The ubiquitin （Ub）-conjugating enzyme, Ubc13, has been known to be involved in error-free DNA damage tolerance （or post-replication repair） via catalyzing Lys63-linked polyubiquitin chains formation together with ...The ubiquitin （Ub）-conjugating enzyme, Ubc13, has been known to be involved in error-free DNA damage tolerance （or post-replication repair） via catalyzing Lys63-linked polyubiquitin chains formation together with a Ubc variant. However, its functions remain largely unknown in plant species, especial y in monocotyledons. In this study, we cloned a Ub-conjugating enzyme, OsUbc13, that shares the conserved domain of Ubc with AtUBC13B in Oryza sativa L., which encodes a protein of 153 amino acids; the deduced sequence shares high similarities with other homologs. Real-time quantitative polymerase chain reaction （PCR） indicated that OsUbc13 transcripts could be de-tected in al tissues examined, and the expression level was higher in palea, pistil, stamen, and leaf, and lower in root, stem, and lemma;the expression of OsUbc13 was induced by low temperature, methylmethane sulfate （MMS）, and H2O2, but repressed by mannitol, abscisic acid （ABA）, and NaCl. OsUbc13 was probably localized in the plasma and nuclear membranes. About 20 proteins, which are responsible for the positive yeast two-hybrid interaction of OsUbc13, were identified. These include the confirmed OsVDAC （correlated with apoptosis）, OsMADS1 （important for development of floral organs）, OsB22EL8 （related to reactive oxygen species （ROS） scavenging and DNA protection）, and OsCROC-1 （required for formation of Lys63 polyubiquitylation and error-free DNA damage tolerance）. The molecular characterization provides a foundation for the functional study of OsUbc13.展开更多
Nowadays potential preclinical drugs for the treatment of nonalcoholic steatohepatitis(NASH)have failed to achieve expected therapeutic efficacy because the pathogenic mechanisms are underestimated.Inactive rhomboid p...Nowadays potential preclinical drugs for the treatment of nonalcoholic steatohepatitis(NASH)have failed to achieve expected therapeutic efficacy because the pathogenic mechanisms are underestimated.Inactive rhomboid protein 2(IRHOM2),a promising target for treatment of inflammation-related diseases,contributes to deregulated hepatocyte metabolism-associated nonalcoholic steatohepatitis(NASH)progression.However,the molecular mechanism underlying Irhom2 regulation is still not completely understood.In this work,we identify the ubiquitin-specific protease 13(USP13)as a critical and novel endogenous blocker of IRHOM2,and we also indicate that USP13 is an IRHOM2-interacting protein that catalyzes deubiquitination of Irhom2 in hepatocytes.Hepatocyte-specific loss of the Usp13 disrupts liver metabolic homeostasis,followed by glycometabolic disorder,lipid deposition,increased inflammation,and markedly promotes NASH development.Conversely,transgenic mice with Usp13 overexpression,lentivirus(LV)-or adeno-associated virus(AAV)-driven Usp13 gene therapeutics mitigates NASH in 3 models of rodent.Mechanistically,in response to metabolic stresses,USP13 directly interacts with IRHOM2 and removes its K63-linked ubiquitination induced by ubiquitin-conjugating enzyme E2N(UBC13),a ubiquitin E2 conjugating enzyme,and thus prevents its activation of downstream cascade pathway.USP13 is a potential treatment target for NASH therapy by targeting the Irhom2 signaling pathway.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
基金Project supported by the National High-Tech R&D Program(863)of China(No.2006AA10Z159)the National Natural Science Foundation of China(No.30871502)
文摘The ubiquitin （Ub）-conjugating enzyme, Ubc13, has been known to be involved in error-free DNA damage tolerance （or post-replication repair） via catalyzing Lys63-linked polyubiquitin chains formation together with a Ubc variant. However, its functions remain largely unknown in plant species, especial y in monocotyledons. In this study, we cloned a Ub-conjugating enzyme, OsUbc13, that shares the conserved domain of Ubc with AtUBC13B in Oryza sativa L., which encodes a protein of 153 amino acids; the deduced sequence shares high similarities with other homologs. Real-time quantitative polymerase chain reaction （PCR） indicated that OsUbc13 transcripts could be de-tected in al tissues examined, and the expression level was higher in palea, pistil, stamen, and leaf, and lower in root, stem, and lemma;the expression of OsUbc13 was induced by low temperature, methylmethane sulfate （MMS）, and H2O2, but repressed by mannitol, abscisic acid （ABA）, and NaCl. OsUbc13 was probably localized in the plasma and nuclear membranes. About 20 proteins, which are responsible for the positive yeast two-hybrid interaction of OsUbc13, were identified. These include the confirmed OsVDAC （correlated with apoptosis）, OsMADS1 （important for development of floral organs）, OsB22EL8 （related to reactive oxygen species （ROS） scavenging and DNA protection）, and OsCROC-1 （required for formation of Lys63 polyubiquitylation and error-free DNA damage tolerance）. The molecular characterization provides a foundation for the functional study of OsUbc13.
基金supported by National Natural Science Foundation of China(NSFC Grant Nos.81703527 and 82200652)Chongqing Research Program of Basic Research and Frontier Technology(Grant Nos.cstc2017jcyjAX0356,cstc2018jcyjA3686,cstc2018jcyjAX0784,cstc2018jcyjA1472,cstc2018jcyjAX0811,cstc2018jcyjA3533,and KJZD-M201801601,China)+4 种基金School-level Research Program of Chongqing University of Education(Grant Nos.KY201710B and 17GZKP01,China)Advanced Programs of Post-doctor of Chongqing(Grant No.2017LY39,China)Science and Technology Research Program of Chongqing Education Commission of China(Grant Nos.KJQN201901608,KJQN201901615,KJ1601402,and KJZDK202001603)Children's Research Institute of National Center for Schooling Development Programme and Chongqing University of Education(Grant No.CSDP19FSO1108,China)Chongqing Professional Talents Plan for Innovation and Entrepreneurship Demonstration Team(CQCY201903258,China).
文摘Nowadays potential preclinical drugs for the treatment of nonalcoholic steatohepatitis(NASH)have failed to achieve expected therapeutic efficacy because the pathogenic mechanisms are underestimated.Inactive rhomboid protein 2(IRHOM2),a promising target for treatment of inflammation-related diseases,contributes to deregulated hepatocyte metabolism-associated nonalcoholic steatohepatitis(NASH)progression.However,the molecular mechanism underlying Irhom2 regulation is still not completely understood.In this work,we identify the ubiquitin-specific protease 13(USP13)as a critical and novel endogenous blocker of IRHOM2,and we also indicate that USP13 is an IRHOM2-interacting protein that catalyzes deubiquitination of Irhom2 in hepatocytes.Hepatocyte-specific loss of the Usp13 disrupts liver metabolic homeostasis,followed by glycometabolic disorder,lipid deposition,increased inflammation,and markedly promotes NASH development.Conversely,transgenic mice with Usp13 overexpression,lentivirus(LV)-or adeno-associated virus(AAV)-driven Usp13 gene therapeutics mitigates NASH in 3 models of rodent.Mechanistically,in response to metabolic stresses,USP13 directly interacts with IRHOM2 and removes its K63-linked ubiquitination induced by ubiquitin-conjugating enzyme E2N(UBC13),a ubiquitin E2 conjugating enzyme,and thus prevents its activation of downstream cascade pathway.USP13 is a potential treatment target for NASH therapy by targeting the Irhom2 signaling pathway.
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.
