Protein degradation through the ubiquitin-proteasome system is the major pathway of non-lysosomal proteolysis of intracellular proteins. It plays important roles in a variety of fundamental cellular processes such as ...Protein degradation through the ubiquitin-proteasome system is the major pathway of non-lysosomal proteolysis of intracellular proteins. It plays important roles in a variety of fundamental cellular processes such as regulation of cell cycle progression, division, development and differentiation, apoptosis, cell trafficking, and modulation of the immune and inflammatory responses. The central element of this system is the covalent linkage of ubiquitin to targeted proteins, which are then recognized by the 26S proteasome, an adenosine triphosphate-dependent, multi-catalytic protease. Damaged, oxidized, or misfolded proteins as well as regulatory proteins that control many critical cellular functions are among the targets of this degradation process. Aberration of this system leads to the dysregulation of cellular homeostasis and the development of multiple diseases. In this review, we described the basic biochemistry and molecular biology of the ubiquitin-proteasome system, and its complex role in the development of inflammatory and autoimmune diseases. In addition, therapies and potential therapeutic targets related to the ubiquitin-proteasome system are discussed as well.展开更多
Abnormal protein expression or activities are associated with many diseases,especially cancer.Therefore,down-regulating the proteins involved in cancer cell survival proved to be an effective strategy for cancer treat...Abnormal protein expression or activities are associated with many diseases,especially cancer.Therefore,down-regulating the proteins involved in cancer cell survival proved to be an effective strategy for cancer treatment—a number of drugs based on proteolysis-targeting chimaera(PROTAC)mechanism have demonstrated clinical efficacy.Recent progress in the PROTAC strategy includes identification of the structure of the first ternary eutectic complex,extra-terminal domain-4-PROTAC-VonHippel-Lindau(BRD4-PROTAC-VHL),and PROTAC ARV-110 has entered clinical trials for the treatment of prostate cancer in 2019.These discoveries strongly proved the value of the PROTAC strategy.In this review,we summarize recent meaningful research of PROTACs,including the molecular design and optimization strategy as well as clinical application of candidate molecules.We hope to provide useful insights for rational design of PROTACs.展开更多
In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review ...In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review highlights the recent developments In the identification of GA signaling pathway components, the discovery of GA-Induced destructlon of GA signaling repressor （DELLA protein）, and the possible mechanism underlying the regulation of GA- responsive gene expression in rice.展开更多
The endoplasmic reticulum,chloroplasts,and mitochondria are major plant organelles for protein synthesis,photosynthesis,metabolism,and energy production.Protein homeostasis in these organelles,maintained by a balance ...The endoplasmic reticulum,chloroplasts,and mitochondria are major plant organelles for protein synthesis,photosynthesis,metabolism,and energy production.Protein homeostasis in these organelles,maintained by a balance between protein synthesis and degradation,is essential for cell functions during plant growth,development,and stress resistance.Nucleus-encoded chloroplast-and mitochondrion-targeted proteins and ER-resident proteins are imported from the cytosol and undergo modification and maturation within their respective organelles.Protein folding is an error-prone process that is influenced by both developmental signals and environmental cues;a number of mechanisms have evolved to ensure efficient import and proper folding and maturation of proteins in plant organelles.Misfolded or damaged proteins with nonnative conformations are subject to degradation via complementary or competing pathways:intraorganelle proteases,the organelle-associated ubiquitin-proteasome system,and the selective autophagy of partial or entire organelles.When proteins in nonnative conformations accumulate,the organellespecific unfolded protein response operates to restore protein homeostasis by reducing protein folding demand,increasing protein folding capacity,and enhancing components involved in proteasome-associated protein degradation and autophagy.This review summarizes recent progress on the understanding of protein quality control in the ER,chloroplasts,and mitochondria in plants,with a focus on common mechanisms shared by these organelles during protein homeostasis.展开更多
Senescence-related protease may play an important role in leaf senescence. By improved SDS-Gela-tin-PAGE assay, a 63 ku senescence-related protease (63 SRP) in coriander leaves was identified. Activity of 63 SRP was i...Senescence-related protease may play an important role in leaf senescence. By improved SDS-Gela-tin-PAGE assay, a 63 ku senescence-related protease (63 SRP) in coriander leaves was identified. Activity of 63 SRP was increased in parallel to the advance of coriander leaf senescence, and inhibited by treating the leaf with gibberellic acid, and enhanced by ethylene treatment. The 63 SRP was suggested to be a serine protease based on the fact that its activity was inhibited by the protease inhibitor PMSF. The optimal temperature for the activity of the 70 ku protease was 50°C. The maximal activity was observed at pH 6-9, some activity could be observed on the gel slices incubated at pH 5 or 11. The 63 SRP was partly purified by the way of ammonium sulfate precipitation and then gel slicing after gel elec-trophoresis.展开更多
Poly(ethylene terephthalate)hydrolase(PETase)from Ideonella sakaiensis exhibits a strong ability to degrade poly(ethylene terephthalate)(PET)at room temperature,and is thus regarded as a potential tool to solve the is...Poly(ethylene terephthalate)hydrolase(PETase)from Ideonella sakaiensis exhibits a strong ability to degrade poly(ethylene terephthalate)(PET)at room temperature,and is thus regarded as a potential tool to solve the issue of polyester plastic pollution.Therefore,we explored the interaction between PETase and the substrate(a dimer of the PET monomer ethylene terephthalate,2PET),using a model of PETase and its substrate.In this study,we focused on six key residues around the substrate-binding groove in order to create novel high-efficiency PETase mutants through protein engineering.These PETase mutants were designed and tested.The enzymatic activities of the R61A,L88F,and I179F mutants,which were obtained with a rapid cell-free screening system,exhibited 1.4 fold,2.1 fold,and 2.5 fold increases,respectively,in comparison with wild-type PETase.The I179F mutant showed the highest activity,with the degradation rate of a PET film reaching 22.5 mg perμmol·L^-1 PETase per day.Thus,this study has created enhanced artificial PETase enzymes through the rational protein engineering of key hydrophobic sites,and has further illustrated the potential of biodegradable plastics.展开更多
Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that underg...Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.展开更多
In flowering plants, self-incompatibility （SI） serves as an important intraspecific reproductive barrier to promote outbreeding. In species from the Solanaceae, Plantaginaceae and Rosaceae, S-RNase and SLF （S-locus...In flowering plants, self-incompatibility （SI） serves as an important intraspecific reproductive barrier to promote outbreeding. In species from the Solanaceae, Plantaginaceae and Rosaceae, S-RNase and SLF （S-locus F-box） proteins have been shown to control the female and male specificity of SI, respectively. However, little is known about structure features of the SLF protein apart from its conserved F-box domain. Here we show that the SLF C-terminal region possesses a novel ubiquitin-binding domain （UBD） structure conserved among the SLF protein family. By using an ex vivo system of Nicotiana benthamiana, we found that the UBD mediates the SLF protein turnover by the ubiquitin-proteasome pathway. Furthermore, we detected that the SLF protein was directly involved in S-RNase degradation. Taken together, our results provide a novel insight into the SLF structure and highlight a potential role of SLF protein stability and degradation in S-RNase-based self-incompatibility.展开更多
文摘Protein degradation through the ubiquitin-proteasome system is the major pathway of non-lysosomal proteolysis of intracellular proteins. It plays important roles in a variety of fundamental cellular processes such as regulation of cell cycle progression, division, development and differentiation, apoptosis, cell trafficking, and modulation of the immune and inflammatory responses. The central element of this system is the covalent linkage of ubiquitin to targeted proteins, which are then recognized by the 26S proteasome, an adenosine triphosphate-dependent, multi-catalytic protease. Damaged, oxidized, or misfolded proteins as well as regulatory proteins that control many critical cellular functions are among the targets of this degradation process. Aberration of this system leads to the dysregulation of cellular homeostasis and the development of multiple diseases. In this review, we described the basic biochemistry and molecular biology of the ubiquitin-proteasome system, and its complex role in the development of inflammatory and autoimmune diseases. In addition, therapies and potential therapeutic targets related to the ubiquitin-proteasome system are discussed as well.
基金the support from grants(Nos.81573281)of National Natural Science Foundation of Chinasupport from Double First-Class initiative Innovation team project of China Pharmaceutical University(Nos.CPU2018GF11 and CPU2018GY34,China).
文摘Abnormal protein expression or activities are associated with many diseases,especially cancer.Therefore,down-regulating the proteins involved in cancer cell survival proved to be an effective strategy for cancer treatment—a number of drugs based on proteolysis-targeting chimaera(PROTAC)mechanism have demonstrated clinical efficacy.Recent progress in the PROTAC strategy includes identification of the structure of the first ternary eutectic complex,extra-terminal domain-4-PROTAC-VonHippel-Lindau(BRD4-PROTAC-VHL),and PROTAC ARV-110 has entered clinical trials for the treatment of prostate cancer in 2019.These discoveries strongly proved the value of the PROTAC strategy.In this review,we summarize recent meaningful research of PROTACs,including the molecular design and optimization strategy as well as clinical application of candidate molecules.We hope to provide useful insights for rational design of PROTACs.
基金Publication of this paper is supported by the National Natural Science Foundation of China （30624808）.
文摘In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review highlights the recent developments In the identification of GA signaling pathway components, the discovery of GA-Induced destructlon of GA signaling repressor （DELLA protein）, and the possible mechanism underlying the regulation of GA- responsive gene expression in rice.
基金Projects associated with protein homeostasis in the Liu Lab are financially supported by grants from the National Natural Science Foundation of China(31625004,31872653,and 31800210)the Zhejiang Provincial Talent Program(2019R52005)the 111 Project(B14027).
文摘The endoplasmic reticulum,chloroplasts,and mitochondria are major plant organelles for protein synthesis,photosynthesis,metabolism,and energy production.Protein homeostasis in these organelles,maintained by a balance between protein synthesis and degradation,is essential for cell functions during plant growth,development,and stress resistance.Nucleus-encoded chloroplast-and mitochondrion-targeted proteins and ER-resident proteins are imported from the cytosol and undergo modification and maturation within their respective organelles.Protein folding is an error-prone process that is influenced by both developmental signals and environmental cues;a number of mechanisms have evolved to ensure efficient import and proper folding and maturation of proteins in plant organelles.Misfolded or damaged proteins with nonnative conformations are subject to degradation via complementary or competing pathways:intraorganelle proteases,the organelle-associated ubiquitin-proteasome system,and the selective autophagy of partial or entire organelles.When proteins in nonnative conformations accumulate,the organellespecific unfolded protein response operates to restore protein homeostasis by reducing protein folding demand,increasing protein folding capacity,and enhancing components involved in proteasome-associated protein degradation and autophagy.This review summarizes recent progress on the understanding of protein quality control in the ER,chloroplasts,and mitochondria in plants,with a focus on common mechanisms shared by these organelles during protein homeostasis.
基金This work was supported by the Joint Sino-Israeli Agricultural Research Fund (Grant No. SIARF2001-04) the National Natural Science Foundation of China (Grant No. 30070535).
文摘Senescence-related protease may play an important role in leaf senescence. By improved SDS-Gela-tin-PAGE assay, a 63 ku senescence-related protease (63 SRP) in coriander leaves was identified. Activity of 63 SRP was increased in parallel to the advance of coriander leaf senescence, and inhibited by treating the leaf with gibberellic acid, and enhanced by ethylene treatment. The 63 SRP was suggested to be a serine protease based on the fact that its activity was inhibited by the protease inhibitor PMSF. The optimal temperature for the activity of the 70 ku protease was 50°C. The maximal activity was observed at pH 6-9, some activity could be observed on the gel slices incubated at pH 5 or 11. The 63 SRP was partly purified by the way of ammonium sulfate precipitation and then gel slicing after gel elec-trophoresis.
基金National Program on Key Basic Research Project by the Ministry of Science and Technology of China(2014CB745100)the National Natural Science Foundation of China(21676190 and 21621004)the Innovative Talents and Platform Program of Tianjin(16PTGCCX00140 and 16PTSYJC00050).
文摘Poly(ethylene terephthalate)hydrolase(PETase)from Ideonella sakaiensis exhibits a strong ability to degrade poly(ethylene terephthalate)(PET)at room temperature,and is thus regarded as a potential tool to solve the issue of polyester plastic pollution.Therefore,we explored the interaction between PETase and the substrate(a dimer of the PET monomer ethylene terephthalate,2PET),using a model of PETase and its substrate.In this study,we focused on six key residues around the substrate-binding groove in order to create novel high-efficiency PETase mutants through protein engineering.These PETase mutants were designed and tested.The enzymatic activities of the R61A,L88F,and I179F mutants,which were obtained with a rapid cell-free screening system,exhibited 1.4 fold,2.1 fold,and 2.5 fold increases,respectively,in comparison with wild-type PETase.The I179F mutant showed the highest activity,with the degradation rate of a PET film reaching 22.5 mg perμmol·L^-1 PETase per day.Thus,this study has created enhanced artificial PETase enzymes through the rational protein engineering of key hydrophobic sites,and has further illustrated the potential of biodegradable plastics.
基金the National Institute of Health，the National Natural Science Foundation of China，National Transgenic Crop Initiative
文摘Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.
基金supported by the National Basic Research Program of China(973 Program)(Nos.2007CB108703 and 2011CB915404)the National Natural Science Foundation of China(No.30921003)
文摘In flowering plants, self-incompatibility （SI） serves as an important intraspecific reproductive barrier to promote outbreeding. In species from the Solanaceae, Plantaginaceae and Rosaceae, S-RNase and SLF （S-locus F-box） proteins have been shown to control the female and male specificity of SI, respectively. However, little is known about structure features of the SLF protein apart from its conserved F-box domain. Here we show that the SLF C-terminal region possesses a novel ubiquitin-binding domain （UBD） structure conserved among the SLF protein family. By using an ex vivo system of Nicotiana benthamiana, we found that the UBD mediates the SLF protein turnover by the ubiquitin-proteasome pathway. Furthermore, we detected that the SLF protein was directly involved in S-RNase degradation. Taken together, our results provide a novel insight into the SLF structure and highlight a potential role of SLF protein stability and degradation in S-RNase-based self-incompatibility.
