suffering from AD has been steadily increasing. Despite worldwide efforts to cope with this disease, little progress has been achieved with regard to identification of effective therapeutics. Thus, active research focusing on identification of new therapeutic targets of AD is ongoing. Among the new targets, post-translational modifications which modify the properties of mature proteins have gained attention. O-GlcNAcylation, a type of PTM that attaches O-linked β-N-acetylglucosamine (O-GlcNAc) to a protein, is being sought as a new target to treat AD pathologies. O-GlcNAcylation has been known to modify the two important components of AD pathological hallmarks, amyloid precursor protein, and tau protein. In addition, elevating O-GlcNAcylation levels in AD animal models has been shown to be effective in alleviating AD-associated pathology. Although studies investigating the precise mechanism of reversal of AD pathologies by targeting O-GlcNAcylation are not yet complete, it is clearly important to examine O-GlcNAcylation regulation as a target of AD therapeutics. This review highlights the mechanisms of O-GlcNAcylation and its role as a potential therapeutic target under physiological and pathological AD conditions.
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Affiliation(s)
- Jinsu Park
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea
- Department of Health Science and Technology, Sungkyunkwan University, Seoul, 06351, Korea
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
| | - Thiruma V Arumugam
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea.
- Department of Physiology, Yong Loo Lin School Medicine, National University of Singapore, Singapore, 117593, Singapore.
- Department of Physiology, Anatomy & Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC, Australia.
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea.
- Department of Health Science and Technology, Sungkyunkwan University, Seoul, 06351, Korea.
- Biomedical Institute for Convergence, Sungkyunkwan University, Suwon, 16419, Korea.
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6
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Abstract
In the early 1980s, while using purified glycosyltransferases to probe glycan structures on surfaces of living cells in the murine immune system, we discovered a novel form of serine/threonine protein glycosylation (O-linked β-GlcNAc; O-GlcNAc) that occurs on thousands of proteins within the nucleus, cytoplasm, and mitochondria. Prior to this discovery, it was dogma that protein glycosylation was restricted to the luminal compartments of the secretory pathway and on extracellular domains of membrane and secretory proteins. Work in the last 3 decades from several laboratories has shown that O-GlcNAc cycling serves as a nutrient sensor to regulate signaling, transcription, mitochondrial activity, and cytoskeletal functions. O-GlcNAc also has extensive cross-talk with phosphorylation, not only at the same or proximal sites on polypeptides, but also by regulating each other's enzymes that catalyze cycling of the modifications. O-GlcNAc is generally not elongated or modified. It cycles on and off polypeptides in a time scale similar to phosphorylation, and both the enzyme that adds O-GlcNAc, the O-GlcNAc transferase (OGT), and the enzyme that removes O-GlcNAc, O-GlcNAcase (OGA), are highly conserved from C. elegans to humans. Both O-GlcNAc cycling enzymes are essential in mammals and plants. Due to O-GlcNAc's fundamental roles as a nutrient and stress sensor, it plays an important role in the etiologies of chronic diseases of aging, including diabetes, cancer, and neurodegenerative disease. This review will present an overview of our current understanding of O-GlcNAc's regulation, functions, and roles in chronic diseases of aging.
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Affiliation(s)
- Gerald W Hart
- From the Complex Carbohydrate Research Center and Biochemistry and Molecular Biology Department, University of Georgia, Athens, Georgia 30602
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7
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Zachara NE. Critical observations that shaped our understanding of the function(s) of intracellular glycosylation (O-GlcNAc). FEBS Lett 2018; 592:3950-3975. [PMID: 30414174 DOI: 10.1002/1873-3468.13286] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
Almost 100 years after the first descriptions of proteins conjugated to carbohydrates (mucins), several studies suggested that glycoproteins were not restricted to the serum, extracellular matrix, cell surface, or endomembrane system. In the 1980s, key data emerged demonstrating that intracellular proteins were modified by monosaccharides of O-linked β-N-acetylglucosamine (O-GlcNAc). Subsequently, this modification was identified on thousands of proteins that regulate cellular processes as diverse as protein aggregation, localization, post-translational modifications, activity, and interactions. In this Review, we will highlight critical discoveries that shaped our understanding of the molecular events underpinning the impact of O-GlcNAc on protein function, the role that O-GlcNAc plays in maintaining cellular homeostasis, and our understanding of the mechanisms that regulate O-GlcNAc-cycling.
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Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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8
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Abdallah FM, El Damaty HM, Kotb GF. Sporadic cases of lumpy skin disease among cattle in Sharkia province, Egypt: Genetic characterization of lumpy skin disease virus isolates and pathological findings. Vet World 2018; 11:1150-1158. [PMID: 30250377 PMCID: PMC6141277 DOI: 10.14202/vetworld.2018.1150-1158] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/12/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND AND AIM Lumpy skin disease (LSD) is a highly infectious viral disease upsetting cattle, caused by LSD virus (LSDV) within the family Poxviridae. Sporadic cases of LSD have been observed in cattle previously vaccinated with the Romanian sheep poxvirus (SPPV) vaccine during the summer of 2016 in Sharkia province, Egypt. The present study was undertaken to perform molecular characterization of LSDV strains which circulated in this period as well as investigate their phylogenetic relatedness with published reference capripoxvirus genome sequences. MATERIALS AND METHODS A total of 82 skin nodules, as well as 5 lymph nodes, were collected from suspect LSD cases, and the virus was isolated in embryonated chicken eggs (ECEs). LSD was confirmed by polymerase chain reactions amplification of the partial and full-length sequences of the attachment and G-protein-coupled chemokine receptor (GPCR) genes, respectively, as well as a histopathological examination of the lesions. Molecular characterization of the LSDV isolates was conducted by sequencing the GPCR gene. RESULTS Characteristic skin nodules that covered the whole intact skin, as well as lymphadenopathy, were significant clinical signs in all suspected cases. LSDV isolation in ECEs revealed the characteristic focal white pock lesions dispersed on the chorioallantoic membranes. Histopathologic examination showed characteristic eosinophilic intracytoplasmic inclusion bodies within inflammatory cell infiltration. Phylogenetic analysis revealed that the LSDV isolates were clustered together with other African and European LSDV strains. In addition, the LSDV isolates have a unique signature of LSDVs (A11, T12, T34, S99, and P199). CONCLUSION LSDV infections have been detected in cattle previously vaccinated with Romanian SPPV vaccine during the summer of 2016 and making the evaluation of vaccine efficacy under field conditions necessary.
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Affiliation(s)
- Fatma M. Abdallah
- Department of Virology, Faculty of Veterinary Medicine, Zagazig University, 44511-Zagazig, Sharkia Province, Egypt
| | - Hend M. El Damaty
- Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, 44511-Zagazig, Sharkia Province, Egypt
| | - Gamilat F. Kotb
- Department of Virology, Faculty of Veterinary Medicine, Zagazig University, 44511-Zagazig, Sharkia Province, Egypt
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9
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Lagerlöf O. O-GlcNAc cycling in the developing, adult and geriatric brain. J Bioenerg Biomembr 2018; 50:241-261. [PMID: 29790000 PMCID: PMC5984647 DOI: 10.1007/s10863-018-9760-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Hundreds of proteins in the nervous system are modified by the monosaccharide O-GlcNAc. A single protein is often O-GlcNAcylated on several amino acids and the modification of a single site can play a crucial role for the function of the protein. Despite its complexity, only two enzymes add and remove O-GlcNAc from proteins, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Global and local regulation of these enzymes make it possible for O-GlcNAc to coordinate multiple cellular functions at the same time as regulating specific pathways independently from each other. If O-GlcNAcylation is disrupted, metabolic disorder or intellectual disability may ensue, depending on what neurons are affected. O-GlcNAc's promise as a clinical target for developing drugs against neurodegenerative diseases has been recognized for many years. Recent literature puts O-GlcNAc in the forefront among mechanisms that can help us better understand how neuronal circuits integrate diverse incoming stimuli such as fluctuations in nutrient supply, metabolic hormones, neuronal activity and cellular stress. Here the functions of O-GlcNAc in the nervous system are reviewed.
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Affiliation(s)
- Olof Lagerlöf
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
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10
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Cork GK, Thompson J, Slawson C. Real Talk: The Inter-play Between the mTOR, AMPK, and Hexosamine Biosynthetic Pathways in Cell Signaling. Front Endocrinol (Lausanne) 2018; 9:522. [PMID: 30237786 PMCID: PMC6136272 DOI: 10.3389/fendo.2018.00522] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/21/2018] [Indexed: 12/22/2022] Open
Abstract
O-linked N-acetylglucosamine, better known as O-GlcNAc, is a sugar post-translational modification participating in a diverse range of cell functions. Disruptions in the cycling of O-GlcNAc mediated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively, is a driving force for aberrant cell signaling in disease pathologies, such as diabetes, obesity, Alzheimer's disease, and cancer. Production of UDP-GlcNAc, the metabolic substrate for OGT, by the Hexosamine Biosynthetic Pathway (HBP) is controlled by the input of amino acids, fats, and nucleic acids, making O-GlcNAc a key nutrient-sensor for fluctuations in these macromolecules. The mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) pathways also participate in nutrient-sensing as a means of controlling cell activity and are significant factors in a variety of pathologies. Research into the individual nutrient-sensitivities of the HBP, AMPK, and mTOR pathways has revealed a complex regulatory dynamic, where their unique responses to macromolecule levels coordinate cell behavior. Importantly, cross-talk between these pathways fine-tunes the cellular response to nutrients. Strong evidence demonstrates that AMPK negatively regulates the mTOR pathway, but O-GlcNAcylation of AMPK lowers enzymatic activity and promotes growth. On the other hand, AMPK can phosphorylate OGT leading to changes in OGT function. Complex sets of interactions between the HBP, AMPK, and mTOR pathways integrate nutritional signals to respond to changes in the environment. In particular, examining these relationships using systems biology approaches might prove a useful method of exploring the complex nature of cell signaling. Overall, understanding the complex interactions of these nutrient pathways will provide novel mechanistic information into how nutrients influence health and disease.
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Affiliation(s)
- Gentry K. Cork
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Pathology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Jeffrey Thompson
- Department of Biostatistics, University of Kansas Medical Center, Kansas City, KS, United States
| | - Chad Slawson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States
- *Correspondence: Chad Slawson
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11
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Hwang H, Rhim H. Functional significance of O-GlcNAc modification in regulating neuronal properties. Pharmacol Res 2017; 129:295-307. [PMID: 29223644 DOI: 10.1016/j.phrs.2017.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 11/17/2017] [Accepted: 12/04/2017] [Indexed: 12/22/2022]
Abstract
Post-translational modifications (PTMs) covalently modify proteins and diversify protein functions. Along with protein phosphorylation, another common PTM is the addition of O-linked β-N-acetylglucosamine (O-GlcNAc) to serine and/or threonine residues. O-GlcNAc modification is similar to phosphorylation in that it occurs to serine and threonine residues and cycles on and off with a similar time scale. However, a striking difference is that the addition and removal of the O-GlcNAc moiety on all substrates are mediated by the two enzymes regardless of proteins, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. O-GlcNAcylation can interact or potentially compete with phosphorylation on serine and threonine residues, and thus serves as an important molecular mechanism to modulate protein functions and activation. However, it has been challenging to address the role of O-GlcNAc modification in regulating protein functions at the molecular level due to the lack of convenient tools to determine the sites and degrees of O-GlcNAcylation. Studies in this field have only begun to expand significantly thanks to the recent advances in detection and manipulation methods such as quantitative proteomics and highly selective small-molecule inhibitors for OGT and OGA. Interestingly, multiple brain regions, especially hippocampus, express high levels of both OGT and OGA, and a number of neuron-specific proteins have been reported to undergo O-GlcNAcylation. This review aims to discuss the recent updates concerning the impacts of O-GlcNAc modification on neuronal functions at multiple levels ranging from intrinsic neuronal properties to synaptic plasticity and animal behaviors.
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Affiliation(s)
- Hongik Hwang
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyewhon Rhim
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea.
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12
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Akan I, Olivier-Van Stichelen S, Bond MR, Hanover JA. Nutrient-driven O-GlcNAc in proteostasis and neurodegeneration. J Neurochem 2017; 144:7-34. [PMID: 29049853 DOI: 10.1111/jnc.14242] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/28/2017] [Accepted: 10/11/2017] [Indexed: 12/14/2022]
Abstract
Proteostasis is essential in the mammalian brain where post-mitotic cells must function for decades to maintain synaptic contacts and memory. The brain is dependent on glucose and other metabolites for proper function and is spared from metabolic deficits even during starvation. In this review, we outline how the nutrient-sensitive nucleocytoplasmic post-translational modification O-linked N-acetylglucosamine (O-GlcNAc) regulates protein homeostasis. The O-GlcNAc modification is highly abundant in the mammalian brain and has been linked to proteopathies, including neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. C. elegans, Drosophila, and mouse models harboring O-GlcNAc transferase- and O-GlcNAcase-knockout alleles have helped define the role O-GlcNAc plays in development as well as age-associated neurodegenerative disease. These enzymes add and remove the single monosaccharide from protein serine and threonine residues, respectively. Blocking O-GlcNAc cycling is detrimental to mammalian brain development and interferes with neurogenesis, neural migration, and proteostasis. Findings in C. elegans and Drosophila model systems indicate that the dynamic turnover of O-GlcNAc is critical for maintaining levels of key transcriptional regulators responsible for neurodevelopment cell fate decisions. In addition, pathways of autophagy and proteasomal degradation depend on a transcriptional network that is also reliant on O-GlcNAc cycling. Like the quality control system in the endoplasmic reticulum which uses a 'mannose timer' to monitor protein folding, we propose that cytoplasmic proteostasis relies on an 'O-GlcNAc timer' to help regulate the lifetime and fate of nuclear and cytoplasmic proteins. O-GlcNAc-dependent developmental alterations impact metabolism and growth of the developing mouse embryo and persist into adulthood. Brain-selective knockout mouse models will be an important tool for understanding the role of O-GlcNAc in the physiology of the brain and its susceptibility to neurodegenerative injury.
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Affiliation(s)
- Ilhan Akan
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Michelle R Bond
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - John A Hanover
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
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13
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Elucidating crosstalk mechanisms between phosphorylation and O-GlcNAcylation. Proc Natl Acad Sci U S A 2017; 114:E7255-E7261. [PMID: 28808029 DOI: 10.1073/pnas.1620529114] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins can be modified by multiple posttranslational modifications (PTMs), creating a PTM code that controls the function of proteins in space and time. Unraveling this complex PTM code is one of the great challenges in molecular biology. Here, using mass spectrometry-based assays, we focus on the most common PTMs-phosphorylation and O-GlcNAcylation-and investigate how they affect each other. We demonstrate two generic crosstalk mechanisms. First, we define a frequently occurring, very specific and stringent phosphorylation/O-GlcNAcylation interplay motif, (pSp/T)P(V/A/T)(gS/gT), whereby phosphorylation strongly inhibits O-GlcNAcylation. Strikingly, this stringent motif is substantially enriched in the human (phospho)proteome, allowing us to predict hundreds of putative O-GlcNAc transferase (OGT) substrates. A set of these we investigate further and show them to be decent substrates of OGT, exhibiting a negative feedback loop when phosphorylated at the P-3 site. Second, we demonstrate that reciprocal crosstalk does not occur at PX(S/T)P sites, i.e., at sites phosphorylated by proline-directed kinases, which represent 40% of all sites in the vertebrate phosphoproteomes.
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14
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The sweet side of the cell cycle. Biochem Soc Trans 2017; 45:313-322. [PMID: 28408472 DOI: 10.1042/bst20160145] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 02/07/2023]
Abstract
Cell division (mitosis) and gamete production (meiosis) are fundamental requirements for normal organismal development. The mammalian cell cycle is tightly regulated by different checkpoints ensuring complete and precise chromosomal segregation and duplication. In recent years, researchers have become increasingly interested in understanding how O-GlcNAc regulates the cell cycle. The O-GlcNAc post-translation modification is an O-glycosidic bond of a single β-N-acetylglucosamine sugar to serine/threonine residues of intracellular proteins. This modification is sensitive toward changes in nutrient levels in the cellular environment making O-GlcNAc a nutrient sensor capable of influencing cell growth and proliferation. Numerous studies have established that O-GlcNAcylation is essential in regulating mitosis and meiosis, while loss of O-GlcNAcylation is lethal in growing cells. Moreover, aberrant O-GlcNAcylation is linked with cancer and chromosomal segregation errors. In this review, we will discuss how O-GlcNAc controls different aspects of the cell cycle with a particular emphasis on mitosis and meiosis.
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15
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Memory and synaptic plasticity are impaired by dysregulated hippocampal O-GlcNAcylation. Sci Rep 2017; 7:44921. [PMID: 28368052 PMCID: PMC5377249 DOI: 10.1038/srep44921] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 02/14/2017] [Indexed: 12/15/2022] Open
Abstract
O-GlcNAcylated proteins are abundant in the brain and are associated with neuronal functions and neurodegenerative diseases. Although several studies have reported the effects of aberrant regulation of O-GlcNAcylation on brain function, the roles of O-GlcNAcylation in synaptic function remain unclear. To understand the effect of aberrant O-GlcNAcylation on the brain, we used Oga+/− mice which have an increased level of O-GlcNAcylation, and found that Oga+/− mice exhibited impaired spatial learning and memory. Consistent with this result, Oga+/− mice showed a defect in hippocampal synaptic plasticity. Oga heterozygosity causes impairment of both long-term potentiation and long-term depression due to dysregulation of AMPA receptor phosphorylation. These results demonstrate a role for hyper-O-GlcNAcylation in learning and memory.
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16
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Qin CX, Sleaby R, Davidoff AJ, Bell JR, De Blasio MJ, Delbridge LM, Chatham JC, Ritchie RH. Insights into the role of maladaptive hexosamine biosynthesis and O-GlcNAcylation in development of diabetic cardiac complications. Pharmacol Res 2016; 116:45-56. [PMID: 27988387 DOI: 10.1016/j.phrs.2016.12.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/28/2016] [Accepted: 12/13/2016] [Indexed: 12/21/2022]
Abstract
Diabetes mellitus significantly increases the risk of heart failure, independent of coronary artery disease. The mechanisms implicated in the development of diabetic heart disease, commonly termed diabetic cardiomyopathy, are complex, but much of the impact of diabetes on the heart can be attributed to impaired glucose handling. It has been shown that the maladaptive nutrient-sensing hexosamine biosynthesis pathway (HBP) contributes to diabetic complications in many non-cardiac tissues. Glucose metabolism by the HBP leads to enzymatically-regulated, O-linked attachment of a sugar moiety molecule, β-N-acetylglucosamine (O-GlcNAc), to proteins, affecting their biological activity (similar to phosphorylation). In normal physiology, transient activation of HBP/O-GlcNAc mechanisms is an adaptive, protective means to enhance cell survival; interventions that acutely suppress this pathway decrease tolerance to stress. Conversely, chronic dysregulation of HBP/O-GlcNAc mechanisms has been shown to be detrimental in certain pathological settings, including diabetes and cancer. Most of our understanding of the impact of sustained maladaptive HBP and O-GlcNAc protein modifications has been derived from adipose tissue, skeletal muscle and other non-cardiac tissues, as a contributing mechanism to insulin resistance and progression of diabetic complications. However, the long-term consequences of persistent activation of cardiac HBP and O-GlcNAc are not well-understood; therefore, the goal of this timely review is to highlight current understanding of the role of the HBP pathway in development of diabetic cardiomyopathy.
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Affiliation(s)
- Cheng Xue Qin
- Heart Failure Pharmacology, Baker IDI Heart & Diabetes Institute, Melbourne VIC 3004, Australia; Department of Pharmacology, University of Melbourne, VIC 3010, Australia
| | - Rochelle Sleaby
- Heart Failure Pharmacology, Baker IDI Heart & Diabetes Institute, Melbourne VIC 3004, Australia; Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Amy J Davidoff
- University of New England, Biddeford, ME, 04072, United States
| | - James R Bell
- Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Miles J De Blasio
- Heart Failure Pharmacology, Baker IDI Heart & Diabetes Institute, Melbourne VIC 3004, Australia; School of BioSciences, University of Melbourne, VIC 3010, Australia
| | | | - John C Chatham
- University of Alabama at Birmingham, Birmingham, AL, 35233, United States
| | - Rebecca H Ritchie
- Heart Failure Pharmacology, Baker IDI Heart & Diabetes Institute, Melbourne VIC 3004, Australia; Department of Pharmacology, University of Melbourne, VIC 3010, Australia; Department of Medicine, Monash University, Clayton 3800, VIC, Australia.
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17
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Lee A, Miller D, Henry R, Paruchuri VDP, O'Meally RN, Boronina T, Cole RN, Zachara NE. Combined Antibody/Lectin Enrichment Identifies Extensive Changes in the O-GlcNAc Sub-proteome upon Oxidative Stress. J Proteome Res 2016; 15:4318-4336. [PMID: 27669760 DOI: 10.1021/acs.jproteome.6b00369] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
O-Linked N-acetyl-β-d-glucosamine (O-GlcNAc) is a dynamic post-translational modification that modifies and regulates over 3000 nuclear, cytoplasmic, and mitochondrial proteins. Upon exposure to stress and injury, cells and tissues increase the O-GlcNAc modification, or O-GlcNAcylation, of numerous proteins promoting the cellular stress response and thus survival. The aim of this study was to identify proteins that are differentially O-GlcNAcylated upon acute oxidative stress (H2O2) to provide insight into the mechanisms by which O-GlcNAc promotes survival. We achieved this goal by employing Stable Isotope Labeling of Amino Acids in Cell Culture (SILAC) and a novel "G5-lectibody" immunoprecipitation strategy that combines four O-GlcNAc-specific antibodies (CTD110.6, RL2, HGAC39, and HGAC85) and the lectin WGA. Using the G5-lectibody column in combination with basic reversed phase chromatography and C18 RPLC-MS/MS, 990 proteins were identified and quantified. Hundreds of proteins that were identified demonstrated increased (>250) or decreased (>110) association with the G5-lectibody column upon oxidative stress, of which we validated the O-GlcNAcylation status of 24 proteins. Analysis of proteins with altered glycosylation suggests that stress-induced changes in O-GlcNAcylation cluster into pathways known to regulate the cell's response to injury and include protein folding, transcriptional regulation, epigenetics, and proteins involved in RNA biogenesis. Together, these data suggest that stress-induced O-GlcNAcylation regulates numerous and diverse cellular pathways to promote cell and tissue survival.
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Affiliation(s)
- Albert Lee
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Devin Miller
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Roger Henry
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Venkata D P Paruchuri
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Robert N O'Meally
- Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine , 733 North Broadway Street, Baltimore, Maryland 21205-2185, United States
| | - Tatiana Boronina
- Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine , 733 North Broadway Street, Baltimore, Maryland 21205-2185, United States
| | - Robert N Cole
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States.,Mass Spectrometry and Proteomics Facility, The Johns Hopkins University School of Medicine , 733 North Broadway Street, Baltimore, Maryland 21205-2185, United States
| | - Natasha E Zachara
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
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Burén S, Gomes AL, Teijeiro A, Fawal MA, Yilmaz M, Tummala KS, Perez M, Rodriguez-Justo M, Campos-Olivas R, Megías D, Djouder N. Regulation of OGT by URI in Response to Glucose Confers c-MYC-Dependent Survival Mechanisms. Cancer Cell 2016; 30:290-307. [PMID: 27505673 DOI: 10.1016/j.ccell.2016.06.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 08/01/2015] [Accepted: 06/29/2016] [Indexed: 01/09/2023]
Abstract
Cancer cells can adapt and survive under low nutrient conditions, but underlying mechanisms remain poorly explored. We demonstrate here that glucose maintains a functional complex between the co-chaperone URI, PP1γ, and OGT, the enzyme catalyzing O-GlcNAcylation. Glucose deprivation induces the activation of PKA, which phosphorylates URI at Ser-371, resulting in PP1γ release and URI-mediated OGT inhibition. Low OGT activity reduces O-GlcNAcylation and promotes c-MYC degradation to maintain cell survival. In the presence of glucose, PP1γ-bound URI increases OGT and c-MYC levels. Accordingly, mice expressing non-phosphorylatable URI (S371A) in hepatocytes exhibit high OGT activity and c-MYC stabilization, accelerating liver tumorigenesis in agreement with c-MYC oncogenic functions. Our work uncovers that URI-regulated OGT confers c-MYC-dependent survival functions in response to glucose fluctuations.
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Affiliation(s)
- Stefan Burén
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Ana L Gomes
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Ana Teijeiro
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Mohamad-Ali Fawal
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Mahmut Yilmaz
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Krishna S Tummala
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Manuel Perez
- Biotechnology Programme, Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Manuel Rodriguez-Justo
- Department of Research Pathology, Cancer Institute, University College London, London WC1E 6JJ, UK
| | - Ramón Campos-Olivas
- Structural Biology and Biocomputing Programme, Spectroscopy and Nuclear Magnetic Resonance Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Diego Megías
- Biotechnology Programme, Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Nabil Djouder
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain.
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19
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Hong-Brown LQ, Brown CR, Navaratnarajah M, Lang CH. Adamts1 mediates ethanol-induced alterations in collagen and elastin via a FoxO1-sestrin3-AMPK signaling cascade in myocytes. J Cell Biochem 2016; 116:91-101. [PMID: 25142777 DOI: 10.1002/jcb.24945] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 08/15/2014] [Indexed: 12/11/2022]
Abstract
A variety of stressors including alcohol (EtOH) are known to induce collagen production and fibrotic diseases. Matrix metalloproteinases (MMP) play an important role in regulating fibrosis, but little is known regarding the relationship between EtOH and MMPs. In addition, the signaling cascades involved in this process have not been elucidated. We have identified the MMP Adamts1 as a target of EtOH regulation. To characterize the function of Adamts1, we examined EtOH-induced alterations in collagen I and elastin protein levels in C2C12 myocytes. Incubation of myocytes with 100 mM EtOH decreased elastin and increased collagen content, respectively, and these changes were associated with increased O-GLcNAc modification of Adamts1. Conversely, silencing of Adamts1 by siRNA blocked the adverse effects of EtOH on collagen and elastin levels. Similar results were obtained after treatment with a pharmacological inhibitor of MMP. Changes in collagen were due, at least in part, to a decreased interaction of Adamts1 with its endogenous inhibitor TIMP3. The AMPK inhibitor compound C blocked the EtOH-induced stimulation of collagen and O-GLcNAc Adamts1 protein. Changes in AMPK appear linked to FoxO1, since inhibition of FoxO1 blocked the effects of EtOH on AMPK phosphorylation and O-GLcNAc levels. These FoxO-dependent modifications were associated with an upregulation of the FoxO1 transcription target sestrin 3, as well as increased binding of sestrin 3 with AMPK. Collectively, these data indicate that EtOH regulates the collagen I and elastin content in an Adamts1-dependent manner in myocytes. Furthermore, Adamts1 appears to be controlled by the FoxO1-sestrin 3-AMPK signaling cascade.
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Affiliation(s)
- Ly Q Hong-Brown
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, 17033, USA
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20
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K.M. Ip C, Yin J, K.S. Ng P, Lin SY, B. Mills G. Genomic-Glycosylation Aberrations in Tumor Initiation, Progression and Management. AIMS MEDICAL SCIENCE 2016. [DOI: 10.3934/medsci.2016.4.386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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21
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Systematic Analysis and Prediction of In Situ Cross Talk of O-GlcNAcylation and Phosphorylation. BIOMED RESEARCH INTERNATIONAL 2015; 2015:279823. [PMID: 26601103 PMCID: PMC4639640 DOI: 10.1155/2015/279823] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 10/01/2015] [Accepted: 10/04/2015] [Indexed: 01/17/2023]
Abstract
Reversible posttranslational modification (PTM) plays a very important role in biological process by changing properties of proteins. As many proteins are multiply modified by PTMs, cross talk of PTMs is becoming an intriguing topic and draws much attention. Currently, lots of evidences suggest that the PTMs work together to accomplish a specific biological function. However, both the general principles and underlying mechanism of PTM crosstalk are elusive. In this study, by using large-scale datasets we performed evolutionary conservation analysis, gene ontology enrichment, motif extraction of proteins with cross talk of O-GlcNAcylation and phosphorylation cooccurring on the same residue. We found that proteins with in situ O-GlcNAc/Phos cross talk were significantly enriched in some specific gene ontology terms and no obvious evolutionary pressure was observed. Moreover, 3 functional motifs associated with O-GlcNAc/Phos sites were extracted. We further used sequence features and GO features to predict O-GlcNAc/Phos cross talk sites based on phosphorylated sites and O-GlcNAcylated sites separately by the use of SVM model. The AUC of classifier based on phosphorylated sites is 0.896 and the other classifier based on GlcNAcylated sites is 0.843. Both classifiers achieved a relatively better performance compared with other existing methods.
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22
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Nagel AK, Ball LE. O-GlcNAc modification of the runt-related transcription factor 2 (Runx2) links osteogenesis and nutrient metabolism in bone marrow mesenchymal stem cells. Mol Cell Proteomics 2014; 13:3381-95. [PMID: 25187572 DOI: 10.1074/mcp.m114.040691] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Runx2 is the master switch controlling osteoblast differentiation and formation of the mineralized skeleton. The post-translational modification of Runx2 by phosphorylation, ubiquitinylation, and acetylation modulates its activity, stability, and interactions with transcriptional co-regulators and chromatin remodeling proteins downstream of osteogenic signals. Characterization of Runx2 by electron transfer dissociation tandem mass spectrometry revealed sites of O-linked N-acetylglucosamine (O-GlcNAc) modification, a nutrient-responsive post-translational modification that modulates the action of numerous transcriptional effectors. O-GlcNAc modification occurs in close proximity to phosphorylated residues and novel sites of arginine methylation within regions known to regulate Runx2 transactivation. An interaction between Runx2 and the O-GlcNAcylated, O-GlcNAc transferase enzyme was also detected. Pharmacological inhibition of O-GlcNAcase (OGA), the enzyme responsible for the removal of O-GlcNAc from Ser/Thr residues, enhanced basal (39.9%) and BMP2/7-induced (43.3%) Runx2 transcriptional activity in MC3T3-E1 pre-osteoblasts. In bone marrow-derived mesenchymal stem cells differentiated for 6 days in osteogenic media, inhibition of OGA resulted in elevated expression (24.3%) and activity (65.8%) of alkaline phosphatase (ALP) an early marker of bone formation and a transcriptional target of Runx2. Osteogenic differentiation of bone marrow-derived mesenchymal stem cells in the presence of BMP2/7 for 8 days culminated in decreased OGA activity (39.0%) and an increase in the abundance of O-GlcNAcylated Runx2, as compared with unstimulated cells. Furthermore, BMP2/7-induced ALP activity was enhanced by 35.6% in bone marrow-derived mesenchymal stem cells differentiated in the presence of the OGA inhibitor, demonstrating that direct or BMP2/7-induced inhibition of OGA is associated with increased ALP activity. Altogether, these findings link O-GlcNAc cycling to the Runx2-dependent regulation of the early ALP marker under osteoblast differentiation conditions.
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Affiliation(s)
- Alexis K Nagel
- From the ‡Department of Oral Health Sciences; Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina, 29425
| | - Lauren E Ball
- From the ‡Department of Oral Health Sciences; Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina, 29425
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23
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Lima VV, Lobato NS, Filgueira FP, Webb RC, Tostes RC, Giachini FR. Vascular O-GlcNAcylation augments reactivity to constrictor stimuli by prolonging phosphorylated levels of the myosin light chain. ACTA ACUST UNITED AC 2014; 47:826-33. [PMID: 25140811 PMCID: PMC4181217 DOI: 10.1590/1414-431x20144001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/09/2014] [Indexed: 01/31/2024]
Abstract
O-GlcNAcylation is a modification that alters the function of numerous proteins. We hypothesized that augmented O-GlcNAcylation levels enhance myosin light chain kinase (MLCK) and reduce myosin light chain phosphatase (MLCP) activity, leading to increased vascular contractile responsiveness. The vascular responses were measured by isometric force displacement. Thoracic aorta and vascular smooth muscle cells (VSMCs) from rats were incubated with vehicle or with PugNAc, which increases O-GlcNAcylation. In addition, we determined whether proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation. PugNAc enhanced phenylephrine (PE) responses in rat aortas (maximal effect, 14.2 ± 2 vs 7.9 ± 1 mN for vehicle, n=7). Treatment with an MLCP inhibitor (calyculin A) augmented vascular responses to PE (13.4 ± 2 mN) and abolished the differences in PE-response between the groups. The effect of PugNAc was not observed when vessels were preincubated with ML-9, an MLCK inhibitor (7.3 ± 2 vs 7.5 ± 2 mN for vehicle, n=5). Furthermore, our data showed that differences in the PE-induced contractile response between the groups were abolished by the activator of AMP-activated protein kinase (AICAR; 6.1 ± 2 vs 7.4 ± 2 mN for vehicle, n=5). PugNAc increased phosphorylation of myosin phosphatase target subunit 1 (MYPT-1) and protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), which are involved in RhoA/Rho-kinase-mediated inhibition of myosin phosphatase activity. PugNAc incubation produced a time-dependent increase in vascular phosphorylation of myosin light chain and decreased phosphorylation levels of AMP-activated protein kinase, which decreased the affinity of MLCK for Ca(2+)/calmodulin. Our data suggest that proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation, favoring vascular contraction.
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Affiliation(s)
- V V Lima
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT, Brasil
| | - N S Lobato
- Curso de Medicina, Setor de Fisiologia Humana, Universidade Federal de Goiás, Jataí, GO, Brasil
| | - F P Filgueira
- Curso de Medicina, Setor de Fisiologia Humana, Universidade Federal de Goiás, Jataí, GO, Brasil
| | - R C Webb
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - R C Tostes
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - F R Giachini
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT, Brasil
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24
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Slámová K, Kulik N, Fiala M, Krejzová-Hofmeisterová J, Ettrich R, Křen V. Expression, characterization and homology modeling of a novel eukaryotic GH84 β-N-acetylglucosaminidase from Penicillium chrysogenum. Protein Expr Purif 2014; 95:204-10. [DOI: 10.1016/j.pep.2014.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 01/09/2023]
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25
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Groves JA, Lee A, Yildirir G, Zachara NE. Dynamic O-GlcNAcylation and its roles in the cellular stress response and homeostasis. Cell Stress Chaperones 2013; 18:535-58. [PMID: 23620203 PMCID: PMC3745259 DOI: 10.1007/s12192-013-0426-y] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 12/15/2022] Open
Abstract
O-linked N-acetyl-β-D-glucosamine (O-GlcNAc) is a ubiquitous and dynamic post-translational modification known to modify over 3,000 nuclear, cytoplasmic, and mitochondrial eukaryotic proteins. Addition of O-GlcNAc to proteins is catalyzed by the O-GlcNAc transferase and is removed by a neutral-N-acetyl-β-glucosaminidase (O-GlcNAcase). O-GlcNAc is thought to regulate proteins in a manner analogous to protein phosphorylation, and the cycling of this carbohydrate modification regulates many cellular functions such as the cellular stress response. Diverse forms of cellular stress and tissue injury result in enhanced O-GlcNAc modification, or O-GlcNAcylation, of numerous intracellular proteins. Stress-induced O-GlcNAcylation appears to promote cell/tissue survival by regulating a multitude of biological processes including: the phosphoinositide 3-kinase/Akt pathway, heat shock protein expression, calcium homeostasis, levels of reactive oxygen species, ER stress, protein stability, mitochondrial dynamics, and inflammation. Here, we will discuss the regulation of these processes by O-GlcNAc and the impact of such regulation on survival in models of ischemia reperfusion injury and trauma hemorrhage. We will also discuss the misregulation of O-GlcNAc in diseases commonly associated with the stress response, namely Alzheimer's and Parkinson's diseases. Finally, we will highlight recent advancements in the tools and technologies used to study the O-GlcNAc modification.
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Affiliation(s)
- Jennifer A. Groves
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185 USA
| | - Albert Lee
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185 USA
| | - Gokben Yildirir
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185 USA
| | - Natasha E. Zachara
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185 USA
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26
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Dennis MD, Shenberger JS, Stanley BA, Kimball SR, Jefferson LS. Hyperglycemia mediates a shift from cap-dependent to cap-independent translation via a 4E-BP1-dependent mechanism. Diabetes 2013; 62:2204-14. [PMID: 23434932 PMCID: PMC3712054 DOI: 10.2337/db12-1453] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diabetes and its associated hyperglycemia induce multiple changes in liver function, yet we know little about the role played by translational control of gene expression in mediating the responses to these conditions. Here, we evaluate the hypothesis that hyperglycemia-induced O-GlcNAcylation of the translational regulatory protein 4E-BP1 alters hepatic gene expression through a process involving the selection of mRNA for translation. In both streptozotocin (STZ)-treated mice and cells in culture exposed to hyperglycemic conditions, expression of 4E-BP1 and its interaction with the mRNA cap-binding protein eIF4E were enhanced in conjunction with downregulation of cap-dependent and concomitant upregulation of cap-independent mRNA translation, as assessed by a bicistronic luciferase reporter assay. Phlorizin treatment of STZ-treated mice lowered blood glucose concentrations and reduced activity of the cap-independent reporter. Notably, the glucose-induced shift from cap-dependent to cap-independent mRNA translation did not occur in cells lacking 4E-BP1. The extensive nature of this shift in translational control of gene expression was revealed using pulsed stable isotope labeling by amino acids in cell culture to identify proteins that undergo altered rates of synthesis in response to hyperglycemia. Taken together, these data provide evidence for a novel mechanism whereby O-GlcNAcylation of 4E-BP1 mediates translational control of hepatic gene expression.
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Affiliation(s)
- Michael D. Dennis
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; the
| | - Jeffrey S. Shenberger
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and the
| | - Bruce A. Stanley
- Department of Microbiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Scot R. Kimball
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; the
- Corresponding author: Scot R. Kimball,
| | - Leonard S. Jefferson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; the
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27
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Lima VV, Rigsby CS, Hardy DM, Webb RC, Tostes RC. O-GlcNAcylation: a novel post-translational mechanism to alter vascular cellular signaling in health and disease: focus on hypertension. ACTA ACUST UNITED AC 2012; 3:374-87. [PMID: 20409980 DOI: 10.1016/j.jash.2009.09.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/26/2009] [Accepted: 09/28/2009] [Indexed: 12/21/2022]
Abstract
O-Linked attachment of beta-N-acetyl-glucosamine (O-GlcNAc) on serine and threonine residues of nuclear and cytoplasmic proteins is a highly dynamic posttranslational modification that plays a key role in signal transduction pathways. Preliminary data show that O-GlcNAcylation may represent a key regulatory mechanism in the vasculature, modulating contractile and relaxant responses. Proteins with an important role in vascular function, such as endothelial nitric oxide synthase, sarcoplasmic reticulum Ca(2+)-ATPase, protein kinase C, mitogen-activated protein kinases, and proteins involved in cytoskeleton regulation and microtubule assembly are targets for O-GlcNAcylation, indicating that this posttranslational modification may play an important role in vascular reactivity. Here, we will focus on a few specific pathways that contribute to vascular function and cardiovascular disease-associated vascular dysfunction, and the implications of their modification by O-GlcNAc. New chemical tools have been developed to detect and study O-GlcNAcylation, including inhibitors of O-GlcNAc enzymes, chemoenzymatic tagging methods, and quantitative proteomics strategies; these will also be briefly addressed. An exciting challenge in the future will be to better understand the cellular dynamics of this posttranslational modification, as well as the signaling pathways and mechanisms by which O-GlcNAc is regulated on specific proteins in the vasculature in health and disease.
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Affiliation(s)
- Victor V Lima
- Department of Physiology, Medical College of Georgia, Augusta, GA, USA; Department of Pharmacology, University of Sao Paulo, Sao Paulo, SP, Brazil
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Liu Y, Li X, Yu Y, Shi J, Liang Z, Run X, Li Y, Dai CL, Grundke-Iqbal I, Iqbal K, Liu F, Gong CX. Developmental regulation of protein O-GlcNAcylation, O-GlcNAc transferase, and O-GlcNAcase in mammalian brain. PLoS One 2012; 7:e43724. [PMID: 22928023 PMCID: PMC3425547 DOI: 10.1371/journal.pone.0043724] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/24/2012] [Indexed: 12/18/2022] Open
Abstract
O-GlcNAcylation is a common posttranslational modification of nucleocytoplasmic proteins by β-N-acetylglucosamine (GlcNAc). The dynamic addition and removal of O-GlcNAc groups to and from proteins are catalyzed by O-linked N-acetylglucosamine transferase (O-GlcNAc transferase, OGT) and β-N-acetylglucosaminidase (O-GlcNAcase, OGA), respectively. O-GlcNAcylation often modulates protein phosphorylation and regulates several cellular signaling and functions, especially in the brain. However, its developmental regulation is not well known. Here, we studied protein O-GlcNAcylation, OGT, and OGA in the rat brain at various ages from embryonic day 15 to the age of 2 years. We found a gradual decline of global protein O-GlcNAcylation during developmental stages and adulthood. This decline correlated positively to the total protein phosphorylation at serine residues, but not at threonine residues. The expression of OGT and OGA isoforms was regulated differently at various ages. Immunohistochemical studies revealed ubiquitous distribution of O-GlcNAcylation at all ages. Strong immunostaining of O-GlcNAc, OGT, and OGA was observed mostly in neuronal cell bodies and processes, further suggesting the role of O-GlcNAc modification of neuronal proteins in the brain. These studies provide fundamental knowledge of age-dependent protein modification by O-GlcNAc and will help guide future studies on the role of O-GlcNAcylation in the mammalian brain.
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Affiliation(s)
- Ying Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Xiaojing Li
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Yang Yu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Jianhua Shi
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Zhihou Liang
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Xiaoqin Run
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Yi Li
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Chun-ling Dai
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Inge Grundke-Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Fei Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Cheng-Xin Gong
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
- * E-mail:
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Trinidad JC, Barkan DT, Gulledge BF, Thalhammer A, Sali A, Schoepfer R, Burlingame AL. Global identification and characterization of both O-GlcNAcylation and phosphorylation at the murine synapse. Mol Cell Proteomics 2012; 11:215-29. [PMID: 22645316 DOI: 10.1074/mcp.o112.018366] [Citation(s) in RCA: 328] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
O-linked N-acetylglucosamine (O-GlcNAc) is a dynamic, reversible monosaccharide modifier of serine and threonine residues on intracellular protein domains. Crosstalk between O-GlcNAcylation and phosphorylation has been hypothesized. Here, we identified over 1750 and 16,500 sites of O-GlcNAcylation and phosphorylation from murine synaptosomes, respectively. In total, 135 (7%) of all O-GlcNAcylation sites were also found to be sites of phosphorylation. Although many proteins were extensively phosphorylated and minimally O-GlcNAcylated, proteins found to be extensively O-GlcNAcylated were almost always phosphorylated to a similar or greater extent, indicating the O-GlcNAcylation system is specifically targeting a subset of the proteome that is also phosphorylated. Both PTMs usually occur on disordered regions of protein structure, within which, the location of O-GlcNAcylation and phosphorylation is virtually random with respect to each other, suggesting that negative crosstalk at the structural level is not a common phenomenon. As a class, protein kinases are found to be more extensively O-GlcNAcylated than proteins in general, indicating the potential for crosstalk of phosphorylation with O-GlcNAcylation via regulation of enzymatic activity.
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Affiliation(s)
- Jonathan C Trinidad
- Department of Pharmaceutical Chemistry, UCSF, San Francisco, California 94158, USA
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30
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Dennis MD, Schrufer TL, Bronson SK, Kimball SR, Jefferson LS. Hyperglycemia-induced O-GlcNAcylation and truncation of 4E-BP1 protein in liver of a mouse model of type 1 diabetes. J Biol Chem 2011; 286:34286-97. [PMID: 21840999 DOI: 10.1074/jbc.m111.259457] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
4E-BP1 is a protein that, in its hypophosphorylated state, binds the mRNA cap-binding protein eIF4E and represses cap-dependent mRNA translation. By doing so, it plays a major role in the regulation of gene expression by controlling the overall rate of mRNA translation as well as the selection of mRNAs for translation. Phosphorylation of 4E-BP1 causes it to release eIF4E to function in mRNA translation. 4E-BP1 is also subject to covalent addition of N-acetylglucosamine to Ser or Thr residues (O-GlcNAcylation) as well as to truncation. In the truncated form, it is both resistant to phosphorylation and able to bind eIF4E with high affinity. In the present study, Ins2(Akita/+) diabetic mice were used to test the hypothesis that hyperglycemia and elevated flux of glucose through the hexosamine biosynthetic pathway lead to increased O-GlcNAcylation and truncation of 4E-BP1 and consequently decreased eIF4E function in the liver. The amounts of both full-length and truncated 4E-BP1 bound to eIF4E were significantly elevated in the liver of diabetic as compared with non-diabetic mice. In addition, O-GlcNAcylation of both the full-length and truncated proteins was elevated by 2.5- and 5-fold, respectively. Phlorizin treatment of diabetic mice lowered blood glucose concentrations and reduced the expression and O-GlcNAcylation of 4E-BP1. Additionally, when livers were perfused in the absence of insulin, 4E-BP1 phosphorylation in the livers of diabetic mice was normalized to the control value, yet O-GlcNAcylation and the association of 4E-BP1 with eIF4E remained elevated in the liver of diabetic mice. These findings provide insight into the pathogenesis of metabolic abnormalities associated with diabetes.
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Affiliation(s)
- Michael D Dennis
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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31
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Zachara NE, Molina H, Wong KY, Pandey A, Hart GW. The dynamic stress-induced "O-GlcNAc-ome" highlights functions for O-GlcNAc in regulating DNA damage/repair and other cellular pathways. Amino Acids 2011; 40:793-808. [PMID: 20676906 PMCID: PMC3329784 DOI: 10.1007/s00726-010-0695-z] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 07/09/2010] [Indexed: 12/21/2022]
Abstract
The modification of nuclear, mitochondrial, and cytoplasmic proteins by O-linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic and essential post-translational modification of metazoans. Numerous forms of cellular injury lead to elevated levels of O-GlcNAc in both in vivo and in vitro models, and elevation of O-GlcNAc levels before, or immediately after, the induction of cellular injury is protective in models of heat stress, oxidative stress, endoplasmic reticulum (ER) stress, hypoxia, ischemia reperfusion injury, and trauma hemorrhage. Together, these data suggest that O-GlcNAc is a regulator of the cellular stress response. However, the molecular mechanism(s) by which O-GlcNAc regulates protein function leading to enhanced cell survival have not been identified. In order to determine how O-GlcNAc modulates stress tolerance in these models we have used stable isotope labeling with amino acids in cell culture to determine the identity of proteins that undergo O-GlcNAcylation in response to heat shock. Numerous proteins with diverse functions were identified, including NF-90, RuvB-like 1 (Tip49α), RuvB-like 2 (Tip49β), and several COPII vesicle transport proteins. Many of these proteins bind double-stranded DNA-dependent protein kinase (PK), or double-stranded DNA breaks, suggesting a role for O-GlcNAc in regulating DNA damage signaling or repair. Supporting this hypothesis, we have shown that DNA-PK is O-GlcNAc modified in response to numerous forms of cellular stress.
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Affiliation(s)
- Natasha E Zachara
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205-2185, USA.
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32
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Lima VV, Giachini FR, Hardy DM, Webb RC, Tostes RC. O-GlcNAcylation: a novel pathway contributing to the effects of endothelin in the vasculature. Am J Physiol Regul Integr Comp Physiol 2010; 300:R236-50. [PMID: 21068200 DOI: 10.1152/ajpregu.00230.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Glycosylation with O-linked β-N-acetylglucosamine (O-GlcNAc) or O-GlcNAcylation on serine and threonine residues of nuclear and cytoplasmic proteins is a posttranslational modification that alters the function of numerous proteins important in vascular function, including kinases, phosphatases, transcription factors, and cytoskeletal proteins. O-GlcNAcylation is an innovative way to think about vascular signaling events both in physiological conditions and in disease states. This posttranslational modification interferes with vascular processes, mainly vascular reactivity, in conditions where endothelin-1 (ET-1) levels are augmented (e.g. salt-sensitive hypertension, ischemia/reperfusion, and stroke). ET-1 plays a crucial role in the vascular function of most organ systems, both in physiological and pathophysiological conditions. Recognition of ET-1 by the ET(A) and ET(B) receptors activates intracellular signaling pathways and cascades that result in rapid and long-term alterations in vascular activity and function. Components of these ET-1-activated signaling pathways (e.g., mitogen-activated protein kinases, protein kinase C, RhoA/Rho kinase) are also targets for O-GlcNAcylation. Recent experimental evidence suggests that ET-1 directly activates O-GlcNAcylation, and this posttranslational modification mediates important vascular effects of the peptide. This review focuses on ET-1-activated signaling pathways that can be modified by O-GlcNAcylation. A brief description of the O-GlcNAcylation biology is presented, and its role on vascular function is addressed. ET-1-induced O-GlcNAcylation and its implications for vascular function are then discussed. Finally, the interplay between O-GlcNAcylation and O-phosphorylation is addressed.
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Affiliation(s)
- Victor V Lima
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
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Kazemi Z, Chang H, Haserodt S, McKen C, Zachara NE. O-linked beta-N-acetylglucosamine (O-GlcNAc) regulates stress-induced heat shock protein expression in a GSK-3beta-dependent manner. J Biol Chem 2010; 285:39096-107. [PMID: 20926391 DOI: 10.1074/jbc.m110.131102] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To investigate the mechanisms by which O-linked β-N-acetylglucosamine modification of nucleocytoplasmic proteins (O-GlcNAc) confers stress tolerance to multiple forms of cellular injury, we explored the role(s) of O-GlcNAc in the regulation of heat shock protein (HSP) expression. Using a cell line in which deletion of the O-GlcNAc transferase (OGT; the enzyme that adds O-GlcNAc) can be induced by 4-hydroxytamoxifen, we screened the expression of 84 HSPs using quantitative reverse transcriptase PCR. In OGT null cells the stress-induced expression of 18 molecular chaperones, including HSP72, were reduced. GSK-3β promotes apoptosis through numerous pathways, including phosphorylation of heat shock factor 1 (HSF1) at Ser(303) (Ser(P)(303) HSF1), which inactivates HSF1 and inhibits HSP expression. In OGT null cells we observed increased Ser(P)(303) HSF1; conversely, in cells in which O-GlcNAc levels had been elevated, reduced Ser(P)(303) HSF1 was detected. These data, combined with those showing that inhibition of GSK-3β in OGT null cells recovers HSP72 expression, suggests that O-GlcNAc regulates the activity of GSK-3β. In OGT null cells, stress-induced inactivation of GSK-3β by phosphorylation at Ser(9) was ablated providing a molecular basis for these findings. Together, these data suggest that stress-induced GlcNAcylation increases HSP expression through inhibition of GSK-3β.
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Affiliation(s)
- Zahra Kazemi
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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34
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Zeidan Q, Hart GW. The intersections between O-GlcNAcylation and phosphorylation: implications for multiple signaling pathways. J Cell Sci 2010; 123:13-22. [PMID: 20016062 DOI: 10.1242/jcs.053678] [Citation(s) in RCA: 247] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A paradigm-changing discovery in biology came about when it was found that nuclear and cytosolic proteins could be dynamically glycosylated with a single O-linked beta-N-acetylglucosamine (O-GlcNAc) moiety. O-GlcNAcylation is akin to phosphorylation: it occurs on serine and/or threonine side chains of proteins, and cycles rapidly upon cellular activation. O-GlcNAc and phosphate show a complex interplay: they can either competitively occupy a single site or proximal sites, or noncompetitively occupy different sites on a substrate. Phosphorylation regulates O-GlcNAc-cycling enzymes and, conversely, O-GlcNAcylation controls phosphate-cycling enzymes. Such crosstalk is evident in all compartments of the cell, a finding that is congruent with the fundamental role of O-GlcNAc in regulating nutrient- and stress-induced signal transduction. O-GlcNAc transferase is recruited to the plasma membrane in response to insulin and is targeted to substrates by forming transient holoenzyme complexes that have different specificities. Cytosolic O-GlcNAcylation is important for the proper transduction of signaling cascades such as the NFkappaB pathway, whereas nuclear O-GlcNAc is crucial for regulating the activity of numerous transcription factors. This Commentary focuses on recent findings supporting an emerging concept that continuous crosstalk between phosphorylation and O-GlcNAcylation is essential for the control of vital cellular processes and for understanding the mechanisms that underlie certain neuropathologies.
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Din N, Ahmad I, Ul Haq I, Elahi S, Hoessli DC, Shakoori AR. The function of GluR1 and GluR2 in cerebellar and hippocampal LTP and LTD is regulated by interplay of phosphorylation and O-GlcNAc modification. J Cell Biochem 2010; 109:585-97. [PMID: 20052678 DOI: 10.1002/jcb.22436] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are the current models of synaptic plasticity and widely believed to explain how different kinds of memory are stored in different brain regions. Induction of LTP and LTD in different regions of brain undoubtedly involve trafficking of AMPA receptor to and from synapses. Hippocampal LTP involves phosphorylation of GluR1 subunit of AMPA receptor and its delivery to synapse whereas; LTD is the result of dephosphorylation and endocytosis of GluR1 containing AMPA receptor. Conversely the cerebellar LTD is maintained by the phosphorylation of GluR2 which promotes receptor endocytosis while dephosphorylation of GluR2 triggers receptor expression at the cell surface and results in LTP. The interplay of phosphorylation and O-GlcNAc modification is known as functional switch in many neuronal proteins. In this study it is hypothesized that a same phenomenon underlies as LTD and LTP switching, by predicting the potential of different Ser/Thr residues for phosphorylation, O-GlcNAc modification and their possible interplay. We suggest the involvement of O-GlcNAc modification of dephosphorylated GluR1 in maintaining the hippocampal LTD and that of dephosphorylated GluR2 in cerebral LTP.
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Affiliation(s)
- Nasirud Din
- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan.
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36
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Site-specific interplay between O-GlcNAcylation and phosphorylation in cellular regulation. FEBS Lett 2010; 584:2526-38. [DOI: 10.1016/j.febslet.2010.04.044] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 04/15/2010] [Indexed: 11/17/2022]
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37
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Kaleem A, Ahmad I, Walker-Nasir E, Hoessli DC, Shakoori AR. Effect on the Ras/Raf signaling pathway of post-translational modifications of neurofibromin: in silico study of protein modification responsible for regulatory pathways. J Cell Biochem 2010; 108:816-24. [PMID: 19718661 DOI: 10.1002/jcb.22301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mapping and chemical characterization of post-translational modifications (PTMs) in proteins are critical to understand the regulatory mechanisms involving modified proteins and their role in disease. Neurofibromatosis type 1 (NF-1) is an autosomal dominantly inherited disorder, where NF1 mutations usually result in a reduced level of the tumor suppressor protein, neurofibromin (NF). NF is a multifunctional cytoplasmic protein that regulates microtubule dynamics and participates in several signaling pathways, particularly the RAS signaling pathway. NF is a Ras GTPase-activating protein (GAP) that prevents oncogenesis by converting GTP-Ras to GDP-Ras. This function of NF is regulated by phosphorylation. Interplay of phosphorylation with O-GlcNAc modification on the same or vicinal Ser/Thr residues, the Yin Yang sites, is well known in cytoplasmic and nuclear proteins. The dynamic aspects of PTMs and their interplay being difficult to follow in vivo, we undertook this in silico work to predict and define the possible role of Yin Yang sites in NF-1. Interplay of phosphorylation and O-GlcNAc modification is proposed as a mechanism controlling the Ras signaling pathway.
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Affiliation(s)
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- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan.
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38
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Butkinaree C, Park K, Hart GW. O-linked beta-N-acetylglucosamine (O-GlcNAc): Extensive crosstalk with phosphorylation to regulate signaling and transcription in response to nutrients and stress. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1800:96-106. [PMID: 19647786 PMCID: PMC2815129 DOI: 10.1016/j.bbagen.2009.07.018] [Citation(s) in RCA: 339] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 07/14/2009] [Accepted: 07/18/2009] [Indexed: 02/03/2023]
Abstract
BACKGROUND Since its discovery in the early 1980s, O-linked-beta-N-acetylglucosamine (O-GlcNAc), a single sugar modification on the hydroxyl group of serine or threonine residues, has changed our views of protein glycosylation. While other forms of protein glycosylation modify proteins on the cell surface or within luminal compartments of the secretory machinery, O-GlcNAc modifies myriad nucleocytoplasmic proteins. GlcNAcylated proteins are involved in transcription, ubiquitination, cell cycle, and stress responses. GlcNAcylation is similar to protein phosphorylation in terms of stoichiometry, localization and cycling. To date, only two enzymes are known to regulate GlcNAcylation in mammals: O-GlcNAc transferase (OGT), which catalyzes the addition of O-GlcNAc, and beta-N-acetylglucosaminidase (O-GlcNAcase), a neutral hexosaminidase responsible for O-GlcNAc removal. OGT and O-GlcNAcase are regulated by RNA splicing, by nutrients, and by post-translational modifications. Their specificities are controlled by many transiently associated targeting subunits. As methods for detecting O-GlcNAc have improved our understanding of O-GlcNAc's functions has grown rapidly. SCOPE OF REVIEW In this review, the functions of GlcNAcylation in regulating cellular processes, its extensive crosstalk with protein phosphorylation, and regulation of OGT and O-GlcNAcase will be explored. MAJOR CONCLUSIONS GlcNAcylation rivals phosphorylation in terms of its abundance, protein distribution and its cycling on and off of proteins. GlcNAcylation has extensive crosstalk with phosphorylation to regulate signaling, transcription and the cytoskeleton in response to nutrients and stress. GENERAL SIGNIFICANCE Abnormal crosstalk between GlcNAcylation and phosphorylation underlies dysregulation in diabetes, including glucose toxicity, and defective GlcNAcylation is involved in neurodegenerative disease and cancer and most recently in AIDS.
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Affiliation(s)
- Chutikarn Butkinaree
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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39
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Yanagisawa M, Yu RK. O-linked beta-N-acetylglucosaminylation in mouse embryonic neural precursor cells. J Neurosci Res 2010; 87:3535-45. [PMID: 19598243 DOI: 10.1002/jnr.22170] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In neural stem cells (NSCs), glycoconjugates and carbohydrate antigens are known not only to serve as excellent cell surface biomarkers for cellular differentiation and development but also to play important functional roles in determining cell fate. O-linked beta-N-acetylglucosamine (O-GlcNAc), which modifies nuclear and cytoplasmic proteins on the serine and threonine residues, is also expected to play an important regulatory role. It is not known, however, whether O-GlcNAc is expressed in NSCs or what the function of this expression is. In this study, we evaluated the patterns and possible functions of O-GlcNAcylation in mouse embryonic neuroepithelial cells (NECs), which are known to be rich in NSCs. We confirmed the expression of O-GlcNAc transferase, O-GlcNAcase, and several O-GlcNAcylated proteins in NECs. Treatment of NECs with O-GlcNAcase inhibitors, PUGNAc and streptozotocin, induced robust accumulation of O-GlcNAc in NECs and reduction of number of NECs. In O-GlcNAcase inhibitor-treated NECs, the Ras-mitogen-activated protein kinase pathway and the phosphatidylinositol 3-kinase-Akt pathway, important for proliferation and survival, respectively, were intact, but caspase-3, an executioner for cell death, was activated. These results suggest the possibility that O-GlcNAc is involved in cell death signaling in NECs. Furthermore, in NECs, we identified an O-GlcNAc-modified protein, Sp1 transcription factor. Our study is the first to evaluate expression and functions of O-GlcNAc in NECs.
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Affiliation(s)
- Makoto Yanagisawa
- Institute of Molecular Medicine and Genetics and Institute of Neuroscience, Medical College of Georgia, Augusta, Georgia 30912, USA
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40
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Macauley MS, Vocadlo DJ. Increasing O-GlcNAc levels: An overview of small-molecule inhibitors of O-GlcNAcase. Biochim Biophys Acta Gen Subj 2009; 1800:107-21. [PMID: 19664691 DOI: 10.1016/j.bbagen.2009.07.028] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 07/17/2009] [Accepted: 07/28/2009] [Indexed: 11/25/2022]
Abstract
The O-GlcNAc modification is found on many nucleocytoplasmic proteins. The dynamic nature of O-GlcNAc, which in some ways is reminiscent of phosphorylation, has enabled investigators to modulate the stoichiometry of O-GlcNAc on proteins in order to study its function. Although several genetic and pharmacological methods for manipulating O-GlcNAc levels have been described, one of the most direct approaches of increasing global O-GlcNAc levels is by using small-molecule inhibitors of O-GlcNAcase (OGA). As the interest in increasing O-GlcNAc levels has grown, so too has the number of OGA inhibitors. This review provides an overview of the available methods of increasing O-GlcNAc levels, with a special emphasis on inhibition of OGA by small molecules. Known inhibitors of OGA are discussed with particular attention on those most suitable for cell-based biological studies. Several examples in which OGA inhibitors have been used to study the functional role of the O-GlcNAc modification in biological systems are discussed, highlighting the pros and cons of different inhibitors.
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Affiliation(s)
- Matthew S Macauley
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
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Francisco H, Kollins K, Varghis N, Vocadlo D, Vosseller K, Gallo G. O-GLcNAc post-translational modifications regulate the entry of neurons into an axon branching program. Dev Neurobiol 2009; 69:162-73. [PMID: 19086029 PMCID: PMC2747243 DOI: 10.1002/dneu.20695] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many neuronal cytosolic and nuclear proteins are post-translationally modified by the reversible addition of O-linked N-acetylglucosamine (O-GlcNAc) on serines and threonines. The cellular functions of O-GlcNAc modifications in neuronal development are not known. We report that O-GlcNAc-modified proteins are distributed nonuniformly throughout cultured primary chicken forebrain neurons, with intense immunostaining of the cell body, punctuate immunostaining in axons and all processes, and localization in filopodia/lamellipodia. Overexpression of O-GlcNAcase, the enzyme that removes O-GlcNAc from proteins, increased the percentage of neurons exhibiting axon branching without altering the frequency of axon branches on a per neuron basis and increased the numbers of axonal filopodia. Conversely, pharmacologically increasing O-GlcNAc levels on proteins through specific inhibition of O-GlcNAcase with the inhibitor 9d decreased the numbers of axonal filopodia, but had no effect on axon length or branching. Treatment with an alternative O-GlcNAcase inhibitor, PUGNAc, similarly decreased the number of axonal filopodia. Furthermore, axon branching induced by the adenylyl cyclase activator forskolin was suppressed by pharmacological inhibition of O-GlcNAcase. Western analysis revealed that O-GlcNAc levels regulate the phosphorylation of some PKA substrates in response to forskolin. These data provide the first evidence of O-GlcNAc modification-specific influences in neuronal development in primary culture, and indicate specific roles for O-GlcNAc in the regulation of axon morphology. © 2008 Wiley Periodicals, Inc. Develop Neurobiol 69: 162–173, 2009
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Affiliation(s)
- Herb Francisco
- Department of Neurobiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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Tallent MK, Varghis N, Skorobogatko Y, Hernandez-Cuebas L, Whelan K, Vocadlo DJ, Vosseller K. In vivo modulation of O-GlcNAc levels regulates hippocampal synaptic plasticity through interplay with phosphorylation. J Biol Chem 2008; 284:174-181. [PMID: 19004831 DOI: 10.1074/jbc.m807431200] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-Linked N-acetylglucosamine (O-GlcNAc) is a cytosolic and nuclear carbohydrate post-translational modification most abundant in brain. We recently reported uniquely extensive O-GlcNAc modification of proteins that function in synaptic vesicle release and post-synaptic signal transduction. Here we examined potential roles for O-GlcNAc in mouse hippocampal synaptic transmission and plasticity. O-GlcNAc modifications and the enzyme catalyzing their addition (O-GlcNAc transferase) were enriched in hippocampal synaptosomes. Pharmacological elevation or reduction of O-GlcNAc levels had no effect on Schaffer collateral CA1 basal hippocampal synaptic transmission. However, in vivo elevation of O-GlcNAc levels enhanced long term potentiation (LTP), an electrophysiological correlate to some forms of learning/memory. Reciprocally, pharmacological reduction of O-GlcNAc levels blocked LTP. Additionally, elevated O-GlcNAc led to reduced paired-pulse facilitation, a form of short term plasticity attributed to presynaptic mechanisms. Synapsin I and II are presynaptic proteins that increase synaptic vesicle availability for release when phosphorylated, thus contributing to hippocampal synaptic plasticity. Synapsins are among the most extensively O-GlcNAc-modified proteins known. Elevating O-GlcNAc levels increased phosphorylation of Synapsin I/II at serine 9 (cAMP-dependent protein kinase substrate site), serine 62/67 (Erk 1/2 (MAPK 1/2) substrate site), and serine 603 (calmodulin kinase II site). Activation-specific phosphorylation events on Erk 1/2 and calmodulin kinase II, two proteins required for CA1 hippocampal LTP establishment, were increased in response to elevation of O-GlcNAc levels. Thus, O-GlcNAc is a novel regulatory signaling component of excitatory synapses, with specific roles in synaptic plasticity that involve interplay with phosphorylation.
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Affiliation(s)
- Melanie K Tallent
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Neal Varghis
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Yuliya Skorobogatko
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Lisa Hernandez-Cuebas
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Kelly Whelan
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - David J Vocadlo
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Keith Vosseller
- Department of Biochemistry and Molecular Biology and Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
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Wang Z, Gucek M, Hart GW. Cross-talk between GlcNAcylation and phosphorylation: site-specific phosphorylation dynamics in response to globally elevated O-GlcNAc. Proc Natl Acad Sci U S A 2008; 105:13793-8. [PMID: 18779572 PMCID: PMC2544533 DOI: 10.1073/pnas.0806216105] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2008] [Indexed: 11/18/2022] Open
Abstract
Protein GlcNAcylation serves as a nutrient/stress sensor to modulate the functions of many nuclear and cytoplasmic proteins. O-GlcNAc cycles on serine or threonine residues like phosphorylation, is nearly as abundant, and functions, at least partially, via its interplay with phosphorylation. Here, we describe changes in site-specific phosphorylation dynamics in response to globally elevated GlcNAcylation. By combining sequential phospho-residue enrichment, iTRAQ labeling, and high throughput mass spectrometric analyses, phosphorylation dynamics on 711 phosphopeptides were quantified. Based upon their insensitivity to phosphatase inhibition, we conclude that approximately 48% of these phosphorylation sites were not actively cycling in the conditions of the study. However, increased GlcNAcylation influenced phosphate stoichiometry at most of the sites that did appear to be actively cycling. Elevated GlcNAcylation resulted in lower phosphorylation at 280 sites and caused increased phosphorylation at 148 sites. Thus, the cross-talk or interplay between these two abundant posttranslational modifications is extensive, and may arises both by steric competition for occupancy at the same or proximal sites and by each modification regulating the other's enzymatic machinery. The phosphoproteome dynamics presented by this large set of quantitative data not only delineates the complex interplay between phosphorylation and GlcNAcyation, but also provides insights for more focused investigations of specific roles of O-GlcNAc in regulating protein functions and signaling pathways.
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Affiliation(s)
- Zihao Wang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Marjan Gucek
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Gerald W. Hart
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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Butkinaree C, Cheung WD, Park S, Park K, Barber M, Hart GW. Characterization of beta-N-acetylglucosaminidase cleavage by caspase-3 during apoptosis. J Biol Chem 2008; 283:23557-66. [PMID: 18586680 DOI: 10.1074/jbc.m804116200] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Beta-O-linked N-acetylglucosamine is a dynamic post-translational modification involved in protein regulation in a manner similar to phosphorylation. Removal of N-acetylglucosamine is regulated by beta-N-acetylglucosaminidase (O-GlcNAcase), which was previously shown to be a substrate of caspase-3 in vitro. Here we show that O-GlcNAcase is cleaved by caspase-3 into two fragments during apoptosis, an N-terminal fragment containing the O-GlcNAcase active site and a C-terminal fragment containing a region with homology to GCN5 histone acetyl-transferases. The caspase-3 cleavage site of O-GlcNAcase, mapped by Edman sequencing, is a noncanonical recognition site that occurs after Asp-413 of the SVVD sequence in human O-GlcNAcase. A point mutation, D413A, abrogates cleavage by caspase-3 both in vitro and in vivo. Finally, we show that O-GlcNAcase activity is not affected by caspase-3 cleavage because the N- and C-terminal O-GlcNAcase fragments remain associated after the cleavage. Furthermore, when co-expressed simultaneously in the same cell, the N-terminal and C-terminal caspase fragments associate to reconstitute O-GlcNAcase enzymatic activity. These studies support the identification of O-GlcNAcase as a caspase-3 substrate with a novel caspase-3 cleavage site and provide insight about O-GlcNAcase regulation during apoptosis.
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Affiliation(s)
- Chutikarn Butkinaree
- Departments of Biological Chemistry and Neuroscience, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205-2185, USA
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Khwaja TA, Wajahat T, Ahmad I, Hoessli DC, Walker-Nasir E, Kaleem A, Qazi WM, Shakoori AR, Din NU. In silico modulation of apoptotic Bcl-2 proteins by mistletoe lectin-1: functional consequences of protein modifications. J Cell Biochem 2008; 103:479-91. [PMID: 17583555 DOI: 10.1002/jcb.21412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The mistletoe lectin-1 (ML-1) modulates tumor cell apoptosis by triggering signaling cascades through the complex interplay of phosphorylation and O-linked N-acetylglucosamine (O-GlcNAc) modification in pro- and anti-apoptotic proteins. In particular, ML-1 is predicted to induce dephosphorylation of Bcl-2-family proteins and their alternative O-GlcNAc modification at specific, conserved Ser/Thr residues. The sites for phosphorylation and glycosylation were predicted and analyzed using Netphos 2.0 and YinOYang 1.2. The involvement of modified Ser/Thr, and among them the potential Yin Yang sites that may undergo both types of posttranslational modification, is proposed to mediate apoptosis modulation by ML-1.
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Affiliation(s)
- Tasneem A Khwaja
- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan
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46
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Affiliation(s)
- Heather E. Murrey
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125
| | - Linda C. Hsieh-Wilson
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125
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Immunochemical methods for the rapid screening of the o-glycosidically linked N-acetylglucosamine modification of proteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008; 446:267-80. [PMID: 18373264 DOI: 10.1007/978-1-60327-084-7_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
for the rapid screening of specific post-translational modifications antibody-based methods are very well suited and applicable without demanding expenditure. Here we describe the immunochemical detection of the O-glycosidically linked cytosolic N-acetylglucosamine modification of proteins, which has attracted increasing interest in the last years. Two different monoclonal antibodies were used in enzyme-linked immunosorbent assays (ELISA), Western blots of 1- and 2- dimension (1D and 2D) separated proteins and immunohistochemical analysis of tissue sections. Slight differences in the recognition of this post-translational epitope by the 2 antibodies are observed and will be discussed.
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48
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Epidermal growth factor receptors: function modulation by phosphorylation and glycosylation interplay. Mol Biol Rep 2008; 36:631-9. [PMID: 18340549 DOI: 10.1007/s11033-008-9223-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 03/04/2008] [Indexed: 10/22/2022]
Abstract
Post-translational modifications (PTMs) of proteins induce structural and functional changes that are most often transitory and difficult to follow and investigate in vivo. In silico prediction procedures for PTMs are very valuable to foresee and define such transitory changes responsible for the multifunctionality of proteins. Epidermal growth factor receptor (EGFR) is such a multifunctional transmembrane protein with intrinsic tyrosine kinase activity that is regulated primarily by ligand-stimulated transphosphorylation of dimerized receptors. In human EGFR, potential phosphorylation sites on Ser, Thr and Tyr residues including five autophosphorylation sites on Tyr were investigated using in silico procedures. In addition to phosphorylation, O-GlcNAc modifications and interplay between these two modifications was also predicted. The interplay of phosphorylation and O-GlcNAc modification on same or neighboring Ser/Thr residues is termed as Yin Yang hypothesis and the interplay sites are named as Yin Yang sites. Amongst these modification sites, one residue is localized in the juxtamembrane (Thr 654) and two are found in the catalytic domain (Ser 1046/1047) of the EGFR. We propose that, when EGFR is O-GlcNAc modified on Thr 654, EGFR may be transferred from early to late endosomes, whereas when EGFR is O-GlcNAc modified on Ser 1046/1047 desensitization of the receptor may be prevented. These findings suggest a complex interplay between phosphorylation and O-GlcNAc modification resulting in modulation of EGFR's functionality.
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49
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Rexach JE, Clark PM, Hsieh-Wilson LC. Chemical approaches to understanding O-GlcNAc glycosylation in the brain. Nat Chem Biol 2008; 4:97-106. [PMID: 18202679 DOI: 10.1038/nchembio.68] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
O-GlcNAc glycosylation is a unique, dynamic form of glycosylation found on intracellular proteins of all multicellular organisms. Studies suggest that O-GlcNAc represents a key regulatory modification in the brain, contributing to transcriptional regulation, neuronal communication and neurodegenerative disease. Recently, several new chemical tools have been developed to detect and study the modification, including chemoenzymatic tagging methods, quantitative proteomics strategies and small-molecule inhibitors of O-GlcNAc enzymes. Here we highlight some of the emerging roles for O-GlcNAc in the nervous system and describe how chemical tools have significantly advanced our understanding of the scope, functional significance and cellular dynamics of this modification.
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Affiliation(s)
- Jessica E Rexach
- Division of Chemistry and Chemical Engineering, and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125, USA
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50
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Song M, Kim HS, Park JM, Kim SH, Kim IH, Ryu SH, Suh PG. o-GlcNAc transferase is activated by CaMKIV-dependent phosphorylation under potassium chloride-induced depolarization in NG-108-15 cells. Cell Signal 2007; 20:94-104. [PMID: 18029144 DOI: 10.1016/j.cellsig.2007.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 09/17/2007] [Accepted: 09/17/2007] [Indexed: 10/22/2022]
Abstract
Post-translational modification of cellular proteins by beta-o-linked N-acetylglucosamine (o-GlcNAc) moieties plays a significant role in signal transduction by modulating protein stability, protein-protein interactions, transactivation processes, and the enzyme activities of target proteins. Though various classes of proteins are known to be regulated by o-GlcNAc modification (o-GlcNAcylation), the mechanism that regulates o-linked GlcNAc transferase (OGT) activity remains unknown. Here, we report that potassium chloride-induced depolarization provokes the activation of OGT and subsequent o-GlcNAcylation of proteins in neuroblastoma NG-108-15 cells. Moreover, such an induction of protein o-GlcNAcylation was abolished by treating cells with either a voltage-gated calcium channel inhibitor or a calcium/calmodulin-dependent protein kinase (CaMK) inhibitor. In addition, CaMKIV was found to specifically phosphorylate and activate OGT in vivo and in vitro, which implies that CaMKIV is required for depolarization-induced activation of OGT. Furthermore, we found that OGT is involved in depolarization-induced and CaMKIV-dependent activation of activator protein-1 (AP-1) and subsequent tissue inhibitor of metalloproteinase-1 (Timp-1) gene expression. Taken together, our findings suggest that CaMKIV activated OGT, and OGT has an essential role on the process of CaMKIV-dependent AP-1 activation under depolarization in neuronal cells.
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Affiliation(s)
- Minseok Song
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Kyung-Buk 790-784, Republic of Korea
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