TANK-binding kinase 1(TBK1)is an essential protein kinase for activation of interferon regulatory factor 3(IRF3)and induction of the type I interferons(IFN-I).Although the biochemical regulation of TBK1 activation has...TANK-binding kinase 1(TBK1)is an essential protein kinase for activation of interferon regulatory factor 3(IRF3)and induction of the type I interferons(IFN-I).Although the biochemical regulation of TBK1 activation has been studied,little is known about how enterovirus 71(EV71)employs the deubiquitinases(DUBs)to regulate TBK1 activation for viral immune evasion.Here,we found that EV71 infection upregulated the expression of ubiquitinspecific protease 24(USP24).Further studies revealed that USP24 physically interacted with TBK1,and can reduce K63-linked polyubiquitination of TBK1.Knockdown of USP24 upregulated TBK1 K63-linked polyubiquitination,promoted the phosphorylation and nuclear translocation of IRF3,and in turn improved IFN-I production during EV71 infection.As a consequence,USP24 knockdown dramatically inhibited EV71 infection.This study revealed USP24 as a novel regulator of TBK1 activation,which promotes the understanding of immune evasion mechanisms of EV71 and could provide a potential strategy for treatment of EV71 infection.展开更多
The Enterovirus 71(EV71)VP4 is co-translationally linked to myristic acid at its amino-terminal glycine residue.However,the role of this myristoylation in the EV71 life cycle remains largely unknown.To investigate thi...The Enterovirus 71(EV71)VP4 is co-translationally linked to myristic acid at its amino-terminal glycine residue.However,the role of this myristoylation in the EV71 life cycle remains largely unknown.To investigate this issue,we developed a myristoylation-deficient virus and reporter(luciferase)pseudovirus with a Gly-to-Ala mutation(G2A)on EV71 VP4.When transfecting the EV71-G2 A genome encoding plasmid in cells,the loss of myristoylation on VP4 did not affect the expression of viral proteins and the virus morphology,however,it did significantly influence viral infectivity.Further,in myristoylation-deficient reporter pseudovirus-infected cells,the luciferase activity and viral genome RNA decreased significantly as compared to that of wild type virus;however,cytopathic effect and viral capsid proteins were not detected in myristoylation-deficient virus-infected cells.Also,although myristoylation-deficient viral RNA and proteins were detected in the second blind passage of infection,they were much fewer in number compared to that of the wild type virus.The replication of genomic RNA and negative-strand viral RNA were both blocked in myristoylation-deficient viruses,suggesting that myristoylation affects viral genome RNA release from capsid to cytoplasm.Besides,loss of myristoylation on VP4 altered the distribution of VP4-green fluorescent protein protein,which disappeared from the membrane structure fraction.Finally,a liposome leakage assay showed that EV71 myristoylation mediates the permeability of the model membrane.Hence,the amino-terminal myristoylation of VP4 is pivotal to EV71 infection and capsidmembrane structure interaction.This study provides novel molecular mechanisms regarding EV71 infection and potential molecular targets for antiviral drug design.展开更多
基金support was provided by the National Natural Science Foundation of China(81572052 and 82102473)Changzhou science and technology support plan(CE20225036,CJ20210141)Young Talent Development Plan of Changzhou Health Commission(2020-233).
文摘TANK-binding kinase 1(TBK1)is an essential protein kinase for activation of interferon regulatory factor 3(IRF3)and induction of the type I interferons(IFN-I).Although the biochemical regulation of TBK1 activation has been studied,little is known about how enterovirus 71(EV71)employs the deubiquitinases(DUBs)to regulate TBK1 activation for viral immune evasion.Here,we found that EV71 infection upregulated the expression of ubiquitinspecific protease 24(USP24).Further studies revealed that USP24 physically interacted with TBK1,and can reduce K63-linked polyubiquitination of TBK1.Knockdown of USP24 upregulated TBK1 K63-linked polyubiquitination,promoted the phosphorylation and nuclear translocation of IRF3,and in turn improved IFN-I production during EV71 infection.As a consequence,USP24 knockdown dramatically inhibited EV71 infection.This study revealed USP24 as a novel regulator of TBK1 activation,which promotes the understanding of immune evasion mechanisms of EV71 and could provide a potential strategy for treatment of EV71 infection.
基金supported by the National Natural Science Foundation of China(Grant No.31770184)
文摘The Enterovirus 71(EV71)VP4 is co-translationally linked to myristic acid at its amino-terminal glycine residue.However,the role of this myristoylation in the EV71 life cycle remains largely unknown.To investigate this issue,we developed a myristoylation-deficient virus and reporter(luciferase)pseudovirus with a Gly-to-Ala mutation(G2A)on EV71 VP4.When transfecting the EV71-G2 A genome encoding plasmid in cells,the loss of myristoylation on VP4 did not affect the expression of viral proteins and the virus morphology,however,it did significantly influence viral infectivity.Further,in myristoylation-deficient reporter pseudovirus-infected cells,the luciferase activity and viral genome RNA decreased significantly as compared to that of wild type virus;however,cytopathic effect and viral capsid proteins were not detected in myristoylation-deficient virus-infected cells.Also,although myristoylation-deficient viral RNA and proteins were detected in the second blind passage of infection,they were much fewer in number compared to that of the wild type virus.The replication of genomic RNA and negative-strand viral RNA were both blocked in myristoylation-deficient viruses,suggesting that myristoylation affects viral genome RNA release from capsid to cytoplasm.Besides,loss of myristoylation on VP4 altered the distribution of VP4-green fluorescent protein protein,which disappeared from the membrane structure fraction.Finally,a liposome leakage assay showed that EV71 myristoylation mediates the permeability of the model membrane.Hence,the amino-terminal myristoylation of VP4 is pivotal to EV71 infection and capsidmembrane structure interaction.This study provides novel molecular mechanisms regarding EV71 infection and potential molecular targets for antiviral drug design.
