1
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Voss M. Proteolytic cleavage of Golgi glycosyltransferases by SPPL3 and other proteases and its implications for cellular glycosylation. Biochim Biophys Acta Gen Subj 2024; 1868:130668. [PMID: 38992482 DOI: 10.1016/j.bbagen.2024.130668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/13/2024]
Abstract
Glycosylation of proteins and lipids is of fundamental importance in multicellular eukaryotes. The vast diversity of glycan structures observed is generated in the Golgi apparatus by the concerted activity of >100 distinct enzymes, which include glycosyltransferases and other glycan-modifying enzymes. Well-known for decades, the majority of these enzymes is released from the Golgi apparatus and subsequently secreted into the extracellular space following endoproteolytic cleavage, but the underlying molecular mechanisms and the physiological implications have remained unexplored. This review will summarize our current knowledge of Golgi enzyme proteolysis and secretion and will discuss its conceptual implications for the regulation of cellular glycosylation and the organization of the Golgi apparatus. A particular focus will lie on the intramembrane protease SPPL3, which recently emerged as key protease facilitating Golgi enzyme release and has since been shown to affect a multitude of glycosylation-dependent physiological processes.
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Affiliation(s)
- Matthias Voss
- Institute of Biochemistry, Kiel University, Kiel, Germany.
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2
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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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3
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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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4
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Papadopoulou AA, Stelzer W, Silber M, Schlosser C, Spitz C, Haug-Kröper M, Straub T, Müller SA, Lichtenthaler SF, Muhle-Goll C, Langosch D, Fluhrer R. Helical stability of the GnTV transmembrane domain impacts on SPPL3 dependent cleavage. Sci Rep 2022; 12:20987. [PMID: 36470941 PMCID: PMC9722940 DOI: 10.1038/s41598-022-24772-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Signal-Peptide Peptidase Like-3 (SPPL3) is an intramembrane cleaving aspartyl protease that causes secretion of extracellular domains from type-II transmembrane proteins. Numerous Golgi-localized glycosidases and glucosyltransferases have been identified as physiological SPPL3 substrates. By SPPL3 dependent processing, glycan-transferring enzymes are deactivated inside the cell, as their active site-containing domain is cleaved and secreted. Thus, SPPL3 impacts on glycan patterns of many cellular and secreted proteins and can regulate protein glycosylation. However, the characteristics that make a substrate a favourable candidate for SPPL3-dependent cleavage remain unknown. To gain insights into substrate requirements, we investigated the function of a GxxxG motif located in the transmembrane domain of N-acetylglucosaminyltransferase V (GnTV), a well-known SPPL3 substrate. SPPL3-dependent secretion of the substrate's ectodomain was affected by mutations disrupting the GxxxG motif. Using deuterium/hydrogen exchange and NMR spectroscopy, we studied the effect of these mutations on the helix flexibility of the GnTV transmembrane domain and observed that increased flexibility facilitates SPPL3-dependent shedding and vice versa. This study provides first insights into the characteristics of SPPL3 substrates, combining molecular biology, biochemistry, and biophysical techniques and its results will provide the basis for better understanding the characteristics of SPPL3 substrates with implications for the substrates of other intramembrane proteases.
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Affiliation(s)
- Alkmini A. Papadopoulou
- grid.7307.30000 0001 2108 9006Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätstrasse 2, 86159 Augsburg, Germany
| | - Walter Stelzer
- grid.6936.a0000000123222966Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Mara Silber
- grid.7892.40000 0001 0075 5874Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany ,grid.7892.40000 0001 0075 5874Institute of Organic Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Christine Schlosser
- grid.7307.30000 0001 2108 9006Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätstrasse 2, 86159 Augsburg, Germany
| | - Charlotte Spitz
- grid.7307.30000 0001 2108 9006Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätstrasse 2, 86159 Augsburg, Germany
| | - Martina Haug-Kröper
- grid.7307.30000 0001 2108 9006Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätstrasse 2, 86159 Augsburg, Germany
| | - Tobias Straub
- grid.5252.00000 0004 1936 973XCore Facility Bioinformatics, Biomedical Center, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Stephan A. Müller
- grid.424247.30000 0004 0438 0426DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
| | - Stefan F. Lichtenthaler
- grid.424247.30000 0004 0438 0426DZNE – German Center for Neurodegenerative Diseases, Munich, Germany ,grid.15474.330000 0004 0477 2438Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany ,grid.452617.3Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Claudia Muhle-Goll
- grid.7892.40000 0001 0075 5874Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany ,grid.7892.40000 0001 0075 5874Institute of Organic Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Dieter Langosch
- grid.6936.a0000000123222966Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Regina Fluhrer
- grid.7307.30000 0001 2108 9006Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätstrasse 2, 86159 Augsburg, Germany
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5
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Truberg J, Hobohm L, Jochimsen A, Desel C, Schweizer M, Voss M. Endogenous tagging reveals a mid-Golgi localization of the glycosyltransferase-cleaving intramembrane protease SPPL3. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119345. [PMID: 36007678 DOI: 10.1016/j.bbamcr.2022.119345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/16/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Numerous Golgi-resident enzymes implicated in glycosylation are regulated by the conserved intramembrane protease SPPL3. SPPL3-catalyzed endoproteolysis separates Golgi enzymes from their membrane anchors, enabling subsequent release from the Golgi and secretion. Experimentally altered SPPL3 expression changes glycosylation patterns, yet the regulation of SPPL3-mediated Golgi enzyme cleavage is not understood and conflicting results regarding the subcellular localization of SPPL3 have been reported. Here, we used precise genome editing to generate isogenic cell lines expressing N- or C-terminally tagged SPPL3 from its endogenous locus. Using these cells, we conducted co-localization analyses of tagged endogenous SPPL3 and Golgi markers under steady-state conditions and upon treatment with drugs disrupting Golgi organization. Our data demonstrate that endogenous SPPL3 is Golgi-resident and found predominantly in the mid-Golgi. We find that endogenous SPPL3 co-localizes with its substrates but similarly with non-substrate type II proteins, demonstrating that in addition to co-localization in the Golgi other substrate-intrinsic properties govern SPPL3-mediated intramembrane proteolysis. Given the prevalence of SPPL3-mediated cleavage among Golgi-resident proteins our results have important implications for the regulation of SPPL3 and its role in the organization of the Golgi glycosylation machinery.
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Affiliation(s)
- Jule Truberg
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, D-24118 Kiel, Germany
| | - Laura Hobohm
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, D-24118 Kiel, Germany
| | - Alexander Jochimsen
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, D-24118 Kiel, Germany
| | - Christine Desel
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, D-24118 Kiel, Germany
| | - Michaela Schweizer
- Morphology and Electron Microscopy, University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), 20251 Hamburg, Germany
| | - Matthias Voss
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, D-24118 Kiel, 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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Hobohm L, Koudelka T, Bahr FH, Truberg J, Kapell S, Schacht SS, Meisinger D, Mengel M, Jochimsen A, Hofmann A, Heintz L, Tholey A, Voss M. N-terminome analyses underscore the prevalence of SPPL3-mediated intramembrane proteolysis among Golgi-resident enzymes and its role in Golgi enzyme secretion. Cell Mol Life Sci 2022; 79:185. [PMID: 35279766 PMCID: PMC8918473 DOI: 10.1007/s00018-022-04163-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/07/2022] [Accepted: 01/22/2022] [Indexed: 12/17/2022]
Abstract
Golgi membrane proteins such as glycosyltransferases and other glycan-modifying enzymes are key to glycosylation of proteins and lipids. Secretion of soluble Golgi enzymes that are released from their membrane anchor by endoprotease activity is a wide-spread yet largely unexplored phenomenon. The intramembrane protease SPPL3 can specifically cleave select Golgi enzymes, enabling their secretion and concomitantly altering global cellular glycosylation, yet the entire range of Golgi enzymes cleaved by SPPL3 under physiological conditions remains to be defined. Here, we established isogenic SPPL3-deficient HEK293 and HeLa cell lines and applied N-terminomics to identify substrates cleaved by SPPL3 and released into cell culture supernatants. With high confidence, our study identifies more than 20 substrates of SPPL3, including entirely novel substrates. Notably, our N-terminome analyses provide a comprehensive list of SPPL3 cleavage sites demonstrating that SPPL3-mediated shedding of Golgi enzymes occurs through intramembrane proteolysis. Through the use of chimeric glycosyltransferase constructs we show that transmembrane domains can determine cleavage by SPPL3. Using our cleavage site data, we surveyed public proteome data and found that SPPL3 cleavage products are present in human blood. We also generated HEK293 knock-in cells expressing the active site mutant D271A from the endogenous SPPL3 locus. Immunoblot analyses revealed that secretion of select novel substrates such as the key mucin-type O-glycosylation enzyme GALNT2 is dependent on endogenous SPPL3 protease activity. In sum, our study expands the spectrum of known physiological substrates of SPPL3 corroborating its significant role in Golgi enzyme turnover and secretion as well as in the regulation of global glycosylation pathways.
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Affiliation(s)
- Laura Hobohm
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Tomas Koudelka
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Kiel University, 24105, Kiel, Germany
| | - Fenja H Bahr
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Jule Truberg
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Sebastian Kapell
- National Bioinformatics Infrastructure Sweden (NBIS), Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
| | - Sarah-Sophie Schacht
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
- Institute of Immunology, University Medical Center Schleswig-Holstein, 24105, Kiel, Germany
| | - Daniel Meisinger
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Marion Mengel
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Alexander Jochimsen
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Anna Hofmann
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
| | - Lukas Heintz
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany
- Institute for Cellular and Integrative Physiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Andreas Tholey
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Kiel University, 24105, Kiel, Germany
| | - Matthias Voss
- Institute of Biochemistry, Kiel University, Rudolf-Höber-Str. 1, 24118, Kiel, Germany.
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8
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Schwake C, Hyon M, Chishti AH. Signal peptide peptidase: A potential therapeutic target for parasitic and viral infections. Expert Opin Ther Targets 2022; 26:261-273. [PMID: 35235480 DOI: 10.1080/14728222.2022.2047932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Signal peptide peptidase (SPP) is a GxGD-type intramembrane-cleaving aspartyl protease responsible for clearing accumulating signal peptides in the endoplasmic reticulum. SPP is conserved among all kingdoms and is essential for maintaining cell homeostasis. Inhibition of SPP with selective inhibitors and the structurally similar HIV protease inhibitors results in signal peptide accumulation and subsequent cell death. Identification of SPP homologues in major human parasitic infections has opened a new therapeutic opportunity. Moreover, the essentiality of mammalian SPP-mediated viral protein processing during infection is emerging. AREAS COVERED This review introduces the discovery and biological function of human SPP enzymes and identify parasitic homologues as pharmacological targets of both SPP and HIV protease inhibitors. Later, the role of mammalian SPP during viral infection and how disruption of host SPP can be employed as a novel antiviral therapy are examined and discussed. EXPERT OPINION Parasitic and viral infections cause severe health and economic burden, exacerbated by the lack of new therapeutics in the pipeline. SPP has been shown to be essential for malaria parasite growth and encouraging evidence in other parasites demonstrates broad essentiality of these proteases as therapeutic targets. As drug resistant parasite and viruses emerge, SPP inhibition will provide a new generation of compounds to counter the growing threat of antimicrobial resistance.
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Affiliation(s)
- Christopher Schwake
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Michael Hyon
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Athar H Chishti
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
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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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The Unique, the Known, and the Unknown of Spumaretrovirus Assembly. Viruses 2021; 13:v13010105. [PMID: 33451128 PMCID: PMC7828637 DOI: 10.3390/v13010105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/08/2021] [Accepted: 01/10/2021] [Indexed: 12/22/2022] Open
Abstract
Within the family of Retroviridae, foamy viruses (FVs) are unique and unconventional with respect to many aspects in their molecular biology, including assembly and release of enveloped viral particles. Both components of the minimal assembly and release machinery, Gag and Env, display significant differences in their molecular structures and functions compared to the other retroviruses. This led to the placement of FVs into a separate subfamily, the Spumaretrovirinae. Here, we describe the molecular differences in FV Gag and Env, as well as Pol, which is translated as a separate protein and not in an orthoretroviral manner as a Gag-Pol fusion protein. This feature further complicates FV assembly since a specialized Pol encapsidation strategy via a tripartite Gag-genome–Pol complex is used. We try to relate the different features and specific interaction patterns of the FV Gag, Pol, and Env proteins in order to develop a comprehensive and dynamic picture of particle assembly and release, but also other features that are indirectly affected. Since FVs are at the root of the retrovirus tree, we aim at dissecting the unique/specialized features from those shared among the Spuma- and Orthoretrovirinae. Such analyses may shed light on the evolution and characteristics of virus envelopment since related viruses within the Ortervirales, for instance LTR retrotransposons, are characterized by different levels of envelopment, thus affecting the capacity for intercellular transmission.
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11
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Jongsma MLM, de Waard AA, Raaben M, Zhang T, Cabukusta B, Platzer R, Blomen VA, Xagara A, Verkerk T, Bliss S, Kong X, Gerke C, Janssen L, Stickel E, Holst S, Plomp R, Mulder A, Ferrone S, Claas FHJ, Heemskerk MHM, Griffioen M, Halenius A, Overkleeft H, Huppa JB, Wuhrer M, Brummelkamp TR, Neefjes J, Spaapen RM. The SPPL3-Defined Glycosphingolipid Repertoire Orchestrates HLA Class I-Mediated Immune Responses. Immunity 2021; 54:132-150.e9. [PMID: 33271119 PMCID: PMC8722104 DOI: 10.1016/j.immuni.2020.11.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 09/25/2020] [Accepted: 11/06/2020] [Indexed: 12/26/2022]
Abstract
HLA class I (HLA-I) glycoproteins drive immune responses by presenting antigens to cognate CD8+ T cells. This process is often hijacked by tumors and pathogens for immune evasion. Because options for restoring HLA-I antigen presentation are limited, we aimed to identify druggable HLA-I pathway targets. Using iterative genome-wide screens, we uncovered that the cell surface glycosphingolipid (GSL) repertoire determines effective HLA-I antigen presentation. We show that absence of the protease SPPL3 augmented B3GNT5 enzyme activity, resulting in upregulation of surface neolacto-series GSLs. These GSLs sterically impeded antibody and receptor interactions with HLA-I and diminished CD8+ T cell activation. Furthermore, a disturbed SPPL3-B3GNT5 pathway in glioma correlated with decreased patient survival. We show that the immunomodulatory effect could be reversed through GSL synthesis inhibition using clinically approved drugs. Overall, our study identifies a GSL signature that inhibits immune recognition and represents a potential therapeutic target in cancer, infection, and autoimmunity.
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Affiliation(s)
- Marlieke L M Jongsma
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands; Oncode Institute and Department of Cell and Chemical Biology, LUMC, Leiden, the Netherlands
| | - Antonius A de Waard
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Matthijs Raaben
- Oncode Institute, Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Tao Zhang
- Center for Proteomics and Metabolics, LUMC, Leiden, the Netherlands
| | - Birol Cabukusta
- Oncode Institute and Department of Cell and Chemical Biology, LUMC, Leiden, the Netherlands
| | - René Platzer
- Institut für Hygiene und Angewandte Immunologie, Vienna, Austria
| | - Vincent A Blomen
- Oncode Institute, Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Anastasia Xagara
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Tamara Verkerk
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Sophie Bliss
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Xiangrui Kong
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Carolin Gerke
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany; Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Lennert Janssen
- Oncode Institute and Department of Cell and Chemical Biology, LUMC, Leiden, the Netherlands
| | - Elmer Stickel
- Oncode Institute, Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Stephanie Holst
- Center for Proteomics and Metabolics, LUMC, Leiden, the Netherlands
| | - Rosina Plomp
- Center for Proteomics and Metabolics, LUMC, Leiden, the Netherlands
| | - Arend Mulder
- Department of Immunology, LUMC, Leiden, the Netherlands
| | - Soldano Ferrone
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Mirjam H M Heemskerk
- Department of Hematology, Leiden University Medical Center, Leiden, the Netherlands
| | - Marieke Griffioen
- Department of Hematology, Leiden University Medical Center, Leiden, the Netherlands
| | - Anne Halenius
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hermen Overkleeft
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
| | - Johannes B Huppa
- Institut für Hygiene und Angewandte Immunologie, Vienna, Austria
| | - Manfred Wuhrer
- Center for Proteomics and Metabolics, LUMC, Leiden, the Netherlands
| | - Thijn R Brummelkamp
- Oncode Institute, Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, the Netherlands; CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria; Cancer Genomics Center, Amsterdam, the Netherlands
| | - Jacques Neefjes
- Oncode Institute and Department of Cell and Chemical Biology, LUMC, Leiden, the Netherlands
| | - Robbert M Spaapen
- Department of Immunopathology, Sanquin Research, Amsterdam, the Netherlands; Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Cancer Center Amsterdam, Amsterdam, the Netherlands.
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12
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Spitz C, Schlosser C, Guschtschin-Schmidt N, Stelzer W, Menig S, Götz A, Haug-Kröper M, Scharnagl C, Langosch D, Muhle-Goll C, Fluhrer R. Non-canonical Shedding of TNFα by SPPL2a Is Determined by the Conformational Flexibility of Its Transmembrane Helix. iScience 2020; 23:101775. [PMID: 33294784 PMCID: PMC7689174 DOI: 10.1016/j.isci.2020.101775] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/21/2020] [Accepted: 11/03/2020] [Indexed: 12/22/2022] Open
Abstract
Ectodomain (EC) shedding defines the proteolytic removal of a membrane protein EC and acts as an important molecular switch in signaling and other cellular processes. Using tumor necrosis factor (TNF)α as a model substrate, we identify a non-canonical shedding activity of SPPL2a, an intramembrane cleaving aspartyl protease of the GxGD type. Proline insertions in the TNFα transmembrane (TM) helix strongly increased SPPL2a non-canonical shedding, while leucine mutations decreased this cleavage. Using biophysical and structural analysis, as well as molecular dynamic simulations, we identified a flexible region in the center of the TNFα wildtype TM domain, which plays an important role in the processing of TNFα by SPPL2a. This study combines molecular biology, biochemistry, and biophysics to provide insights into the dynamic architecture of a substrate's TM helix and its impact on non-canonical shedding. Thus, these data will provide the basis to identify further physiological substrates of non-canonical shedding in the future.
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Affiliation(s)
- Charlotte Spitz
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany
| | - Christine Schlosser
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany
| | - Nadja Guschtschin-Schmidt
- Karlsruhe Institute of Technology, Institute for Biological Interfaces 4, 76344 Eggenstein- Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute of Organic Chemistry, 76131 Karlsruhe, Germany
| | - Walter Stelzer
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Simon Menig
- Physics of Synthetic Biological Systems, Technische Universität München, Maximus-von-Imhof Forum 4, 85340 Freising, Germany
| | - Alexander Götz
- Present Address: Leibniz Supercomputing Centre, Boltzmannstr. 1, 85748 Garching, Germany
| | - Martina Haug-Kröper
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany
| | - Christina Scharnagl
- Physics of Synthetic Biological Systems, Technische Universität München, Maximus-von-Imhof Forum 4, 85340 Freising, Germany
| | - Dieter Langosch
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Claudia Muhle-Goll
- Karlsruhe Institute of Technology, Institute for Biological Interfaces 4, 76344 Eggenstein- Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute of Organic Chemistry, 76131 Karlsruhe, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany
- DZNE – German Center for Neurodegenerative Diseases, Feodor-Lynen-Str 17, 81377 Munich, Germany
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13
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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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14
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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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15
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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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16
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Papadopoulou AA, Müller SA, Mentrup T, Shmueli MD, Niemeyer J, Haug-Kröper M, von Blume J, Mayerhofer A, Feederle R, Schröder B, Lichtenthaler SF, Fluhrer R. Signal peptide peptidase-like 2c impairs vesicular transport and cleaves SNARE proteins. EMBO Rep 2019; 20:e46451. [PMID: 30733281 PMCID: PMC6399617 DOI: 10.15252/embr.201846451] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/07/2018] [Accepted: 12/21/2018] [Indexed: 12/25/2022] Open
Abstract
Members of the GxGD-type intramembrane aspartyl proteases have emerged as key players not only in fundamental cellular processes such as B-cell development or protein glycosylation, but also in development of pathologies, such as Alzheimer's disease or hepatitis virus infections. However, one member of this protease family, signal peptide peptidase-like 2c (SPPL2c), remains orphan and its capability of proteolysis as well as its physiological function is still enigmatic. Here, we demonstrate that SPPL2c is catalytically active and identify a variety of SPPL2c candidate substrates using proteomics. The majority of the SPPL2c candidate substrates cluster to the biological process of vesicular trafficking. Analysis of selected SNARE proteins reveals proteolytic processing by SPPL2c that impairs vesicular transport and causes retention of cargo proteins in the endoplasmic reticulum. As a consequence, the integrity of subcellular compartments, in particular the Golgi, is disturbed. Together with a strikingly high physiological SPPL2c expression in testis, our data suggest involvement of SPPL2c in acrosome formation during spermatogenesis.
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Affiliation(s)
- Alkmini A Papadopoulou
- Institute for Metabolic Biochemistry, Biomedical Center (BMC), Ludwig-Maximilians University Munich, Munich, Germany
| | - Stephan A Müller
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Torben Mentrup
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Merav D Shmueli
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
- Neuroproteomics, School of Medicine, Klinikum Rechts der Isar, and Institute for Advanced Study, Technical University Munich, Munich, Germany
| | - Johannes Niemeyer
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | - Martina Haug-Kröper
- Institute for Metabolic Biochemistry, Biomedical Center (BMC), Ludwig-Maximilians University Munich, Munich, Germany
| | | | - Artur Mayerhofer
- Cell Biology, Anatomy III, Biomedical Center (BMC), Ludwig-Maximilians University Munich, Munich, Germany
| | - Regina Feederle
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
- Institute for Physiological Chemistry, Technische Universität Dresden, Dresden, 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 Munich, Munich, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Regina Fluhrer
- Institute for Metabolic Biochemistry, Biomedical Center (BMC), Ludwig-Maximilians University Munich, Munich, Germany
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
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17
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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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18
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Avci D, Malchus NS, Heidasch R, Lorenz H, Richter K, Neßling M, Lemberg MK. The intramembrane protease SPP impacts morphology of the endoplasmic reticulum by triggering degradation of morphogenic proteins. J Biol Chem 2018; 294:2786-2800. [PMID: 30578301 DOI: 10.1074/jbc.ra118.005642] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/12/2018] [Indexed: 11/06/2022] Open
Abstract
The endoplasmic reticulum (ER), as a multifunctional organelle, plays crucial roles in lipid biosynthesis and calcium homeostasis as well as the synthesis and folding of secretory and membrane proteins. Therefore, it is of high importance to maintain ER homeostasis and to adapt ER function and morphology to cellular needs. Here, we show that signal peptide peptidase (SPP) modulates the ER shape through degradation of morphogenic proteins. Elevating SPP activity induces rapid rearrangement of the ER and formation of dynamic ER clusters. Inhibition of SPP activity rescues the phenotype without the need for new protein synthesis, and this rescue depends on a pre-existing pool of proteins in the Golgi. With the help of organelle proteomics, we identified certain membrane proteins to be diminished upon SPP expression and further show that the observed morphology changes depend on SPP-mediated cleavage of ER morphogenic proteins, including the SNARE protein syntaxin-18. Thus, we suggest that SPP-mediated protein abundance control by a regulatory branch of ER-associated degradation (ERAD-R) has a role in shaping the early secretory pathway.
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Affiliation(s)
- Dönem Avci
- From the Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and
| | - Nicole S Malchus
- From the Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and
| | - Ronny Heidasch
- From the Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and
| | - Holger Lorenz
- From the Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and
| | - Karsten Richter
- German Cancer Research Center (DKFZ), Central Unit Electron Microscopy, 69120 Heidelberg, Germany
| | - Michelle Neßling
- German Cancer Research Center (DKFZ), Central Unit Electron Microscopy, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- From the Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and
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19
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Lichtenthaler SF, Lemberg MK, Fluhrer R. Proteolytic ectodomain shedding of membrane proteins in mammals-hardware, concepts, and recent developments. EMBO J 2018; 37:e99456. [PMID: 29976761 PMCID: PMC6068445 DOI: 10.15252/embj.201899456] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/05/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
Proteolytic removal of membrane protein ectodomains (ectodomain shedding) is a post-translational modification that controls levels and function of hundreds of membrane proteins. The contributing proteases, referred to as sheddases, act as important molecular switches in processes ranging from signaling to cell adhesion. When deregulated, ectodomain shedding is linked to pathologies such as inflammation and Alzheimer's disease. While proteases of the "a disintegrin and metalloprotease" (ADAM) and "beta-site APP cleaving enzyme" (BACE) families are widely considered as sheddases, in recent years a much broader range of proteases, including intramembrane and soluble proteases, were shown to catalyze similar cleavage reactions. This review demonstrates that shedding is a fundamental process in cell biology and discusses the current understanding of sheddases and their substrates, molecular mechanisms and cellular localizations, as well as physiological functions of protein ectodomain shedding. Moreover, we provide an operational definition of shedding and highlight recent conceptual advances in the field. While new developments in proteomics facilitate substrate discovery, we expect that shedding is not a rare exception, but rather the rule for many membrane proteins, and that many more interesting shedding functions await discovery.
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Affiliation(s)
- Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, School of Medicine, and Institute for Advanced Study, Technical University Munich, Munich, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Regina Fluhrer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedizinisches Centrum (BMC), Ludwig-Maximilians University of Munich, Munich, Germany
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20
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Velcicky J, Bodendorf U, Rigollier P, Epple R, Beisner DR, Guerini D, Smith P, Liu B, Feifel R, Wipfli P, Aichholz R, Couttet P, Dix I, Widmer T, Wen B, Brandl T. Discovery of the First Potent, Selective, and Orally Bioavailable Signal Peptide Peptidase-Like 2a (SPPL2a) Inhibitor Displaying Pronounced Immunomodulatory Effects In Vivo. J Med Chem 2018; 61:865-880. [DOI: 10.1021/acs.jmedchem.7b01371] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | | | | | - Robert Epple
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Daniel R. Beisner
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | | | | | - Bo Liu
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | | | | | | | | | | | - Toni Widmer
- Chemical
and Pharmaceutical Profiling, Global Drug Development, Novartis Pharma AG, CH-4002 Basel, Switzerland
| | - Ben Wen
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
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Jules F, Sauvageau E, Dumaresq-Doiron K, Mazzaferri J, Haug-Kröper M, Fluhrer R, Costantino S, Lefrancois S. CLN5 is cleaved by members of the SPP/SPPL family to produce a mature soluble protein. Exp Cell Res 2017; 357:40-50. [PMID: 28442266 DOI: 10.1016/j.yexcr.2017.04.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 04/19/2017] [Accepted: 04/21/2017] [Indexed: 11/30/2022]
Abstract
The Neuronal ceroid lipofuscinoses (NCLs) are a group of recessive disorders of childhood with overlapping symptoms including vision loss, ataxia, cognitive regression and premature death. 14 different genes have been linked to NCLs (CLN1-CLN14), but the functions of the proteins encoded by the majority of these genes have not been fully elucidated. Mutations in the CLN5 gene are responsible for the Finnish variant late-infantile form of NCL (Finnish vLINCL). CLN5 is translated as a 407 amino acid transmembrane domain containing protein that is heavily glycosylated, and subsequently cleaved into a mature soluble protein. Functionally, CLN5 is implicated in the recruitment of the retromer complex to endosomes, which is required to sort the lysosomal sorting receptors from endosomes to the trans-Golgi network. The mechanism that processes CLN5 into a mature soluble protein is currently not known. Herein, we demonstrate that CLN5 is initially translated as a type II transmembrane protein and subsequently cleaved by SPPL3, a member of the SPP/SPPL intramembrane protease family, into a mature soluble protein consisting of residues 93-407. The remaining N-terminal fragment is then cleaved by SPPL3 and SPPL2b and degraded in the proteasome. This work further characterizes the biology of CLN5 in the hopes of identifying a novel therapeutic strategy for affected children.
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Affiliation(s)
- Felix Jules
- Centre INRS-Institut Armand-Frappier, INRS, Laval, Canada H7V 1B7
| | | | | | - Javier Mazzaferri
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Canada H1T 2M4
| | - Martina Haug-Kröper
- Biomedical Center (BMC), Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Regina Fluhrer
- Biomedical Center (BMC), Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany; DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Santiago Costantino
- Département d'Ophtalmologie et Institut de Génie Biomédical, Université de Montréal, Montréal, Canada H3T 1J4; Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Canada H1T 2M4
| | - Stephane Lefrancois
- Centre INRS-Institut Armand-Frappier, INRS, Laval, Canada H7V 1B7; Department of Anatomy and Cell Biology, McGill University, Montreal, Canada H3A 2B2.
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22
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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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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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Mouse Mammary Tumor Virus Signal Peptide Uses a Novel p97-Dependent and Derlin-Independent Retrotranslocation Mechanism To Escape Proteasomal Degradation. mBio 2017; 8:mBio.00328-17. [PMID: 28351922 PMCID: PMC5371415 DOI: 10.1128/mbio.00328-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Multiple pathogens, including viruses and bacteria, manipulate endoplasmic reticulum-associated degradation (ERAD) to avoid the host immune response and promote their replication. The betaretrovirus mouse mammary tumor virus (MMTV) encodes Rem, which is a precursor protein that is cleaved into a 98-amino-acid signal peptide (SP) and a C-terminal protein (Rem-CT). SP uses retrotranslocation for ER membrane extraction and yet avoids ERAD by an unknown mechanism to enter the nucleus and function as a Rev-like protein. To determine how SP escapes ERAD, we used a ubiquitin-activated interaction trap (UBAIT) screen to trap and identify transient protein interactions with SP, including the ERAD-associated p97 ATPase, but not E3 ligases or Derlin proteins linked to retrotranslocation, polyubiquitylation, and proteasomal degradation of extracted proteins. A dominant negative p97 ATPase inhibited both Rem and SP function. Immunoprecipitation experiments indicated that Rem, but not SP, is polyubiquitylated. Using both yeast and mammalian expression systems, linkage of a ubiquitin-like domain (UbL) to SP or Rem induced degradation by the proteasome, whereas SP was stable in the absence of the UbL. ERAD-associated Derlin proteins were not required for SP activity. Together, these results suggested that Rem uses a novel p97-dependent, Derlin-independent retrotranslocation mechanism distinct from other pathogens to avoid SP ubiquitylation and proteasomal degradation. Bacterial and viral infections produce pathogen-specific proteins that interfere with host functions, including the immune response. Mouse mammary tumor virus (MMTV) is a model system for studies of human complex retroviruses, such as HIV-1, as well as cancer induction. We have shown that MMTV encodes a regulatory protein, Rem, which is cleaved into an N-terminal signal peptide (SP) and a C-terminal protein (Rem-CT) within the endoplasmic reticulum (ER) membrane. SP function requires ER membrane extraction by retrotranslocation, which is part of a protein quality control system known as ER-associated degradation (ERAD) that is essential to cellular health. Through poorly understood mechanisms, certain pathogen-derived proteins are retrotranslocated but not degraded. We demonstrate here that MMTV SP retrotranslocation from the ER membrane avoids degradation through a unique process involving interaction with cellular p97 ATPase and failure to acquire cellular proteasome-targeting sequences.
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25
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Chang H, Smallwood PM, Williams J, Nathans J. Intramembrane Proteolysis of Astrotactins. J Biol Chem 2017; 292:3506-3516. [PMID: 28100779 DOI: 10.1074/jbc.m116.768077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/14/2017] [Indexed: 11/06/2022] Open
Abstract
Astrotactins are vertebrate-specific membrane proteins implicated in neuron-glia interactions during central nervous system development and in hair follicle polarity during skin development. By studying epitope-tagged derivatives of mouse astrotactin-2 (Astn2) produced in transfected cells, we determined that the amino and carboxyl termini reside in the extracellular space and are initially linked by two transmembrane segments and a single cytoplasmic domain. We further show that Astn2 undergoes proteolytic cleavage in the second transmembrane domain (TM2) and that a disulfide bond holds the resulting two fragments together. Recombinant Astn1 also undergoes TM2 cleavage, as does Astn2 isolated from mouse cerebellum. Astn2 intramembrane proteolysis is insensitive to replacement of TM2 by the transmembrane domain of CD74 or by 21 alanines. However, replacement of TM2 by the transmembrane domain of CD4, the asialoglycoprotein receptor, or the transferrin receptor eliminates intramembrane proteolysis, as does leucine substitution of residues that overlap or are immediately upstream of the cleavage site. Replacement of the transmembrane domain of CD74 or the asialoglycoprotein receptor with Astn2 TM2 leads to the appearance of a carboxyl-terminal fragment consistent with intramembrane proteolysis. These experiments define a highly unusual transmembrane topology for the astrotactins, reveal intramembrane proteolysis as a feature of astrotactin maturation, and constrain the substrate sequences that are permissive for cleavage of one type 2 transmembrane segment.
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Affiliation(s)
- Hao Chang
- Departments of Molecular Biology and Genetics
| | | | | | - Jeremy Nathans
- Departments of Molecular Biology and Genetics; Neuroscience; Ophthalmology, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
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26
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Müller SA, Scilabra SD, Lichtenthaler SF. Proteomic Substrate Identification for Membrane Proteases in the Brain. Front Mol Neurosci 2016; 9:96. [PMID: 27790089 PMCID: PMC5062031 DOI: 10.3389/fnmol.2016.00096] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 09/21/2016] [Indexed: 12/26/2022] Open
Abstract
Cell-cell communication in the brain is controlled by multiple mechanisms, including proteolysis. Membrane-bound proteases generate signaling molecules from membrane-bound precursor proteins and control the length and function of cell surface membrane proteins. These proteases belong to different families, including members of the “a disintegrin and metalloprotease” (ADAM), the beta-site amyloid precursor protein cleaving enzymes (BACE), membrane-type matrix metalloproteases (MT-MMP) and rhomboids. Some of these proteases, in particular ADAM10 and BACE1 have been shown to be essential not only for the correct development of the mammalian brain, but also for myelination and maintaining neuronal connections in the adult nervous system. Additionally, these proteases are considered as drug targets for brain diseases, including Alzheimer’s disease (AD), schizophrenia and cancer. Despite their biomedical relevance, the molecular functions of these proteases in the brain have not been explored in much detail, as little was known about their substrates. This has changed with the recent development of novel proteomic methods which allow to identify substrates of membrane-bound proteases from cultured cells, primary neurons and other primary brain cells and even in vivo from minute amounts of mouse cerebrospinal fluid (CSF). This review summarizes the recent advances and highlights the strengths of the individual proteomic methods. Finally, using the example of the Alzheimer-related proteases BACE1, ADAM10 and γ-secretase, as well as ADAM17 and signal peptide peptidase like 3 (SPPL3), we illustrate how substrate identification with novel methods is instrumental in elucidating broad physiological functions of these proteases in the brain and other organs.
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Affiliation(s)
- Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE)Munich, Germany; Neuroproteomics, Klinikum rechts der Isar, Technische Universität MünchenMunich, Germany
| | - Simone D Scilabra
- German Center for Neurodegenerative Diseases (DZNE)Munich, Germany; Neuroproteomics, Klinikum rechts der Isar, Technische Universität MünchenMunich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE)Munich, Germany; Neuroproteomics, Klinikum rechts der Isar, Technische Universität MünchenMunich, Germany; Institute for Advanced Study, Technische Universität MunichGarching, Germany; Munich Cluster for Systems Neurology (SyNergy)Munich, Germany
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27
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Hamblet CE, Makowski SL, Tritapoe JM, Pomerantz JL. NK Cell Maturation and Cytotoxicity Are Controlled by the Intramembrane Aspartyl Protease SPPL3. THE JOURNAL OF IMMUNOLOGY 2016; 196:2614-26. [PMID: 26851218 DOI: 10.4049/jimmunol.1501970] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/16/2016] [Indexed: 11/19/2022]
Abstract
NK cell maturation is critical for normal effector function and the innate immune response to tumors and pathogens. However, the molecular pathways that control NK cell maturation remain largely undefined. In this article, we investigate the role of SPPL3, an intramembrane aspartyl protease, in murine NK cell biology. We find that deletion of SPPL3 in the hematopoietic system reduces numbers of peripheral NK cells, clearance of MHC class I-deficient tumors in vivo, and cytotoxicity against tumor cells in vitro. This phenotype is concomitant with reduced numbers of CD27(+)CD11b(+) and CD27(-)CD11b(+) NK cells, indicating a requirement for SPPL3 in efficient NK cell maturation. NK cell-specific deletion of SPPL3 results in the same deficiencies, revealing a cell-autonomous role for SPPL3 in these processes. CRISPR/Cas9 genomic editing in murine zygotes was used to generate knockin mice with a catalytically compromised SPPL3 D271A allele. Mice engineered to express only SPPL3 D271A in NK cells phenocopy mice deleted for SPPL3, indicating a requirement for SPPL3 protease activity in NK cell biology. Our results identify SPPL3 as a cell-autonomous molecular determinant of NK cell maturation and expand the role of intramembrane aspartyl proteases in innate immunity.
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Affiliation(s)
- Corinne E Hamblet
- Department of Biological Chemistry, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Stefanie L Makowski
- Department of Biological Chemistry, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Julia M Tritapoe
- Department of Biological Chemistry, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Joel L Pomerantz
- Department of Biological Chemistry, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
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28
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Fleck D, Voss M, Brankatschk B, Giudici C, Hampel H, Schwenk B, Edbauer D, Fukumori A, Steiner H, Kremmer E, Haug-Kröper M, Rossner MJ, Fluhrer R, Willem M, Haass C. Proteolytic Processing of Neuregulin 1 Type III by Three Intramembrane-cleaving Proteases. J Biol Chem 2015; 291:318-33. [PMID: 26574544 DOI: 10.1074/jbc.m115.697995] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Numerous membrane-bound proteins undergo regulated intramembrane proteolysis. Regulated intramembrane proteolysis is initiated by shedding, and the remaining stubs are further processed by intramembrane-cleaving proteases (I-CLiPs). Neuregulin 1 type III (NRG1 type III) is a major physiological substrate of β-secretase (β-site amyloid precursor protein-cleaving enzyme 1 (BACE1)). BACE1-mediated cleavage is required to allow signaling of NRG1 type III. Because of the hairpin nature of NRG1 type III, two membrane-bound stubs with a type 1 and a type 2 orientation are generated by proteolytic processing. We demonstrate that these stubs are substrates for three I-CLiPs. The type 1-oriented stub is further cleaved by γ-secretase at an ϵ-like site five amino acids N-terminal to the C-terminal membrane anchor and at a γ-like site in the middle of the transmembrane domain. The ϵ-cleavage site is only one amino acid N-terminal to a Val/Leu substitution associated with schizophrenia. The mutation reduces generation of the NRG1 type III β-peptide as well as reverses signaling. Moreover, it affects the cleavage precision of γ-secretase at the γ-site similar to certain Alzheimer disease-associated mutations within the amyloid precursor protein. The type 2-oriented membrane-retained stub of NRG1 type III is further processed by signal peptide peptidase-like proteases SPPL2a and SPPL2b. Expression of catalytically inactive aspartate mutations as well as treatment with 2,2'-(2-oxo-1,3-propanediyl)bis[(phenylmethoxy)carbonyl]-l-leucyl-l-leucinamide ketone inhibits formation of N-terminal intracellular domains and the corresponding secreted C-peptide. Thus, NRG1 type III is the first protein substrate that is not only cleaved by multiple sheddases but is also processed by three different I-CLiPs.
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Affiliation(s)
- Daniel Fleck
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Matthias Voss
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Ben Brankatschk
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Camilla Giudici
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Heike Hampel
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Benjamin Schwenk
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Dieter Edbauer
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
| | - Akio Fukumori
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Harald Steiner
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Elisabeth Kremmer
- the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and the Institute of Molecular Immunology, Helmholtz Center Munich, 81377 Munich, Germany
| | - Martina Haug-Kröper
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Moritz J Rossner
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Regina Fluhrer
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Michael Willem
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich,
| | - Christian Haass
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
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29
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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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30
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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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31
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Kuhn PH, Voss M, Haug-Kröper M, Schröder B, Schepers U, Bräse S, Haass C, Lichtenthaler SF, Fluhrer R. Secretome analysis identifies novel signal Peptide peptidase-like 3 (Sppl3) substrates and reveals a role of Sppl3 in multiple Golgi glycosylation pathways. Mol Cell Proteomics 2015; 14:1584-98. [PMID: 25827571 DOI: 10.1074/mcp.m115.048298] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022] Open
Abstract
Signal peptide peptidase-like 3 (Sppl3) is a Golgi-resident intramembrane-cleaving protease that is highly conserved among multicellular eukaryotes pointing to pivotal physiological functions in the Golgi network which are only beginning to emerge. Recently, Sppl3 was shown to control protein N-glycosylation, when the key branching enzyme N-acetylglucosaminyltransferase V (GnT-V) and other medial/trans Golgi glycosyltransferases were identified as first physiological Sppl3 substrates. Sppl3-mediated endoproteolysis releases the catalytic ectodomains of these enzymes from their type II membrane anchors. Protein glycosylation is a multistep process involving numerous type II membrane-bound enzymes, but it remains unclear whether only few of them are Sppl3 substrates or whether Sppl3 cleaves many of them and thereby controls protein glycosylation at multiple levels. Therefore, to systematically identify Sppl3 substrates we used Sppl3-deficient and Sppl3-overexpression cell culture models and analyzed them for changes in secreted membrane protein ectodomains using the proteomics "secretome protein enrichment with click sugars (SPECS)" method. SPECS analysis identified numerous additional new Sppl3 candidate glycoprotein substrates, several of which were biochemically validated as Sppl3 substrates. All novel Sppl3 substrates adopt a type II topology. The majority localizes to the Golgi network and is implicated in Golgi functions. Importantly, most of the novel Sppl3 substrates catalyze the modification of N-linked glycans. Others contribute to O-glycan and in particular glycosaminoglycan biosynthesis, suggesting that Sppl3 function is not restricted to N-glycosylation, but also functions in other forms of protein glycosylation. Hence, Sppl3 emerges as a crucial player of Golgi function and the newly identified Sppl3 substrates will be instrumental to investigate the molecular mechanisms underlying the physiological function of Sppl3 in the Golgi network and in vivo. Data are available via ProteomeXchange with identifier PXD001672.
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Affiliation(s)
- Peer-Hendrik Kuhn
- From the DZNE - German Center for Neurodegenerative Diseases, Munich, Germany; Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Matthias Voss
- Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Martina Haug-Kröper
- Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24118 Kiel, Germany
| | - Ute Schepers
- Institute of Toxicology and Genetics, KIT, Campus North, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Stefan Bräse
- Institute of Toxicology and Genetics, KIT, Campus North, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- From the DZNE - German Center for Neurodegenerative Diseases, Munich, Germany; Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Stefan F Lichtenthaler
- From the DZNE - German Center for Neurodegenerative Diseases, Munich, Germany; Institute for Advanced Study, Technische Universität München, Garching, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Regina Fluhrer
- From the DZNE - German Center for Neurodegenerative Diseases, Munich, Germany; Institute for Metabolic Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany;
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Abstract
The signal peptide peptidase (SPP)-related intramembrane aspartyl proteases are a homologous group of polytopic membrane proteins, some of which function in innate or adaptive immunity by cleaving proteins involved in antigen presentation or intracellular signaling. Signal peptide peptidase-like 3 (SPPL3) is a poorly characterized endoplasmic reticulum (ER)-localized member of this family, with no validated cellular substrates. We report here the isolation of SPPL3 in a screen for activators of NFAT, a transcription factor that controls lymphocyte development and function. We find that SPPL3 is required downstream of T cell receptor engagement for maximal Ca(2+) influx and NFAT activation. Surprisingly, the proteolytic activity of SPPL3 is not required for its role in this pathway. SPPL3 enhances the signal-induced association of stromal interaction molecule 1 (STIM1) and Orai1 and is even required for the full activity of constitutively active STIM1 variants that bind Orai1 independently of ER Ca(2+) release. SPPL3 associates with STIM1 through at least two independent domains, the transmembrane region and the CRAC activation domain (CAD), and can promote the association of the STIM1 CAD with Orai1. Our results assign a function in lymphocyte signaling to SPPL3 and highlight the emerging importance of nonproteolytic functions for members of the intramembrane aspartyl protease family.
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Voss M, Künzel U, Higel F, Kuhn PH, Colombo A, Fukumori A, Haug-Kröper M, Klier B, Grammer G, Seidl A, Schröder B, Obst R, Steiner H, Lichtenthaler SF, Haass C, Fluhrer R. Shedding of glycan-modifying enzymes by signal peptide peptidase-like 3 (SPPL3) regulates cellular N-glycosylation. EMBO J 2014; 33:2890-905. [PMID: 25354954 DOI: 10.15252/embj.201488375] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Protein N-glycosylation is involved in a variety of physiological and pathophysiological processes such as autoimmunity, tumour progression and metastasis. Signal peptide peptidase-like 3 (SPPL3) is an intramembrane-cleaving aspartyl protease of the GxGD type. Its physiological function, however, has remained enigmatic, since presently no physiological substrates have been identified. We demonstrate that SPPL3 alters the pattern of cellular N-glycosylation by triggering the proteolytic release of active site-containing ectodomains of glycosidases and glycosyltransferases such as N-acetylglucosaminyltransferase V, β-1,3 N-acetylglucosaminyltransferase 1 and β-1,4 galactosyltransferase 1. Cleavage of these enzymes leads to a reduction in their cellular activity. In line with that, reduced expression of SPPL3 results in a hyperglycosylation phenotype, whereas elevated SPPL3 expression causes hypoglycosylation. Thus, SPPL3 plays a central role in an evolutionary highly conserved post-translational process in eukaryotes.
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Affiliation(s)
- Matthias Voss
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Ulrike Künzel
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Fabian Higel
- Sandoz Biopharmaceuticals/HEXAL AG, Oberhaching, Germany
| | - Peer-Hendrik Kuhn
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Alessio Colombo
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Akio Fukumori
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Martina Haug-Kröper
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Bärbel Klier
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Gudula Grammer
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Andreas Seidl
- Sandoz Biopharmaceuticals/HEXAL AG, Oberhaching, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Reinhard Obst
- Institute for Immunology, Ludwig-Maximilians University Munich, Munich, Germany
| | - Harald Steiner
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Stefan F Lichtenthaler
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Christian Haass
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Regina Fluhrer
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
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34
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Chen CY, Malchus NS, Hehn B, Stelzer W, Avci D, Langosch D, Lemberg MK. Signal peptide peptidase functions in ERAD to cleave the unfolded protein response regulator XBP1u. EMBO J 2014; 33:2492-506. [PMID: 25239945 DOI: 10.15252/embj.201488208] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Signal peptide peptidase (SPP) catalyzes intramembrane proteolysis of signal peptides at the endoplasmic reticulum (ER), but has also been suggested to play a role in ER-associated degradation (ERAD). Here, we show that SPP forms a complex with the ERAD factor Derlin1 and the E3 ubiquitin ligase TRC8 to cleave the unfolded protein response (UPR) regulator XBP1u. Cleavage occurs within a so far unrecognized type II transmembrane domain, which renders XBP1u as an SPP substrate through specific sequence features. Additionally, Derlin1 acts in the complex as a substrate receptor by recognizing the luminal tail of XBP1u. Remarkably, this interaction of Derlin1 with XBP1u obviates the need for ectodomain shedding prior to SPP cleavage, commonly required for intramembrane cuts. Furthermore, we show that XBP1u inhibits the UPR transcription factor XBP1s by targeting it toward proteasomal degradation. Thus, we identify an ERAD complex that controls the abundance of XBP1u and thereby tunes signaling through the UPR.
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Affiliation(s)
- Chia-yi Chen
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Nicole S Malchus
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Beate Hehn
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Walter Stelzer
- Lehrstuhl für Chemie der Biopolymere, Department für Biowissenschaftliche Grundlagen, Technische Universität München, Freising, Germany
| | - Dönem Avci
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) DKFZ-ZMBH Allianz, Heidelberg, Germany
| | - Dieter Langosch
- Lehrstuhl für Chemie der Biopolymere, Department für Biowissenschaftliche Grundlagen, Technische Universität München, Freising, Germany
| | - Marius K Lemberg
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) DKFZ-ZMBH Allianz, Heidelberg, Germany
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35
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Voss M, Schröder B, Fluhrer R. Mechanism, specificity, and physiology of signal peptide peptidase (SPP) and SPP-like proteases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2828-39. [PMID: 24099004 DOI: 10.1016/j.bbamem.2013.03.033] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/25/2013] [Accepted: 03/29/2013] [Indexed: 01/09/2023]
Abstract
Signal peptide peptidase (SPP) and the homologous SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 belong to the family of GxGD intramembrane proteases. SPP/SPPLs selectively cleave transmembrane domains in type II orientation and do not require additional co-factors for proteolytic activity. Orthologues of SPP and SPPLs have been identified in other vertebrates, plants, and eukaryotes. In line with their diverse subcellular localisations ranging from the ER (SPP, SPPL2c), the Golgi (SPPL3), the plasma membrane (SPPL2b) to lysosomes/late endosomes (SPPL2a), the different members of the SPP/SPPL family seem to exhibit distinct functions. Here, we review the substrates of these proteases identified to date as well as the current state of knowledge about the physiological implications of these proteolytic events as deduced from in vivo studies. Furthermore, the present knowledge on the structure of intramembrane proteases of the SPP/SPPL family, their cleavage mechanism and their substrate requirements are summarised. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Matthias Voss
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Schillerstr. 44, 80336 Munich, Germany
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36
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Golde TE, Koo EH, Felsenstein KM, Osborne BA, Miele L. γ-Secretase inhibitors and modulators. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1828:2898-907. [PMID: 23791707 PMCID: PMC3857966 DOI: 10.1016/j.bbamem.2013.06.005] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/04/2013] [Indexed: 12/11/2022]
Abstract
γ-Secretase is a fascinating, multi-subunit, intramembrane cleaving protease that is now being considered as a therapeutic target for a number of diseases. Potent, orally bioavailable γ-secretase inhibitors (GSIs) have been developed and tested in humans with Alzheimer's disease (AD) and cancer. Preclinical studies also suggest the therapeutic potential for GSIs in other disease conditions. However, due to inherent mechanism based-toxicity of non-selective inhibition of γ-secretase, clinical development of GSIs will require empirical testing with careful evaluation of benefit versus risk. In addition to GSIs, compounds referred to as γ-secretase modulators (GSMs) remain in development as AD therapeutics. GSMs do not inhibit γ-secretase, but modulate γ-secretase processivity and thereby shift the profile of the secreted amyloid β peptides (Aβ) peptides produced. Although GSMs are thought to have an inherently safe mechanism of action, their effects on substrates other than the amyloid β protein precursor (APP) have not been extensively investigated. Herein, we will review the current state of development of GSIs and GSMs and explore pertinent biological and pharmacological questions pertaining to the use of these agents for select indications. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
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37
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Ye J. Roles of regulated intramembrane proteolysis in virus infection and antiviral immunity. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1828:2926-32. [PMID: 24099010 PMCID: PMC3837687 DOI: 10.1016/j.bbamem.2013.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 01/24/2023]
Abstract
Regulated intramembrane proteolysis (RIP) is a signaling mechanism through which transmembrane precursor proteins are cleaved to liberate their cytoplasmic and/or luminal/extracellular fragments from membranes so that these fragments are able to function at a new location. Recent studies have indicated that this proteolytic reaction plays an important role in host-virus interaction. On one hand, RIP transfers the signal from the endoplasmic reticulum (ER) to nucleus to activate antiviral genes in response to alteration of the ER caused by viral infection. On the other hand, RIP can be hijacked by virus to process transmembrane viral protein precursors and to destroy transmembrane antiviral proteins. Understanding this Yin and Yang side of RIP may lead to new strategies to combat viral infection. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Jin Ye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9046, USA.
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38
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Hütter S, Zurnic I, Lindemann D. Foamy virus budding and release. Viruses 2013; 5:1075-98. [PMID: 23575110 PMCID: PMC3705266 DOI: 10.3390/v5041075] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/25/2013] [Accepted: 03/29/2013] [Indexed: 12/21/2022] Open
Abstract
Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems.
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Affiliation(s)
- Sylvia Hütter
- Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Fetscherstr. 74, Dresden 01307, Germany; E-Mails: (S.H); (I.Z.)
- DFG-Center for Regenerative Therapies Dresden (CRTD)—Cluster of Excellence, Technische Universität Dresden, Fetscherstr. 105, Dresden 01307, Germany
| | - Irena Zurnic
- Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Fetscherstr. 74, Dresden 01307, Germany; E-Mails: (S.H); (I.Z.)
- DFG-Center for Regenerative Therapies Dresden (CRTD)—Cluster of Excellence, Technische Universität Dresden, Fetscherstr. 105, Dresden 01307, Germany
| | - Dirk Lindemann
- Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Fetscherstr. 74, Dresden 01307, Germany; E-Mails: (S.H); (I.Z.)
- DFG-Center for Regenerative Therapies Dresden (CRTD)—Cluster of Excellence, Technische Universität Dresden, Fetscherstr. 105, Dresden 01307, Germany
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-351458-6210; Fax: +49-351-458-6310
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