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Hendershot LM, Buck TM, Brodsky JL. The Essential Functions of Molecular Chaperones and Folding Enzymes in Maintaining Endoplasmic Reticulum Homeostasis. J Mol Biol 2024; 436:168418. [PMID: 38143019 DOI: 10.1016/j.jmb.2023.168418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
It has been estimated that up to one-third of the proteins encoded by the human genome enter the endoplasmic reticulum (ER) as extended polypeptide chains where they undergo covalent modifications, fold into their native structures, and assemble into oligomeric protein complexes. The fidelity of these processes is critical to support organellar, cellular, and organismal health, and is perhaps best underscored by the growing number of disease-causing mutations that reduce the fidelity of protein biogenesis in the ER. To meet demands encountered by the diverse protein clientele that mature in the ER, this organelle is populated with a cadre of molecular chaperones that prevent protein aggregation, facilitate protein disulfide isomerization, and lower the activation energy barrier of cis-trans prolyl isomerization. Components of the lectin (glycan-binding) chaperone system also reside within the ER and play numerous roles during protein biogenesis. In addition, the ER houses multiple homologs of select chaperones that can recognize and act upon diverse peptide signatures. Moreover, redundancy helps ensure that folding-compromised substrates are unable to overwhelm essential ER-resident chaperones and enzymes. In contrast, the ER in higher eukaryotic cells possesses a single member of the Hsp70, Hsp90, and Hsp110 chaperone families, even though several homologs of these molecules reside in the cytoplasm. In this review, we discuss specific functions of the many factors that maintain ER quality control, highlight some of their interactions, and describe the vulnerabilities that arise from the absence of multiple members of some chaperone families.
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Affiliation(s)
- Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States.
| | - Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
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Zhao P, Wang C, Sun S, Wang X, Balch WE. Tracing genetic diversity captures the molecular basis of misfolding disease. Nat Commun 2024; 15:3333. [PMID: 38637533 PMCID: PMC11026414 DOI: 10.1038/s41467-024-47520-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Genetic variation in human populations can result in the misfolding and aggregation of proteins, giving rise to systemic and neurodegenerative diseases that require management by proteostasis. Here, we define the role of GRP94, the endoplasmic reticulum Hsp90 chaperone paralog, in managing alpha-1-antitrypsin deficiency on a residue-by-residue basis using Gaussian process regression-based machine learning to profile the spatial covariance relationships that dictate protein folding arising from sequence variants in the population. Covariance analysis suggests a role for the ATPase activity of GRP94 in controlling the N- to C-terminal cooperative folding of alpha-1-antitrypsin responsible for the correction of liver aggregation and lung-disease phenotypes of alpha-1-antitrypsin deficiency. Gaussian process-based spatial covariance profiling provides a standard model built on covariant principles to evaluate the role of proteostasis components in guiding information flow from genome to proteome in response to genetic variation, potentially allowing us to intervene in the onset and progression of complex multi-system human diseases.
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Affiliation(s)
- Pei Zhao
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China.
| | - Shuhong Sun
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Department of Nutrition and Food Hygiene, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Institute for Brain Tumors, Collaborative Innovation Center for Cancer Personalized Medicine, and Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Xi Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
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Fung C, Wilding B, Schittenhelm RB, Bryson-Richardson RJ, Bird PI. Expression of the Z Variant of α1-Antitrypsin Suppresses Hepatic Cholesterol Biosynthesis in Transgenic Zebrafish. Int J Mol Sci 2023; 24:ijms24032475. [PMID: 36768797 PMCID: PMC9917206 DOI: 10.3390/ijms24032475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/31/2023] Open
Abstract
Individuals homozygous for the Pi*Z allele of SERPINA1 (ZAAT) are susceptible to lung disease due to insufficient α1-antitrypsin secretion into the circulation and may develop liver disease due to compromised protein folding that leads to inclusion body formation in the endoplasmic reticulum (ER) of hepatocytes. Transgenic zebrafish expressing human ZAAT show no signs of hepatic accumulation despite displaying serum insufficiency, suggesting the defect in ZAAT secretion occurs independently of its tendency to form inclusion bodies. In this study, proteomic, transcriptomic, and biochemical analysis provided evidence of suppressed Srebp2-mediated cholesterol biosynthesis in the liver of ZAAT-expressing zebrafish. To investigate the basis for this perturbation, CRISPR/Cas9 gene editing was used to manipulate ER protein quality control factors. Mutation of erlec1 resulted in a further suppression in the cholesterol biosynthesis pathway, confirming a role for this ER lectin in targeting misfolded ZAAT for ER-associated degradation (ERAD). Mutation of the two ER mannosidase homologs enhanced ZAAT secretion without inducing hepatic accumulation. These insights into hepatic ZAAT processing suggest potential therapeutic targets to improve secretion and alleviate serum insufficiency in this form of the α1-antitrypsin disease.
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Affiliation(s)
- Connie Fung
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Correspondence: (C.F.); (P.I.B.)
| | - Brendan Wilding
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
| | - Ralf B. Schittenhelm
- Monash Proteomics and Metabolomics Facility, Monash University, Melbourne 3800, Australia
| | | | - Phillip I. Bird
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Correspondence: (C.F.); (P.I.B.)
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Emerging roles of endoplasmic reticulum proteostasis in brain development. Cells Dev 2022; 170:203781. [DOI: 10.1016/j.cdev.2022.203781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/12/2022] [Accepted: 04/20/2022] [Indexed: 11/21/2022]
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Trafficking-defective mutant PROKR2 cycles between endoplasmic reticulum and Golgi to attenuate endoplasmic reticulum stress. Proc Natl Acad Sci U S A 2022; 119:2102248119. [PMID: 35173048 PMCID: PMC8872787 DOI: 10.1073/pnas.2102248119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2021] [Indexed: 11/18/2022] Open
Abstract
The endoplasmic reticulum (ER) possesses a quality control system that prevents misfolded proteins from leaving the ER for routing to the ER-associated degradation pathway. Some misfolded proteins can escape the ER to reach the Golgi, where they are then retrieved from the Golgi back to the ER for degradation, but why this occurs needs to be clarified. Studying a mutant prokineticin receptor 2 identified in patients with hypogonadotropic hypogonadism as a model, we find that the post-ER retrieval system provides another layer of quality control and also lowers the load of misfolded proteins in the ER to reduce ER stress. Our findings reveal the importance of a post-ER quality control mechanism in contributing to cellular homeostasis. G protein–coupled receptors (GPCRs) play crucial roles in numerous physiological and pathological processes. Mutations in GPCRs that result in loss of function or alterations in signaling can lead to inherited or acquired diseases. Herein, studying prokineticin receptor 2 (PROKR2), we initially identify distinct interactomes for wild-type (WT) versus a mutant (P290S) PROKR2 that causes hypogonadotropic hypogonadism. We then find that both the WT and mutant PROKR2 are targeted for endoplasmic reticulum (ER)-associated degradation, but the mutant is degraded to a greater extent. Further analysis revealed that both forms can also leave the ER to reach the Golgi. However, whereas most of the WT is further transported to the cell surface, most of the mutant is retrieved to the ER. Thus, the post-ER itinerary plays an important role in distinguishing the ultimate fate of the WT versus the mutant. We have further discovered that this post-ER itinerary reduces ER stress induced by the mutant PROKR2. Moreover, we extend the core findings to another model GPCR. Our findings advance the understanding of disease pathogenesis induced by a mutation at a key residue that is conserved across many GPCRs and thus contributes to a fundamental understanding of the diverse mechanisms used by cellular quality control to accommodate misfolded proteins.
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Zhang N, Zabotina OA. Critical Determinants in ER-Golgi Trafficking of Enzymes Involved in Glycosylation. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030428. [PMID: 35161411 PMCID: PMC8840164 DOI: 10.3390/plants11030428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 05/03/2023]
Abstract
All living cells generate structurally complex and compositionally diverse spectra of glycans and glycoconjugates, critical for organismal evolution, development, functioning, defense, and survival. Glycosyltransferases (GTs) catalyze the glycosylation reaction between activated sugar and acceptor substrate to synthesize a wide variety of glycans. GTs are distributed among more than 130 gene families and are involved in metabolic processes, signal pathways, cell wall polysaccharide biosynthesis, cell development, and growth. Glycosylation mainly takes place in the endoplasmic reticulum (ER) and Golgi, where GTs and glycosidases involved in this process are distributed to different locations of these compartments and sequentially add or cleave various sugars to synthesize the final products of glycosylation. Therefore, delivery of these enzymes to the proper locations, the glycosylation sites, in the cell is essential and involves numerous secretory pathway components. This review presents the current state of knowledge about the mechanisms of protein trafficking between ER and Golgi. It describes what is known about the primary components of protein sorting machinery and trafficking, which are recognition sites on the proteins that are important for their interaction with the critical components of this machinery.
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Demaretz S, Seaayfan E, Bakhos-Douaihy D, Frachon N, Kömhoff M, Laghmani K. Golgi Alpha1,2-Mannosidase IA Promotes Efficient Endoplasmic Reticulum-Associated Degradation of NKCC2. Cells 2021; 11:cells11010101. [PMID: 35011665 PMCID: PMC8750359 DOI: 10.3390/cells11010101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 12/18/2022] Open
Abstract
Mutations in the apically located kidney Na-K-2Cl cotransporter NKCC2 cause type I Bartter syndrome, a life-threatening kidney disorder. We previously showed that transport from the ER represents the limiting phase in NKCC2 journey to the cell surface. Yet very little is known about the ER quality control components specific to NKCC2 and its disease-causing mutants. Here, we report the identification of Golgi alpha1, 2-mannosidase IA (ManIA) as a novel binding partner of the immature form of NKCC2. ManIA interaction with NKCC2 takes place mainly at the cis-Golgi network. ManIA coexpression decreased total NKCC2 protein abundance whereas ManIA knock-down produced the opposite effect. Importantly, ManIA coexpression had a more profound effect on NKCC2 folding mutants. Cycloheximide chase assay showed that in cells overexpressing ManIA, NKCC2 stability and maturation are heavily hampered. Deleting the cytoplasmic region of ManIA attenuated its interaction with NKCC2 and inhibited its effect on the maturation of the cotransporter. ManIA-induced reductions in NKCC2 expression were offset by the proteasome inhibitor MG132. Likewise, kifunensine treatment greatly reduced ManIA effect, strongly suggesting that mannose trimming is involved in the enhanced ERAD of the cotransporter. Moreover, depriving ManIA of its catalytic domain fully abolished its effect on NKCC2. In summary, our data demonstrate the presence of a ManIA-mediated ERAD pathway in renal cells promoting retention and degradation of misfolded NKCC2 proteins. They suggest a model whereby Golgi ManIA contributes to ERAD of NKCC2, by promoting the retention, recycling, and ERAD of misfolded proteins that initially escape protein quality control surveillance within the ER.
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Affiliation(s)
- Sylvie Demaretz
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Elie Seaayfan
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Dalal Bakhos-Douaihy
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Nadia Frachon
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Martin Kömhoff
- Division of Pediatric Nephrology and Transplantation, University Children’s Hospital, Philipps-University, 35043 Marburg, Germany;
| | - Kamel Laghmani
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
- Correspondence:
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Corma-Gómez A, Macías J, Rivero A, Rivero-Juarez A, de los Santos I, Reus-Bañuls S, Morano L, Merino D, Palacios R, Galera C, Fernández-Fuertes M, González-Serna A, de Rojas I, Ruiz A, Sáez ME, Real LM, Pineda JA. A Genome-Wide Association Study on Liver Stiffness Changes during Hepatitis C Virus Infection Cure. Diagnostics (Basel) 2021; 11:1501. [PMID: 34441435 PMCID: PMC8394459 DOI: 10.3390/diagnostics11081501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 02/07/2023] Open
Abstract
Liver stiffness (LS) at sustained virological response (SVR) after direct-acting antivirals (DAA)-based therapy is a predictor of liver events in hepatitis C virus (HCV)-infected patients. The study aim was to identify genetic factors associated with LS changes from the moment of starting anti-HCV therapy to SVR. This prospective study included HCV-infected patients from the GEHEP-011 cohort who achieved SVR with DAA-based therapy, with LS pre-treatment ≥ 9.5 kPa and LS measurement available at SVR. Plink and Magma software were used to carry out genome-wide single-nucleotide polymorphism (SNP)-based and gene-based association analyses, respectively. The ShinyGO application was used for exploring enrichment in Gene Ontology (GO) categories for biological processes. Overall, 242 patients were included. Median (quartile 1, quartile 3) LS values at pre-treatment and at SVR were 16.8 (12, 28) kPa and 12.0 (8.5, 19.3) kPa, respectively. Thirty-five SNPs and three genes reached suggestive association with LS changes from the moment of starting anti-HCV therapy to SVR. GO categories related to DNA packaging complex, DNA conformation change, chromosome organization and chromatin organization were significantly enriched. Our study reports possible genetic factors associated with LS changes during HCV-infection cure. In addition, our results suggest that processes related to DNA conformation are also involved in these changes.
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Affiliation(s)
- Anaïs Corma-Gómez
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
| | - Juan Macías
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
- Departamento de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
| | - Antonio Rivero
- Unidad de Enfermedades Infecciosas, Hospital Universitario Reina Sofía, Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (A.R.); (A.R.-J.)
| | - Antonio Rivero-Juarez
- Unidad de Enfermedades Infecciosas, Hospital Universitario Reina Sofía, Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (A.R.); (A.R.-J.)
| | - Ignacio de los Santos
- Unidad de Medicina Interna y Enfermedades Infecciosas, Hospital de La Princesa, 28006 Madrid, Spain;
| | - Sergio Reus-Bañuls
- Unidad de Enfermedades Infecciosas, Hospital General Universitario de Alicante, 03010 Alicante, Spain;
| | - Luis Morano
- Unidad de Patología Infecciosa, Hospital Universitario Alvaro Cunqueiro, Instituto de Investigación Sanitaria Galicia Sur (IISGS), 36312 Vigo, Spain;
| | - Dolores Merino
- Unidad de Enfermedades Infecciosas, Hospital Universitario Juan Ramón Jiménez, 21005 Huelva, Spain;
| | - Rosario Palacios
- Unidad de Enfermedades Infecciosas y Microbiología, Hospital Virgen de la Victoria, 29010 Málaga, Spain;
| | - Carlos Galera
- Unidad de Medicina Interna, Hospital Clínico Universitario Virgen de la Arrixaca, 30120 Murcia, Spain;
| | - Marta Fernández-Fuertes
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
| | - Alejandro González-Serna
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
| | - Itziar de Rojas
- Fundació ACE—Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya (UIC), 08028 Barcelona, Spain; (I.d.R.); (A.R.)
- CIBERNED Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Agustín Ruiz
- Fundació ACE—Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya (UIC), 08028 Barcelona, Spain; (I.d.R.); (A.R.)
- CIBERNED Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - María E. Sáez
- Centro Andaluz de Estudios Bioinformáticos (CAEBI, SL), 41013 Sevilla, Spain;
| | - Luis M. Real
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
- Departamento de Especialidades Quirúrgicas, Bioquímica e Inmunología, Universidad de Málaga, 29010 Málaga, Spain
| | - Juan A. Pineda
- Unidad Clínica de Enfermedades Infecciosas y Microbiología, Hospital de Valme, 41014 Sevilla, Spain; (A.C.-G.); (J.M.); (M.F.-F.); (A.G.-S.); (J.A.P.)
- Departamento de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
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Kemme L, Grüneberg M, Reunert J, Rust S, Park J, Westermann C, Wada Y, Schwartz O, Marquardt T. Translational balancing questioned: Unaltered glycosylation during disulfiram treatment in mannosyl-oligosaccharide alpha-1,2-mannnosidase-congenital disorders of glycosylation (MAN1B1-CDG). JIMD Rep 2021; 60:42-55. [PMID: 34258140 PMCID: PMC8260486 DOI: 10.1002/jmd2.12213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/25/2022] Open
Abstract
MAN1B1-CDG is a multisystem disorder caused by mutations in MAN1B1, encoding the endoplasmic reticulum mannosyl-oligosaccharide alpha-1,2-mannnosidase. A defect leads to dysfunction within the degradation of misfolded glycoproteins. We present two additional patients with MAN1B1-CDG and a resulting defect in endoplasmic reticulum-associated protein degradation. One patient (P2) is carrying the previously undescribed p.E663K mutation. A therapeutic trial in patient 1 (P1) using disulfiram with the rationale to generate an attenuation of translation and thus a balanced, restored ER glycoprotein synthesis failed. No improvement of the transferrin glycosylation profile was seen.
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Affiliation(s)
- Lisa Kemme
- University Children's Hospital MünsterMuensterGermany
| | | | | | - Stephan Rust
- University Children's Hospital MünsterMuensterGermany
| | - Julien Park
- University Children's Hospital MünsterMuensterGermany
- Department of Clinical Sciences, NeurosciencesUmeå UniversityUmeåSweden
| | - Cordula Westermann
- Gerhard‐Domagk‐Institute of PathologyUniversity Hospital MuensterMuensterGermany
| | - Yoshinao Wada
- Osaka Medical Center and Research Institute for Maternal and Child HealthOsakaJapan
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Unconventional p97/VCP-Mediated Endoplasmic Reticulum-to-Endosome Trafficking of a Retroviral Protein. J Virol 2021; 95:e0053121. [PMID: 33952644 DOI: 10.1128/jvi.00531-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) encodes a Rem precursor protein that specifies both regulatory and accessory functions. Rem is cleaved at the endoplasmic reticulum (ER) membrane into a functional N-terminal signal peptide (SP) and the C terminus (Rem-CT). Rem-CT lacks a membrane-spanning domain and a known ER retention signal, and yet it was not detectably secreted into cell supernatants. Inhibition of intracellular trafficking by the drug brefeldin A (BFA), which interferes with the ER-to-Golgi secretory pathway, resulted in dramatically reduced intracellular Rem-CT levels that were not rescued by proteasomal or lysosomal inhibitors. A Rem mutant lacking glycosylation was cleaved into SP and Rem-CT but was insensitive to BFA, suggesting that unglycosylated Rem-CT does not reach this BFA-dependent compartment. Treatment with endoglycosidase H indicated that Rem-CT does not traffic through the Golgi apparatus. Analysis of wild-type Rem-CT and its glycosylation mutant by confocal microscopy revealed that both were primarily localized to the ER lumen. A small fraction of wild-type Rem-CT, but not the unglycosylated mutant, was colocalized with Rab5-positive (Rab5+) early endosomes. The expression of a dominant-negative (DN) form of ADP ribosylation factor 1 (Arf1) (containing a mutation of threonine to asparagine at position 31 [T31N]) mimicked the effects of BFA by reducing Rem-CT levels and increased Rem-CT association with early and late endosomes. Inhibition of the AAA ATPase p97/VCP rescued Rem-CT in the presence of BFA or DN Arf1 and prevented localization to Rab5+ endosomes. Thus, Rem-CT uses an unconventional p97-mediated scheme for trafficking to early endosomes. IMPORTANCE Mouse mammary tumor virus is a complex retrovirus that encodes a regulatory/accessory protein, Rem. Rem is a precursor protein that is processed at the endoplasmic reticulum (ER) membrane by signal peptidase. The N-terminal SP uses the p97/VCP ATPase to elude ER-associated degradation to traffic to the nucleus and serve a human immunodeficiency virus Rev-like function. In contrast, the function of the C-terminal glycosylated cleavage product (Rem-CT) is unknown. Since localization is critical for protein function, we used mutants, inhibitors, and confocal microscopy to localize Rem-CT. Surprisingly, Rem-CT, which lacks a transmembrane domain or an ER retention signal, was detected primarily within the ER and required glycosylation and the p97 ATPase for early endosome trafficking without passage through the Golgi apparatus. Thus, Rem-CT uses a novel intracellular trafficking pathway, potentially impacting host antiviral immunity.
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Ninagawa S. N-glycan Dependent Protein Quality Control System in the Endoplasmic Reticulum. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2108.2e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University
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Ninagawa S. N-glycan Dependent Protein Quality Control System in the Endoplasmic Reticulum. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2108.2j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University
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13
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Differential Effects of STCH and Stress-Inducible Hsp70 on the Stability and Maturation of NKCC2. Int J Mol Sci 2021. [PMID: 33672238 DOI: 10.3390/ijms22042207.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mutations in the Na-K-2Cl co-transporter NKCC2 lead to type I Bartter syndrome, a life-threatening kidney disease. We previously showed that export from the ER constitutes the limiting step in NKCC2 maturation and cell surface expression. Yet, the molecular mechanisms involved in this process remain obscure. Here, we report the identification of chaperone stress 70 protein (STCH) and the stress-inducible heat shock protein 70 (Hsp70), as two novel binding partners of the ER-resident form of NKCC2. STCH knock-down increased total NKCC2 expression whereas Hsp70 knock-down or its inhibition by YM-01 had the opposite effect. Accordingly, overexpressing of STCH and Hsp70 exerted opposite actions on total protein abundance of NKCC2 and its folding mutants. Cycloheximide chase assay showed that in cells over-expressing STCH, NKCC2 stability and maturation are heavily impaired. In contrast to STCH, Hsp70 co-expression increased NKCC2 maturation. Interestingly, treatment by protein degradation inhibitors revealed that in addition to the proteasome, the ER associated degradation (ERAD) of NKCC2 mediated by STCH, involves also the ER-to-lysosome-associated degradation pathway. In summary, our data are consistent with STCH and Hsp70 having differential and antagonistic effects with regard to NKCC2 biogenesis. These findings may have an impact on our understanding and potential treatment of diseases related to aberrant NKCC2 trafficking and expression.
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Differential Effects of STCH and Stress-Inducible Hsp70 on the Stability and Maturation of NKCC2. Int J Mol Sci 2021; 22:ijms22042207. [PMID: 33672238 PMCID: PMC7926544 DOI: 10.3390/ijms22042207] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/13/2021] [Accepted: 02/20/2021] [Indexed: 12/16/2022] Open
Abstract
Mutations in the Na-K-2Cl co-transporter NKCC2 lead to type I Bartter syndrome, a life-threatening kidney disease. We previously showed that export from the ER constitutes the limiting step in NKCC2 maturation and cell surface expression. Yet, the molecular mechanisms involved in this process remain obscure. Here, we report the identification of chaperone stress 70 protein (STCH) and the stress-inducible heat shock protein 70 (Hsp70), as two novel binding partners of the ER-resident form of NKCC2. STCH knock-down increased total NKCC2 expression whereas Hsp70 knock-down or its inhibition by YM-01 had the opposite effect. Accordingly, overexpressing of STCH and Hsp70 exerted opposite actions on total protein abundance of NKCC2 and its folding mutants. Cycloheximide chase assay showed that in cells over-expressing STCH, NKCC2 stability and maturation are heavily impaired. In contrast to STCH, Hsp70 co-expression increased NKCC2 maturation. Interestingly, treatment by protein degradation inhibitors revealed that in addition to the proteasome, the ER associated degradation (ERAD) of NKCC2 mediated by STCH, involves also the ER-to-lysosome-associated degradation pathway. In summary, our data are consistent with STCH and Hsp70 having differential and antagonistic effects with regard to NKCC2 biogenesis. These findings may have an impact on our understanding and potential treatment of diseases related to aberrant NKCC2 trafficking and expression.
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Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
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The cytoplasmic tail of human mannosidase Man1b1 contributes to catalysis-independent quality control of misfolded alpha1-antitrypsin. Proc Natl Acad Sci U S A 2020; 117:24825-24836. [PMID: 32958677 DOI: 10.1073/pnas.1919013117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The failure of polypeptides to achieve conformational maturation following biosynthesis can result in the formation of protein aggregates capable of disrupting essential cellular functions. In the secretory pathway, misfolded asparagine (N)-linked glycoproteins are selectively sorted for endoplasmic reticulum-associated degradation (ERAD) in response to the catalytic removal of terminal alpha-linked mannose units. Remarkably, ER mannosidase I/Man1b1, the first alpha-mannosidase implicated in this conventional N-glycan-mediated process, can also contribute to ERAD in an unconventional, catalysis-independent manner. To interrogate this functional dichotomy, the intracellular fates of two naturally occurring misfolded N-glycosylated variants of human alpha1-antitrypsin (AAT), Null Hong Kong (NHK), and Z (ATZ), in Man1b1 knockout HEK293T cells were monitored in response to mutated or truncated forms of transfected Man1b1. As expected, the conventional catalytic system requires an intact active site in the Man1b1 luminal domain. In contrast, the unconventional system is under the control of an evolutionarily extended N-terminal cytoplasmic tail. Also, N-glycans attached to misfolded AAT are not required for accelerated degradation mediated by the unconventional system, further demonstrating its catalysis-independent nature. We also established that both systems accelerate the proteasomal degradation of NHK in metabolic pulse-chase labeling studies. Taken together, these results have identified the previously unrecognized regulatory capacity of the Man1b1 cytoplasmic tail and provided insight into the functional dichotomy of Man1b1 as a component in the mammalian proteostasis network.
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Zhang J, Wu J, Liu L, Li J. The Crucial Role of Demannosylating Asparagine-Linked Glycans in ERADicating Misfolded Glycoproteins in the Endoplasmic Reticulum. FRONTIERS IN PLANT SCIENCE 2020; 11:625033. [PMID: 33510762 PMCID: PMC7835635 DOI: 10.3389/fpls.2020.625033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 12/08/2020] [Indexed: 05/04/2023]
Abstract
Most membrane and secreted proteins are glycosylated on certain asparagine (N) residues in the endoplasmic reticulum (ER), which is crucial for their correct folding and function. Protein folding is a fundamentally inefficient and error-prone process that can be easily interfered by genetic mutations, stochastic cellular events, and environmental stresses. Because misfolded proteins not only lead to functional deficiency but also produce gain-of-function cellular toxicity, eukaryotic organisms have evolved highly conserved ER-mediated protein quality control (ERQC) mechanisms to monitor protein folding, retain and repair incompletely folded or misfolded proteins, or remove terminally misfolded proteins via a unique ER-associated degradation (ERAD) mechanism. A crucial event that terminates futile refolding attempts of a misfolded glycoprotein and diverts it into the ERAD pathway is executed by removal of certain terminal α1,2-mannose (Man) residues of their N-glycans. Earlier studies were centered around an ER-type α1,2-mannosidase that specifically cleaves the terminal α1,2Man residue from the B-branch of the three-branched N-linked Man9GlcNAc2 (GlcNAc for N-acetylglucosamine) glycan, but recent investigations revealed that the signal that marks a terminally misfolded glycoprotein for ERAD is an N-glycan with an exposed α1,6Man residue generated by members of a unique folding-sensitive α1,2-mannosidase family known as ER-degradation enhancing α-mannosidase-like proteins (EDEMs). This review provides a historical recount of major discoveries that led to our current understanding on the role of demannosylating N-glycans in sentencing irreparable misfolded glycoproteins into ERAD. It also discusses conserved and distinct features of the demannosylation processes of the ERAD systems of yeast, mammals, and plants.
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Affiliation(s)
- Jianjun Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jiarui Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Linchuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jianming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Jianming Li, ;
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Lim B, Kydd L, Jaworski J. A Peptide-Lectin Fusion Strategy for Developing a Glycan Probe for Use in Various Assay Formats. CHEMOSENSORS 2019; 7. [PMID: 32793433 PMCID: PMC7423246 DOI: 10.3390/chemosensors7040055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While nucleic acid and protein analysis approaches continue to see significant breakthroughs, analytical strategies for glycan determination have by comparison seen slower technological advances. Here we provide a strategy for glycan probe development using an engineered lectin fusion that can be incorporated into various common pathology lab assay formats including Western blot and agglutination assays. In this proof of concept, we use the natural lectin, Pseudomonas fluorescens agglutinin (PFA), capable of binding core Man alpha(1-3)-Man alpha(1-6)-Man units, where this lectin has previously been shown to bind to the glycans presented by the gp120 coat protein of (HIV) Human Immunodeficiency Virus. In our strategy, we engineered the lectin to possess a fusion of the biotin mimetic tag equence of amino acids V-S-H-P-Q-A-P-F. With the glycan receptive PFA directly linked to the biotin mimic, we could facilitate a probe for various standard clinical assay formats by virtue of coupling to streptavidin-HRP (horseradish peroxidase) or streptavidin beads for Western blot and agglutination assays respectively. We found the PFA fusion retained low nanomolar affinity for gp120 by ELISA (Enzyme Linked Immunosorbent Assay) and microscale thermophoresis. This probe engineering strategy proved effective in the relevant assay formats that may now allow detection for the presence of glycans containing the core Man alpha(1-3)-Man alpha(1-6)-Man units recognized by PFA.
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Anelli T, Panina-Bordignon P. How to Avoid a No-Deal ER Exit. Cells 2019; 8:cells8091051. [PMID: 31500301 PMCID: PMC6769657 DOI: 10.3390/cells8091051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 08/28/2019] [Accepted: 09/06/2019] [Indexed: 01/01/2023] Open
Abstract
Efficiency and fidelity of protein secretion are achieved thanks to the presence of different steps, located sequentially in time and space along the secretory compartment, controlling protein folding and maturation. After entering into the endoplasmic reticulum (ER), secretory proteins attain their native structure thanks to specific chaperones and enzymes. Only correctly folded molecules are allowed by quality control (QC) mechanisms to leave the ER and proceed to downstream compartments. Proteins that cannot fold properly are instead retained in the ER to be finally destined to proteasomal degradation. Exiting from the ER requires, in most cases, the use of coated vesicles, departing at the ER exit sites, which will fuse with the Golgi compartment, thus releasing their cargoes. Protein accumulation in the ER can be caused by a too stringent QC or by ineffective transport: these situations could be deleterious for the organism, due to the loss of the secreted protein, and to the cell itself, because of abnormal increase of protein concentration in the ER. In both cases, diseases can arise. In this review, we will describe the pathophysiology of protein folding and transport between the ER and the Golgi compartment.
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Affiliation(s)
- Tiziana Anelli
- Vita-Salute San Raffaele University, 20132 Milan, Italy.
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
| | - Paola Panina-Bordignon
- Vita-Salute San Raffaele University, 20132 Milan, Italy.
- Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
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A signal motif retains Arabidopsis ER-α-mannosidase I in the cis-Golgi and prevents enhanced glycoprotein ERAD. Nat Commun 2019; 10:3701. [PMID: 31420549 PMCID: PMC6697737 DOI: 10.1038/s41467-019-11686-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 07/01/2019] [Indexed: 11/09/2022] Open
Abstract
The Arabidopsis ER-α-mannosidase I (MNS3) generates an oligomannosidic N-glycan structure that is characteristically found on ER-resident glycoproteins. The enzyme itself has so far not been detected in the ER. Here, we provide evidence that in plants MNS3 exclusively resides in the Golgi apparatus at steady-state. Notably, MNS3 remains on dispersed punctate structures when subjected to different approaches that commonly result in the relocation of Golgi enzymes to the ER. Responsible for this rare behavior is an amino acid signal motif (LPYS) within the cytoplasmic tail of MNS3 that acts as a specific Golgi retention signal. This retention is a means to spatially separate MNS3 from ER-localized mannose trimming steps that generate the glycan signal required for flagging terminally misfolded glycoproteins for ERAD. The physiological importance of the very specific MNS3 localization is demonstrated here by means of a structurally impaired variant of the brassinosteroid receptor BRASSINOSTEROID INSENSITIVE 1. The Arabidopsis ER-α-mannosidase I MNS3 generates N-glycan structures typical of ER-resident glycoproteins. Here Schoberer et al. identify a novel motif that anchors MNS3 to the cis-Golgi, spatially separating MNS3 from ER-localized mannose trimming associated with the ER-associated degradation pathway.
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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: 81] [Impact Index Per Article: 16.2] [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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The Best for the Most Important: Maintaining a Pristine Proteome in Stem and Progenitor Cells. Stem Cells Int 2019; 2019:1608787. [PMID: 31191665 PMCID: PMC6525796 DOI: 10.1155/2019/1608787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/05/2019] [Indexed: 12/19/2022] Open
Abstract
Pluripotent stem cells give rise to reproductively enabled offsprings by generating progressively lineage-restricted multipotent stem cells that would differentiate into lineage-committed stem and progenitor cells. These lineage-committed stem and progenitor cells give rise to all adult tissues and organs. Adult stem and progenitor cells are generated as part of the developmental program and play critical roles in tissue and organ maintenance and/or regeneration. The ability of pluripotent stem cells to self-renew, maintain pluripotency, and differentiate into a multicellular organism is highly dependent on sensing and integrating extracellular and extraorganismal cues. Proteins perform and integrate almost all cellular functions including signal transduction, regulation of gene expression, metabolism, and cell division and death. Therefore, maintenance of an appropriate mix of correctly folded proteins, a pristine proteome, is essential for proper stem cell function. The stem cells' proteome must be pristine because unfolded, misfolded, or otherwise damaged proteins would interfere with unlimited self-renewal, maintenance of pluripotency, differentiation into downstream lineages, and consequently with the development of properly functioning tissue and organs. Understanding how various stem cells generate and maintain a pristine proteome is therefore essential for exploiting their potential in regenerative medicine and possibly for the discovery of novel approaches for maintaining, propagating, and differentiating pluripotent, multipotent, and adult stem cells as well as induced pluripotent stem cells. In this review, we will summarize cellular networks used by various stem cells for generation and maintenance of a pristine proteome. We will also explore the coordination of these networks with one another and their integration with the gene regulatory and signaling networks.
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Li H, Wang G, Yu Y, Jian W, Zhang D, Wang Y, Wang T, Meng Y, Yuan C, Zhang C. α-1,2-Mannosidase MAN1C1 Inhibits Proliferation and Invasion of Clear Cell Renal Cell Carcinoma. J Cancer 2018; 9:4618-4626. [PMID: 30588245 PMCID: PMC6299394 DOI: 10.7150/jca.27673] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/01/2018] [Indexed: 01/08/2023] Open
Abstract
Background: This study investigated the biological function of the gene MAN1C1 α-mannosidase in renal cell carcinoma. It has been reported that MAN1C1 is probably a potential tumor suppressor gene in Wilms. However, the role of MAN1C1 in human clear cell renal cell carcinoma (ccRCC) has not been reported. Methods: In this study, MAN1C1 gene over-expression was used to transfect human renal cancer cell lines 786-O and OS-RC-2 to study apoptosis and the underlying mechanisms which influence epithelial-mesenchymal transition. Results: MAN1C1 was down-regulated in ccRCC and related to the clinicopathological factors and prognosis of ccRCC. We revealed that over-expression MAN1C1 showed anti-tumor effect by inducing apoptosis, as determined by Cell Counting Kit-8 (CCK-8) assay, cell cycle analysis, and western blot analysis. What's more, MAN1C1 over-expression remarkably increased the ratio of Bax/Bcl-2 and inhibited epithelial-mesenchymal transition by increasing the expression of E-CA. In addition, the ratio of Bax/Bcl-2 and E-CA were also increased in MAN1C1 gene over-expression renal cancer cells compared with the control cells. Conclusion: We find that re-expression of silenced MAN1C1 in ccRCC cell lines inhibited cell viability, colony formation, induced apoptosis, suppressed cell invasion and migration. In conclusion, MAN1C1 is a novel functional tumor suppressor in renal carcinogenesis. This is the first time that the function of MAN1C1 gene has been verified in the renal tumor tissue so far.
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Affiliation(s)
- Haoming Li
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Gang Wang
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yipeng Yu
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Wengang Jian
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Daming Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yongquan Wang
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Tengda Wang
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yuyang Meng
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Chao Yuan
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Cheng Zhang
- Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
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Abstract
Alpha-1 antitrypsin deficiency is predominantly caused by point mutations that alter the protein's folding. These mutations fall into two broad categories: those that destabilize the protein dramatically and lead to its post-translational degradation and those that affect protein structure more subtly to promote protein polymerization within the endoplasmic reticulum (ER). This distinction is important because it determines the cell's response to each mutant. The severely misfolded mutants trigger an unfolded protein response (UPR) that promotes improved protein folding but can kill the cell in the chronic setting. In contrast, mutations that permit polymer formation fail to activate the UPR but instead promote a nuclear factor-κB-mediated ER overload response. The ability of polymers to increase a cell's sensitivity to ER stress likely explains apparent inconsistencies in the alpha-1 antitrypsin-signaling literature that have linked polymers with the UPR. In this review we discuss the use of mutant serpins to dissect each signaling pathway.
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γ-COPI mediates the retention of kAE1 G701D protein in Golgi apparatus – a mechanistic explanation of distal renal tubular acidosis associated with the G701D mutation. Biochem J 2017. [DOI: 10.1042/bcj20170088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mutations of the solute carrier family 4 member 1 (SLC4A1) gene encoding kidney anion (chloride/bicarbonate ion) exchanger 1 (kAE1) can cause genetic distal renal tubular acidosis (dRTA). Different SLC4A1 mutations give rise to mutant kAE1 proteins with distinct defects in protein trafficking. The mutant kAE1 protein may be retained in endoplasmic reticulum (ER) or Golgi apparatus, or mis-targeted to the apical membrane, failing to display its function at the baso-lateral membrane. The ER-retained mutant kAE1 interacts with calnexin chaperone protein; disruption of this interaction permits the mutant kAE1 to reach the cell surface and display anion exchange activity. However, the mechanism of Golgi retention of mutant kAE1 G701D protein, which is otherwise functional, is still unclear. In the present study, we show that Golgi retention of kAE1 G701D is due to a stable interaction with the Golgi-resident protein, coat protein complex I (COPI), that plays a role in retrograde vesicular trafficking and Golgi-based quality control. The interaction and co-localization of kAE1 G701D with the γ-COPI subunit were demonstrated in human embryonic kidney (HEK-293T) cells by co-immunoprecipitation and immunofluorescence staining. Small interference RNA (siRNA) silencing of COPI expression in the transfected HEK-293T cells increased the cell surface expression of transgenic kAE1 G701D, as shown by immunofluorescence staining. Our data unveil the molecular mechanism of Golgi retention of kAE1 G701D and suggest that disruption of the COPI-kAE1 G701D interaction could be a therapeutic strategy to treat dRTA caused by this mutant.
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Tu HC, Hsiao YC, Yang WY, Tsai SL, Lin HK, Liao CY, Lu JW, Chou YT, Wang HD, Yuh CH. Up-regulation of golgi α-mannosidase IA and down-regulation of golgi α-mannosidase IC activates unfolded protein response during hepatocarcinogenesis. Hepatol Commun 2017; 1:230-247. [PMID: 29404456 PMCID: PMC5721452 DOI: 10.1002/hep4.1032] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/27/2017] [Accepted: 03/09/2017] [Indexed: 12/27/2022] Open
Abstract
α‐1,2 mannosidases, key enzymes in N‐glycosylation, are required for the formation of mature glycoproteins in eukaryotes. Aberrant regulation of α‐1,2 mannosidases can result in cancer, although the underlying mechanisms are unclear. Here, we report the distinct roles of α‐1,2 mannosidase subtypes (MAN1A, MAN1B, ERMAN1, MAN1C) in the formation of hepatocellular carcinoma (HCC). Clinicopathological analyses revealed that the clinical stage, tumor size, α‐fetoprotein level, and invasion status were positively correlated with the expression levels of MAN1A1, MAN1B1, and MAN1A2. In contrast, the expression of MAN1C1 was decreased as early as stage I of HCC. Survival analyses showed that high MAN1A1, MAN1A2, and MAN1B1 expression levels combined with low MAN1C1 expression levels were significantly correlated with shorter overall survival rates. Functionally, the overexpression of MAN1A1 promoted proliferation, migration, and transformation as well as in vivo migration in zebrafish. Conversely, overexpression of MAN1C1 reduced the migration ability both in vitro and in vivo, decreased the colony formation ability, and shortened the S phase of the cell cycle. Furthermore, the expression of genes involved in cell cycle/proliferation and migration was increased in MAN1A1‐overexpressing cells but decreased in MAN1C1‐overexpressing cells. MAN1A1 activated the expression of key regulators of the unfolded protein response (UPR), while treatment with endoplasmic reticulum stress inhibitors blocked the expression of MAN1A1‐activated genes. Using the MAN1A1 liver‐specific overexpression zebrafish model, we observed steatosis and inflammation at earlier stages and HCC formation at a later stage accompanied by the increased expression of the UPR modulator binding immunoglobulin protein (BiP). These data suggest that the up‐regulation of MAN1A1 activates the UPR and might initiate metastasis. Conclusion: MAN1A1 represents a novel oncogene while MAN1C1 plays a role in tumor suppression in hepatocarcinogenesis. (Hepatology Communications 2017;1:230‐247)
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Affiliation(s)
- Hsiao-Chen Tu
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Institute of Biotechnology National Tsing-Hua University Hsinchu Taiwan
| | - Yung-Chun Hsiao
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Institute of Biotechnology National Tsing-Hua University Hsinchu Taiwan
| | - Wan-Yu Yang
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan
| | - Shin-Lin Tsai
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan
| | - Hua-Kuo Lin
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan
| | - Chong-Yi Liao
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Institute of Biotechnology National Tsing-Hua University Hsinchu Taiwan
| | - Jeng-Wei Lu
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Department of Life Sciences National Central University Jhongli City Taoyuan Taiwan
| | - Yu-Ting Chou
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Institute of Biotechnology National Tsing-Hua University Hsinchu Taiwan
| | - Horng-Dar Wang
- Institute of Biotechnology National Tsing-Hua University Hsinchu Taiwan
| | - Chiou-Hwa Yuh
- Institute of Molecular and Genomic Medicine National Health Research Institutes Zhunan Miaoli Taiwan.,Institute of Bioinformatics and Structural Biology National Tsing-Hua University Hsinchu Taiwan.,Department of Biological Science and Technology National Chiao Tung University Hsinchu Taiwan.,Kaohsiung Medical University Kaohsiung Taiwan
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Gupta S, Fahiminiya S, Wang T, Dempsey Nunez L, Rosenblatt DS, Gibson WT, Gilfix B, Bergeron JJM, Jerome-Majewska LA. Somatic overgrowth associated with homozygous mutations in both MAN1B1 and SEC23A. Cold Spring Harb Mol Case Stud 2016; 2:a000737. [PMID: 27148587 PMCID: PMC4853519 DOI: 10.1101/mcs.a000737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Using whole-exome sequencing, we identified homozygous mutations in two unlinked genes, SEC23A c.1200G>C (p.M400I) and MAN1B1 c.1000C>T (p.R334C), associated with congenital birth defects in two patients from a consanguineous family. Patients presented with carbohydrate-deficient transferrin, tall stature, obesity, macrocephaly, and maloccluded teeth. The parents were healthy heterozygous carriers for both mutations and an unaffected sibling with tall stature carried the heterozygous mutation in SEC23A only. Mutations in SEC23A are responsible for craniolenticosultura dysplasia (CLSD). CLSD patients are short, have late-closing fontanels, and have reduced procollagen (pro-COL1A1) secretion because of abnormal pro-COL1A1 retention in the endoplasmic reticulum (ER). The mutation we identified in MAN1B1 was previously associated with reduced MAN1B1 protein and congenital disorders of glycosylation (CDG). CDG patients are also short, are obese, and have abnormal glycan remodeling. Molecular analysis of fibroblasts from the family revealed normal levels of SEC23A in all cells and reduced levels of MAN1B1 in cells with heterozygous or homozygous mutations in SEC23A and MAN1B1. Secretion of pro-COL1A1 was increased in fibroblasts from the siblings and patients, and pro-COL1A1 was retained in Golgi of heterozygous and homozygous mutant cells, although intracellular pro-COL1A1 was increased in patient fibroblasts only. We postulate that increased pro-COL1A1 secretion is responsible for tall stature in these patients and an unaffected sibling, and not previously discovered in patients with mutations in either SEC23A or MAN1B1. The patients in this study share biochemical and cellular characteristics consistent with mutations in MAN1B1 and SEC23A, indicating a digenic disease.
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Affiliation(s)
- Swati Gupta
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Somayyeh Fahiminiya
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Tracy Wang
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Laura Dempsey Nunez
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - David S Rosenblatt
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada;; Department of Pediatrics, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - William T Gibson
- Department of Medical Genetics, Child and Family Research Institute, Vancouver, British Columbia V6H 3V4, Canada
| | - Brian Gilfix
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - John J M Bergeron
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Loydie A Jerome-Majewska
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada;; Department of Pediatrics, McGill University, Montreal, Quebec H4A 3J1, Canada;; Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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28
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Xu C, Ng DTW. Glycosylation-directed quality control of protein folding. Nat Rev Mol Cell Biol 2015; 16:742-52. [PMID: 26465718 DOI: 10.1038/nrm4073] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Membrane-bound and soluble proteins of the secretory pathway are commonly glycosylated in the endoplasmic reticulum. These adducts have many biological functions, including, notably, their contribution to the maturation of glycoproteins. N-linked glycans are of oligomeric structure, forming configurations that provide blueprints to precisely instruct the folding of protein substrates and the quality control systems that scrutinize it. O-linked mannoses are simpler in structure and were recently found to have distinct functions in protein quality control that do not require the complex structure of N-linked glycans. Together, recent studies reveal the breadth and sophistication of the roles of these glycan-directed modifications in protein biogenesis.
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Affiliation(s)
- Chengchao Xu
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Davis T W Ng
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.,Duke University-National University of Singapore Graduate Medical School, 8 College Road, Singapore 169857
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Tewari R, Bachert C, Linstedt AD. Induced oligomerization targets Golgi proteins for degradation in lysosomes. Mol Biol Cell 2015; 26:4427-37. [PMID: 26446839 PMCID: PMC4666137 DOI: 10.1091/mbc.e15-04-0207] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/29/2015] [Indexed: 01/07/2023] Open
Abstract
Oligomerization or homotypic clustering diverts Golgi membrane proteins into the canonical GGA1/clathrin-dependent Golgi-to-lysosome pathway revealing the presence of cellular quality control that could be useful for therapies designed to down-regulate specific proteins in the secretory pathway. Manganese protects cells against forms of Shiga toxin by down-regulating the cycling Golgi protein GPP130. Down-regulation occurs when Mn binding causes GPP130 to oligomerize and traffic to lysosomes. To determine how GPP130 is redirected to lysosomes, we tested the role of GGA1 and clathrin, which mediate sorting in the canonical Golgi-to-lysosome pathway. GPP130 oligomerization was induced using either Mn or a self-interacting version of the FKBP domain. Inhibition of GGA1 or clathrin specifically blocked GPP130 redistribution, suggesting recognition of the aggregated GPP130 by the GGA1/clathrin-sorting complex. Unexpectedly, however, GPP130’s cytoplasmic domain was not required, and redistribution also occurred after removal of GPP130 sequences needed for its normal cycling. Therefore, to test whether aggregate recognition might be a general phenomenon rather than one involving a specific GPP130 determinant, we induced homo-oligomerization of two unrelated Golgi-targeted constructs using the FKBP strategy. These were targeted to the cis- and trans-Golgi, respectively, using domains from mannosidase-1 and galactosyltransferase. Significantly, upon oligomerization, each redistributed to peripheral punctae and was degraded. This occurred in the absence of detectable UPR activation. These findings suggest the unexpected presence of quality control in the Golgi that recognizes aggregated Golgi proteins and targets them for degradation in lysosomes.
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Affiliation(s)
- Ritika Tewari
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Collin Bachert
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adam D Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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30
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Ondrušková N, Honzík T, Kytnarová J, Matoulek M, Zeman J, Hansíková H. Isoelectric Focusing of Serum Apolipoprotein C-III as a Sensitive Screening Method for the Detection of O-glycosylation Disturbances. Prague Med Rep 2015; 116:73-86. [PMID: 26093664 DOI: 10.14712/23362936.2015.48] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Apolipoprotein C-III (ApoC-III) is a glycoprotein carrying the most common O-linked glycan structure and is abundantly present in serum, what renders it a suitable marker for analysis of O-glycosylation abnormalities. Isoelectric focusing followed by a Western blot of ApoC-III, using PhastSystem™ Electrophoresis System (GE Healthcare), was introduced as a rather simple and rapid method for screening of certain subtypes of inherited glycosylation disorders. The study's aim was to establish this method in our laboratory, what included performing the analysis in a group of 170 healthy individuals to set the reference range of detected relative amounts of sialylated ApoC-III isoforms and to evaluate the gender- and age-dependent differences. A significant relative increase of asialo-ApoC-III with growing age was found. Secondly, we examined serum from patients with selected metabolic disorders and detected minor O-glycosylation changes in diseases such as Prader-Willi syndrome, PGM1 (phosphoglucomutase 1) or MAN1B (class 1B alpha-1,2-mannosidase) deficiency. Our results show that this method allows for a sensitive detection of ApoC-III O-glycosylation status, however this might be modulated by several factors (i.e. nutrition, medication) whose exact role remains to be determined.
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Affiliation(s)
- Nina Ondrušková
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Tomáš Honzík
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Jitka Kytnarová
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Martin Matoulek
- 3rd Department of Medicine - Department of Endocrinology and Metabolism, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Jiří Zeman
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Hana Hansíková
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic.
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31
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Słomińska-Wojewódzka M, Sandvig K. The Role of Lectin-Carbohydrate Interactions in the Regulation of ER-Associated Protein Degradation. Molecules 2015; 20:9816-46. [PMID: 26023941 PMCID: PMC6272441 DOI: 10.3390/molecules20069816] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 01/08/2023] Open
Abstract
Proteins entering the secretory pathway are translocated across the endoplasmic reticulum (ER) membrane in an unfolded form. In the ER they are restricted to a quality control system that ensures correct folding or eventual degradation of improperly folded polypeptides. Mannose trimming of N-glycans on newly synthesized proteins plays an important role in the recognition and sorting of terminally misfolded glycoproteins for ER-associated protein degradation (ERAD). In this process misfolded proteins are retrotranslocated into the cytosol, polyubiquitinated, and eventually degraded by the proteasome. The mechanism by which misfolded glycoproteins are recognized and recruited to the degradation machinery has been extensively studied during last decade. In this review, we focus on ER degradation-enhancing α-mannosidase-like protein (EDEM) family proteins that seem to play a key role in the discrimination between proteins undergoing a folding process and terminally misfolded proteins directed for degradation. We describe interactions of EDEM proteins with other components of the ERAD machinery, as well as with various protein substrates. Carbohydrate-dependent interactions together with N-glycan-independent interactions seem to regulate the complex process of protein recognition and direction for proteosomal degradation.
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Affiliation(s)
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, 0379 Oslo, Norway.
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway.
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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32
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Wang D, Ma J, Sun D, Li H, Jiang C, Li X. Expression of bioactive anti-CD20 antibody fragments and induction of ER stress response in Arabidopsis seeds. Appl Microbiol Biotechnol 2015; 99:6753-64. [PMID: 25957150 DOI: 10.1007/s00253-015-6601-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/01/2015] [Accepted: 04/05/2015] [Indexed: 11/25/2022]
Abstract
Seed-based expression system is an attractive platform for the production of recombinant proteins in molecular farming. Despite the many advantages of molecular farming, little is known about the effect of the different subcellular accumulation of recombinant proteins on the endoplasmic reticulum (ER) quality control system in host plants. In this study, we analyzed the expression of anti-CD20 antibody fragments in seeds of Arabidopsis thaliana (ecotype Columbia) and corresponding glycosylation mutants, and evaluated the influence of three different signal sequences on the expression levels of scFv-Fc of C2B8. The highest protein accumulation level, with a maximum of 6.12 % total soluble proteins, was observed upon fusing proteins to the signal peptide of Arabidopsis seed storage albumin 2. The ER stress responses in developing seeds at 13 days post-anthesis were also compared across different transgenic lines under normal and heat shock conditions. Based on the gene expression profiles of ER stress transducers, our results suggest that accumulation of antibody fragments in the ER exerts more stress on ER homeostasis. In addition, quantitative PCR results also implicate enhanced activation of ER-associated degradation in transgenic lines. Last but not the least, we also demonstrate the anti-tumor potency of plant-derived proteins by showing the anti-tumor activity of purified scFv-Fc proteins against Daudi cells. Together, our data implies that better understanding of the interaction between exogenous protein production and the cellular quality control system of the host plant is necessary for the development of an optimal expression strategy that will be especially beneficial to commercial protein manufacturing.
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Affiliation(s)
- Dezhong Wang
- College of Life Sciences, Jilin University, Changchun, 130021, China
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33
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Au CE, Hermo L, Byrne E, Smirle J, Fazel A, Simon PHG, Kearney RE, Cameron PH, Smith CE, Vali H, Fernandez-Rodriguez J, Ma K, Nilsson T, Bergeron JJM. Expression, sorting, and segregation of Golgi proteins during germ cell differentiation in the testis. Mol Biol Cell 2015; 26:4015-32. [PMID: 25808494 PMCID: PMC4710233 DOI: 10.1091/mbc.e14-12-1632] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/19/2015] [Indexed: 12/14/2022] Open
Abstract
A total of 1318 proteins characterized in the male germ cell Golgi apparatus reveal a new germ cell–specific Golgi marker and a new pan-Golgi marker for all cells. The localization of these and other Golgi proteins reveals differential expression linked to mitosis, meiosis, acrosome formation, and postacrosome Golgi migration and destination in the late spermatid. The molecular basis of changes in structure, cellular location, and function of the Golgi apparatus during male germ cell differentiation is unknown. To deduce cognate Golgi proteins, we isolated germ cell Golgi fractions, and 1318 proteins were characterized, with 20 localized in situ. The most abundant protein, GL54D of unknown function, is characterized as a germ cell–specific Golgi-localized type II integral membrane glycoprotein. TM9SF3, also of unknown function, was revealed to be a universal Golgi marker for both somatic and germ cells. During acrosome formation, several Golgi proteins (GBF1, GPP34, GRASP55) localize to both the acrosome and Golgi, while GL54D, TM9SF3, and the Golgi trafficking protein TMED7/p27 are segregated from the acrosome. After acrosome formation, GL54D, TM9SF3, TMED4/p25, and TMED7/p27 continue to mark Golgi identity as it migrates away from the acrosome, while the others (GBF1, GPP34, GRASP55) remain in the acrosome and are progressively lost in later steps of differentiation. Cytoplasmic HSP70.2 and the endoplasmic reticulum luminal protein-folding enzyme PDILT are also Golgi recruited but only during acrosome formation. This resource identifies abundant Golgi proteins that are expressed differentially during mitosis, meiosis, and postacrosome Golgi migration, including the last step of differentiation.
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Affiliation(s)
- Catherine E Au
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Louis Hermo
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | - Elliot Byrne
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Jeffrey Smirle
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Ali Fazel
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Paul H G Simon
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Robert E Kearney
- Department of Biomedical Engineering Department, McGill University, Montreal, QC H3A 2B4, Canada
| | - Pamela H Cameron
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Charles E Smith
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | - Hojatollah Vali
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | - Julia Fernandez-Rodriguez
- Centre for Cellular Imaging, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Kewei Ma
- Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - Tommy Nilsson
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
| | - John J M Bergeron
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada Division of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada
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Sun L, Hartson SD, Matts RL. Identification of proteins associated with Aha1 in HeLa cells by quantitative proteomics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:365-80. [PMID: 25614414 DOI: 10.1016/j.bbapap.2015.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/20/2014] [Accepted: 01/09/2015] [Indexed: 01/17/2023]
Abstract
The identification of the activator of heat shock protein 90 (Hsp90) ATPase's (Aha1) protein-protein interaction (PPI) network will provide critical insights into the relationship of Aha1 with multi-molecular complexes and shed light onto Aha1's interconnections with Hsp90-regulated biological functions. Flag-tagged Aha1 was over-expressed in HeLa cells and isolated by anti-Flag affinity pull downs, followed by trypsin digestion and identification co-adsorbing proteins by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). A probability-based identification of Aha1 PPIs was generated from the LC-MS/MS analysis by using a relative quantification strategy, spectral counting (SC). By comparing the SC-based protein levels between Aha1 pull-down samples and negative controls, 164 Aha1-interacting proteins were identified that were quantitatively enriched in the pull-down samples over the controls. The identified Aha1-interacting proteins are involved in a wide number of intracellular bioprocesses, including DNA maintenance, chromatin structure, RNA processing, translation, nucleocytoplasmic and vesicle transport, among others. The interactions of 33 of the identified proteins with Aha1 were further confirmed by Western blotting, demonstrating the reliability of our affinity-purification-coupled quantitative SC-MS strategy. Our proteomic data suggests that Aha1 may participate in diverse biological pathways to facilitate Hsp90 chaperone functions in response to stress.
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Affiliation(s)
- Liang Sun
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Steven D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Robert L Matts
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
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35
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“Three sources and three component parts” of free oligosaccharides. UKRAINIAN BIOCHEMICAL JOURNAL 2014; 86:5-17. [DOI: 10.15407/ubj86.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Tannous A, Patel N, Tamura T, Hebert DN. Reglucosylation by UDP-glucose:glycoprotein glucosyltransferase 1 delays glycoprotein secretion but not degradation. Mol Biol Cell 2014; 26:390-405. [PMID: 25428988 PMCID: PMC4310732 DOI: 10.1091/mbc.e14-08-1254] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
UDP-glucose:glycoprotein glucosyltransferase 1 (UGT1) is a central quality control gatekeeper in the mammalian endoplasmic reticulum (ER). The reglucosylation of glycoproteins supports their rebinding to the carbohydrate-binding ER molecular chaperones calnexin and calreticulin. A cell-based reglucosylation assay was used to investigate the role of UGT1 in ER protein surveillance or the quality control process. UGT1 was found to modify wild-type proteins or proteins that are expected to eventually traffic out of the ER through the secretory pathway. Trapping of reglucosylated wild-type substrates in their monoglucosylated state delayed their secretion. Whereas terminally misfolded substrates or off-pathway proteins were most efficiently reglucosylated by UGT1, the trapping of these mutant substrates in their reglucosylated or monoglucosylated state did not delay their degradation by the ER-associated degradation pathway. This indicated that monoglucosylated mutant proteins were actively extracted from the calnexin/calreticulin binding-reglucosylation cycle for degradation. Therefore trapping proteins in their monoglucosylated state was sufficient to delay their exit to the Golgi but had no effect on their rate of degradation, suggesting that the degradation selection process progressed in a dominant manner that was independent of reglucosylation and the glucose-containing A-branch on the substrate glycans.
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Affiliation(s)
- Abla Tannous
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Nishant Patel
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Taku Tamura
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Daniel N Hebert
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
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37
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Benyair R, Ogen-Shtern N, Mazkereth N, Shai B, Ehrlich M, Lederkremer GZ. Mammalian ER mannosidase I resides in quality control vesicles, where it encounters its glycoprotein substrates. Mol Biol Cell 2014; 26:172-84. [PMID: 25411339 PMCID: PMC4294666 DOI: 10.1091/mbc.e14-06-1152] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
ER mannosidase I (ERManI) was found recently in the Golgi. This result is found to arise artificially from membrane disturbance in immunofluorescence methods. ERManI is located in novel vesicles to which substrates traffic and that converge at the ER-derived quality control compartment under ER stress. Endoplasmic reticulum α1,2 mannosidase I (ERManI), a central component of ER quality control and ER-associated degradation (ERAD), acts as a timer enzyme, modifying N-linked sugar chains of glycoproteins with time. This process halts glycoprotein folding attempts when necessary and targets terminally misfolded glycoproteins to ERAD. Despite the importance of ERManI in maintenance of glycoprotein quality control, fundamental questions regarding this enzyme remain controversial. One such question is the subcellular localization of ERManI, which has been suggested to localize to the ER membrane, the ER-derived quality control compartment (ERQC), and, surprisingly, recently to the Golgi apparatus. To try to clarify this controversy, we applied a series of approaches that indicate that ERManI is located, at the steady state, in quality control vesicles (QCVs) to which ERAD substrates are transported and in which they interact with the enzyme. Both endogenous and exogenously expressed ERManI migrate at an ER-like density on iodixanol gradients, suggesting that the QCVs are derived from the ER. The QCVs are highly mobile, displaying dynamics that are dependent on microtubules and COP-II but not on COP-I vesicle machinery. Under ER stress conditions, the QCVs converge in a juxtanuclear region, at the ERQC, as previously reported. Our results also suggest that ERManI is turned over by an active autophagic process. Of importance, we found that membrane disturbance, as is common in immunofluorescence methods, leads to an artificial appearance of ERManI in a Golgi pattern.
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Affiliation(s)
- Ron Benyair
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Navit Ogen-Shtern
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Niv Mazkereth
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ben Shai
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gerardo Z Lederkremer
- Department of Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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38
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Hebert DN, Lamriben L, Powers ET, Kelly JW. The intrinsic and extrinsic effects of N-linked glycans on glycoproteostasis. Nat Chem Biol 2014; 10:902-10. [PMID: 25325701 PMCID: PMC4232232 DOI: 10.1038/nchembio.1651] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/28/2014] [Indexed: 01/29/2023]
Abstract
Proteins that traffic through the eukaryotic secretory pathway are commonly modified with N-linked carbohydrates. These bulky amphipathic modifications at asparagines intrinsically enhance solubility and folding energetics through carbohydrate-protein interactions. N-linked glycans can also extrinsically enhance glycoprotein folding by using the glycoprotein homeostasis or 'glycoproteostasis' network, which comprises numerous glycan binding and/or modification enzymes or proteins that synthesize, transfer, sculpt and use N-linked glycans to direct folding and trafficking versus degradation and trafficking of nascent N-glycoproteins through the cellular secretory pathway. If protein maturation is perturbed by misfolding, aggregation or both, stress pathways are often activated that result in transcriptional remodeling of the secretory pathway in an attempt to alleviate the insult (or insults). The inability to achieve glycoproteostasis is linked to several pathologies, including amyloidoses, cystic fibrosis and lysosomal storage diseases. Recent progress on genetic and pharmacologic adaptation of the glycoproteostasis network provides hope that drugs of this mechanistic class can be developed for these maladies in the near future.
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Affiliation(s)
- Daniel N. Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003
| | - Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003
| | - Evan T. Powers
- Departments of Chemistry and Molecular and Experimental Medicine and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Jeffery W. Kelly
- Departments of Chemistry and Molecular and Experimental Medicine and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
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Enns GM, Shashi V, Bainbridge M, Gambello MJ, Zahir FR, Bast T, Crimian R, Schoch K, Platt J, Cox R, Bernstein JA, Scavina M, Walter RS, Bibb A, Jones M, Hegde M, Graham BH, Need AC, Oviedo A, Schaaf CP, Boyle S, Butte AJ, Chen R, Chen R, Clark MJ, Haraksingh R, Cowan TM, He P, Langlois S, Zoghbi HY, Snyder M, Gibbs RA, Freeze HH, Goldstein DB. Mutations in NGLY1 cause an inherited disorder of the endoplasmic reticulum-associated degradation pathway. Genet Med 2014; 16:751-8. [PMID: 24651605 DOI: 10.1038/gim.2014.22] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/09/2014] [Indexed: 12/13/2022] Open
Abstract
PURPOSE The endoplasmic reticulum-associated degradation pathway is responsible for the translocation of misfolded proteins across the endoplasmic reticulum membrane into the cytosol for subsequent degradation by the proteasome. To define the phenotype associated with a novel inherited disorder of cytosolic endoplasmic reticulum-associated degradation pathway dysfunction, we studied a series of eight patients with deficiency of N-glycanase 1. METHODS Whole-genome, whole-exome, or standard Sanger sequencing techniques were employed. Retrospective chart reviews were performed in order to obtain clinical data. RESULTS All patients had global developmental delay, a movement disorder, and hypotonia. Other common findings included hypolacrima or alacrima (7/8), elevated liver transaminases (6/7), microcephaly (6/8), diminished reflexes (6/8), hepatocyte cytoplasmic storage material or vacuolization (5/6), and seizures (4/8). The nonsense mutation c.1201A>T (p.R401X) was the most common deleterious allele. CONCLUSION NGLY1 deficiency is a novel autosomal recessive disorder of the endoplasmic reticulum-associated degradation pathway associated with neurological dysfunction, abnormal tear production, and liver disease. The majority of patients detected to date carry a specific nonsense mutation that appears to be associated with severe disease. The phenotypic spectrum is likely to enlarge as cases with a broader range of mutations are detected.
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Affiliation(s)
- Gregory M Enns
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Vandana Shashi
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Matthew Bainbridge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Michael J Gambello
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Farah R Zahir
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Rebecca Crimian
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Kelly Schoch
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Julia Platt
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Rachel Cox
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Jonathan A Bernstein
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Mena Scavina
- Division of Pediatric Neurology, Department of Pediatrics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - Rhonda S Walter
- Division of Developmental Medicine, Department of Pediatrics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - Audrey Bibb
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Melanie Jones
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Madhuri Hegde
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Anna C Need
- Department of Medicine, Imperial College, London, UK
| | - Angelica Oviedo
- Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christian P Schaaf
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, USA
| | - Sean Boyle
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Atul J Butte
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Rui Chen
- Department of Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Rong Chen
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Michael J Clark
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Rajini Haraksingh
- Department of Genetics, Stanford University, Stanford, California, USA
| | | | - Tina M Cowan
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Ping He
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Sylvie Langlois
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Huda Y Zoghbi
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, USA [3] Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Michael Snyder
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Richard A Gibbs
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Hudson H Freeze
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - David B Goldstein
- 1] Center for Human Genome Variation and Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA [2] Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
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Iannotti MJ, Figard L, Sokac AM, Sifers RN. A Golgi-localized mannosidase (MAN1B1) plays a non-enzymatic gatekeeper role in protein biosynthetic quality control. J Biol Chem 2014; 289:11844-11858. [PMID: 24627495 DOI: 10.1074/jbc.m114.552091] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Conformation-based disorders are manifested at the level of protein structure, necessitating an accurate understanding of how misfolded proteins are processed by the cellular proteostasis network. Asparagine-linked glycosylation plays important roles for protein quality control within the secretory pathway. The suspected role for the MAN1B1 gene product MAN1B1, also known as ER mannosidase I, is to function within the ER similar to the yeast ortholog Mns1p, which removes a terminal mannose unit to initiate a glycan-based ER-associated degradation (ERAD) signal. However, we recently discovered that MAN1B1 localizes to the Golgi complex in human cells and uncovered its participation in ERAD substrate retention, retrieval to the ER, and subsequent degradation from this organelle. The objective of the current study was to further characterize the contribution of MAN1B1 as part of a Golgi-based quality control network. Multiple lines of experimental evidence support a model in which neither the mannosidase activity nor catalytic domain is essential for the retention or degradation of the misfolded ERAD substrate Null Hong Kong. Instead, a highly conserved, vertebrate-specific non-enzymatic decapeptide sequence in the luminal stem domain plays a significant role in controlling the fate of overexpressed Null Hong Kong. Together, these findings define a new functional paradigm in which Golgi-localized MAN1B1 can play a mannosidase-independent gatekeeper role in the proteostasis network of higher eukaryotes.
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Affiliation(s)
- Michael J Iannotti
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030
| | - Lauren Figard
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Anna M Sokac
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Richard N Sifers
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
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Aikawa JI, Takeda Y, Matsuo I, Ito Y. Trimming of glucosylated N-glycans by human ER α1,2-mannosidase I. ACTA ACUST UNITED AC 2014; 155:375-84. [DOI: 10.1093/jb/mvu008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Pan S, Cheng X, Chen H, Castro PD, Ittmann MM, Hutson AW, Zapata SK, Sifers RN. ERManI is a target of miR-125b and promotes transformation phenotypes in hepatocellular carcinoma (HCC). PLoS One 2013; 8:e72829. [PMID: 23940818 PMCID: PMC3733964 DOI: 10.1371/journal.pone.0072829] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 07/14/2013] [Indexed: 02/07/2023] Open
Abstract
The MAN1B1 gene product, designated ER alpha-1, 2-mannosidase (ERManI), is an enzyme localized in the Golgi complex of mammalian cells. By functioning as a "gate keeper" to prevent the inappropriate secretion of misfolded glycoproteins, it plays a critical role in maintaining protein homeostasis in the mammalian secretory pathway. In the present study, we identified that a conserved motif within the 3'UTR of ERManI is a target of miR-125b, a microRNA frequently down-regulated in numerous types of cancers, including hepatocellular carcinoma (HCC). As predicted, the expression of ERManI is significantly elevated in HCC, as measured by immunohistochemistry in a liver spectrum tissue microarray. Additional analyses using several hepatoma cell lines demonstrated that the elevated ERManI inversely correlates with a diminished intracellular concentration of miR-125b. Moreover, functional studies indicated that RNAi-mediated knock-down of endogenous ERManI was sufficient to inhibit proliferation, migration, and invasion of hepatoma cells. These phenotypical changes occurred in the absence of alterations in global glycoprotein secretion or ER-stress status. Together, these results revealed a novel post-transcriptional regulatory mechanism for ERManI and implied that this molecule contributes to the regulation of carcinogenesis in HCC independent of its function in glycoprotein quality control.
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Affiliation(s)
- Shujuan Pan
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xiaoyun Cheng
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Lymphoma & Myeloma, University of Texas-M D Anderson Cancer Center, Houston, Texas, United States of America
| | - Hongan Chen
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
- Participant in the Baylor College of Medicine Summer Medical and Research Training Program, Baylor College of Medicine, Houston, Texas, United States of America
| | - Patricia D. Castro
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael M. Ittmann
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anne W. Hutson
- Department of Pediatrics-Gastroenterology, Hepatology & Nutrition, Baylor College of Medicine, Houston, Texas, United States of America
| | - Susan K. Zapata
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard N. Sifers
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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