In light of the scarcity of reports on the interaction between HSV-1 nucleocapsid protein UL25 and its host cell proteins,the purpose of this study is to use yeast two-hybrid screening to search for cellular proteins ...In light of the scarcity of reports on the interaction between HSV-1 nucleocapsid protein UL25 and its host cell proteins,the purpose of this study is to use yeast two-hybrid screening to search for cellular proteins that can interact with the UL25 protein.C9orf69,a protein of unknown function was identified.The interaction between the two proteins under physiological conditions was also confirmed by biological experiments including co-localization by fluorescence and immunoprecipitation.A preliminary study of the function of C9orf69 showed that it promotes viral proliferation.Further studies showed that C9orf69 did not influence viral multiplication efficiency by transcriptional regulation of viral genes,but indirectly promoted proliferation via interaction with UL25.展开更多
The constant emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants indicates the evolution and adaptation of the virus.Enhanced innate immune evasion through increased expression of viral an...The constant emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants indicates the evolution and adaptation of the virus.Enhanced innate immune evasion through increased expression of viral antagonist proteins,including ORF9b,contributes to the improved transmission of the Alpha variant;hence,more attention should be paid to these viral proteins.ORF9b is an accessory protein that suppresses innate immunity via a monomer conformation by binding to Tom70.Here,we solved the dimeric structure of SARS-CoV-2 ORF9b with a long hydrophobic tunnel containing a lipid molecule that is crucial for the dimeric conformation and determined the specific lipid ligands as monoglycerides by conducting a liquid chromatography with tandem mass spectrometry analysis,suggesting an important role in the viral life cycle.Notably,a long intertwined loop accessible for host factor binding was observed in the structure.Eight phosphorylated residues in ORF9b were identified,and residues S50 and S53 were found to contribute to the stabilization of dimeric ORF9b.Additionally,we proposed a model of multifunctional ORF9b with a distinct conformation,suggesting that ORF9b is a fold-switching protein,while both lipids and phosphorylation contribute to the switching.Specifically,the ORF9b monomer interacts with Tom70 to suppress the innate immune response,whereas the ORF9b dimer binds to the membrane involving mature virion assembly.Our results provide a better understanding of the multiple functions of ORF9b.展开更多
GGGGCC repeat expansions in the C9 ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia(c9 ALS/FTD). It has been reported that hexanucleotide repeat expansions in C9 ORF72 ...GGGGCC repeat expansions in the C9 ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia(c9 ALS/FTD). It has been reported that hexanucleotide repeat expansions in C9 ORF72 produce five dipeptide repeat(DPR) proteins by an unconventional repeat-associated non-ATG(RAN)translation. Within the five DPR proteins, poly-PR and poly-GR that contain arginine are more toxic than the other DPRs(poly-GA, poly-GP, and poly-PA). Here, we demonstrated that poly-PR peptides transferred into cells by endocytosis in a clathrin-dependent manner, leading to endoplasmic reticulum stress and cell death. In SH-SY5 Y cells and primary cortical neurons, poly-PR activated JUN amino-terminal kinase(JNK) and increased the levels of p53 and Bax. The uptake of poly-PR peptides by cells was significantly inhibited by knockdown of clathrin or by chlorpromazine, an inhibitor that blocks clathrin-mediated endocytosis. Inhibition of clathrin-dependent endocytosis by chlorpromazine significantly blocked the transfer of poly-PR peptides into cells, and attenuated poly-PRinduced JNK activation and cell death. Our data revealed that the uptake of poly-PR undergoes clathrin-dependentendocytosis and blockade of this process prevents the toxic effects of synthetic poly-PR peptides.展开更多
Expansions of trinucleotide or hexanucleotide repeats lead to several neurodegenerative disorders,including Huntington disease[caused by expanded CAG repeats(CAGr)in the HTT gene],and amyotrophic lateral sclerosis[ALS...Expansions of trinucleotide or hexanucleotide repeats lead to several neurodegenerative disorders,including Huntington disease[caused by expanded CAG repeats(CAGr)in the HTT gene],and amyotrophic lateral sclerosis[ALS,possibly caused by expanded GGGGCC repeats(G4C2r)in the C9ORF72 gene],of which the molecular mechanisms remain unclear.Here,we demonstrated that lowering the Drosophila homologue of tau protein(dtau)significantly rescued in vivo neurodegeneration,motor performance impairments,and the shortened life-span in Drosophila expressing expanded CAGr or expanded G4C2r.Expression of human tau(htau4 R)restored the disease-related phenotypes that had been mitigated by the loss of dtau,suggesting an evolutionarily-conserved role of tau in neurodegeneration.We further revealed that G4C2r expression increased tau accumulation by inhibiting autophagosome-lysosome fusion,possibly due to lowering the level of BAG3,a regulator of autophagy and tau.Taken together,our results reveal a novel mechanism by which expanded G4C2r causes neurodegeneration via an evolutionarily-conserved mechanism.Our findings provide novel autophagy-related mechanistic insights into C9ORF72-ALS and possible entry points to disease treatment.展开更多
Amyotrophic lateral sclerosis（ALS）is a devastating neurodegenerative disorder characterized by loss of upper and lower motor neurons.Different mechanisms contribute to the disease initiation and progression,includin...Amyotrophic lateral sclerosis（ALS）is a devastating neurodegenerative disorder characterized by loss of upper and lower motor neurons.Different mechanisms contribute to the disease initiation and progression,including mitochondrial dysfunction which has been proposed to be a central determinant in ALS pathogenesis.Indeed,while mitochondrial defects have been mainly described in ALS-linked SOD1 mutants,it is now well established that mitochondria become also dysfunctional in other ALS conditions.In such context,the mitochondrial quality control system allows to restore normal functioning of mitochondria and to prevent cell death,by both eliminating and replacing damaged mitochondrial components or by degrading the entire organelle through mitophagy.Recent evidence shows that ALS-related genes interfere with the mitochondrial quality control system.This review highlights how ineffective mitochondrial quality control may render motor neurons defenseless towards the accumulating mitochondrial damage in ALS.展开更多
BACKGROUND Recent studies have proved the important role of many oncogenic long noncoding RNAs(lncRNAs) in the progression of pancreatic cancer, but little is known about the mechanisms of tumor suppression in pancrea...BACKGROUND Recent studies have proved the important role of many oncogenic long noncoding RNAs(lncRNAs) in the progression of pancreatic cancer, but little is known about the mechanisms of tumor suppression in pancreatic cancer.AIM To evaluate the function of tumor suppressor lncRNA C9orf139 in pancreatic cancer progression and to study the underlying mechanism.METHODS We assigned 54 patients with pancreatic ductal adenocarcinoma treated at our hospital to the patient group and 30 normal subjects undergoing physical examination to the control group. RT-qPCR was used to measure the relative expression of C9orf139 in the tissue and serum of patients, in an attempt to investigate the prognostic value of C9orf139 in pancreatic cancer patients. The luciferase reporter gene assay was performed to determine the interaction between C9orf139 and miR-663 a. The biological function of C9orf139 was assessed by in vitro assays and in vivo subcutaneous tumor formation tests in animal models. To figure out the molecular mechanism of C9orf139 to act on miR-663 a/Sox12, RNA pull-down, Western blot assay, RNA immunoprecipitation assay, and co-immunoprecipitation assay were performed.RESULTS C9orf139 level significantly increased in the tissue and serum of patients, which had clinical diagnostic value for pancreatic cancer. Patients with high C9orf139 expression had a higher risk of progressing to stage Ⅲ + Ⅳ, lymph node metastasis, and poor differentiation. Cox regression analysis suggested that C9orf139, tumor-node-metastasis stage, and lymph node metastasis were independent prognostic factors in patients. The underlying mechanism of C9orf139 was that it promoted the growth of pancreatic cancer cells by modulating the miR-663 a/Sox12 axis.CONCLUSION C9orf139 is highly expressed in pancreatic cancer, qualified to be used as a potential diagnostic and prognostic marker for pancreatic cancer. Its promotion of pancreatic cancer cell growth is achieved by mediating the miR-663 a/Sox12 axis.展开更多
基金Scientific Research Fund of the Institute of Pathogen Biology (2007IPB10)
文摘In light of the scarcity of reports on the interaction between HSV-1 nucleocapsid protein UL25 and its host cell proteins,the purpose of this study is to use yeast two-hybrid screening to search for cellular proteins that can interact with the UL25 protein.C9orf69,a protein of unknown function was identified.The interaction between the two proteins under physiological conditions was also confirmed by biological experiments including co-localization by fluorescence and immunoprecipitation.A preliminary study of the function of C9orf69 showed that it promotes viral proliferation.Further studies showed that C9orf69 did not influence viral multiplication efficiency by transcriptional regulation of viral genes,but indirectly promoted proliferation via interaction with UL25.
基金supported by the National Key Research and Development Projects of the Ministry of Science and Technology of China(2020YFC0845900,2021YFC2301300)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB29010202)+2 种基金the National Natural Science Foundation of China(82122040)supported by CAS Project for Young Scientists in Basic Research(YSBR-010)the Youth Innovation Promotion Association CAS。
文摘The constant emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants indicates the evolution and adaptation of the virus.Enhanced innate immune evasion through increased expression of viral antagonist proteins,including ORF9b,contributes to the improved transmission of the Alpha variant;hence,more attention should be paid to these viral proteins.ORF9b is an accessory protein that suppresses innate immunity via a monomer conformation by binding to Tom70.Here,we solved the dimeric structure of SARS-CoV-2 ORF9b with a long hydrophobic tunnel containing a lipid molecule that is crucial for the dimeric conformation and determined the specific lipid ligands as monoglycerides by conducting a liquid chromatography with tandem mass spectrometry analysis,suggesting an important role in the viral life cycle.Notably,a long intertwined loop accessible for host factor binding was observed in the structure.Eight phosphorylated residues in ORF9b were identified,and residues S50 and S53 were found to contribute to the stabilization of dimeric ORF9b.Additionally,we proposed a model of multifunctional ORF9b with a distinct conformation,suggesting that ORF9b is a fold-switching protein,while both lipids and phosphorylation contribute to the switching.Specifically,the ORF9b monomer interacts with Tom70 to suppress the innate immune response,whereas the ORF9b dimer binds to the membrane involving mature virion assembly.Our results provide a better understanding of the multiple functions of ORF9b.
基金supported by the National Natural Science Foundation of China (81761148024 and 31871023)the National Key Scientific R&D Program of China (2016YFC1306000)+1 种基金Suzhou Clinical Research Center of Neurological Disease (Szzx201503)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘GGGGCC repeat expansions in the C9 ORF72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia(c9 ALS/FTD). It has been reported that hexanucleotide repeat expansions in C9 ORF72 produce five dipeptide repeat(DPR) proteins by an unconventional repeat-associated non-ATG(RAN)translation. Within the five DPR proteins, poly-PR and poly-GR that contain arginine are more toxic than the other DPRs(poly-GA, poly-GP, and poly-PA). Here, we demonstrated that poly-PR peptides transferred into cells by endocytosis in a clathrin-dependent manner, leading to endoplasmic reticulum stress and cell death. In SH-SY5 Y cells and primary cortical neurons, poly-PR activated JUN amino-terminal kinase(JNK) and increased the levels of p53 and Bax. The uptake of poly-PR peptides by cells was significantly inhibited by knockdown of clathrin or by chlorpromazine, an inhibitor that blocks clathrin-mediated endocytosis. Inhibition of clathrin-dependent endocytosis by chlorpromazine significantly blocked the transfer of poly-PR peptides into cells, and attenuated poly-PRinduced JNK activation and cell death. Our data revealed that the uptake of poly-PR undergoes clathrin-dependentendocytosis and blockade of this process prevents the toxic effects of synthetic poly-PR peptides.
基金the National Natural Science Foundation of China(81925012 and 31961130379)a Newton Advanced Fellowship(NAF_R1_191045)。
文摘Expansions of trinucleotide or hexanucleotide repeats lead to several neurodegenerative disorders,including Huntington disease[caused by expanded CAG repeats(CAGr)in the HTT gene],and amyotrophic lateral sclerosis[ALS,possibly caused by expanded GGGGCC repeats(G4C2r)in the C9ORF72 gene],of which the molecular mechanisms remain unclear.Here,we demonstrated that lowering the Drosophila homologue of tau protein(dtau)significantly rescued in vivo neurodegeneration,motor performance impairments,and the shortened life-span in Drosophila expressing expanded CAGr or expanded G4C2r.Expression of human tau(htau4 R)restored the disease-related phenotypes that had been mitigated by the loss of dtau,suggesting an evolutionarily-conserved role of tau in neurodegeneration.We further revealed that G4C2r expression increased tau accumulation by inhibiting autophagosome-lysosome fusion,possibly due to lowering the level of BAG3,a regulator of autophagy and tau.Taken together,our results reveal a novel mechanism by which expanded G4C2r causes neurodegeneration via an evolutionarily-conserved mechanism.Our findings provide novel autophagy-related mechanistic insights into C9ORF72-ALS and possible entry points to disease treatment.
文摘Amyotrophic lateral sclerosis（ALS）is a devastating neurodegenerative disorder characterized by loss of upper and lower motor neurons.Different mechanisms contribute to the disease initiation and progression,including mitochondrial dysfunction which has been proposed to be a central determinant in ALS pathogenesis.Indeed,while mitochondrial defects have been mainly described in ALS-linked SOD1 mutants,it is now well established that mitochondria become also dysfunctional in other ALS conditions.In such context,the mitochondrial quality control system allows to restore normal functioning of mitochondria and to prevent cell death,by both eliminating and replacing damaged mitochondrial components or by degrading the entire organelle through mitophagy.Recent evidence shows that ALS-related genes interfere with the mitochondrial quality control system.This review highlights how ineffective mitochondrial quality control may render motor neurons defenseless towards the accumulating mitochondrial damage in ALS.
文摘BACKGROUND Recent studies have proved the important role of many oncogenic long noncoding RNAs(lncRNAs) in the progression of pancreatic cancer, but little is known about the mechanisms of tumor suppression in pancreatic cancer.AIM To evaluate the function of tumor suppressor lncRNA C9orf139 in pancreatic cancer progression and to study the underlying mechanism.METHODS We assigned 54 patients with pancreatic ductal adenocarcinoma treated at our hospital to the patient group and 30 normal subjects undergoing physical examination to the control group. RT-qPCR was used to measure the relative expression of C9orf139 in the tissue and serum of patients, in an attempt to investigate the prognostic value of C9orf139 in pancreatic cancer patients. The luciferase reporter gene assay was performed to determine the interaction between C9orf139 and miR-663 a. The biological function of C9orf139 was assessed by in vitro assays and in vivo subcutaneous tumor formation tests in animal models. To figure out the molecular mechanism of C9orf139 to act on miR-663 a/Sox12, RNA pull-down, Western blot assay, RNA immunoprecipitation assay, and co-immunoprecipitation assay were performed.RESULTS C9orf139 level significantly increased in the tissue and serum of patients, which had clinical diagnostic value for pancreatic cancer. Patients with high C9orf139 expression had a higher risk of progressing to stage Ⅲ + Ⅳ, lymph node metastasis, and poor differentiation. Cox regression analysis suggested that C9orf139, tumor-node-metastasis stage, and lymph node metastasis were independent prognostic factors in patients. The underlying mechanism of C9orf139 was that it promoted the growth of pancreatic cancer cells by modulating the miR-663 a/Sox12 axis.CONCLUSION C9orf139 is highly expressed in pancreatic cancer, qualified to be used as a potential diagnostic and prognostic marker for pancreatic cancer. Its promotion of pancreatic cancer cell growth is achieved by mediating the miR-663 a/Sox12 axis.
