Ring finger protein 122(RNF122),an E3 ubiquitin ligase,orchestrates antiviral immune responses in mammals by targeting retinoic acid-inducible gene 1 and melanoma differentiation-associated gene 5 for ubiquitination.H...Ring finger protein 122(RNF122),an E3 ubiquitin ligase,orchestrates antiviral immune responses in mammals by targeting retinoic acid-inducible gene 1 and melanoma differentiation-associated gene 5 for ubiquitination.However,its functional relevance in teleosts has yet to be clearly defined,particularly regarding the identification of substrate-specific regulatory sites.This study characterized RNF122 from mandarin fish(Siniperca chuatsi),termed scRNF122,and investigated its regulatory impact on stimulator of interferon genes(STING)-mediated antiviral signaling.Results showed that scRNF122 expression was up-regulated in response to mandarin fish ranavirus(MRV)infection,and its overexpression suppressed scSTING-mediated interferon(IFN)production and enhanced MRV replication.Co-immunoprecipitation confirmed a direct interaction between scRNF122 and scSTING.Functional assays demonstrated that scRNF122 facilitated scSTING degradation through the ubiquitin-proteasome pathway,a process impeded by MG132 treatment.Ubiquitination analyses of various scSTING mutants revealed that scRNF122 catalyzed scSTING ubiquitination at K95,K117,and K155 residues.Moreover,scRNF122 significantly impaired scSTING-dependent antiviral responses by engaging negative regulatory elements within the signaling cascade.Overall,scRNF122 was identified as a negative modulator of STING-mediated IFN signaling in mandarin fish,diminishing STING-dependent antiviral activity and promoting its degradation via the ubiquitin-proteasome pathway at lysine residues K95,K117,and K155.These findings provide mechanistic insight into the post-translational control of STING in teleosts and establish a foundation for future investigations into antiviral immune regulation.展开更多
基金supported by the National Key Research and Development Program of China(2022YFE0203900,2024YFD2401101)China Agriculture Research System(CARS-46)+1 种基金National Natural Science Foundation of China(32473201)Guangdong S&T Program(2022B1111030001,2024B1212040007)。
文摘Ring finger protein 122(RNF122),an E3 ubiquitin ligase,orchestrates antiviral immune responses in mammals by targeting retinoic acid-inducible gene 1 and melanoma differentiation-associated gene 5 for ubiquitination.However,its functional relevance in teleosts has yet to be clearly defined,particularly regarding the identification of substrate-specific regulatory sites.This study characterized RNF122 from mandarin fish(Siniperca chuatsi),termed scRNF122,and investigated its regulatory impact on stimulator of interferon genes(STING)-mediated antiviral signaling.Results showed that scRNF122 expression was up-regulated in response to mandarin fish ranavirus(MRV)infection,and its overexpression suppressed scSTING-mediated interferon(IFN)production and enhanced MRV replication.Co-immunoprecipitation confirmed a direct interaction between scRNF122 and scSTING.Functional assays demonstrated that scRNF122 facilitated scSTING degradation through the ubiquitin-proteasome pathway,a process impeded by MG132 treatment.Ubiquitination analyses of various scSTING mutants revealed that scRNF122 catalyzed scSTING ubiquitination at K95,K117,and K155 residues.Moreover,scRNF122 significantly impaired scSTING-dependent antiviral responses by engaging negative regulatory elements within the signaling cascade.Overall,scRNF122 was identified as a negative modulator of STING-mediated IFN signaling in mandarin fish,diminishing STING-dependent antiviral activity and promoting its degradation via the ubiquitin-proteasome pathway at lysine residues K95,K117,and K155.These findings provide mechanistic insight into the post-translational control of STING in teleosts and establish a foundation for future investigations into antiviral immune regulation.
