1
|
Albers MD, Tiemann B, Kaynert JT, Pich A, Bakker H. Conserved cysteines prevent C-mannosylation of mucin Cys domains. FEBS J 2024; 291:3539-3552. [PMID: 38708720 DOI: 10.1111/febs.17152] [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: 11/06/2023] [Revised: 02/15/2024] [Accepted: 04/23/2024] [Indexed: 05/07/2024]
Abstract
Mucins are major components of the mucus. Besides the highly O-glycosylated tandem repeat domains, mucins contain Cys domains (CysDs). CysDs contain conserved disulfide-forming cysteine residues as well as a WxxW motif. Since this is the consensus sequence for tryptophan C-mannosylation, mucin CysDs have been suggested to be targets for C-mannosyltransferases, but this has never been directly shown. Here, we recombinantly expressed human mucin CysDs in Chinese hamster ovary (CHO) cells and analyzed the C-mannosylation status. Mass spectrometric analysis revealed that the putative C-mannose site is not or only barely C-mannosylated. However, mutation of the adjacent cysteine residues enabled C-mannosylation to occur. In contrast to mucin CysDs, the homologous CysD of human cartilage intermediate layer protein 1 (CILP1) lacks these cysteine residues preceding the WxxW motif. We show that CILP1 CysD is C-mannosylated, but introducing a cysteine at the -2 position causes this modification to be lost. We thus conclude that the presence of cysteine residues prevents the modification of the WxxW motif in CysDs.
Collapse
Affiliation(s)
| | - Birgit Tiemann
- Institute of Clinical Biochemistry, Hannover Medical School, Germany
| | | | - Andreas Pich
- Research Core Unit Proteomics and Institute of Toxicology, Hannover Medical School, Germany
| | - Hans Bakker
- Institute of Clinical Biochemistry, Hannover Medical School, Germany
| |
Collapse
|
2
|
Couto PM, Guardia CMA, Couto FL, Labriola CA, Labanda MS, Caramelo JJ. Acceptors stability modulates the efficiency of post-translational protein N-glycosylation. FASEB J 2024; 38:e23782. [PMID: 38934375 DOI: 10.1096/fj.202302267r] [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: 11/03/2023] [Revised: 05/31/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
N-glycosylation is the most common protein modification in the eukaryotic secretory pathway. It involves the attachment a high mannose glycan to Asn residues in the context of Asn-X-Ser/Thr/Cys, a motif known as N-glycosylation sequon. This process is mediated by STT3A and STT3B, the catalytic subunits of the oligosaccharyltransferase complexes. STT3A forms part of complexes associated with the SEC61 translocon and functions co-translationally. Vacant sequons have another opportunity for glycosylation by complexes carrying STT3B. Local sequence information plays an important role in determining N-glycosylation efficiency, but non-local factors can also have a significant impact. For instance, certain proteins associated with human genetic diseases exhibit abnormal N-glycosylation levels despite having wild-type acceptor sites. Here, we investigated the effect of protein stability on this process. To this end, we generated a family of 40 N-glycan acceptors based on superfolder GFP, and we measured their efficiency in HEK293 cells and in two derived cell lines lacking STT3B or STT3A. Sequon occupancy was highly dependent on protein stability, improving as the thermodynamic stability of the acceptor proteins decreases. This effect is mainly due to the activity of the STT3B-based OST complex. These findings can be integrated into a simple kinetic model that distinguishes local information within sequons from global information of the acceptor proteins.
Collapse
Affiliation(s)
- Paula M Couto
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Buenos Aires, Argentina
| | - Carlos M A Guardia
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Facundo L Couto
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Buenos Aires, Argentina
| | - Carlos A Labriola
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Buenos Aires, Argentina
| | - María S Labanda
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Buenos Aires, Argentina
| | - Julio J Caramelo
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Buenos Aires, Argentina
| |
Collapse
|
3
|
Lampson BL, Ramίrez AS, Baro M, He L, Hegde M, Koduri V, Pfaff JL, Hanna RE, Kowal J, Shirole NH, He Y, Doench JG, Contessa JN, Locher KP, Kaelin WG. Positive selection CRISPR screens reveal a druggable pocket in an oligosaccharyltransferase required for inflammatory signaling to NF-κB. Cell 2024; 187:2209-2223.e16. [PMID: 38670073 PMCID: PMC11149550 DOI: 10.1016/j.cell.2024.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/29/2023] [Accepted: 03/18/2024] [Indexed: 04/28/2024]
Abstract
Nuclear factor κB (NF-κB) plays roles in various diseases. Many inflammatory signals, such as circulating lipopolysaccharides (LPSs), activate NF-κB via specific receptors. Using whole-genome CRISPR-Cas9 screens of LPS-treated cells that express an NF-κB-driven suicide gene, we discovered that the LPS receptor Toll-like receptor 4 (TLR4) is specifically dependent on the oligosaccharyltransferase complex OST-A for N-glycosylation and cell-surface localization. The tool compound NGI-1 inhibits OST complexes in vivo, but the underlying molecular mechanism remained unknown. We did a CRISPR base-editor screen for NGI-1-resistant variants of STT3A, the catalytic subunit of OST-A. These variants, in conjunction with cryoelectron microscopy studies, revealed that NGI-1 binds the catalytic site of STT3A, where it traps a molecule of the donor substrate dolichyl-PP-GlcNAc2-Man9-Glc3, suggesting an uncompetitive inhibition mechanism. Our results provide a rationale for and an initial step toward the development of STT3A-specific inhibitors and illustrate the power of contemporaneous base-editor and structural studies to define drug mechanism of action.
Collapse
Affiliation(s)
- Benjamin L Lampson
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
| | - Ana S Ramίrez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Marta Baro
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Lixia He
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
| | - Mudra Hegde
- Genetic Perturbation Platform, Broad Institute, Cambridge, MA 02142, USA
| | - Vidyasagar Koduri
- Division of Hematology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02215, USA
| | - Jamie L Pfaff
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
| | - Ruth E Hanna
- Genetic Perturbation Platform, Broad Institute, Cambridge, MA 02142, USA
| | - Julia Kowal
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Nitin H Shirole
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
| | - Yanfeng He
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
| | - John G Doench
- Genetic Perturbation Platform, Broad Institute, Cambridge, MA 02142, USA
| | - Joseph N Contessa
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland.
| | - William G Kaelin
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA.
| |
Collapse
|
4
|
Pasala C, Sharma S, Roychowdhury T, Moroni E, Colombo G, Chiosis G. N-Glycosylation as a Modulator of Protein Conformation and Assembly in Disease. Biomolecules 2024; 14:282. [PMID: 38540703 PMCID: PMC10968129 DOI: 10.3390/biom14030282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 05/01/2024] Open
Abstract
Glycosylation, a prevalent post-translational modification, plays a pivotal role in regulating intricate cellular processes by covalently attaching glycans to macromolecules. Dysregulated glycosylation is linked to a spectrum of diseases, encompassing cancer, neurodegenerative disorders, congenital disorders, infections, and inflammation. This review delves into the intricate interplay between glycosylation and protein conformation, with a specific focus on the profound impact of N-glycans on the selection of distinct protein conformations characterized by distinct interactomes-namely, protein assemblies-under normal and pathological conditions across various diseases. We begin by examining the spike protein of the SARS virus, illustrating how N-glycans regulate the infectivity of pathogenic agents. Subsequently, we utilize the prion protein and the chaperone glucose-regulated protein 94 as examples, exploring instances where N-glycosylation transforms physiological protein structures into disease-associated forms. Unraveling these connections provides valuable insights into potential therapeutic avenues and a deeper comprehension of the molecular intricacies that underlie disease conditions. This exploration of glycosylation's influence on protein conformation effectively bridges the gap between the glycome and disease, offering a comprehensive perspective on the therapeutic implications of targeting conformational mutants and their pathologic assemblies in various diseases. The goal is to unravel the nuances of these post-translational modifications, shedding light on how they contribute to the intricate interplay between protein conformation, assembly, and disease.
Collapse
Affiliation(s)
- Chiranjeevi Pasala
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (C.P.); (S.S.); (T.R.)
| | - Sahil Sharma
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (C.P.); (S.S.); (T.R.)
| | - Tanaya Roychowdhury
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (C.P.); (S.S.); (T.R.)
| | - Elisabetta Moroni
- The Institute of Chemical Sciences and Technologies (SCITEC), Italian National Research Council (CNR), 20131 Milano, Italy; (E.M.); (G.C.)
| | - Giorgio Colombo
- The Institute of Chemical Sciences and Technologies (SCITEC), Italian National Research Council (CNR), 20131 Milano, Italy; (E.M.); (G.C.)
- Department of Chemistry, University of Pavia, 27100 Pavia, Italy
| | - Gabriela Chiosis
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (C.P.); (S.S.); (T.R.)
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| |
Collapse
|
5
|
Duran-Romaña R, Houben B, De Vleeschouwer M, Louros N, Wilson MP, Matthijs G, Schymkowitz J, Rousseau F. N-glycosylation as a eukaryotic protective mechanism against protein aggregation. SCIENCE ADVANCES 2024; 10:eadk8173. [PMID: 38295165 PMCID: PMC10830103 DOI: 10.1126/sciadv.adk8173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
The tendency for proteins to form aggregates is an inherent part of every proteome and arises from the self-assembly of short protein segments called aggregation-prone regions (APRs). While posttranslational modifications (PTMs) have been implicated in modulating protein aggregation, their direct role in APRs remains poorly understood. In this study, we used a combination of proteome-wide computational analyses and biophysical techniques to investigate the potential involvement of PTMs in aggregation regulation. Our findings reveal that while most PTM types are disfavored near APRs, N-glycosylation is enriched and evolutionarily selected, especially in proteins prone to misfolding. Experimentally, we show that N-glycosylation inhibits the aggregation of peptides in vitro through steric hindrance. Moreover, mining existing proteomics data, we find that the loss of N-glycans at the flanks of APRs leads to specific protein aggregation in Neuro2a cells. Our findings indicate that, among its many molecular functions, N-glycosylation directly prevents protein aggregation in higher eukaryotes.
Collapse
Affiliation(s)
- Ramon Duran-Romaña
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Bert Houben
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Matthias De Vleeschouwer
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Nikolaos Louros
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Matthew P. Wilson
- Laboratory for Molecular Diagnosis, Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Gert Matthijs
- Laboratory for Molecular Diagnosis, Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Joost Schymkowitz
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| |
Collapse
|
6
|
Ramírez AS, Locher KP. Structural and mechanistic studies of the N-glycosylation machinery: from lipid-linked oligosaccharide biosynthesis to glycan transfer. Glycobiology 2023; 33:861-872. [PMID: 37399117 PMCID: PMC10859629 DOI: 10.1093/glycob/cwad053] [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: 05/29/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023] Open
Abstract
N-linked protein glycosylation is a post-translational modification that exists in all domains of life. It involves two consecutive steps: (i) biosynthesis of a lipid-linked oligosaccharide (LLO), and (ii) glycan transfer from the LLO to asparagine residues in secretory proteins, which is catalyzed by the integral membrane enzyme oligosaccharyltransferase (OST). In the last decade, structural and functional studies of the N-glycosylation machinery have increased our mechanistic understanding of the pathway. The structures of bacterial and eukaryotic glycosyltransferases involved in LLO elongation provided an insight into the mechanism of LLO biosynthesis, whereas structures of OST enzymes revealed the molecular basis of sequon recognition and catalysis. In this review, we will discuss approaches used and insight obtained from these studies with a special emphasis on the design and preparation of substrate analogs.
Collapse
Affiliation(s)
- Ana S Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| |
Collapse
|
7
|
Guay KP, Ke H, Canniff NP, George GT, Eyles SJ, Mariappan M, Contessa JN, Gershenson A, Gierasch LM, Hebert DN. ER chaperones use a protein folding and quality control glyco-code. Mol Cell 2023; 83:4524-4537.e5. [PMID: 38052210 PMCID: PMC10790639 DOI: 10.1016/j.molcel.2023.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/18/2023] [Accepted: 11/07/2023] [Indexed: 12/07/2023]
Abstract
N-glycans act as quality control tags by recruiting lectin chaperones to assist protein maturation in the endoplasmic reticulum. The location and composition of N-glycans (glyco-code) are key to the chaperone-selection process. Serpins, a class of serine protease inhibitors, fold non-sequentially to achieve metastable active states. Here, the role of the glyco-code in assuring successful maturation and quality control of two human serpins, alpha-1 antitrypsin (AAT) and antithrombin III (ATIII), is described. We find that AAT, which has glycans near its N terminus, is assisted by early lectin chaperone binding. In contrast, ATIII, which has more C-terminal glycans, is initially helped by BiP and then later by lectin chaperones mediated by UGGT reglucosylation. UGGT action is increased for misfolding-prone disease variants, and these clients are preferentially glucosylated on their most C-terminal glycan. Our study illustrates how serpins utilize N-glycan presence, position, and composition to direct their proper folding, quality control, and trafficking.
Collapse
Affiliation(s)
- Kevin P Guay
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Haiping Ke
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Nathan P Canniff
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Gracie T George
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Stephen J Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Institute for Applied Life Sciences, Mass Spectrometry Center, University of Massachusetts Amherst, Amherst, MA, USA
| | - Malaiyalam Mariappan
- Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, West Haven, CT, USA
| | - Joseph N Contessa
- Departments of Therapeutic Radiology and Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Lila M Gierasch
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Department of Chemistry, University of Massachusetts Amherst, Amherst, MA, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA.
| |
Collapse
|
8
|
Scheich S, Chen J, Liu J, Schnütgen F, Enssle JC, Ceribelli M, Thomas CJ, Choi J, Morris V, Hsiao T, Nguyen H, Wang B, Bolomsky A, Phelan JD, Corcoran S, Urlaub H, Young RM, Häupl B, Wright GW, Huang DW, Ji Y, Yu X, Xu W, Yang Y, Zhao H, Muppidi J, Pan KT, Oellerich T, Staudt LM. Targeting N-linked Glycosylation for the Therapy of Aggressive Lymphomas. Cancer Discov 2023; 13:1862-1883. [PMID: 37141112 PMCID: PMC10524254 DOI: 10.1158/2159-8290.cd-22-1401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/21/2023] [Accepted: 05/02/2023] [Indexed: 05/05/2023]
Abstract
Diffuse large B-cell lymphoma (DLBCL) can be subdivided into the activated B-cell (ABC) and germinal center B cell-like (GCB) subtypes. Self-antigen engagement of B-cell receptors (BCR) in ABC tumors induces their clustering, thereby initiating chronic active signaling and activation of NF-κB and PI3 kinase. Constitutive BCR signaling is essential in some GCB tumors but primarily activates PI3 kinase. We devised genome-wide CRISPR-Cas9 screens to identify regulators of IRF4, a direct transcriptional target of NF-κB and an indicator of proximal BCR signaling in ABC DLBCL. Unexpectedly, inactivation of N-linked protein glycosylation by the oligosaccharyltransferase-B (OST-B) complex reduced IRF4 expression. OST-B inhibition of BCR glycosylation reduced BCR clustering and internalization while promoting its association with CD22, which attenuated PI3 kinase and NF-κB activation. By directly interfering with proximal BCR signaling, OST-B inactivation killed models of ABC and GCB DLBCL, supporting the development of selective OST-B inhibitors for the treatment of these aggressive cancers. SIGNIFICANCE DLBCL depends on constitutive BCR activation and signaling. There are currently no therapeutics that target the BCR directly and attenuate its pathologic signaling. Here, we unraveled a therapeutically exploitable, OST-B-dependent glycosylation pathway that drives BCR organization and proximal BCR signaling. This article is highlighted in the In This Issue feature, p. 1749.
Collapse
Affiliation(s)
- Sebastian Scheich
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Jiamin Liu
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Frank Schnütgen
- Department of Medicine, Hematology/Oncology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt/Main, Germany
| | - Julius C. Enssle
- Department of Medicine, Hematology/Oncology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Michele Ceribelli
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Craig J. Thomas
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Jaewoo Choi
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Vivian Morris
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Johns Hopkins University, Department of Biology, Baltimore, MD, 21218, USA
| | - Tony Hsiao
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hang Nguyen
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Boya Wang
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arnold Bolomsky
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James D. Phelan
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sean Corcoran
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Ryan M. Young
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Björn Häupl
- Department of Medicine, Hematology/Oncology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt/Main, Germany
| | - George W. Wright
- Biometric Research Branch, Division of Cancer Diagnosis and Treatment, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Da Wei Huang
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yanlong Ji
- Department of Medicine, Hematology/Oncology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
- Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt/Main, Germany
| | - Xin Yu
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Weihong Xu
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yandan Yang
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hong Zhao
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jagan Muppidi
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kuan-Ting Pan
- Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt/Main, Germany
| | - Thomas Oellerich
- Department of Medicine, Hematology/Oncology, University Hospital Frankfurt, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt/Main, Germany
| | - Louis M. Staudt
- Lymphoid Malignancies Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
9
|
Vlad DB, Dumitrascu DI, Dumitrascu AL. Golgi's Role in the Development of Possible New Therapies in Cancer. Cells 2023; 12:1499. [PMID: 37296620 PMCID: PMC10252985 DOI: 10.3390/cells12111499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
The Golgi apparatus is an important organelle found in most eukaryotic cells. It plays a vital role in the processing and sorting of proteins, lipids and other cellular components for delivery to their appropriate destinations within the cell or for secretion outside of the cell. The Golgi complex also plays a role in the regulation of protein trafficking, secretion and post-translational modifications, which are significant in the development and progression of cancer. Abnormalities in this organelle have been observed in various types of cancer, although research into chemotherapies that target the Golgi apparatus is still in its early stages. There are a few promising approaches that are being investigated: (1) Targeting the stimulator of interferon genes protein: The STING pathway senses cytosolic DNA and activates several signaling events. It is regulated by numerous post-translational modifications and relies heavily on vesicular trafficking. Based on some observations which state that a decreased STING expression is present in some cancer cells, agonists for the STING pathway have been developed and are currently being tested in clinical trials, showing encouraging results. (2) Targeting glycosylation: Altered glycosylation, which refers to changes in the carbohydrate molecules that are attached to proteins and lipids in cells, is a common feature of cancer cells, and there are several methods that thwart this process. For example, some inhibitors of glycosylation enzymes have been shown to reduce tumor growth and metastasis in preclinical models of cancer. (3) Targeting Golgi trafficking: The Golgi apparatus is responsible for the sorting and trafficking of proteins within the cell, and disrupting this process may be a potential therapeutic approach for cancer. The unconventional protein secretion is a process that occurs in response to stress and does not require the involvement of the Golgi organelles. P53 is the most frequently altered gene in cancer, dysregulating the normal cellular response to DNA damage. The mutant p53 drives indirectly the upregulation of the Golgi reassembly-stacking protein 55kDa (GRASP55). Through the inhibition of this protein in preclinical models, the reduction of the tumoral growth and metastatic capacity have been obtained successfully. This review supports the hypothesis that the Golgi apparatus may be the target of cytostatic treatment, considering its role in the molecular mechanisms of the neoplastic cells.
Collapse
Affiliation(s)
- Dragos-Bogdan Vlad
- Emergency Clinical Hospital of Saint Pantelimon, 021659 Bucharest, Romania;
| | - David-Ioan Dumitrascu
- Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania;
| | - Alina-Laura Dumitrascu
- Emergency Clinical Hospital of Saint Pantelimon, 021659 Bucharest, Romania;
- Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania;
| |
Collapse
|
10
|
Wang B, Wan AH, Xu Y, Zhang RX, Zhao BC, Zhao XY, Shi YC, Zhang X, Xue Y, Luo Y, Deng Y, Neely GG, Wan G, Wang QP. Identification of indocyanine green as a STT3B inhibitor against mushroom α-amanitin cytotoxicity. Nat Commun 2023; 14:2241. [PMID: 37193694 PMCID: PMC10188588 DOI: 10.1038/s41467-023-37714-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 03/21/2023] [Indexed: 05/18/2023] Open
Abstract
The "death cap", Amanita phalloides, is the world's most poisonous mushroom, responsible for 90% of mushroom-related fatalities. The most fatal component of the death cap is α-amanitin. Despite its lethal effect, the exact mechanisms of how α-amanitin poisons humans remain unclear, leading to no specific antidote available for treatment. Here we show that STT3B is required for α-amanitin toxicity and its inhibitor, indocyanine green (ICG), can be used as a specific antidote. By combining a genome-wide CRISPR screen with an in silico drug screening and in vivo functional validation, we discover that N-glycan biosynthesis pathway and its key component, STT3B, play a crucial role in α-amanitin toxicity and that ICG is a STT3B inhibitor. Furthermore, we demonstrate that ICG is effective in blocking the toxic effect of α-amanitin in cells, liver organoids, and male mice, resulting in an overall increase in animal survival. Together, by combining a genome-wide CRISPR screen for α-amanitin toxicity with an in silico drug screen and functional validation in vivo, our study highlights ICG as a STT3B inhibitor against the mushroom toxin.
Collapse
Affiliation(s)
- Bei Wang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Arabella H Wan
- Department of Pathology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, PR China
| | - Yu Xu
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Ruo-Xin Zhang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Ben-Chi Zhao
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Xin-Yuan Zhao
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yan-Chuan Shi
- Obesity and Metabolic Disease Research Group, Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia
| | - Xiaolei Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China
| | - Yongbo Xue
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yong Luo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - G Gregory Neely
- Dr. John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Guohui Wan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China.
| | - Qiao-Ping Wang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China.
| |
Collapse
|
11
|
Cui T, Ma Q, Zhang F, Chen S, Zhang C, Hao J, Liu X. Characterization of PcSTT3B as a Key Oligosaccharyltransferase Subunit Involved in N-glycosylation and Its Role in Development and Pathogenicity of Phytophthora capsici. Int J Mol Sci 2023; 24:ijms24087500. [PMID: 37108663 PMCID: PMC10141488 DOI: 10.3390/ijms24087500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/08/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Asparagine (Asn, N)-linked glycosylation is a conserved process and an essential post-translational modification that occurs on the NXT/S motif of the nascent polypeptides in endoplasmic reticulum (ER). The mechanism of N-glycosylation and biological functions of key catalytic enzymes involved in this process are rarely documented for oomycetes. In this study, an N-glycosylation inhibitor tunicamycin (TM) hampered the mycelial growth, sporangial release, and zoospore production of Phytophthora capsici, indicating that N-glycosylation was crucial for oomycete growth development. Among the key catalytic enzymes involved in N-glycosylation, the PcSTT3B gene was characterized by its functions in P. capsici. As a core subunit of the oligosaccharyltransferase (OST) complex, the staurosporine and temperature sensive 3B (STT3B) subunit were critical for the catalytic activity of OST. The PcSTT3B gene has catalytic activity and is highly conservative in P. capsici. By using a CRISPR/Cas9-mediated gene replacement system to delete the PcSTT3B gene, the transformants impaired mycelial growth, sporangial release, zoospore production, and virulence. The PcSTT3B-deleted transformants were more sensitive to an ER stress inducer TM and display low glycoprotein content in the mycelia, suggesting that PcSTT3B was associated with ER stress responses and N-glycosylation. Therefore, PcSTT3B was involved in the development, pathogenicity, and N-glycosylation of P. capsici.
Collapse
Affiliation(s)
- Tongshan Cui
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Quanhe Ma
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Fan Zhang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Shanshan Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Can Zhang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Jianjun Hao
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - Xili Liu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling 712100, China
| |
Collapse
|
12
|
Phoomak C, Rinis N, Baro M, Shrimal S, Bennett D, Shaffer SA, Lehrman M, Gilmore R, Contessa JN. Signal recognition particle receptor-β (SR-β) coordinates cotranslational N-glycosylation. SCIENCE ADVANCES 2023; 9:eade8079. [PMID: 36921042 PMCID: PMC10017033 DOI: 10.1126/sciadv.ade8079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Proteins destined for the secretory compartment of the cell are cotranslationally translocated into the endoplasmic reticulum. The majority of these proteins are N-glycosylated, a co- and posttranslational modification that ensures proper protein folding, stability, solubility, and cellular localization. Here, we show that the [Formula: see text] subunit of the signal recognition particle receptor (SR) is required for assembly of the N-glycosylation-competent translocon. We report that guanine analog chemical probes identified by high-throughput screening or mutation of the SR-[Formula: see text] guanosine triphosphate binding site cause an N-glycosylation-deficient phenotype. Neither method alters the association of SR-[Formula: see text] with SR-[Formula: see text], but both approaches reduce the association of SR-[Formula: see text] with the oligosaccharyltransferase complex. These experiments demonstrate that SR-[Formula: see text] has a previously unrecognized function coordinating endoplasmic reticulum translation with N-glycosylation.
Collapse
Affiliation(s)
- Chatchai Phoomak
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06511, USA
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Natalie Rinis
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06511, USA
| | - Marta Baro
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06511, USA
| | - Shiteshu Shrimal
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Daniel Bennett
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06511, USA
| | - Scott A. Shaffer
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Mass Spectrometry Facility, University of Massachusetts Chan Medical School, Shrewsbury, MA 01545, USA
| | - Mark Lehrman
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, 6001 Forest Park Rd., Dallas, TX 75390, USA
| | - Reid Gilmore
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Joseph N. Contessa
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06511, USA
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06511, USA
| |
Collapse
|
13
|
N-Glycan on the Non-Consensus N-X-C Glycosylation Site Impacts Activity, Stability, and Localization of the Sd a Synthase B4GALNT2. Int J Mol Sci 2023; 24:ijms24044139. [PMID: 36835549 PMCID: PMC9959560 DOI: 10.3390/ijms24044139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
The Sda carbohydrate epitope and its biosynthetic B4GALNT2 enzyme are expressed in the healthy colon and down-regulated to variable extents in colon cancer. The human B4GALNT2 gene drives the expression of a long and a short protein isoform (LF-B4GALNT2 and SF-B4GALNT2) sharing identical transmembrane and luminal domains. Both isoforms are trans-Golgi proteins and the LF-B4GALNT2 also localizes to post-Golgi vesicles thanks to its extended cytoplasmic tail. Control mechanisms underpinning Sda and B4GALNT2 expression in the gastrointestinal tract are complex and not fully understood. This study reveals the existence of two unusual N-glycosylation sites in B4GALNT2 luminal domain. The first atypical N-X-C site is evolutionarily conserved and occupied by a complex-type N-glycan. We explored the influence of this N-glycan using site-directed mutagenesis and showed that each mutant had a slightly decreased expression level, impaired stability, and reduced enzyme activity. Furthermore, we observed that the mutant SF-B4GALNT2 was partially mislocalized in the endoplasmic reticulum, whereas the mutant LF-B4GALNT2 was still localized in the Golgi and post-Golgi vesicles. Lastly, we showed that the formation of homodimers was drastically impaired in the two mutated isoforms. An AlphaFold2 model of the LF-B4GALNT2 dimer with an N-glycan on each monomer corroborated these findings and suggested that N-glycosylation of each B4GALNT2 isoform controlled their biological activity.
Collapse
|
14
|
Munteanu CVA, Chirițoiu GN, Petrescu AJ, Petrescu ȘM. Defining the altered glycoproteomic space of the early secretory pathway by class I mannosidase pharmacological inhibition. Front Mol Biosci 2023; 9:1064868. [PMID: 36699698 PMCID: PMC9869281 DOI: 10.3389/fmolb.2022.1064868] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023] Open
Abstract
N-glycosylation is a key process for various biological functions like protein folding, maturation and sorting for the conventional secretory compartment, cell-cell communication and immune response. This is usually accomplished by a complex system of mannosidases in which those from class I have an outstanding role, commonly involved in the early protein sorting associated to the Endoplasmic Reticulum (ER) in the N-glycan dependent quality control (ERQC) and ER-associated degradation (ERAD). Although these are vital processes in maintaining cellular homeostasis, large-scale analysis studies for this pool of molecules, further denoted as proteins from the early secretory pathway (ESP), were limited addressed. Here, using a custom workflow employing a combination of glycomics and deglycoproteomics analyses, using lectin affinity and selective Endoglycosidase H (Endo H) digestion, we scrutinize the steady-state oligomannosidic glycoprotein load and delineate ESP fraction in melanoma cells. All of these were assessed by applying our workflow for glycosite relative quantification of both the peptide chain and carbohydrate structure in cells with inhibited activity of class I mannosidases after kifunensine treatment. We found that most of the ESP are transient clients involved in cell communication via extracellular matrix, particularly integrin-mediated communication which adopt Man9 N-glycans in kifunensine-treated cells. Moreover, our results reveal that core-fucosylation is decreased subsequent inhibition of class I mannosidases and this could be explained by a general lower protein level of FUT8, the enzyme responsible for fucosylation. By comparing our data with results obtained following downregulation of a key mannosidase in misfolded protein degradation, we mapped both novel and previously suggested endogenous substrate candidates like PCDH2, HLA-B, LAMB2 or members of the integrin family of proteins such as ITGA1 and ITGA4, thus validating the findings obtained using our workflow regarding accumulation and characterization of ESP transitory members following mannosidase class I inhibition. This workflow and the associated dataset not only allowed us to investigate the oligomannosidic glycoprotein fraction but also to delineate differences mediated at glycosite-level upon kifunensine treatment and outline the potential associated cellular responses.
Collapse
Affiliation(s)
- Cristian V A Munteanu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry, Bucharest, Romania
| | - Gabriela N Chirițoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Bucharest, Romania
| | - Andrei-Jose Petrescu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry, Bucharest, Romania
| | - Ștefana M Petrescu
- Department of Molecular Cell Biology, Institute of Biochemistry, Bucharest, Romania
| |
Collapse
|
15
|
Williams RV, Huang C, McDermott C, Ahmed T, Columbus L, Moremen KW, Prestegard JH, Amster IJ. Site-to-site cross-talk in OST-B glycosylation of hCEACAM1-IgV. Proc Natl Acad Sci U S A 2022; 119:e2202992119. [PMID: 36251991 PMCID: PMC9618145 DOI: 10.1073/pnas.2202992119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 09/21/2022] [Indexed: 11/18/2022] Open
Abstract
N-glycosylation is a common posttranslational modification of secreted proteins in eukaryotes. This modification targets asparagine residues within the consensus sequence, N-X-S/T. While this sequence is required for glycosylation, the initial transfer of a high-mannose glycan by oligosaccharyl transferases A or B (OST-A or OST-B) can lead to incomplete occupancy at a given site. Factors that determine the extent of transfer are not well understood, and understanding them may provide insight into the function of these important enzymes. Here, we use mass spectrometry (MS) to simultaneously measure relative occupancies for three N-glycosylation sites on the N-terminal IgV domain of the recombinant glycoprotein, hCEACAM1. We demonstrate that addition is primarily by the OST-B enzyme and propose a kinetic model of OST-B N-glycosylation. Fitting the kinetic model to the MS data yields distinct rates for glycan addition at most sites and suggests a largely stochastic initial order of glycan addition. The model also suggests that glycosylation at one site influences the efficiency of subsequent modifications at the other sites, and glycosylation at the central or N-terminal site leads to dead-end products that seldom lead to full glycosylation of all three sites. Only one path of progressive glycosylation, one initiated by glycosylation at the C-terminal site, can efficiently lead to full occupancy for all three sites. Thus, the hCEACAM1 domain provides an effective model system to study site-specific recognition of glycosylation sequons by OST-B and suggests that the order and efficiency of posttranslational glycosylation is influenced by steric cross-talk between adjoining acceptor sites.
Collapse
Affiliation(s)
- Robert V. Williams
- Department of Chemistry, University of Georgia, Athens, GA 30602
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - Chin Huang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | - Connor McDermott
- Department of Chemistry, University of Virginia, Charlottesville, VA 22901
| | - Tanvir Ahmed
- Department of Chemistry, University of Georgia, Athens, GA 30602
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, VA 22901
| | - Kelley W. Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | - James H. Prestegard
- Department of Chemistry, University of Georgia, Athens, GA 30602
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | | |
Collapse
|
16
|
Substrate-driven assembly of a translocon for multipass membrane proteins. Nature 2022; 611:167-172. [PMID: 36261522 PMCID: PMC9630114 DOI: 10.1038/s41586-022-05330-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 09/07/2022] [Indexed: 11/19/2022]
Abstract
Most membrane proteins are synthesized on endoplasmic reticulum (ER)-bound ribosomes docked at the translocon, a heterogeneous ensemble of transmembrane factors operating on the nascent chain1,2. How the translocon coordinates the actions of these factors to accommodate its different substrates is not well understood. Here we define the composition, function and assembly of a translocon specialized for multipass membrane protein biogenesis3. This ‘multipass translocon’ is distinguished by three components that selectively bind the ribosome–Sec61 complex during multipass protein synthesis: the GET- and EMC-like (GEL), protein associated with translocon (PAT) and back of Sec61 (BOS) complexes. Analysis of insertion intermediates reveals how features of the nascent chain trigger multipass translocon assembly. Reconstitution studies demonstrate a role for multipass translocon components in protein topogenesis, and cells lacking these components show reduced multipass protein stability. These results establish the mechanism by which nascent multipass proteins selectively recruit the multipass translocon to facilitate their biogenesis. More broadly, they define the ER translocon as a dynamic assembly whose subunit composition adjusts co-translationally to accommodate the biosynthetic needs of its diverse range of substrates. Biochemical reconstitution and functional analysis reveal how newly synthesized multipass membrane proteins dynamically remodel the translocon to facilitate their successful biogenesis.
Collapse
|
17
|
Proteome and Glycoproteome Analyses Reveal the Protein N-Linked Glycosylation Specificity of STT3A and STT3B. Cells 2022; 11:cells11182775. [PMID: 36139350 PMCID: PMC9496733 DOI: 10.3390/cells11182775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
STT3A and STT3B are the main catalytic subunits of the oligosaccharyltransferase complex (OST-A and OST-B in mammalian cells), which primarily mediate cotranslational and post-translocational N-linked glycosylation, respectively. To determine the specificity of STT3A and STT3B, we performed proteomic and glycoproteomic analyses in the gene knock-out (KO) and wild-type HEK293 cells. In total, 3961 proteins, 4265 unique N-linked intact glycopeptides and 629 glycosites representing 349 glycoproteins were identified from all these cells. Deletion of the STT3A gene had a greater impact on the protein expression than deletion of STT3B, especially on glycoproteins. In addition, total mannosylated N-glycans were reduced and fucosylated N-glycans were increased in STT3A-KO cells, which were caused by the differential expression of glycan-related enzymes. Interestingly, hyperglycosylated proteins were identified in KO cells, and the hyperglycosylation of ENPL was caused by the endoplasmic reticulum (ER) stress due to the STT3A deletion. Furthermore, the increased expression of the ATF6 and PERK indicated that the unfolded protein response also happened in STT3A-KO cells. Overall, the specificity of STT3A and STT3B revealed that defects in the OST subunit not only broadly affect N-linked glycosylation of the protein but also affect protein expression.
Collapse
|
18
|
Bakshi T, Pham D, Kaur R, Sun B. Hidden Relationships between N-Glycosylation and Disulfide Bonds in Individual Proteins. Int J Mol Sci 2022; 23:ijms23073742. [PMID: 35409101 PMCID: PMC8998389 DOI: 10.3390/ijms23073742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/25/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
N-Glycosylation (NG) and disulfide bonds (DBs) are two prevalent co/post-translational modifications (PTMs) that are often conserved and coexist in membrane and secreted proteins involved in a large number of diseases. Both in the past and in recent times, the enzymes and chaperones regulating these PTMs have been constantly discovered to directly interact with each other or colocalize in the ER. However, beyond a few model proteins, how such cooperation affects N-glycan modification and disulfide bonding at selective sites in individual proteins is largely unknown. Here, we reviewed the literature to discover the current status in understanding the relationships between NG and DBs in individual proteins. Our results showed that more than 2700 human proteins carry both PTMs, and fewer than 2% of them have been investigated in the associations between NG and DBs. We summarized both these proteins with the reported relationships in the two PTMs and the tools used to discover the relationships. We hope that, by exposing this largely understudied field, more investigations can be encouraged to unveil the hidden relationships of NG and DBs in the majority of membranes and secreted proteins for pathophysiological understanding and biotherapeutic development.
Collapse
Affiliation(s)
- Tania Bakshi
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - David Pham
- Department of Computing Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Raminderjeet Kaur
- Faculty of Health Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Bingyun Sun
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Correspondence:
| |
Collapse
|
19
|
Lack of NKG2D in MAGT1-deficient patients is caused by hypoglycosylation. Hum Genet 2022; 141:1279-1286. [PMID: 35182234 DOI: 10.1007/s00439-021-02400-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 11/06/2021] [Indexed: 12/20/2022]
Abstract
Mutations in the X-linked gene MAGT1 cause a Congenital Disorder of Glycosylation (CDG), with two distinct clinical phenotypes: a primary immunodeficiency (XMEN disorder) versus intellectual and developmental disability. It was previously established that MAGT1 deficiency abolishes steady-state expression of the immune response protein NKG2D (encoded by KLRK1) in lymphocytes. Here, we show that the reduced steady-state levels of NKG2D are caused by hypoglycosylation of the protein and we pinpoint the exact site that is underglycosylated in MAGT1-deficient patients. Furthermore, we challenge the possibility that supplementation with magnesium restores NKG2D levels and show that the addition of this ion does not significantly improve NKG2D steady-state expression nor does it rescue the hypoglycosylation defect in CRISPR-engineered human cell lines. Moreover, magnesium supplementation of an XMEN patient did not result in restoration of NKG2D expression on the cell surface of lymphocytes. In summary, we demonstrate that in MAGT1-deficient patients, the lack of NKG2D is caused by hypoglycosylation, further elucidating the pathophysiology of XMEN/MAGT1-CDG.
Collapse
|
20
|
Peng L, Du J, Zhang R, Zhu N, Zhao H, Zhao Q, Yu Q, Li M. The Transient Receptor Potential Channel Yvc1 Deletion Recovers the Growth Defect of Calcineurin Mutant Under Endoplasmic Reticulum Stress in Candida albicans. Front Microbiol 2021; 12:752670. [PMID: 34917046 PMCID: PMC8669648 DOI: 10.3389/fmicb.2021.752670] [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] [Received: 08/03/2021] [Accepted: 10/07/2021] [Indexed: 11/24/2022] Open
Abstract
Transient receptor potential (TRP) channel Yvc1 was related with hyphal growth, oxidative stress response, and pathogenicity. Calcineurin subunit Cnb1 was activated immediately in yeasts when exposed to severe stimulation. However, the relationship between Yvc1 and Cnb1-governed calcium ions and endoplasmic reticulum (ER) stress response remains unrevealed. In this study, we found that the mutant cnb1Δ/Δ was sensitive to TN, which was related with the overexpression of membrane calcium ion channels that could increase the cytosol calcium concentration. However, the growth of the cnb1Δ/Δyvc1Δ/Δ mutant was recovered and its cell vitality was better than the cnb1Δ/Δ strain. Meanwhile, the cellular calcium concentration was decreased and its fluctuation was weakened under ER stress in the cnb1Δ/Δyvc1Δ/Δ strain. To verify the regulation role of Yvc1 in the calcium concentration, we found that the addition of CaCl2 led to the worse viability, while the growth state was relieved under the treatment of EGTA in the cnb1Δ/Δ strain. In conclusion, the deletion of YVC1 could reduce the cellular calcium and relieve the ER stress sensitivity of the cnb1Δ/Δ strain. Thereby, our findings shed a novel light on the relationship between the Yvc1-governed cellular calcium concentration and ER stress response in C. albicans.
Collapse
Affiliation(s)
- Liping Peng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiawen Du
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Runfan Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - He Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Qiang Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| |
Collapse
|
21
|
van Lith M, Pringle MA, Fleming B, Gaeta G, Im J, Gilmore R, Bulleid NJ. A cytosolic reductase pathway is required for efficient N-glycosylation of an STT3B-dependent acceptor site. J Cell Sci 2021; 134:273533. [PMID: 34734627 PMCID: PMC8645230 DOI: 10.1242/jcs.259340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/27/2021] [Indexed: 11/20/2022] Open
Abstract
N-linked glycosylation of proteins entering the secretory pathway is an essential modification required for protein stability and function. Previously, it has been shown that there is a temporal relationship between protein folding and glycosylation, which influences the occupancy of specific glycosylation sites. Here, we used an in vitro translation system that reproduces the initial stages of secretory protein translocation, folding and glycosylation under defined redox conditions. We found that the efficiency of glycosylation of hemopexin was dependent upon a robust NADPH-dependent cytosolic reductive pathway, which could be mimicked by the addition of a membrane-impermeable reducing agent. We identified a hypoglycosylated acceptor site that is adjacent to a cysteine involved in a short-range disulfide. We show that efficient glycosylation at this site is influenced by the cytosolic reductive pathway acting on both STT3A- and STT3B-dependent glycosylation. Our results provide further insight into the important role of the endoplasmic reticulum redox conditions in glycosylation site occupancy and demonstrate a link between redox conditions in the cytosol and glycosylation efficiency.
Collapse
Affiliation(s)
- Marcel van Lith
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Marie Anne Pringle
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Bethany Fleming
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Giorgia Gaeta
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK.,Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, Headington, Oxford OX3 7LD, UK
| | - Jisu Im
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK.,Cellular Protein Chemistry, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Neil J Bulleid
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| |
Collapse
|
22
|
Wilson MP, Garanto A, Pinto e Vairo F, Ng BG, Ranatunga WK, Ventouratou M, Baerenfaenger M, Huijben K, Thiel C, Ashikov A, Keldermans L, Souche E, Vuillaumier-Barrot S, Dupré T, Michelakakis H, Fiumara A, Pitt J, White SM, Lim SC, Gallacher L, Peters H, Rymen D, Witters P, Ribes A, Morales-Romero B, Rodríguez-Palmero A, Ballhausen D, de Lonlay P, Barone R, Janssen MC, Jaeken J, Freeze HH, Matthijs G, Morava E, Lefeber DJ. Active site variants in STT3A cause a dominant type I congenital disorder of glycosylation with neuromusculoskeletal findings. Am J Hum Genet 2021; 108:2130-2144. [PMID: 34653363 DOI: 10.1016/j.ajhg.2021.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/21/2021] [Indexed: 12/27/2022] Open
Abstract
Congenital disorders of glycosylation (CDGs) form a group of rare diseases characterized by hypoglycosylation. We here report the identification of 16 individuals from nine families who have either inherited or de novo heterozygous missense variants in STT3A, leading to an autosomal-dominant CDG. STT3A encodes the catalytic subunit of the STT3A-containing oligosaccharyltransferase (OST) complex, essential for protein N-glycosylation. Affected individuals presented with variable skeletal anomalies, short stature, macrocephaly, and dysmorphic features; half had intellectual disability. Additional features included increased muscle tone and muscle cramps. Modeling of the variants in the 3D structure of the OST complex indicated that all variants are located in the catalytic site of STT3A, suggesting a direct mechanistic link to the transfer of oligosaccharides onto nascent glycoproteins. Indeed, expression of STT3A at mRNA and steady-state protein level in fibroblasts was normal, while glycosylation was abnormal. In S. cerevisiae, expression of STT3 containing variants homologous to those in affected individuals induced defective glycosylation of carboxypeptidase Y in a wild-type yeast strain and expression of the same mutants in the STT3 hypomorphic stt3-7 yeast strain worsened the already observed glycosylation defect. These data support a dominant pathomechanism underlying the glycosylation defect. Recessive mutations in STT3A have previously been described to lead to a CDG. We present here a dominant form of STT3A-CDG that, because of the presence of abnormal transferrin glycoforms, is unusual among dominant type I CDGs.
Collapse
|
23
|
Honer J, Niemeyer KM, Fercher C, Diez Tissera AL, Jaberolansar N, Jafrani YMA, Zhou C, Caramelo JJ, Shewan AM, Schulz BL, Brodsky JL, Zacchi LF. TorsinA folding and N-linked glycosylation are sensitive to redox homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119073. [PMID: 34062155 PMCID: PMC8889903 DOI: 10.1016/j.bbamcr.2021.119073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 01/03/2023]
Abstract
The Endoplasmic Reticulum (ER) is responsible for the folding and post-translational modification of secretory proteins, as well as for triaging misfolded proteins. During folding, there is a complex yet only partially understood interplay between disulfide bond formation, which is an enzyme catalyzed event in the oxidizing environment of the ER, along with other post-translational modifications (PTMs) and chaperone-supported protein folding. Here, we used the glycoprotein torsinA as a model substrate to explore the impact of ER redox homeostasis on PTMs and protein biogenesis. TorsinA is a AAA+ ATPase with unusual oligomeric properties and controversial functions. The deletion of a C-terminal glutamic acid residue (∆E) is associated with the development of Early-Onset Torsion Dystonia, a severe movement disorder. TorsinA differs from other AAA+ ATPases since it is an ER resident, and as a result of its entry into the ER torsinA contains two N-linked glycans and at least one disulfide bond. The role of these PTMs on torsinA biogenesis and function and the identity of the enzymes that catalyze them are poorly defined. Using a yeast torsinA expression system, we demonstrate that a specific protein disulfide isomerase, Pdi1, affects the folding and N-linked glycosylation of torsinA and torsinA∆E in a redox-dependent manner, suggesting that the acquisition of early torsinA folding intermediates is sensitive to perturbed interactions between Cys residues and the quality control machinery. We also highlight the role of specific Cys residues during torsinA biogenesis and demonstrate that torsinA∆E is more sensitive than torsinA when these Cys residues are mutated.
Collapse
Affiliation(s)
- Jonas Honer
- Department of Biological Sciences, A320 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - Katie M Niemeyer
- Department of Biological Sciences, A320 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - Christian Fercher
- Australian Research Council Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Ana L Diez Tissera
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), 1405 Buenos Aires, Argentina
| | - Noushin Jaberolansar
- Australian Research Council Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Yohaann M A Jafrani
- Australian Research Council Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chun Zhou
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Julio J Caramelo
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), 1405 Buenos Aires, Argentina
| | - Annette M Shewan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Benjamin L Schulz
- Australian Research Council Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia; School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Jeffrey L Brodsky
- Department of Biological Sciences, A320 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - Lucía F Zacchi
- Department of Biological Sciences, A320 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, United States of America; Australian Research Council Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia; Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), 1405 Buenos Aires, Argentina; School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia.
| |
Collapse
|
24
|
Marinko JT, Wright MT, Schlebach JP, Clowes KR, Heintzman DR, Plate L, Sanders CR. Glycosylation limits forward trafficking of the tetraspan membrane protein PMP22. J Biol Chem 2021; 296:100719. [PMID: 33933451 PMCID: PMC8191293 DOI: 10.1016/j.jbc.2021.100719] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 02/01/2023] Open
Abstract
Peripheral myelin protein 22 (PMP22) folds and trafficks inefficiently, with only 20% of newly expressed protein trafficking to the cell surface. This behavior is exacerbated in many of the mutants associated with Charcot–Marie–Tooth disease, motivating further study. Here we characterized the role of N-glycosylation in limiting PMP22 trafficking. We first eliminated N-glycosylation using an N41Q mutation, which resulted in an almost 3-fold increase in trafficking efficiency of wildtype (WT) PMP22 and a 10-fold increase for the severely unstable L16P disease mutant in HEK293 cells, with similar results in Schwann cells. Total cellular levels were also much higher for the WT/N41Q mutant, although not for the L16P/N41Q form. Depletion of oligosaccharyltransferase OST-A and OST-B subunits revealed that WT PMP22 is N-glycosylated posttranslationally by OST-B, whereas L16P is cotranslationally glycosylated by OST-A. Quantitative proteomic screens revealed similarities and differences in the interactome for WT, glycosylation-deficient, and unstable mutant forms of PMP22 and also suggested that L16P is sequestered at earlier stages of endoplasmic reticulum quality control. CRISPR knockout studies revealed a role for retention in endoplasmic reticulum sorting receptor 1 (RER1) in limiting the trafficking of all three forms, for UDP-glucose glycoprotein glucosyltransferase 1 (UGGT1) in limiting the trafficking of WT and L16P but not N41Q, and calnexin (CNX) in limiting the trafficking of WT and N41Q but not L16P. This work shows that N-glycosylation is a limiting factor to forward trafficking PMP22 and sheds light on the proteins involved in its quality control.
Collapse
Affiliation(s)
- Justin T Marinko
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Madison T Wright
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Katherine R Clowes
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Darren R Heintzman
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA.
| |
Collapse
|
25
|
Yan P, Patel HJ, Sharma S, Corben A, Wang T, Panchal P, Yang C, Sun W, Araujo TL, Rodina A, Joshi S, Robzyk K, Gandu S, White JR, de Stanchina E, Modi S, Janjigian YY, Hill EG, Liu B, Erdjument-Bromage H, Neubert TA, Que NLS, Li Z, Gewirth DT, Taldone T, Chiosis G. Molecular Stressors Engender Protein Connectivity Dysfunction through Aberrant N-Glycosylation of a Chaperone. Cell Rep 2021; 31:107840. [PMID: 32610141 PMCID: PMC7372946 DOI: 10.1016/j.celrep.2020.107840] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/04/2020] [Accepted: 06/09/2020] [Indexed: 01/08/2023] Open
Abstract
Stresses associated with disease may pathologically remodel the proteome by both increasing interaction strength and altering interaction partners, resulting in proteome-wide connectivity dysfunctions. Chaperones play an important role in these alterations, but how these changes are executed remains largely unknown. Our study unveils a specific N-glycosylation pattern used by a chaperone, Glucose-regulated protein 94 (GRP94), to alter its conformational fitness and stabilize a state most permissive for stable interactions with proteins at the plasma membrane. This "protein assembly mutation' remodels protein networks and properties of the cell. We show in cells, human specimens, and mouse xenografts that proteome connectivity is restorable by inhibition of the N-glycosylated GRP94 variant. In summary, we provide biochemical evidence for stressor-induced chaperone-mediated protein mis-assemblies and demonstrate how these alterations are actionable in disease.
Collapse
Affiliation(s)
- Pengrong Yan
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Hardik J Patel
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sahil Sharma
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Adriana Corben
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Currently at Mount Sinai Hospital, New York, NY 10029, USA
| | - Tai Wang
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Palak Panchal
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Chenghua Yang
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Currently at Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Weilin Sun
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Thais L Araujo
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna Rodina
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Suhasini Joshi
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Kenneth Robzyk
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Srinivasa Gandu
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Julie R White
- Comparative Pathology Laboratory, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Elisa de Stanchina
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Shanu Modi
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yelena Y Janjigian
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Elizabeth G Hill
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Bei Liu
- Pelotonia Institute for Immuno-Oncology, The Ohio State University, Columbus, OH 43210, USA
| | - Hediye Erdjument-Bromage
- Department of Cell Biology and Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Thomas A Neubert
- Department of Cell Biology and Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Nanette L S Que
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| | - Zihai Li
- Pelotonia Institute for Immuno-Oncology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel T Gewirth
- Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA
| | - Tony Taldone
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Gabriela Chiosis
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| |
Collapse
|
26
|
Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) extensively N-glycosylates its spike proteins, which are necessary for host cell invasion and the target of both vaccines and immunotherapies. These N-glycans are predicted to modulate spike binding to the host receptor by stabilizing its open conformation and host immunity evasion. Here, we investigated the essentiality of both the host N-glycosylation pathway and SARS-CoV-2 N-glycans for infection. Ablation of host N-glycosylation using RNA interference or inhibitors, including FDA-approved drugs, reduced the spread of the infection, including that of variants B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta). Under these conditions, cells produced fewer virions and some completely lost their infectivity. Furthermore, partial enzymatic deglycosylation of intact virions showed that surface-exposed N-glycans are critical for cell invasion. Altogether, we propose protein N-glycosylation as a targetable pathway with clinical potential for treatment of COVID-19. IMPORTANCE The coronavirus SARS-CoV-2 uses its spike surface proteins to infect human cells. Spike proteins are heavily modified with several N-glycans, which are predicted to modulate their function. In this work, we show that interfering with either the synthesis or attachment of spike N-glycans significantly reduces the spread of SARS-CoV-2 infection in vitro, including that of several variants. As new SARS-CoV-2 variants, with various degrees of resistance against current vaccines, are likely to continue appearing, halting virus glycosylation using repurposed human drugs could result in a complementary strategy to reducing the spread of COVID-19 worldwide.
Collapse
|
27
|
Genetic glycoengineering in mammalian cells. J Biol Chem 2021; 296:100448. [PMID: 33617880 PMCID: PMC8042171 DOI: 10.1016/j.jbc.2021.100448] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 02/06/2023] Open
Abstract
Advances in nuclease-based gene-editing technologies have enabled precise, stable, and systematic genetic engineering of glycosylation capacities in mammalian cells, opening up a plethora of opportunities for studying the glycome and exploiting glycans in biomedicine. Glycoengineering using chemical, enzymatic, and genetic approaches has a long history, and precise gene editing provides a nearly unlimited playground for stable engineering of glycosylation in mammalian cells to explore and dissect the glycome and its many biological functions. Genetic engineering of glycosylation in cells also brings studies of the glycome to the single cell level and opens up wider use and integration of data in traditional omics workflows in cell biology. The last few years have seen new applications of glycoengineering in mammalian cells with perspectives for wider use in basic and applied glycosciences, and these have already led to discoveries of functions of glycans and improved designs of glycoprotein therapeutics. Here, we review the current state of the art of genetic glycoengineering in mammalian cells and highlight emerging opportunities.
Collapse
|
28
|
The Role of Endoplasmic Reticulum Chaperones in Protein Folding and Quality Control. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:27-50. [PMID: 34050861 DOI: 10.1007/978-3-030-67696-4_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Molecular chaperones assist the folding of nascent chains in the cell. Chaperones also aid in quality control decisions as persistent chaperone binding can help to sort terminal misfolded proteins for degradation. There are two major molecular chaperone families in the endoplasmic reticulum (ER) that assist proteins in reaching their native structure and evaluating the fidelity of the maturation process. The ER Hsp70 chaperone, BiP, supports adenine nucleotide-regulated binding to non-native proteins that possess exposed hydrophobic regions. In contrast, the carbohydrate-dependent chaperone system involving the membrane protein calnexin and its soluble paralogue calreticulin recognize a specific glycoform of an exposed hydrophilic protein modification for which the composition is controlled by a series of glycosidases and transferases. Here, we compare and contrast the properties, mechanisms of action and functions of these different chaperones systems that work in parallel, as well as together, to assist a large variety of substrates that traverse the eukaryotic secretory pathway.
Collapse
|
29
|
Adams BM, Canniff NP, Guay KP, Larsen ISB, Hebert DN. Quantitative glycoproteomics reveals cellular substrate selectivity of the ER protein quality control sensors UGGT1 and UGGT2. eLife 2020; 9:e63997. [PMID: 33320095 PMCID: PMC7771966 DOI: 10.7554/elife.63997] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
UDP-glucose:glycoprotein glucosyltransferase (UGGT) 1 and 2 are central hubs in the chaperone network of the endoplasmic reticulum (ER), acting as gatekeepers to the early secretory pathway, yet little is known about their cellular clients. These two quality control sensors control lectin chaperone binding and glycoprotein egress from the ER. A quantitative glycoproteomics strategy was deployed to identify cellular substrates of the UGGTs at endogenous levels in CRISPR-edited HEK293 cells. The 71 UGGT substrates identified were mainly large multidomain and heavily glycosylated proteins when compared to the general N-glycoproteome. UGGT1 was the dominant glucosyltransferase with a preference toward large plasma membrane proteins whereas UGGT2 favored the modification of smaller, soluble lysosomal proteins. This study sheds light on differential specificities and roles of UGGT1 and UGGT2 and provides insight into the cellular reliance on the carbohydrate-dependent chaperone system to facilitate proper folding and maturation of the cellular N-glycoproteome.
Collapse
Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Nathan P Canniff
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Kevin P Guay
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Ida Signe Bohse Larsen
- Department of Cellular and Molecular Medicine, University of CopenhagenCopenhagenDenmark
- Copenhagen Center for Glycomics, University of CopenhagenCopenhagenDenmark
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| |
Collapse
|
30
|
Thomas D, Rathinavel AK, Radhakrishnan P. Altered glycosylation in cancer: A promising target for biomarkers and therapeutics. Biochim Biophys Acta Rev Cancer 2020; 1875:188464. [PMID: 33157161 DOI: 10.1016/j.bbcan.2020.188464] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/08/2020] [Accepted: 10/28/2020] [Indexed: 12/13/2022]
Abstract
Glycosylation is a well-regulated cell and microenvironment specific post-translational modification. Several glycosyltransferases and glycosidases orchestrate the addition of defined glycan structures on the proteins and lipids. Recent advances and systemic approaches in glycomics have significantly contributed to a better understanding of instrumental roles of glycans in health and diseases. Emerging research evidence recognized aberrantly glycosylated proteins as the modulators of the malignant phenotype of cancer cells. The Cancer Genome Atlas has identified alterations in the expressions of glycosylation-specific genes that are correlated with cancer progression. However, the mechanistic basis remains poorly explored. Recent researches have shown that specific changes in the glycan structures are associated with 'stemness' and epithelial-to-mesenchymal transition of cancer cells. Moreover, epigenetic changes in the glycosylation pattern make the tumor cells capable of escaping immunosurveillance mechanisms. The deciphering roles of glycans in cancer emphasize that glycans can serve as a source for the development of novel clinical biomarkers. The ability of glycans in intervening various stages of tumor progression and the biosynthetic pathways involved in glycan structures constitute a promising target for cancer therapy. Advances in the knowledge of innovative strategies for identifying the mechanisms of glycan-binding proteins are hoped to hold great potential in cancer therapy. This review discusses the fundamental role of glycans in regulating tumorigenesis and tumor progression and provides insights into the influence of glycans in the current tactics of targeted therapies in the clinical setting.
Collapse
Affiliation(s)
- Divya Thomas
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Ashok Kumar Rathinavel
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Prakash Radhakrishnan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| |
Collapse
|
31
|
Jiao Q, Chen T, Niu G, Zhang H, Zhou C, Hong Z. N-glycosylation is involved in stomatal development by modulating the release of active abscisic acid and auxin in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5865-5879. [PMID: 32649744 DOI: 10.1093/jxb/eraa321] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/09/2020] [Indexed: 05/11/2023]
Abstract
Asparagine-linked glycosylation (N-glycosylation) is one of the most important protein modifications in eukaryotes, affecting the folding, transport, and function of a wide range of proteins. However, little is known about the roles of N-glycosylation in the development of stomata in plants. In the present study, we provide evidence that the Arabidopsis stt3a-2 mutant, defective in oligosaccharyltransferase catalytic subunit STT3, has a greater transpirational water loss and weaker drought avoidance, accompanied by aberrant stomatal distribution. Through physiological, biochemical, and genetic analyses, we found that the abnormal stomatal density of stt3a-2 was partially attributed to low endogenous abscisic acid (ABA) and auxin (IAA) content. Exogenous application of ABA or IAA could partially rescue the mutant's salt-sensitive and abnormal stomatal phenotype. Further analyses revealed that the decrease of IAA or ABA in stt3a-2 seedlings was associated with the underglycosylation of β-glucosidase (AtBG1), catalysing the conversion of conjugated ABA/IAA to active hormone. Our results provide strong evidence that N-glycosylation is involved in stomatal development and participates in abiotic stress tolerance by modulating the release of active plant hormones.
Collapse
Affiliation(s)
- Qingsong Jiao
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| | - Tianshu Chen
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| | - Guanting Niu
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| | - Huchen Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| | - ChangFang Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| | - Zhi Hong
- State Key Laboratory of Pharmaceutical Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China
| |
Collapse
|
32
|
McGilvray PT, Anghel SA, Sundaram A, Zhong F, Trnka MJ, Fuller JR, Hu H, Burlingame AL, Keenan RJ. An ER translocon for multi-pass membrane protein biogenesis. eLife 2020; 9:e56889. [PMID: 32820719 PMCID: PMC7505659 DOI: 10.7554/elife.56889] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/20/2020] [Indexed: 12/23/2022] Open
Abstract
Membrane proteins with multiple transmembrane domains play critical roles in cell physiology, but little is known about the machinery coordinating their biogenesis at the endoplasmic reticulum. Here we describe a ~ 360 kDa ribosome-associated complex comprising the core Sec61 channel and five accessory factors: TMCO1, CCDC47 and the Nicalin-TMEM147-NOMO complex. Cryo-electron microscopy reveals a large assembly at the ribosome exit tunnel organized around a central membrane cavity. Similar to protein-conducting channels that facilitate movement of transmembrane segments, cytosolic and luminal funnels in TMCO1 and TMEM147, respectively, suggest routes into the central membrane cavity. High-throughput mRNA sequencing shows selective translocon engagement with hundreds of different multi-pass membrane proteins. Consistent with a role in multi-pass membrane protein biogenesis, cells lacking different accessory components show reduced levels of one such client, the glutamate transporter EAAT1. These results identify a new human translocon and provide a molecular framework for understanding its role in multi-pass membrane protein biogenesis.
Collapse
Affiliation(s)
- Philip T McGilvray
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - S Andrei Anghel
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
- Department of Molecular Genetics and Cell Biology, The University of ChicagoChicagoUnited States
| | - Arunkumar Sundaram
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Frank Zhong
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
- Department of Molecular Genetics and Cell Biology, The University of ChicagoChicagoUnited States
| | - Michael J Trnka
- Department of Pharmaceutical Chemistry, University of California, San FranciscoSan FranciscoUnited States
| | - James R Fuller
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Hong Hu
- Center for Research Informatics, The University of ChicagoChicagoUnited States
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San FranciscoSan FranciscoUnited States
| | - Robert J Keenan
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| |
Collapse
|
33
|
Ravell JC, Chauvin SD, He T, Lenardo M. An Update on XMEN Disease. J Clin Immunol 2020; 40:671-681. [PMID: 32451662 PMCID: PMC7369250 DOI: 10.1007/s10875-020-00790-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/07/2020] [Indexed: 12/23/2022]
Abstract
“X-linked immunodeficiency with magnesium defect, Epstein-Barr virus (EBV) infection, and neoplasia” (XMEN) disease is an inborn error of glycosylation and immunity caused by loss of function mutations in the magnesium transporter 1 (MAGT1) gene. It is a multisystem disease that strongly affects certain immune cells. MAGT1 is now confirmed as a non-catalytic subunit of the oligosaccharyltransferase complex and facilitates Asparagine (N)-linked glycosylation of specific substrates, making XMEN a congenital disorder of glycosylation manifesting as a combined immune deficiency. The clinical disease has variable expressivity and impaired glycosylation of key MAGT1-dependent glycoproteins in addition to Mg2+ abnormalities can explain some of the immune manifestations. NKG2D, an activating receptor critical for cytotoxic function against EBV, is poorly glycosylated and invariably decreased on CD8+ T cells and natural killer (NK) cells from XMEN patients. It is the best biomarker of the disease. The characterization of EBV-naïve XMEN patients has clarified features of the genetic disease that were previously attributed to EBV infection. Extra-immune manifestations, including hepatic and neurological abnormalities have recently been reported. EBV-associated lymphomas remain the main cause of severe morbidity. Unfortunately, treatment options to address the underlying mechanism of disease remain limited and Mg2+ supplementation has not proven successful. Here, we review the expanding clinical phenotype and recent advances in glycobiology that have increased our understanding of XMEN disease. We also propose updating XMEN to “X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect” in light of these novel findings.
Collapse
Affiliation(s)
- Juan C Ravell
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research (DIR), National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA
| | - Samuel D Chauvin
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, DIR, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA
| | - Tingyan He
- Department of Rheumatology and Immunology, Shenzhen Children's Hospital, Shenzhen, 518038, China.
| | - Michael Lenardo
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, DIR, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA.
| |
Collapse
|
34
|
Structural Insight into the Mechanism of N-Linked Glycosylation by Oligosaccharyltransferase. Biomolecules 2020; 10:biom10040624. [PMID: 32316603 PMCID: PMC7226087 DOI: 10.3390/biom10040624] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/06/2020] [Accepted: 04/10/2020] [Indexed: 02/06/2023] Open
Abstract
Asparagine-linked glycosylation, also known as N-linked glycosylation is an essential and highly conserved post-translational protein modification that occurs in all three domains of life. This modification is essential for specific molecular recognition, protein folding, sorting in the endoplasmic reticulum, cell-cell communication, and stability. Defects in N-linked glycosylation results in a class of inherited diseases known as congenital disorders of glycosylation (CDG). N-linked glycosylation occurs in the endoplasmic reticulum (ER) lumen by a membrane associated enzyme complex called the oligosaccharyltransferase (OST). In the central step of this reaction, an oligosaccharide group is transferred from a lipid-linked dolichol pyrophosphate donor to the acceptor substrate, the side chain of a specific asparagine residue of a newly synthesized protein. The prokaryotic OST enzyme consists of a single polypeptide chain, also known as single subunit OST or ssOST. In contrast, the eukaryotic OST is a complex of multiple non-identical subunits. In this review, we will discuss the biochemical and structural characterization of the prokaryotic, yeast, and mammalian OST enzymes. This review explains the most recent high-resolution structures of OST determined thus far and the mechanistic implication of N-linked glycosylation throughout all domains of life. It has been shown that the ssOST enzyme, AglB protein of the archaeon Archaeoglobus fulgidus, and the PglB protein of the bacterium Campylobactor lari are structurally and functionally similar to the catalytic Stt3 subunit of the eukaryotic OST enzyme complex. Yeast OST enzyme complex contains a single Stt3 subunit, whereas the human OST complex is formed with either STT3A or STT3B, two paralogues of Stt3. Both human OST complexes, OST-A (with STT3A) and OST-B (containing STT3B), are involved in the N-linked glycosylation of proteins in the ER. The cryo-EM structures of both human OST-A and OST-B complexes were reported recently. An acceptor peptide and a donor substrate (dolichylphosphate) were observed to be bound to the OST-B complex whereas only dolichylphosphate was bound to the OST-A complex suggesting disparate affinities of two OST complexes for the acceptor substrates. However, we still lack an understanding of the independent role of each eukaryotic OST subunit in N-linked glycosylation or in the stabilization of the enzyme complex. Discerning the role of each subunit through structure and function studies will potentially reveal the mechanistic details of N-linked glycosylation in higher organisms. Thus, getting an insight into the requirement of multiple non-identical subunits in the N-linked glycosylation process in eukaryotes poses an important future goal.
Collapse
|
35
|
Knopf JD, Landscheidt N, Pegg CL, Schulz BL, Kühnle N, Chao CW, Huck S, Lemberg MK. Intramembrane protease RHBDL4 cleaves oligosaccharyltransferase subunits to target them for ER-associated degradation. J Cell Sci 2020; 133:jcs243790. [PMID: 32005703 DOI: 10.1242/jcs.243790] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 01/21/2020] [Indexed: 08/31/2023] Open
Abstract
The endoplasmic reticulum (ER)-resident intramembrane rhomboid protease RHBDL4 generates metastable protein fragments and together with the ER-associated degradation (ERAD) machinery provides a clearance mechanism for aberrant and surplus proteins. However, the endogenous substrate spectrum and with that the role of RHBDL4 in physiological ERAD is mainly unknown. Here, we use a substrate trapping approach in combination with quantitative proteomics to identify physiological RHBDL4 substrates. This revealed oligosaccharyltransferase (OST) complex subunits such as the catalytic active subunit STT3A as substrates for the RHBDL4-dependent ERAD pathway. RHBDL4-catalysed cleavage inactivates OST subunits by triggering dislocation into the cytoplasm and subsequent proteasomal degradation. RHBDL4 thereby controls the abundance and activity of OST, suggesting a novel link between the ERAD machinery and glycosylation tuning.
Collapse
Affiliation(s)
- Julia D Knopf
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Nina Landscheidt
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Cassandra L Pegg
- School of Chemistry and Molecular Biosciences, ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Benjamin L Schulz
- School of Chemistry and Molecular Biosciences, ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Nathalie Kühnle
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Chao-Wei Chao
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Simon Huck
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| |
Collapse
|
36
|
Ravell JC, Matsuda-Lennikov M, Chauvin SD, Zou J, Biancalana M, Deeb SJ, Price S, Su HC, Notarangelo G, Jiang P, Morawski A, Kanellopoulou C, Binder K, Mukherjee R, Anibal JT, Sellers B, Zheng L, He T, George AB, Pittaluga S, Powers A, Kleiner DE, Kapuria D, Ghany M, Hunsberger S, Cohen JI, Uzel G, Bergerson J, Wolfe L, Toro C, Gahl W, Folio LR, Matthews H, Angelus P, Chinn IK, Orange JS, Trujillo-Vargas CM, Franco JL, Orrego-Arango J, Gutiérrez-Hincapié S, Patel NC, Raymond K, Patiroglu T, Unal E, Karakukcu M, Day AG, Mehta P, Masutani E, De Ravin SS, Malech HL, Altan-Bonnet G, Rao VK, Mann M, Lenardo MJ. Defective glycosylation and multisystem abnormalities characterize the primary immunodeficiency XMEN disease. J Clin Invest 2020; 130:507-522. [PMID: 31714901 PMCID: PMC6934229 DOI: 10.1172/jci131116] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/18/2019] [Indexed: 01/01/2023] Open
Abstract
X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN) disease are caused by deficiency of the magnesium transporter 1 (MAGT1) gene. We studied 23 patients with XMEN, 8 of whom were EBV naive. We observed lymphadenopathy (LAD), cytopenias, liver disease, cavum septum pellucidum (CSP), and increased CD4-CD8-B220-TCRαβ+ T cells (αβDNTs), in addition to the previously described features of an inverted CD4/CD8 ratio, CD4+ T lymphocytopenia, increased B cells, dysgammaglobulinemia, and decreased expression of the natural killer group 2, member D (NKG2D) receptor. EBV-associated B cell malignancies occurred frequently in EBV-infected patients. We studied patients with XMEN and patients with autoimmune lymphoproliferative syndrome (ALPS) by deep immunophenotyping (32 immune markers) using time-of-flight mass cytometry (CyTOF). Our analysis revealed that the abundance of 2 populations of naive B cells (CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4++CD10+CD38+ and CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4+CD10-CD38-) could differentially classify XMEN, ALPS, and healthy individuals. We also performed glycoproteomics analysis on T lymphocytes and show that XMEN disease is a congenital disorder of glycosylation that affects a restricted subset of glycoproteins. Transfection of MAGT1 mRNA enabled us to rescue proteins with defective glycosylation. Together, these data provide new clinical and pathophysiological foundations with important ramifications for the diagnosis and treatment of XMEN disease.
Collapse
Affiliation(s)
- Juan C. Ravell
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Mami Matsuda-Lennikov
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Samuel D. Chauvin
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Juan Zou
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Matthew Biancalana
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Sally J. Deeb
- Proteomics and Signal Transduction Group and Computational Systems Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Susan Price
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Helen C. Su
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Giulia Notarangelo
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Ping Jiang
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Aaron Morawski
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Chrysi Kanellopoulou
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Kyle Binder
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, Maryland, USA
| | - Ratnadeep Mukherjee
- Center for Cancer Research, National Cancer Institute (NCI), Bethesda, Maryland, USA
| | - James T. Anibal
- Center for Cancer Research, National Cancer Institute (NCI), Bethesda, Maryland, USA
| | - Brian Sellers
- Trans-NIH Center for Human Immunology, Autoimmunity, and Inflammation, NIH, Bethesda, Maryland, USA
| | - Lixin Zheng
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Tingyan He
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
- Department of Rheumatology and Immunology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Alex B. George
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Stefania Pittaluga
- Hematopathology Section, Laboratory of Pathology, NCI, Bethesda, Maryland, USA
| | - Astin Powers
- Laboratory of Pathology, NCI, Bethesda, Maryland, USA
| | | | - Devika Kapuria
- Liver Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Marc Ghany
- Liver Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | | | - Jeffrey I. Cohen
- Medical Virology Section, Laboratory of Infectious Diseases, NIAID
| | - Gulbu Uzel
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Jenna Bergerson
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Lynne Wolfe
- National Human Genome Research Institute, and
| | - Camilo Toro
- National Human Genome Research Institute, and
| | | | - Les R. Folio
- Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, Maryland, USA
| | - Helen Matthews
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Pam Angelus
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
- Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, NCI, NIH, Bethesda, Maryland, USA
| | - Ivan K. Chinn
- Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Jordan S. Orange
- Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Claudia M. Trujillo-Vargas
- Grupo de Inmunodeficiencias Primarias, Facultad de Medicina, Universidad de Antioquia UdeA, Medellin, Colombia
| | - Jose Luis Franco
- Grupo de Inmunodeficiencias Primarias, Facultad de Medicina, Universidad de Antioquia UdeA, Medellin, Colombia
| | - Julio Orrego-Arango
- Grupo de Inmunodeficiencias Primarias, Facultad de Medicina, Universidad de Antioquia UdeA, Medellin, Colombia
| | | | - Niraj Chandrakant Patel
- Section of Infectious Disease and Immunology, Department of Pediatrics, Carolinas Medical Center, and
- Levine Children’s Hospital Atrium Health, Charlotte, North Carolina, USA
| | - Kimiyo Raymond
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Turkan Patiroglu
- Department of Pediatrics, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Ekrem Unal
- Department of Pediatrics, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Musa Karakukcu
- Department of Pediatrics, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | | | - Pankaj Mehta
- Department of Physics, Boston University, Boston, Massachusetts, USA
| | - Evan Masutani
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Suk S. De Ravin
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Harry L. Malech
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Grégoire Altan-Bonnet
- Center for Cancer Research, National Cancer Institute (NCI), Bethesda, Maryland, USA
| | - V. Koneti Rao
- Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, NIAID, Bethesda, Maryland, USA
| | - Matthias Mann
- Proteomics and Signal Transduction Group and Computational Systems Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Michael J. Lenardo
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, and Clinical Genomics Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| |
Collapse
|
37
|
Ramírez AS, Kowal J, Locher KP. Cryo–electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B. Science 2019; 366:1372-1375. [DOI: 10.1126/science.aaz3505] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022]
Abstract
Oligosaccharyltransferase (OST) catalyzes the transfer of a high-mannose glycan onto secretory proteins in the endoplasmic reticulum. Mammals express two distinct OST complexes that act in a cotranslational (OST-A) or posttranslocational (OST-B) manner. Here, we present high-resolution cryo–electron microscopy structures of human OST-A and OST-B. Although they have similar overall architectures, structural differences in the catalytic subunits STT3A and STT3B facilitate contacts to distinct OST subunits, DC2 in OST-A and MAGT1 in OST-B. In OST-A, interactions with TMEM258 and STT3A allow ribophorin-I to form a four-helix bundle that can bind to a translating ribosome, whereas the equivalent region is disordered in OST-B. We observed an acceptor peptide and dolichylphosphate bound to STT3B, but only dolichylphosphate in STT3A, suggesting distinct affinities of the two OST complexes for protein substrates.
Collapse
Affiliation(s)
- Ana S. Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Julia Kowal
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Kaspar P. Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| |
Collapse
|
38
|
Shrimal S, Cherepanova NA, Mandon EC, Venev SV, Gilmore R. Asparagine-linked glycosylation is not directly coupled to protein translocation across the endoplasmic reticulum in Saccharomyces cerevisiae. Mol Biol Cell 2019; 30:2626-2638. [PMID: 31433728 PMCID: PMC6761772 DOI: 10.1091/mbc.e19-06-0330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mammalian cells express two oligosaccharyltransferase complexes, STT3A and STT3B, that have distinct roles in N-linked glycosylation. The STT3A complex interacts directly with the protein translocation channel to mediate glycosylation of proteins using an N-terminal-to-C-terminal scanning mechanism. N-linked glycosylation of proteins in budding yeast has been assumed to be a cotranslational reaction. We have compared glycosylation of several glycoproteins in yeast and mammalian cells. Prosaposin, a cysteine-rich protein that contains STT3A-dependent glycosylation sites, is poorly glycosylated in yeast cells and STT3A-deficient human cells. In contrast, a protein with extreme C-terminal glycosylation sites was efficiently glycosylated in yeast by a posttranslocational mechanism. Posttranslocational glycosylation was also observed for carboxypeptidase Y-derived reporter proteins that contain closely spaced acceptor sites. A comparison of two recent protein structures indicates that the yeast OST is unable to interact with the yeast heptameric Sec complex via an evolutionarily conserved interface due to occupation of the OST binding site by the Sec63 protein. The efficiency of glycosylation in yeast is not enhanced for proteins that are translocated by the Sec61 or Ssh1 translocation channels instead of the Sec complex. We conclude that N-linked glycosylation and protein translocation are not directly coupled in yeast cells.
Collapse
Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Elisabet C Mandon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sergey V Venev
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| |
Collapse
|