目的:研究O-GlcNAcylation调节蛋白激酶C受体1(receptor for activated C kinase 1,Rack1)的稳定性在SHH型髓母细胞瘤(SHH type medulloblastoma,SHH-MB)形成中的功能作用。方法:选取中国人民解放军西部战区总医院临床肿瘤标本库中分子...目的:研究O-GlcNAcylation调节蛋白激酶C受体1(receptor for activated C kinase 1,Rack1)的稳定性在SHH型髓母细胞瘤(SHH type medulloblastoma,SHH-MB)形成中的功能作用。方法:选取中国人民解放军西部战区总医院临床肿瘤标本库中分子分型所确定的SHH-MB肿瘤及癌旁组织,分析样本中Rack1和O-GlcNAcylation(O-Glc NAc)的表达水平差异。对于人源髓母细胞瘤细胞系Daoy使用糖基化转移酶(OGT)抑制剂(OSMI-1)和去糖基化转移酶(OGA)抑制剂(TM-G)进行处理,通过Cell Counting Kit-8(CCK-8)法和免疫荧光染色检测肿瘤细胞增殖能力。采用O-Glc NAc酶标记系统、免疫共沉淀(Co-IP)和Western blot法判断Rack1有无发生O-Glc NAc,而后通过环己酰亚胺(CHX)实验和泛素化修饰实验证实O-GlcNAcylation对Rack1蛋白水平的影响。构建敲低Rack1的髓母细胞瘤模型,通过Cell Counting Kit-8(CCK-8)法、免疫荧光染色和划痕实验检测肿瘤细胞增殖能力。同时通过在免疫缺陷型小鼠进行异种原位肿瘤移植进行验证,在所得组织样本中(sh-NC和shRack1)使用Western blot检测下游SHH信号通路变化。结果:Rack1和O-GlcNAcylation在SHH-MB中表达水平显著增高,且Rack1表达水平和患者生存率呈负相关关系。对Daoy细胞系使用OSMI-1、TM-G处理后,发现O-Glc NAc能明显促进Daoy细胞增殖,而抑制细胞O-GlcNAc则抑制细胞增殖。分子实验证实Rack1蛋白O-GlcNAcylation可以调节其蛋白稳定性,进而促进肿瘤细胞增殖。在Daoy细胞系敲低Rack1表达,其细胞增殖能力明显低于对照组;在动物水平方面,相较于对照组,Rack1蛋白敲低的肿瘤组织增殖受到显著抑制。并且Rack1可通过调节SHH信号通路参与SHH-MB形成。结论:O-GlcNAcylation可通过调节Rack1蛋白的稳定性进而参与SHH-MB形成。展开更多
BACKGROUND Based on current knowledge,hepatocellular carcinoma(HCC)is a condition with numerous etiologies and risk factors.However,the pathogenesis of HCC remains unclear.AIM To investigate the roles of senegenin and...BACKGROUND Based on current knowledge,hepatocellular carcinoma(HCC)is a condition with numerous etiologies and risk factors.However,the pathogenesis of HCC remains unclear.AIM To investigate the roles of senegenin and O-GlcNAcylation in the growth and metastasis of HCC.METHODS The levels of O-linked N-acetylglucosamine transferase(OGT)and O-GlcNAcylation in HCC cells and tissues were detected using western blot analysis.The effects of senegenin and O-GlcNAcylation on the proliferation of HCC cells were investigated in vitro using cell counting kit-8 and clonogenic assays.The potential effects of senegenin and O-GlcNAcylation on HCC metastasis were examined using the transwell migration assay.O-GlcNAcylation levels were altered via drug treatment and lentiviral infection,and western blot analysis was used to detect proteins involved in various pathways.RESULTS Western blot analysis revealed that OGT and O-GlcNAcylation levels were significantly elevated in HCC tissues and cells.O-GlcNAcylation levels in HCC cells were significantly altered by drug treatment and lentiviral infection.An increase in the glycosylation level was linked to enhanced proliferation,invasiveness,clonogenicity,and metastatic potential of cancer cells.O-GlcNAcylation induced by senegenin was found to slow the proliferation and migration of HCC cells.The levels of proteins involved in nuclear factor-kappa B(NF-κB)and c-Jun N-terminal kinase(JNK)pathways,which are associated with endoplasmic reticulum stress,were altered.CONCLUSION Senegenin lowers O-GlcNAcylation levels,decreases OGT expression,and inhibits cancer cell growth and metastasis by regulating proteins involved in NF-κB and JNK pathways.展开更多
O-linked N-acetylglucosamine(O-GlcNAc)is a dynamic post-translational modification occurring on myriad proteins in the cell nucleus,cytoplasm,and mitochondria.The donor sugar for O-Glc NAcylation,uridine-diphosphate N...O-linked N-acetylglucosamine(O-GlcNAc)is a dynamic post-translational modification occurring on myriad proteins in the cell nucleus,cytoplasm,and mitochondria.The donor sugar for O-Glc NAcylation,uridine-diphosphate N-acetylglucosamine(UDP-Glc NAc),is synthesized from glucose through the hexosamine biosynthetic pathway(HBP).The recycling of O-GlcNAc on proteins is mediated by two enzymes in cells—O-GlcNAc transferase(OGT)and O-Glc NAcase(OGA),which catalyze the addition and removal of O-GlcNAc,respectively.O-GlcNAcylation is involved in a number of important cell processes including transcription,translation,metabolism,signal transduction,and apoptosis.Deregulation of O-GlcNAcylation has been reported to be associated with various human diseases such as cancer,diabetes,neurodegenerative diseases,and cardiovascular diseases.A better understanding of the roles of O-GlcNAcylation in physiopathological processes would help to uncover novel avenues for therapeutic intervention.The aim of this review is to discuss the recent updates on the mechanisms and impacts of O-GlcNAcylation on these diseases,and its potential as a new clinical target.展开更多
O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation...O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.展开更多
Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently be...Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.展开更多
Protein O-GlcNAcylation is a post-translational modification that links environmental stimuli with changes in intracellular signal pathways,and its disturbance has been found in neurodegenerative diseases and metaboli...Protein O-GlcNAcylation is a post-translational modification that links environmental stimuli with changes in intracellular signal pathways,and its disturbance has been found in neurodegenerative diseases and metabolic disorders.However,its role in the mesolimbic dopamine(DA)system,especially in the ventral tegmental area(VTA),needs to be elucidated.Here,we found that injection of Thiamet G,an O-GlcNAcase(OGA)inhibitor,in the VTA and nucleus accumbens(NAc)of mice,facilitated neuronal O-GlcNAcylation and decreased the operant response to sucrose as well as the latency to fall in rotarod test.Mice with DAergic neuron-specific knockout of O-GlcNAc transferase(OGT)displayed severe metabolic abnormalities and died within 4–8 weeks after birth.Furthermore,mice specifically overexpressing OGT in DAergic neurons in the VTA had learning defects in the operant response to sucrose,and impaired motor learning in the rotarod test.Instead,overexpression of OGT in GABAergic neurons in the VTA had no effect on these behaviors.These results suggest that protein O-GlcNAcylation of DAergic neurons in the VTA plays an important role in regulating the response to natural reward and motor learning in mice.展开更多
Benzo[a]pyrene(B[a]P)is a food contaminant toxic for cardiovascular diseases.The nuclear translocation of Arylhydrocarbon receptor(AhR)plays an important role in B[a]P-induced oxidative stress and vascular diseases.We...Benzo[a]pyrene(B[a]P)is a food contaminant toxic for cardiovascular diseases.The nuclear translocation of Arylhydrocarbon receptor(AhR)plays an important role in B[a]P-induced oxidative stress and vascular diseases.We confi rmed that B[a]P promoted ROS production in vascular smooth muscle cells(VSMCs)in vitro and in vivo,associated with the nuclear translocation of AhR.It is known that phosphorylation inhibits while dephosphorylation of AhR promotes nuclear translocation of AhR.However,from the posttranslational modifi cation level,the mechanism by which B[a]P activates and regulates the nuclear translocation of AhR is unclear.Co-immunoprecipitation results showed that cytoplasmic AhR was phosphorylated before B[a]P stimulation,and switched to O-GlcNAcylation upon B[a]P 1-h stimulation in VSMCs,suggesting there may be a competitively inhibitory relationship between O-GlcNAcylation and phosphorylation of AhR.Next,siRNAs of O-linked N-acetylglucosamine transferase(OGT),O-GlcNAcase(OGA)and OGA inhibitor PUGNAc were used.SiOGT blocks but siOGA and PUGNAc promote B[a]P-dependent AhR nuclear translocation and oxidative stress.Ser11 may be the competitive binding site for phosphorylation and O-GlcNAcylation of AhR.Phosphorylation-mimic variant inhibits but O-GlcNAcylation of AhR promotes AhR nuclear translocation and oxidative stress.Our fi ndings highlight a new perspective for AhR nuclear translocation regulated by the competitive modifi cation between phosphorylation and O-GlcNAcylation.展开更多
For a long time,colorectal cancer(CRC)has been ranked among the top cancerrelated mortality rates,threatening human health.As a significant posttranslational modification,O-GlcNAcylation plays an essential role in com...For a long time,colorectal cancer(CRC)has been ranked among the top cancerrelated mortality rates,threatening human health.As a significant posttranslational modification,O-GlcNAcylation plays an essential role in complex life activities.Related studies have found that the occurrence,development,and metastasis of CRC are all related to abnormal O-GlcNAcylation and participate in many critical biological processes,such as gene transcription,signal transduction,cell growth,and differentiation.Recently,nucleotide sugar analogs,tumorspecific carbohydrate vaccine,SIRT1 longevity gene,dendritic cells as targets,and NOTCH gene have become effective methods to induce antitumor therapy.Not long ago,checkpoint kinase 1 and checkpoint kinase 2 were used as therapeutic targets for CRC,but there are still many problems to be solved.With an in-depth study of protein chip,mass spectrometry,chromatography,and other technologies,O-GlcNAcylation research will accelerate rapidly,which may provide new ideas for the research and development of antitumor drugs and the discovery of new CRC diagnostic markers.展开更多
V(D)J recombination secures the production of functional immunoglobulin(Ig)genes and antibody diversity during the early stages of B-cell development through long-distance interactions mediated by cis-regulatory eleme...V(D)J recombination secures the production of functional immunoglobulin(Ig)genes and antibody diversity during the early stages of B-cell development through long-distance interactions mediated by cis-regulatory elements and trans-acting factors.O-GlcNAcylation is a dynamic and reversible posttranslational modification of nuclear and cytoplasmic proteins that regulates various protein functions,including DNA-binding affinity and protein-protein interactions.However,the effects of O-GlcNAcylation on proteins involved in V(D)J recombination remain largely unknown.To elucidate this relationship,we downregulated O-GlcNAcylation in a mouse model by administering an O-GlcNAc inhibitor or restricting the consumption of a regular diet.Interestingly,the inhibition of O-GlcNAcylation in mice severely impaired Ig heavy-chain(IgH)gene rearrangement.We identified several factors crucial for V(D)J recombination,including YY1,CTCF,SMC1,and SMC3,as direct targets of O-GlcNAc modification.Importantly,O-GlcNAcylation regulates the physical interaction between SMC1 and SMC3 and the DNA-binding patterns of YY1 at the IgH gene locus.Moreover,O-GlcNAc inhibition downregulated DDX5 protein expression,affecting the functional association of CTCF with its DNA-binding sites at the IgH locus.Our results showed that locus contraction and long-range interactions throughout the IgH locus are disrupted in a manner dependent on the cellular O-GlcNAc level.In this study,we established that V(D)J recombination relies on the O-GlcNAc status of stage-specific proteins during early B-cell development and identified O-GlcNAc-dependent mechanisms as new regulatory components for the development of a diverse antibody repertoire.展开更多
Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic...Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic adaptation in ovarian follicular selection.To date,the role and mechanism of hypoxia-inducible factor 1 subunit alpha(HIF1A)-mediated hypoxic responses in follicular atresia are unclear.This study aimed to investigate whether and how HIF1A regulates follicular atresia via the modulation of O-linked N-acetylglucosamine(O-GlcNAc)protein modification(O-GlcNAcylation).Results Our findings revealed that HIF1A was highly expressed in pig ovaries.Compared with that in healthy follicles,its expression was significantly downregulated in atretic follicles.Under hypoxic conditions,pharmacological inhibition or siRNA-mediated knockdown of HIF1A increased porcine GC apoptosis.Mechanistically,HIF1A knockdown Suppressed O-GlcNAc transferase degradation,leading to increased global O-GlcNAcylation.Using 4D labelfree quantitative proteomics,we identified 53 O-GlcNAcylated proteins.Importantly,O-GlcNAcylation stabilized vascular endothelial zinc finger 1(VEZF1),and HIF1A knockdown upregulated VEZF1 protein levels by promoting O-GlcNAcylation.The HIF1A-VEZF1 axis modulates forkhead box O1(FOXO1)expression by regulating endothelin-1.As a transcription factor,FOXO1 directly binds to the Bcl-2 associated X(BAX)promoter,activating its transcription and ultimately inducing porcine GC apoptosis and follicular atresia.Conclusion Overall,our study elucidates a novel molecular mechanism by which HIF1A deficiency modulates follicular atresia through O-GlcNAcylation-mediated VEZF1 expression.These results not only clarify the molecular mechanism of ovarian follicular development under hypoxic conditions but also offer potential targets for improving follicular selection efficiency in pig breeding.展开更多
Regulatory T cells(Tregs)establish dominant immune tolerance but obstruct tumor immune surveillance,warranting context-specific mechanistic insights into the functions of tumor-infiltrating Tregs(TIL-Tregs).We show th...Regulatory T cells(Tregs)establish dominant immune tolerance but obstruct tumor immune surveillance,warranting context-specific mechanistic insights into the functions of tumor-infiltrating Tregs(TIL-Tregs).We show that enhanced posttranslational O-linked N-acetylglucosamine modification(O-GlcNAcylation)of cellular factors is a molecular feature that promotes a tumor-specific gene expression signature and distinguishes TIL-Tregs from their systemic counterparts.We found that altered glucose utilization through the glucose transporter Glut3 is a major facilitator of this process.Treg-specific deletion of Glut3 abrogates tumor immune tolerance,while steady-state immune homeostasis remains largely unaffected in mice.Furthermore,by employing mouse tumor models and human clinical data,we identified the NF-κB subunit c-Rel as one such factor that,through Glut3-dependent O-GlcNAcylation,functionally orchestrates gene expression in Tregs at tumor sites.Together,these results not only identify immunometabolic alterations and molecular events contributing to fundamental aspects of Treg biology,specifically at tumor sites but also reveal tumor-specific cellular properties that can aid in the development of Treg-targeted cancer immunotherapies.展开更多
O-linked N-acetyl-glucosamine glycosylation(O-GlcNAcylation)of intracellular proteins is a dynamic process broadly implicated in age-related disease,yet it remains uncharacterized whether and how O-GlcNAcylation contr...O-linked N-acetyl-glucosamine glycosylation(O-GlcNAcylation)of intracellular proteins is a dynamic process broadly implicated in age-related disease,yet it remains uncharacterized whether and how O-GlcNAcylation contributes to the natural aging process.O-GlcNAc transferase(OGT)and the opposing enzyme O-GlcNAcase(OGA)control this nutrient-sensing protein modification in cells.Here,we show that global O-GlcNAc levels are increased in multiple tissues of aged mice.In aged liver,carbamoyl phosphate synthetase 1(CPS1)is among the most heavilyO-GlcNAcylated proteins.CPS1O-GlcNAcylation is reversed by calorie restriction and is sensitive to genetic and pharmacological manipulations of theO-GlcNAc pathway.High glucose stimulates CPS1O-GlcNAcylation and inhibits CPS1 activity.Liver-specific deletion of OGT potentiates CPS1 activity and renders CPS1 irresponsive to further stimulation by a prolonged fasting.Our results identify CPS1 O-GlcNAcylation as a key nutrient-sensing regulatory step in the urea cycle during aging and dietary restriction,implying a role for mitochondrial O-GlcNAcylation in nutritional regulation of longevity.展开更多
O-glycosylation of the nuclear pore complex(NPC)by O-linked N-acetylglucosamine(O-GlcNAc)is conserved within metazoans.Many nucleoporins(Nups)comprising the NPC are constitutively O-GlcNAcylated,but the functional rol...O-glycosylation of the nuclear pore complex(NPC)by O-linked N-acetylglucosamine(O-GlcNAc)is conserved within metazoans.Many nucleoporins(Nups)comprising the NPC are constitutively O-GlcNAcylated,but the functional role of this modification remains enigmatic.Weshowthat loss ofO-GlcNAc,induced by either inhibition ofO-GlcNAc transferase(OGT)or deletion of the gene encoding OGT,leads to decreased cellular levels of a number of natively O-GlcNAcylated Nups.Loss of O-GlcNAc enables increased ubiquitination of these Nups and their increased proteasomal degradation.The decreased half-life of these deglycosylated Nups manifests in their gradual loss from the NPC and a downstream malfunction of the nuclear pore selective permeability barrier in both dividing and post-mitotic cells.These findings define a critical role of O-GlcNAc modification of the NPC in maintaining its composition and the function of the selectivity filter.The results implicate NPC glycosylation as a regulator of NPC function and reveal the role of conserved glycosylation of the NPC among metazoans.展开更多
O-linkedβ-N-acetylglucosaminylation(O-GlcNAcylation)is a highly dynamic and widespread post-translational modification(PTM)that regulates the activity,subcellular localization,and stability of target proteins.O-GlcNA...O-linkedβ-N-acetylglucosaminylation(O-GlcNAcylation)is a highly dynamic and widespread post-translational modification(PTM)that regulates the activity,subcellular localization,and stability of target proteins.O-GlcNAcylation is a reversible PTM controlled by two cycling enzymes:O-linked N-acetylglucosamine transferase and O-GlcNAcase.Emerging evidence indicates that O-GlcNAcylation plays critical roles in innate immunity,inflammatory signaling,and cancer development.O-GlcNAcylation usually occurs on serine/threonine residues,where it interacts with other PTMs,such as phosphorylation.Thus,it likely has a broad regulatory scope.This review discusses the recent research advances regarding the regulatory roles of O-GlcNAcylation in innate immunity and inflammation.A more comprehensive understanding ofO-GlcNAcylation could help to optimize therapeutic strategies regarding inflammatory diseases and cancer.展开更多
Background and Aims:Recognition of excessive activa-tion of hepatic stellate cells(HSCs)in liver fibrosis prompt-ed us to investigate the regulatory mechanisms of HSCs.We aimed to examine the role of O-GlcNAcylation m...Background and Aims:Recognition of excessive activa-tion of hepatic stellate cells(HSCs)in liver fibrosis prompt-ed us to investigate the regulatory mechanisms of HSCs.We aimed to examine the role of O-GlcNAcylation modifica-tion of alanine,serine,cysteine transporter 2(ASCT2)in HSCs and liver fibrosis.Methods:The expression of O-Glc-NAcylation modification in fibrotic mice livers and activated HSCs was analyzed by western blotting.Immunoprecipita-tion was used to assess the interaction of ASCT2 and O-Glc-NAc transferase(OGT).In addition,ASCT2 protein stability was assayed after cycloheximide(CHX)treatment.The O-GlcNAcylation site of ASCT2 was predicted and mutated by site-directed mutagenesis.Real-time PCR,immunofluores-cence,kit determinations and Seahorse assays were used to clarify the effect of ASCT2 O-GlcNAcylation on HSC glu-taminolysis and HSC activation.Western blotting,immuno-chemistry,and immunohistofluorescence were used to ana-lyze the effect of ASCT2 O-GlcNAcylation in vivo.Results:We observed significantly increased O-GlcNAcylation modi-fication of ASCT2.ASCT2 was found to interact with OGT to regulate ASCT2 stability.We predicted and confirmed that O-GlcNAcylation of ASCT2 at Thr122 site resulted in HSCs activation.We found Thr122 O-GlcNAcylation of ASCT2 me-diated membrane trafficking of glutamine transport and attenuated HSC glutaminolysis.Finally,we validated the expression and function of ASCT2 O-GlcNAcylation after in-jection of AAV8-ASCT2 shRNA in CCl4-induced liver fibrosis mice in vivo.Conclusions:Thr122 O-GlcNAcylation regu-lation of ASCT2 resulted in stability and membrane traf-ficking-mediated glutaminolysis in HSCs and liver fibrosis.Further studies are required to assess its role as a putative therapeutic target.展开更多
2025年3月24日,《分子细胞》(Molecular Cell)在线发表了浙江大学医学院吕志民教授团队的研究成果“PI3Kβfunctions as a protein kinase to promote cellular protein O-GlcNAcylation and acetyl-CoA production for tumor growth”(...2025年3月24日,《分子细胞》(Molecular Cell)在线发表了浙江大学医学院吕志民教授团队的研究成果“PI3Kβfunctions as a protein kinase to promote cellular protein O-GlcNAcylation and acetyl-CoA production for tumor growth”(DOI:10.1016/j.molcel.2025.02.024)。展开更多
Investigations from the last four decades have correlated high O-linked N-acetylglucosamine(O-Glc NAc)levels with various cancer types,but it is not known how OGT responds to diverse nutrients to finetune cellular O-G...Investigations from the last four decades have correlated high O-linked N-acetylglucosamine(O-Glc NAc)levels with various cancer types,but it is not known how OGT responds to diverse nutrients to finetune cellular O-Glc NAcylation levels.Herein we identified a critical OGT phosphorylation site by unc-51 like autophagy activating kinase 1(ULK1)under glucose depletion.First,we demonstrated that glucose levels modulate the interaction between OGT and ULK1 and cellular O-Glc NAcylation levels.Low glucose induces high O-Glc NAcylation,which could be reversed by ULK1 inhibition.Then,using mass spectrometry,we showed that ULK1 phosphorylates OGT at Ser576 and stabilizes OGT.Further biochemical experiments revealed that Ser576 phosphorylation inhibits Lys604 ubiquitination by stimulating OGT binding with BAP1,a de-ubiquitinase for OGT.Strikingly,using the OGT S576A knock-in cells,we found that in mouse xenograft models OGTS576A completely abolishes the tumorigenicity of OGT,probably due to low O-Glc NAcylation.In sum,we found that ULK1 phosphorylates OGT at Ser-576 under glucose deprivation,which stabilizes OGT by promoting OGT-BAP1 association and is pivotal for O-Glc NAcylation levels and tumorigenesis.As low glucose is often associated with tumor progression,our work not only unearths a key mechanism of how OGT is regulated by glucose levels,but also offers new therapeutic opportunities targeting OGT.展开更多
Cumulative evidence suggests that O-linkedβ-N-acetylglucosaminylation(OGlcNAcylation)plays an important regulatory role in pathophysiological processes.Although the regulatory mechanisms of O-GlcNAcylation in tumors ...Cumulative evidence suggests that O-linkedβ-N-acetylglucosaminylation(OGlcNAcylation)plays an important regulatory role in pathophysiological processes.Although the regulatory mechanisms of O-GlcNAcylation in tumors have been gradually elucidated,the potential mechanisms of O-GlcNAcylation in bone metabolism,particularly,in the osteogenic differentiation of bone marrow mesenchymal stromal cells(BMSCs)remains unexplored.In this study,the literature related to O-GlcNAcylation and BMSC osteogenic differentiation was reviewed,assuming that it could trigger more scholars to focus on research related to OGlcNAcylation and bone metabolism and provide insights into the development of novel therapeutic targets for bone metabolism disorders such as osteoporosis.展开更多
文摘BACKGROUND Based on current knowledge,hepatocellular carcinoma(HCC)is a condition with numerous etiologies and risk factors.However,the pathogenesis of HCC remains unclear.AIM To investigate the roles of senegenin and O-GlcNAcylation in the growth and metastasis of HCC.METHODS The levels of O-linked N-acetylglucosamine transferase(OGT)and O-GlcNAcylation in HCC cells and tissues were detected using western blot analysis.The effects of senegenin and O-GlcNAcylation on the proliferation of HCC cells were investigated in vitro using cell counting kit-8 and clonogenic assays.The potential effects of senegenin and O-GlcNAcylation on HCC metastasis were examined using the transwell migration assay.O-GlcNAcylation levels were altered via drug treatment and lentiviral infection,and western blot analysis was used to detect proteins involved in various pathways.RESULTS Western blot analysis revealed that OGT and O-GlcNAcylation levels were significantly elevated in HCC tissues and cells.O-GlcNAcylation levels in HCC cells were significantly altered by drug treatment and lentiviral infection.An increase in the glycosylation level was linked to enhanced proliferation,invasiveness,clonogenicity,and metastatic potential of cancer cells.O-GlcNAcylation induced by senegenin was found to slow the proliferation and migration of HCC cells.The levels of proteins involved in nuclear factor-kappa B(NF-κB)and c-Jun N-terminal kinase(JNK)pathways,which are associated with endoplasmic reticulum stress,were altered.CONCLUSION Senegenin lowers O-GlcNAcylation levels,decreases OGT expression,and inhibits cancer cell growth and metastasis by regulating proteins involved in NF-κB and JNK pathways.
基金supported by the National Natural Science Foundation of China(Nos.91753125,31270865,31322019,and 31570804)the National Key Research and Development Program of China(No.2016YFA0100303)the Zhejiang Provincial Natural Science Foundation of China(No.LR15C050001)
文摘O-linked N-acetylglucosamine(O-GlcNAc)is a dynamic post-translational modification occurring on myriad proteins in the cell nucleus,cytoplasm,and mitochondria.The donor sugar for O-Glc NAcylation,uridine-diphosphate N-acetylglucosamine(UDP-Glc NAc),is synthesized from glucose through the hexosamine biosynthetic pathway(HBP).The recycling of O-GlcNAc on proteins is mediated by two enzymes in cells—O-GlcNAc transferase(OGT)and O-Glc NAcase(OGA),which catalyze the addition and removal of O-GlcNAc,respectively.O-GlcNAcylation is involved in a number of important cell processes including transcription,translation,metabolism,signal transduction,and apoptosis.Deregulation of O-GlcNAcylation has been reported to be associated with various human diseases such as cancer,diabetes,neurodegenerative diseases,and cardiovascular diseases.A better understanding of the roles of O-GlcNAcylation in physiopathological processes would help to uncover novel avenues for therapeutic intervention.The aim of this review is to discuss the recent updates on the mechanisms and impacts of O-GlcNAcylation on these diseases,and its potential as a new clinical target.
基金supported by grants from the National Natural Science Foundation of China (32100549 and 31991193)
文摘O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.
基金This project has been supported by the National Natural Science Foundation of China(grants 91853108,92153301,31771589,and 32170821 to K.Y,32101034 to F.C)Department of Science and Technology of Hunan Province(grants 2017RS3013,2017XK2011,2018DK2015,2019SK1012,and 2021JJ10054 to K.Y,and the innovative team program 2019RS1010)+2 种基金Central South University(2018CX032 to K.Y,2019zzts046 to Y.Z,2019zzts339 to X.L,2021zzts497 to H.Y,and the innovation-driven team project 2020CX016)D.M.F.v.A.is supported by Wellcome Trust Investigator Award(110061)a Novo Nordisk Foundation Laureate award(NNF21OC0065969).
文摘Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.
基金the National Natural Science Foundation of China(31871021,82021002,31930046,and 32000671)the China Postdoctoral Science Foundation(2020M670978 and 2021T140127)the Shanghai Municipal Science and Technology Major Project(2018SHZDZX01),and ZhangJiang Lab.
文摘Protein O-GlcNAcylation is a post-translational modification that links environmental stimuli with changes in intracellular signal pathways,and its disturbance has been found in neurodegenerative diseases and metabolic disorders.However,its role in the mesolimbic dopamine(DA)system,especially in the ventral tegmental area(VTA),needs to be elucidated.Here,we found that injection of Thiamet G,an O-GlcNAcase(OGA)inhibitor,in the VTA and nucleus accumbens(NAc)of mice,facilitated neuronal O-GlcNAcylation and decreased the operant response to sucrose as well as the latency to fall in rotarod test.Mice with DAergic neuron-specific knockout of O-GlcNAc transferase(OGT)displayed severe metabolic abnormalities and died within 4–8 weeks after birth.Furthermore,mice specifically overexpressing OGT in DAergic neurons in the VTA had learning defects in the operant response to sucrose,and impaired motor learning in the rotarod test.Instead,overexpression of OGT in GABAergic neurons in the VTA had no effect on these behaviors.These results suggest that protein O-GlcNAcylation of DAergic neurons in the VTA plays an important role in regulating the response to natural reward and motor learning in mice.
基金supported by the National Key Research Project of China(2022YFF1100300)National Natural Science Foundation of China(32272328)+5 种基金Natural Science Foundation of Hebei Province(B2022321001)Major Public Welfare Projects in Henan Province(201300110200)National Key Research Project of Hebei Province(20375502D)National Key Research Project of Hebei Province(H2021206427)University Science and Technology Research Project of Hebei Province(QN2017107)Postdoctoral Research Funds of Hebei Medical University(307050100163759).
文摘Benzo[a]pyrene(B[a]P)is a food contaminant toxic for cardiovascular diseases.The nuclear translocation of Arylhydrocarbon receptor(AhR)plays an important role in B[a]P-induced oxidative stress and vascular diseases.We confi rmed that B[a]P promoted ROS production in vascular smooth muscle cells(VSMCs)in vitro and in vivo,associated with the nuclear translocation of AhR.It is known that phosphorylation inhibits while dephosphorylation of AhR promotes nuclear translocation of AhR.However,from the posttranslational modifi cation level,the mechanism by which B[a]P activates and regulates the nuclear translocation of AhR is unclear.Co-immunoprecipitation results showed that cytoplasmic AhR was phosphorylated before B[a]P stimulation,and switched to O-GlcNAcylation upon B[a]P 1-h stimulation in VSMCs,suggesting there may be a competitively inhibitory relationship between O-GlcNAcylation and phosphorylation of AhR.Next,siRNAs of O-linked N-acetylglucosamine transferase(OGT),O-GlcNAcase(OGA)and OGA inhibitor PUGNAc were used.SiOGT blocks but siOGA and PUGNAc promote B[a]P-dependent AhR nuclear translocation and oxidative stress.Ser11 may be the competitive binding site for phosphorylation and O-GlcNAcylation of AhR.Phosphorylation-mimic variant inhibits but O-GlcNAcylation of AhR promotes AhR nuclear translocation and oxidative stress.Our fi ndings highlight a new perspective for AhR nuclear translocation regulated by the competitive modifi cation between phosphorylation and O-GlcNAcylation.
文摘For a long time,colorectal cancer(CRC)has been ranked among the top cancerrelated mortality rates,threatening human health.As a significant posttranslational modification,O-GlcNAcylation plays an essential role in complex life activities.Related studies have found that the occurrence,development,and metastasis of CRC are all related to abnormal O-GlcNAcylation and participate in many critical biological processes,such as gene transcription,signal transduction,cell growth,and differentiation.Recently,nucleotide sugar analogs,tumorspecific carbohydrate vaccine,SIRT1 longevity gene,dendritic cells as targets,and NOTCH gene have become effective methods to induce antitumor therapy.Not long ago,checkpoint kinase 1 and checkpoint kinase 2 were used as therapeutic targets for CRC,but there are still many problems to be solved.With an in-depth study of protein chip,mass spectrometry,chromatography,and other technologies,O-GlcNAcylation research will accelerate rapidly,which may provide new ideas for the research and development of antitumor drugs and the discovery of new CRC diagnostic markers.
基金supported by a National Research Foundation(NRF)grant from Korea funded by the Ministry of Education(2021R1I1A2057945 to S-KP)the Ministry of Science&ICT(2020R1I1A3073845 to AKP,and 2021R1A2C1012477 to JL)+1 种基金the National Research Council of Science&Technology(NST)(GTL24021-000 to T-DK,GTL24021-400 to HH,and ZYM9382312 to Y-JK as the Postdoctoral Fellowship Program for Young Scientists)the Korea Research Institute of Bioscience and Biotechnology(KRIBB)Research Initiative Program(KGM9942421).
文摘V(D)J recombination secures the production of functional immunoglobulin(Ig)genes and antibody diversity during the early stages of B-cell development through long-distance interactions mediated by cis-regulatory elements and trans-acting factors.O-GlcNAcylation is a dynamic and reversible posttranslational modification of nuclear and cytoplasmic proteins that regulates various protein functions,including DNA-binding affinity and protein-protein interactions.However,the effects of O-GlcNAcylation on proteins involved in V(D)J recombination remain largely unknown.To elucidate this relationship,we downregulated O-GlcNAcylation in a mouse model by administering an O-GlcNAc inhibitor or restricting the consumption of a regular diet.Interestingly,the inhibition of O-GlcNAcylation in mice severely impaired Ig heavy-chain(IgH)gene rearrangement.We identified several factors crucial for V(D)J recombination,including YY1,CTCF,SMC1,and SMC3,as direct targets of O-GlcNAc modification.Importantly,O-GlcNAcylation regulates the physical interaction between SMC1 and SMC3 and the DNA-binding patterns of YY1 at the IgH gene locus.Moreover,O-GlcNAc inhibition downregulated DDX5 protein expression,affecting the functional association of CTCF with its DNA-binding sites at the IgH locus.Our results showed that locus contraction and long-range interactions throughout the IgH locus are disrupted in a manner dependent on the cellular O-GlcNAc level.In this study,we established that V(D)J recombination relies on the O-GlcNAc status of stage-specific proteins during early B-cell development and identified O-GlcNAc-dependent mechanisms as new regulatory components for the development of a diverse antibody repertoire.
基金supported by the National Natural Science Foundation of China(32402710)National Postdoctoral Researchers Funding Program(GZC20232209)+1 种基金Higher Education Institutions Basic Science(Natural Science)Research General Program of Jiangsu Province(24KJB230005)Priority Academic Program Development of Jiangsu Higher Education Institution.
文摘Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic adaptation in ovarian follicular selection.To date,the role and mechanism of hypoxia-inducible factor 1 subunit alpha(HIF1A)-mediated hypoxic responses in follicular atresia are unclear.This study aimed to investigate whether and how HIF1A regulates follicular atresia via the modulation of O-linked N-acetylglucosamine(O-GlcNAc)protein modification(O-GlcNAcylation).Results Our findings revealed that HIF1A was highly expressed in pig ovaries.Compared with that in healthy follicles,its expression was significantly downregulated in atretic follicles.Under hypoxic conditions,pharmacological inhibition or siRNA-mediated knockdown of HIF1A increased porcine GC apoptosis.Mechanistically,HIF1A knockdown Suppressed O-GlcNAc transferase degradation,leading to increased global O-GlcNAcylation.Using 4D labelfree quantitative proteomics,we identified 53 O-GlcNAcylated proteins.Importantly,O-GlcNAcylation stabilized vascular endothelial zinc finger 1(VEZF1),and HIF1A knockdown upregulated VEZF1 protein levels by promoting O-GlcNAcylation.The HIF1A-VEZF1 axis modulates forkhead box O1(FOXO1)expression by regulating endothelin-1.As a transcription factor,FOXO1 directly binds to the Bcl-2 associated X(BAX)promoter,activating its transcription and ultimately inducing porcine GC apoptosis and follicular atresia.Conclusion Overall,our study elucidates a novel molecular mechanism by which HIF1A deficiency modulates follicular atresia through O-GlcNAcylation-mediated VEZF1 expression.These results not only clarify the molecular mechanism of ovarian follicular development under hypoxic conditions but also offer potential targets for improving follicular selection efficiency in pig breeding.
基金YC was financially supported by the Dissertation Completion Award of the University of Georgia and American Lebanese Syrian Associated Charities(ALSAC)at St.Jude Children’s Research HospitalAG acknowledges support by the High Performance and Cloud Computing Group at the Zentrum für Datenverarbeitung of the University of Tübingen,the state of Baden-Württemberg through bwHPC and the German Research Foundation(DFG)through grant no INST 37/935-1 FUGG,and the de.NBI Cloud within the German Network for Bioinformatics Infrastructure(de.NBI)and ELIXIR-DE(Forschungszentrum Jülich and W-de.NBI-001,W-de.NBI-004,W-de.NBI-008,W-de.NBI-010,W-de.NBI-013,W-de.NBI-014,W-de.NBI-016,W-de.NBI-022)for supporting the computational analysis carried out in this work.AS was supported by BrainKorea21 Plus scholarship from the National Research Foundation of Korea(NRF)+1 种基金This research,in part,was supported by the Basic Science Research Program(grant#4.24643.01)funded by the Ministry of Education,Korea,and NRF grants#RS-2023-00260454(AS)and RS-2024-00345575(SHI)funded by the Korea Ministry of Science and ICT(MSIT)DR is recipient of National Natural Science Foundation of China grant#32470980.
文摘Regulatory T cells(Tregs)establish dominant immune tolerance but obstruct tumor immune surveillance,warranting context-specific mechanistic insights into the functions of tumor-infiltrating Tregs(TIL-Tregs).We show that enhanced posttranslational O-linked N-acetylglucosamine modification(O-GlcNAcylation)of cellular factors is a molecular feature that promotes a tumor-specific gene expression signature and distinguishes TIL-Tregs from their systemic counterparts.We found that altered glucose utilization through the glucose transporter Glut3 is a major facilitator of this process.Treg-specific deletion of Glut3 abrogates tumor immune tolerance,while steady-state immune homeostasis remains largely unaffected in mice.Furthermore,by employing mouse tumor models and human clinical data,we identified the NF-κB subunit c-Rel as one such factor that,through Glut3-dependent O-GlcNAcylation,functionally orchestrates gene expression in Tregs at tumor sites.Together,these results not only identify immunometabolic alterations and molecular events contributing to fundamental aspects of Treg biology,specifically at tumor sites but also reveal tumor-specific cellular properties that can aid in the development of Treg-targeted cancer immunotherapies.
基金was supported by grants from National Institutes of Health(R01DK089098 and P01DK57751)American Diabetes Association(1-19-IBS-119)+1 种基金X.Y.and a Glenn/AFAR Scholarship for Research in the Biology of Aging to M.-D.LYale School of Medicine and by the Office of The Director,National Institutes of Health(S10OD02365101A1,S10OD019967,and S10OD018034).
文摘O-linked N-acetyl-glucosamine glycosylation(O-GlcNAcylation)of intracellular proteins is a dynamic process broadly implicated in age-related disease,yet it remains uncharacterized whether and how O-GlcNAcylation contributes to the natural aging process.O-GlcNAc transferase(OGT)and the opposing enzyme O-GlcNAcase(OGA)control this nutrient-sensing protein modification in cells.Here,we show that global O-GlcNAc levels are increased in multiple tissues of aged mice.In aged liver,carbamoyl phosphate synthetase 1(CPS1)is among the most heavilyO-GlcNAcylated proteins.CPS1O-GlcNAcylation is reversed by calorie restriction and is sensitive to genetic and pharmacological manipulations of theO-GlcNAc pathway.High glucose stimulates CPS1O-GlcNAcylation and inhibits CPS1 activity.Liver-specific deletion of OGT potentiates CPS1 activity and renders CPS1 irresponsive to further stimulation by a prolonged fasting.Our results identify CPS1 O-GlcNAcylation as a key nutrient-sensing regulatory step in the urea cycle during aging and dietary restriction,implying a role for mitochondrial O-GlcNAcylation in nutritional regulation of longevity.
基金supported by a Discovery Grant(grant no.RGPIN/298406-2010)fromthe Natural Sciences and Engineering Research(NSERC),and the Canadian Institutes of Health Research(CIHR)(grant no.MOP-123341).Y.Z.thanks the CIHR for support through a postdoctoral fellowship.D.J.V.acknowledges the kind support of the Canada Research Chairs Program for a Tier I Canada Research Chair in Chemical Glycobiology and NSERC for support as an E.W.R.Steacie Memorial Fellow.N.Z.acknowledges the support from the National Heart Lung and Blood Institute(P01HL107153).
文摘O-glycosylation of the nuclear pore complex(NPC)by O-linked N-acetylglucosamine(O-GlcNAc)is conserved within metazoans.Many nucleoporins(Nups)comprising the NPC are constitutively O-GlcNAcylated,but the functional role of this modification remains enigmatic.Weshowthat loss ofO-GlcNAc,induced by either inhibition ofO-GlcNAc transferase(OGT)or deletion of the gene encoding OGT,leads to decreased cellular levels of a number of natively O-GlcNAcylated Nups.Loss of O-GlcNAc enables increased ubiquitination of these Nups and their increased proteasomal degradation.The decreased half-life of these deglycosylated Nups manifests in their gradual loss from the NPC and a downstream malfunction of the nuclear pore selective permeability barrier in both dividing and post-mitotic cells.These findings define a critical role of O-GlcNAc modification of the NPC in maintaining its composition and the function of the selectivity filter.The results implicate NPC glycosylation as a regulator of NPC function and reveal the role of conserved glycosylation of the NPC among metazoans.
基金The current work was supported by a special program from the Ministry of Science and Technology of China(2021YFA1101000)the National Natural Science Foundation of China(U20A20393,32125016,31871405,31925013,31870902,and 32070907)+1 种基金Jiangsu National Science Foundation(19KJA550003)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘O-linkedβ-N-acetylglucosaminylation(O-GlcNAcylation)is a highly dynamic and widespread post-translational modification(PTM)that regulates the activity,subcellular localization,and stability of target proteins.O-GlcNAcylation is a reversible PTM controlled by two cycling enzymes:O-linked N-acetylglucosamine transferase and O-GlcNAcase.Emerging evidence indicates that O-GlcNAcylation plays critical roles in innate immunity,inflammatory signaling,and cancer development.O-GlcNAcylation usually occurs on serine/threonine residues,where it interacts with other PTMs,such as phosphorylation.Thus,it likely has a broad regulatory scope.This review discusses the recent research advances regarding the regulatory roles of O-GlcNAcylation in innate immunity and inflammation.A more comprehensive understanding ofO-GlcNAcylation could help to optimize therapeutic strategies regarding inflammatory diseases and cancer.
基金the Leading Talent Project of Ji-angsu Province Traditional Chinese Medicine(SLJ0216)the National Natural Science Foundation of China(82073914,81870423)+2 种基金the Major Project of the Natural Science Research of Jiangsu Higher Education Institutions(19KJA310005)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:KYCX20_1493the Joint Project of Jiangsu Key Laboratory for Pharmacol-ogy and Safety Evaluation of Chinese Materia Medica and Yangtze River Pharmaceutical(JKLPSE202005)。
文摘Background and Aims:Recognition of excessive activa-tion of hepatic stellate cells(HSCs)in liver fibrosis prompt-ed us to investigate the regulatory mechanisms of HSCs.We aimed to examine the role of O-GlcNAcylation modifica-tion of alanine,serine,cysteine transporter 2(ASCT2)in HSCs and liver fibrosis.Methods:The expression of O-Glc-NAcylation modification in fibrotic mice livers and activated HSCs was analyzed by western blotting.Immunoprecipita-tion was used to assess the interaction of ASCT2 and O-Glc-NAc transferase(OGT).In addition,ASCT2 protein stability was assayed after cycloheximide(CHX)treatment.The O-GlcNAcylation site of ASCT2 was predicted and mutated by site-directed mutagenesis.Real-time PCR,immunofluores-cence,kit determinations and Seahorse assays were used to clarify the effect of ASCT2 O-GlcNAcylation on HSC glu-taminolysis and HSC activation.Western blotting,immuno-chemistry,and immunohistofluorescence were used to ana-lyze the effect of ASCT2 O-GlcNAcylation in vivo.Results:We observed significantly increased O-GlcNAcylation modi-fication of ASCT2.ASCT2 was found to interact with OGT to regulate ASCT2 stability.We predicted and confirmed that O-GlcNAcylation of ASCT2 at Thr122 site resulted in HSCs activation.We found Thr122 O-GlcNAcylation of ASCT2 me-diated membrane trafficking of glutamine transport and attenuated HSC glutaminolysis.Finally,we validated the expression and function of ASCT2 O-GlcNAcylation after in-jection of AAV8-ASCT2 shRNA in CCl4-induced liver fibrosis mice in vivo.Conclusions:Thr122 O-GlcNAcylation regu-lation of ASCT2 resulted in stability and membrane traf-ficking-mediated glutaminolysis in HSCs and liver fibrosis.Further studies are required to assess its role as a putative therapeutic target.
文摘2025年3月24日,《分子细胞》(Molecular Cell)在线发表了浙江大学医学院吕志民教授团队的研究成果“PI3Kβfunctions as a protein kinase to promote cellular protein O-GlcNAcylation and acetyl-CoA production for tumor growth”(DOI:10.1016/j.molcel.2025.02.024)。
基金supported by the National Natural Science Foundation of China(NSFC)(92478113,32271285,32071277,82103383)Guangdong Province Basic Research Foundation(2023A1515011842)the Shenzhen Basic Research Foundation(JCYJ20230807095300002)。
文摘Investigations from the last four decades have correlated high O-linked N-acetylglucosamine(O-Glc NAc)levels with various cancer types,but it is not known how OGT responds to diverse nutrients to finetune cellular O-Glc NAcylation levels.Herein we identified a critical OGT phosphorylation site by unc-51 like autophagy activating kinase 1(ULK1)under glucose depletion.First,we demonstrated that glucose levels modulate the interaction between OGT and ULK1 and cellular O-Glc NAcylation levels.Low glucose induces high O-Glc NAcylation,which could be reversed by ULK1 inhibition.Then,using mass spectrometry,we showed that ULK1 phosphorylates OGT at Ser576 and stabilizes OGT.Further biochemical experiments revealed that Ser576 phosphorylation inhibits Lys604 ubiquitination by stimulating OGT binding with BAP1,a de-ubiquitinase for OGT.Strikingly,using the OGT S576A knock-in cells,we found that in mouse xenograft models OGTS576A completely abolishes the tumorigenicity of OGT,probably due to low O-Glc NAcylation.In sum,we found that ULK1 phosphorylates OGT at Ser-576 under glucose deprivation,which stabilizes OGT by promoting OGT-BAP1 association and is pivotal for O-Glc NAcylation levels and tumorigenesis.As low glucose is often associated with tumor progression,our work not only unearths a key mechanism of how OGT is regulated by glucose levels,but also offers new therapeutic opportunities targeting OGT.
文摘Cumulative evidence suggests that O-linkedβ-N-acetylglucosaminylation(OGlcNAcylation)plays an important regulatory role in pathophysiological processes.Although the regulatory mechanisms of O-GlcNAcylation in tumors have been gradually elucidated,the potential mechanisms of O-GlcNAcylation in bone metabolism,particularly,in the osteogenic differentiation of bone marrow mesenchymal stromal cells(BMSCs)remains unexplored.In this study,the literature related to O-GlcNAcylation and BMSC osteogenic differentiation was reviewed,assuming that it could trigger more scholars to focus on research related to OGlcNAcylation and bone metabolism and provide insights into the development of novel therapeutic targets for bone metabolism disorders such as osteoporosis.
