Background:NOD-like receptor family CARD domain containing 3(NLRC3)plays an important role in both innate and adaptive immunity.This study was to explore the function and related mechanisms of NLRC3 in a hypoxia/reoxy...Background:NOD-like receptor family CARD domain containing 3(NLRC3)plays an important role in both innate and adaptive immunity.This study was to explore the function and related mechanisms of NLRC3 in a hypoxia/reoxygenation(H/R)-induced inflammatory response in RAW264.7 cells.Methods:Liver ischemia-reperfusion(I/R)model in mice and H/R model in RAW264.7 cells were constructed.Western blotting was used to determine the protein expression level of NLRC3 in liver tissue and NLRC3,TRAF6,p–p65,p65,IκB–α,and the K63-linked ubiquitination level of TRAF6 in cells.The immunofluorescence assay was performed to evaluate the nuclear level of the NF–κB(p65).ELISA was conducted to measure the content of IL–1βin serum and cell supernatant.The interaction between NLRC3 and TRAF6 in cells was analyzed by the Co-IP assay.Results:The NLRC3 protein level in liver tissue was decreased with the prolongation of reperfusion time(P<0.05).The expression of NLRC3 and IκB–αprotein in RAW264.7 was decreased gradually,while the expression of p–p65 and TRAF6 proteins and K63-linked ubiquitination of TRAF6 were increased gradually with the prolongation of reoxgenation time(P<0.05).The Co-IP assay revealed that NLRC3 and TRAF6 can bind to each other directly.However,NLRC3 had no effect on the expression of TRAF6 protein.The ubiquitination test results showed that the K63-linked ubiquitination level of TRAF6 in H/R+Lv–NLRC3 group was significantly lower than that in the H/R+negative control(NC)group(P<0.05).Moreover,the activation of NF–κB in H/R+Lv–NLRC3 group was inhibited compared with that in the H/R+NC group,and the level of the inflammatory factor IL–1βin the cell culture supernatant was also decreased accordingly(P<0.05).Conclusions:NLRC3 might alleviate H/R-induced inflammation in RAW264.7 cells by inhibiting K63-linked ubiquitination of TRAF6.展开更多
目的筛选K48聚泛素链在肿瘤坏死因子受体相关因子2(tumor necrosis factor receptor-associated facto r 2,T RA F2)上的主要修饰位点。方法比较不同物种间的T RA F2氨基酸序列,选出人T RA F2上保守率在90%以上的赖氨酸。构建人野生型TR...目的筛选K48聚泛素链在肿瘤坏死因子受体相关因子2(tumor necrosis factor receptor-associated facto r 2,T RA F2)上的主要修饰位点。方法比较不同物种间的T RA F2氨基酸序列,选出人T RA F2上保守率在90%以上的赖氨酸。构建人野生型TRAF2的表达载体及保守赖氨酸突变为精氨酸的突变表达载体。将不同的TRAF2表达载体与NF-κB荧光素酶报告基因表达载体共转至293FT细胞中,通过荧光素酶检测NF-κB激活情况。结果人TRAF2上共有8个保守率在90%以上的赖氨酸,酶切及测序结果证明本研究成功构建TRAF2野生型和突变型表达载体。NF-κB荧光素酶报告基因检测证明TRAF2-K320可能是K48聚泛素链的主要修饰位点。结论 TRAF2-K320位点对TRAF2介导的NF-κB激活具有负向调控作用。展开更多
K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In ...K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In the regional trial of Hubei Province in 1991, its yield was 4.4% higher than that of the CK Weiyou 48-2, being significant at 0.05 level. In the same year, in another regional trial of Sichuan Province, its yield was 8.9% higher than that of the CK Weiyou 48-2, being significant at 0.01 level. It has the highest yield among all tested varieties in both provincial trials. It has shown good grain quality with 60% head rice recovery and moderate resistance to rice blast.展开更多
The adaptor molecule MAVS forms prion-like aggregates to govern the RIG-I-like receptor(RLR)signaling cascade.Lys63(K63)-linked polyubiquitination is critical for MAVS aggregation,yet the underlying mechanism and the ...The adaptor molecule MAVS forms prion-like aggregates to govern the RIG-I-like receptor(RLR)signaling cascade.Lys63(K63)-linked polyubiquitination is critical for MAVS aggregation,yet the underlying mechanism and the corresponding E3 ligases and deubiquitinating enzymes(DUBs)remain elusive.Here,we found that the K63-linked polyubiquitin chains loaded on MAVS can be directly recognized by RIG-I to initiate RIG-I-mediated MAVS aggregation with the prerequisite of the CARDRIG-I-CARDMAVS interaction.Interestingly,many K63-linked polyubiquitin chains attach to MAVS via an unanchored linkage.We identified Ube2N as a major ubiquitin-conjugating enzyme for MAVS and revealed that Ube2N cooperates with the E3 ligase Riplet and TRIM31 to promote the unanchored K63-linked polyubiquitination of MAVS.In addition,we identified USP10 as a direct DUB that removes unanchored K63-linked polyubiquitin chains from MAVS.Consistently,USP10 attenuates RIG-I-mediated MAVS aggregation and the production of type I interferon.Mice with a deficiency in USP10 show more potent resistance to RNA virus infection.Our work proposes a previously unknown mechanism for the activation of the RLR signaling cascade triggered by MAVS-attached unanchored K63-linked polyubiquitin chains and establishes the DUB USP10 and the E2:E3 pair Ube2N-Riplet/TRIM31 as a specific regulatory system for the unanchored K63-linked ubiquitination and aggregation of MAVS upon viral infection.展开更多
Poly(ADP-ribosyl)ation(PARylation)is a posttranslational modification reversibly catalyzed by poly(ADP-ribose)polymerases(PARPs)and poly(ADP-ribose)glycohydrolases(PARGs)and plays a key role in multi-ple cellular proc...Poly(ADP-ribosyl)ation(PARylation)is a posttranslational modification reversibly catalyzed by poly(ADP-ribose)polymerases(PARPs)and poly(ADP-ribose)glycohydrolases(PARGs)and plays a key role in multi-ple cellular processes.The molecular mechanisms by which PARylation regulates innate immunity remain largely unknown in eukaryotes.Here we show that Arabidopsis UBC13A and UBC13B,the major drivers of lysine 63(K63)-linked polyubiquitination,directly interact with PARPs/PARGs.Activation of pathogen-associated molecular pattern(PAMP)-triggered immunity promotes these interactions and enhances PARylation of UBC13.Both parp1 parp2 and ubc13a ubc13b mutants are compromised in immune responses with increased accumulation of total pathogenesis-related(PR)proteins but decreased accu-mulation of secreted PR proteins.Protein disulfide-isomerases(PDIs),essential components of endo-plasmic reticulum quality control(ERQC)that ensure proper folding and maturation of proteins destined for secretion,complex with PARPs/PARGs and are PARylated upon PAMP perception.Significantly,PARylation of UBC13 regulates K63-linked ubiquitination of PDIs,which may further promote their disulfide isomerase activities for correct protein folding and subsequent secretion.Taken together,these results indicate that plant immunity is coordinately regulated by PARylation and K63-linked ubiquitination.展开更多
Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by ...Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings.Here,we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I.The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A.In response to ligands,IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250,opening the middle loop(Leu130-Cys141) to the RING domain of MEX3A through the conformational changes of βarr2.The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I.The assay of the mutants βarr2Y64Aand βarr2Y250Afurther confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A.The truncated-βarr2 and the peptide ATQAIRIF,which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes,thus blocking the IGF-1R-triggered RIG-I degradation.Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway.Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I.In summary,we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.展开更多
Inflammasomes are essential components of the innate immune system and its defense against infections,whereas the dysregulation of inflammasome activation has a detrimental effect on human health.The activation of inf...Inflammasomes are essential components of the innate immune system and its defense against infections,whereas the dysregulation of inflammasome activation has a detrimental effect on human health.The activation of inflammasomes is subjected to tight regulation to maintain immune homeostasis,yet the underlying mechanism remains elusive.Here,we identify USP3 as a direct deubiquitinating enzyme(DUB)for ASC,the central adapter mediating the assembly and activation of most inflammasomes.USP3 removes the K48-linked ubiquitination on ASC and strengthens its stability by blocking proteasomal degradation.Additionally,USP3 promotes inflammasome activation,and this function was confirmed in mouse models of aluminum(Alum)-induced peritonitis,F.novicida infection and flagellin-induced pneumonia in vivo.Our work unveils that USP3 functions as a key regulator of ASC ubiquitination and maintains the physiological role of ASC in mediating inflammasome activation,and we propose a new mechanism by which the ubiquitination of ASC regulates inflammasome activation.展开更多
基金This study was supported by grants from the National Natural Science Foundation of China(81873592)the graduate tutor team construction project of Chongqing Municipal Education Commission Foundation(dstd201801).
文摘Background:NOD-like receptor family CARD domain containing 3(NLRC3)plays an important role in both innate and adaptive immunity.This study was to explore the function and related mechanisms of NLRC3 in a hypoxia/reoxygenation(H/R)-induced inflammatory response in RAW264.7 cells.Methods:Liver ischemia-reperfusion(I/R)model in mice and H/R model in RAW264.7 cells were constructed.Western blotting was used to determine the protein expression level of NLRC3 in liver tissue and NLRC3,TRAF6,p–p65,p65,IκB–α,and the K63-linked ubiquitination level of TRAF6 in cells.The immunofluorescence assay was performed to evaluate the nuclear level of the NF–κB(p65).ELISA was conducted to measure the content of IL–1βin serum and cell supernatant.The interaction between NLRC3 and TRAF6 in cells was analyzed by the Co-IP assay.Results:The NLRC3 protein level in liver tissue was decreased with the prolongation of reperfusion time(P<0.05).The expression of NLRC3 and IκB–αprotein in RAW264.7 was decreased gradually,while the expression of p–p65 and TRAF6 proteins and K63-linked ubiquitination of TRAF6 were increased gradually with the prolongation of reoxgenation time(P<0.05).The Co-IP assay revealed that NLRC3 and TRAF6 can bind to each other directly.However,NLRC3 had no effect on the expression of TRAF6 protein.The ubiquitination test results showed that the K63-linked ubiquitination level of TRAF6 in H/R+Lv–NLRC3 group was significantly lower than that in the H/R+negative control(NC)group(P<0.05).Moreover,the activation of NF–κB in H/R+Lv–NLRC3 group was inhibited compared with that in the H/R+NC group,and the level of the inflammatory factor IL–1βin the cell culture supernatant was also decreased accordingly(P<0.05).Conclusions:NLRC3 might alleviate H/R-induced inflammation in RAW264.7 cells by inhibiting K63-linked ubiquitination of TRAF6.
文摘目的筛选K48聚泛素链在肿瘤坏死因子受体相关因子2(tumor necrosis factor receptor-associated facto r 2,T RA F2)上的主要修饰位点。方法比较不同物种间的T RA F2氨基酸序列,选出人T RA F2上保守率在90%以上的赖氨酸。构建人野生型TRAF2的表达载体及保守赖氨酸突变为精氨酸的突变表达载体。将不同的TRAF2表达载体与NF-κB荧光素酶报告基因表达载体共转至293FT细胞中,通过荧光素酶检测NF-κB激活情况。结果人TRAF2上共有8个保守率在90%以上的赖氨酸,酶切及测序结果证明本研究成功构建TRAF2野生型和突变型表达载体。NF-κB荧光素酶报告基因检测证明TRAF2-K320可能是K48聚泛素链的主要修饰位点。结论 TRAF2-K320位点对TRAF2介导的NF-κB激活具有负向调控作用。
文摘K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In the regional trial of Hubei Province in 1991, its yield was 4.4% higher than that of the CK Weiyou 48-2, being significant at 0.05 level. In the same year, in another regional trial of Sichuan Province, its yield was 8.9% higher than that of the CK Weiyou 48-2, being significant at 0.01 level. It has the highest yield among all tested varieties in both provincial trials. It has shown good grain quality with 60% head rice recovery and moderate resistance to rice blast.
基金supported by grants from the National Natural Science Foundation of China(31730026,81930039,32000633)National Key Research and Development Program(2021YFC2300603),Natural Science Foundation of Shandong Province(ZR2020QH136)China Postdoctoral Science Foundation(2020M682187),and Postdoctoral Innovation Project of Shandong Province(202002012).
文摘The adaptor molecule MAVS forms prion-like aggregates to govern the RIG-I-like receptor(RLR)signaling cascade.Lys63(K63)-linked polyubiquitination is critical for MAVS aggregation,yet the underlying mechanism and the corresponding E3 ligases and deubiquitinating enzymes(DUBs)remain elusive.Here,we found that the K63-linked polyubiquitin chains loaded on MAVS can be directly recognized by RIG-I to initiate RIG-I-mediated MAVS aggregation with the prerequisite of the CARDRIG-I-CARDMAVS interaction.Interestingly,many K63-linked polyubiquitin chains attach to MAVS via an unanchored linkage.We identified Ube2N as a major ubiquitin-conjugating enzyme for MAVS and revealed that Ube2N cooperates with the E3 ligase Riplet and TRIM31 to promote the unanchored K63-linked polyubiquitination of MAVS.In addition,we identified USP10 as a direct DUB that removes unanchored K63-linked polyubiquitin chains from MAVS.Consistently,USP10 attenuates RIG-I-mediated MAVS aggregation and the production of type I interferon.Mice with a deficiency in USP10 show more potent resistance to RNA virus infection.Our work proposes a previously unknown mechanism for the activation of the RLR signaling cascade triggered by MAVS-attached unanchored K63-linked polyubiquitin chains and establishes the DUB USP10 and the E2:E3 pair Ube2N-Riplet/TRIM31 as a specific regulatory system for the unanchored K63-linked ubiquitination and aggregation of MAVS upon viral infection.
基金supported by a start-up fund from Texas A&M AgriLife Research to J.S.a grant from the National Science Foundation(IOS-1951094)to P.H.and J.S.
文摘Poly(ADP-ribosyl)ation(PARylation)is a posttranslational modification reversibly catalyzed by poly(ADP-ribose)polymerases(PARPs)and poly(ADP-ribose)glycohydrolases(PARGs)and plays a key role in multi-ple cellular processes.The molecular mechanisms by which PARylation regulates innate immunity remain largely unknown in eukaryotes.Here we show that Arabidopsis UBC13A and UBC13B,the major drivers of lysine 63(K63)-linked polyubiquitination,directly interact with PARPs/PARGs.Activation of pathogen-associated molecular pattern(PAMP)-triggered immunity promotes these interactions and enhances PARylation of UBC13.Both parp1 parp2 and ubc13a ubc13b mutants are compromised in immune responses with increased accumulation of total pathogenesis-related(PR)proteins but decreased accu-mulation of secreted PR proteins.Protein disulfide-isomerases(PDIs),essential components of endo-plasmic reticulum quality control(ERQC)that ensure proper folding and maturation of proteins destined for secretion,complex with PARPs/PARGs and are PARylated upon PAMP perception.Significantly,PARylation of UBC13 regulates K63-linked ubiquitination of PDIs,which may further promote their disulfide isomerase activities for correct protein folding and subsequent secretion.Taken together,these results indicate that plant immunity is coordinately regulated by PARylation and K63-linked ubiquitination.
基金supported by Beijing Natural Science Foundation(7222253,China)National Natural Science Foundation of China(81973350/82173841)supported by Beijing Natural Science Foundation(7212149,China)。
文摘Insulin-like growth factor-1 receptor(IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers.However,targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings.Here,we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I.The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A.In response to ligands,IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250,opening the middle loop(Leu130-Cys141) to the RING domain of MEX3A through the conformational changes of βarr2.The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I.The assay of the mutants βarr2Y64Aand βarr2Y250Afurther confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A.The truncated-βarr2 and the peptide ATQAIRIF,which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes,thus blocking the IGF-1R-triggered RIG-I degradation.Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway.Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I.In summary,we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.
基金This work was supported by grants from the National Key Research and Development Program(2021YFC2300603),the National Natural Science Foundation of China(32000633,31730026,81930039)the Natural Science Foundation of Shandong Province(ZR2020QH136)+1 种基金the China Postdoctoral Science Foundation(2020M682187)the Postdoctoral Innovation Project of Shandong Province(202002012).
文摘Inflammasomes are essential components of the innate immune system and its defense against infections,whereas the dysregulation of inflammasome activation has a detrimental effect on human health.The activation of inflammasomes is subjected to tight regulation to maintain immune homeostasis,yet the underlying mechanism remains elusive.Here,we identify USP3 as a direct deubiquitinating enzyme(DUB)for ASC,the central adapter mediating the assembly and activation of most inflammasomes.USP3 removes the K48-linked ubiquitination on ASC and strengthens its stability by blocking proteasomal degradation.Additionally,USP3 promotes inflammasome activation,and this function was confirmed in mouse models of aluminum(Alum)-induced peritonitis,F.novicida infection and flagellin-induced pneumonia in vivo.Our work unveils that USP3 functions as a key regulator of ASC ubiquitination and maintains the physiological role of ASC in mediating inflammasome activation,and we propose a new mechanism by which the ubiquitination of ASC regulates inflammasome activation.
