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Matthaei A, Joecks S, Frauenstein A, Bruening J, Bankwitz D, Friesland M, Gerold G, Vieyres G, Kaderali L, Meissner F, Pietschmann T. Landscape of protein-protein interactions during hepatitis C virus assembly and release. Microbiol Spectr 2024; 12:e0256222. [PMID: 38230952 PMCID: PMC10846047 DOI: 10.1128/spectrum.02562-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/11/2023] [Indexed: 01/18/2024] Open
Abstract
Assembly of infectious hepatitis C virus (HCV) particles requires multiple cellular proteins including for instance apolipoprotein E (ApoE). To describe these protein-protein interactions, we performed an affinity purification mass spectrometry screen of HCV-infected cells. We used functional viral constructs with epitope-tagged envelope protein 2 (E2), protein (p) 7, or nonstructural protein 4B (NS4B) as well as cells expressing a tagged variant of ApoE. We also evaluated assembly stage-dependent remodeling of protein complexes by using viral mutants carrying point mutations abrogating particle production at distinct steps of the HCV particle production cascade. Five ApoE binding proteins, 12 p7 binders, 7 primary E2 interactors, and 24 proteins interacting with NS4B were detected. Cell-derived PREB, STT3B, and SPCS2 as well as viral NS2 interacted with both p7 and E2. Only GTF3C3 interacted with E2 and NS4B, highlighting that HCV assembly and replication complexes exhibit largely distinct interactomes. An HCV core protein mutation, preventing core protein decoration of lipid droplets, profoundly altered the E2 interactome. In cells replicating this mutant, E2 interactions with HSPA5, STT3A/B, RAD23A/B, and ZNF860 were significantly enhanced, suggesting that E2 protein interactions partly depend on core protein functions. Bioinformatic and functional studies including STRING network analyses, RNA interference, and ectopic expression support a role of Rad23A and Rad23B in facilitating HCV infectious virus production. Both Rad23A and Rad23B are involved in the endoplasmic reticulum (ER)-associated protein degradation (ERAD). Collectively, our results provide a map of host proteins interacting with HCV assembly proteins, and they give evidence for the involvement of ER protein folding machineries and the ERAD pathway in the late stages of the HCV replication cycle.IMPORTANCEHepatitis C virus (HCV) establishes chronic infections in the majority of exposed individuals. This capacity likely depends on viral immune evasion strategies. One feature likely contributing to persistence is the formation of so-called lipo-viro particles. These peculiar virions consist of viral structural proteins and cellular lipids and lipoproteins, the latter of which aid in viral attachment and cell entry and likely antibody escape. To learn about how lipo-viro particles are coined, here, we provide a comprehensive overview of protein-protein interactions in virus-producing cells. We identify numerous novel and specific HCV E2, p7, and cellular apolipoprotein E-interacting proteins. Pathway analyses of these interactors show that proteins participating in processes such as endoplasmic reticulum (ER) protein folding, ER-associated protein degradation, and glycosylation are heavily engaged in virus production. Moreover, we find that the proteome of HCV replication sites is distinct from the assembly proteome, suggesting that transport process likely shuttles viral RNA to assembly sites.
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Affiliation(s)
- Alina Matthaei
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
| | - Sebastian Joecks
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
| | - Annika Frauenstein
- RG Experimental Systems Immunology, Max-Planck Institute for Biochemistry, Planegg, Bavaria, Germany
| | - Janina Bruening
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
| | - Dorothea Bankwitz
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
| | - Martina Friesland
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
| | - Gisa Gerold
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
- Department of Biochemistry & Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Lower Saxony, Germany
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine (WCMM), Umeå University, Umeå, Sweden
| | - Gabrielle Vieyres
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
- Junior Research Group “Cell Biology of RNA Viruses,” Leibniz Institute of Experimental Virology, Hamburg, Germany
| | - Lars Kaderali
- Institute of Bioinformatics, University Medicine Greifswald, Greifswald, Germany
| | - Felix Meissner
- RG Experimental Systems Immunology, Max-Planck Institute for Biochemistry, Planegg, Bavaria, Germany
- Systems Immunology and Proteomics, Institute of Innate Immunity, Medical Faculty, University of Bonn, Bonn, Germany
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany
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De Masi R, Orlando S. GANAB and N-Glycans Substrates Are Relevant in Human Physiology, Polycystic Pathology and Multiple Sclerosis: A Review. Int J Mol Sci 2022; 23:7373. [PMID: 35806376 PMCID: PMC9266668 DOI: 10.3390/ijms23137373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
Glycans are one of the four fundamental macromolecular components of living matter, and they are highly regulated in the cell. Their functions are metabolic, structural and modulatory. In particular, ER resident N-glycans participate with the Glc3Man9GlcNAc2 highly conserved sequence, in protein folding process, where the physiological balance between glycosylation/deglycosylation on the innermost glucose residue takes place, according GANAB/UGGT concentration ratio. However, under abnormal conditions, the cell adapts to the glucose availability by adopting an aerobic or anaerobic regimen of glycolysis, or to external stimuli through internal or external recognition patterns, so it responds to pathogenic noxa with unfolded protein response (UPR). UPR can affect Multiple Sclerosis (MS) and several neurological and metabolic diseases via the BiP stress sensor, resulting in ATF6, PERK and IRE1 activation. Furthermore, the abnormal GANAB expression has been observed in MS, systemic lupus erythematous, male germinal epithelium and predisposed highly replicating cells of the kidney tubules and bile ducts. The latter is the case of Polycystic Liver Disease (PCLD) and Polycystic Kidney Disease (PCKD), where genetically induced GANAB loss affects polycystin-1 (PC1) and polycystin-2 (PC2), resulting in altered protein quality control and cyst formation phenomenon. Our topics resume the role of glycans in cell physiology, highlighting the N-glycans one, as a substrate of GANAB, which is an emerging key molecule in MS and other human pathologies.
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Affiliation(s)
- Roberto De Masi
- Complex Operative Unit of Neurology, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy;
- Laboratory of Neuroproteomics, Multiple Sclerosis Centre, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy
| | - Stefania Orlando
- Laboratory of Neuroproteomics, Multiple Sclerosis Centre, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy
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Ghenea S, Chiritoiu M, Tacutu R, Miranda-Vizuete A, Petrescu SM. Targeting EDEM protects against ER stress and improves development and survival in C. elegans. PLoS Genet 2022; 18:e1010069. [PMID: 35192599 PMCID: PMC8912907 DOI: 10.1371/journal.pgen.1010069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 03/10/2022] [Accepted: 02/02/2022] [Indexed: 02/07/2023] Open
Abstract
EDEM-1, EDEM-2 and EDEM-3 are key players for the quality control of newly synthesized proteins in the endoplasmic reticulum (ER) by accelerating disposal and degradation of misfolded proteins through ER Associated Degradation (ERAD). Although many previous studies reported the role of individual ERAD components especially in cell-based systems, still little is known about the consequences of ERAD dysfunction under physiological and ER stress conditions in the context of a multicellular organism. Here we report the first individual and combined characterization and functional interplay of EDEM proteins in Caenorhabditis elegans using single, double, and triple mutant combinations. We found that EDEM-2 has a major role in the clearance of misfolded proteins from ER under physiological conditions, whereas EDEM-1 and EDEM-3 roles become prominent under acute ER stress. In contrast to SEL-1 loss, the loss of EDEMs in an intact organism induces only a modest ER stress under physiological conditions. In addition, chronic impairment of EDEM functioning attenuated both XBP-1 activation and up-regulation of the stress chaperone GRP78/BiP, in response to acute ER stress. We also show that pre-conditioning to EDEM loss in acute ER stress restores ER homeostasis and promotes survival by activating ER hormesis. We propose a novel role for EDEM in fine-tuning the ER stress responsiveness that affects ER homeostasis and survival. ER stress and UPRER malfunctions have been implicated in the pathogenesis of neurodegeneration, metabolic and inflammatory diseases as well as tumor progression and diabetes, whereby disturbed ER homeostasis negatively influences the pathology of the disease. Under ER stress conditions, the cells either activate UPRER-dependent cytoprotective mechanisms when ER stress is at subtoxic levels or, in case of an excessive ER stress, the cytotoxic response stimulates cell death. Here, we used Caenorhabditis elegans to study the cellular responses to ER stress at organismal level. We show that EDEMs respond differently to ER stress stimuli, and moreover, EDEMs deficiencies activate an XBP-1 independent adaptive program to promote organism survival under acute ER stress. Corroborated with the fact that loss of EDEM-2 and EDEM-3 induces resistance to acute ER stress in an intact organism, our data implicate EDEM proteins in a broader response to ER stress than previously established, which opens a new avenue for understanding the regulation of ER stress with implications for clinical and therapeutic investigations.
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Affiliation(s)
- Simona Ghenea
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
- * E-mail: (SG); (SMP)
| | - Marioara Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Robi Tacutu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry, Romanian Academy, Bucharest, Romania
| | - Antonio Miranda-Vizuete
- Redox Homeostasis Group, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Stefana Maria Petrescu
- Department of Molecular Cell Biology, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
- * E-mail: (SG); (SMP)
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Katsube M, Ebara N, Maeda M, Kimura Y. Cytosolic Free N-Glycans Are Retro-Transported Into the Endoplasmic Reticulum in Plant Cells. FRONTIERS IN PLANT SCIENCE 2021; 11:610124. [PMID: 33537045 PMCID: PMC7847903 DOI: 10.3389/fpls.2020.610124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
During endoplasmic reticulum (ER)-associated degradation, free N-glycans (FNGs) are produced from misfolded nascent glycoproteins via the combination of the cytosolic peptide N-glycanase (cPNGase) and endo-β-N-acetylglucosaminidase (ENGase) in the plant cytosol. The resulting high-mannose type (HMT)-FNGs, which carry one GlcNAc residue at the reducing end (GN1-FNGs), are ubiquitously found in developing plant cells. In a previous study, we found that HMT-FNGs assisted in protein folding and inhibited β-amyloid fibril formation, suggesting a possible biofunction of FNGs involved in the protein folding system. However, whether these HMT-FNGs occur in the ER, an organelle involved in protein folding, remained unclear. On the contrary, we also reported the presence of plant complex type (PCT)-GN1-FNGs, which carry the Lewisa epitope at the non-reducing end, indicating that these FNGs had been fully processed in the Golgi apparatus. Since plant ENGase was active toward HMT-N-glycans but not PCT-N-glycans that carry β1-2xylosyl and/or α1-3 fucosyl residue(s), these PCT-GN1-FNGs did not appear to be produced from fully processed glycoproteins that harbored PCT-N-glycans via ENGase activity. Interestingly, PCT-GN1-FNGs were found in the extracellular space, suggesting that HMT-GN1-FNGs formed in the cytosol might be transported back to the ER and processed in the Golgi apparatus through the protein secretion pathway. As the first step in elucidating the production mechanism of PCT-GN1-FNGs, we analyzed the structures of free oligosaccharides in plant microsomes and proved that HMT-FNGs (Man9-7GlcNAc1 and Man9-8GlcNAc2) could be found in microsomes, which almost consist of the ER compartments.
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Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
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6
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Du H, Zheng C, Aslam M, Xie X, Wang W, Yang Y, Liu X. Endoplasmic Reticulum-Mediated Protein Quality Control and Endoplasmic Reticulum-Associated Degradation Pathway Explain the Reduction of N-glycoprotein Level Under the Lead Stress. FRONTIERS IN PLANT SCIENCE 2020; 11:598552. [PMID: 33519851 PMCID: PMC7838096 DOI: 10.3389/fpls.2020.598552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/04/2020] [Indexed: 05/06/2023]
Abstract
Different anthropogenic activities result in the continuous increase of metal lead (Pb) in the environment and adversely affect living organisms. Therefore, it is important to investigate the tolerance mechanism in a model organism. Chlamydomonas reinhardtii is an important green eukaryotic model microalga for studying different kinds of biological questions. In this study, the responses of C. reinhardtii were revealed via a comprehensive approach, including physiological, genomic, transcriptomic, glycomic, and bioinformatic techniques. Physiological results showed that the growth rate and soluble protein content were significantly reduced under the high lead stress. Also, the results obtained from the genomic and transcriptomic analyses presented that the endoplasmic reticulum-mediated protein quality control (ERQC) system and endoplasmic reticulum-associated degradation (ERAD) pathway were activated under the third day of high lead stress. The unique upregulated protein disulfide isomerase genes on the ERQC system were proposed to be important for the protein level and protein quality control. The accumulation of specific N-glycans indicated that specific N-glycosylation of proteins might alter the biological functions of proteins to alleviate the Pb stress in alga and/or lead to the degradation of incomplete/misfolded proteins. At the same time, it was observed that genes involved in each process of ERAD were upregulated, suggesting that the ERAD pathway was activated to assist the degradation of incomplete/misfolded proteins. Therefore, it is reasonable to speculate that the reduction of protein level under the high lead stress was related to the activated ERQC system and QRAD pathway. Our findings will provide a solid and reliable foundation and a proposed ERAD working model for further in-depth study of the ERQC system and ERAD pathway under the Pb stress and even other biotic and abiotic stresses.
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Affiliation(s)
- Hong Du
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Canqi Zheng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Muhmmad Aslam
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
- Faculty of Marine Sciences, Lasbela University of Agriculture, Water & Marine Sciences, Uthal, Pakistan
| | - Xihui Xie
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Wanna Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Yingquan Yang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Xiaojuan Liu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, College of Sciences, Institute of Marine Sciences, Shantou University, Shantou, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
- *Correspondence: Xiaojuan Liu,
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7
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Yu S, Ito S, Wada I, Hosokawa N. ER-resident protein 46 (ERp46) triggers the mannose-trimming activity of ER degradation-enhancing α-mannosidase-like protein 3 (EDEM3). J Biol Chem 2018; 293:10663-10674. [PMID: 29784879 DOI: 10.1074/jbc.ra118.003129] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 05/16/2018] [Indexed: 11/06/2022] Open
Abstract
Protein folding in the cell is regulated by several quality-control mechanisms. Correct folding of glycoproteins in the endoplasmic reticulum (ER) is tightly monitored by the recognition of glycan signals by lectins in the ER-associated degradation (ERAD) pathway. In mammals, mannose trimming from N-glycans is crucial for disposal of misfolded glycoproteins. The mannosidases responsible for this process are ER mannosidase I and ER degradation-enhancing α-mannosidase-like proteins (EDEMs). However, the molecular mechanism of mannose removal by EDEMs remains unclear, partly owing to the difficulty of reconstituting mannosidase activity in vitro Here, our analysis of EDEM3-mediated mannose-trimming activity on a misfolded glycoprotein revealed that ERp46, an ER-resident oxidoreductase, associates stably with EDEM3. This interaction, which depended on the redox activity of ERp46, involved formation of a disulfide bond between the cysteine residues of the ERp46 redox-active sites and the EDEM3 α-mannosidase domain. In a defined in vitro system consisting of recombinant proteins purified from HEK293 cells, the mannose-trimming activity of EDEM3 toward the model misfolded substrate, the glycoprotein T-cell receptor α locus (TCRα), was reconstituted only when ERp46 had established a covalent interaction with EDEM3. On the basis of these findings, we propose that disposal of misfolded glycoproteins through mannose trimming is tightly connected to redox-mediated regulation in the ER.
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Affiliation(s)
- Shangyu Yu
- From the Laboratory of Molecular and Cellular Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507
| | - Shinji Ito
- the Medical Research Support Center, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, and
| | - Ikuo Wada
- the Department of Cell Sciences, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Nobuko Hosokawa
- From the Laboratory of Molecular and Cellular Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507,
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Multiple regulatory mechanisms of the biological function of NRF3 (NFE2L3) control cancer cell proliferation. Sci Rep 2017; 7:12494. [PMID: 28970512 PMCID: PMC5624902 DOI: 10.1038/s41598-017-12675-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/18/2017] [Indexed: 12/14/2022] Open
Abstract
Accumulated evidence suggests a physiological relationship between the transcription factor NRF3 (NFE2L3) and cancers. Under physiological conditions, NRF3 is repressed by its endoplasmic reticulum (ER) sequestration. In response to unidentified signals, NRF3 enters the nucleus and modulates gene expression. However, molecular mechanisms underlying the nuclear translocation of NRF3 and its target gene in cancer cells remain poorly understood. We herein report that multiple regulation of NRF3 activities controls cell proliferation. Our analyses reveal that under physiological conditions, NRF3 is rapidly degraded by the ER-associated degradation (ERAD) ubiquitin ligase HRD1 and valosin-containing protein (VCP) in the cytoplasm. Furthermore, NRF3 is also degraded by β-TRCP, an adaptor for the Skp1-Cul1-F-box protein (SCF) ubiquitin ligase in the nucleus. The nuclear translocation of NRF3 from the ER requires the aspartic protease DNA-damage inducible 1 homolog 2 (DDI2) but does not require inhibition of its HRD1-VCP-mediated degradation. Finally, NRF3 mediates gene expression of the cell cycle regulator U2AF homology motif kinase 1 (UHMK1) for cell proliferation. Collectively, our study provides us many insights into the molecular regulation and biological function of NRF3 in cancer cells.
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Chen Q, Liu R, Wang Q, Xie Q. ERAD Tuning of the HRD1 Complex Component AtOS9 Is Modulated by an ER-Bound E2, UBC32. MOLECULAR PLANT 2017; 10:891-894. [PMID: 28040559 DOI: 10.1016/j.molp.2016.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Qian Chen
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ruijun Liu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qian Wang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, P. R. China; The Faculty of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
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Ward BK, Rea SL, Magno AL, Pedersen B, Brown SJ, Mullin S, Arulpragasam A, Ingley E, Conigrave AD, Ratajczak T. The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor. J Cell Physiol 2017; 233:38-56. [PMID: 28419469 DOI: 10.1002/jcp.25957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 04/13/2017] [Indexed: 11/07/2022]
Abstract
The mechanisms responsible for the processing and quality control of the calcium-sensing receptor (CaSR) in the endoplasmic reticulum (ER) are largely unknown. In a yeast two-hybrid screen of the CaSR C-terminal tail (residues 865-1078), we identified osteosarcoma-9 (OS-9) protein as a binding partner. OS-9 is an ER-resident lectin that targets misfolded glycoproteins to the ER-associated degradation (ERAD) pathway through recognition of specific N-glycans by its mannose-6-phosphate receptor homology (MRH) domain. We show by confocal microscopy that the CaSR and OS-9 co-localize in the ER in COS-1 cells. In immunoprecipitation studies with co-expressed OS-9 and CaSR, OS-9 specifically bound the immature form of wild-type CaSR in the ER. OS-9 also bound the immature forms of a CaSR C-terminal deletion mutant and a C677A mutant that remains trapped in the ER, although binding to neither mutant was favored over wild-type receptor. OS-9 binding to immature CaSR required the MRH domain of OS-9 indicating that OS-9 acts as a lectin most likely to target misfolded CaSR to ERAD. Our results also identify two distinct binding interactions between OS-9 and the CaSR, one involving both C-terminal domains of the two proteins and the other involving both N-terminal domains. This suggests the possibility of more than one functional interaction between OS-9 and the CaSR. When we investigated the functional consequences of altered OS-9 expression, neither knockdown nor overexpression of OS-9 was found to have a significant effect on CaSR cell surface expression or CaSR-mediated ERK1/2 phosphorylation.
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Affiliation(s)
- Bryan K Ward
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Sarah L Rea
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Aaron L Magno
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Bernadette Pedersen
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Suzanne J Brown
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Shelby Mullin
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Ajanthy Arulpragasam
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Evan Ingley
- Cell Signalling Group, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Arthur D Conigrave
- School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, New South Wales, Australia
| | - Thomas Ratajczak
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and the Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
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Quality control of glycoprotein folding and ERAD: the role of N-glycan handling, EDEM1 and OS-9. Histochem Cell Biol 2016; 147:269-284. [DOI: 10.1007/s00418-016-1513-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2016] [Indexed: 02/03/2023]
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12
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Varki A. Biological roles of glycans. Glycobiology 2016; 27:3-49. [PMID: 27558841 PMCID: PMC5884436 DOI: 10.1093/glycob/cww086] [Citation(s) in RCA: 1458] [Impact Index Per Article: 182.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 08/15/2016] [Accepted: 08/16/2016] [Indexed: 02/07/2023] Open
Abstract
Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.
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Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093-0687, USA
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Seaayfan E, Defontaine N, Demaretz S, Zaarour N, Laghmani K. OS9 Protein Interacts with Na-K-2Cl Co-transporter (NKCC2) and Targets Its Immature Form for the Endoplasmic Reticulum-associated Degradation Pathway. J Biol Chem 2016. [PMID: 26721884 DOI: 10.1074/jbc.m115.702514.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutations in the renal specific Na-K-2Cl co-transporter (NKCC2) lead to type I Bartter syndrome, a life-threatening kidney disease featuring arterial hypotension along with electrolyte abnormalities. We have previously shown that NKCC2 and its disease-causing mutants are subject to regulation by endoplasmic reticulum-associated degradation (ERAD). The aim of the present study was to identify the protein partners specifically involved in ERAD of NKCC2. To this end, we screened a kidney cDNA library through a yeast two-hybrid assay using NKCC2 C terminus as bait. We identified OS9 (amplified in osteosarcomas) as a novel and specific binding partner of NKCC2. Co-immunoprecipitation assays in renal cells revealed that OS9 association involves mainly the immature form of NKCC2. Accordingly, immunocytochemistry analysis showed that NKCC2 and OS9 co-localize at the endoplasmic reticulum. In cells overexpressing OS9, total cellular NKCC2 protein levels were markedly decreased, an effect blocked by the proteasome inhibitor MG132. Pulse-chase and cycloheximide-chase assays demonstrated that the marked reduction in the co-transporter protein levels was essentially due to increased protein degradation of the immature form of NKCC2. Conversely, knockdown of OS9 by small interfering RNA increased NKCC2 expression by increasing the co-transporter stability. Inactivation of the mannose 6-phosphate receptor homology domain of OS9 had no effect on its action on NKCC2. In contrast, mutations of NKCC2 N-glycosylation sites abolished the effects of OS9, indicating that OS9-induced protein degradation is N-glycan-dependent. In summary, our results demonstrate the presence of an OS9-mediated ERAD pathway in renal cells that degrades immature NKCC2 proteins. The identification and selective modulation of ERAD components specific to NKCC2 and its disease-causing mutants might provide novel therapeutic strategies for the treatment of type I Bartter syndrome.
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Affiliation(s)
- Elie Seaayfan
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Nadia Defontaine
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Sylvie Demaretz
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Nancy Zaarour
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Kamel Laghmani
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
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14
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Seaayfan E, Defontaine N, Demaretz S, Zaarour N, Laghmani K. OS9 Protein Interacts with Na-K-2Cl Co-transporter (NKCC2) and Targets Its Immature Form for the Endoplasmic Reticulum-associated Degradation Pathway. J Biol Chem 2015; 291:4487-502. [PMID: 26721884 DOI: 10.1074/jbc.m115.702514] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Indexed: 01/25/2023] Open
Abstract
Mutations in the renal specific Na-K-2Cl co-transporter (NKCC2) lead to type I Bartter syndrome, a life-threatening kidney disease featuring arterial hypotension along with electrolyte abnormalities. We have previously shown that NKCC2 and its disease-causing mutants are subject to regulation by endoplasmic reticulum-associated degradation (ERAD). The aim of the present study was to identify the protein partners specifically involved in ERAD of NKCC2. To this end, we screened a kidney cDNA library through a yeast two-hybrid assay using NKCC2 C terminus as bait. We identified OS9 (amplified in osteosarcomas) as a novel and specific binding partner of NKCC2. Co-immunoprecipitation assays in renal cells revealed that OS9 association involves mainly the immature form of NKCC2. Accordingly, immunocytochemistry analysis showed that NKCC2 and OS9 co-localize at the endoplasmic reticulum. In cells overexpressing OS9, total cellular NKCC2 protein levels were markedly decreased, an effect blocked by the proteasome inhibitor MG132. Pulse-chase and cycloheximide-chase assays demonstrated that the marked reduction in the co-transporter protein levels was essentially due to increased protein degradation of the immature form of NKCC2. Conversely, knockdown of OS9 by small interfering RNA increased NKCC2 expression by increasing the co-transporter stability. Inactivation of the mannose 6-phosphate receptor homology domain of OS9 had no effect on its action on NKCC2. In contrast, mutations of NKCC2 N-glycosylation sites abolished the effects of OS9, indicating that OS9-induced protein degradation is N-glycan-dependent. In summary, our results demonstrate the presence of an OS9-mediated ERAD pathway in renal cells that degrades immature NKCC2 proteins. The identification and selective modulation of ERAD components specific to NKCC2 and its disease-causing mutants might provide novel therapeutic strategies for the treatment of type I Bartter syndrome.
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Affiliation(s)
- Elie Seaayfan
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Nadia Defontaine
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Sylvie Demaretz
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Nancy Zaarour
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
| | - Kamel Laghmani
- From INSERM, Centre de Recherche des Cordeliers, U1138, Paris 75006, France, CNRS, ERL8228, Paris 75006, France, Université Pierre et Marie Curie, Paris 75006, France, and Université Paris-Descartes, Paris 75005, France
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15
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Ninagawa S, Okada T, Sumitomo Y, Horimoto S, Sugimoto T, Ishikawa T, Takeda S, Yamamoto T, Suzuki T, Kamiya Y, Kato K, Mori K. Forcible destruction of severely misfolded mammalian glycoproteins by the non-glycoprotein ERAD pathway. J Cell Biol 2015; 211:775-84. [PMID: 26572623 PMCID: PMC4657166 DOI: 10.1083/jcb.201504109] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/07/2015] [Indexed: 11/27/2022] Open
Abstract
Higher eukaryotes, but not yeast, are able to extract severely misfolded glycoproteins from the endoplasmic reticulum–associated degradation (ERAD) pathway for glycoproteins and target them to the ERAD pathway for non-glycoproteins to maintain the homeostasis of the ER. Glycoproteins and non-glycoproteins possessing unfolded/misfolded parts in their luminal regions are cleared from the endoplasmic reticulum (ER) by ER-associated degradation (ERAD)-L with distinct mechanisms. Two-step mannose trimming from Man9GlcNAc2 is crucial in the ERAD-L of glycoproteins. We recently showed that this process is initiated by EDEM2 and completed by EDEM3/EDEM1. Here, we constructed chicken and human cells simultaneously deficient in EDEM1/2/3 and analyzed the fates of four ERAD-L substrates containing three potential N-glycosylation sites. We found that native but unstable or somewhat unfolded glycoproteins, such as ATF6α, ATF6α(C), CD3-δ–ΔTM, and EMC1, were stabilized in EDEM1/2/3 triple knockout cells. In marked contrast, degradation of severely misfolded glycoproteins, such as null Hong Kong (NHK) and deletion or insertion mutants of ATF6α(C), CD3-δ–ΔTM, and EMC1, was delayed only at early chase periods, but they were eventually degraded as in wild-type cells. Thus, higher eukaryotes are able to extract severely misfolded glycoproteins from glycoprotein ERAD and target them to the non-glycoprotein ERAD pathway to maintain the homeostasis of the ER.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan
| | - Tetsuya Okada
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoshiki Sumitomo
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Satoshi Horimoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takehiro Sugimoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tokiro Ishikawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Tadashi Suzuki
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, Wako, Saitama 351-0198, Japan
| | - Yukiko Kamiya
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan
| | - Koichi Kato
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan Graduate School of Pharmaceutical Sciences, Nagoya City University, Mizuho-ku, Nagoya, 467-8603, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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16
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D'Alessio C, Dahms NM. Glucosidase II and MRH-domain containing proteins in the secretory pathway. Curr Protein Pept Sci 2015; 16:31-48. [PMID: 25692846 DOI: 10.2174/1389203716666150213160438] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/25/2014] [Accepted: 11/13/2014] [Indexed: 12/24/2022]
Abstract
N-glycosylation in the endoplasmic reticulum (ER) consists of the transfer of a preassembled glycan conserved among species (Glc3Man9GlcNAc2) from a lipid donor to a consensus sequence within a nascent protein that is entering the ER. The protein-linked glycans are then processed by glycosidases and glycosyltransferases in the ER producing specific structures that serve as signalling molecules for the fate of the folding glycoprotein: to stay in the ER during the folding process, to be retrotranslocated to the cytosol for proteasomal degradation if irreversibly misfolded, or to pursue transit through the secretory pathway as a mature glycoprotein. In the ER, each glycan signalling structure is recognized by a specific lectin. A domain similar to that of the mannose 6-phosphate receptors (MPRs) has been identified in several proteins of the secretory pathway. These include the beta subunit of glucosidase II (GII), a key enzyme in the early processing of the transferred glycan that removes middle and innermost glucoses and is involved in quality control of glycoprotein folding in the ER (QC), the lectins OS-9 and XTP3-B, proteins involved in the delivery of ER misfolded proteins to degradation (ERAD), the gamma subunit of the Golgi GlcNAc-1-phosphotransferase, an enzyme involved in generating the mannose 6-phosphate (M6P) signal for sorting acidic hydrolases to lysosomes, and finally the MPRs that deliver those hydrolytic enzymes to the lysosome. Each of the MRH-containing proteins recognizes a different signalling N-glycan structure. Three-dimensional structures of some of the MRH domains have been solved, providing the basis to understand recognition mechanisms.
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Affiliation(s)
| | - Nancy M Dahms
- Laboratory of Glycobiology, Fundación Instituto Leloir - Instituto de Investigaciones Bioquimicas de Buenos Aires-CONICET, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina, and School of Sciences, University of Buenos Aires, C1428EHA, Buenos Aires, Argentina.
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17
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Ferris SP, Kodali VK, Kaufman RJ. Glycoprotein folding and quality-control mechanisms in protein-folding diseases. Dis Model Mech 2015; 7:331-41. [PMID: 24609034 PMCID: PMC3944493 DOI: 10.1242/dmm.014589] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Biosynthesis of proteins – from translation to folding to export – encompasses a complex set of events that are exquisitely regulated and scrutinized to ensure the functional quality of the end products. Cells have evolved to capitalize on multiple post-translational modifications in addition to primary structure to indicate the folding status of nascent polypeptides to the chaperones and other proteins that assist in their folding and export. These modifications can also, in the case of irreversibly misfolded candidates, signal the need for dislocation and degradation. The current Review focuses on the glycoprotein quality-control (GQC) system that utilizes protein N-glycosylation and N-glycan trimming to direct nascent glycopolypeptides through the folding, export and dislocation pathways in the endoplasmic reticulum (ER). A diverse set of pathological conditions rooted in defective as well as over-vigilant ER quality-control systems have been identified, underlining its importance in human health and disease. We describe the GQC pathways and highlight disease and animal models that have been instrumental in clarifying our current understanding of these processes.
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Affiliation(s)
- Sean P Ferris
- Department of Biological Chemistry and Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
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18
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Yuan C, Smith WL. A cyclooxygenase-2-dependent prostaglandin E2 biosynthetic system in the Golgi apparatus. J Biol Chem 2014; 290:5606-20. [PMID: 25548276 DOI: 10.1074/jbc.m114.632463] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cyclooxygenases (COXs) catalyze the committed step in prostaglandin (PG) biosynthesis. COX-1 is constitutively expressed and stable, whereas COX-2 is inducible and short lived. COX-2 is degraded via endoplasmic reticulum (ER)-associated degradation (ERAD) following post-translational glycosylation of Asn-594. COX-1 and COX-2 are found in abundance on the luminal surfaces of the ER and inner membrane of the nuclear envelope. Using confocal immunocytofluorescence, we detected both COX-2 and microsomal PGE synthase-1 (mPGES-1) but not COX-1 in the Golgi apparatus. Inhibition of trafficking between the ER and Golgi retarded COX-2 ERAD. COX-2 has a C-terminal STEL sequence, which is an inefficient ER retention signal. Substituting this sequence with KDEL, a robust ER retention signal, concentrated COX-2 in the ER where it was stable and slowly glycosylated on Asn-594. Native COX-2 and a recombinant COX-2 having a Golgi targeting signal but not native COX-1 exhibited efficient catalytic coupling to mPGES-1. We conclude that N-glycosylation of Asn-594 of COX-2 occurs in the ER, leading to anterograde movement of COX-2 to the Golgi where the Asn-594-linked glycan is trimmed prior to retrograde COX-2 transport to the ER for ERAD. Having an inefficient ER retention signal leads to sluggish Golgi to ER transit of COX-2. This permits significant Golgi residence time during which COX-2 can function catalytically. Cytosolic phospholipase A2α, which mobilizes arachidonic acid for PG synthesis, preferentially translocates to the Golgi in response to physiologic Ca(2+) mobilization. We propose that cytosolic phospholipase A2α, COX-2, and mPGES-1 in the Golgi comprise a dedicated system for COX-2-dependent PGE2 biosynthesis.
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Affiliation(s)
- Chong Yuan
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - William L Smith
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109
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19
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rCNT2 extracellular cysteines, Cys615
and Cys649
, are important for maturation and sorting to the plasma membrane. FEBS Lett 2014; 588:4382-9. [DOI: 10.1016/j.febslet.2014.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/27/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
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20
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Ninagawa S, Okada T, Sumitomo Y, Kamiya Y, Kato K, Horimoto S, Ishikawa T, Takeda S, Sakuma T, Yamamoto T, Mori K. EDEM2 initiates mammalian glycoprotein ERAD by catalyzing the first mannose trimming step. ACTA ACUST UNITED AC 2014; 206:347-56. [PMID: 25092655 PMCID: PMC4121980 DOI: 10.1083/jcb.201404075] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
All three mammalian EDEM family members possess mannosidase activity and are necessary for glycoprotein degradation, but EDEM2 performs a unique, rate-limiting, first mannose trimming step upstream of EDEM1 and EDEM3. Glycoproteins misfolded in the endoplasmic reticulum (ER) are subjected to ER-associated glycoprotein degradation (gpERAD) in which Htm1-mediated mannose trimming from the oligosaccharide Man8GlcNAc2 to Man7GlcNAc2 is the rate-limiting step in yeast. In contrast, the roles of the three Htm1 homologues (EDEM1/2/3) in mammalian gpERAD have remained elusive, with a key controversy being whether EDEMs function as mannosidases or as lectins. We therefore conducted transcription activator-like effector nuclease–mediated gene knockout analysis in human cell line and found that all endogenous EDEMs possess mannosidase activity. Mannose trimming from Man8GlcNAc2 to Man7GlcNAc2 is performed mainly by EDEM3 and to a lesser extent by EDEM1. Most surprisingly, the upstream mannose trimming from Man9GlcNAc2 to Man8GlcNAc2 is conducted mainly by EDEM2, which was previously considered to lack enzymatic activity. Based on the presence of two rate-limiting steps in mammalian gpERAD, we propose that mammalian cells double check gpERAD substrates before destruction by evolving EDEM2, a novel-type Htm1 homologue that catalyzes the first mannose trimming step from Man9GlcNAc2.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
| | - Tetsuya Okada
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
| | - Yoshiki Sumitomo
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
| | - Yukiko Kamiya
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
| | - Koichi Kato
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Satoshi Horimoto
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
| | - Tokiro Ishikawa
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
| | - Shunichi Takeda
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, and Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8502, Japan
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21
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Yamaguchi T, Sakae Y, Zhang Y, Yamamoto S, Okamoto Y, Kato K. Exploration of conformational spaces of high-mannose-type oligosaccharides by an NMR-validated simulation. Angew Chem Int Ed Engl 2014; 53:10941-4. [PMID: 25196214 DOI: 10.1002/anie.201406145] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Indexed: 12/11/2022]
Abstract
Exploration of the conformational spaces of flexible biomacromolecules is essential for quantitatively understanding the energetics of their molecular recognition processes. We employed stable isotope- and lanthanide-assisted NMR approaches in conjunction with replica-exchange molecular dynamics (REMD) simulations to obtain atomic descriptions of the conformational dynamics of high-mannose-type oligosaccharides, which harbor intracellular glycoprotein-fate determinants in their triantennary structures. The experimentally validated REMD simulation provided quantitative views of the dynamic conformational ensembles of the complicated, branched oligosaccharides, and indicated significant expansion of the conformational space upon removal of a terminal mannose residue during the functional glycan-processing pathway.
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Affiliation(s)
- Takumi Yamaguchi
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787 (Japan); Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603 (Japan); School of Physical Sciences, The Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787 (Japan)
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22
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Yamaguchi T, Sakae Y, Zhang Y, Yamamoto S, Okamoto Y, Kato K. Exploration of Conformational Spaces of High-Mannose-Type Oligosaccharides by an NMR-Validated Simulation. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Dersh D, Jones SM, Eletto D, Christianson JC, Argon Y. OS-9 facilitates turnover of nonnative GRP94 marked by hyperglycosylation. Mol Biol Cell 2014; 25:2220-34. [PMID: 24899641 PMCID: PMC4116297 DOI: 10.1091/mbc.e14-03-0805] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
ER quality control factors GRP94 and OS-9 associate not for the disposal of ERAD substrates but
instead because OS-9 sequesters and degrades aberrant forms of GRP94, which are hyperglycosylated at
cryptic acceptor sites and have altered structure and activity. This highlights a novel mechanism of
quality control of an ER-resident chaperone. The tight coupling of protein folding pathways with disposal mechanisms promotes the efficacy of
protein production in the endoplasmic reticulum (ER). It has been hypothesized that the ER-resident
molecular chaperone glucose-regulated protein 94 (GRP94) is part of this quality control coupling
because it supports folding of select client proteins yet also robustly associates with the lectin
osteosarcoma amplified 9 (OS-9), a component involved in ER-associated degradation (ERAD). To
explore this possibility, we investigated potential functions for the GRP94/OS-9 complex in ER
quality control. Unexpectedly, GRP94 does not collaborate with OS-9 in ERAD of misfolded substrates,
nor is the chaperone required directly for OS-9 folding. Instead, OS-9 binds preferentially to a
subpopulation of GRP94 that is hyperglycosylated on cryptic N-linked glycan acceptor sites.
Hyperglycosylated GRP94 forms have nonnative conformations and are less active. As a result, these
species are degraded much faster than the major, monoglycosylated form of GRP94 in an
OS-9–mediated, ERAD-independent, lysosomal-like mechanism. This study therefore clarifies
the role of the GRP94/OS-9 complex and describes a novel pathway by which glycosylation of cryptic
acceptor sites influences the function and fate of an ER-resident chaperone.
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Affiliation(s)
- Devin Dersh
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Stephanie M Jones
- Ludwig Institute for Cancer Research, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Davide Eletto
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - John C Christianson
- Ludwig Institute for Cancer Research, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Suzuki T, Harada Y. Non-lysosomal degradation pathway for N-linked glycans and dolichol-linked oligosaccharides. Biochem Biophys Res Commun 2014; 453:213-9. [PMID: 24866240 DOI: 10.1016/j.bbrc.2014.05.075] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 05/16/2014] [Indexed: 01/11/2023]
Abstract
There is growing evidence that asparagine (N)-linked glycans play pivotal roles in protein folding and intra- or intercellular trafficking of N-glycosylated proteins. During the N-glycosylation of proteins, significant amounts of free oligosaccharides (fOSs) and phosphorylated oligosaccharides (POSs) are generated at the endoplasmic reticulum (ER) membrane by unclarified mechanisms. fOSs are also formed in the cytosol by the enzymatic deglycosylation of misfolded glycoproteins destined for proteasomal degradation. This article summarizes the current knowledge of the molecular and regulatory mechanisms underlying the formation of fOSs and POSs in mammalian cells and Saccharomyces cerevisiae.
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Affiliation(s)
- Tadashi Suzuki
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Japan.
| | - Yoichiro Harada
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, RIKEN Global Research Cluster, Japan
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Liu Y, Li J. Endoplasmic reticulum-mediated protein quality control in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2014; 5:162. [PMID: 24817869 PMCID: PMC4012192 DOI: 10.3389/fpls.2014.00162] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 04/07/2014] [Indexed: 05/19/2023]
Abstract
A correct three-dimensional structure is crucial for the physiological functions of a protein, yet the folding of proteins to acquire native conformation is a fundamentally error-prone process. Eukaryotic organisms have evolved a highly conserved endoplasmic reticulum-mediated protein quality control (ERQC) mechanism to monitor folding processes of secretory and membrane proteins, allowing export of only correctly folded proteins to their physiological destinations, retaining incompletely/mis-folded ones in the ER for additional folding attempts, marking and removing terminally misfolded ones via a unique multiple-step degradation process known as ER-associated degradation (ERAD). Most of our current knowledge on ERQC and ERAD came from genetic and biochemical investigations in yeast and mammalian cells. Recent studies in the reference plant Arabidopsis thaliana uncovered homologous components and similar mechanisms in plants for monitoring protein folding and for retaining, repairing, and removing misfolded proteins. These studies also revealed critical roles of the plant ERQC/ERAD systems in regulating important biochemical/physiological processes, such as abiotic stress tolerance and plant defense. In this review, we discuss our current understanding about the molecular components and biochemical mechanisms of the plant ERQC/ERAD system in comparison to yeast and mammalian systems.
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Affiliation(s)
| | - Jianming Li
- *Correspondence: Jianming Li, Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4085 Natural Science Building, 830 North University, Ann Arbor, MI 48109-1048, USA e-mail:
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MHC class I molecules are preferentially ubiquitinated on endoplasmic reticulum luminal residues during HRD1 ubiquitin E3 ligase-mediated dislocation. Proc Natl Acad Sci U S A 2013; 110:14290-5. [PMID: 23929775 DOI: 10.1073/pnas.1303380110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Misfolded MHC class I heavy chains (MHC I HCs) are targeted for endoplasmic reticulum (ER)-associated degradation (ERAD) by the ubiquitin E3 ligase HRD1, and E2 ubiquitin conjugating enzyme UBE2J1, and represent one of the few known endogenous ERAD substrates. The mechanism by which misfolded proteins are dislocated across the ER membrane into the cytosol is unclear. Here, we investigate the requirements for MHC I ubiquitination and degradation and show that endogenous misfolded MHC I HCs are recognized in the ER lumen by EDEM1 in a glycan-dependent manner and targeted to the core SEL1L/HRD1/UBE2J1 complex. A soluble MHC I HC lacking its transmembrane domain and cytosolic tail uses the same ERAD components and is degraded as efficiently as wild-type MHC I. Unexpectedly, HRD1-dependent polyubiquitination is preferentially targeted to the ER luminal domain of full-length MHC I HCs, despite the presence of an exposed cytosolic C-terminal tail. MHC I luminal domain ubiquitination occurs before p97 ATPase-mediated extraction from the ER membrane and can be targeted to nonlysine, as well as lysine, residues. A subset of integral membrane proteins, therefore, requires an early dislocation event to expose part of their luminal domain to the cytosol, before HRD1-mediated polyubiquitination and dislocation.
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Matsushima H, Hirano M, Ito Y, Totani K. Diverse Effects of Macromolecular Crowding on the Sequential Glycan-Processing Pathway Involved in Glycoprotein Quality Control. Chembiochem 2013; 14:753-8. [DOI: 10.1002/cbic.201300028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Indexed: 12/20/2022]
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Fujimori T, Kamiya Y, Nagata K, Kato K, Hosokawa N. Endoplasmic reticulum lectin XTP3-B inhibits endoplasmic reticulum-associated degradation of a misfolded α1-antitrypsin variant. FEBS J 2013; 280:1563-75. [DOI: 10.1111/febs.12157] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 12/21/2012] [Accepted: 01/22/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Tsutomu Fujimori
- Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences; Kyoto University; Japan
| | | | - Kazuhiro Nagata
- Laboratory of Molecular and Cellular Biology, Faculty of Life Sciences; Kyoto Sangyo University; Japan
| | | | - Nobuko Hosokawa
- Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences; Kyoto University; Japan
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Iwamoto S, Isoyama M, Hirano M, Yamaya K, Ito Y, Matsuo I, Totani K. Reconstructed glycan profile for evaluation of operating status of the endoplasmic reticulum glycoprotein quality control. Glycobiology 2012; 23:121-31. [DOI: 10.1093/glycob/cws130] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Su W, Liu Y, Xia Y, Hong Z, Li J. The Arabidopsis homolog of the mammalian OS-9 protein plays a key role in the endoplasmic reticulum-associated degradation of misfolded receptor-like kinases. MOLECULAR PLANT 2012; 5:929-40. [PMID: 22516478 PMCID: PMC3399701 DOI: 10.1093/mp/sss042] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 05/18/2023]
Abstract
The endoplasmic reticulum-associated degradation (ERAD) is a highly conserved mechanism to remove misfolded membrane/secretory proteins from the endoplasmic reticulum (ER). While many of the individual components of the ERAD machinery are well characterized in yeast and mammals, our knowledge of a plant ERAD process is rather limited. Here, we report a functional study of an Arabidopsis homolog (AtOS9) of an ER luminal lectin Yos9 (OS-9 in mammals) that recognizes a unique asparagine-linked glycan on misfolded proteins. We discovered that AtOS9 is an ER-localized glycoprotein that is co-expressed with many known/predicted ER chaperones. A T-DNA insertional atos9-t mutation blocks the degradation of a structurally imperfect yet biochemically competent brassinosteroid (BR) receptor bri1-9, causing its increased accumulation in the ER and its consequent leakage to the cell surface responsible for restoring the BR sensitivity and suppressing the dwarfism of the bri1-9 mutant. In addition, we identified a missense mutation in AtOS9 in a recently discovered ERAD mutant ems-mutagenized bri1 suppressor 6 (ebs6-1). Moreover, we showed that atos9-t also inhibits the ERAD of bri1-5, another ER-retained BR receptor, and a misfolded EFR, a BRI1-like receptor for the bacterial translation elongation factor EF-Tu. Furthermore, we found that AtOS9 interacted biochemically and genetically with EBS5, an Arabidopsis homolog of the yeast Hrd3/mammalian Sel1L known to collaborate with Yos9/OS-9 to select ERAD clients. Taken together, our results demonstrated a functional role of AtOS9 in a plant ERAD process that degrades misfolded receptor-like kinases.
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Affiliation(s)
- Wei Su
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109–1048, USA
- Present address: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Yidan Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109–1048, USA
| | - Yang Xia
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109–1048, USA
| | - Zhi Hong
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109–1048, USA
- Present address: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Jianming Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109–1048, USA
- To whom correspondence should be addressed. E-mail , tel. +1-734-763-4253; fax +1-734-647-0884
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Hüttner S, Veit C, Schoberer J, Grass J, Strasser R. Unraveling the function of Arabidopsis thaliana OS9 in the endoplasmic reticulum-associated degradation of glycoproteins. PLANT MOLECULAR BIOLOGY 2012; 79:21-33. [PMID: 22328055 PMCID: PMC3332353 DOI: 10.1007/s11103-012-9891-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/29/2012] [Indexed: 05/18/2023]
Abstract
In the endoplasmic reticulum, immature polypeptides coincide with terminally misfolded proteins. Consequently, cells need a well-balanced quality control system, which decides about the fate of individual proteins and maintains protein homeostasis. Misfolded and unassembled proteins are sent for destruction via the endoplasmic reticulum-associated degradation (ERAD) machinery to prevent the accumulation of potentially toxic protein aggregates. Here, we report the identification of Arabidopsis thaliana OS9 as a component of the plant ERAD pathway. OS9 is an ER-resident glycoprotein containing a mannose-6-phosphate receptor homology domain, which is also found in yeast and mammalian lectins involved in ERAD. OS9 fused to the C-terminal domain of YOS9 can complement the ERAD defect of the corresponding yeast Δyos9 mutant. An A. thaliana OS9 loss-of-function line suppresses the severe growth phenotype of the bri1-5 and bri1-9 mutant plants, which harbour mutated forms of the brassinosteroid receptor BRI1. Co-immunoprecipitation studies demonstrated that OS9 associates with Arabidopsis SEL1L/HRD3, which is part of the plant ERAD complex and with the ERAD substrates BRI1-5 and BRI1-9, but only the binding to BRI1-5 occurs in a glycan-dependent way. OS9-deficiency results in activation of the unfolded protein response and reduces salt tolerance, highlighting the role of OS9 during ER stress. We propose that OS9 is a component of the plant ERAD machinery and may act specifically in the glycoprotein degradation pathway.
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Affiliation(s)
- Silvia Hüttner
- Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Christiane Veit
- Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Jennifer Schoberer
- Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
- Present Address: Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP UK
| | - Josephine Grass
- Department of Chemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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Izawa T, Nagai H, Endo T, Nishikawa SI. Yos9p and Hrd1p mediate ER retention of misfolded proteins for ER-associated degradation. Mol Biol Cell 2012; 23:1283-93. [PMID: 22298424 PMCID: PMC3315801 DOI: 10.1091/mbc.e11-08-0722] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Yos9p is involved in ER-associated degradation (ERAD) of misfolded glycoproteins. This study shows that Yos9p is required for ER retention of ERAD substrates by targeting them to the Hrd1p E3 ligase. This ER retention is independent of the glycan degradation signal on substrates and is separable from the later degradation step. The endoplasmic reticulum (ER) has an elaborate quality control system, which retains misfolded proteins and targets them to ER-associated protein degradation (ERAD). To analyze sorting between ER retention and ER exit to the secretory pathway, we constructed fusion proteins containing both folded carboxypeptidase Y (CPY) and misfolded mutant CPY (CPY*) units. Although the luminal Hsp70 chaperone BiP interacts with the fusion proteins containing CPY* with similar efficiency, a lectin-like ERAD factor Yos9p binds to them with different efficiency. Correlation between efficiency of Yos9p interactions and ERAD of these fusion proteins indicates that Yos9p but not BiP functions in the retention of misfolded proteins for ERAD. Yos9p targets a CPY*-containing ERAD substrate to Hrd1p E3 ligase, thereby causing ER retention of the misfolded protein. This ER retention is independent of the glycan degradation signal on the misfolded protein and operates even when proteasomal degradation is inhibited. These results collectively indicate that Yos9p and Hrd1p mediate ER retention of misfolded proteins in the early stage of ERAD, which constitutes a process separable from the later degradation step.
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Affiliation(s)
- Toshiaki Izawa
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
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Kamiya Y, Satoh T, Kato K. Molecular and structural basis for N-glycan-dependent determination of glycoprotein fates in cells. Biochim Biophys Acta Gen Subj 2012; 1820:1327-37. [PMID: 22240168 DOI: 10.1016/j.bbagen.2011.12.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 12/27/2011] [Accepted: 12/27/2011] [Indexed: 11/18/2022]
Abstract
BACKGROUND N-linked oligosaccharides operate as tags for protein quality control, consigning glycoproteins to different fates, i.e. folding in the endoplasmic reticulum (ER), vesicular transport between the ER and the Golgi complex, and ER-associated degradation of glycoproteins, by interacting with a panel of intracellular lectins in the early secretory pathway. SCOPE OF REVIEW This review summarizes the current state of knowledge regarding the molecular and structural basis for glycoprotein-fate determination in cells that is achieved through the actions of the intracellular lectins and its partner proteins. MAJOR CONCLUSIONS Cumulative frontal affinity chromatography (FAC) data demonstrated that the intracellular lectins exhibit distinct sugar-binding specificity profiles. The glycotopes recognized by these lectins as fate determinants are embedded in the triantennary structures of the high-mannose-type oligosaccharides and are exposed upon trimming of the outer glucose and mannose residues during the N-glycan processing pathway. Furthermore, recently emerged 3D structural data offer mechanistic insights into functional interplay between an intracellular lectin and its binding partner in the early secretory pathway. GENERAL SIGNIFICANCE Structural biology approaches in conjunction with FAC methods provide atomic pictures of the mechanisms behind the glycoprotein-fate determination in cells. This article is a part of a Special issue entitled: Glycoproteomics.
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Affiliation(s)
- Yukiko Kamiya
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
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Endoplasmic reticulum-associated degradation (ERAD) of misfolded glycoproteins and mutant P23H rhodopsin in photoreceptor cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:559-65. [PMID: 22183378 DOI: 10.1007/978-1-4614-0631-0_71] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Hüttner S, Strasser R. Endoplasmic reticulum-associated degradation of glycoproteins in plants. FRONTIERS IN PLANT SCIENCE 2012; 3:67. [PMID: 22645596 PMCID: PMC3355801 DOI: 10.3389/fpls.2012.00067] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 03/21/2012] [Indexed: 05/20/2023]
Abstract
In all eukaryotes the endoplasmic reticulum (ER) has a central role in protein folding and maturation of secretory and membrane proteins. Upon translocation into the ER polypeptides are immediately subjected to folding and modifications involving the formation of disulfide bridges, assembly of subunits to multi-protein complexes, and glycosylation. During these processes incompletely folded, terminally misfolded, and unassembled proteins can accumulate which endanger the cellular homeostasis and subsequently the survival of cells and tissues. Consequently, organisms have developed a quality control system to cope with this problem and remove the unwanted protein load from the ER by a process collectively referred to as ER-associated degradation (ERAD) pathway. Recent studies in Arabidopsis have identified plant ERAD components involved in the degradation of aberrant proteins and evidence was provided for a specific role in abiotic stress tolerance. In this short review we discuss our current knowledge about this important cellular pathway.
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Affiliation(s)
- Silvia Hüttner
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life SciencesVienna, Austria
- *Correspondence: Richard Strasser, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria. e-mail:
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Satoh T. Molecular and Structural Basis for Sugar Recognition by Mannose 6-Phosphate Receptor Homology Domain-Containing Lectins and Proteins. TRENDS GLYCOSCI GLYC 2012. [DOI: 10.4052/tigg.24.193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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37
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Lakhtin V, Lakhtin M, Alyoshkin V. Lectins of living organisms. The overview. Anaerobe 2011; 17:452-5. [DOI: 10.1016/j.anaerobe.2011.06.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
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Abstract
The endoplasmic reticulum (ER) uses an elaborate surveillance system called the ER quality control (ERQC) system. The ERQC facilitates folding and modification of secretory and membrane proteins and eliminates terminally misfolded polypeptides through ER-associated degradation (ERAD) or autophagic degradation. This mechanism of ER protein surveillance is closely linked to redox and calcium homeostasis in the ER, whose balance is presumed to be regulated by a specific cellular compartment. The potential to modulate proteostasis and metabolism with chemical compounds or targeted siRNAs may offer an ideal option for the treatment of disease.
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Pabst M, Grass J, Toegel S, Liebminger E, Strasser R, Altmann F. Isomeric analysis of oligomannosidic N-glycans and their dolichol-linked precursors. Glycobiology 2011; 22:389-99. [DOI: 10.1093/glycob/cwr138] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Martinez Benitez E, Stolz A, Becher A, Wolf DH. Mnl2, a novel component of the ER associated protein degradation pathway. Biochem Biophys Res Commun 2011; 414:528-32. [DOI: 10.1016/j.bbrc.2011.09.100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 09/20/2011] [Indexed: 11/26/2022]
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Ron E, Shenkman M, Groisman B, Izenshtein Y, Leitman J, Lederkremer GZ. Bypass of glycan-dependent glycoprotein delivery to ERAD by up-regulated EDEM1. Mol Biol Cell 2011; 22:3945-54. [PMID: 21917589 PMCID: PMC3204057 DOI: 10.1091/mbc.e10-12-0944] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Extensive trimming of mannose residues targets a misfolded glycoprotein for endoplasmic reticulum–associated degradation (ERAD). Surprisingly, overexpression of EDEM1 or its up-regulation by the unfolded protein response bypasses this requirement. Delivery to OS9 in the ER-derived quality control compartment and ERAD becomes mannose trimming–independent, accelerating glycoprotein disposal. Trimming of mannose residues from the N-linked oligosaccharide precursor is a stringent requirement for glycoprotein endoplasmic reticulum (ER)-associated degradation (ERAD). In this paper, we show that, surprisingly, overexpression of ER degradation–enhancing α-mannosidase-like protein 1 (EDEM1) or its up-regulation by IRE1, as occurs in the unfolded protein response, overrides this requirement and renders unnecessary the expression of ER mannosidase I. An EDEM1 deletion mutant lacking most of the carbohydrate-recognition domain also accelerated ERAD, delivering the substrate to XTP3-B and OS9. EDEM1 overexpression also accelerated the degradation of a mutant nonglycosylated substrate. Upon proteasomal inhibition, EDEM1 concentrated together with the ERAD substrate in the pericentriolar ER-derived quality control compartment (ERQC), where ER mannosidase I and ERAD machinery components are localized, including, as we show here, OS9. We suggest that a nascent glycoprotein can normally dissociate from EDEM1 and be rescued from ERAD by reentering calnexin-refolding cycles, a condition terminated by mannose trimming. At high EDEM1 levels, glycoprotein release is prevented and glycan interactions are no longer required, canceling the otherwise mandatory ERAD timing by mannose trimming and accelerating the targeting to degradation.
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Affiliation(s)
- Efrat Ron
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Dual regulation of the transcriptional activity of Nrf1 by β-TrCP- and Hrd1-dependent degradation mechanisms. Mol Cell Biol 2011; 31:4500-12. [PMID: 21911472 DOI: 10.1128/mcb.05663-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A growing body of evidence suggests that Nrf1 is an inducible transcription factor that maintains cellular homeostasis. Under physiological conditions, Nrf1 is targeted to the endoplasmic reticulum (ER), implying that it translocates into the nucleus in response to an activating signal. However, the molecular mechanisms by which the function of Nrf1 is modulated remain poorly understood. Here, we report that two distinct degradation mechanisms regulate Nrf1 activity and the expression of its target genes. In the nucleus, β-TrCP, an adaptor for the SCF (Skp1-Cul1-F-box protein) ubiquitin ligase, promotes the degradation of Nrf1 by catalyzing its polyubiquitination. This activity requires a DSGLS motif on Nrf1, which is similar to the canonical β-TrCP recognition motif. The short interfering RNA (siRNA)-mediated silencing of β-TrCP markedly augments the expression of Nrf1 target genes, such as the proteasome subunit PSMC4, indicating that β-TrCP represses Nrf1 activation. Meanwhile, in the cytoplasm, Nrf1 is degraded and suppressed by the ER-associated degradation (ERAD) ubiquitin ligase Hrd1 and valosin-containing protein (VCP) under normal conditions. We identified a cytoplasmic degradation motif on Nrf1 between the NHB1 and NHB2 domains that exhibited species conservation. Thus, these results clearly suggest that both β-TrCP- and Hrd1-dependent degradation mechanisms regulate the transcriptional activity of Nrf1 to maintain cellular homeostasis.
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Benitez EM, Stolz A, Wolf DH. Yos9, a control protein for misfolded glycosylated and non-glycosylated proteins in ERAD. FEBS Lett 2011; 585:3015-9. [PMID: 21871892 DOI: 10.1016/j.febslet.2011.08.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/08/2011] [Accepted: 08/16/2011] [Indexed: 11/24/2022]
Abstract
The endoplasmic reticulum (ER) is responsible for folding and delivery of secretory proteins to their site of action. One major modification proteins undergo in this organelle is N-glycosylation. Proteins that cannot fold properly will be directed to a process known as endoplasmic reticulum associated degradation (ERAD). Processing of N-glycans generates a signal for ERAD. The lectin Yos9 recognizes the N-glycan signal of misfolded proteins and acts as a gatekeeper for the delivery of these substrates to the cytoplasm for degradation. Presence of Yos9 accelerates degradation of the glycosylated model ERAD substrate CPY∗. Here we show that Yos9 has also a control function in degradation of the unglycosylated ERAD substrate CPY∗0000. It decelerates its degradation rate.
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Castonguay AC, Olson LJ, Dahms NM. Mannose 6-phosphate receptor homology (MRH) domain-containing lectins in the secretory pathway. Biochim Biophys Acta Gen Subj 2011; 1810:815-26. [PMID: 21723917 DOI: 10.1016/j.bbagen.2011.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/13/2011] [Accepted: 06/15/2011] [Indexed: 12/22/2022]
Abstract
BACKGROUND The mannose 6-phosphate receptor homology (MRH) domain-containing family of proteins, which include recycling receptors (mannose 6-phosphate receptors, MPRs), resident endoplasmic reticulum (ER) proteins (glucosidase II β-subunit, XTP3-B, OS-9), and a Golgi glycosyltransferase (GlcNAc-phosphotransferase γ-subunit), are characterized by the presence of one or more MRH domains. Many MRH domains act as lectins and bind specific phosphorylated (MPRs) or non-phosphorylated (glucosidase II β-subunit, XTP3-B and OS-9) high mannose-type N-glycans. The MPRs are the only proteins known to bind mannose 6-phosphate (Man-6-P) residues via their MRH domains. SCOPE OF REVIEW Recent biochemical and structural studies that have provided valuable insight into the glycan specificity and mechanisms of carbohydrate recognition by this diverse group of MRH domain-containing proteins are highlighted. MAJOR CONCLUSIONS Currently, three-dimensional structures are known for ten MRH domains, revealing the conservation of a similar fold. OS-9 and the MPRs use the same four residues (Gln, Arg, Glu, and Tyr) to bind mannose. GENERAL SIGNIFICANCE The MRH domain-containing proteins play key roles in the secretory pathway: glucosidase II, XTP3-B, and OS-9 are involved in the recognition of nascent glycoproteins, whereas the MPRs play an essential role in lysosome biogenesis by targeting Man-6-P-containing lysosomal enzymes to the lysosome.
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Affiliation(s)
- Alicia C Castonguay
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Iida Y, Fujimori T, Okawa K, Nagata K, Wada I, Hosokawa N. SEL1L protein critically determines the stability of the HRD1-SEL1L endoplasmic reticulum-associated degradation (ERAD) complex to optimize the degradation kinetics of ERAD substrates. J Biol Chem 2011; 286:16929-16939. [PMID: 21454652 PMCID: PMC3089536 DOI: 10.1074/jbc.m110.215871] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 03/13/2011] [Indexed: 08/03/2023] Open
Abstract
The mammalian HRD1-SEL1L complex provides a scaffold for endoplasmic reticulum (ER)-associated degradation (ERAD), thereby connecting luminal substrates for ubiquitination at the cytoplasmic surface after their retrotranslocation through the endoplasmic reticulum membrane. In this study the stability of the mammalian HRD1-SEL1L complex was assessed by performing siRNA-mediated knockdown of each of its components. Although endogenous SEL1L is a long-lived protein, the half-life of SEL1L was greatly reduced when HRD1 is silenced. Conversely, transiently expressed SEL1L was rapidly degraded but was stabilized when HRD1 was coexpressed. This was in contrast to the yeast Hrd1p-Hrd3p, where Hrd1p is destabilized by the depletion of Hrd3p, the SEL1L homologue. Endogenous HRD1-SEL1L formed a large ERAD complex (Complex I) associating with numerous ERAD components including ERAD lectin OS-9, membrane-spanning Derlin-1/2, VIMP, and Herp, whereas transiently expressed HRD1-SEL1L formed a smaller complex (Complex II) that was associated with OS-9 but not with Derlin-1/2, VIMP, or Herp. Despite its lack of stable association with the latter components, Complex II supported the retrotranslocation and degradation of model ERAD substrates α1-antitrypsin null Hong-Kong (NHK) and its variant NHK-QQQ lacking the N-glycosylation sites. NHK-QQQ was rapidly degraded when SEL1L was transiently expressed, whereas the simultaneous transfection of HRD1 diminished that effect. SEL1L unassociated with HRD1 was degraded by the ubiquitin-proteasome pathway, which suggests the involvement of a ubiquitin-ligase other than HRD1 in the rapid degradation of both SEL1L and NHK-QQQ. These results indicate that the regulation of the stability and assembly of the HRD1-SEL1L complex is critical to optimize the degradation kinetics of ERAD substrates.
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Affiliation(s)
- Yasutaka Iida
- From the Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8397, Japan
| | - Tsutomu Fujimori
- From the Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8397, Japan
| | - Katsuya Okawa
- Drug Discovery Research Laboratories, Kyowa Hakko Kirin Co. Ltd., 1188 Shimotogari, Nagaizumi-cho, Suntou-gun, Shizuoka 411-8731, Japan
| | - Kazuhiro Nagata
- the Laboratory of Molecular and Cellular Biology, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555, Japan, and
| | - Ikuo Wada
- the Department of Cell Sciences, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Nobuko Hosokawa
- From the Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8397, Japan
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Protein dislocation from the ER. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:925-36. [DOI: 10.1016/j.bbamem.2010.06.025] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 06/21/2010] [Accepted: 06/25/2010] [Indexed: 11/20/2022]
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Matsumoto A, Tateishi Y, Onoyama I, Okita Y, Nakayama K, Nakayama KI. Fbxw7β resides in the endoplasmic reticulum membrane and protects cells from oxidative stress. Cancer Sci 2011; 102:749-55. [PMID: 21205095 DOI: 10.1111/j.1349-7006.2011.01851.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Oxidative stress has been implicated in cancer initiation and progression. Fbxw7 (also known as Fbw7, SEL-10, hCdc4, or hAgo) is the F-box protein subunit of an Skp1-Cul1-F-box (SCF)-type ubiquitin ligase complex that plays a central role in the degradation of oncoproteins such as c-Myc, c-Jun, Notch, and cyclin E. Fbxw7 is therefore thought to function as a tumor suppressor, and indeed the Fbxw7 gene is frequently mutated in many human malignancies. The Fbxw7 gene locus encodes three protein isoforms: Fbxw7α, Fbxw7β, and Fbxw7γ. Whereas Fbxw7α and Fbxw7γ are resident in the nucleus, Fbxw7β shows a cytoplasmic distribution suggestive of localization to the endoplasmic reticulum (ER). The specific function of Fbxw7β has remained unknown, however. We now show that Fbxw7β contains a putative transmembrane domain near its NH(2) -terminus, and topological analysis revealed that Fbxw7β is inserted in the ER membrane. Fbxw7β assembled with Skp1, Cul1, and Rbx1 to form an SCF complex, although the efficiency of this process appeared lower than that for Fbxw7α or Fbxw7γ. To explore the physiological role of Fbxw7β, we generated mice specifically lacking this isoform of Fbxw7. Although these animals did not exhibit any apparent abnormalities in development, primary cultures of neurons prepared from the mutant mice were more vulnerable to oxidative stress than were those prepared from wild-type mice. Conversely, overexpression of Fbxw7β rendered cells resistant to oxidative stress, without affecting sensitivity to ER stress or other apoptosis-inducing agents. Our results thus suggest that Fbxw7β contributes to the protection of cells from oxidative stress.
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Affiliation(s)
- Akinobu Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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Protein Quality Control, Retention, and Degradation at the Endoplasmic Reticulum. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:197-280. [DOI: 10.1016/b978-0-12-386033-0.00005-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Structural Basis for Oligosaccharide Recognition of Misfolded Glycoproteins by OS-9 in ER-Associated Degradation. Mol Cell 2010; 40:905-16. [DOI: 10.1016/j.molcel.2010.11.017] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 07/24/2010] [Accepted: 09/24/2010] [Indexed: 11/21/2022]
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Miyagawa A, Totani K, Matsuo I, Ito Y. Promiscuous activity of ER glucosidase II discovered through donor specificity analysis of UGGT. Biochem Biophys Res Commun 2010; 403:322-8. [PMID: 21075077 DOI: 10.1016/j.bbrc.2010.11.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 11/08/2010] [Indexed: 10/18/2022]
Abstract
In glycoprotein quality control system in the endoplasmic reticulum (ER), UGGT (UDP-glucose:glycoprotein glucosyltransferase) and glucosidase II (G-II) play key roles. UGGT serves as a glycoprotein folding sensor by virtue of its unique specificity to glucosylate glycoproteins at incompletely folded stage. By using various UDP-Glc analogues, we first analyzed donor specificity of UGGT, which was proven to be rather narrow. However, marginal activity was observed with UDP-galactose and UDP-glucuronic acid as well as with 3-, 4- and 6-deoxy glucose analogues to give corresponding transfer products. Intriguingly, G-II smoothly converted all of them back to Man(9)GlcNAc(2), providing an indication that G-II has a promiscuous activity as a broad specificity hexosidase.
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Affiliation(s)
- Atsushi Miyagawa
- RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan.
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