1
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Sharrouf K, Schlosser C, Mildenberger S, Fluhrer R, Hoeppner S. In vitro cleavage of tumor necrosis factor α (TNFα) by Signal-Peptide-Peptidase-like 2b (SPPL2b) resembles mechanistic principles observed in the cellular context. Chem Biol Interact 2024; 395:111006. [PMID: 38636792 DOI: 10.1016/j.cbi.2024.111006] [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: 12/22/2023] [Revised: 03/27/2024] [Accepted: 04/14/2024] [Indexed: 04/20/2024]
Abstract
Members of the Signal Peptide-Peptidase (SPP) and Signal Peptide-Peptidase-like (SPPL) family are intramembrane aspartyl-proteases like their well-studied homologs, the presenilins, which comprise the catalytically active subunit within the γ-secretase complex. The lack of in vitro cleavage assays for SPPL proteases limited their biochemical characterization as well as substrate identification and validation. So far, SPPL proteases have been analyzed exclusively in intact cells or membranes, restricting mechanistic analysis to co-expression of enzyme and substrate variants colocalizing in the same subcellular compartments. We describe the details of developing an in vitro cleavage assay for SPPL2b and its model substrate TNFα and analyzed the influence of phospholipids, detergent supplements, and cholesterol on the SPPL2b in vitro activity. SPPL2b in vitro activity resembles mechanistic principles that have been observed in a cellular context, such as cleavage sites and consecutive turnover of the TNFα transmembrane domain. The novel in vitro cleavage assay is functional with separately isolated protease and substrate and amenable to a high throughput plate-based readout overcoming previous limitations and providing the basis for studying enzyme kinetics, catalytic activity, substrate recognition, and the characteristics of small molecule inhibitors. As a proof of concept, we present the first biochemical in vitro characterization of the SPPL2a and SPPL2b specific small molecule inhibitor SPL-707.
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Affiliation(s)
- Kinda Sharrouf
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, D-86159, Augsburg, Germany
| | - Christine Schlosser
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, D-86159, Augsburg, Germany
| | - Sandra Mildenberger
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, D-86159, Augsburg, Germany; Institut für Entwicklungsbiologie und Neurobiologie, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch-Weg 15, 55099, Mainz, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, D-86159, Augsburg, Germany; University of Augsburg, Center for Interdisciplinary Health Research, 86135, Augsburg, Germany
| | - Sabine Hoeppner
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, D-86159, Augsburg, Germany.
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2
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Maccioni R, Travisan C, Badman J, Zerial S, Wagener A, Andrade-Talavera Y, Picciau F, Grassi C, Chen G, Lemoine L, Fisahn A, Jiang R, Fluhrer R, Mentrup T, Schröder B, Nilsson P, Tambaro S. Signal peptide peptidase-like 2b modulates the amyloidogenic pathway and exhibits an Aβ-dependent expression in Alzheimer's disease. Prog Neurobiol 2024; 235:102585. [PMID: 38367747 DOI: 10.1016/j.pneurobio.2024.102585] [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: 06/30/2023] [Revised: 01/25/2024] [Accepted: 02/08/2024] [Indexed: 02/19/2024]
Abstract
Alzheimer's disease (AD) is a multifactorial disorder driven by abnormal amyloid β-peptide (Aβ) levels. In this study, we investigated the role of presenilin-like signal peptide peptidase-like 2b (SPPL2b) in AD pathophysiology and its potential as a druggable target within the Aβ cascade. Exogenous Aβ42 influenced SPPL2b expression in human cell lines and acute mouse brain slices. SPPL2b and its AD-related substrate BRI2 were evaluated in the brains of AppNL-G-F knock-in AD mice and human postmortem AD brains. An early high cortical expression of SPPL2b was observed, followed by a downregulation in late AD pathology in AppNL-G-F mice, correlating with synaptic loss. To understand the consequences of pathophysiological SPPL2b dysregulation, we found that SPPL2b overexpression significantly increased APP cleavage, while genetic deletion reduced APP cleavage and Aβ production. Notably, postmortem AD brains showed higher levels of SPPL2b's BRI2 substrate compared to healthy control samples. These results strongly support the involvement of SPPL2b in AD pathology. The early Aβ-induced upregulation of SPPL2b may enhance Aβ production in a vicious cycle, further aggravating Aβ pathology. Therefore, SPPL2b emerges as a potential anti-Aβ drug target.
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Affiliation(s)
- Riccardo Maccioni
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, United States.
| | - Caterina Travisan
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; VIB-KU Leuven Center for Brain and Disease Research, Leuven 3001, Belgium.
| | - Jack Badman
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Stefania Zerial
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of life science, University of Trieste, Trieste 34127, Italy.
| | - Annika Wagener
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, 69117 Germany.
| | - Yuniesky Andrade-Talavera
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Federico Picciau
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Biomedical Sciences, Cytomorphology, University of Cagliari, Cagliari 09042, Italy.
| | - Caterina Grassi
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy.
| | - Gefei Chen
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge 141 52, Sweden.
| | - Laetitia Lemoine
- Department of Neurobiology, Care Sciences, and Society, Division of Clinical Geriatrics, Center for Alzheimer Research, Karolinska Institutet, Huddinge 141 52, Sweden.
| | - André Fisahn
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Richeng Jiang
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Otolaryngology Head and Neck Surgery, The First Hospital of Jilin University, Changchun 130021, China.
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, 86159, Germany.
| | - Torben Mentrup
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden 01307, Germany.
| | - Bernd Schröder
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden 01307, Germany.
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Simone Tambaro
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
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3
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Mentrup T, Leinung N, Patel M, Fluhrer R, Schröder B. The role of SPP/SPPL intramembrane proteases in membrane protein homeostasis. FEBS J 2024; 291:25-44. [PMID: 37625440 DOI: 10.1111/febs.16941] [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: 05/24/2023] [Revised: 07/03/2023] [Accepted: 08/23/2023] [Indexed: 08/27/2023]
Abstract
Signal peptide peptidase (SPP) and the four SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 constitute a family of aspartyl intramembrane proteases with homology to presenilins. The different members reside in distinct cellular localisations within the secretory pathway and the endo-lysosomal system. Despite individual cleavage characteristics, they all cleave single-span transmembrane proteins with a type II orientation exhibiting a cytosolic N-terminus. Though the identification of substrates is not complete, SPP/SPPL-mediated proteolysis appears to be rather selective. Therefore, according to our current understanding cleavage by SPP/SPPL proteases rather seems to serve a regulatory function than being a bulk proteolytic pathway. In the present review, we will summarise our state of knowledge on SPP/SPPL proteases and in particular highlight recently identified substrates and the functional and/or (patho)-physiological implications of these cleavage events. Based on this, we aim to provide an overview of the current open questions in the field. These are connected to the regulation of these proteases at the cellular level but also in context of disease and patho-physiological processes. Furthermore, the interplay with other proteostatic systems capable of degrading membrane proteins is beginning to emerge.
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Affiliation(s)
- Torben Mentrup
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
| | - Nadja Leinung
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
| | - Mehul Patel
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Germany
- Center for Interdisciplinary Health Research, University of Augsburg, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
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4
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Höppner S, Schröder B, Fluhrer R. Structure and function of SPP/SPPL proteases: insights from biochemical evidence and predictive modeling. FEBS J 2023; 290:5456-5474. [PMID: 37786993 DOI: 10.1111/febs.16968] [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: 05/30/2023] [Revised: 09/13/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
More than 20 years ago, signal peptide peptidase (SPP) and its homologues, the signal peptide peptidase-like (SPPL) proteases have been identified based on their sequence similarity to presenilins, a related family of intramembrane aspartyl proteases. Other than those for the presenilins, no high-resolution structures for the SPP/SPPL proteases are available. Despite this limitation, over the years bioinformatical and biochemical data have accumulated, which altogether have provided a picture of the overall structure and topology of these proteases, their localization in the cell, the process of substrate recognition, their cleavage mechanism, and their function. Recently, the artificial intelligence-based structure prediction tool AlphaFold has added high-confidence models of the expected fold of SPP/SPPL proteases. In this review, we summarize known structural aspects of the SPP/SPPL family as well as their substrates. Of particular interest are the emerging substrate recognition and catalytic mechanisms that might lead to the prediction and identification of more potential substrates and deeper insight into physiological and pathophysiological roles of proteolysis.
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Affiliation(s)
- Sabine Höppner
- Biochemistry and Molecular Biology, Faculty of Medicine, Institute of Theoretical Medicine, University of Augsburg, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Faculty of Medicine, Institute of Theoretical Medicine, University of Augsburg, Germany
- Center for Interdisciplinary Health Research, University of Augsburg, Germany
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5
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Leinung N, Mentrup T, Patel M, Gallagher T, Schröder B. Dynamic association of the intramembrane proteases SPPL2a/b and their substrates with tetraspanin-enriched microdomains. iScience 2023; 26:107819. [PMID: 37736044 PMCID: PMC10509304 DOI: 10.1016/j.isci.2023.107819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 07/21/2023] [Accepted: 08/31/2023] [Indexed: 09/23/2023] Open
Abstract
Signal peptide peptidase-like 2a and b (SPPL2a/b) are aspartyl intramembrane proteases and cleave tail-anchored proteins as well as N-terminal fragments (NTFs) derived from type II-oriented transmembrane proteins. How these proteases recruit substrates and cleavage is regulated, is still incompletely understood. We found that SPPL2a/b localize to detergent-resistant membrane (DRM) domains with the characteristics of tetraspanin-enriched microdomains (TEMs). Based on this, association with several tetraspanins was evaluated. We demonstrate that not only SPPL2a/b but also their substrates tumor necrosis factor (TNF) and CD74 associate with tetraspanins like CD9, CD81, and CD82 and/or TEMs and analyze the stability of these complexes in different detergents. CD9 and CD81 deficiency has protease- and substrate-selective effects on SPPL2a/b function. Our findings suggest that reciprocal interactions with tetraspanins may assist protease-substrate encounters of SPPL2a/b within the membrane. Beyond SPP/SPPL proteases, this supports previous concepts that tetraspanins facilitate membrane-embedded proteolytic processes.
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Affiliation(s)
- Nadja Leinung
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Mehul Patel
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Tom Gallagher
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Bernd Schröder
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
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6
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Ballin M, Griep W, Patel M, Karl M, Mentrup T, Rivera‐Monroy J, Foo B, Schwappach B, Schröder B. The intramembrane proteases
SPPL2a
and
SPPL2b
regulate the homeostasis of selected
SNARE
proteins. FEBS J 2022; 290:2320-2337. [PMID: 36047592 DOI: 10.1111/febs.16610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 08/30/2022] [Indexed: 01/15/2023]
Abstract
Signal peptide peptidase (SPP) and SPP-like (SPPL) aspartyl intramembrane proteases are known to contribute to sequential processing of type II-oriented membrane proteins referred to as regulated intramembrane proteolysis. The ER-resident family members SPP and SPPL2c were shown to also cleave tail-anchored proteins, including selected SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins facilitating membrane fusion events. Here, we analysed whether the related SPPL2a and SPPL2b proteases, which localise to the endocytic or late secretory pathway, are also able to process SNARE proteins. Therefore, we screened 18 SNARE proteins for cleavage by SPPL2a and SPPL2b based on cellular co-expression assays, of which the proteins VAMP1, VAMP2, VAMP3 and VAMP4 were processed by SPPL2a/b demonstrating the capability of these two proteases to proteolyse tail-anchored proteins. Cleavage of the four SNARE proteins was scrutinised at the endogenous level upon SPPL2a/b inhibition in different cell lines as well as by analysing VAMP1-4 levels in tissues and primary cells of SPPL2a/b double-deficient (dKO) mice. Loss of SPPL2a/b activity resulted in an accumulation of VAMP1-4 in a cell type- and tissue-dependent manner, identifying these proteins as SPPL2a/b substrates validated in vivo. Therefore, we propose that SPPL2a/b control cellular levels of VAMP1-4 by initiating the degradation of these proteins, which might impact cellular trafficking.
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Affiliation(s)
- Moritz Ballin
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Wolfram Griep
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Mehul Patel
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Martin Karl
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Jhon Rivera‐Monroy
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Brian Foo
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Blanche Schwappach
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
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7
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Mentrup T, Stumpff-Niggemann AY, Leinung N, Schlosser C, Schubert K, Wehner R, Tunger A, Schatz V, Neubert P, Gradtke AC, Wolf J, Rose-John S, Saftig P, Dalpke A, Jantsch J, Schmitz M, Fluhrer R, Jacobsen ID, Schröder B. Phagosomal signalling of the C-type lectin receptor Dectin-1 is terminated by intramembrane proteolysis. Nat Commun 2022; 13:1880. [PMID: 35388002 PMCID: PMC8987071 DOI: 10.1038/s41467-022-29474-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/14/2022] [Indexed: 11/23/2022] Open
Abstract
Sensing of pathogens by pattern recognition receptors (PRR) is critical to initiate protective host defence reactions. However, activation of the immune system has to be carefully titrated to avoid tissue damage necessitating mechanisms to control and terminate PRR signalling. Dectin-1 is a PRR for fungal β-glucans on immune cells that is rapidly internalised after ligand-binding. Here, we demonstrate that pathogen recognition by the Dectin-1a isoform results in the formation of a stable receptor fragment devoid of the ligand binding domain. This fragment persists in phagosomal membranes and contributes to signal transduction which is terminated by the intramembrane proteases Signal Peptide Peptidase-like (SPPL) 2a and 2b. Consequently, immune cells lacking SPPL2b demonstrate increased anti-fungal ROS production, killing capacity and cytokine responses. The identified mechanism allows to uncouple the PRR signalling response from delivery of the pathogen to degradative compartments and identifies intramembrane proteases as part of a regulatory circuit to control anti-fungal immune responses. Dectin-1 is a critical component of the innate sensing repertoire which is involved in pattern based recognition of fungal pathogens. Here the authors show that intramembrane proteolysis is involved in the regulation of the antifungal host response by termination of the phagosomal signalling of Dectin-1.
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Affiliation(s)
- Torben Mentrup
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | - Nadja Leinung
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Christine Schlosser
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - Katja Schubert
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - Rebekka Wehner
- Institute of Immunology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany.,German Cancer Consortium (DKTK), Partner Site Dresden, Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Antje Tunger
- Institute of Immunology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany
| | - Valentin Schatz
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, Regensburg, Germany
| | - Patrick Neubert
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, Regensburg, Germany
| | - Ann-Christine Gradtke
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Janina Wolf
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Stefan Rose-John
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alexander Dalpke
- Institute of Medical Microbiology and Virology, University Hospital Carl Gustav Carus, Medical Faculty, Technische Universität Dresden, Dresden, Germany
| | - Jonathan Jantsch
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, Regensburg, Germany
| | - Marc Schmitz
- Institute of Immunology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany.,German Cancer Consortium (DKTK), Partner Site Dresden, Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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8
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Martins F, Santos I, da Cruz E Silva OAB, Tambaro S, Rebelo S. The role of the integral type II transmembrane protein BRI2 in health and disease. Cell Mol Life Sci 2021; 78:6807-6822. [PMID: 34480585 PMCID: PMC11072861 DOI: 10.1007/s00018-021-03932-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/07/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
BRI2 is a type II transmembrane protein ubiquitously expressed whose physiological function remains poorly understood. Although several recent important advances have substantially impacted on our understanding of BRI2 biology and function, providing valuable information for further studies on BRI2. These findings have contributed to a better understanding of BRI2 biology and the underlying signaling pathways involved. In turn, these might provide novel insights with respect to neurodegeneration processes inherent to BRI2-related pathologies, namely Familial British and Danish dementias, Alzheimer's disease, ITM2B-related retinal dystrophy, and multiple sclerosis. In this review, we provided a state-of-the-art outline of BRI2 biology, both in physiological and pathological conditions, and discuss the proposed molecular underlying mechanisms. Overall, the BRI2 knowledge here reviewed is of extreme importance and may contribute to propose BRI2 and/or BRI2 proteolytic fragments as novel therapeutic targets for neurodegenerative diseases, such as Alzheimer's disease.
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Affiliation(s)
- Filipa Martins
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal.
| | - Isabela Santos
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Simone Tambaro
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, 141 83, Huddinge, Sweden.
| | - Sandra Rebelo
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal.
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9
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Mentrup T, Schröder B. Signal peptide peptidase-like 2 proteases: Regulatory switches or proteasome of the membrane? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119163. [PMID: 34673079 DOI: 10.1016/j.bbamcr.2021.119163] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 10/07/2021] [Accepted: 10/11/2021] [Indexed: 12/30/2022]
Abstract
Signal peptide peptidase-like 2 (SPPL) proteases constitute a subfamily of SPP/SPPL intramembrane proteases which are homologues of the presenilins, the catalytic core of the γ-secretase complex. The three SPPL2 proteases SPPL2a, SPPL2b and SPPL2c proteolyse single-span, type II-oriented transmembrane proteins and/or tail-anchored proteins within their hydrophobic transmembrane segments. We review recent progress in defining substrate spectra and in vivo functions of these proteases. Characterisation of the respective knockout mice has implicated SPPL2 proteases in immune cell differentiation and function, prevention of atherosclerotic plaque development and spermatogenesis. Mechanisms how substrates are selected by these enzymes are still incompletely understood. We will discuss current views on how selective SPPL2-mediated cleavage is or whether these proteases may exhibit a generalised role in the turnover of membrane proteins. This has been suggested previously for the mechanistically related γ-secretase for which the term "proteasome of the membrane" has been coined based on its broad substrate spectrum. With regard to individual substrates, potential signalling functions of the resulting cytosolic cleavage fragments remain a controversial aspect. However, it has been clearly shown that SPPL2 proteases can influence cellular signalling and membrane trafficking by controlling levels of their membrane-bound substrate proteins which highlights these enzymes as regulatory switches. Based on this, regulatory mechanisms controlling activity of SPPL2 proteases would need to be postulated, which are just beginning to emerge. These different questions, which are relevant for other families of intramembrane proteases in a similar way, will be critically discussed based on the current state of knowledge.
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Affiliation(s)
- Torben Mentrup
- Institute for Physiological Chemistry, Technische Universität Dresden, Fiedlerstraße 42, D-01307 Dresden, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Technische Universität Dresden, Fiedlerstraße 42, D-01307 Dresden, Germany.
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10
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Gradtke AC, Mentrup T, Lehmann CHK, Cabrera-Cabrera F, Desel C, Okakpu D, Assmann M, Dalpke A, Schaible UE, Dudziak D, Schröder B. Deficiency of the Intramembrane Protease SPPL2a Alters Antimycobacterial Cytokine Responses of Dendritic Cells. THE JOURNAL OF IMMUNOLOGY 2021; 206:164-180. [PMID: 33239420 DOI: 10.4049/jimmunol.2000151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/30/2020] [Indexed: 12/30/2022]
Abstract
Signal peptide peptidase-like 2a (SPPL2a) is an aspartyl intramembrane protease essential for degradation of the invariant chain CD74. In humans, absence of SPPL2a leads to Mendelian susceptibility to mycobacterial disease, which is attributed to a loss of the dendritic cell (DC) subset conventional DC2. In this study, we confirm depletion of conventional DC2 in lymphatic tissues of SPPL2a-/- mice and demonstrate dependence on CD74 using SPPL2a-/- CD74-/- mice. Upon contact with mycobacteria, SPPL2a-/- bone marrow-derived DCs show enhanced secretion of IL-1β, whereas production of IL-10 and IFN-β is reduced. These effects correlated with modulated responses upon selective stimulation of the pattern recognition receptors TLR4 and Dectin-1. In SPPL2a-/- bone marrow-derived DCs, Dectin-1 is redistributed to endosomal compartments. Thus, SPPL2a deficiency alters pattern recognition receptor pathways in a CD74-dependent way, shifting the balance from anti- to proinflammatory cytokines in antimycobacterial responses. We propose that in addition to the DC reduction, this altered DC functionality contributes to Mendelian susceptibility to mycobacterial disease upon SPPL2a deficiency.
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Affiliation(s)
- Ann-Christine Gradtke
- Institute of Physiological Chemistry, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Christian H K Lehmann
- Laboratory of Dendritic Cell Biology, Department of Dermatology, Friedrich-Alexander University Erlangen-Nürnberg, University Hospital Erlangen, D-91052 Erlangen, Germany.,Medical Immunology Campus Erlangen, D-91054 Erlangen, Germany.,Deutsches Zentrum Immuntherapie, D-91054 Erlangen, Germany.,Comprehensive Cancer Center Erlangen-European Metropolitan Area of Nuremberg, D-91054 Erlangen, Germany
| | - Florencia Cabrera-Cabrera
- Institute of Physiological Chemistry, Technische Universität Dresden, D-01307 Dresden, Germany.,Biochemical Institute, Christian-Albrechts-University Kiel, D-24118 Kiel, Germany
| | - Christine Desel
- Biochemical Institute, Christian-Albrechts-University Kiel, D-24118 Kiel, Germany
| | - Darian Okakpu
- Institute of Physiological Chemistry, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Maike Assmann
- Priority Program Infections, Division of Cellular Microbiology, Research Center Borstel, Leibniz Lung Center, and German Center for Infection Research, partner site Borstel, D-23845 Borstel, Germany; and
| | - Alexander Dalpke
- Institute of Medical Microbiology and Hygiene, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Ulrich E Schaible
- Priority Program Infections, Division of Cellular Microbiology, Research Center Borstel, Leibniz Lung Center, and German Center for Infection Research, partner site Borstel, D-23845 Borstel, Germany; and
| | - Diana Dudziak
- Laboratory of Dendritic Cell Biology, Department of Dermatology, Friedrich-Alexander University Erlangen-Nürnberg, University Hospital Erlangen, D-91052 Erlangen, Germany.,Medical Immunology Campus Erlangen, D-91054 Erlangen, Germany.,Deutsches Zentrum Immuntherapie, D-91054 Erlangen, Germany.,Comprehensive Cancer Center Erlangen-European Metropolitan Area of Nuremberg, D-91054 Erlangen, Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry, Technische Universität Dresden, D-01307 Dresden, Germany;
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11
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Papadopoulou AA, Fluhrer R. Signaling Functions of Intramembrane Aspartyl-Proteases. Front Cardiovasc Med 2020; 7:591787. [PMID: 33381526 PMCID: PMC7768045 DOI: 10.3389/fcvm.2020.591787] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/16/2020] [Indexed: 01/18/2023] Open
Abstract
Intramembrane proteolysis is more than a mechanism to "clean" the membranes from proteins no longer needed. By non-reversibly modifying transmembrane proteins, intramembrane cleaving proteases hold key roles in multiple signaling pathways and often distinguish physiological from pathological conditions. Signal peptide peptidase (SPP) and signal peptide peptidase-like proteases (SPPLs) recently have been associated with multiple functions in the field of signal transduction. SPP/SPPLs together with presenilins (PSs) are the only two families of intramembrane cleaving aspartyl proteases known in mammals. PS1 or PS2 comprise the catalytic center of the γ-secretase complex, which is well-studied in the context of Alzheimer's disease. The mammalian SPP/SPPL family of intramembrane cleaving proteases consists of five members: SPP and its homologous proteins SPPL2a, SPPL2b, SPPL2c, and SPPL3. Although these proteases were discovered due to their homology to PSs, it became evident in the past two decades that no physiological functions are shared between these two families. Based on studies in cell culture models various substrates of SPP/SPPL proteases have been identified in the past years and recently-developed mouse lines lacking individual members of this protease family, will help to further clarify the physiological functions of these proteases. In this review we concentrate on signaling roles of mammalian intramembrane cleaving aspartyl proteases. In particular, we will highlight the signaling roles of PS via its substrates NOTCH, VEGF, and others, mainly focusing on its involvement in vasculature. Delineating also signaling pathways that are affected and/or controlled by SPP/SPPL proteases. From SPP's participation in tumor progression and survival, to SPPL3's regulation of protein glycosylation and SPPL2c's control over cellular calcium stores, various crossovers between proteolytic activity of intramembrane proteases and cell signaling will be described.
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Affiliation(s)
- Alkmini A. Papadopoulou
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
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12
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Signal Peptide Peptidase-Type Proteases: Versatile Regulators with Functions Ranging from Limited Proteolysis to Protein Degradation. J Mol Biol 2020; 432:5063-5078. [DOI: 10.1016/j.jmb.2020.05.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/02/2020] [Accepted: 05/19/2020] [Indexed: 12/15/2022]
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13
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Mentrup T, Cabrera-Cabrera F, Fluhrer R, Schröder B. Physiological functions of SPP/SPPL intramembrane proteases. Cell Mol Life Sci 2020; 77:2959-2979. [PMID: 32052089 PMCID: PMC7366577 DOI: 10.1007/s00018-020-03470-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/22/2020] [Indexed: 01/07/2023]
Abstract
Intramembrane proteolysis describes the cleavage of substrate proteins within their hydrophobic transmembrane segments. Several families of intramembrane proteases have been identified including the aspartyl proteases Signal peptide peptidase (SPP) and its homologues, the SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and SPPL3. As presenilin homologues, they employ a similar catalytic mechanism as the well-studied γ-secretase. However, SPP/SPPL proteases cleave transmembrane proteins with a type II topology. The characterisation of SPP/SPPL-deficient mouse models has highlighted a still growing spectrum of biological functions and also promoted the substrate discovery of these proteases. In this review, we will summarise the current hypotheses how phenotypes of these mouse models are linked to the molecular function of the enzymes. At the cellular level, SPP/SPPL-mediated cleavage events rather provide specific regulatory switches than unspecific bulk proteolysis. By this means, a plethora of different cell biological pathways is influenced including signal transduction, membrane trafficking and protein glycosylation.
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Affiliation(s)
- Torben Mentrup
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany
| | - Florencia Cabrera-Cabrera
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Faculty of Medicine, University of Augsburg, Universitätsstraße 2, 86135, Augsburg, Germany
- Biomedizinisches Centrum (BMC), Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 17, 81377, Munich, Germany
- DZNE-German Center for Neurodegenerative Diseases, Munich, Feodor-Lynen-Strasse 17, 81377, Munich, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany.
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14
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van Kempen TS, Leijten EFA, Lindenbergh MFS, Nordkamp MO, Driessen C, Lebbink RJ, Baerlecken N, Witte T, Radstake TRDJ, Boes M. Impaired proteolysis by SPPL2a causes CD74 fragment accumulation that can be recognized by anti-CD74 autoantibodies in human ankylosing spondylitis. Eur J Immunol 2020; 50:1209-1219. [PMID: 32198923 PMCID: PMC7496470 DOI: 10.1002/eji.201948502] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/10/2020] [Indexed: 12/14/2022]
Abstract
Ankylosing spondylitis (AS) is associated with autoantibody production to class II MHC‐associated invariant chain peptide, CD74/CLIP. In this study, we considered that anti‐CD74/CLIP autoantibodies present in sera from AS might recognize CD74 degradation products that accumulate upon deficiency of the enzyme signal peptide peptidase‐like 2A (SPPL2a). We analyzed monocytes from healthy controls (n = 42), psoriatic arthritis (n = 25), rheumatoid arthritis (n = 16), and AS patients (n = 15) for SPPL2a enzyme activity and complemented the experiments using SPPL2a‐sufficient and ‐deficient THP‐1 cells. We found defects in SPPL2a function and CD74 processing in a subset of AS patients, which culminated in CD74 and HLA class II display at the cell surface. These findings were verified in SPPL2a‐deficient THP‐1 cells, which showed expedited expression of MHC class II, total CD74 and CD74 N‐terminal degradation products at the plasma membrane upon receipt of an inflammatory trigger. Furthermore, we observed that IgG anti‐CD74/CLIP autoantibodies recognize CD74 N‐terminal degradation products that accumulate upon SPPL2a defect. In conclusion, reduced activity of SPPL2a protease in monocytes from AS predisposes to endosomal accumulation of CD74 and CD74 N‐terminal fragments, which, upon IFN‐γ‐exposure, is deposited at the plasma membrane and can be recognized by anti‐CD74/CLIP autoantibodies.
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Affiliation(s)
- Tessa S van Kempen
- Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emmerik F A Leijten
- Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marthe F S Lindenbergh
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Michel Olde Nordkamp
- Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Christoph Driessen
- Department of Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Robert-Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Niklas Baerlecken
- Department of Clinical Immunology and Rheumatology, Medical University Hannover, Hannover, Germany
| | - Torsten Witte
- Department of Clinical Immunology and Rheumatology, Medical University Hannover, Hannover, Germany
| | - Timothy R D J Radstake
- Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne Boes
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Pediatrics, University Medical Center Utrecht, Utrecht, the Netherlands
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15
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Niemeyer J, Mentrup T, Heidasch R, Müller SA, Biswas U, Meyer R, Papadopoulou AA, Dederer V, Haug-Kröper M, Adamski V, Lüllmann-Rauch R, Bergmann M, Mayerhofer A, Saftig P, Wennemuth G, Jessberger R, Fluhrer R, Lichtenthaler SF, Lemberg MK, Schröder B. The intramembrane protease SPPL2c promotes male germ cell development by cleaving phospholamban. EMBO Rep 2019; 20:e46449. [PMID: 30733280 PMCID: PMC6399600 DOI: 10.15252/embr.201846449] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 11/09/2022] Open
Abstract
Signal peptide peptidase (SPP) and the four homologous SPP-like (SPPL) proteases constitute a family of intramembrane aspartyl proteases with selectivity for type II-oriented transmembrane segments. Here, we analyse the physiological function of the orphan protease SPPL2c, previously considered to represent a non-expressed pseudogene. We demonstrate proteolytic activity of SPPL2c towards selected tail-anchored proteins. Despite shared ER localisation, SPPL2c and SPP exhibit distinct, though partially overlapping substrate spectra and inhibitory profiles, and are organised in different high molecular weight complexes. Interestingly, SPPL2c is specifically expressed in murine and human testis where it is primarily localised in spermatids. In mice, SPPL2c deficiency leads to a partial loss of elongated spermatids and reduced motility of mature spermatozoa, but preserved fertility. However, matings of male and female SPPL2c-/- mice exhibit reduced litter sizes. Using proteomics we identify the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2)-regulating protein phospholamban (PLN) as a physiological SPPL2c substrate. Accumulation of PLN correlates with a decrease in intracellular Ca2+ levels in elongated spermatids that likely contribute to the compromised male germ cell differentiation and function of SPPL2c-/- mice.
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Affiliation(s)
- Johannes Niemeyer
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Torben Mentrup
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Ronny Heidasch
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Stephan A Müller
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar and Institute for Advanced Study, Technical University of Munich, Munich, Germany
| | - Uddipta Biswas
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Rieke Meyer
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alkmini A Papadopoulou
- Institute for Metabolic Biochemistry, Biomedical Center (BMC) München, Ludwig Maximilians University of Munich, Munich, Germany
| | - Verena Dederer
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Martina Haug-Kröper
- Institute for Metabolic Biochemistry, Biomedical Center (BMC) München, Ludwig Maximilians University of Munich, Munich, Germany
| | - Vivian Adamski
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | | | - Martin Bergmann
- Institute of Veterinary Anatomy, Justus Liebig University of Gießen, Gießen, Germany
| | - Artur Mayerhofer
- Cell Biology, Anatomy III, Biomedical Center (BMC) München, Ludwig Maximilians University of Munich, Munich, Germany
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Gunther Wennemuth
- Institute of Anatomy, University Hospital, Duisburg-Essen University, Essen, Germany
| | - Rolf Jessberger
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Regina Fluhrer
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Institute for Metabolic Biochemistry, Biomedical Center (BMC) München, Ludwig Maximilians University of Munich, Munich, Germany
| | - Stefan F Lichtenthaler
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar and Institute for Advanced Study, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Marius K Lemberg
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
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16
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Mentrup T, Theodorou K, Cabrera-Cabrera F, Helbig AO, Happ K, Gijbels M, Gradtke AC, Rabe B, Fukumori A, Steiner H, Tholey A, Fluhrer R, Donners M, Schröder B. Atherogenic LOX-1 signaling is controlled by SPPL2-mediated intramembrane proteolysis. J Exp Med 2019; 216:807-830. [PMID: 30819724 PMCID: PMC6446863 DOI: 10.1084/jem.20171438] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 08/21/2018] [Accepted: 10/17/2018] [Indexed: 11/27/2022] Open
Abstract
The intramembrane proteases SPPL2a/b control pro-atherogenic signaling of membrane-bound proteolytic fragments derived from the oxLDL receptor LOX-1. In mice deficient for these proteases, plaque development and fibrosis is enhanced. This highlights SPPL2a/b as crucial players of a novel athero-protective mechanism, which is conserved in humans. The lectin-like oxidized LDL receptor 1 (LOX-1) is a key player in the development of atherosclerosis. LOX-1 promotes endothelial activation and dysfunction by mediating uptake of oxidized LDL and inducing pro-atherogenic signaling. However, little is known about modulators of LOX-1–mediated responses. Here, we show that the function of LOX-1 is controlled proteolytically. Ectodomain shedding by the metalloprotease ADAM10 and lysosomal degradation generate membrane-bound N-terminal fragments (NTFs), which we identified as novel substrates of the intramembrane proteases signal peptide peptidase–like 2a and b (SPPL2a/b). SPPL2a/b control cellular LOX-1 NTF levels which, following self-association via their transmembrane domain, can activate MAP kinases in a ligand-independent manner. This leads to an up-regulation of several pro-atherogenic and pro-fibrotic targets including ICAM-1 and the connective tissue growth factor CTGF. Consequently, SPPL2a/b-deficient mice, which accumulate LOX-1 NTFs, develop larger and more advanced atherosclerotic plaques than controls. This identifies intramembrane proteolysis by SPPL2a/b as a novel atheroprotective mechanism via negative regulation of LOX-1 signaling.
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Affiliation(s)
- Torben Mentrup
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany.,Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Kosta Theodorou
- Department of Pathology, Cardiovascular Research Institute, Maastricht University, Maastricht, Netherlands
| | - Florencia Cabrera-Cabrera
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany.,Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Andreas O Helbig
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Christian Albrechts University of Kiel, Kiel, Germany
| | - Kathrin Happ
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Marion Gijbels
- Department of Pathology, Cardiovascular Research Institute, Maastricht University, Maastricht, Netherlands.,Department of Molecular Genetics, Cardiovascular Research Institute, Maastricht University, Maastricht, Netherlands.,Amsterdam Cardiovascular Sciences, Department of Medical Biochemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Ann-Christine Gradtke
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany.,Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Björn Rabe
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Akio Fukumori
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Biomedical Center, Metabolic Biochemistry, Ludwig Maximilians University of Munich, Munich, Germany
| | - Andreas Tholey
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Christian Albrechts University of Kiel, Kiel, Germany
| | - Regina Fluhrer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Biomedical Center, Metabolic Biochemistry, Ludwig Maximilians University of Munich, Munich, Germany
| | - Marjo Donners
- Department of Pathology, Cardiovascular Research Institute, Maastricht University, Maastricht, Netherlands
| | - Bernd Schröder
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany .,Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
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17
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Kong XF, Martinez-Barricarte R, Kennedy J, Mele F, Lazarov T, Deenick EK, Ma CS, Breton G, Lucero KB, Langlais D, Bousfiha A, Aytekin C, Markle J, Trouillet C, Jabot-Hanin F, Arlehamn CSL, Rao G, Picard C, Lasseau T, Latorre D, Hambleton S, Deswarte C, Itan Y, Abarca K, Moraes-Vasconcelos D, Ailal F, Ikinciogullari A, Dogu F, Benhsaien I, Sette A, Abel L, Boisson-Dupuis S, Schröder B, Nussenzweig MC, Liu K, Geissmann F, Tangye SG, Gros P, Sallusto F, Bustamante J, Casanova JL. Disruption of an antimycobacterial circuit between dendritic and helper T cells in human SPPL2a deficiency. Nat Immunol 2018; 19:973-985. [PMID: 30127434 PMCID: PMC6130844 DOI: 10.1038/s41590-018-0178-z] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 07/02/2018] [Indexed: 12/21/2022]
Abstract
Human inborn errors of IFN-γ immunity underlie mycobacterial diseases. We describe patients with Mycobacterium bovis (BCG) disease who are homozygous for loss-of-function mutations of SPPL2A. This gene encodes a transmembrane protease that degrades the N-terminal fragment (NTF) of CD74 (HLA invariant chain) in antigen-presenting cells. The CD74 NTF therefore accumulates in the HLA class II+ myeloid and lymphoid cells of SPPL2a-deficient patients. This toxic fragment selectively depletes IL-12- and IL-23-producing CD1c+ conventional dendritic cells (cDC2s) and their circulating progenitors. Moreover, SPPL2a-deficient memory TH1* cells selectively fail to produce IFN-γ when stimulated with mycobacterial antigens in vitro. Finally, Sppl2a-/- mice lack cDC2s, have CD4+ T cells that produce small amounts of IFN-γ after BCG infection, and are highly susceptible to infection with BCG or Mycobacterium tuberculosis. These findings suggest that inherited SPPL2a deficiency in humans underlies mycobacterial disease by decreasing the numbers of cDC2s and impairing IFN-γ production by mycobacterium-specific memory TH1* cells.
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Affiliation(s)
- Xiao-Fei Kong
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
| | - Ruben Martinez-Barricarte
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
| | - James Kennedy
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Federico Mele
- Center of Medical Immunology, Institute for Research in Biomedicine, Faculty of Biomedical Sciences, University of Italian Switzerland, Bellinzona, Switzerland
| | - Tomi Lazarov
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York , NY, USA
| | - Elissa K Deenick
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Cindy S Ma
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Gaëlle Breton
- Laboratory of Molecular Immunology, The Rockefeller University, New York , NY, USA
| | - Kimberly B Lucero
- Department of Microbiology and Immunology, Columbia University Medical Center, New York , NY, USA
| | - David Langlais
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Aziz Bousfiha
- Laboratory of Clinical Immunology, Inflammation and Allergy, Faculty of Medicine and Pharmacy of Casablanca, King Hassan II University, Casablanca, Morocco
- Clinical Immunology Unit, Department of Pediatric Infectious Diseases, Children's Hospital, CHU Averroes, Casablanca, Morocco
| | - Caner Aytekin
- Department of Pediatric Immunology, Dr. Sami Ulus Maternity and Children's Health and Diseases Training and Research Hospital, Ankara, Turkey
| | - Janet Markle
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
| | - Céline Trouillet
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York , NY, USA
| | - Fabienne Jabot-Hanin
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France
- Paris Descartes University, Imagine Institute, Paris, France
| | | | - Geetha Rao
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Capucine Picard
- Paris Descartes University, Imagine Institute, Paris, France
- Study Center for Immunodeficiencies, Necker Hospital for Sick Children, AP-HP, Paris, France
- Pediatric Hematology and Immunology Unit, Necker Hospital for Sick Children, AP-HP, Paris, France
| | - Théo Lasseau
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
| | - Daniela Latorre
- Center of Medical Immunology, Institute for Research in Biomedicine, Faculty of Biomedical Sciences, University of Italian Switzerland, Bellinzona, Switzerland
| | - Sophie Hambleton
- Primary Immunodeficiency Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Caroline Deswarte
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France
- Paris Descartes University, Imagine Institute, Paris, France
| | - Yuval Itan
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
| | - Katia Abarca
- Department of Pediatric Infectious Diseases and Immunology, Millennium Institute of Immunology and Immunotherapy, School of Medicine, Pontifical Catholic University of Chile, Santiago, Chile
| | - Dewton Moraes-Vasconcelos
- Laboratory of Investigation in Dermatology and Immunodeficiencies, University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Fatima Ailal
- Laboratory of Clinical Immunology, Inflammation and Allergy, Faculty of Medicine and Pharmacy of Casablanca, King Hassan II University, Casablanca, Morocco
- Clinical Immunology Unit, Department of Pediatric Infectious Diseases, Children's Hospital, CHU Averroes, Casablanca, Morocco
| | - Aydan Ikinciogullari
- Department of Pediatric Immunology and Allergy, Ankara University School of Medicine, Ankara, Turkey
| | - Figen Dogu
- Department of Pediatric Immunology and Allergy, Ankara University School of Medicine, Ankara, Turkey
| | - Ibtihal Benhsaien
- Laboratory of Clinical Immunology, Inflammation and Allergy, Faculty of Medicine and Pharmacy of Casablanca, King Hassan II University, Casablanca, Morocco
- Clinical Immunology Unit, Department of Pediatric Infectious Diseases, Children's Hospital, CHU Averroes, Casablanca, Morocco
| | - Alessandro Sette
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Laurent Abel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France
- Paris Descartes University, Imagine Institute, Paris, France
| | - Stéphanie Boisson-Dupuis
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France
- Paris Descartes University, Imagine Institute, Paris, France
| | - Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
- Institute of Physiological Chemistry, Technical University Dresden, Dresden, Germany
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York , NY, USA
- Howard Hughes Medical Institute, New York, NY, USA
| | - Kang Liu
- Department of Microbiology and Immunology, Columbia University Medical Center, New York , NY, USA
| | - Frédéric Geissmann
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York , NY, USA
| | - Stuart G Tangye
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Philippe Gros
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Federica Sallusto
- Center of Medical Immunology, Institute for Research in Biomedicine, Faculty of Biomedical Sciences, University of Italian Switzerland, Bellinzona, Switzerland
- Institute of Microbiology, ETH Zurich, Zürich, Switzerland
| | - Jacinta Bustamante
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France
- Paris Descartes University, Imagine Institute, Paris, France
- Study Center for Immunodeficiencies, Necker Hospital for Sick Children, AP-HP, Paris, France
| | - Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York , NY, USA.
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.
- Paris Descartes University, Imagine Institute, Paris, France.
- Pediatric Hematology and Immunology Unit, Necker Hospital for Sick Children, AP-HP, Paris, France.
- Howard Hughes Medical Institute, New York, NY, USA.
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18
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Langosch D, Steiner H. Substrate processing in intramembrane proteolysis by γ-secretase - the role of protein dynamics. Biol Chem 2017; 398:441-453. [PMID: 27845877 DOI: 10.1515/hsz-2016-0269] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/08/2016] [Indexed: 01/31/2023]
Abstract
Intramembrane proteases comprise a number of different membrane proteins with different types of catalytic sites. Their common denominator is cleavage within the plane of the membrane, which usually results in peptide bond scission within the transmembrane helices of their substrates. Despite recent progress in the determination of high-resolution structures, as illustrated here for the γ-secretase complex and its substrate C99, it is still unknown how these enzymes function and how they distinguish between substrates and non-substrates. In principle, substrate/non-substrate discrimination could occur at the level of substrate binding and/or cleavage. Focusing on the γ-secretase/C99 pair, we will discuss recent observations suggesting that global motions within a substrate transmembrane helix may be much more important for defining a substrate than local unraveling at cleavage sites.
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19
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Mentrup T, Fluhrer R, Schröder B. Latest emerging functions of SPP/SPPL intramembrane proteases. Eur J Cell Biol 2017; 96:372-382. [DOI: 10.1016/j.ejcb.2017.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022] Open
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20
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Signal peptide peptidase and SPP-like proteases - Possible therapeutic targets? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017. [PMID: 28624439 DOI: 10.1016/j.bbamcr.2017.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Signal peptide peptidase (SPP) and the four homologous SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 are GxGD-type intramembrane-cleaving proteases (I-CLIPs). In addition to divergent subcellular localisations, distinct differences in the mechanistic properties and substrate requirements of individual family members have been unravelled. SPP/SPPL proteases employ a catalytic mechanism related to that of the γ-secretase complex. Nevertheless, differential targeting of SPP/SPPL proteases and γ-secretase by inhibitors has been demonstrated. Furthermore, also within the SPP/SPPL family significant differences in the sensitivity to currently available inhibitory compounds have been reported. Though far from complete, our knowledge on pathophysiological functions of SPP/SPPL proteases, in particular based on studies in mice, has been significantly increased over the last years. Based on this, inhibition of distinct SPP/SPPL proteases has been proposed as a novel therapeutic concept e.g. for the treatment of autoimmunity and viral or protozoal infections, as we will discuss in this review. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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21
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Schneppenheim J, Loock AC, Hüttl S, Schweizer M, Lüllmann-Rauch R, Oberg HH, Arnold P, Lehmann CHK, Dudziak D, Kabelitz D, Lucius R, Lennon-Duménil AM, Saftig P, Schröder B. The Influence of MHC Class II on B Cell Defects Induced by Invariant Chain/CD74 N-Terminal Fragments. THE JOURNAL OF IMMUNOLOGY 2017; 199:172-185. [DOI: 10.4049/jimmunol.1601533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 05/01/2017] [Indexed: 01/24/2023]
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22
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Schröder B, Saftig P. Intramembrane proteolysis within lysosomes. Ageing Res Rev 2016; 32:51-64. [PMID: 27143694 DOI: 10.1016/j.arr.2016.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/01/2016] [Accepted: 04/26/2016] [Indexed: 11/26/2022]
Abstract
Regulated intramembrane proteolysis is of pivotal importance in a diverse set of developmental and physiological processes. Altered intramembrane substrate turnover may be associated with neurodegeneration, cancer and impaired immune function. In this review we will focus on the intramembrane proteases which have been localized in the lysosomal membrane. Members of the γ-secretase complex and γ-secretase activity are found in the lysosomal membrane and are discussed to contribute to intracellular amyloid β production. Mutant or deficient γ-secretase may cause disturbed lysosomal function. The signal peptide peptidase-like (SPPL) protease 2a is a lysosomal membrane component and cleaves CD74, the invariant chain of the MHC II complex, as well as FasL, TNF, ITM2B and TMEM106, type II transmembrane proteins involved in the regulation of immunity and neurodegeneration. Therefore, it can be concluded, that not only proteolysis within the lysosomal lumen but also within lysosomal membranes regulates important cellular functions and contributes essentially to proteostasis of membrane proteins what may become increasingly compromised in the aged individual.
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23
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The biological function and significance of CD74 in immune diseases. Inflamm Res 2016; 66:209-216. [DOI: 10.1007/s00011-016-0995-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/30/2016] [Indexed: 12/25/2022] Open
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24
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Substrate determinants of signal peptide peptidase-like 2a (SPPL2a)-mediated intramembrane proteolysis of the invariant chain CD74. Biochem J 2016; 473:1405-22. [DOI: 10.1042/bcj20160156] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/16/2016] [Indexed: 11/17/2022]
Abstract
Intramembrane proteolysis of CD74 by SPPL2a is essential for B- and dendritic cells. We show that CD74 is proteolysed in the luminal third of the transmembrane segment and identify determinants within its transmembrane and luminal membrane-proximal domain facilitating this cleavage.
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25
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Schröder B. The multifaceted roles of the invariant chain CD74--More than just a chaperone. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1269-81. [PMID: 27033518 DOI: 10.1016/j.bbamcr.2016.03.026] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/13/2023]
Abstract
The invariant chain (CD74) is well known for its essential role in antigen presentation by mediating assembly and subcellular trafficking of the MHCII complex. Beyond this, CD74 has also been implicated in a number of processes independent of MHCII. These include the regulation of endosomal trafficking, cell migration and cellular signalling as surface receptor of the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF). In several forms of cancer, CD74 is up-regulated and associated with enhanced proliferation and metastatic potential. In this review, an overview of the diverse biological functions of the CD74 protein is provided with a particular focus on how these may be regulated. In particular, proteolysis of CD74 will be discussed as a central mechanism to control the actions of this important protein at different levels.
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Affiliation(s)
- Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, Otto-Hahn-Platz 9, D-24118 Kiel, Germany.
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26
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Hüttl S, Kläsener K, Schweizer M, Schneppenheim J, Oberg HH, Kabelitz D, Reth M, Saftig P, Schröder B. Processing of CD74 by the Intramembrane Protease SPPL2a Is Critical for B Cell Receptor Signaling in Transitional B Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:1548-63. [PMID: 26157172 DOI: 10.4049/jimmunol.1403171] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/09/2015] [Indexed: 12/16/2022]
Abstract
The invariant chain (CD74), a chaperone in MHC class II-mediated Ag presentation, is sequentially processed by different endosomal proteases. We reported recently that clearance of the final membrane-bound N-terminal fragment (NTF) of CD74 is mediated by the intramembrane protease signal peptide peptidase-like (SPPL)2a, a process critical for B cell development. In mice, SPPL2a deficiency provokes the accumulation of this NTF in endocytic vesicles, which leads to a B cell maturation arrest at the transitional 1 stage. To define the underlying mechanism, we analyzed the impact of SPPL2a deficiency on signaling pathways involved in B cell homeostasis. We demonstrate that tonic as well as BCR-induced activation of the PI3K/Akt pathway is massively compromised in SPPL2a(-/-) B cells and identify this as major cause of the B cell maturation defect in these mice. Altered BCR trafficking induces a reduction of surface IgM in SPPL2a-deficient B cells, leading to a diminished signal transmission via the BCR and the tyrosine kinase Syk. We provide evidence that in SPPL2a(-/-) mice impaired BCR signaling is to a great extent provoked by the accumulating CD74 NTF, which can interact with the BCR and Syk, and that impaired PI3K/Akt signaling and reduced surface IgM are not directly linked processes. In line with disturbances in PI3K/Akt signaling, SPPL2a(-/-) B cells show a dysregulation of the transcription factor FOXO1, causing elevated transcription of proapoptotic genes. We conclude that SPPL2a-mediated processing of CD74 NTF is indispensable to maintain appropriate levels of tonic BCR signaling to promote B cell maturation.
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Affiliation(s)
- Susann Hüttl
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Kathrin Kläsener
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Janna Schneppenheim
- Institute of Anatomy, Christian Albrechts University of Kiel, D-24118 Kiel, Germany; and
| | - Hans-Heinrich Oberg
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Dieter Kabelitz
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany;
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27
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Ran Y, Ladd GZ, Ceballos-Diaz C, Jung JI, Greenbaum D, Felsenstein KM, Golde TE. Differential Inhibition of Signal Peptide Peptidase Family Members by Established γ-Secretase Inhibitors. PLoS One 2015; 10:e0128619. [PMID: 26046535 PMCID: PMC4457840 DOI: 10.1371/journal.pone.0128619] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/29/2015] [Indexed: 11/19/2022] Open
Abstract
The signal peptide peptidases (SPPs) are biomedically important proteases implicated as therapeutic targets for hepatitis C (human SPP, (hSPP)), plasmodium (Plasmodium SPP (pSPP)), and B-cell immunomodulation and neoplasia (signal peptide peptidase like 2a, (SPPL2a)). To date, no drug-like, selective inhibitors have been reported. We use a recombinant substrate based on the amino-terminus of BRI2 fused to amyloid β 1-25 (Aβ1-25) (FBA) to develop facile, cost-effective SPP/SPPL protease assays. Co-transfection of expression plasmids expressing the FBA substrate with SPP/SPPLs were conducted to evaluate cleavage, which was monitored by ELISA, Western Blot and immunoprecipitation/MALDI-TOF Mass spectrometry (IP/MS). No cleavage is detected in the absence of SPP/SPPL overexpression. Multiple γ-secretase inhibitors (GSIs) and (Z-LL)2 ketone differentially inhibited SPP/SPPL activity; for example, IC50 of LY-411,575 varied from 51±79 nM (on SPPL2a) to 5499±122 nM (on SPPL2b), while Compound E showed inhibition only on hSPP with IC50 of 1465±93 nM. Data generated were predictive of effects observed for endogenous SPPL2a cleavage of CD74 in a murine B-Cell line. Thus, it is possible to differentially inhibit SPP family members. These SPP/SPPL cleavage assays will expedite the search for selective inhibitors. The data also reinforce similarities between SPP family member cleavage and cleavage catalyzed by γ-secretase.
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Affiliation(s)
- Yong Ran
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
- * E-mail: (YR); (TG)
| | - Gabriela Z. Ladd
- College of Pharmacy, University of Florida, Gainesville, Florida, United States of America
| | - Carolina Ceballos-Diaz
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Joo In Jung
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Doron Greenbaum
- Pennsylvania Drug Discovery Institute, Philadelphia, Pennsylvania, United States of America
| | - Kevin M. Felsenstein
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Todd E. Golde
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
- * E-mail: (YR); (TG)
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28
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Mentrup T, Häsler R, Fluhrer R, Saftig P, Schröder B. A Cell-Based Assay Reveals Nuclear Translocation of Intracellular Domains Released by SPPL Proteases. Traffic 2015; 16:871-92. [DOI: 10.1111/tra.12287] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/26/2015] [Accepted: 03/26/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Torben Mentrup
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Robert Häsler
- Institute of Clinical Molecular Biology; Christian Albrechts University of Kiel; Schittenhelmstr. 12 D-24105 Kiel Germany
| | - Regina Fluhrer
- Biomedizinisches Centrum (BMC); Ludwig Maximilians University of Munich; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
- DZNE - German Center for Neurodegenerative Diseases; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
| | - Paul Saftig
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Bernd Schröder
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
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29
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Videm P, Gunasekaran D, Schröder B, Mayer B, Biniossek ML, Schilling O. Automated peptide mapping and protein-topographical annotation of proteomics data. BMC Bioinformatics 2014; 15:207. [PMID: 24946880 PMCID: PMC4071796 DOI: 10.1186/1471-2105-15-207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/18/2014] [Indexed: 12/03/2022] Open
Abstract
Background In quantitative proteomics, peptide mapping is a valuable approach to combine positional quantitative information with topographical and domain information of proteins. Quantitative proteomic analysis of cell surface shedding is an exemplary application area of this approach. Results We developed ImproViser (
http://www.improviser.uni-freiburg.de) for fully automated peptide mapping of quantitative proteomics data in the protXML data. The tool generates sortable and graphically annotated output, which can be easily shared with further users. As an exemplary application, we show its usage in the proteomic analysis of regulated intramembrane proteolysis. Conclusion ImproViser is the first tool to enable automated peptide mapping of the widely-used protXML format.
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Affiliation(s)
| | | | | | | | | | - Oliver Schilling
- Institute of Molecular Medicine and Cell Research, University of Freiburg, D-79104 Freiburg, Germany.
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30
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Brady OA, Zhou X, Hu F. Regulated intramembrane proteolysis of the frontotemporal lobar degeneration risk factor, TMEM106B, by signal peptide peptidase-like 2a (SPPL2a). J Biol Chem 2014; 289:19670-80. [PMID: 24872421 DOI: 10.1074/jbc.m113.515700] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The sequential processing of single pass transmembrane proteins via ectodomain shedding followed by intramembrane proteolysis is involved in a wide variety of signaling processes, as well as maintenance of membrane protein homeostasis. Here we report that the recently identified frontotemporal lobar degeneration risk factor TMEM106B undergoes regulated intramembrane proteolysis. We demonstrate that TMEM106B is readily processed to an N-terminal fragment containing the transmembrane and intracellular domains, and this processing is dependent on the activities of lysosomal proteases. The N-terminal fragment is further processed into a small, rapidly degraded intracellular domain. The GxGD aspartyl proteases SPPL2a and, to a lesser extent, SPPL2b are responsible for this intramembrane cleavage event. Additionally, the TMEM106B paralog TMEM106A is also lysosomally localized; however, it is not a specific substrate of SPPL2a or SPPL2b. Our data add to the growing list of proteins that undergo intramembrane proteolysis and may shed light on the regulation of the frontotemporal lobar degeneration risk factor TMEM106B.
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Affiliation(s)
- Owen A Brady
- From the Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853
| | - Xiaolai Zhou
- From the Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853
| | - Fenghua Hu
- From the Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853
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