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Zhang C, Shafaq-Zadah M, Pawling J, Hesketh GG, Dransart E, Pacholczyk K, Longo J, Gingras AC, Penn LZ, Johannes L, Dennis JW. SLC3A2 N-glycosylation and Golgi remodeling regulate SLC7A amino acid exchangers and stress mitigation. J Biol Chem 2023; 299:105416. [PMID: 37918808 PMCID: PMC10698284 DOI: 10.1016/j.jbc.2023.105416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
Proteostasis requires oxidative metabolism (ATP) and mitigation of the associated damage by glutathione, in an increasingly dysfunctional relationship with aging. SLC3A2 (4F2hc, CD98) plays a role as a disulfide-linked adaptor to the SLC7A5 and SLC7A11 exchangers which import essential amino acids and cystine while exporting Gln and Glu, respectively. The positions of N-glycosylation sites on SLC3A2 have evolved with the emergence of primates, presumably in synchrony with metabolism. Herein, we report that each of the four sites in SLC3A2 has distinct profiles of Golgi-modified N-glycans. N-glycans at the primate-derived site N381 stabilized SLC3A2 in the galectin-3 lattice against coated-pit endocytosis, while N365, the site nearest the membrane promoted glycolipid-galectin-3 (GL-Lect)-driven endocytosis. Our results indicate that surface retention and endocytosis are precisely balanced by the number, position, and remodeling of N-glycans on SLC3A2. Furthermore, proteomics and functional assays revealed an N-glycan-dependent clustering of the SLC3A2∗SLC7A5 heterodimer with amino-acid/Na+ symporters (SLC1A4, SLC1A5) that balances branched-chain amino acids and Gln levels, at the expense of ATP to maintain the Na+/K+ gradient. In replete conditions, SLC3A2 interactions require Golgi-modified N-glycans at N365D and N381D, whereas reducing N-glycosylation in the endoplasmic reticulum by fluvastatin treatment promoted the recruitment of CD44 and transporters needed to mitigate stress. Thus, SLC3A2 N-glycosylation and Golgi remodeling of the N-glycans have distinct roles in amino acids import for growth, maintenance, and metabolic stresses.
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Affiliation(s)
- Cunjie Zhang
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada
| | - Massiullah Shafaq-Zadah
- Cellular and Chemical Biology Unit, Institut Curie, INSERM U1143, CNRS UMR3666, PSL Research University, Paris, France
| | - Judy Pawling
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada
| | - Geoffrey G Hesketh
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada
| | - Estelle Dransart
- Cellular and Chemical Biology Unit, Institut Curie, INSERM U1143, CNRS UMR3666, PSL Research University, Paris, France
| | - Karina Pacholczyk
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada
| | - Joseph Longo
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Ludger Johannes
- Cellular and Chemical Biology Unit, Institut Curie, INSERM U1143, CNRS UMR3666, PSL Research University, Paris, France
| | - James W Dennis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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Bieberich E. Synthesis, Processing, and Function of N-Glycans in N-Glycoproteins. ADVANCES IN NEUROBIOLOGY 2023; 29:65-93. [PMID: 36255672 DOI: 10.1007/978-3-031-12390-0_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Many membrane-resident and secreted proteins, including growth factors and their receptors are N-glycosylated. The initial N-glycan structure is synthesized in the endoplasmic reticulum (ER) as a branched structure on a lipid anchor (dolicholpyrophosphate) and then co-translationally, "en bloc" transferred and linked via N-acetylglucosamine to asparagine within a specific N-glycosylation acceptor sequence of the nascent recipient protein. In the ER and then the Golgi apparatus, the N-linked glycan structure is modified by hydrolytic removal of sugar residues ("trimming") followed by re-glycosylation with additional sugar residues ("processing") such as galactose, fucose or sialic acid to form complex N-glycoproteins. While the sequence of the reactions leading to biosynthesis, "en bloc" transfer and processing of N-glycans is well investigated, it is still not completely understood how N-glycans affect the biological fate and function of N-glycoproteins. This review will discuss the biology of N-glycoprotein synthesis, processing and function with specific reference to the physiology and pathophysiology of the immune and nervous system, as well as infectious diseases such as Covid-19.
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Affiliation(s)
- Erhard Bieberich
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA.
- Veteran Affairs Medical Center, Lexington, KY, USA.
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Sun X, Guo C, Ali K, Zheng Q, Wei Q, Zhu Y, Wang L, Li G, Li W, Zheng B, Bai Q, Wu G. A Non-redundant Function of MNS5: A Class I α-1, 2 Mannosidase, in the Regulation of Endoplasmic Reticulum-Associated Degradation of Misfolded Glycoproteins. FRONTIERS IN PLANT SCIENCE 2022; 13:873688. [PMID: 35519817 PMCID: PMC9062699 DOI: 10.3389/fpls.2022.873688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/14/2022] [Indexed: 05/14/2023]
Abstract
Endoplasmic Reticulum-Associated Degradation (ERAD) is one of the major processes in maintaining protein homeostasis. Class I α-mannosidases MNS4 and MNS5 are involved in the degradation of misfolded variants of the heavily glycosylated proteins, playing an important role for glycan-dependent ERAD in planta. MNS4 and MNS5 reportedly have functional redundancy, meaning that only the loss of both MNS4 and MNS5 shows phenotypes. However, MNS4 is a membrane-associated protein while MNS5 is a soluble protein, and both can localize to the endoplasmic reticulum (ER). Furthermore, MNS4 and MNS5 differentially demannosylate the glycoprotein substrates. Importantly, we found that their gene expression patterns are complemented rather than overlapped. This raises the question of whether they indeed work redundantly, warranting a further investigation. Here, we conducted an exhaustive genetic screen for a suppressor of the bri1-5, a brassinosteroid (BR) receptor mutant with its receptor downregulated by ERAD, and isolated sbi3, a suppressor of bri1-5 mutant named after sbi1 (suppressor of bri1). After genetic mapping together with whole-genome re-sequencing, we identified a point mutation G343E in AT1G27520 (MNS5) in sbi3. Genetic complementation experiments confirmed that sbi3 was a loss-of-function allele of MNS5. In addition, sbi3 suppressed the dwarf phenotype of bri1-235 in the proteasome-independent ERAD pathway and bri1-9 in the proteasome-dependent ERAD pathway. Importantly, sbi3 could only affect BRI1/bri1 with kinase activities such that it restored BR-sensitivities of bri1-5, bri1-9, and bri1-235 but not null bri1. Furthermore, sbi3 was less tolerant to tunicamycin and salt than the wild-type plants. Thus, our study uncovers a non-redundant function of MNS5 in the regulation of ERAD as well as plant growth and ER stress response, highlighting a need of the traditional forward genetic approach to complement the T-DNA or CRISPR-Cas9 systems on gene functional study.
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Li H, Sun S. Protein Aggregation in the ER: Calm behind the Storm. Cells 2021; 10:cells10123337. [PMID: 34943844 PMCID: PMC8699410 DOI: 10.3390/cells10123337] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 02/06/2023] Open
Abstract
As one of the largest organelles in eukaryotic cells, the endoplasmic reticulum (ER) plays a vital role in the synthesis, folding, and assembly of secretory and membrane proteins. To maintain its homeostasis, the ER is equipped with an elaborate network of protein folding chaperones and multiple quality control pathways whose cooperative actions safeguard the fidelity of protein biogenesis. However, due to genetic abnormalities, the error-prone nature of protein folding and assembly, and/or defects or limited capacities of the protein quality control systems, nascent proteins may become misfolded and fail to exit the ER. If not cleared efficiently, the progressive accumulation of misfolded proteins within the ER may result in the formation of toxic protein aggregates, leading to the so-called “ER storage diseases”. In this review, we first summarize our current understanding of the protein folding and quality control networks in the ER, including chaperones, unfolded protein response (UPR), ER-associated protein degradation (ERAD), and ER-selective autophagy (ER-phagy). We then survey recent research progress on a few ER storage diseases, with a focus on the role of ER quality control in the disease etiology, followed by a discussion on outstanding questions and emerging concepts in the field.
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Affiliation(s)
- Haisen Li
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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Sun JL, Li JY, Wang MJ, Song ZT, Liu JX. Protein Quality Control in Plant Organelles: Current Progress and Future Perspectives. MOLECULAR PLANT 2021; 14:95-114. [PMID: 33137518 DOI: 10.1016/j.molp.2020.10.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/09/2020] [Accepted: 10/28/2020] [Indexed: 05/20/2023]
Abstract
The endoplasmic reticulum, chloroplasts, and mitochondria are major plant organelles for protein synthesis, photosynthesis, metabolism, and energy production. Protein homeostasis in these organelles, maintained by a balance between protein synthesis and degradation, is essential for cell functions during plant growth, development, and stress resistance. Nucleus-encoded chloroplast- and mitochondrion-targeted proteins and ER-resident proteins are imported from the cytosol and undergo modification and maturation within their respective organelles. Protein folding is an error-prone process that is influenced by both developmental signals and environmental cues; a number of mechanisms have evolved to ensure efficient import and proper folding and maturation of proteins in plant organelles. Misfolded or damaged proteins with nonnative conformations are subject to degradation via complementary or competing pathways: intraorganelle proteases, the organelle-associated ubiquitin-proteasome system, and the selective autophagy of partial or entire organelles. When proteins in nonnative conformations accumulate, the organelle-specific unfolded protein response operates to restore protein homeostasis by reducing protein folding demand, increasing protein folding capacity, and enhancing components involved in proteasome-associated protein degradation and autophagy. This review summarizes recent progress on the understanding of protein quality control in the ER, chloroplasts, and mitochondria in plants, with a focus on common mechanisms shared by these organelles during protein homeostasis.
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Affiliation(s)
- Jing-Liang Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Jin-Yu Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Mei-Jing Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Ze-Ting Song
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
| | - Jian-Xiang Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310027, China.
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The Role of Endoplasmic Reticulum Chaperones in Protein Folding and Quality Control. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:27-50. [PMID: 34050861 DOI: 10.1007/978-3-030-67696-4_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Molecular chaperones assist the folding of nascent chains in the cell. Chaperones also aid in quality control decisions as persistent chaperone binding can help to sort terminal misfolded proteins for degradation. There are two major molecular chaperone families in the endoplasmic reticulum (ER) that assist proteins in reaching their native structure and evaluating the fidelity of the maturation process. The ER Hsp70 chaperone, BiP, supports adenine nucleotide-regulated binding to non-native proteins that possess exposed hydrophobic regions. In contrast, the carbohydrate-dependent chaperone system involving the membrane protein calnexin and its soluble paralogue calreticulin recognize a specific glycoform of an exposed hydrophilic protein modification for which the composition is controlled by a series of glycosidases and transferases. Here, we compare and contrast the properties, mechanisms of action and functions of these different chaperones systems that work in parallel, as well as together, to assist a large variety of substrates that traverse the eukaryotic secretory pathway.
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Ninagawa S, George G, Mori K. Mechanisms of productive folding and endoplasmic reticulum-associated degradation of glycoproteins and non-glycoproteins. Biochim Biophys Acta Gen Subj 2020; 1865:129812. [PMID: 33316349 DOI: 10.1016/j.bbagen.2020.129812] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The quality of proteins destined for the secretory pathway is ensured by two distinct mechanisms in the endoplasmic reticulum (ER): productive folding of newly synthesized proteins, which is assisted by ER-localized molecular chaperones and in most cases also by disulfide bond formation and transfer of an oligosaccharide unit; and ER-associated degradation (ERAD), in which proteins unfolded or misfolded in the ER are recognized and processed for delivery to the ER membrane complex, retrotranslocated through the complex with simultaneous ubiquitination, extracted by AAA-ATPase to the cytosol, and finally degraded by the proteasome. SCOPE OF REVIEW We describe the mechanisms of productive folding and ERAD, with particular attention to glycoproteins versus non-glycoproteins, and to yeast versus mammalian systems. MAJOR CONCLUSION Molecular mechanisms of the productive folding of glycoproteins and non-glycoproteins mediated by molecular chaperones and protein disulfide isomerases are well conserved from yeast to mammals. Additionally, mammals have gained an oligosaccharide structure-dependent folding cycle for glycoproteins. The molecular mechanisms of ERAD are also well conserved from yeast to mammals, but redundant expression of yeast orthologues in mammals has been encountered, particularly for components involved in recognition and processing of glycoproteins and components of the ER membrane complex involved in retrotranslocation and simultaneous ubiquitination of glycoproteins and non-glycoproteins. This may reflect an evolutionary consequence of increasing quantity or quality needs toward mammals. GENERAL SIGNIFICANCE The introduction of innovative genome editing technology into analysis of the mechanisms of mammalian ERAD, as exemplified here, will provide new insights into the pathogenesis of various diseases.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Ginto George
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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8
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Margolin E, Oh YJ, Verbeek M, Naude J, Ponndorf D, Meshcheriakova YA, Peyret H, van Diepen MT, Chapman R, Meyers AE, Lomonossoff GP, Matoba N, Williamson A, Rybicki EP. Co-expression of human calreticulin significantly improves the production of HIV gp140 and other viral glycoproteins in plants. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2109-2117. [PMID: 32096288 PMCID: PMC7540014 DOI: 10.1111/pbi.13369] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 05/19/2023]
Abstract
Plant molecular farming (PMF) is rapidly gaining traction as a viable alternative to the currently accepted paradigm of producing biologics. While the platform is potentially cheaper and more scalable than conventional manufacturing systems, expression yields and appropriate post-translational modifications along the plant secretory pathway remain a challenge for certain proteins. Viral fusion glycoproteins in particular are often expressed at low yields in plants and, in some cases, may not be appropriately processed. Recently, however, transiently or stably engineering the host plant has shown promise as a strategy for producing heterologous proteins with more complex maturation requirements. In this study we investigated the co-expression of a suite of human chaperones to improve the production of a human immunodeficiency virus (HIV) type 1 soluble gp140 vaccine candidate in Nicotiana benthamiana plants. The co-expression of calreticulin (CRT) resulted in a dramatic increase in Env expression and ameliorated the endoplasmic reticulum (ER) stress response - as evidenced by lower transcript abundance of representative stress-responsive genes. The co-expression of CRT similarly improved accumulation of glycoproteins from Epstein-Barr virus (EBV), Rift Valley fever virus (RVFV) and chikungunya virus (CHIKV), suggesting that the endogenous chaperone machinery may impose a bottleneck for their production. We subsequently successfully combined the co-expression of human CRT with the transient expression of human furin, to enable the production of an appropriately cleaved HIV gp140 antigen. These transient plant host engineering strategies are a promising approach for the production of high yields of appropriately processed and cleaved viral glycoproteins.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Youngjun J. Oh
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Matthew Verbeek
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Jason Naude
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Daniel Ponndorf
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | | | - Hadrien Peyret
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | - Michiel T. van Diepen
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | | | - Nobuyuki Matoba
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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Zhang C, Wang LL, Cao CY, Li N, Talukder M, Li JL. Selenium mitigates cadmium-induced crosstalk between autophagy and endoplasmic reticulum stress via regulating calcium homeostasis in avian leghorn male hepatoma (LMH) cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114613. [PMID: 32504893 DOI: 10.1016/j.envpol.2020.114613] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/12/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Cadmium (Cd) is a toxic heavy metal and widespread in environment and food, which is adverse to human and animal health. Food intervention is a hot topic because it has no side effects. Selenium (Se) is an essential trace element, found in various fruits and vegetables. Many previous papers have described that Se showed ameliorative effects against Cd. However, the underlying mechanism of antagonistic effect of Se against Cd-induced cytotoxicity in avian leghorn male hepatoma (LMH) cells is unknown, the molecular mechanism of Se antagonistic effect on Cd-induced and calcium (Ca2+) homeostasis disorder and crosstalk of ER stress and autophagy remain to be explored. In order to confirm the antagonistic effect of Se on Cd-induced LMH cell toxicity, LMH cells were treated with CdCl2 (2.5 μM) and Na2SeO3 (1.25 and 2.5 μM) for 24 h. In this study, Cd exposure induced cell death, disrupted intracellular Ca2+ homeostasis and Ca2+ homeostasis related regulatory factors, interfered with the cycle of cadherin (CNX)/calreticulin (CRT), and triggered ER stress and autophagy. Se intervention inhibited Cd-induced LDH release and crosstalk of ER stress and autophagy via regulating intracellular Ca2+ homeostasis. Moreover, Se mitigated Cd-induced Intracellular Ca2+ overload by Ca2+/calmodulin (CaM)/calmodulin kinase IV (CaMK-IV) signaling pathway. Herein, CNX/CRT cycle played a critical role for the protective effect of Se on Cd-induced hepatotoxicity. Based on these findings, we demonstrated that the application of Se is beneficial for prevention and alleviation of Cd toxicity.
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Affiliation(s)
- Cong Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; College of Animal Science and Veterinary Medcine, Henan Agricultural University, Zhengzhou, 450046 Henan, PR China
| | - Li-Li Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Chang-Yu Cao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; College of Life Science, Foshan University, Foshan, 528231, Guangdong, PR China
| | - Nan Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; National Research Institute for Family Planning, Beijing, 100081, PR China
| | - Milton Talukder
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Department of Physiology and Pharmacology, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Barishal, 8210, Bangladesh
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin, 150030, PR China; Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
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Shrimal S, Cherepanova NA, Mandon EC, Venev SV, Gilmore R. Asparagine-linked glycosylation is not directly coupled to protein translocation across the endoplasmic reticulum in Saccharomyces cerevisiae. Mol Biol Cell 2019; 30:2626-2638. [PMID: 31433728 PMCID: PMC6761772 DOI: 10.1091/mbc.e19-06-0330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mammalian cells express two oligosaccharyltransferase complexes, STT3A and STT3B, that have distinct roles in N-linked glycosylation. The STT3A complex interacts directly with the protein translocation channel to mediate glycosylation of proteins using an N-terminal-to-C-terminal scanning mechanism. N-linked glycosylation of proteins in budding yeast has been assumed to be a cotranslational reaction. We have compared glycosylation of several glycoproteins in yeast and mammalian cells. Prosaposin, a cysteine-rich protein that contains STT3A-dependent glycosylation sites, is poorly glycosylated in yeast cells and STT3A-deficient human cells. In contrast, a protein with extreme C-terminal glycosylation sites was efficiently glycosylated in yeast by a posttranslocational mechanism. Posttranslocational glycosylation was also observed for carboxypeptidase Y-derived reporter proteins that contain closely spaced acceptor sites. A comparison of two recent protein structures indicates that the yeast OST is unable to interact with the yeast heptameric Sec complex via an evolutionarily conserved interface due to occupation of the OST binding site by the Sec63 protein. The efficiency of glycosylation in yeast is not enhanced for proteins that are translocated by the Sec61 or Ssh1 translocation channels instead of the Sec complex. We conclude that N-linked glycosylation and protein translocation are not directly coupled in yeast cells.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Elisabet C Mandon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sergey V Venev
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
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Needham PG, Guerriero CJ, Brodsky JL. Chaperoning Endoplasmic Reticulum-Associated Degradation (ERAD) and Protein Conformational Diseases. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033928. [PMID: 30670468 DOI: 10.1101/cshperspect.a033928] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Misfolded proteins compromise cellular homeostasis. This is especially problematic in the endoplasmic reticulum (ER), which is a high-capacity protein-folding compartment and whose function requires stringent protein quality-control systems. Multiprotein complexes in the ER are able to identify, remove, ubiquitinate, and deliver misfolded proteins to the 26S proteasome for degradation in the cytosol, and these events are collectively termed ER-associated degradation, or ERAD. Several steps in the ERAD pathway are facilitated by molecular chaperone networks, and the importance of ERAD is highlighted by the fact that this pathway is linked to numerous protein conformational diseases. In this review, we discuss the factors that constitute the ERAD machinery and detail how each step in the pathway occurs. We then highlight the underlying pathophysiology of protein conformational diseases associated with ERAD.
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Affiliation(s)
- Patrick G Needham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | | | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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12
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Cherepanova NA, Venev SV, Leszyk JD, Shaffer SA, Gilmore R. Quantitative glycoproteomics reveals new classes of STT3A- and STT3B-dependent N-glycosylation sites. J Cell Biol 2019; 218:2782-2796. [PMID: 31296534 PMCID: PMC6683751 DOI: 10.1083/jcb.201904004] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 11/24/2022] Open
Abstract
Cherepanova et al. provide quantitative glycoproteomic analyses of human cells that lack either the STT3A or STT3B oligosaccharyltransferase (OST) complex, revealing new classes of STT3A- and STT3B-dependent glycosylation sites and indicating how cooperation between the OST complexes maximizes acceptor site occupancy in cellular glycoproteins. Human cells express two oligosaccharyltransferase complexes (STT3A and STT3B) with partially overlapping functions. The STT3A complex interacts directly with the protein translocation channel to mediate cotranslational glycosylation, while the STT3B complex can catalyze posttranslocational glycosylation. We used a quantitative glycoproteomics procedure to compare glycosylation of roughly 1,000 acceptor sites in wild type and mutant cells. Analysis of site occupancy data disclosed several new classes of STT3A-dependent acceptor sites including those with suboptimal flanking sequences and sites located within cysteine-rich protein domains. Acceptor sites located in short loops of multi-spanning membrane proteins represent a new class of STT3B-dependent site. Remarkably, the lumenal ER chaperone GRP94 was hyperglycosylated in STT3A-deficient cells, bearing glycans on five silent sites in addition to the normal glycosylation site. GRP94 was also hyperglycosylated in wild-type cells treated with ER stress inducers including thapsigargin, dithiothreitol, and NGI-1.
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Affiliation(s)
- Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
| | - Sergey V Venev
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA
| | - John D Leszyk
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA.,Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, MA
| | - Scott A Shaffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA.,Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, MA
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
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13
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Li X, Shi L, Dai X, Chen Y, Xie H, Feng M, Chen Y, Wang H. Expression plasticity and evolutionary changes extensively shape the sugar-mimic alkaloid adaptation of nondigestive glucosidase in lepidopteran mulberry-specialist insects. Mol Ecol 2018; 27:2858-2870. [PMID: 29752760 DOI: 10.1111/mec.14720] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/10/2018] [Accepted: 04/17/2018] [Indexed: 01/28/2023]
Abstract
During the co-evolutionary arms race between plants and herbivores, insects evolved systematic adaptive plasticity to minimize the chemical defence effects of their host plants. Previous studies mainly focused on the expressional plasticity of enzymes in detoxification and digestion. However, the expressional response and adaptive evolution of other fundamental regulators against host phytochemicals are largely unknown. Glucosidase II (GII), which is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit, is an evolutionarily conserved enzyme that regulates glycoprotein folding. In this study, we found that GIIα expression of the mulberry-specialist insect was significantly induced by mulberry leaf extract, 1-deoxynojirimycin (1-DNJ), whereas GIIβ transcripts were not significantly changed. Moreover, positive selection was detected in GIIα when the mulberry-specialist insects diverged from the lepidopteran order, whereas GIIβ was mainly subjected to purifying selection, thus indicating an asymmetrically selective pressure of GII subunits. In addition, positively selected sites were enriched in the GIIα of mulberry-specialist insects and located around the 1-DNJ-binding sites and in the C-terminal region, which could result in conformational changes that affect catalytic activity and substrate-binding efficiency. These results show that expression plasticity and evolutionary changes extensively shape sugar-mimic alkaloids adaptation of nondigestive glucosidase in lepidopteran mulberry-specialist insects. Our study provides novel insights into a deep understanding of the sequestration and adaptation of phytophagous specialists to host defensive compounds.
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Affiliation(s)
- Xiaotong Li
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Liangen Shi
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Xiangping Dai
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Yajie Chen
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Hongqing Xie
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Min Feng
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Yuyin Chen
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Huabing Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, China
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14
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Abstract
The endoplasmic reticulum (ER) is the site of maturation for roughly one-third of all cellular proteins. ER-resident molecular chaperones and folding catalysts promote folding and assembly in a diverse set of newly synthesized proteins. Because these processes are error-prone, all eukaryotic cells have a quality-control system in place that constantly monitors the proteins and decides their fate. Proteins with potentially harmful nonnative conformations are subjected to assisted folding or degraded. Persistent folding-defective proteins are distinguished from folding intermediates and targeted for degradation by a specific process involving clearance from the ER. Although the basic principles of these processes appear conserved from yeast to animals and plants, there are distinct differences in the ER-associated degradation of misfolded glycoproteins. The general importance of ER quality-control events is underscored by their involvement in the biogenesis of diverse cell surface receptors and their crucial maintenance of protein homeostasis under diverse stress conditions.
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Affiliation(s)
- Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria;
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15
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Interplay between P-Glycoprotein Expression and Resistance to Endoplasmic Reticulum Stressors. Molecules 2018; 23:molecules23020337. [PMID: 29415493 PMCID: PMC6017601 DOI: 10.3390/molecules23020337] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 12/13/2022] Open
Abstract
Multidrug resistance (MDR) is a phenotype of cancer cells with reduced sensitivity to a wide range of unrelated drugs. P-glycoprotein (P-gp)—a drug efflux pump (ABCB1 member of the ABC transporter gene family)—is frequently observed to be a molecular cause of MDR. The drug-efflux activity of P-gp is considered as the underlying mechanism of drug resistance against P-gp substrates and results in failure of cancer chemotherapy. Several pathological impulses such as shortages of oxygen and glucose supply, alterations of calcium storage mechanisms and/or processes of protein N-glycosylation in the endoplasmic reticulum (ER) leads to ER stress (ERS), characterized by elevation of unfolded protein cell content and activation of the unfolded protein response (UPR). UPR is responsible for modification of protein folding pathways, removal of misfolded proteins by ER associated protein degradation (ERAD) and inhibition of proteosynthesis. However, sustained ERS may result in UPR-mediated cell death. Neoplastic cells could escape from the death pathway induced by ERS by switching UPR into pro survival mechanisms instead of apoptosis. Here, we aimed to present state of the art information about consequences of P-gp expression on mechanisms associated with ERS development and regulation of the ERAD system, particularly focused on advances in ERS-associated therapy of drug resistant malignancies.
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16
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Satoh T, Kato K. Structural Aspects of ER Glycoprotein Quality-Control System Mediated by Glucose Tagging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1104:149-169. [PMID: 30484248 DOI: 10.1007/978-981-13-2158-0_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
N-linked oligosaccharides attached to proteins act as tags for glycoprotein quality control, ensuring their appropriate folding and trafficking in cells. Interactions with a variety of intracellular lectins determine glycoprotein fates. Monoglucosylated glycoforms are the hallmarks of incompletely folded glycoproteins in the protein quality-control system, in which glucosidase II and UDP-glucose/glycoprotein glucosyltransferase are, respectively, responsible for glucose trimming and attachment. In this review, we summarize a recently emerging view of the structural basis of the functional mechanisms of these key enzymes as well as substrate N-linked oligosaccharides exhibiting flexible structures, as revealed by applying a series of biophysical techniques including small-angle X-ray scattering, X-ray crystallography, high-speed atomic force microscopy , electron microscopy , and computational simulation in conjunction with NMR spectroscopy.
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Affiliation(s)
- Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan. .,Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, Japan.
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17
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Genetic code asymmetry supports diversity through experimentation with posttranslational modifications. Curr Opin Chem Biol 2017; 41:1-11. [PMID: 28923586 DOI: 10.1016/j.cbpa.2017.08.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/03/2017] [Accepted: 08/26/2017] [Indexed: 12/20/2022]
Abstract
Protein N-glycosylation has been identified in all three domains of life presumably conserved for its early role in glycoprotein folding. However, the N-glycans added to proteins in the secretory pathway of multicellular organisms are remodeling in the Golgi, increasing structural diversity exponentially and adding new layers of functionality in immunity, metabolism and other systems. The branching and elongation of N-glycan chains found on cell surface receptors generates a gradation of affinities for carbohydrate-binding proteins, the galectin, selectin and siglec families. These interactions adapt cellular responsiveness to environmental conditions, but their complexity presents a daunting challenge to drug design. To gain further insight, I review how N-glycans biosynthesis and biophysical properties provide a selective advantage in the form of tunable and ultrasensitive stimulus-response relationships. In addition, the N-glycosylation motif favors step-wise mutational experimentation with sites. Glycoproteins display accelerated evolution during vertebrate radiation, and the encoding asymmetry of NXS/T(X≠P) has left behind phylogenetic evidence suggesting that the genetic code may have been selected to optimize diversity in part through emerging posttranslational modifications.
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18
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The directed migration of gonadal distal tip cells in Caenorhabditis elegans requires NGAT-1, a ß1,4-N-acetylgalactosaminyltransferase enzyme. PLoS One 2017; 12:e0183049. [PMID: 28817611 PMCID: PMC5560668 DOI: 10.1371/journal.pone.0183049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/30/2017] [Indexed: 01/01/2023] Open
Abstract
Glycoproteins such as growth factor receptors and extracellular matrix have well-known functions in development and cancer progression, however, the glycans at sites of modification are often heterogeneous molecular populations which makes their functional characterization challenging. Here we provide evidence for a specific, discrete, well-defined glycan modification and regulation of a stage-specific cell migration in Caenorhabditis elegans. We show that a chain-terminating, putative null mutation in the gene encoding a predicted β1,4-N-acetylgalactosaminyltransferase, named ngat-1, causes a maternally rescued temperature sensitive (ts) defect in the second phase of the three phase migration pattern of the posterior, but not the anterior, hermaphrodite Distal Tip Cell (DTC). An amino-terminal partial deletion of ngat-1 causes a similar but lower penetrance ts phenotype. The existence of multiple ts alleles with distinctly different molecular DNA lesions, neither of which is likely to encode a ts protein, indicates that NGAT-1 normally prevents innate temperature sensitivity for phase 2 DTC pathfinding. Temperature shift analyses indicate that the ts period for the ngat-1 mutant defect ends by the beginning of post-embryonic development-nearly 3 full larval stages prior to the defective phase 2 migration affected by ngat-1 mutations. NGAT-1 homologs generate glycan-terminal GalNAc-β1-4GlcNAc, referred to as LacdiNAc modifications, on glycoproteins and glycolipids. We also found that the absence of the GnT1/Mgat1 activity [UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β-1,2-N-acetylglucosaminyltransferase 1 (encoded by C. elegans gly-12, gly-13, and gly-14 and homologous to vertebrate GnT1/Mgat1)], causes a similar spectrum of DTC phenotypes as ngat-1 mutations-primarily affecting posterior DTC phase 2 migration and preventing manifestation of the same innate ts period as ngat-1. GnT1/Mgat1 is a medial Golgi enzyme known to modify mannose residues and initiate N-glycan branching, an essential step in the biosynthesis of hybrid, paucimannose and complex-type N-glycans. Quadruple mutant animals bearing putative null mutations in ngat-1 and the three GnT genes (gly-12, gly-13, gly-14) were not enhanced for DTC migration defects, suggesting NGAT-1 and GnT1 act in the same pathway. These findings suggest that GnTI generates an N-glycan substrate for NGAT-1 modification, which is required at restrictive temperature (25°C) to prevent, stabilize, reverse or compensate a perinatal thermo-labile process (or structure) causing late larval stage DTC phase 2 migration errors.
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19
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Okuyama M, Miyamoto M, Matsuo I, Iwamoto S, Serizawa R, Tanuma M, Ma M, Klahan P, Kumagai Y, Tagami T, Kimura A. Substrate recognition of the catalytic α-subunit of glucosidase II from Schizosaccharomyces pombe. Biosci Biotechnol Biochem 2017; 81:1503-1511. [DOI: 10.1080/09168451.2017.1320520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Abstract
The recombinant catalytic α-subunit of N-glycan processing glucosidase II from Schizosaccharomyces pombe (SpGIIα) was produced in Escherichia coli. The recombinant SpGIIα exhibited quite low stability, with a reduction in activity to <40% after 2-days preservation at 4 °C, but the presence of 10% (v/v) glycerol prevented this loss of activity. SpGIIα, a member of the glycoside hydrolase family 31 (GH31), displayed the typical substrate specificity of GH31 α-glucosidases. The enzyme hydrolyzed not only α-(1→3)- but also α-(1→2)-, α-(1→4)-, and α-(1→6)-glucosidic linkages, and p-nitrophenyl α-glucoside. SpGIIα displayed most catalytic properties of glucosidase II. Hydrolytic activity of the terminal α-glucosidic residue of Glc2Man3-Dansyl was faster than that of Glc1Man3-Dansyl. This catalytic α-subunit also removed terminal glucose residues from native N-glycans (Glc2Man9GlcNAc2 and Glc1Man9GlcNAc2) although the activity was low.
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Affiliation(s)
- Masayuki Okuyama
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Masashi Miyamoto
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Ichiro Matsuo
- Graduate School of Science and Technology, Gunma University, Kiryu, Japan
| | - Shogo Iwamoto
- Graduate School of Science and Technology, Gunma University, Kiryu, Japan
| | - Ryo Serizawa
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Masanari Tanuma
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Min Ma
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Patcharapa Klahan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yuya Kumagai
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takayoshi Tagami
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Atsuo Kimura
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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20
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Xiao Y, Han J, Wang Q, Mao Y, Wei M, Jia W, Wei L. A Novel Interacting Protein SERP1 Regulates the N‐Linked Glycosylation and Function of GLP‐1 Receptor in the Liver. J Cell Biochem 2017; 118:3616-3626. [DOI: 10.1002/jcb.26207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 06/08/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Yuanyuan Xiao
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Junfeng Han
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Qianqian Wang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Yueqin Mao
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Meilin Wei
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Weiping Jia
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
| | - Li Wei
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes MellitusShanghai Key Clinical Center for Metabolic DiseaseShanghai 200233China
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21
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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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22
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Zhang K, Demarest SJ, Wu X, Fitchett JR. Glycosylation Profiling of α/β T Cell Receptor Constant Domains Expressed in Mammalian Cells. Methods Mol Biol 2017; 1575:197-213. [PMID: 28255882 DOI: 10.1007/978-1-4939-6857-2_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Glycoprofiling recombinant proteins expressed and secreted from mammalian cells is key to understanding their interactions with glycoprotein receptors in vivo. Recently, recombinant T cell receptors (TCRs) are being considered as therapeutic moieties. Here we present a mass spectrometry based protocol with a "bottom up" approach to characterize glycosylation in recombinant fusion proteins with α/β TCR constant domains expressed in mammalian cells. The protocol focuses on using peptide mass mapping and mass spectrometry for N-linked glycan profiling, including analyses of site occupancy, glycan heterogeneity, and possible glycan compositions and structures.
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MESH Headings
- Chromatography, Liquid
- Glycosylation
- HEK293 Cells
- Humans
- Mass Spectrometry
- Peptide Mapping/methods
- Protein Domains
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
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Affiliation(s)
- Kai Zhang
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA.
| | - Stephen J Demarest
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Xiufeng Wu
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Jonathan R Fitchett
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
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23
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Satoh T, Toshimori T, Noda M, Uchiyama S, Kato K. Interaction mode between catalytic and regulatory subunits in glucosidase II involved in ER glycoprotein quality control. Protein Sci 2016; 25:2095-2101. [PMID: 27576940 DOI: 10.1002/pro.3031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/28/2016] [Accepted: 08/29/2016] [Indexed: 12/18/2022]
Abstract
The glycoside hydrolase family 31 (GH31) α-glucosidases play vital roles in catabolic and regulated degradation, including the α-subunit of glucosidase II (GIIα), which catalyzes trimming of the terminal glucose residues of N-glycan in glycoprotein processing coupled with quality control in the endoplasmic reticulum (ER). Among the known GH31 enzymes, only GIIα functions with its binding partner, regulatory β-subunit (GIIβ), which harbors a lectin domain for substrate recognition. Although the structural data have been reported for GIIα and the GIIβ lectin domain, the interaction mode between GIIα and GIIβ remains unknown. Here, we determined the structure of a complex formed between GIIα and the GIIα-binding domain of GIIβ, thereby providing a structural basis underlying the functional extension of this unique GH31 enzyme.
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Affiliation(s)
- Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan. .,JST, PRESTO, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan.
| | - Takayasu Toshimori
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan.,Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.,Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Masanori Noda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Susumu Uchiyama
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.,Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan. .,Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan. .,Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.
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24
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Caputo AT, Alonzi DS, Marti L, Reca IB, Kiappes JL, Struwe WB, Cross A, Basu S, Lowe ED, Darlot B, Santino A, Roversi P, Zitzmann N. Structures of mammalian ER α-glucosidase II capture the binding modes of broad-spectrum iminosugar antivirals. Proc Natl Acad Sci U S A 2016; 113:E4630-8. [PMID: 27462106 PMCID: PMC4987793 DOI: 10.1073/pnas.1604463113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The biosynthesis of enveloped viruses depends heavily on the host cell endoplasmic reticulum (ER) glycoprotein quality control (QC) machinery. This dependency exceeds the dependency of host glycoproteins, offering a window for the targeting of ERQC for the development of broad-spectrum antivirals. We determined small-angle X-ray scattering (SAXS) and crystal structures of the main ERQC enzyme, ER α-glucosidase II (α-GluII; from mouse), alone and in complex with key ligands of its catalytic cycle and antiviral iminosugars, including two that are in clinical trials for the treatment of dengue fever. The SAXS data capture the enzyme's quaternary structure and suggest a conformational rearrangement is needed for the simultaneous binding of a monoglucosylated glycan to both subunits. The X-ray structures with key catalytic cycle intermediates highlight that an insertion between the +1 and +2 subsites contributes to the enzyme's activity and substrate specificity, and reveal that the presence of d-mannose at the +1 subsite renders the acid catalyst less efficient during the cleavage of the monoglucosylated substrate. The complexes with iminosugar antivirals suggest that inhibitors targeting a conserved ring of aromatic residues between the α-GluII +1 and +2 subsites would have increased potency and selectivity, thus providing a template for further rational drug design.
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Affiliation(s)
- Alessandro T Caputo
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Dominic S Alonzi
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Lucia Marti
- Institute of Sciences of Food Production, Consiglio Nazionale delle Ricerche Unit of Lecce, 73100 Lecce, Italy
| | - Ida-Barbara Reca
- Institute of Sciences of Food Production, Consiglio Nazionale delle Ricerche Unit of Lecce, 73100 Lecce, Italy
| | - J L Kiappes
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Weston B Struwe
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Alice Cross
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Souradeep Basu
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Edward D Lowe
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Benoit Darlot
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom; Ecole Nationale Supérieure de Chimie de Montpellier, 34296 Montpellier Cedex 5, France
| | - Angelo Santino
- Institute of Sciences of Food Production, Consiglio Nazionale delle Ricerche Unit of Lecce, 73100 Lecce, Italy
| | - Pietro Roversi
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
| | - Nicole Zitzmann
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
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25
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McClure ML, Barnes S, Brodsky JL, Sorscher EJ. Trafficking and function of the cystic fibrosis transmembrane conductance regulator: a complex network of posttranslational modifications. Am J Physiol Lung Cell Mol Physiol 2016; 311:L719-L733. [PMID: 27474090 DOI: 10.1152/ajplung.00431.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 07/26/2016] [Indexed: 12/19/2022] Open
Abstract
Posttranslational modifications add diversity to protein function. Throughout its life cycle, the cystic fibrosis transmembrane conductance regulator (CFTR) undergoes numerous covalent posttranslational modifications (PTMs), including glycosylation, ubiquitination, sumoylation, phosphorylation, and palmitoylation. These modifications regulate key steps during protein biogenesis, such as protein folding, trafficking, stability, function, and association with protein partners and therefore may serve as targets for therapeutic manipulation. More generally, an improved understanding of molecular mechanisms that underlie CFTR PTMs may suggest novel treatment strategies for CF and perhaps other protein conformational diseases. This review provides a comprehensive summary of co- and posttranslational CFTR modifications and their significance with regard to protein biogenesis.
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Affiliation(s)
- Michelle L McClure
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, Georgia
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26
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Porath B, Gainullin VG, Cornec-Le Gall E, Dillinger EK, Heyer CM, Hopp K, Edwards ME, Madsen CD, Mauritz SR, Banks CJ, Baheti S, Reddy B, Herrero JI, Bañales JM, Hogan MC, Tasic V, Watnick TJ, Chapman AB, Vigneau C, Lavainne F, Audrézet MP, Ferec C, Le Meur Y, Torres VE, Harris PC, Harris PC. Mutations in GANAB, Encoding the Glucosidase IIα Subunit, Cause Autosomal-Dominant Polycystic Kidney and Liver Disease. Am J Hum Genet 2016; 98:1193-1207. [PMID: 27259053 DOI: 10.1016/j.ajhg.2016.05.004] [Citation(s) in RCA: 280] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/03/2016] [Indexed: 02/06/2023] Open
Abstract
Autosomal-dominant polycystic kidney disease (ADPKD) is a common, progressive, adult-onset disease that is an important cause of end-stage renal disease (ESRD), which requires transplantation or dialysis. Mutations in PKD1 or PKD2 (∼85% and ∼15% of resolved cases, respectively) are the known causes of ADPKD. Extrarenal manifestations include an increased level of intracranial aneurysms and polycystic liver disease (PLD), which can be severe and associated with significant morbidity. Autosomal-dominant PLD (ADPLD) with no or very few renal cysts is a separate disorder caused by PRKCSH, SEC63, or LRP5 mutations. After screening, 7%-10% of ADPKD-affected and ∼50% of ADPLD-affected families were genetically unresolved (GUR), suggesting further genetic heterogeneity of both disorders. Whole-exome sequencing of six GUR ADPKD-affected families identified one with a missense mutation in GANAB, encoding glucosidase II subunit α (GIIα). Because PRKCSH encodes GIIβ, GANAB is a strong ADPKD and ADPLD candidate gene. Sanger screening of 321 additional GUR families identified eight further likely mutations (six truncating), and a total of 20 affected individuals were identified in seven ADPKD- and two ADPLD-affected families. The phenotype was mild PKD and variable, including severe, PLD. Analysis of GANAB-null cells showed an absolute requirement of GIIα for maturation and surface and ciliary localization of the ADPKD proteins (PC1 and PC2), and reduced mature PC1 was seen in GANAB(+/-) cells. PC1 surface localization in GANAB(-/-) cells was rescued by wild-type, but not mutant, GIIα. Overall, we show that GANAB mutations cause ADPKD and ADPLD and that the cystogenesis is most likely driven by defects in PC1 maturation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
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Cherepanova N, Shrimal S, Gilmore R. N-linked glycosylation and homeostasis of the endoplasmic reticulum. Curr Opin Cell Biol 2016; 41:57-65. [PMID: 27085638 DOI: 10.1016/j.ceb.2016.03.021] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 01/17/2023]
Abstract
As a major site of protein biosynthesis, homeostasis of the endoplasmic reticulum is critical for cell viability. Asparagine linked glycosylation of newly synthesized proteins by the oligosaccharyltransferase plays a central role in ER homeostasis due to the use of protein-linked oligosaccharides as recognition and timing markers for glycoprotein quality control pathways that discriminate between correctly folded proteins and terminally malfolded proteins destined for ER associated degradation. Recent findings indicate how the oligosaccharyltransferase achieves efficient and accurate glycosylation of the diverse proteins that enter the endoplasmic reticulum. In metazoan organisms two distinct OST complexes cooperate to maximize the glycosylation of nascent proteins. The STT3B complex glycosylates acceptor sites that have been skipped by the translocation channel associated STT3A complex.
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Affiliation(s)
- Natalia Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States.
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28
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Structural basis for two-step glucose trimming by glucosidase II involved in ER glycoprotein quality control. Sci Rep 2016; 6:20575. [PMID: 26847925 PMCID: PMC4742823 DOI: 10.1038/srep20575] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/06/2016] [Indexed: 01/10/2023] Open
Abstract
The endoplasmic reticulum (ER) has a sophisticated protein quality control system for the efficient folding of newly synthesized proteins. In this system, a variety of N-linked oligosaccharides displayed on proteins serve as signals recognized by series of intracellular lectins. Glucosidase II catalyzes two-step hydrolysis at α1,3-linked glucose–glucose and glucose–mannose residues of high-mannose-type glycans to generate a quality control protein tag that is transiently expressed on glycoproteins and recognized by ER chaperones. Here we determined the crystal structures of the catalytic α subunit of glucosidase II (GIIα) complexed with two different glucosyl ligands containing the scissile bonds of first- and second-step reactions. Our structural data revealed that the nonreducing terminal disaccharide moieties of the two kinds of substrates can be accommodated in a gourd-shaped bilocular pocket, thereby providing a structural basis for substrate-binding specificity in the two-step deglucosylation catalyzed by this enzyme.
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29
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Chiritoiu GN, Jandus C, Munteanu CV, Ghenea S, Gannon PO, Romero P, Petrescu SM. Epitope locatedN-glycans impair the MHC-I epitope generation and presentation. Electrophoresis 2016; 37:1448-60. [DOI: 10.1002/elps.201500449] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/15/2015] [Accepted: 12/15/2015] [Indexed: 11/07/2022]
Affiliation(s)
| | - Camilla Jandus
- Ludwig Cancer Research Center, Faculty of Biology and Medicine; University of Lausanne; Lausanne Switzerland
| | | | - Simona Ghenea
- Institute of Biochemistry; Romanian Academy; Bucharest Romania
| | - Philippe O. Gannon
- Department of Oncology, Lausanne University Hospital (CHUV); University of Lausanne; Lausanne Switzerland
| | - Pedro Romero
- Ludwig Cancer Research Center, Faculty of Biology and Medicine; University of Lausanne; Lausanne Switzerland
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Lamriben L, Graham JB, Adams BM, Hebert DN. N-Glycan-based ER Molecular Chaperone and Protein Quality Control System: The Calnexin Binding Cycle. Traffic 2016; 17:308-26. [PMID: 26676362 DOI: 10.1111/tra.12358] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 12/17/2022]
Abstract
Helenius and colleagues proposed over 20-years ago a paradigm-shifting model for how chaperone binding in the endoplasmic reticulum was mediated and controlled for a new type of molecular chaperone- the carbohydrate-binding chaperones, calnexin and calreticulin. While the originally established basics for this lectin chaperone binding cycle holds true today, there has been a number of important advances that have expanded our understanding of its mechanisms of action, role in protein homeostasis, and its connection to disease states that are highlighted in this review.
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Affiliation(s)
- Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jill B Graham
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Benjamin M Adams
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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Sakaue H, Iwashita S, Yamashita Y, Kida Y, Sakaguchi M. The N-terminal motif of PMP70 suppresses cotranslational targeting to the endoplasmic reticulum. J Biochem 2015; 159:539-51. [PMID: 26711236 DOI: 10.1093/jb/mvv132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/06/2015] [Indexed: 11/13/2022] Open
Abstract
Many membrane proteins possessing hydrophobic transmembrane (TM) segments are cotranslationally integrated into the endoplasmic reticulum (ER) membrane. Various peroxisomal and mitochondrial membrane proteins escape the ER-targeting mechanism and are targeted to their destinations. Here, we discovered a short segment in the 70-kDa peroxisomal membrane protein (PMP70) that suppresses ER targeting. The first TM segment has an intrinsic signal function that targets the nascent chain to the ER. The ER targeting was suppressed by a short N-terminal sequence of nine residues that is 80 residues upstream of the TM segment. Among the nine residues, Ser(5) is indispensable. The short segment also suppressed the signal peptide function of an authentic secretory protein. This function of the short segment was suppressed by the recombinant motif-GST fusion protein. The 50-kDa and 20-kDa proteins were crosslinked with the motif. The PMP70 molecule with the Ser5Ala point mutation predominantly localized to the ER. We propose the concept of an ER-targeting suppressor that suppresses the ER-targeting mechanism via a binding factor.
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Affiliation(s)
- Haruka Sakaue
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Shohei Iwashita
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Yukari Yamashita
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Yuichiro Kida
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Masao Sakaguchi
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
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32
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Dennis JW. Many Light Touches Convey the Message. Trends Biochem Sci 2015; 40:673-686. [DOI: 10.1016/j.tibs.2015.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/14/2015] [Accepted: 08/21/2015] [Indexed: 11/28/2022]
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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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Kobayashi M, Nagashio R, Jiang SX, Saito K, Tsuchiya B, Ryuge S, Katono K, Nakashima H, Fukuda E, Goshima N, Satoh Y, Masuda N, Saegusa M, Sato Y. Calnexin is a novel sero-diagnostic marker for lung cancer. Lung Cancer 2015; 90:342-5. [PMID: 26344721 DOI: 10.1016/j.lungcan.2015.08.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/11/2015] [Accepted: 08/19/2015] [Indexed: 11/27/2022]
Abstract
To develop sero-diagnostic markers for lung cancer, we generated monoclonal antibodies using lung adenocarcinoma (AC)-derived A549 cells as antigens by employing the random immunization method. Hybridoma supernatants were immunohistochemically screened for antibodies with AMeX-fixed and paraffin-embedded A549 cell preparations. Positive clones were monocloned twice through limiting dilutions. From the obtained monoclonal antibodies, one designated as KU-Lad-001 was recognized as calnexin (CANX) based on immunoprecipitation and MADLI TOF/TOF-MS analysis. To evaluate the utility of this antibody as a sero-diagnostic marker for lung cancer, we performed reverse-phase protein array analysis with samples of 195 lung cancer patients and 100 healthy controls. The CANX expression levels were significantly higher in lung cancer patients than in healthy controls (P<0.0001), and the area under the curve of ROC was 0.980, with 96.9% specificity and 99.0% sensitivity. Furthermore, since CANX was also detected in stage I disease, the serum CANX levels should be applicable markers discriminating lung cancer patients from healthy controls and possibly used in the detection of early lung cancer. To our knowledge, the present results provide evidence that CANX may be a novel sero-diagnostic marker for lung cancer.
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Affiliation(s)
- Makoto Kobayashi
- Department of Applied Tumor Pathology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan; Research Fellow of the Japan Society for the Promotion of Science, Japan
| | - Ryo Nagashio
- Department of Applied Tumor Pathology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan; Department of Molecular Diagnostics, School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Shi-Xu Jiang
- Department of Pathology, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Keita Saito
- Department of Applied Tumor Pathology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan
| | - Benio Tsuchiya
- Department of Applied Tumor Pathology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan
| | - Shinichiro Ryuge
- Department of Respiratory Medicine, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Ken Katono
- Department of Respiratory Medicine, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Hiroyasu Nakashima
- Department of Thoracic and Cardiovascular Surgery, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Eriko Fukuda
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Naoki Goshima
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Yukitoshi Satoh
- Department of Thoracic and Cardiovascular Surgery, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Noriyuki Masuda
- Department of Respiratory Medicine, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Makoto Saegusa
- Department of Pathology, School of Medicine, Kitasato University, Kanagawa, Japan
| | - Yuichi Sato
- Department of Applied Tumor Pathology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan; Department of Molecular Diagnostics, School of Allied Health Sciences, Kitasato University, Kanagawa, Japan.
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Abstract
The endoplasmic reticulum (ER) supports many cellular processes and performs diverse functions, including protein synthesis, translocation across the membrane, integration into the membrane, folding, and posttranslational modifications including N-linked glycosylation; and regulation of Ca2+ homeostasis. In mammalian systems, the majority of proteins synthesized by the rough ER have N-linked glycans critical for protein maturation. The N-linked glycan is used as a quality control signal in the secretory protein pathway. A series of chaperones, folding enzymes, glucosidases, and carbohydrate transferases support glycoprotein synthesis and processing. Perturbation of ER-associated functions such as disturbed ER glycoprotein quality control, protein glycosylation and protein folding results in activation of an ER stress coping response. Collectively this ER stress coping response is termed the unfolded protein response (UPR), and occurs through the activation of complex cytoplasmic and nuclear signaling pathways. Cellular and ER homeostasis depends on balanced activity of the ER protein folding, quality control, and degradation pathways; as well as management of the ER stress coping response.
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Abstract
Galectins are a family of widely expressed β-galactoside-binding lectins in metazoans. The 15 mammalian galectins have either one or two conserved carbohydrate recognition domains (CRDs), with galectin-3 being able to pentamerize; they form complexes that crosslink glycosylated ligands to form a dynamic lattice. The galectin lattice regulates the diffusion, compartmentalization and endocytosis of plasma membrane glycoproteins and glycolipids. The galectin lattice also regulates the selection, activation and arrest of T cells, receptor kinase signaling and the functionality of membrane receptors, including the glucagon receptor, glucose and amino acid transporters, cadherins and integrins. The affinity of transmembrane glycoproteins to the galectin lattice is proportional to the number and branching of their N-glycans; with branching being mediated by Golgi N-acetylglucosaminyltransferase-branching enzymes and the supply of UDP-GlcNAc through metabolite flux through the hexosamine biosynthesis pathway. The relative affinities of glycoproteins for the galectin lattice depend on the activities of the Golgi enzymes that generate the epitopes of their ligands and, thus, provide a means to analyze biological function of lectins and of the 'glycome' more broadly.
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Affiliation(s)
- Ivan R Nabi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, 2350 Health Sciences Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Jay Shankar
- Department of Cellular and Physiological Sciences, Life Sciences Institute, 2350 Health Sciences Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - James W Dennis
- Department of Medical Genetics and Laboratory Medicine and Pathology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
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Blanco-Herrera F, Moreno AA, Tapia R, Reyes F, Araya M, D'Alessio C, Parodi A, Orellana A. The UDP-glucose: glycoprotein glucosyltransferase (UGGT), a key enzyme in ER quality control, plays a significant role in plant growth as well as biotic and abiotic stress in Arabidopsis thaliana. BMC PLANT BIOLOGY 2015; 15:127. [PMID: 26017403 PMCID: PMC4465474 DOI: 10.1186/s12870-015-0525-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 05/18/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND UDP-glucose: glycoprotein glucosyltransferase (UGGT) is a key player in the quality control mechanism (ER-QC) that newly synthesized glycoproteins undergo in the ER. It has been shown that the UGGT Arabidopsis orthologue is involved in ER-QC; however, its role in plant physiology remains unclear. RESULTS Here, we show that two mutant alleles in the At1g71220 locus have none or reduced UGGT activity. In wild type plants, the AtUGGT transcript levels increased upon activation of the unfolded protein response (UPR). Interestingly, mutants in AtUGGT exhibited an endogenous up-regulation of genes that are UPR targets. In addition, mutants in AtUGGT showed a 30% reduction in the incorporation of UDP-Glucose into the ER suggesting that this enzyme drives the uptake of this substrate for the CNX/CRT cycle. Plants deficient in UGGT exhibited a delayed growth rate of the primary root and rosette as well as an alteration in the number of leaves. These mutants are more sensitive to pathogen attack as well as heat, salt, and UPR-inducing stressors. Additionally, the plants showed impairment in the establishment of systemic acquired resistance (SAR). CONCLUSIONS These results show that a lack of UGGT activity alters plant vegetative development and impairs the response to several abiotic and biotic stresses. Moreover, our results uncover an unexpected role of UGGT in the incorporation of UDP-Glucose into the ER lumen in Arabidopsis thaliana.
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Affiliation(s)
- Francisca Blanco-Herrera
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
| | - Adrián A Moreno
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
- FONDAP Center for Genome Regulation, Santiago, RM, Chile.
| | - Rodrigo Tapia
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
| | - Francisca Reyes
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
- FONDAP Center for Genome Regulation, Santiago, RM, Chile.
| | - Macarena Araya
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
| | - Cecilia D'Alessio
- Fundación Instituto Leloir and IIBBA, CONICET, Buenos Aires, Argentina.
- School of Sciences, University of Buenos Aires, Buenos Aires, Argentina.
| | - Armando Parodi
- Fundación Instituto Leloir and IIBBA, CONICET, Buenos Aires, Argentina.
| | - Ariel Orellana
- Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile.
- FONDAP Center for Genome Regulation, Santiago, RM, Chile.
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Tannous A, Pisoni GB, Hebert DN, Molinari M. N-linked sugar-regulated protein folding and quality control in the ER. Semin Cell Dev Biol 2015; 41:79-89. [PMID: 25534658 PMCID: PMC4474783 DOI: 10.1016/j.semcdb.2014.12.001] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/02/2014] [Indexed: 11/18/2022]
Abstract
Asparagine-linked glycans (N-glycans) are displayed on the majority of proteins synthesized in the endoplasmic reticulum (ER). Removal of the outermost glucose residue recruits the lectin chaperone malectin possibly involved in a first triage of defective polypeptides. Removal of a second glucose promotes engagement of folding and quality control machineries built around the ER lectin chaperones calnexin (CNX) and calreticulin (CRT) and including oxidoreductases and peptidyl-prolyl isomerases. Deprivation of the last glucose residue dictates the release of N-glycosylated polypeptides from the lectin chaperones. Correctly folded proteins are authorized to leave the ER. Non-native polypeptides are recognized by the ER quality control key player UDP-glucose glycoprotein glucosyltransferase 1 (UGT1), re-glucosylated and re-addressed to the CNX/CRT chaperone binding cycle to provide additional opportunity for the protein to fold in the ER. Failure to attain the native structure determines the selection of the misfolded polypeptides for proteasome-mediated degradation.
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Affiliation(s)
- Abla Tannous
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003, USA.
| | - Maurizio Molinari
- Università della Svizzera italiana, CH-6900 Lugano, Switzerland; Institute for Research in Biomedicine, Protein Folding and Quality Control, CH-6500 Bellinzona, Switzerland; Ecole Polytechnique Fédérale de Lausanne, School of Life Sciences, CH-1015 Lausanne, Switzerland.
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39
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Emerging structural insights into glycoprotein quality control coupled with N-glycan processing in the endoplasmic reticulum. Molecules 2015; 20:2475-91. [PMID: 25647580 PMCID: PMC6272264 DOI: 10.3390/molecules20022475] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/04/2015] [Accepted: 01/22/2015] [Indexed: 01/22/2023] Open
Abstract
In the endoplasmic reticulum (ER), the sugar chain is initially introduced onto newly synthesized proteins as a triantennary tetradecasaccharide (Glc3Man9GlcNAc2). The attached oligosaccharide chain is subjected to stepwise trimming by the actions of specific glucosidases and mannosidases. In these processes, the transiently expressed N-glycans, as processing intermediates, function as signals for the determination of glycoprotein fates, i.e., folding, transport, or degradation through interactions of a series of intracellular lectins. The monoglucosylated glycoforms are hallmarks of incompletely folded states of glycoproteins in this system, whereas the outer mannose trimming leads to ER-associated glycoprotein degradation. This review outlines the recently emerging evidence regarding the molecular and structural basis of this glycoprotein quality control system, which is regulated through dynamic interplay among intracellular lectins, glycosidases, and glycosyltransferase. Structural snapshots of carbohydrate-lectin interactions have been provided at the atomic level using X-ray crystallographic analyses. Conformational ensembles of uncomplexed triantennary high-mannose-type oligosaccharides have been characterized in a quantitative manner using molecular dynamics simulation in conjunction with nuclear magnetic resonance spectroscopy. These complementary views provide new insights into glycoprotein recognition in quality control coupled with N-glycan processing.
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Structural insight into substrate recognition by the endoplasmic reticulum folding-sensor enzyme: crystal structure of third thioredoxin-like domain of UDP-glucose:glycoprotein glucosyltransferase. Sci Rep 2014; 4:7322. [PMID: 25471383 PMCID: PMC4255179 DOI: 10.1038/srep07322] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/18/2014] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) possesses a protein quality control system that supports the efficient folding of newly synthesized glycoproteins. In this system, a series of N-linked glycan intermediates displayed on proteins serve as quality tags. The ER folding-sensor enzyme UDP-glucose:glycoprotein glucosyltransferase (UGGT) operates as the gatekeeper for ER quality control by specifically transferring monoglucose residues to incompletely folded glycoproteins, thereby allowing them to interact with lectin chaperone complexes to facilitate their folding. Despite its functional importance, no structural information is available for this key enzyme to date. To elucidate the folding-sensor mechanism in the ER, we performed a structural study of UGGT. Based on bioinformatics analyses, the folding-sensor region of UGGT was predicted to harbour three tandem thioredoxin (Trx)-like domains, which are often found in proteins involved in ER quality control. Furthermore, we determined the three-dimensional structure of the third Trx-like domain, which exhibits an extensive hydrophobic patch concealed by its flexible C-terminal helix. Our structural data suggest that this hydrophobic patch is involved in intermolecular interactions, thereby contributing to the folding-sensor mechanism of UGGT.
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Shrimal S, Cherepanova NA, Gilmore R. Cotranslational and posttranslocational N-glycosylation of proteins in the endoplasmic reticulum. Semin Cell Dev Biol 2014; 41:71-8. [PMID: 25460543 DOI: 10.1016/j.semcdb.2014.11.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 11/19/2022]
Abstract
Asparagine linked glycosylation of proteins is an essential protein modification reaction in most eukaryotic organisms. N-linked oligosaccharides are important for protein folding and stability, biosynthetic quality control, intracellular traffic and the physiological function of many N-glycosylated proteins. In metazoan organisms, the oligosaccharyltransferase is composed of a catalytic subunit (STT3A or STT3B) and a set of accessory subunits. Duplication of the catalytic subunit gene allowed cells to evolve OST complexes that act sequentially to maximize the glycosylation efficiency of the large number of proteins that are glycosylated in metazoan organisms. We will summarize recent progress in understanding the mechanism of (a) cotranslational glycosylation by the translocation channel associated STT3A complex, (b) the role of the STT3B complex in mediating cotranslational or posttranslocational glycosylation of acceptor sites that have been skipped by the STT3A complex, and (c) the role of the oxidoreductase MagT1 in STT3B-dependent glycosylation of cysteine-proximal acceptor sites.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States
| | - Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States.
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Fox RM, Andrew DJ. Transcriptional regulation of secretory capacity by bZip transcription factors. ACTA ACUST UNITED AC 2014; 10:28-51. [PMID: 25821458 PMCID: PMC4374484 DOI: 10.1007/s11515-014-1338-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cells of specialized secretory organs expand their secretory pathways to accommodate the increased protein load necessary for their function. The endoplasmic reticulum (ER), the Golgi apparatus and the secretory vesicles, expand not only the membrane components but also the protein machinery required for increased protein production and transport. Increased protein load causes an ER stress response akin to the Unfolded Protein Response (UPR). Recent work has implicated several bZip transcription factors in the regulation of protein components of the early secretory pathway necessary to alleviate this stress. Here, we highlight eight bZip transcription factors in regulating secretory pathway component genes. These include components of the three canonical branches of the UPR-ATF4, XBP1, and ATF6, as well as the five members of the Creb3 family of transcription factors.We review findings from both invertebrate and vertebrate model systems suggesting that all of these proteins increase secretory capacity in response to increased protein load. Finally, we propose that the Creb3 family of factors may have a dual role in secretory cell differentiation by also regulating the pathways necessary for cell cycle exit during terminal differentiation.
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Affiliation(s)
- Rebecca M Fox
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deborah J Andrew
- The Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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43
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Function and Structure Studies of GH Family 31 and 97 α-Glycosidases. Biosci Biotechnol Biochem 2014; 75:2269-77. [DOI: 10.1271/bbb.110610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Johswich A, Longuet C, Pawling J, Abdel Rahman A, Ryczko M, Drucker DJ, Dennis JW. N-glycan remodeling on glucagon receptor is an effector of nutrient sensing by the hexosamine biosynthesis pathway. J Biol Chem 2014; 289:15927-41. [PMID: 24742675 DOI: 10.1074/jbc.m114.563734] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glucose homeostasis in mammals is dependent on the opposing actions of insulin and glucagon. The Golgi N-acetylglucosaminyltransferases encoded by Mgat1, Mgat2, Mgat4a/b/c, and Mgat5 modify the N-glycans on receptors and solute transporter, possibly adapting activities in response to the metabolic environment. Herein we report that Mgat5(-/-) mice display diminished glycemic response to exogenous glucagon, together with increased insulin sensitivity. Glucagon receptor signaling and gluconeogenesis in Mgat5(-/-) cultured hepatocytes was impaired. In HEK293 cells, signaling by ectopically expressed glucagon receptor was increased by Mgat5 expression and GlcNAc supplementation to UDP-GlcNAc, the donor substrate shared by Mgat branching enzymes. The mobility of glucagon receptor in primary hepatocytes was reduced by galectin-9 binding, and the strength of the interaction was dependent on Mgat5 and UDP-GlcNAc levels. Finally, oral GlcNAc supplementation rescued the glucagon response in Mgat5(-/-) hepatocytes and mice, as well as glycolytic metabolites and UDP-GlcNAc levels in liver. Our results reveal that the hexosamine biosynthesis pathway and GlcNAc salvage contribute to glucose homeostasis through N-glycan branching on glucagon receptor.
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Affiliation(s)
- Anita Johswich
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and
| | - Christine Longuet
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and
| | - Judy Pawling
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and
| | - Anas Abdel Rahman
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and
| | - Michael Ryczko
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and the Departments of Molecular Genetics
| | - Daniel J Drucker
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and Medicine, University of Toronto, Toronto, Ontario M5R 0A3, Canada
| | - James W Dennis
- From the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada and the Departments of Molecular Genetics, Laboratory Medicine and Pathology, and Medicine, University of Toronto, Toronto, Ontario M5R 0A3, Canada
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Williams R, Ma X, Schott RK, Mohammad N, Ho CY, Li CF, Chang BSW, Demetriou M, Dennis JW. Encoding asymmetry of the N-glycosylation motif facilitates glycoprotein evolution. PLoS One 2014; 9:e86088. [PMID: 24475074 PMCID: PMC3901687 DOI: 10.1371/journal.pone.0086088] [Citation(s) in RCA: 15] [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: 09/12/2013] [Accepted: 12/10/2013] [Indexed: 12/02/2022] Open
Abstract
Protein N-glycosylation is found in all domains of life and has a conserved role in glycoprotein folding and stability. In animals, glycoproteins transit through the Golgi where the N-glycans are trimmed and rebuilt with sequences that bind lectins, an innovation that greatly increases structural diversity and redundancy of glycoprotein-lectin interaction at the cell surface. Here we ask whether the natural tension between increasing diversity (glycan-protein interactions) and site multiplicity (backup and status quo) might be revealed by a phylogenic examination of glycoproteins and NXS/T(X≠P) N-glycosylation sites. Site loss is more likely by mutation at Asn encoded by two adenosine (A)-rich codons, while site gain is more probable by generating Ser or Thr downstream of an existing Asn. Thus mutations produce sites at novel positions more frequently than the reversal of recently lost sites, and therefore more paths though sequence space are made available to natural selection. An intra-species comparison of secretory and cytosolic proteins revealed a departure from equilibrium in sequences one-mutation-away from NXS/T and in (A) content, indicating strong selective pressures and exploration of N-glycosylation positions during vertebrate evolution. Furthermore, secretory proteins have evolved at rates proportional to N-glycosylation site number, indicating adaptive interactions between the N-glycans and underlying protein. Given the topology of the genetic code, mutation of (A) is more often nonsynonomous, and Lys, another target of many PTMs, is also encoded by two (A)-rich codons. An examination of acetyl-Lys sites in proteins indicated similar evolutionary dynamics, consistent with asymmetry of the target and recognition portions of modified sites. Our results suggest that encoding asymmetry is an ancient mechanism of evolvability that increases diversity and experimentation with PTM site positions. Strong selective pressures on PTMs may have contributed to the A+T→G+C shift in genome-wide nucleotide composition during metazoan radiation.
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Affiliation(s)
- Ryan Williams
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Xiangyuan Ma
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathology, University of Toronto, Toronto, Ontario, Canada
| | - Ryan K. Schott
- Department of Ecology & Evolutionary, Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Naveed Mohammad
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Chi Yip Ho
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Carey F. Li
- Department of Neurology, University of California, Irvine, California, United States of America
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, United States of America
| | - Belinda S. W. Chang
- Department of Ecology & Evolutionary, Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Michael Demetriou
- Department of Neurology, University of California, Irvine, California, United States of America
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, United States of America
| | - James W. Dennis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Bieberich E. Synthesis, Processing, and Function of N-glycans in N-glycoproteins. ADVANCES IN NEUROBIOLOGY 2014; 9:47-70. [PMID: 25151374 DOI: 10.1007/978-1-4939-1154-7_3] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Many membrane-resident and secrected proteins, including growth factors and their receptors, are N-glycosylated. The initial N-glycan structure is synthesized in the endoplasmic reticulum (ER) as a branched structure on a lipid anchor (dolichol pyrophosphate) and then co-translationally, "en bloc" transferred and linked via N-acetylglucosamine to asparagine within a specific N-glycosylation acceptor sequence of the nascent recipient protein. In the ER and then the Golgi apparatus, the N-linked glycan structure is modified by hydrolytic removal of sugar residues ("trimming") followed by re-glycosylation with additional sugar residues ("processing") such as galactose, fucose, or sialic acid to form complex N-glycoproteins. While the sequence of the reactions leading to biosynthesis, "en bloc" transfer and processing of N-glycans is well investigated, it is still not completely understood how N-glycans affect the biological fate and function of N-glycoproteins. This review discusses the biology of N-glycoprotein synthesis, processing, and function with specific reference to the physiology and pathophysiology of the nervous system.
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Affiliation(s)
- Erhard Bieberich
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, 1120 15th Street Room CA4012, Augusta, GA, 30912, USA,
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47
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Drozdova T, Papillon J, Cybulsky AV. Nephrin missense mutations: induction of endoplasmic reticulum stress and cell surface rescue by reduction in chaperone interactions. Physiol Rep 2013; 1:e00086. [PMID: 24303155 PMCID: PMC3831901 DOI: 10.1002/phy2.86] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 12/12/2022] Open
Abstract
Nephrin, an important component of the podocyte filtration slit diaphragm, plays a key role in the maintenance of glomerular permselectivity. Mutations in nephrin lead to proteinuria and congenital nephrotic syndrome. Nephrin undergoes posttranslational modifications in the endoplasmic reticulum (ER) prior to export to the plasma membrane. We examined the effects of human nephrin disease-associated missense mutations on nephrin folding in the ER and on cellular trafficking in cultured cells. Compared with wild-type (WT) nephrin, the mutants showed impaired glycosylation and enhanced association with the ER chaperone, calnexin, as well as accumulation in the ER. Nephrin mutants demonstrated enhanced ubiquitination, and they underwent ER-associated degradation. Certain nephrin mutants did not traffic to the plasma membrane. Expression of nephrin mutants resulted in the stimulation of the activating transcription factor-6 pathway of the unfolded protein response, and an increase in the ER chaperone, Grp94. We treated cells with castanospermine (an inhibitor of glucosidase I) in order to decrease the association of nephrin mutants with calnexin. Castanospermine increased plasma membrane expression of nephrin mutants; however, full glycosylation and signaling activity of the mutants were not restored. Modulation of ER quality control mechanisms represents a potential new approach to development of therapies for proteinuric kidney disease, including congenital nephrotic syndrome.
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Affiliation(s)
- Tetyana Drozdova
- Department of Medicine, McGill University Health Centre, McGill University Montreal, Quebec, Canada
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48
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Arribas-González E, Alonso-Torres P, Aragón C, López-Corcuera B. Calnexin-assisted biogenesis of the neuronal glycine transporter 2 (GlyT2). PLoS One 2013; 8:e63230. [PMID: 23650557 PMCID: PMC3641136 DOI: 10.1371/journal.pone.0063230] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/30/2013] [Indexed: 11/20/2022] Open
Abstract
The neuronal transporter GlyT2 is a polytopic, 12-transmembrane domain, plasma membrane glycoprotein involved in the removal and recycling of synaptic glycine from inhibitory synapses. Mutations in the human GlyT2 gene (SLC6A5) that cause deficient glycine transport or defective GlyT2 trafficking are the second most common cause of hyperekplexia or startle disease. In this study we examined several aspects of GlyT2 biogenesis that involve the endoplasmic reticulum chaperone calnexin (CNX). CNX binds transiently to an intermediate under-glycosylated transporter precursor and facilitates GlyT2 processing. In cells expressing GlyT2, transporter accumulation and transport activity were attenuated by siRNA-mediated CNX knockdown and enhanced by CNX overexpression. GlyT2 binding to CNX was mediated by glycan and polypeptide-based interactions as revealed by pharmacological approaches and the behavior of GlyT2 N-glycan-deficient mutants. Moreover, transporter folding appeared to be stabilized by N-glycans. Co-expression of CNX and a fully non-glycosylated mutant rescues glycine transport but not mutant surface expression. Hence, CNX discriminates between different conformational states of GlyT2 displaying a lectin-independent chaperone activity. GlyT2 wild-type and mutant transporters were finally degraded in the lysosome. Our findings provide further insight into GlyT2 biogenesis, and a useful framework for the study of newly synthesized GlyT2 transporters bearing hyperekplexia mutations.
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Affiliation(s)
- Esther Arribas-González
- Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
- IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pablo Alonso-Torres
- Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Aragón
- Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain
- IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Beatriz López-Corcuera
- Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid, Spain
- IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
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Watanabe S, Kakudo A, Ohta M, Mita K, Fujiyama K, Inumaru S. Molecular cloning and characterization of the α-glucosidase II from Bombyx mori and Spodoptera frugiperda. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:319-327. [PMID: 23376632 DOI: 10.1016/j.ibmb.2013.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/12/2013] [Accepted: 01/16/2013] [Indexed: 06/01/2023]
Abstract
The α-glucosidase II (GII) is a heterodimer of α- and β-subunits and important for N-glycosylation processing and quality control of nascent glycoproteins. Although high concentration of α-glucosidase inhibitors from mulberry leaves accumulate in silkworms (Bombyx mori) by feeding, silkworm does not show any toxic symptom against these inhibitors and N-glycosylation of recombinant proteins is not affected. We, therefore, hypothesized that silkworm GII is not sensitive to the α-glucosidase inhibitors from mulberry leaves. However, the genes for B. mori GII subunits have not yet been identified, and the protein has not been characterized. Therefore, we isolated the B. mori GII α- and β-subunit genes and the GII α-subunit gene of Spodoptera frugiperda, which does not feed on mulberry leaves. We used a baculovirus expression system to produce the recombinant GII subunits and identified their enzyme characteristics. The recombinant GII α-subunits of B. mori and S. frugiperda hydrolyzed p-nitrophenyl α-d-glucopyranoside (pNP-αGlc) but were inactive toward N-glycan. Although the B. mori GII β-subunit was not required for the hydrolysis of pNP-αGlc, a B. mori GII complex of the α- and β-subunits was required for N-glycan cleavage. As hypothesized, the B. mori GII α-subunit protein was less sensitive to α-glucosidase inhibitors than was the S. frugiperda GII α-subunit protein. Our observations suggest that the low sensitivity of GII contributes to the ability of B. mori to evade the toxic effect of α-glucosidase inhibitors from mulberry leaves.
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Affiliation(s)
- Satoko Watanabe
- Life Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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50
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Shrimal S, Trueman SF, Gilmore R. Extreme C-terminal sites are posttranslocationally glycosylated by the STT3B isoform of the OST. ACTA ACUST UNITED AC 2013; 201:81-95. [PMID: 23530066 PMCID: PMC3613688 DOI: 10.1083/jcb.201301031] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glycosylation in the C-terminal 50–55 residues of proteins is mediated posttranslocationally by the STT3B isoform of oligosaccharyltransferase, with a preference for NXT sites. Metazoan organisms assemble two isoforms of the oligosaccharyltransferase (OST) that have different catalytic subunits (STT3A or STT3B) and partially nonoverlapping roles in asparagine-linked glycosylation. The STT3A isoform of the OST is primarily responsible for co-translational glycosylation of the nascent polypeptide as it enters the lumen of the endoplasmic reticulum. The C-terminal 65–75 residues of a glycoprotein will not contact the translocation channel–associated STT3A isoform of the OST complex before chain termination. Biosynthetic pulse labeling of five human glycoproteins showed that extreme C-terminal glycosylation sites were modified by an STT3B-dependent posttranslocational mechanism. The boundary for STT3B-dependent glycosylation of C-terminal sites was determined to fall between 50 and 55 residues from the C terminus of a protein. C-terminal NXT sites were glycosylated more rapidly and efficiently than C-terminal NXS sites. Bioinformatics analysis of glycopeptide databases from metazoan organisms revealed a lower density of C-terminal acceptor sites in glycoproteins because of reduced positive selection of NXT sites and negative selection of NXS sites.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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