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Zhang K, Logacheva MD, Meng Y, Hu J, Wan D, Li L, Janovská D, Wang Z, Georgiev MI, Yu Z, Yang F, Yan M, Zhou M. Jasmonate-responsive MYB factors spatially repress rutin biosynthesis in Fagopyrum tataricum. J Exp Bot 2018; 69:1955-1966. [PMID: 29394372 PMCID: PMC6018783 DOI: 10.1093/jxb/ery032] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/16/2018] [Indexed: 05/17/2023]
Abstract
Jasmonates are plant hormones that induce the accumulation of many secondary metabolites, such as rutin in buckwheat, via regulation of jasmonate-responsive transcription factors. Here, we report on the identification of a clade of jasmonate-responsive subgroup 4 MYB transcription factors, FtMYB13, FtMYB14, FtMYB15, and FtMYB16, which directly repress rutin biosynthesis in Fagopyrum tataricum. Immunoblot analysis showed that FtMYB13, FtMYB14, and FtMYB15 could be degraded via the 26S proteasome in the COI1-dependent jasmonate signaling pathway, and that this degradation is due to the SID motif in their C-terminus. Yeast two-hybrid and bimolecular fluorescence complementation assays revealed that FtMYB13, FtMYB14, and FtMYB15 interact with the importin protein Sensitive to ABA and Drought 2 (FtSAD2) in stem and inflorescence. Furthermore, the key repressor of jasmonate signaling FtJAZ1 specifically interacts with FtMYB13. Point mutation analysis showed that the conserved Asp residue of the SID domain contributes to mediating protein-protein interaction. Protoplast transient activation assays demonstrated that FtMYB13, FtMYB14, and FtMYB15 directly repress phenylalanine ammonia lyase (FtPAL) gene expression, and FtSAD2 and FtJAZ1 significantly promote the repressing activity of FtMYBs. These findings may ultimately be promising for further engineering of plant secondary metabolism.
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Affiliation(s)
- Kaixuan Zhang
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Maria D Logacheva
- Department of Evolutionary Biochemistry, AN Belozersky Institute of Physico-Chemical Biology, MV Lomonosov Moscow State University, Moscow, Russia
| | - Yu Meng
- College of Landscape and Travel, Agricultural University of Hebei, Baoding, China
| | - Jianping Hu
- College of Agricultural Science, Xichang University, Xichang, Sichuan, China
| | - Dongpu Wan
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Agriculture, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Long Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan, China
| | - Dagmar Janovská
- Department of Gene Bank, Crop Research Institute, Drnovská, Czech Republic
| | - Zhiyong Wang
- College of Agriculture, Hainan University, Haikou, Hainan, China
| | - Milen I Georgiev
- Group of Plant Cell Biotechnology and Metabolomics, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Plovdiv, Bulgaria
- Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria
| | - Zhuo Yu
- College of Agriculture, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Fuyu Yang
- Grassland Institute, China Agricultural University, Beijing, China
| | - Mingli Yan
- School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan, China
| | - Meiliang Zhou
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
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马 庆, 余 佩, 张 帆, 李 玉, 杨 曙, 莫 贤, 莫 凯, 丁 颖, 陈 斯. [Mechanism of heat shock protein 90 for regulating 26S proteasome in hyperthermia]. Nan Fang Yi Ke Da Xue Xue Bao 2016; 37:537-541. [PMID: 28446410 PMCID: PMC6744107 DOI: 10.3969/j.issn.1673-4254.2017.04.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Indexed: 12/08/2022]
Abstract
OBJECTIVE To investigate the mechanism by which heat shock protein 90 (HSP90) regulates 26S proteasome in hyperthermia. METHODS Hyperthermic HepG2 cell models established by exposure of the cells to 42 degrees celsius; for 3, 6, 12, and 24 h were examined for production of reactive oxygen species (ROS) and cell proliferation, and the changes in Hsp90α and 26S proteasome were analyzed. RESULTS ROS production in the cells increased significantly after hyperthermia (F=28.958, P<0.001), and the cell proliferation was suppressed progressively as the heat exposure time extended (F=621.704, P<0.001). Hyperthermia up-regulated Hsp90α but decreased the expression level (F=164.174, P<0.001) and activity (F=133.043, P<0.001) of 26S proteasome. The cells transfected with a small interfering RNA targeting Hsp90α also showed significantly decreased expression of 26S proteasome (F=180.231, P<0.001). CONCLUSION The intracellular ROS production increases as the hyperthermia time extends. Heat stress and ROS together cause protein denature, leading to increased HSP90 consumption and further to HSP90 deficiency for maintaining 26S proteasome assembly and stability. The accumulation of denatured protein causes unfolded protein reaction in the cells to eventually result in cell death.
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Affiliation(s)
- 庆荣 马
- 广东药科大学附属第一医院胸外科,广东 广州 510080Department of Thoracic Surgery, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 佩芝 余
- 广东药科大学附属第一医院 检验科,广东 广州 510080Clinical Laboratory, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 帆 张
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 玉齐 李
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 曙 杨
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 贤毅 莫
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 凯岚 莫
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 颖 丁
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - 斯泽 陈
- 广东药科大学附属第一医院肿瘤科,广东 广州 510080Department of Oncology, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
- 陈斯泽,博士,副教授,副主任医师,E-mail:
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Abstract
The ubiquitin-proteasome pathway for protein degradation has emerged as one of the most important mechanisms for regulation of a wide spectrum of cellular functions in virtually all eukaryotic organisms. Specifically, in plants, the ubiquitin/26S proteasome system (UPS) regulates protein degradation and contributes significantly to development of a wide range of processes, including immune response, development and programmed cell death. Moreover, increasing evidence suggests that numerous plant pathogens, such as Agrobacterium, exploit the host UPS for efficient infection, emphasizing the importance of UPS in plant-pathogen interactions. The substrate specificity of UPS is achieved by the E3 ubiquitin ligase that acts in concert with the E1 and E2 ligases to recognize and mark specific protein molecules destined for degradation by attaching to them chains of ubiquitin molecules. One class of the E3 ligases is the SCF (Skp1/Cullin/F-box protein) complex, which specifically recognizes the UPS substrates and targets them for ubiquitination via its F-box protein component. To investigate a potential role of UPS in a biological process of interest, it is important to devise a simple and reliable assay for UPS-mediated protein degradation. Here, we describe one such assay using a plant cell-free system. This assay can be adapted for studies of the roles of regulated protein degradation in diverse cellular processes, with a special focus on the F-box protein-substrate interactions.
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Affiliation(s)
- Elena García-Cano
- Department of Biochemistry and Cell Biology, Stony Brook University, State University of New York;
| | - Adi Zaltsman
- Department of Biochemistry and Cell Biology, Stony Brook University, State University of New York
| | - Vitaly Citovsky
- Department of Biochemistry and Cell Biology, Stony Brook University, State University of New York
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Patra B, Pattanaik S, Yuan L. Proteolytic degradation of the flavonoid regulators, TRANSPARENT TESTA8 and TRANSPARENT TESTA GLABRA1, in Arabidopsis is mediated by the ubiquitin/26Sproteasome system. Plant Signal Behav 2013; 8:doi: 10.4161/psb.25901. [PMID: 23921543 PMCID: PMC4091075 DOI: 10.4161/psb.25901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Regulated proteolysis by the ubiquitin/26S proteasome system (UPS) has emerged as a major posttranslational control mechanism regulating transcription factor (TF) activity in plants. Anthocyanin biosynthesis in Arabidopsis is regulated by a ternary complex comprised of basic helix-loop-helix (bHLH), R2R3MYB and WD-repeat (WDR) proteins. The bHLH TF, TRAN SPAR ENT TESTA 8 (TT 8), and the WDR protein, TRAN SPAR ENT TESTA GLABRA 1 (TT G1), are essential for expression of late flavonoid biosynthesis genes. Previous studies have demonstrated that the turnover of several anthocyanin pathway regulators is controlled by the UPS. Here, we show that TT 8 and TT G1 are short-lived and targeted by the UPS for degradation. Our findings further extend our understanding of the role of the UPS in the regulation of anthocyanin biosynthesis in plants.
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Affiliation(s)
- Barunava Patra
- Kentucky Tobacco Research and Development Center; University of Kentucky; Lexington, KY USA
| | - Sitakanta Pattanaik
- Kentucky Tobacco Research and Development Center; University of Kentucky; Lexington, KY USA
- Department of Plant and Soil Sciences; University of Kentucky; Lexington, KY USA
- Correspondence to: Sitakanta Pattanaik, and Ling Yuan,
| | - Ling Yuan
- Kentucky Tobacco Research and Development Center; University of Kentucky; Lexington, KY USA
- Department of Plant and Soil Sciences; University of Kentucky; Lexington, KY USA
- Correspondence to: Sitakanta Pattanaik, and Ling Yuan,
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Lee KH, Marshall RS, Slivicke LM, Vierstra RD. Genetic analyses of the Arabidopsis 26S proteasome regulatory particle reveal its importance during light stress and a specific role for the N-terminus of RPT2 in development. Plant Signal Behav 2012; 7:973-978. [PMID: 22836496 PMCID: PMC3474698 DOI: 10.4161/psb.20934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The 26S proteasome subunit RPT2 is a component of the hexameric ring of AAA-ATPases that forms the base of the 19S regulatory particle (RP). This subunit has specific roles in the yeast and mammalian proteasomes by helping promote assembly of the RP with the 20S core protease (CP) and gate the CP to prevent indiscriminate degradation of cytosolic and nuclear proteins. In plants, this subunit plays an important role in diverse processes that include shoot and root apical meristem maintenance, cell size regulation, trichome branching, and stress responses. Recently, we reported that mutants in RPT2 and several other RP subunits have reduced histone levels, suggesting that at least some of the pleiotropic phenotypes observed in these plants result from aberrant nucleosome assembly. Here, we expand our genetic analysis of RPT2 in Arabidopsis to shed additional light on the roles of the N- and C-terminal ends. We also present data showing that plants bearing mutations in RP subunit genes have their seedling phenotypes exacerbated by prolonged light exposure.
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6
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Abstract
Ubiquitylation marks proteins for destruction by the 26S proteasome. These signals are deciphered and targeted by distinct direct and indirect pathways involving a set of evolutionarily conserved ubiquitin receptors. Although biochemical and structural studies have revealed the mechanistic complexity of these substrate recognition pathways, conclusive evidence of the in vivo relevance of their substrate recognition function is currently not available. We recently showed that the structural elements involved in substrate recognition are not responsible for the important roles of the ubiquitin receptor RPN10 in vegetative and reproductive growth or for the abundance of the two-capped proteasomes (RP2-CP). Moreover, Arabidopsis plants subjected to severe knockdown or knockout any of the major ubiquitin receptors displayed wild-type phenotypes. Our results clearly suggest a functional redundancy of the major Arabidopsis ubiquitin receptors, and this evolved multiplicity is probably used to secure the substrates delivery. Based on the reduced abundance of RP2-CP in rpn10-2 and a role of RPN10 in lid-base association, a structural role of RPN10 in 26S proteasome stability is likely to be more relevant in vivo. Further efforts using structural and functional analyses in higher-order mutants to identify the specific biological functions of substrate recognition for the major Arabidopsis ubiquitin receptors are described here.
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Affiliation(s)
- Ya-Ling Lin
- Institute of Plant and Microbial Biology; Academia Sinica; Taipei, Taiwan
- Graduate Institute of Biotechnology; National Chung-Hsing University; Taichung, Taiwan
- Molecular and Biological Agricultural Sciences Program; Taiwan International Graduate Program; National Chung-Hsing University and Academia Sinica; Taipei, Taiwan
| | - Hongyong Fu
- Institute of Plant and Microbial Biology; Academia Sinica; Taipei, Taiwan
- Department of Life Sciences; National Chung-Hsing University; Taichung, Taiwan
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Kim S, Nishide A, Saeki Y, Takagi K, Tanaka K, Kato K, Mizushima T. New crystal structure of the proteasome-dedicated chaperone Rpn14 at 1.6 Å resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:517-21. [PMID: 22691779 PMCID: PMC3374504 DOI: 10.1107/s1744309112011359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 03/15/2012] [Indexed: 11/10/2022]
Abstract
The 26S proteasome is an ATP-dependent protease responsible for selective degradation of polyubiquitylated proteins. Recent studies have suggested that proteasome assembly is a highly ordered multi-step process assisted by specific chaperones. Rpn14, an assembly chaperone for ATPase-ring formation, specifically recognizes the ATPase subunit Rpt6. The structure of Rpn14 at 2.0 Å resolution in space group P6(4) has previously been reported, but the detailed mechanism of Rpn14 function remains unclear. Here, a new crystal structure of Rpn14 with an E384A mutation is presented in space group P2(1) at 1.6 Å resolution. This high-resolution structure provides a framework for understanding proteasome assembly.
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Affiliation(s)
- Sangwoo Kim
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Akira Nishide
- Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yasushi Saeki
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Kenji Takagi
- Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Tsunehiro Mizushima
- Picobiology Institute, Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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8
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Lee JH, Kim WT. Regulation of abiotic stress signal transduction by E3 ubiquitin ligases in Arabidopsis. Mol Cells 2011; 31:201-8. [PMID: 21347703 PMCID: PMC3932693 DOI: 10.1007/s10059-011-0031-9] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 12/23/2010] [Accepted: 12/24/2010] [Indexed: 12/25/2022] Open
Abstract
Ubiquitination is a unique protein degradation system utilized by eukaryotes to efficiently degrade detrimental cellular proteins and control the entire pool of regulatory components. In plants, adaptation in response to various abiotic stresses can be achieved through ubiquitination and the resulting degradation of components specific to these stress signalings. Arabidopsis has more than 1,400 E3 enzymes, indicating E3 ligase acts as a main determinant of substrate specificity. However, as only a minority of E3 ligases related to abiotic stress signaling have been studied in Arabidopsis, the further elucidation of the biological roles and related substrates of newly identified E3 ligases is essential in order to clarify the functional relationship between abiotic stress and E3 ligases. Here, we review the current knowledge and future prospects of the regulatory mechanism and role of several E3 ligases involved in abiotic stress signal transduction in Arabidopsis. As another potential approach to understand how ubiquitination is involved in such signaling, we also briefly introduce factors that regulate the activity of cullin in multisubunit E3 ligase complexes.
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Affiliation(s)
- Jae-Hoon Lee
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA
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Zhang Z, Wang H, Luo D, Zeng M, Huang H, Cui X. Convergence of the 26S proteasome and the REVOLUTA pathways in regulating inflorescence and floral meristem functions in Arabidopsis. J Exp Bot 2011; 62:359-69. [PMID: 20797995 PMCID: PMC2993919 DOI: 10.1093/jxb/erq277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The 26S proteasome is a large multisubunit proteolytic complex, regulating growth and development in eukaryotes by selective removal of short-lived regulatory proteins. Here, it is shown that the 26S proteasome and the transcription factor gene REVOLUTA (REV) act together in maintaining inflorescence and floral meristem (IM and FM) functions. The characterization of a newly identified Arabidopsis mutant, designated ae4 (asymmetric leaves1/2 enhancer4), which carries a mutation in the gene encoding the 26S proteasome subunit, RPN2a, is reported. ae4 and rev have minor defects in phyllotaxy structure and meristem initiation, respectively, whereas ae4 rev demonstrated strong developmental defects. Compared with the rev single mutant, an increased percentage of ae4 rev plants exhibited abnormal vegetative shoot apical and axillary meristems. After flowering, ae4 rev first gave rise to a few normal-looking flowers, and then flowers with reduced numbers of all types of floral organs. In late reproductive development, instead of flowers, the ae4 rev IM produced numerous filamentous structures, which contained cells seen only in the floral organs, and then carpelloid organs. In situ hybridization revealed that expression of the WUSCHEL and CLAVATA3 genes was severely down-regulated or absent in the late appearing ae4 rev primordia, but the genes were strongly expressed in top-layer cells of inflorescence tips. Double mutant plants combining rev with other 26S proteasome subunit mutants, rpn1a and rpn9a, resembled ae4 rev, suggesting that the 26S proteasome might act as a whole in regulating IM and FM functions.
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Affiliation(s)
| | | | | | | | | | - Xiaofeng Cui
- To whom correspondence should be addressed. E-mail:
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10
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Abstract
The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins to control many cellular events. The Arabidopsis genome contains two genes, AtRPT2a and AtRPT2b, which encode paralog molecules of the RPT2 subunit of 19S proteasome. We demonstrated that mutation of the AtRPT2a gene causes a specific phenotype of enlarged leaves due to increased cell size in correlation with expanded endoreduplication. This phenotype was also observed in the knockout mutant of AtRPT5a, which encodes one of the paralogs of the RPT5 subunit. Taken together, this suggests that a cell size-specific proteasome consisting of AtRPT2a and AtRPT5a is involved in controlling cell size during leaf development.
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Affiliation(s)
- Kaori Sako
- Graduate School of Life Science and Division of Science, Hokkaido University, Sapporo, Japan
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Bardag-Gorce F, Oliva J, Li J, French BA, French SW. SAMe prevents the induction of the immunoproteasome and preserves the 26S proteasome in the DDC-induced MDB mouse model. Exp Mol Pathol 2010; 88:353-62. [PMID: 20223233 PMCID: PMC3315394 DOI: 10.1016/j.yexmp.2010.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
Abstract
Mallory-Denk bodies (MDBs) form in the liver of alcoholic patients. This occurs because of the accumulation and aggregation of ubiquitinated cytokeratins, which hypothetically is due to the ubiquitin-proteasome pathway's (UPP) failure to degrade the cytokeratins. The experimental model of MDB formation was used in which MDBs were induced by refeeding DDC to drug-primed mice. The gene expression and protein levels of LMP2, LMP7 and MECL-1, the catalytic subunits in the immunoproteasome, as well as FAT10, were increased in the liver cells forming MDBs but not in the intervening normal hepatocytes. Chymotrypsin-like activity of the UPP was decreased by DDC refeeding, indicating that a switch from the UPP to the immunoproteasome had occurred at the expense of the 26S proteasome. The failure of the UPP to digest cytokeratins would explain MDB aggregate formation. SAMe prevented the decrease in UPP activity, the increase in LMP2, LMP7, and MECL-1 protein levels and MDB formation induced by DDC. DDC refeeding also induced the TNFalpha and IFNgamma receptors. SAMe prevented the increase in the TNFalpha and IFNgamma receptors, supporting the idea that TNFalpha and IFNgamma were responsible for the up regulation of LMP2, LPM7, and FAT10. These results support the conclusion that MDBs form in FAT10 over-expressing hepatocytes where the up regulation of the immunoproteasome occurs at the expense of the 26S proteasome.
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Affiliation(s)
- Fawzia Bardag-Gorce
- Department of Pathology, LABioMed at Harbor-UCLA Medical Center, Torrance, CA 90509, USA.
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Bardag-Gorce F, Oliva J, Lin A, Li J, French BA, French SW. SAMe prevents the up regulation of toll-like receptor signaling in Mallory-Denk body forming hepatocytes. Exp Mol Pathol 2010; 88:376-9. [PMID: 20206621 PMCID: PMC2901103 DOI: 10.1016/j.yexmp.2010.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 02/18/2010] [Indexed: 01/22/2023]
Abstract
Mallory-Denk body (MDB) formation is a component of alcoholic and non alcoholic hepatitis. In the present study, the role of the toll-like receptor (TLR) signaling pathway was investigated in the mechanism of MDB formation in the DDC-fed mouse model. Microarray analysis data mining, performed on the livers of drug-primed mice refed DDC, showed that TLR2/4 gene expression was significantly up regulated by DDC refeeding. SAMe supplementation prevented this up regulation and prevented the formation of MDBs. qRT-PCR analysis confirmed these results. TLR2/4 activates the adapter protein MyD88. The levels of MyD88 were increased by DDC refeeding. The increase of MyD88 was also prevented by SAMe supplementation. Results showed that MyD88-independent TLR3/4-TRIF-IRF3 pathway was not up regulated in the liver of DDC refed mice. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is the downstream protein recruited by the MyD88/IRAK protein complex, and is involved in the regulation of innate immune responses. Results showed a significant increase in the levels of TRAF-6. TRAF-6 activation leads to activation of NFkB and the mitogen-activated protein kinase (MAPK) cascade. The TRAF-6 increase was ameliorated by SAMe supplementation. These results suggest that DDC induces MDB formation through the TLR2/4 and MyD88-dependent signaling pathway. In conclusion, SAMe blocked the over-expression of TLR2/4, and their downstream signaling components MyD88 and TRAF-6. SAMe prevented the DDC-induced up regulation of the TLR signaling pathways, probably by preventing the up regulation of INF-gamma receptors by DDC feeding. INFgamma stimulates the up regulation of TLR2. The ability of SAMe feeding to prevent TLR signaling up regulation has not been previously described.
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Visekruna A, Slavova N, Dullat S, Gröne J, Kroesen AJ, Ritz JP, Buhr HJ, Steinhoff U. Expression of catalytic proteasome subunits in the gut of patients with Crohn's disease. Int J Colorectal Dis 2009; 24:1133-9. [PMID: 19274467 PMCID: PMC2733182 DOI: 10.1007/s00384-009-0679-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/19/2009] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND PURPOSE Activation of the transcription factor NF-kappaB by proteasomes and subsequent nuclear translocation of cytoplasmatic complexes play a crucial role in the intestinal inflammation. Proteasomes have a pivotal function in NF-kappaB activation by mediating degradation of inhibitory IkappaB proteins and processing of NF-kappaB precursor proteins. This study aims to analyze the expression of the human proteasome subunits in colonic tissue of patients with Crohn's disease. MATERIALS AND METHODS Thirteen patients with Crohn's disease and 12 control patients were studied. The expression of immunoproteasomes and constitutive proteasomes was examined by Western blot analysis, immunoflourescence and quantitative real-time PCR. For real-time PCR, AK2C was used as housekeeping gene. RESULTS The results indicate the influence of the intestinal inflammation on the expression of the proteasomes in Crohn's disease. Proteasomes from inflamed intestine of patients with Crohn's disease showed significantly increased expression of immunosubunits on both protein and mRNA levels. Especially, the replacement of the constitutive proteasome subunit beta1 by inducible immunosubunit beta1i was observed in patients with active Crohn's disease. In contrast, relatively low abundance of immunoproteasomes was found in control tissue. CONCLUSIONS Our data demonstrate that in contrast to normal colonic tissue, the expression of immunoproteasomes was evidently increased in the inflamed colonic mucosa of patients with Crohn's disease. Thus, the chronic intestinal inflammation process in Crohn's disease leads to significant alterations of proteasome subsets.
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Affiliation(s)
- Alexander Visekruna
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Nadia Slavova
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Sonja Dullat
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Jörn Gröne
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Anton-Josef Kroesen
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Jörg-Peter Ritz
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Heinz-Johannes Buhr
- Department of Surgery I, Charité-Medical School, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
| | - Ulrich Steinhoff
- Max-Planck Institute of Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
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14
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Plosky BS, Vidal AE, de Henestrosa ARF, McLenigan MP, McDonald JP, Mead S, Woodgate R. Controlling the subcellular localization of DNA polymerases iota and eta via interactions with ubiquitin. EMBO J 2006; 25:2847-55. [PMID: 16763556 PMCID: PMC1500862 DOI: 10.1038/sj.emboj.7601178] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 05/12/2006] [Indexed: 01/18/2023] Open
Abstract
Y-family DNA polymerases have spacious active sites that can accommodate a wide variety of geometric distortions. As a consequence, they are considerably more error-prone than high-fidelity replicases. It is hardly surprising, therefore, that the in vivo activity of these polymerases is tightly regulated, so as to minimize their inadvertent access to primer-termini. We report here that one such mechanism employed by human cells relies on a specific and direct interaction between DNA polymerases iota and eta with ubiquitin (Ub). Indeed, we show that both polymerases interact noncovalently with free polyUb chains, as well as mono-ubiquitinated proliferating cell nuclear antigen (Ub-PCNA). Mutants of poliota (P692R) and poleta (H654A) were isolated that are defective in their interactions with polyUb and Ub-PCNA, whilst retaining their ability to interact with unmodified PCNA. Interestingly, the polymerase mutants exhibit significantly lower levels of replication foci in response to DNA damage, thereby highlighting the biological importance of the polymerase-Ub interaction in regulating the access of the TLS polymerases to stalled replication forks in vivo.
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Affiliation(s)
- Brian S Plosky
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Antonio E Vidal
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Antonio R Fernández de Henestrosa
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Mary P McLenigan
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - John P McDonald
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Samantha Mead
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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15
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Bewley MC, Graziano V, Griffin K, Flanagan JM. The asymmetry in the mature amino-terminus of ClpP facilitates a local symmetry match in ClpAP and ClpXP complexes. J Struct Biol 2006; 153:113-28. [PMID: 16406682 PMCID: PMC4377234 DOI: 10.1016/j.jsb.2005.09.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 09/09/2005] [Accepted: 09/13/2005] [Indexed: 01/07/2023]
Abstract
ClpP is a self-compartmentalized proteolytic assembly comprised of two, stacked, heptameric rings that, when associated with its cognate hexameric ATPase (ClpA or ClpX), form the ClpAP and ClpXP ATP-dependent protease, respectively. The symmetry mismatch is an absolute feature of this large energy-dependent protease and also of the proteasome, which shares a similar barrel-shaped architecture, but how it is accommodated within the complex has yet to be understood, despite recent structural investigations, due in part to the conformational lability of the N-termini. We present the structures of Escherichia coli ClpP to 1.9A and an inactive variant that provide some clues for how this might be achieved. In the wild type protein, the highly conserved N-terminal 20 residues can be grouped into two major structural classes. In the first, a loop formed by residues 10-15 protrudes out of the central access channel extending approximately 12-15A from the surface of the oligomer resulting in the closing of the access channel observed in one ring. Similar loops are implied to be exclusively observed in human ClpP and a variant of ClpP from Streptococcus pneumoniae. In the other ring, a second class of loop is visible in the structure of wt ClpP from E. coli that forms closer to residue 16 and faces toward the interior of the molecule creating an open conformation of the access channel. In both classes, residues 18-20 provide a conserved interaction surface. In the inactive variant, a third class of N-terminal conformation is observed, which arises from a conformational change in the position of F17. We have performed a detailed functional analysis on each of the first 20 amino acid residues of ClpP. Residues that extend beyond the plane of the molecule (10-15) have a lesser effect on ATPase interaction than those lining the pore (1-7 and 16-20). Based upon our structure-function analysis, we present a model to explain the widely disparate effects of individual residues on ClpP-ATPase complex formation and also a possible functional reason for this mismatch.
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Affiliation(s)
- Maria C. Bewley
- Department of Biochemistry and Molecular Biology, The Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, P.O. Box 850, Hershey, PA 17033, USA
| | - Vito Graziano
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Kathleen Griffin
- Department of Biochemistry and Molecular Biology, The Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, P.O. Box 850, Hershey, PA 17033, USA
| | - John M. Flanagan
- Department of Biochemistry and Molecular Biology, The Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, P.O. Box 850, Hershey, PA 17033, USA
- Corresponding author. (J.M. Flanagan)
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