1
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Roboti P, Lawless C, High S. Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex. J Cell Sci 2022; 135:275354. [PMID: 35543156 PMCID: PMC9264363 DOI: 10.1242/jcs.259596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/01/2022] [Indexed: 11/20/2022] Open
Abstract
The heterotrimeric BAG6 complex coordinates the direct handover of newly synthesised tail-anchored (TA) membrane proteins from an SGTA-bound preloading complex to the endoplasmic reticulum (ER) delivery component TRC40. In contrast, defective precursors, including aberrant TA proteins, form a stable complex with this cytosolic protein quality control factor, enabling such clients to be either productively re-routed or selectively degraded. We identify the mitochondrial antiviral-signalling protein (MAVS) as an endogenous TA client of both SGTA and the BAG6 complex. Our data suggest that the BAG6 complex binds to a cytosolic pool of MAVS before its misinsertion into the ER membrane, from where it can subsequently be removed via ATP13A1-mediated dislocation. This BAG6-associated fraction of MAVS is dynamic and responds to the activation of an innate immune response, suggesting that BAG6 may modulate the pool of MAVS that is available for coordinating the cellular response to viral infection. Summary: Mitochondrial antiviral-signalling protein (MAVS) is a favoured client of the cytosolic BAG6 complex. We discuss how this dynamic interaction may modulate MAVS biogenesis at signalling membranes.
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Affiliation(s)
- Peristera Roboti
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Craig Lawless
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Stephen High
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
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2
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Lavenus SB, Vosatka KW, Caruso AP, Ullo MF, Khan A, Logue JS. Emerin regulation of nuclear stiffness is required for fast amoeboid migration in confined environments. J Cell Sci 2022; 135:274946. [PMID: 35362531 DOI: 10.1242/jcs.259493] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/17/2022] [Indexed: 11/20/2022] Open
Abstract
When metastasizing, tumor cells must traverse environments with diverse physicochemical properties. Recently, the cell nucleus has emerged as a major regulator of the transition from mesenchymal to fast amoeboid (leader bleb-based) migration. Here, in melanoma cells, we demonstrate that increasing nuclear stiffness through elevating Lamin A, inhibits fast amoeboid migration. Importantly, nuclei may respond to force through stiffening. A key factor in this process is the inner nuclear membrane (INM) protein, emerin. Accordingly, we determined the role of emerin in regulating fast amoeboid migration. Strikingly, we found that both the up- and down-regulation of emerin results in an inhibition of fast amoeboid migration. However, when key Src phosphorylation sites were removed, up-regulation of emerin no longer inhibited fast amoeboid migration. Interestingly, in confined cells, Src activity was low, as measured by a Src biosensor. Thus, the fast amoeboid migration of melanoma cells depends on the precise calibration of emerin activity.
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Affiliation(s)
- Sandrine B Lavenus
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | - Karl W Vosatka
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | - Alexa P Caruso
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | - Maria F Ullo
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | - Ayesha Khan
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
| | - Jeremy S Logue
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA
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3
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James C, Lenz C, Urlaub H, Kehlenbach RH. Sequestosome 1 Is Part of the Interaction Network of VAPB. Int J Mol Sci 2021; 22:ijms222413271. [PMID: 34948065 PMCID: PMC8707790 DOI: 10.3390/ijms222413271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/01/2021] [Accepted: 12/07/2021] [Indexed: 12/14/2022] Open
Abstract
VAPB (Vesicle-Associated-membrane Protein-associated protein B) is a tail-anchored membrane protein of the endoplasmic reticulum that can also be detected at the inner nuclear membrane. As a component of many contact sites between the endoplasmic reticulum and other organelles, VAPB is engaged in multiple protein interactions with a plethora of binding partners. A mutant version of VAPB, P56S-VAPB, which results from a single point mutation, is involved in a familial form of amyotrophic lateral sclerosis (ALS8). We performed RAPIDS (rapamycin- and APEX-dependent identification of proteins by SILAC) to identify proteins that interact with or are in close proximity to P56S-VAPB. The mutation abrogates the interaction of VAPB with many known binding partners. Here, we identify Sequestosome 1 (SQSTM1), a well-known autophagic adapter protein, as a major interaction/proximity partner of P56S-VAPB. Remarkably, not only the mutant protein, but also wild-type VAPB interacts with SQSTM1, as shown by proximity ligation assays and co-immunoprecipiation experiments.
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Affiliation(s)
- Christina James
- Department of Molecular Biology, Faculty of Medicine, GZMB (Göttinger Zentrum für Molekulare Biowissenschaften), Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Correspondence: (C.J.); (R.H.K.)
| | - Christof Lenz
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany; (C.L.); (H.U.)
| | - Henning Urlaub
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany; (C.L.); (H.U.)
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ralph H. Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB (Göttinger Zentrum für Molekulare Biowissenschaften), Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Correspondence: (C.J.); (R.H.K.)
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4
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Endoplasmic reticulum membrane receptors of the GET pathway are conserved throughout eukaryotes. Proc Natl Acad Sci U S A 2020; 118:2017636118. [PMID: 33443185 PMCID: PMC7817167 DOI: 10.1073/pnas.2017636118] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The GET pathway is required for the insertion of tail-anchored (TA) membrane proteins in the endoplasmic reticulum (ER) of yeast and mammals. Some orthologous genes had also been identified in higher plants with the exception of one of the two ER membrane receptors required for membrane insertion. Get2/CAML is required for the pathway’s cytosolic chaperone to dock and release its TA protein cargo. Here we report the identification of the elusive plant GET pathway receptor through an interaction screen in Arabidopsis. The candidate allows detection of further Get2/CAML orthologs in higher plants, revealing conservation and function of structural features across kingdoms. Additionally, our results demonstrate that these features, rather than sequence conservation, determine functionality of the candidate within the pathway. Type II tail-anchored (TA) membrane proteins are involved in diverse cellular processes, including protein translocation, vesicle trafficking, and apoptosis. They are characterized by a single C-terminal transmembrane domain that mediates posttranslational targeting and insertion into the endoplasmic reticulum (ER) via the Guided-Entry of TA proteins (GET) pathway. The GET system was originally described in mammals and yeast but was recently shown to be partially conserved in other eukaryotes, such as higher plants. A newly synthesized TA protein is shielded from the cytosol by a pretargeting complex and an ATPase that delivers the protein to the ER, where membrane receptors (Get1/WRB and Get2/CAML) facilitate insertion. In the model plant Arabidopsis thaliana, most components of the pathway were identified through in silico sequence comparison, however, a functional homolog of the coreceptor Get2/CAML remained elusive. We performed immunoprecipitation-mass spectrometry analysis to detect in vivo interactors of AtGET1 and identified a membrane protein of unknown function with low sequence homology but high structural homology to both yeast Get2 and mammalian CAML. The protein localizes to the ER membrane, coexpresses with AtGET1, and binds to Arabidopsis GET pathway components. While loss-of-function lines phenocopy the stunted root hair phenotype of other Atget lines, its heterologous expression together with the coreceptor AtGET1 rescues growth defects of Δget1get2 yeast. Ectopic expression of the cytosolic, positively charged N terminus is sufficient to block TA protein insertion in vitro. Our results collectively confirm that we have identified a plant-specific GET2 in Arabidopsis, and its sequence allows the analysis of cross-kingdom pathway conservation.
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5
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Schormann W, Hariharan S, Andrews DW. A reference library for assigning protein subcellular localizations by image-based machine learning. J Cell Biol 2020; 219:133635. [PMID: 31968357 PMCID: PMC7055006 DOI: 10.1083/jcb.201904090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/30/2019] [Accepted: 12/15/2019] [Indexed: 12/11/2022] Open
Abstract
Confocal micrographs of EGFP fusion proteins localized at key cell organelles in murine and human cells were acquired for use as subcellular localization landmarks. For each of the respective 789,011 and 523,319 optically validated cell images, morphology and statistical features were measured. Machine learning algorithms using these features permit automated assignment of the localization of other proteins and dyes in both cell types with very high accuracy. Automated assignment of subcellular localizations for model tail-anchored proteins with randomly mutated C-terminal targeting sequences allowed the discovery of motifs responsible for targeting to mitochondria, endoplasmic reticulum, and the late secretory pathway. Analysis of directed mutants enabled refinement of these motifs and characterization of protein distributions in within cellular subcompartments.
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Affiliation(s)
- Wiebke Schormann
- Biological Sciences, Sunnybrook Research Institute, Toronto, Canada
| | | | - David W Andrews
- Biological Sciences, Sunnybrook Research Institute, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada
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6
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The Molecular Basis and Biologic Significance of the β-Dystroglycan-Emerin Interaction. Int J Mol Sci 2020; 21:ijms21175944. [PMID: 32824881 PMCID: PMC7504044 DOI: 10.3390/ijms21175944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 01/04/2023] Open
Abstract
β-dystroglycan (β-DG) assembles with lamins A/C and B1 and emerin at the nuclear envelope (NE) to maintain proper nuclear architecture and function. To provide insight into the nuclear function of β-DG, we characterized the interaction between β-DG and emerin at the molecular level. Emerin is a major NE protein that regulates multiple nuclear processes and whose deficiency results in Emery–Dreifuss muscular dystrophy (EDMD). Using truncated variants of β-DG and emerin, via a series of in vitro and in vivo binding experiments and a tailored computational analysis, we determined that the β-DG–emerin interaction is mediated at least in part by their respective transmembrane domains (TM). Using surface plasmon resonance assays we showed that emerin binds to β-DG with high affinity (KD in the nanomolar range). Remarkably, the analysis of cells in which DG was knocked out demonstrated that loss of β-DG resulted in a decreased emerin stability and impairment of emerin-mediated processes. β-DG and emerin are reciprocally required for their optimal targeting within the NE, as shown by immunofluorescence, western blotting and immunoprecipitation assays using emerin variants with mutations in the TM domain and B-lymphocytes of a patient with EDMD. In summary, we demonstrated that β-DG plays a role as an emerin interacting partner modulating its stability and function.
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7
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Role of the nuclear membrane protein Emerin in front-rear polarity of the nucleus. Nat Commun 2020; 11:2122. [PMID: 32358486 PMCID: PMC7195445 DOI: 10.1038/s41467-020-15910-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 04/02/2020] [Indexed: 12/03/2022] Open
Abstract
Cell polarity refers to the intrinsic asymmetry of cells, including the orientation of the cytoskeleton. It affects cell shape and structure as well as the distribution of proteins and organelles. In migratory cells, front-rear polarity is essential and dictates movement direction. While the link between the cytoskeleton and nucleus is well-studied, we aim to investigate if front-rear polarity can be transmitted to the nucleus. We show that the knock-down of emerin, an integral protein of the nuclear envelope, abolishes preferential localization of several nuclear proteins. We propose that the frontally biased localization of the endoplasmic reticulum, through which emerin reaches the nuclear envelope, is sufficient to generate its observed bias. In primary emerin-deficient myoblasts, its expression partially rescues the polarity of the nucleus. Our results demonstrate that front-rear cell polarity is transmitted to the nucleus and that emerin is an important determinant of nuclear polarity. During cell migration, cells are polarized with distinct front vs. rear regions but whether and how polarity is transmitted to the nucleus is unclear. Here the authors show that frontally-biased endoplasmic reticulum and the nuclear membrane protein Emerin contribute to front-rear nuclear cell polarity.
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8
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Probing the Environment of Emerin by Enhanced Ascorbate Peroxidase 2 (APEX2)-Mediated Proximity Labeling. Cells 2020; 9:cells9030605. [PMID: 32138363 PMCID: PMC7140434 DOI: 10.3390/cells9030605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022] Open
Abstract
Emerin is one of the best characterized proteins of the inner nuclear membrane, but can also occur at the level of the endoplasmic reticulum. We now use enhanced ascorbate peroxidase 2 (APEX2) to probe the environment of emerin. APEX2 can be used as a genetic tag that produces short-lived yet highly reactive biotin species, allowing the modification of proteins that interact with or are in very close proximity to the tagged protein. Biotinylated proteins can be isolated using immobilized streptavidin and analyzed by mass spectrometry. As an alternative to the standard approach with a genetic fusion of APEX2 to emerin, we also used RAPIDS (rapamycin- and APEX-dependent identification of proteins by SILAC), a method with improved specificity, where the peroxidase interacts with the protein of interest (i.e., emerin) only upon addition of rapamycin to the cells. We compare these different approaches, which, together, identify well-known interaction partners of emerin like lamin A and the lamina associated polypeptide 1 (LAP1), as well as novel proximity partners.
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9
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Abstract
Due to their topology tail-anchored (TA) proteins must target to the membrane independently of the co-translational route defined by the signal sequence recognition particle (SRP), its receptor and the translocon Sec61. More than a decade of work has extensively characterized a highly conserved pathway, the yeast GET or mammalian TRC40 pathway, which is capable of countering the biogenetic challenge posed by the C-terminal TA anchor. In this review we briefly summarize current models of this targeting route and focus on emerging aspects such as the intricate interplay with the proteostatic network of cells and with other targeting pathways. Importantly, we consider the lessons provided by the in vivo analysis of the pathway in different model organisms and by the consideration of its full client spectrum in more recent studies. This analysis of the state of the field highlights directions in which the current models may be experimentally probed and conceptually extended.
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Affiliation(s)
- Nica Borgese
- Institute of Neuroscience and BIOMETRA Department, Consiglio Nazionale delle Ricerche and Università degli Studi di Milano, via Vanvitelli 32, 20129, Milan, Italy.
| | - Javier Coy-Vergara
- Department of Molecular Biology, University of Göttingen Medical Centre, Humboldtallee 23, 37073, Göttingen, Germany
| | - Sara Francesca Colombo
- Institute of Neuroscience and BIOMETRA Department, Consiglio Nazionale delle Ricerche and Università degli Studi di Milano, via Vanvitelli 32, 20129, Milan, Italy
| | - Blanche Schwappach
- Department of Molecular Biology, University of Göttingen Medical Centre, Humboldtallee 23, 37073, Göttingen, Germany.
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10
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Heller SA, Shih R, Kalra R, Kang PB. Emery-Dreifuss muscular dystrophy. Muscle Nerve 2019; 61:436-448. [PMID: 31840275 PMCID: PMC7154529 DOI: 10.1002/mus.26782] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 12/04/2019] [Accepted: 12/07/2019] [Indexed: 12/19/2022]
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a rare muscular dystrophy, but is particularly important to diagnose due to frequent life-threatening cardiac complications. EDMD classically presents with muscle weakness, early contractures, cardiac conduction abnormalities and cardiomyopathy, although the presence and severity of these manifestations vary by subtype and individual. Associated genes include EMD, LMNA, SYNE1, SYNE2, FHL1, TMEM43, SUN1, SUN2, and TTN, encoding emerin, lamin A/C, nesprin-1, nesprin-2, FHL1, LUMA, SUN1, SUN2, and titin, respectively. The Online Mendelian Inheritance in Man database recognizes subtypes 1 through 7, which captures most but not all of the associated genes. Genetic diagnosis is essential whenever available, but traditional diagnostic tools can help steer the evaluation toward EDMD and assist with interpretation of equivocal genetic test results. Management is primarily supportive, but it is important to monitor patients closely, especially for potential cardiac complications. There is a high potential for progress in the treatment of EDMD in the coming years.
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Affiliation(s)
- Scott A Heller
- Department of Neurology, University of Florida College of Medicine, Gainesville, Florida
| | - Renata Shih
- Congenital Heart Center, University of Florida College of Medicine, Gainesville, Florida
| | - Raghav Kalra
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida
| | - Peter B Kang
- Department of Neurology, University of Florida College of Medicine, Gainesville, Florida.,Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida.,Genetics Institute and Myology Institute, University of Florida, Gainesville, Florida
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11
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Casting a Wider Net: Differentiating between Inner Nuclear Envelope and Outer Nuclear Envelope Transmembrane Proteins. Int J Mol Sci 2019; 20:ijms20215248. [PMID: 31652739 PMCID: PMC6862087 DOI: 10.3390/ijms20215248] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/11/2022] Open
Abstract
The nuclear envelope (NE) surrounds the nucleus with a double membrane in eukaryotic cells. The double membranes are embedded with proteins that are synthesized on the endoplasmic reticulum and often destined specifically for either the outer nuclear membrane (ONM) or the inner nuclear membrane (INM). These nuclear envelope transmembrane proteins (NETs) play important roles in cellular function and participate in transcription, epigenetics, splicing, DNA replication, genome architecture, nuclear structure, nuclear stability, nuclear organization, and nuclear positioning. These vital functions are dependent upon both the correct localization and relative concentrations of NETs on the appropriate membrane of the NE. It is, therefore, important to understand the distribution and abundance of NETs on the NE. This review will evaluate the current tools and methodologies available to address this important topic.
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12
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James C, Müller M, Goldberg MW, Lenz C, Urlaub H, Kehlenbach RH. Proteomic mapping by rapamycin-dependent targeting of APEX2 identifies binding partners of VAPB at the inner nuclear membrane. J Biol Chem 2019; 294:16241-16254. [PMID: 31519755 DOI: 10.1074/jbc.ra118.007283] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 08/05/2019] [Indexed: 11/06/2022] Open
Abstract
Vesicle-associated membrane protein-associated protein B (VAPB) is a tail-anchored protein that is present at several contact sites of the endoplasmic reticulum (ER). We now show by immunoelectron microscopy that VAPB also localizes to the inner nuclear membrane (INM). Using a modified enhanced ascorbate peroxidase 2 (APEX2) approach with rapamycin-dependent targeting of the peroxidase to a protein of interest, we searched for proteins that are in close proximity to VAPB, particularly at the INM. In combination with stable isotope labeling with amino acids in cell culture (SILAC), we confirmed many well-known interaction partners at the level of the ER with a clear distinction between specific and nonspecific hits. Furthermore, we identified emerin, TMEM43, and ELYS as potential interaction partners of VAPB at the INM and the nuclear pore complex, respectively.
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Affiliation(s)
- Christina James
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center for Molecular Biosciences (GZMB), Georg August University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Marret Müller
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center for Molecular Biosciences (GZMB), Georg August University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Martin W Goldberg
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Christof Lenz
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center for Molecular Biosciences (GZMB), Georg August University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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13
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Verhagen JMA, van den Born M, van der Linde HC, G J Nikkels P, Verdijk RM, Kivlen MH, van Unen LMA, Baas AF, Ter Heide H, van Osch-Gevers L, Hoogeveen-Westerveld M, Herkert JC, Bertoli-Avella AM, van Slegtenhorst MA, Wessels MW, Verheijen FW, Hassel D, Hofstra RMW, Hegde RS, van Hasselt PM, van Ham TJ, van de Laar IMBH. Biallelic Variants in ASNA1, Encoding a Cytosolic Targeting Factor of Tail-Anchored Proteins, Cause Rapidly Progressive Pediatric Cardiomyopathy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 12:397-406. [PMID: 31461301 PMCID: PMC7205403 DOI: 10.1161/circgen.119.002507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Pediatric cardiomyopathies are a clinically and genetically heterogeneous group of heart muscle disorders associated with high morbidity and mortality. Although knowledge of the genetic basis of pediatric cardiomyopathy has improved considerably, the underlying cause remains elusive in a substantial proportion of cases.
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Affiliation(s)
- Judith M A Verhagen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Myrthe van den Born
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Herma C van der Linde
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Peter G J Nikkels
- Department of Pathology (P.G.J.N.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Rob M Verdijk
- Department of Pathology (R.M.V.), Erasmus MC, University Medical Center Rotterdam
| | - Maryann H Kivlen
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Leontine M A van Unen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Annette F Baas
- Department of Genetics (A.F.B.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Henriette Ter Heide
- Department of Pediatric Cardiology (H.t.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Lennie van Osch-Gevers
- Department of Pediatric Cardiology (L.v.O.-G.), Erasmus MC, University Medical Center Rotterdam
| | - Marianne Hoogeveen-Westerveld
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Johanna C Herkert
- Department of Genetics, University of Groningen, University Medical Center Groningen, the Netherlands (J.C.H.)
| | | | - Marjon A van Slegtenhorst
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Marja W Wessels
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Frans W Verheijen
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - David Hassel
- Department of Medicine III, University Hospital Heidelberg, Germany (D.H.)
| | - Robert M W Hofstra
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, United Kingdom (M.H.K., R.S.H.)
| | - Peter M van Hasselt
- Department of Pediatrics (P.M.v.H.), University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics (J.M.A.V., M.v.d.B., H.C.v.d.L., L.M.A.v.U., M.H.-W., M.A.v.S., M.W.W., F.W.V., R.M.W.H., T.J.v.H., I.M.B.H.v.d.L.), Erasmus MC, University Medical Center Rotterdam
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14
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Coy-Vergara J, Rivera-Monroy J, Urlaub H, Lenz C, Schwappach B. A trap mutant reveals the physiological client spectrum of TRC40. J Cell Sci 2019; 132:jcs.230094. [PMID: 31182645 PMCID: PMC6633398 DOI: 10.1242/jcs.230094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022] Open
Abstract
The transmembrane recognition complex (TRC) pathway targets tail-anchored (TA) proteins to the membrane of the endoplasmic reticulum (ER). While many TA proteins are known to be able to use this pathway, it is essential for the targeting of only a few. Here, we uncover a large number of TA proteins that engage with TRC40 when other targeting machineries are fully operational. We use a dominant-negative ATPase-impaired mutant of TRC40 in which aspartate 74 was replaced by a glutamate residue to trap TA proteins in the cytoplasm. Manipulation of the hydrophobic TA-binding groove in TRC40 (also known as ASNA1) reduces interaction with most, but not all, substrates suggesting that co-purification may also reflect interactions unrelated to precursor protein targeting. We confirm known TRC40 substrates and identify many additional TA proteins interacting with TRC40. By using the trap approach in combination with quantitative mass spectrometry, we show that Golgi-resident TA proteins such as the golgins golgin-84, CASP and giantin as well as the vesicle-associated membrane-protein-associated proteins VAPA and VAPB interact with TRC40. Thus, our results provide new avenues to assess the essential role of TRC40 in metazoan organisms. This article has an associated First Person interview with the first author of the paper. Summary: A strategy to decipher which tail-anchored proteins do (as opposed to can or must) use the TRC pathway in intact cells generates a comprehensive list of human TRC40 clients.
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Affiliation(s)
- Javier Coy-Vergara
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Jhon Rivera-Monroy
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen 37077, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen 37073, Germany .,Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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15
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Dharmaraj T, Guan Y, Liu J, Badens C, Gaborit B, Wilson KL. Rare BANF1 Alleles and Relatively Frequent EMD Alleles Including 'Healthy Lipid' Emerin p.D149H in the ExAC Cohort. Front Cell Dev Biol 2019; 7:48. [PMID: 31024910 PMCID: PMC6459885 DOI: 10.3389/fcell.2019.00048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 03/19/2019] [Indexed: 01/05/2023] Open
Abstract
Emerin (EMD) and barrier to autointegration factor 1 (BANF1) each bind A-type lamins (LMNA) as fundamental components of nuclear lamina structure. Mutations in LMNA, EMD and BANF1 are genetically linked to many tissue-specific disorders including Emery-Dreifuss muscular dystrophy and cardiomyopathy (LMNA, EMD), lipodystrophy, insulin resistance and type 2 diabetes (LMNA) and progeria (LMNA, BANF1). To explore human genetic variation in these genes, we analyzed EMD and BANF1 alleles in the Exome Aggregation Consortium (ExAC) cohort of 60,706 unrelated individuals. We identified 13 rare heterozygous BANF1 missense variants (p.T2S, p.H7Y, p.D9N, p.S22R, p.G25E, p.D55N, p.D57Y, p.L63P, p.N70T, p.K72R, p.R75W, p.R75Q, p.G79R), and one homozygous variant (p.D9H). Several variants are known (p.G25E) or predicted (e.g., p.D9H, p.D9N, p.L63P) to perturb BANF1 and warrant further study. Analysis of EMD revealed two previously identified variants associated with adult-onset cardiomyopathy (p.K37del, p.E35K) and one deemed 'benign' in an Emery-Dreifuss patient (p.D149H). Interestingly p.D149H was the most frequent emerin variant in ExAC, identified in 58 individuals (overall allele frequency 0.06645%), of whom 55 were East Asian (allele frequency 0.8297%). Furthermore, p.D149H associated with four 'healthy' traits: reduced triglycerides (-0.336; p = 0.0368), reduced waist circumference (-0.321; p = 0.0486), reduced cholesterol (-0.572; p = 0.000346) and reduced LDL cholesterol (-0.599; p = 0.000272). These traits are distinct from LMNA-associated metabolic disorders and provide the first insight that emerin influences metabolism. We also identified one novel in-frame deletion (p.F39del) and 62 novel emerin missense variants, many of which were relatively frequent and potentially disruptive including p.N91S and p.S143F (∼0.041% and ∼0.034% of non-Finnish Europeans, respectively), p.G156S (∼0.39% of Africans), p.R204G (∼0.18% of Latinx), p.R207P (∼0.08% of South Asians) and p.R221L (∼0.15% of Latinx). Many novel BANF1 variants are predicted to disrupt dimerization or binding to DNA, histones, emerin or A-type lamins. Many novel emerin variants are predicted to disrupt emerin filament dynamics or binding to BANF1, HDAC3, A-type lamins or other partners. These new human variants provide a foundational resource for future studies to test the molecular mechanisms of BANF1 and emerin function, and to understand the link between emerin variant p.D149H and a 'healthy' lipid profile.
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Affiliation(s)
- Tejas Dharmaraj
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Youchen Guan
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Julie Liu
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | | | | | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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16
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Targeting of LRRC59 to the Endoplasmic Reticulum and the Inner Nuclear Membrane. Int J Mol Sci 2019; 20:ijms20020334. [PMID: 30650545 PMCID: PMC6359192 DOI: 10.3390/ijms20020334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 01/12/2023] Open
Abstract
LRRC59 (leucine-rich repeat-containing protein 59) is a tail-anchored protein with a single transmembrane domain close to its C-terminal end that localizes to the endoplasmic reticulum (ER) and the nuclear envelope. Here, we investigate the mechanisms of membrane integration of LRRC59 and its targeting to the inner nuclear membrane (INM). Using purified microsomes, we show that LRRC59 can be post-translationally inserted into ER-derived membranes. The TRC-pathway, a major route for post-translational membrane insertion, is not required for LRRC59. Like emerin, another tail-anchored protein, LRRC59 reaches the INM, as demonstrated by rapamycin-dependent dimerization assays. Using different approaches to inhibit importin α/β-dependent nuclear import of soluble proteins, we show that the classic nuclear transport machinery does not play a major role in INM-targeting of LRRC59. Instead, the size of the cytoplasmic domain of LRRC59 is an important feature, suggesting that targeting is governed by passive diffusion.
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17
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Dilsaver MR, Chen P, Thompson TA, Reusser T, Mukherjee RN, Oakey J, Levy DL. Emerin induces nuclear breakage in Xenopus extract and early embryos. Mol Biol Cell 2018; 29:3155-3167. [PMID: 30332321 PMCID: PMC6340207 DOI: 10.1091/mbc.e18-05-0277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Emerin is an inner nuclear membrane protein often mutated in Emery–Dreifuss muscular dystrophy. Because emerin has diverse roles in nuclear mechanics, cytoskeletal organization, and gene expression, it has been difficult to elucidate its contribution to nuclear structure and disease pathology. In this study, we investigated emerin’s impact on nuclei assembled in Xenopus laevis egg extract, a simplified biochemical system that lacks potentially confounding cellular factors and activities. Notably, these extracts are transcriptionally inert and lack endogenous emerin and filamentous actin. Strikingly, emerin caused rupture of egg extract nuclei, dependent on the application of shear force. In egg extract, emerin localized to nonnuclear cytoplasmic membranes, and nuclear rupture was rescued by targeting emerin to the nucleus, disrupting its membrane association, or assembling nuclei with lamin A. Furthermore, emerin induced breakage of nuclei in early-stage X. laevis embryo extracts, and embryos microinjected with emerin were inviable, with ruptured nuclei. We propose that cytoplasmic membrane localization of emerin leads to rupture of nuclei that are more sensitive to mechanical perturbation, findings that may be relevant to early development and certain laminopathies.
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Affiliation(s)
- Matthew R Dilsaver
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Pan Chen
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Trey A Thompson
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Traci Reusser
- Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071
| | - Richik N Mukherjee
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - John Oakey
- Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
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18
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Chizhik AM, Ruhlandt D, Pfaff J, Karedla N, Chizhik AI, Gregor I, Kehlenbach RH, Enderlein J. Three-Dimensional Reconstruction of Nuclear Envelope Architecture Using Dual-Color Metal-Induced Energy Transfer Imaging. ACS NANO 2017; 11:11839-11846. [PMID: 28921961 DOI: 10.1021/acsnano.7b04671] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The nuclear envelope, comprising the inner and the outer nuclear membrane, separates the nucleus from the cytoplasm and plays a key role in cellular functions. Nuclear pore complexes (NPCs), which are embedded in the nuclear envelope, control transport of macromolecules between the two compartments. Here, using dual-color metal-induced energy transfer (MIET), we determine the axial distance between Lap2β and Nup358 as markers for the inner nuclear membrane and the cytoplasmic side of the NPC, respectively. Using MIET imaging, we reconstruct the 3D profile of the nuclear envelope over the whole basal area, with an axial resolution of a few nanometers. This result demonstrates that optical microscopy can achieve nanometer axial resolution in biological samples and without recourse to complex interferometric approaches.
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Affiliation(s)
- Anna M Chizhik
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
| | - Daja Ruhlandt
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
| | - Janine Pfaff
- Universitätsmedizin Göttingen, University of Göttingen, Department of Molecular Biology, GZMB , 37073 Göttingen, Germany
| | - Narain Karedla
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
| | - Alexey I Chizhik
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
| | - Ingo Gregor
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
| | - Ralph H Kehlenbach
- Universitätsmedizin Göttingen, University of Göttingen, Department of Molecular Biology, GZMB , 37073 Göttingen, Germany
| | - Jörg Enderlein
- Third Institute of Physics, University of Göttingen , 37077 Göttingen, Germany
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19
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Rivera-Monroy J, Musiol L, Unthan-Fechner K, Farkas Á, Clancy A, Coy-Vergara J, Weill U, Gockel S, Lin SY, Corey DP, Kohl T, Ströbel P, Schuldiner M, Schwappach B, Vilardi F. Mice lacking WRB reveal differential biogenesis requirements of tail-anchored proteins in vivo. Sci Rep 2016; 6:39464. [PMID: 28000760 PMCID: PMC5175141 DOI: 10.1038/srep39464] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/22/2016] [Indexed: 02/06/2023] Open
Abstract
Tail-anchored (TA) proteins are post-translationally inserted into membranes. The TRC40 pathway targets TA proteins to the endoplasmic reticulum via a receptor comprised of WRB and CAML. TRC40 pathway clients have been identified using in vitro assays, however, the relevance of the TRC40 pathway in vivo remains unknown. We followed the fate of TA proteins in two tissue-specific WRB knockout mouse models and found that their dependence on the TRC40 pathway in vitro did not predict their reaction to receptor depletion in vivo. The SNARE syntaxin 5 (Stx5) was extremely sensitive to disruption of the TRC40 pathway. Screening yeast TA proteins with mammalian homologues, we show that the particular sensitivity of Stx5 is conserved, possibly due to aggregation propensity of its cytoplasmic domain. We establish that Stx5 is an autophagy target that is inefficiently membrane-targeted by alternative pathways. Our results highlight an intimate relationship between the TRC40 pathway and cellular proteostasis.
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Affiliation(s)
- Jhon Rivera-Monroy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Lena Musiol
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Kirsten Unthan-Fechner
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Ákos Farkas
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Anne Clancy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Javier Coy-Vergara
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Gockel
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Shuh-Yow Lin
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tobias Kohl
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Philipp Ströbel
- Institute of Pathology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, D-37077, Göttingen, Germany
| | - Fabio Vilardi
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
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20
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Ott M, Marques D, Funk C, Bailer SM. Asna1/TRC40 that mediates membrane insertion of tail-anchored proteins is required for efficient release of Herpes simplex virus 1 virions. Virol J 2016; 13:175. [PMID: 27765046 PMCID: PMC5072318 DOI: 10.1186/s12985-016-0638-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/17/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Herpes simplex virus type 1 (HSV1), a member of the alphaherpesvirinae, can cause recurrent facial lesions and encephalitis. Two membrane envelopment processes, one at the inner nuclear membrane and a second at cytoplasmic membranes are crucial for a productive viral infection. Depending on the subfamily, herpesviruses encode more than 11 different transmembrane proteins including members of the tail-anchored protein family. HSV1 encodes three tail-anchored proteins pUL34, pUL56 and pUS9 characterized by a single hydrophobic region positioned at their C-terminal end that needs to be released from the ribosome prior to posttranslational membrane insertion. Asna1/TRC40 is an ATPase that targets tail-anchored proteins to the endoplasmic reticulum in a receptor-dependent manner. Cell biological data point to a critical and general role of Asna1/TRC40 in tail-anchored protein biogenesis. With this study, we aimed to determine the importance of the tail-anchored insertion machinery for HSV1 infection. METHODS To determine protein-protein interactions, the yeast-two hybrid system was applied. Asna1/TRC40 was depleted using RNA interference. Transient transfection and virus infection experiments followed by indirect immunofluorescence analysis were applied to analyse the localization of viral proteins as well as the impact of Asna1/TRC40 depletion on virus infection. RESULTS All HSV1 tail-anchored proteins specifically bound to Asna1/TRC40 but independently localized to their target membranes. While non-essential for cell viability, Asna1/TRC40 is required for efficient HSV1 replication. We show that early events of the replication cycle like virion entry and overall viral gene expression were unaffected by depletion of Asna1/TRC40. Furthermore, equal amounts of infectious virions were formed and remained cell-associated. This indicated that both nuclear egress of capsids that requires the essential tail-anchored protein pUL34, and secondary envelopment to form infectious virions were successfully completed. Despite large part of the virus life cycle proceeding normally, viral propagation was more than 10 fold reduced. We show that depletion of Asna1/TRC40 specifically affected a step late in infection during release of infectious virions to the extracellular milieu. CONCLUSIONS Asna1/TRC40 is required at a late step of herpesviral infection for efficient release of mature virions to the extracellular milieu. This study reveals novel tools to decipher exocytosis of newly formed virions as well as hitherto unknown cellular targets for antiviral therapy.
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Affiliation(s)
- Melanie Ott
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität München, Pettenkoferstr. 9a, 80336, München, Germany
| | - Débora Marques
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, Nobelstrasse 12, 70569, Stuttgart, Germany
| | - Christina Funk
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, Nobelstrasse 12, 70569, Stuttgart, Germany
| | - Susanne M Bailer
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität München, Pettenkoferstr. 9a, 80336, München, Germany. .,Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, Nobelstrasse 12, 70569, Stuttgart, Germany.
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21
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Vogl C, Panou I, Yamanbaeva G, Wichmann C, Mangosing SJ, Vilardi F, Indzhykulian AA, Pangršič T, Santarelli R, Rodriguez-Ballesteros M, Weber T, Jung S, Cardenas E, Wu X, Wojcik SM, Kwan KY, Del Castillo I, Schwappach B, Strenzke N, Corey DP, Lin SY, Moser T. Tryptophan-rich basic protein (WRB) mediates insertion of the tail-anchored protein otoferlin and is required for hair cell exocytosis and hearing. EMBO J 2016; 35:2536-2552. [PMID: 27458190 DOI: 10.15252/embj.201593565] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/29/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022] Open
Abstract
The transmembrane recognition complex (TRC40) pathway mediates the insertion of tail-anchored (TA) proteins into membranes. Here, we demonstrate that otoferlin, a TA protein essential for hair cell exocytosis, is inserted into the endoplasmic reticulum (ER) via the TRC40 pathway. We mutated the TRC40 receptor tryptophan-rich basic protein (Wrb) in hair cells of zebrafish and mice and studied the impact of defective TA protein insertion. Wrb disruption reduced otoferlin levels in hair cells and impaired hearing, which could be restored in zebrafish by transgenic Wrb rescue and otoferlin overexpression. Wrb-deficient mouse inner hair cells (IHCs) displayed normal numbers of afferent synapses, Ca2+ channels, and membrane-proximal vesicles, but contained fewer ribbon-associated vesicles. Patch-clamp of IHCs revealed impaired synaptic vesicle replenishment. In vivo recordings from postsynaptic spiral ganglion neurons showed a use-dependent reduction in sound-evoked spiking, corroborating the notion of impaired IHC vesicle replenishment. A human mutation affecting the transmembrane domain of otoferlin impaired its ER targeting and caused an auditory synaptopathy. We conclude that the TRC40 pathway is critical for hearing and propose that otoferlin is an essential substrate of this pathway in hair cells.
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Affiliation(s)
- Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Iliana Panou
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Gulnara Yamanbaeva
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - Carolin Wichmann
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sara J Mangosing
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Fabio Vilardi
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Artur A Indzhykulian
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tina Pangršič
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Physiology of Mammalian Vestibular Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Rosamaria Santarelli
- Department of Neurosciences, University of Padova, Padova, Italy.,Audiology and Phoniatrics Service, Treviso Regional Hospital, Treviso, Italy
| | | | - Thomas Weber
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sangyong Jung
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Elena Cardenas
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Xudong Wu
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Kelvin Y Kwan
- W. M. Keck Center for Collaborative Neuroscience, Nelson Lab-D250, Rutgers University, Piscataway, NJ, USA
| | - Ignacio Del Castillo
- Servicio de Genetica, Hospital Universitario Ramon y Cajal, IRYCIS, Madrid, Spain.,Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Blanche Schwappach
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Nicola Strenzke
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Shuh-Yow Lin
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany .,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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