1
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Norlin S, Axelsson J, Ericsson M, Edlund H. O304 ameliorates hyperglycemia in mice by dually promoting muscle glucose effectiveness and preserving β-cell function. Commun Biol 2023; 6:877. [PMID: 37626210 PMCID: PMC10457357 DOI: 10.1038/s42003-023-05255-6] [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: 10/04/2022] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Although insulin mediated glucose uptake in skeletal muscle is a major mechanism ensuring glucose disposal in humans, glucose effectiveness, i.e., the ability of glucose itself to stimulate its own uptake independent of insulin, accounts for roughly half of the glucose disposed during an oral glucose tolerance test. Both insulin dependent and insulin independent skeletal muscle glucose uptake are however reduced in individuals with diabetes. We here show that AMPK activator O304 stimulates insulin independent glucose uptake and utilization in skeletal muscle and heart in vivo, while preventing glycogen accumulation. Combined glucose uptake and utilization requires an increased metabolic demand and we show that O304 acts as a mitochondrial uncoupler, i.e., generates a metabolic demand. O304 averts gene expression changes associated with metabolic inflexibility in skeletal muscle and heart of diabetic mice and reverts diabetic cardiomyopathy. In Type 2 diabetes, insulin resistance elicits compensatory insulin hypersecretion, provoking β-cell stress and eventually compensatory failure. In db/db mice O304 preserves β-cell function by preventing decline in insulin secretion, β-cell mass, and pancreatic insulin content. Thus, as a dual AMPK activator and mitochondrial uncoupler O304 mitigates two central defects of T2D; impaired glucose uptake/utilization and β-cell failure, which today lack effective treatment.
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Affiliation(s)
- Stefan Norlin
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87, Umeå, Sweden
| | - Jan Axelsson
- Department of Radiation Sciences, Radiation Physics, Umeå University, SE-901 87, Umeå, Sweden
| | - Madelene Ericsson
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87, Umeå, Sweden
| | - Helena Edlund
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87, Umeå, Sweden.
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2
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Podraza-Farhanieh A, Raj D, Kao G, Naredi P. A proinsulin-dependent interaction between ENPL-1 and ASNA-1 in neurons is required to maintain insulin secretion in C. elegans. Development 2023; 150:dev201035. [PMID: 36939052 PMCID: PMC10112894 DOI: 10.1242/dev.201035] [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: 06/15/2022] [Accepted: 02/13/2023] [Indexed: 03/21/2023]
Abstract
Neuropeptides, including insulin, are important regulators of physiological functions of the organisms. Trafficking through the Golgi is crucial for the regulation of secretion of insulin-like peptides. ASNA-1 (TRC40) and ENPL-1 (GRP94) are conserved insulin secretion regulators in Caenorhabditis elegans (and mammals), and mouse Grp94 mutants display type 2 diabetes. ENPL-1/GRP94 binds proinsulin and regulates proinsulin levels in C. elegans and mammalian cells. Here, we have found that ASNA-1 and ENPL-1 cooperate to regulate insulin secretion in worms via a physical interaction that is independent of the insulin-binding site of ENPL-1. The interaction occurs in DAF-28/insulin-expressing neurons and is sensitive to changes in DAF-28 pro-peptide levels. Consistently, ASNA-1 acted in neurons to promote DAF-28/insulin secretion. The chaperone form of ASNA-1 was likely the interaction partner of ENPL-1. Loss of asna-1 disrupted Golgi trafficking pathways. ASNA-1 localization to the Golgi was affected in enpl-1 mutants and ENPL-1 overexpression partially bypassed the ASNA-1 requirement. Taken together, we find a functional interaction between ENPL-1 and ASNA-1 that is necessary to maintain proper insulin secretion in C. elegans and provides insights into how their loss might cause diabetes in mammals.
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Affiliation(s)
- Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
- Department of Surgery, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden
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3
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Raj D, Podraza-Farhanieh A, Gallego P, Kao G, Naredi P. Identification of C. elegans ASNA-1 domains and tissue requirements that differentially influence platinum sensitivity and growth control. PLoS Genet 2022; 18:e1010538. [PMID: 36480541 PMCID: PMC9803280 DOI: 10.1371/journal.pgen.1010538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 12/30/2022] [Accepted: 11/21/2022] [Indexed: 12/13/2022] Open
Abstract
ASNA1 plays an essential role in cisplatin chemotherapy response, type 2 diabetes, and heart disease. It is also an important biomarker in the treatment response of many diseases. Biochemically, ASNA1 has two mutually exclusive redox-modulated roles: a tail-anchored protein (TAP) targeting function in the reduced state and a holdase/chaperone function in the oxidized state. Assigning biochemical roles of mammalian ASNA1 to biomedical functions is crucial for successful therapy development. Our previous work showed the relevance of the C. elegans ASNA-1 homolog in modeling cisplatin response and insulin secretion. Here we analyzed two-point mutants in highly conserved residues in C. elegans ASNA-1 and determined their importance in separating the cisplatin response function from its roles in insulin secretion. asna-1(ΔHis164) and asna-1(A63V) point mutants, which both preferentially exist in the oxidized state, displayed cisplatin sensitivity phenotype as well as TAP insertion defect but not an insulin secretion defect. Further, using targeted depletion we analyzed the tissue requirements of asna-1 for C. elegans growth and development. Somatic depletion of ASNA-1 as well as simultaneous depletion of ASNA-1 in neurons and intestines resulted in an L1 arrest. We concluded that, targeting single residues in ASNA-1 affecting Switch I/Switch II domain function, in comparison to complete knockdown counteracted cisplatin resistance without jeopardizing other important biological functions. Taken together, our study shows that effects on health caused by ASNA1 mutations can have different biochemical bases.
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Affiliation(s)
- Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Pablo Gallego
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
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4
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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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5
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Tirincsi A, Sicking M, Hadzibeganovic D, Haßdenteufel S, Lang S. The Molecular Biodiversity of Protein Targeting and Protein Transport Related to the Endoplasmic Reticulum. Int J Mol Sci 2021; 23:143. [PMID: 35008565 PMCID: PMC8745461 DOI: 10.3390/ijms23010143] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
Abstract
Looking at the variety of the thousands of different polypeptides that have been focused on in the research on the endoplasmic reticulum from the last five decades taught us one humble lesson: no one size fits all. Cells use an impressive array of components to enable the safe transport of protein cargo from the cytosolic ribosomes to the endoplasmic reticulum. Safety during the transit is warranted by the interplay of cytosolic chaperones, membrane receptors, and protein translocases that together form functional networks and serve as protein targeting and translocation routes. While two targeting routes to the endoplasmic reticulum, SRP (signal recognition particle) and GET (guided entry of tail-anchored proteins), prefer targeting determinants at the N- and C-terminus of the cargo polypeptide, respectively, the recently discovered SND (SRP-independent) route seems to preferentially cater for cargos with non-generic targeting signals that are less hydrophobic or more distant from the termini. With an emphasis on targeting routes and protein translocases, we will discuss those functional networks that drive efficient protein topogenesis and shed light on their redundant and dynamic nature in health and disease.
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Affiliation(s)
- Andrea Tirincsi
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Mark Sicking
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Drazena Hadzibeganovic
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Sarah Haßdenteufel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sven Lang
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
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6
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Mehlhorn DG, Asseck LY, Grefen C. Looking for a safe haven: tail-anchored proteins and their membrane insertion pathways. PLANT PHYSIOLOGY 2021; 187:1916-1928. [PMID: 35235667 PMCID: PMC8644595 DOI: 10.1093/plphys/kiab298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/05/2021] [Indexed: 06/14/2023]
Abstract
Insertion of membrane proteins into the lipid bilayer is a crucial step during their biosynthesis. Eukaryotic cells face many challenges in directing these proteins to their predestined target membrane. The hydrophobic signal peptide or transmembrane domain (TMD) of the nascent protein must be shielded from the aqueous cytosol and its target membrane identified followed by transport and insertion. Components that evolved to deal with each of these challenging steps range from chaperones to receptors, insertases, and sophisticated translocation complexes. One prominent translocation pathway for most proteins is the signal recognition particle (SRP)-dependent pathway which mediates co-translational translocation of proteins across or into the endoplasmic reticulum (ER) membrane. This textbook example of protein insertion is stretched to its limits when faced with secretory or membrane proteins that lack an amino-terminal signal sequence or TMD. Particularly, a large group of so-called tail-anchored (TA) proteins that harbor a single carboxy-terminal TMD require an alternative, post-translational insertion route into the ER membrane. In this review, we summarize the current research in TA protein insertion with a special focus on plants, address challenges, and highlight future research avenues.
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Affiliation(s)
- Dietmar G Mehlhorn
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Lisa Y Asseck
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Christopher Grefen
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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7
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The Protein Toxins Ricin and Shiga Toxin as Tools to Explore Cellular Mechanisms of Internalization and Intracellular Transport. Toxins (Basel) 2021; 13:toxins13060377. [PMID: 34070659 PMCID: PMC8227415 DOI: 10.3390/toxins13060377] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/12/2021] [Accepted: 05/22/2021] [Indexed: 12/18/2022] Open
Abstract
Protein toxins secreted by bacteria and found in plants can be threats to human health. However, their extreme toxicity can also be exploited in different ways, e.g., to produce hybrid toxins directed against cancer cells and to study transport mechanisms in cells. Investigations during the last decades have shown how powerful these molecules are as tools in cell biological research. Here, we first present a partly historical overview, with emphasis on Shiga toxin and ricin, of how such toxins have been used to characterize processes and proteins of importance for their trafficking. In the second half of the article, we describe how one can now use toxins to investigate the role of lipid classes for intracellular transport. In recent years, it has become possible to quantify hundreds of lipid species using mass spectrometry analysis. Thus, it is also now possible to explore the importance of lipid species in intracellular transport. The detailed analyses of changes in lipids seen under conditions of inhibited toxin transport reveal previously unknown connections between syntheses of lipid classes and demonstrate the ability of cells to compensate under given conditions.
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8
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Raj D, Billing O, Podraza-Farhanieh A, Kraish B, Hemmingsson O, Kao G, Naredi P. Alternative redox forms of ASNA-1 separate insulin signaling from tail-anchored protein targeting and cisplatin resistance in C. elegans. Sci Rep 2021; 11:8678. [PMID: 33883621 PMCID: PMC8060345 DOI: 10.1038/s41598-021-88085-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 04/07/2021] [Indexed: 02/02/2023] Open
Abstract
Cisplatin is a frontline cancer therapeutic, but intrinsic or acquired resistance is common. We previously showed that cisplatin sensitivity can be achieved by inactivation of ASNA-1/TRC40 in mammalian cancer cells and in Caenorhabditis elegans. ASNA-1 has two more conserved functions: in promoting tail-anchored protein (TAP) targeting to the endoplasmic reticulum membrane and in promoting insulin secretion. However, the relation between its different functions has remained unknown. Here, we show that ASNA-1 exists in two redox states that promote TAP-targeting and insulin secretion separately. The reduced state is the one required for cisplatin resistance: an ASNA-1 point mutant, in which the protein preferentially was found in the oxidized state, was sensitive to cisplatin and defective for TAP targeting but had no insulin secretion defect. The same was true for mutants in wrb-1, which we identify as the C. elegans homolog of WRB, the ASNA1/TRC40 receptor. Finally, we uncover a previously unknown action of cisplatin induced reactive oxygen species: cisplatin induced ROS drives ASNA-1 into the oxidized form, and selectively prevents an ASNA-1-dependent TAP substrate from reaching the endoplasmic reticulum. Our work suggests that ASNA-1 acts as a redox-sensitive target for cisplatin cytotoxicity and that cisplatin resistance is likely mediated by ASNA-1-dependent TAP substrates. Treatments that promote an oxidizing tumor environment should be explored as possible means to combat cisplatin resistance.
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Affiliation(s)
- Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden
| | - Ola Billing
- Department of Surgical and Perioperative Sciences, Surgery, Umeå University, 901 85, Umeå, Sweden
| | - Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden
| | - Bashar Kraish
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden
| | - Oskar Hemmingsson
- Department of Surgical and Perioperative Sciences, Surgery, Umeå University, 901 85, Umeå, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden.
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden.
- Department of Surgery, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden.
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9
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Bone RN, Oyebamiji O, Talware S, Selvaraj S, Krishnan P, Syed F, Wu H, Evans-Molina C. A Computational Approach for Defining a Signature of β-Cell Golgi Stress in Diabetes. Diabetes 2020; 69:2364-2376. [PMID: 32820009 PMCID: PMC7576569 DOI: 10.2337/db20-0636] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/07/2020] [Indexed: 02/06/2023]
Abstract
The Golgi apparatus (GA) is an important site of insulin processing and granule maturation, but whether GA organelle dysfunction and GA stress are present in the diabetic β-cell has not been tested. We used an informatics-based approach to develop a transcriptional signature of β-cell GA stress using existing RNA sequencing and microarray data sets generated using human islets from donors with diabetes and islets where type 1 (T1D) and type 2 (T2D) diabetes had been modeled ex vivo. To narrow our results to GA-specific genes, we applied a filter set of 1,030 genes accepted as GA associated. In parallel, we generated an RNA-sequencing data set from human islets treated with brefeldin A (BFA), a known GA stress inducer. Overlapping the T1D and T2D groups with the BFA data set, we identified 120 and 204 differentially expressed genes, respectively. In both the T1D and T2D models, pathway analyses revealed that the top pathways were associated with GA integrity, organization, and trafficking. Quantitative RT-PCR was used to validate a common signature of GA stress that included ATF3, ARF4, CREB3, and COG6 Taken together, these data indicate that GA-associated genes are dysregulated in diabetes and identify putative markers of β-cell GA stress.
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Affiliation(s)
- Robert N Bone
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
| | - Olufunmilola Oyebamiji
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Sayali Talware
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Sharmila Selvaraj
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Preethi Krishnan
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Farooq Syed
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
| | - Huanmei Wu
- Department of BioHealth Informatics, Indiana University-Purdue University Indianapolis, Indianapolis, IN
| | - Carmella Evans-Molina
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
- Richard L. Roudebush VA Medical Center, Indianapolis, IN
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10
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Podraza-Farhanieh A, Natarajan B, Raj D, Kao G, Naredi P. ENPL-1, the Caenorhabditis elegans homolog of GRP94, promotes insulin secretion via regulation of proinsulin processing and maturation. Development 2020; 147:dev190082. [PMID: 33037039 PMCID: PMC10666919 DOI: 10.1242/dev.190082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 09/28/2020] [Indexed: 12/27/2022]
Abstract
Insulin/IGF signaling in Caenorhabditis elegans is crucial for proper development of the dauer larva and growth control. Mutants disturbing insulin processing, secretion and downstream signaling perturb this process and have helped identify genes that affect progression of type 2 diabetes. Insulin maturation is required for its proper secretion by pancreatic β cells. The role of the endoplasmic reticulum (ER) chaperones in insulin processing and secretion needs further study. We show that the C. elegans ER chaperone ENPL-1/GRP94 (HSP90B1), acts in dauer development by promoting insulin secretion and signaling. Processing of a proinsulin likely involves binding between the two proteins via a specific domain. We show that, in enpl-1 mutants, an unprocessed insulin exits the ER lumen and is found in dense core vesicles, but is not secreted. The high ER stress in enpl-1 mutants does not cause the secretion defect. Importantly, increased ENPL-1 levels result in increased secretion. Taken together, our work indicates that ENPL-1 operates at the level of insulin availability and is an essential modulator of insulin processing and secretion.
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Affiliation(s)
- Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | | | - Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
- Department of Surgery, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden
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11
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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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12
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Morgens DW, Chan C, Kane AJ, Weir NR, Li A, Dubreuil MM, Tsui CK, Hess GT, Lavertu A, Han K, Polyakov N, Zhou J, Handy EL, Alabi P, Dombroski A, Yao D, Altman RB, Sello JK, Denic V, Bassik MC. Retro-2 protects cells from ricin toxicity by inhibiting ASNA1-mediated ER targeting and insertion of tail-anchored proteins. eLife 2019; 8:48434. [PMID: 31674906 PMCID: PMC6858068 DOI: 10.7554/elife.48434] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
The small molecule Retro-2 prevents ricin toxicity through a poorly-defined mechanism of action (MOA), which involves halting retrograde vesicle transport to the endoplasmic reticulum (ER). CRISPRi genetic interaction analysis revealed Retro-2 activity resembles disruption of the transmembrane domain recognition complex (TRC) pathway, which mediates post-translational ER-targeting and insertion of tail-anchored (TA) proteins, including SNAREs required for retrograde transport. Cell-based and in vitro assays show that Retro-2 blocks delivery of newly-synthesized TA-proteins to the ER-targeting factor ASNA1 (TRC40). An ASNA1 point mutant identified using CRISPR-mediated mutagenesis abolishes both the cytoprotective effect of Retro-2 against ricin and its inhibitory effect on ASNA1-mediated ER-targeting. Together, our work explains how Retro-2 prevents retrograde trafficking of toxins by inhibiting TA-protein targeting, describes a general CRISPR strategy for predicting the MOA of small molecules, and paves the way for drugging the TRC pathway to treat broad classes of viruses known to be inhibited by Retro-2.
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Affiliation(s)
- David W Morgens
- Department of Genetics, Stanford University, Stanford, United States
| | - Charlene Chan
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Andrew J Kane
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Nicholas R Weir
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Amy Li
- Department of Genetics, Stanford University, Stanford, United States
| | | | - C Kimberly Tsui
- Department of Genetics, Stanford University, Stanford, United States
| | - Gaelen T Hess
- Department of Genetics, Stanford University, Stanford, United States
| | - Adam Lavertu
- Biomedical Informatics Training Program, Stanford University, Stanford, United States
| | - Kyuho Han
- Department of Genetics, Stanford University, Stanford, United States
| | - Nicole Polyakov
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Jing Zhou
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Emma L Handy
- Department of Chemistry, Brown University, Providence, United States
| | - Philip Alabi
- Department of Chemistry, Brown University, Providence, United States
| | - Amanda Dombroski
- Department of Chemistry, Brown University, Providence, United States
| | - David Yao
- Department of Genetics, Stanford University, Stanford, United States
| | - Russ B Altman
- Department of Genetics, Stanford University, Stanford, United States.,Bioengineering, Stanford University, Stanford, United States
| | - Jason K Sello
- Department of Chemistry, Brown University, Providence, United States
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Michael C Bassik
- Department of Genetics, Stanford University, Stanford, United States.,Program in Cancer Biology, Stanford University, Stanford, United States.,Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford, United States
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13
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Linders PT, Horst CVD, Beest MT, van den Bogaart G. Stx5-Mediated ER-Golgi Transport in Mammals and Yeast. Cells 2019; 8:cells8080780. [PMID: 31357511 PMCID: PMC6721632 DOI: 10.3390/cells8080780] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 01/12/2023] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 5 (Stx5) in mammals and its ortholog Sed5p in Saccharomyces cerevisiae mediate anterograde and retrograde endoplasmic reticulum (ER)-Golgi trafficking. Stx5 and Sed5p are structurally highly conserved and are both regulated by interactions with other ER-Golgi SNARE proteins, the Sec1/Munc18-like protein Scfd1/Sly1p and the membrane tethering complexes COG, p115, and GM130. Despite these similarities, yeast Sed5p and mammalian Stx5 are differently recruited to COPII-coated vesicles, and Stx5 interacts with the microtubular cytoskeleton, whereas Sed5p does not. In this review, we argue that these different Stx5 interactions contribute to structural differences in ER-Golgi transport between mammalian and yeast cells. Insight into the function of Stx5 is important given its essential role in the secretory pathway of eukaryotic cells and its involvement in infections and neurodegenerative diseases.
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Affiliation(s)
- Peter Ta Linders
- Tumor Immunology Lab, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Chiel van der Horst
- Tumor Immunology Lab, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Martin Ter Beest
- Tumor Immunology Lab, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Geert van den Bogaart
- Tumor Immunology Lab, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands.
- Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
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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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Yamaji T, Sekizuka T, Tachida Y, Sakuma C, Morimoto K, Kuroda M, Hanada K. A CRISPR Screen Identifies LAPTM4A and TM9SF Proteins as Glycolipid-Regulating Factors. iScience 2019; 11:409-424. [PMID: 30660999 PMCID: PMC6348303 DOI: 10.1016/j.isci.2018.12.039] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/13/2018] [Accepted: 12/28/2018] [Indexed: 12/02/2022] Open
Abstract
Glycosphingolipids (GSLs) are produced by various GSL-synthesizing enzymes, but post-translational regulation of these enzymes is incompletely understood. To address this knowledge disparity, we focused on biosynthesis of globotriaosylceramide (Gb3), the Shiga toxin (STx) receptor, and performed a genome-wide CRISPR/CAS9 knockout screen in HeLa cells using STx1-mediated cytotoxicity. We identified various genes including sphingolipid-related genes and membrane-trafficking genes. In addition, we found two proteins, LAPTM4A and TM9SF2, for which physiological roles remain elusive. Disruption of either LAPTM4A or TM9SF2 genes reduced Gb3 biosynthesis, resulting in accumulation of its precursor, lactosylceramide. Loss of LAPTM4A decreased endogenous Gb3 synthase activity in a post-transcriptional mechanism, whereas loss of TM9SF2 did not affect Gb3 synthase activity but instead disrupted localization of Gb3 synthase. Furthermore, the Gb3-regulating activity of TM9SF2 was conserved in the TM9SF family. These results provide mechanistic insight into the post-translational regulation of the activity and localization of Gb3 synthase. Genome-wide CRISPR knockout screening using Shiga toxin-induced cell death Both LAPTM4A and TM9SF2 are required for Gb3 biosynthesis Loss of LAPTM4A reduces Gb3 synthase activity post-transcriptionally TM9SF2 regulates the subcellular localization of Gb3 synthase
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Affiliation(s)
- Toshiyuki Yamaji
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Tsuyoshi Sekizuka
- Pathogen Genomics Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Yuriko Tachida
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Chisato Sakuma
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Kanta Morimoto
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan; Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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16
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Figueiredo Costa B, Cassella P, Colombo SF, Borgese N. Discrimination between the endoplasmic reticulum and mitochondria by spontaneously inserting tail‐anchored proteins. Traffic 2018; 19:182-197. [DOI: 10.1111/tra.12550] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Bruna Figueiredo Costa
- CNR Institute of Neuroscience and BIOMETRA DepartmentUniversità degli Studi di Milano Milan Italy
| | - Patrizia Cassella
- CNR Institute of Neuroscience and BIOMETRA DepartmentUniversità degli Studi di Milano Milan Italy
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17
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Norlin S, Parekh V, Edlund H. The ATPase activity of Asna1/TRC40 is required for pancreatic progenitor cell survival. Development 2018; 145:dev.154468. [PMID: 29180572 PMCID: PMC5825870 DOI: 10.1242/dev.154468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 11/10/2017] [Indexed: 12/13/2022]
Abstract
Asna1, also known as TRC40, is implicated in the delivery of tail-anchored (TA) proteins into the endoplasmic reticulum (ER), in vesicle-mediated transport, and in chaperoning unfolded proteins during oxidative stress/ATP depletion. Here, we show that Asna1 inactivation in pancreatic progenitor cells leads to redistribution of the Golgi TA SNARE proteins syntaxin 5 and syntaxin 6, Golgi fragmentation, and accumulation of cytosolic p62+ puncta. Asna1−/− multipotent progenitor cells (MPCs) selectively activate integrated stress response signaling and undergo apoptosis, thereby disrupting endocrine and acinar cell differentiation, resulting in pancreatic agenesis. Rescue experiments implicate the Asna1 ATPase activity and a CXXC di-cysteine motif in ensuring Golgi integrity, syntaxin 5 localization and MPC survival. Ex vivo inhibition of retrograde transport reproduces the perturbed Golgi morphology, and syntaxin 5 and syntaxin 6 expression, whereas modulation of p53 activity, using PFT-α and Nutlin-3, prevents or reproduces apoptosis in Asna1-deficient and wild-type MPCs, respectively. These findings support a role for the Asna1 ATPase activity in ensuring the survival of pancreatic MPCs, possibly by counteracting p53-mediated apoptosis. Summary: Conditional inactivation of Asna1/TRC40 in pancreatic progenitor cells results in pancreatic agenesis resulting from pancreatic progenitor cell apoptosis, thus revealing a crucial role for Asna1/TRC40 in pancreatic progenitor cell survival.
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Affiliation(s)
- Stefan Norlin
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | - Vishal Parekh
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | - Helena Edlund
- Umeå Centre for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
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18
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Haßdenteufel S, Sicking M, Schorr S, Aviram N, Fecher-Trost C, Schuldiner M, Jung M, Zimmermann R, Lang S. hSnd2 protein represents an alternative targeting factor to the endoplasmic reticulum in human cells. FEBS Lett 2017; 591:3211-3224. [PMID: 28862756 DOI: 10.1002/1873-3468.12831] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/22/2017] [Accepted: 08/24/2017] [Indexed: 12/11/2022]
Abstract
Recently, understanding of protein targeting to the endoplasmic reticulum (ER) was expanded by the discovery of multiple pathways that function in parallel to the signal recognition particle (SRP). Guided entry of tail-anchored proteins and SRP independent (SND) are two such targeting pathways described in yeast. So far, no human SND component is functionally characterized. Here, we report hSnd2 as the first constituent of the human SND pathway able to support substrate-specific protein targeting to the ER. Similar to its yeast counterpart, hSnd2 is assumed to function as a membrane-bound receptor preferentially targeting precursors carrying C-terminal transmembrane domains. Our genetic and physical interaction studies show that hSnd2 is part of a complex network of targeting and translocation that is dynamically regulated.
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Affiliation(s)
- Sarah Haßdenteufel
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Mark Sicking
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Stefan Schorr
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Naama Aviram
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Claudia Fecher-Trost
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, Homburg, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Martin Jung
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Richard Zimmermann
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Sven Lang
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
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19
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Xing S, Mehlhorn DG, Wallmeroth N, Asseck LY, Kar R, Voss A, Denninger P, Schmidt VAF, Schwarzländer M, Stierhof YD, Grossmann G, Grefen C. Loss of GET pathway orthologs in Arabidopsis thaliana causes root hair growth defects and affects SNARE abundance. Proc Natl Acad Sci U S A 2017; 114:E1544-E1553. [PMID: 28096354 PMCID: PMC5338382 DOI: 10.1073/pnas.1619525114] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are key players in cellular trafficking and coordinate vital cellular processes, such as cytokinesis, pathogen defense, and ion transport regulation. With few exceptions, SNAREs are tail-anchored (TA) proteins, bearing a C-terminal hydrophobic domain that is essential for their membrane integration. Recently, the Guided Entry of Tail-anchored proteins (GET) pathway was described in mammalian and yeast cells that serve as a blueprint of TA protein insertion [Schuldiner M, et al. (2008) Cell 134(4):634-645; Stefanovic S, Hegde RS (2007) Cell 128(6):1147-1159]. This pathway consists of six proteins, with the cytosolic ATPase GET3 chaperoning the newly synthesized TA protein posttranslationally from the ribosome to the endoplasmic reticulum (ER) membrane. Structural and biochemical insights confirmed the potential of pathway components to facilitate membrane insertion, but the physiological significance in multicellular organisms remains to be resolved. Our phylogenetic analysis of 37 GET3 orthologs from 18 different species revealed the presence of two different GET3 clades. We identified and analyzed GET pathway components in Arabidopsis thaliana and found reduced root hair elongation in Atget lines, possibly as a result of reduced SNARE biogenesis. Overexpression of AtGET3a in a receptor knockout (KO) results in severe growth defects, suggesting presence of alternative insertion pathways while highlighting an intricate involvement for the GET pathway in cellular homeostasis of plants.
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Affiliation(s)
- Shuping Xing
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Dietmar Gerald Mehlhorn
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Niklas Wallmeroth
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Lisa Yasmin Asseck
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Ritwika Kar
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Alessa Voss
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany
| | - Philipp Denninger
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Vanessa Aphaia Fiona Schmidt
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Markus Schwarzländer
- Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - York-Dieter Stierhof
- Centre for Plant Molecular Biology, Microscopy, University of Tübingen, 72076 Tuebingen, Germany
| | - Guido Grossmann
- Centre for Organismal Studies, CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Christopher Grefen
- Centre for Plant Molecular Biology, Developmental Genetics, University of Tübingen, 72076 Tuebingen, Germany;
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20
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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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21
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Bensellam M, Maxwell EL, Chan JY, Luzuriaga J, West PK, Jonas JC, Gunton JE, Laybutt DR. Hypoxia reduces ER-to-Golgi protein trafficking and increases cell death by inhibiting the adaptive unfolded protein response in mouse beta cells. Diabetologia 2016; 59:1492-1502. [PMID: 27039902 DOI: 10.1007/s00125-016-3947-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/16/2016] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Hypoxia may contribute to beta cell failure in type 2 diabetes and islet transplantation. The adaptive unfolded protein response (UPR) is required for endoplasmic reticulum (ER) homeostasis. Here we investigated whether or not hypoxia regulates the UPR in beta cells and the role the adaptive UPR plays during hypoxic stress. METHODS Mouse islets and MIN6 cells were exposed to various oxygen (O2) tensions. DNA-damage inducible transcript 3 (DDIT3), hypoxia-inducible transcription factor (HIF)1α and HSPA5 were knocked down using small interfering (si)RNA; Hspa5 was also overexpressed. db/db mice were used. RESULTS Hypoxia-response genes were upregulated in vivo in the islets of diabetic, but not prediabetic, db/db mice. In isolated mouse islets and MIN6 cells, O2 deprivation (1-5% vs 20%; 4-24 h) markedly reduced the expression of adaptive UPR genes, including Hspa5, Hsp90b1, Fkbp11 and spliced Xbp1. Coatomer protein complex genes (Copa, Cope, Copg [also known as Copg1], Copz1 and Copz2) and ER-to-Golgi protein trafficking were also reduced, whereas apoptotic genes (Ddit3, Atf3 and Trb3 [also known as Trib3]), c-Jun N-terminal kinase (JNK) phosphorylation and cell death were increased. Inhibition of JNK, but not HIF1α, restored adaptive UPR gene expression and ER-to-Golgi protein trafficking while protecting against apoptotic genes and cell death following hypoxia. DDIT3 knockdown delayed the loss of the adaptive UPR and partially protected against hypoxia-induced cell death. The latter response was prevented by HSPA5 knockdown. Finally, Hspa5 overexpression significantly protected against hypoxia-induced cell death. CONCLUSIONS/INTERPRETATION Hypoxia inhibits the adaptive UPR in beta cells via JNK and DDIT3 activation, but independently of HIF1α. Downregulation of the adaptive UPR contributes to reduced ER-to-Golgi protein trafficking and increased beta cell death during hypoxic stress.
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Affiliation(s)
- Mohammed Bensellam
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Emma L Maxwell
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jeng Yie Chan
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jude Luzuriaga
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Phillip K West
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jean-Christophe Jonas
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium
| | - Jenny E Gunton
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
- Westmead Hospital, Sydney, NSW, Australia
- The Westmead Millennium Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia.
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