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Meling MT, Kleppa L, Besser HA, Khosla C, du Pré MF, Sollid LM. Enterocyte-Derived and Catalytically Active Transglutaminase 2 in the Gut Lumen of Mice: Implications for Celiac Disease. Gastroenterology 2024; 167:1026-1028.e4. [PMID: 38825048 DOI: 10.1053/j.gastro.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/29/2024] [Accepted: 05/24/2024] [Indexed: 06/04/2024]
Affiliation(s)
- Maureen T Meling
- Norwegian Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Immunology, Oslo University Hospital, Oslo, Norway
| | - Liv Kleppa
- Norwegian Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Immunology, Oslo University Hospital, Oslo, Norway
| | - Harrison A Besser
- Department of Chemistry, Stanford University, Stanford, California; Stanford Medical Scientist Training Program, Stanford University School of Medicine, Stanford, California
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, California; Department of Chemical Engineering, Stanford University, Stanford, California; Sarafan ChEM-H, Stanford University, Stanford, California
| | - M Fleur du Pré
- Norwegian Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Immunology, Oslo University Hospital, Oslo, Norway
| | - Ludvig M Sollid
- Norwegian Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Immunology, Oslo University Hospital, Oslo, Norway.
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2
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Sewa AS, Besser HA, Mathews II, Khosla C. Structural and mechanistic analysis of Ca 2+-dependent regulation of transglutaminase 2 activity using a Ca 2+-bound intermediate state. Proc Natl Acad Sci U S A 2024; 121:e2407066121. [PMID: 38959038 PMCID: PMC11252922 DOI: 10.1073/pnas.2407066121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 06/07/2024] [Indexed: 07/04/2024] Open
Abstract
Mammalian transglutaminases, a family of Ca2+-dependent proteins, are implicated in a variety of diseases. For example, celiac disease (CeD) is an autoimmune disorder whose pathogenesis requires transglutaminase 2 (TG2) to deamidate select glutamine residues in diet-derived gluten peptides. Deamidation involves the formation of transient γ-glutamyl thioester intermediates. Recent studies have revealed that in addition to the deamidated gluten peptides themselves, their corresponding thioester intermediates are also pathogenically relevant. A mechanistic understanding of this relevance is hindered by the absence of any structure of Ca2+-bound TG2. We report the X-ray crystallographic structure of human TG2 bound to an inhibitory gluten peptidomimetic and two Ca2+ ions in sites previously designated as S1 and S3. Together with additional structure-guided experiments, this structure provides a mechanistic explanation for how S1 regulates formation of an inhibitory disulfide bond in TG2, while also establishing that S3 is essential for γ-glutamyl thioester formation. Furthermore, our crystallographic findings and associated analyses have revealed that i) two interacting residues, H305 and E363, play a critical role in resolving the thioester intermediate into an isopeptide bond (transamidation) but not in thioester hydrolysis (deamidation); and ii) residues N333 and K176 stabilize preferred TG2 substrates and inhibitors via hydrogen bonding to nonreactive backbone atoms. Overall, the intermediate-state conformer of TG2 reported here represents a superior model to previously characterized conformers for both transition states of the TG2-catalyzed reaction.
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Affiliation(s)
- Agnele S. Sewa
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
| | - Harrison A. Besser
- Department of Chemistry, Stanford University, Stanford, CA94305
- Stanford Medical Scientist Training Program, Stanford University School of Medicine, Stanford, CA94305
| | - Irimpan I. Mathews
- Stanford Synchrotron Radiation Lightsource, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA94025
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA94305
- Department of Chemical Engineering, Stanford University, Stanford, CA94305
- Sarafan Chemistry, Engineering Medicine and Human Health, Stanford University, Stanford, CA94305
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Yao Z, Fan Y, Lin L, Kellems RE, Xia Y. Tissue transglutaminase: a multifunctional and multisite regulator in health and disease. Physiol Rev 2024; 104:281-325. [PMID: 37712623 DOI: 10.1152/physrev.00003.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/07/2023] [Accepted: 09/10/2023] [Indexed: 09/16/2023] Open
Abstract
Tissue transglutaminase (TG2) is a widely distributed multifunctional protein involved in a broad range of cellular and metabolic functions carried out in a variety of cellular compartments. In addition to transamidation, TG2 also functions as a Gα signaling protein, a protein disulfide isomerase (PDI), a protein kinase, and a scaffolding protein. In the nucleus, TG2 modifies histones and transcription factors. The PDI function catalyzes the trimerization and activation of heat shock factor-1 in the nucleus and regulates the oxidation state of several mitochondrial complexes. Cytosolic TG2 modifies proteins by the addition of serotonin or other primary amines and in this way affects cell signaling. Modification of protein-bound glutamines reduces ubiquitin-dependent proteasomal degradation. At the cell membrane, TG2 is associated with G protein-coupled receptors (GPCRs), where it functions in transmembrane signaling. TG2 is also found in the extracellular space, where it functions in protein cross-linking and extracellular matrix stabilization. Of particular importance in transglutaminase research are recent findings concerning the role of TG2 in gene expression, protein homeostasis, cell signaling, autoimmunity, inflammation, and hypoxia. Thus, TG2 performs a multitude of functions in multiple cellular compartments, making it one of the most versatile cellular proteins. Additional evidence links TG2 with multiple human diseases including preeclampsia, hypertension, cardiovascular disease, organ fibrosis, cancer, neurodegenerative diseases, and celiac disease. In conclusion, TG2 provides a multifunctional and multisite response to physiological stress.
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Affiliation(s)
- Zhouzhou Yao
- National Medical Metabolomics International Collaborative Research Center, Central South University, Changsha, Hunan, People's Republic of China
- Department of Otolaryngology-Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Yuhua Fan
- National Medical Metabolomics International Collaborative Research Center, Central South University, Changsha, Hunan, People's Republic of China
- Department of Otolaryngology-Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Lizhen Lin
- National Medical Metabolomics International Collaborative Research Center, Central South University, Changsha, Hunan, People's Republic of China
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Rodney E Kellems
- Department of Biochemistry and Molecular Biology, The University of Texas McGovern Medical School at Houston, Houston, Texas, United States
| | - Yang Xia
- National Medical Metabolomics International Collaborative Research Center, Central South University, Changsha, Hunan, People's Republic of China
- Department of Otolaryngology-Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
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Besser HA, Khosla C. Celiac disease: mechanisms and emerging therapeutics. Trends Pharmacol Sci 2023; 44:949-962. [PMID: 37839914 PMCID: PMC10843302 DOI: 10.1016/j.tips.2023.09.006] [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: 09/01/2023] [Revised: 09/14/2023] [Accepted: 09/20/2023] [Indexed: 10/17/2023]
Abstract
Celiac disease (CeD) is a widespread, gluten-induced, autoimmune disorder that lacks any medicinal therapy. Towards the goal of developing non-dietary treatments for CeD, research has focused on elucidating its molecular and cellular etiology. A model of pathogenesis has emerged centered on interactions between three molecular families: specific class II MHC proteins on antigen-presenting cells (APCs), deamidated gluten-derived peptides, and T cell receptors (TCRs) on inflammatory CD4+ T cells. Growing evidence suggests that this pathogenic axis can be pharmacologically targeted to protect patients from some of the adverse effects of dietary gluten. Further studies have revealed the existence of additional host and environmental contributors to disease initiation and tissue damage. This review summarizes our current understanding of CeD pathogenesis and how it is being harnessed for therapeutic design and development.
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Affiliation(s)
- Harrison A Besser
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Stanford Medical Scientist Training Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Sarafan ChEM-H (Chemistry, Engineering and Medicine for Human Health), Stanford University, Stanford, CA 94305, USA.
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5
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Heggelund JE, Das S, Stamnaes J, Iversen R, Sollid LM. Autoantibody binding and unique enzyme-substrate intermediate conformation of human transglutaminase 3. Nat Commun 2023; 14:6216. [PMID: 37798283 PMCID: PMC10556103 DOI: 10.1038/s41467-023-42004-z] [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: 06/20/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
Transglutaminase 3 (TG3), the autoantigen of dermatitis herpetiformis (DH), is a calcium dependent enzyme that targets glutamine residues in polypeptides for either transamidation or deamidation modifications. To become catalytically active TG3 requires proteolytic cleavage between the core domain and two C-terminal β-barrels (C1C2). Here, we report four X-ray crystal structures representing inactive and active conformations of human TG3 in complex with a TG3-specific Fab fragment of a DH patient derived antibody. We demonstrate that cleaved TG3, upon binding of a substrate-mimicking inhibitor, undergoes a large conformational change as a β-sheet in the catalytic core domain moves and C1C2 detaches. The unique enzyme-substrate conformation of TG3 without C1C2 is recognized by DH autoantibodies. The findings support a model where B-cell receptors of TG3-specific B cells bind and internalize TG3-gluten enzyme-substrate complexes thereby facilitating gluten-antigen presentation, T-cell help and autoantibody production.
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Affiliation(s)
- Julie Elisabeth Heggelund
- KG Jebsen Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
- Department of Immunology, Oslo University Hospital-Rikshospitalet, Oslo, Norway.
| | - Saykat Das
- KG Jebsen Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Immunology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
| | - Jorunn Stamnaes
- KG Jebsen Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Immunology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
| | - Rasmus Iversen
- KG Jebsen Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Immunology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
| | - Ludvig M Sollid
- KG Jebsen Coeliac Disease Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
- Department of Immunology, Oslo University Hospital-Rikshospitalet, Oslo, Norway.
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Loppinet E, Besser HA, Lee CE, Zhang W, Cui B, Khosla C. Targeted Lysosomal Degradation of Secreted and Cell Surface Proteins through the LRP-1 Pathway. J Am Chem Soc 2023; 145:18705-18710. [PMID: 37590164 PMCID: PMC10809789 DOI: 10.1021/jacs.3c05109] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Protein dysregulation has been characterized as the cause of pathogenesis in many different diseases. For proteins lacking easily druggable pockets or catalytically active sites, targeted protein degradation is an attractive therapeutic approach. While several methods for targeted protein degradation have been developed, there remains a demand for lower molecular weight molecules that promote efficient degradation of their targets. In this work, we describe the synthesis and validation of a series of heterobifunctional molecules that bind a protein of interest through a small molecule ligand while targeting them to the lysosome using a short gluten peptide that leverages the TG2/LRP-1 pathway. We demonstrate that this approach can be used to effectively endocytose and degrade representative secreted, cell surface, and transmembrane proteins, notably streptavidin, the vitamin B12 receptor, cubilin, and integrin αvβ5. Optimization of these prototypical molecules could generate pharmacologically relevant LYTAC agents.
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Affiliation(s)
- Elise Loppinet
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Harrison A Besser
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Medical Scientist Training Program, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Christina E Lee
- Biophysics Program, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Wei Zhang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Sarafan ChEM-H, Stanford University, Stanford, California 94305, United States
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