1
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Yeter-Alat H, Belgareh-Touzé N, Le Saux A, Huvelle E, Mokdadi M, Banroques J, Tanner NK. The RNA Helicase Ded1 from Yeast Is Associated with the Signal Recognition Particle and Is Regulated by SRP21. Molecules 2024; 29:2944. [PMID: 38931009 PMCID: PMC11206880 DOI: 10.3390/molecules29122944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/12/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
The DEAD-box RNA helicase Ded1 is an essential yeast protein involved in translation initiation that belongs to the DDX3 subfamily. The purified Ded1 protein is an ATP-dependent RNA-binding protein and an RNA-dependent ATPase, but it was previously found to lack substrate specificity and enzymatic regulation. Here we demonstrate through yeast genetics, yeast extract pull-down experiments, in situ localization, and in vitro biochemical approaches that Ded1 is associated with, and regulated by, the signal recognition particle (SRP), which is a universally conserved ribonucleoprotein complex required for the co-translational translocation of polypeptides into the endoplasmic reticulum lumen and membrane. Ded1 is physically associated with SRP components in vivo and in vitro. Ded1 is genetically linked with SRP proteins. Finally, the enzymatic activity of Ded1 is inhibited by SRP21 in the presence of SCR1 RNA. We propose a model where Ded1 actively participates in the translocation of proteins during translation. Our results provide a new understanding of the role of Ded1 during translation.
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Affiliation(s)
- Hilal Yeter-Alat
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
| | - Naïma Belgareh-Touzé
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, UMR8226 CNRS, Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France;
| | - Agnès Le Saux
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
| | - Emmeline Huvelle
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
| | - Molka Mokdadi
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
- Laboratory of Molecular Epidemiology and Experimental Pathology, LR16IPT04, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis 1002, Tunisia
- Institut National des Sciences Appliquées et Technologies, Université de Carthage, Tunis 1080, Tunisia
| | - Josette Banroques
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
| | - N. Kyle Tanner
- Expression Génétique Microbienne, UMR8261 CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France; (H.Y.-A.); (A.L.S.); (E.H.); (M.M.); (J.B.)
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris Sciences et Lettres University, 75005 Paris, France
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2
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Lewis AJO, Zhong F, Keenan RJ, Hegde RS. Structural analysis of the dynamic ribosome-translocon complex. eLife 2024; 13:RP95814. [PMID: 38896445 PMCID: PMC11186639 DOI: 10.7554/elife.95814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024] Open
Abstract
The protein translocon at the endoplasmic reticulum comprises the Sec61 translocation channel and numerous accessory factors that collectively facilitate the biogenesis of secretory and membrane proteins. Here, we leveraged recent advances in cryo-electron microscopy (cryo-EM) and structure prediction to derive insights into several novel configurations of the ribosome-translocon complex. We show how a transmembrane domain (TMD) in a looped configuration passes through the Sec61 lateral gate during membrane insertion; how a nascent chain can bind and constrain the conformation of ribosomal protein uL22; and how the translocon-associated protein (TRAP) complex can adjust its position during different stages of protein biogenesis. Most unexpectedly, we find that a large proportion of translocon complexes contains RAMP4 intercalated into Sec61's lateral gate, widening Sec61's central pore and contributing to its hydrophilic interior. These structures lead to mechanistic hypotheses for translocon function and highlight a remarkably plastic machinery whose conformations and composition adjust dynamically to its diverse range of substrates.
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Affiliation(s)
- Aaron JO Lewis
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Frank Zhong
- Department of Molecular Genetics and Cell Biology, The University of ChicagoChicagoUnited States
| | - Robert J Keenan
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
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3
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Duart G, Graña-Montes R, Pastor-Cantizano N, Mingarro I. Experimental and computational approaches for membrane protein insertion and topology determination. Methods 2024; 226:102-119. [PMID: 38604415 DOI: 10.1016/j.ymeth.2024.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 03/13/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Abstract
Membrane proteins play pivotal roles in a wide array of cellular processes and constitute approximately a quarter of the protein-coding genes across all organisms. Despite their ubiquity and biological significance, our understanding of these proteins remains notably less comprehensive compared to their soluble counterparts. This disparity in knowledge can be attributed, in part, to the inherent challenges associated with employing specialized techniques for the investigation of membrane protein insertion and topology. This review will center on a discussion of molecular biology methodologies and computational prediction tools designed to elucidate the insertion and topology of helical membrane proteins.
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Affiliation(s)
- Gerard Duart
- Departament de Bioquímica i Biologia Molecular, Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, E-46100 Burjassot, Spain
| | - Ricardo Graña-Montes
- Departament de Bioquímica i Biologia Molecular, Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, E-46100 Burjassot, Spain
| | - Noelia Pastor-Cantizano
- Departament de Bioquímica i Biologia Molecular, Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, E-46100 Burjassot, Spain
| | - Ismael Mingarro
- Departament de Bioquímica i Biologia Molecular, Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, E-46100 Burjassot, Spain.
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4
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Zhang Y, Zhai S, Huang H, Qin S, Sun M, Chen Y, Lan X, Li G, Huang Z, Wang D, Luo Y, Xiao W, Li H, He X, Chen M, Peng X, Song X. Efficient signal sequence of mRNA vaccines enhances the antigen expression to expand the immune protection against viral infection. J Nanobiotechnology 2024; 22:295. [PMID: 38807131 PMCID: PMC11134928 DOI: 10.1186/s12951-024-02488-3] [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: 01/22/2024] [Accepted: 04/17/2024] [Indexed: 05/30/2024] Open
Abstract
The signal sequence played a crucial role in the efficacy of mRNA vaccines against virus pandemic by influencing antigen translation. However, limited research had been conducted to compare and analyze the specific mechanisms involved. In this study, a novel approach was introduced by substituting the signal sequence of the mRNA antigen to enhance its immune response. Computational simulations demonstrated that various signal peptides differed in their binding capacities with the signal recognition particle (SRP) 54 M subunit, which positively correlated with antigen translation efficiency. Our data revealed that the signal sequences of tPA and IL-6-modified receptor binding domain (RBD) mRNA vaccines sequentially led to higher antigen expression and elicited more robust humoral and cellular immune protection against the SARS-CoV-2 compared to the original signal sequence. By highlighting the importance of the signal sequence, this research provided a foundational and safe approach for ongoing modifications in signal sequence-antigen design, aiming to optimize the efficacy of mRNA vaccines.
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Affiliation(s)
- Yupei Zhang
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Songhui Zhai
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Hai Huang
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Shugang Qin
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Min Sun
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yuting Chen
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xing Lan
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Guohong Li
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zhiying Huang
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Denggang Wang
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yaoyao Luo
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wen Xiao
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Hao Li
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xi He
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Meiwan Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China.
| | - Xingchen Peng
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Xiangrong Song
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
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5
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Zhong Y, Feng J, Koh AF, Kotecha A, Greber BJ, Ataide S. Cryo-EM structure of SRP68/72 reveals an extended dimerization domain with RNA-binding activity. Nucleic Acids Res 2024; 52:5285-5300. [PMID: 38366771 PMCID: PMC11109942 DOI: 10.1093/nar/gkae107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024] Open
Abstract
The signal recognition particle (SRP) is a critical component in protein sorting pathways in all domains of life. Human SRP contains six proteins bound to the 7S RNA and their structures and functions have been mostly elucidated. The SRP68/72 dimer is the largest SRP component and is essential for SRP function. Although the structures of the SRP68/72 RNA binding and dimerization domains have been previously reported, the structure and function of large portions of the SRP68/72 dimer remain unknown. Here, we analyse full-length SRP68/72 using cryo-EM and report that SRP68/72 depend on each other for stability and form an extended dimerization domain. This newly observed dimerization domain is both a protein- and RNA-binding domain. Comparative analysis with current structural models suggests that this dimerization domain undergoes dramatic translocation upon SRP docking onto SRP receptor and eventually comes close to the Alu domain. We propose that the SRP68/72 dimerization domain functions by binding and detaching the Alu domain and SRP9/14 from the ribosomal surface, thus releasing elongation arrest upon docking onto the ER membrane.
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Affiliation(s)
- Yichen Zhong
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Junjie Feng
- Division of Structural Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Adrian F Koh
- Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, The Netherlands
| | - Abhay Kotecha
- Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, The Netherlands
| | - Basil J Greber
- Division of Structural Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Sandro F Ataide
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
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6
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Bothe A, Ban N. A highly optimized human in vitro translation system. CELL REPORTS METHODS 2024; 4:100755. [PMID: 38608690 PMCID: PMC11046033 DOI: 10.1016/j.crmeth.2024.100755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/19/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024]
Abstract
In vitro translation is an important method for studying fundamental aspects of co- and post-translational gene regulation, as well as for protein expression in the laboratory and on an industrial scale. Here, by re-examining and improving a human in vitro translation system (HITS), we were able to develop a minimal system where only four components are needed to supplement human cell lysates. Functional characterization of our improved HITS revealed the synergistic effect of mRNA capping and polyadenylation. Furthermore, we found that mRNAs are translated with an efficiency equal to or higher than existing state-of-the-art mammalian in vitro translation systems. Lastly, we present an easy preparation procedure for cytoplasmic extracts from cultured HeLa cells, which can be performed in any cell culture laboratory. These methodological advances will allow HITSs to become a widespread tool in basic molecular biology research.
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Affiliation(s)
- Adrian Bothe
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
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7
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Muthukumar G, Stevens TA, Inglis AJ, Esantsi TK, Saunders RA, Schulte F, Voorhees RM, Guna A, Weissman JS. Triaging of α-helical proteins to the mitochondrial outer membrane by distinct chaperone machinery based on substrate topology. Mol Cell 2024; 84:1101-1119.e9. [PMID: 38428433 DOI: 10.1016/j.molcel.2024.01.028] [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: 07/31/2023] [Revised: 12/08/2023] [Accepted: 01/31/2024] [Indexed: 03/03/2024]
Abstract
Mitochondrial outer membrane ⍺-helical proteins play critical roles in mitochondrial-cytoplasmic communication, but the rules governing the targeting and insertion of these biophysically diverse proteins remain unknown. Here, we first defined the complement of required mammalian biogenesis machinery through genome-wide CRISPRi screens using topologically distinct membrane proteins. Systematic analysis of nine identified factors across 21 diverse ⍺-helical substrates reveals that these components are organized into distinct targeting pathways that act on substrates based on their topology. NAC is required for the efficient targeting of polytopic proteins, whereas signal-anchored proteins require TTC1, a cytosolic chaperone that physically engages substrates. Biochemical and mutational studies reveal that TTC1 employs a conserved TPR domain and a hydrophobic groove in its C-terminal domain to support substrate solubilization and insertion into mitochondria. Thus, the targeting of diverse mitochondrial membrane proteins is achieved through topological triaging in the cytosol using principles with similarities to ER membrane protein biogenesis systems.
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Affiliation(s)
- Gayathri Muthukumar
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Taylor A Stevens
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Avenue, Pasadena, CA 91125, USA
| | - Alison J Inglis
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Avenue, Pasadena, CA 91125, USA
| | - Theodore K Esantsi
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Reuben A Saunders
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Fabian Schulte
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Avenue, Pasadena, CA 91125, USA
| | - Alina Guna
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Avenue, Pasadena, CA 91125, USA.
| | - Jonathan S Weissman
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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8
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Gamerdinger M, Deuerling E. Cotranslational sorting and processing of newly synthesized proteins in eukaryotes. Trends Biochem Sci 2024; 49:105-118. [PMID: 37919225 DOI: 10.1016/j.tibs.2023.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/28/2023] [Accepted: 10/06/2023] [Indexed: 11/04/2023]
Abstract
Ribosomes interact with a variety of different protein biogenesis factors that guide newly synthesized proteins to their native 3D shapes and cellular localization. Depending on the type of translated substrate, a distinct set of cotranslational factors must interact with the ribosome in a timely and coordinated manner to ensure proper protein biogenesis. While cytonuclear proteins require cotranslational maturation and folding factors, secretory proteins must be maintained in an unfolded state and processed cotranslationally by transport and membrane translocation factors. Here we explore the specific cotranslational processing steps for cytonuclear, secretory, and membrane proteins in eukaryotes and then discuss how the nascent polypeptide-associated complex (NAC) cotranslationally sorts these proteins into the correct protein biogenesis pathway.
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Affiliation(s)
- Martin Gamerdinger
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany.
| | - Elke Deuerling
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany.
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9
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Klein MA, Wild K, Kišonaitė M, Sinning I. Methionine aminopeptidase 2 and its autoproteolysis product have different binding sites on the ribosome. Nat Commun 2024; 15:716. [PMID: 38267453 PMCID: PMC10808355 DOI: 10.1038/s41467-024-44862-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024] Open
Abstract
Excision of the initiator methionine is among the first co-translational processes that occur at the ribosome. While this crucial step in protein maturation is executed by two types of methionine aminopeptidases in eukaryotes (MAP1 and MAP2), additional roles in disease and translational regulation have drawn more attention to MAP2. Here, we report several cryo-EM structures of human and fungal MAP2 at the 80S ribosome. Irrespective of nascent chains, MAP2 can occupy the tunnel exit. On nascent chain displaying ribosomes, the MAP2-80S interaction is highly dynamic and the MAP2-specific N-terminal extension engages in stabilizing interactions with the long rRNA expansion segment ES27L. Loss of this extension by autoproteolytic cleavage impedes interactions at the tunnel, while promoting MAP2 to enter the ribosomal A-site, where it engages with crucial functional centers of translation. These findings reveal that proteolytic remodeling of MAP2 severely affects ribosome binding, and set the stage for targeted functional studies.
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Affiliation(s)
- Marius A Klein
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Miglė Kišonaitė
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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10
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Stevens TA, Tomaleri GP, Hazu M, Wei S, Nguyen VN, DeKalb C, Voorhees RM, Pleiner T. A nanobody-based strategy for rapid and scalable purification of human protein complexes. Nat Protoc 2024; 19:127-158. [PMID: 37974029 DOI: 10.1038/s41596-023-00904-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 08/18/2023] [Indexed: 11/19/2023]
Abstract
The isolation of proteins in high yield and purity is a major bottleneck for the analysis of their three-dimensional structure, function and interactome. Here, we present a streamlined workflow for the rapid production of proteins or protein complexes using lentiviral transduction of human suspension cells, combined with highly specific nanobody-mediated purification and proteolytic elution. Application of the method requires prior generation of a plasmid coding for a protein of interest (POI) fused to an N- or C-terminal GFP or ALFA peptide tag using a lentiviral plasmid toolkit we have designed. The plasmid is then used to generate human suspension cell lines stably expressing the tagged fusion protein by lentiviral transduction. By leveraging the picomolar affinity of the GFP and ALFA nanobodies for their respective tags, the POI can be specifically captured from the resulting cell lysate even when expressed at low levels and under a variety of conditions, including detergents and mild denaturants. Finally, rapid and specific elution of the POI (in its tagged or untagged form) under native conditions is achieved within minutes at 4 °C, using the engineered SUMO protease SENPEuB. We demonstrate the wide applicability of the method by purifying multiple challenging soluble and membrane protein complexes to high purity from human cells. Our strategy is also directly compatible with many widely used GFP-expression plasmids, cell lines and transgenic model organisms. Finally, our method is faster than alternative approaches, requiring only 8 d from plasmid to purified protein, and results in substantially improved yields and purity.
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Affiliation(s)
- Taylor Anthony Stevens
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Giovani Pinton Tomaleri
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Masami Hazu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sophia Wei
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Vy N Nguyen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Charlene DeKalb
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Tino Pleiner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
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11
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Ronayne CT, Jackson TD, Bennett CF, Perry EA, Kantorovic N, Puigserver P. Tetracyclines activate mitoribosome quality control and reduce ER stress to promote cell survival. EMBO Rep 2023; 24:e57228. [PMID: 37818824 DOI: 10.15252/embr.202357228] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
Mitochondrial diseases are a group of disorders defined by defects in oxidative phosphorylation caused by nuclear- or mitochondrial-encoded gene mutations. A main cellular phenotype of mitochondrial disease mutations is redox imbalances and inflammatory signaling underlying pathogenic signatures of these patients. One method to rescue this cell death vulnerability is the inhibition of mitochondrial translation using tetracyclines. However, the mechanisms whereby tetracyclines promote cell survival are unknown. Here, we show that tetracyclines inhibit the mitochondrial ribosome and promote survival through suppression of endoplasmic reticulum (ER) stress. Tetracyclines increase mitochondrial levels of the mitoribosome quality control factor MALSU1 (Mitochondrial Assembly of Ribosomal Large Subunit 1) and promote its recruitment to the mitoribosome large subunit, where MALSU1 is necessary for tetracycline-induced survival and suppression of ER stress. Glucose starvation induces ER stress to activate the unfolded protein response and IRE1α-mediated cell death that is inhibited by tetracyclines. These studies establish a new interorganelle communication whereby inhibition of the mitoribosome signals to the ER to promote survival, implicating basic mechanisms of cell survival and treatment of mitochondrial diseases.
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Affiliation(s)
- Conor T Ronayne
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Thomas D Jackson
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Christopher F Bennett
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Elizabeth A Perry
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Noa Kantorovic
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
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12
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Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
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Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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13
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Gamerdinger M, Jia M, Schloemer R, Rabl L, Jaskolowski M, Khakzar KM, Ulusoy Z, Wallisch A, Jomaa A, Hunaeus G, Scaiola A, Diederichs K, Ban N, Deuerling E. NAC controls cotranslational N-terminal methionine excision in eukaryotes. Science 2023; 380:1238-1243. [PMID: 37347872 DOI: 10.1126/science.adg3297] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/18/2023] [Indexed: 06/24/2023]
Abstract
N-terminal methionine excision from newly synthesized proteins, catalyzed cotranslationally by methionine aminopeptidases (METAPs), is an essential and universally conserved process that plays a key role in cell homeostasis and protein biogenesis. However, how METAPs interact with ribosomes and how their cleavage specificity is ensured is unknown. We discovered that in eukaryotes the nascent polypeptide-associated complex (NAC) controls ribosome binding of METAP1. NAC recruits METAP1 using a long, flexible tail and provides a platform for the formation of an active methionine excision complex at the ribosomal tunnel exit. This mode of interaction ensures the efficient excision of methionine from cytosolic proteins, whereas proteins targeted to the endoplasmic reticulum are spared. Our results suggest a broader mechanism for how access of protein biogenesis factors to translating ribosomes is controlled.
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Affiliation(s)
- Martin Gamerdinger
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Min Jia
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Renate Schloemer
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Laurenz Rabl
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Mateusz Jaskolowski
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Katrin M Khakzar
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Zeynel Ulusoy
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Annalena Wallisch
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Gundula Hunaeus
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Kay Diederichs
- Department of Biology, Molecular Bioinformatics, University of Konstanz, 78457 Konstanz, Germany
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Elke Deuerling
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
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14
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Ronayne CT, Bennett CF, Perry EA, Kantorovich N, Puigserver P. Tetracycline-dependent inhibition of mitoribosome protein elongation in mitochondrial disease mutant cells suppresses IRE1α to promote cell survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.09.531795. [PMID: 36945631 PMCID: PMC10028993 DOI: 10.1101/2023.03.09.531795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Mitochondrial diseases are a group of disorders defined by defects in oxidative phosphorylation caused by nuclear- or mitochondrial-encoded gene mutations. A main cellular phenotype of mitochondrial disease mutations are redox imbalances and inflammatory signaling underlying pathogenic signatures of these patients. Depending on the type of mitochondrial mutation, certain mechanisms can efficiently rescue cell death vulnerability. One method is the inhibition of mitochondrial translation elongation using tetracyclines, potent suppressors of cell death in mitochondrial disease mutant cells. However, the mechanisms whereby tetracyclines promote cell survival are unknown. Here, we show that in mitochondrial mutant disease cells, tetracycline-mediated inhibition of mitoribosome elongation promotes survival through suppression of the ER stress IRE1α protein. Tetracyclines increased levels of the splitting factor MALSU1 (Mitochondrial Assembly of Ribosomal Large Subunit 1) at the mitochondria with recruitment to the mitochondrial ribosome (mitoribosome) large subunit. MALSU1, but not other quality control factors, was required for tetracycline-induced cell survival in mitochondrial disease mutant cells during glucose starvation. In these cells, nutrient stress induced cell death through IRE1α activation associated with a strong protein loading in the ER lumen. Notably, tetracyclines rescued cell death through suppression of IRE1α oligomerization and activity. Consistent with MALSU1 requirement, MALSU1 deficient mitochondrial mutant cells were sensitive to glucose-deprivation and exhibited increased ER stress and activation of IRE1α that was not reversed by tetracyclines. These studies show that inhibition of mitoribosome elongation signals to the ER to promote survival, establishing a new interorganelle communication between the mitoribosome and ER with implications in basic mechanisms of cell survival and treatment of mitochondrial diseases.
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15
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Pauwels E, Shewakramani NR, De Wijngaert B, Camps A, Provinciael B, Stroobants J, Kalies KU, Hartmann E, Maes P, Vermeire K, Das K. Structural insights into TRAP association with ribosome-Sec61 complex and translocon inhibition by a CADA derivative. SCIENCE ADVANCES 2023; 9:eadf0797. [PMID: 36867692 PMCID: PMC9984176 DOI: 10.1126/sciadv.adf0797] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/31/2023] [Indexed: 05/26/2023]
Abstract
During cotranslational translocation, the signal peptide of a nascent chain binds Sec61 translocon to initiate protein transport through the endoplasmic reticulum (ER) membrane. Our cryo-electron microscopy structure of ribosome-Sec61 shows binding of an ordered heterotetrameric translocon-associated protein (TRAP) complex, in which TRAP-γ is anchored at two adjacent positions of 28S ribosomal RNA and interacts with ribosomal protein L38 and Sec61α/γ. Four transmembrane helices (TMHs) of TRAP-γ cluster with one C-terminal helix of each α, β, and δ subunits. The seven TMH bundle helps position a crescent-shaped trimeric TRAP-α/β/δ core in the ER lumen, facing the Sec61 channel. Further, our in vitro assay establishes the cyclotriazadisulfonamide derivative CK147 as a translocon inhibitor. A structure of ribosome-Sec61-CK147 reveals CK147 binding the channel and interacting with the plug helix from the lumenal side. The CK147 resistance mutations surround the inhibitor. These structures help in understanding the TRAP functions and provide a new Sec61 site for designing translocon inhibitors.
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Affiliation(s)
- Eva Pauwels
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Neesha R. Shewakramani
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Brent De Wijngaert
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Anita Camps
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Becky Provinciael
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Joren Stroobants
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Kai-Uwe Kalies
- Centre for Structural and Cell Biology in Medicine, Institute of Biology, University of Lübeck, Lübeck 23562, Germany
| | - Enno Hartmann
- Centre for Structural and Cell Biology in Medicine, Institute of Biology, University of Lübeck, Lübeck 23562, Germany
| | - Piet Maes
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Clinical and Epidemiological Virology, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Kurt Vermeire
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
| | - Kalyan Das
- Department of Microbiology, Immunology, and Transplantation, KU Leuven, Leuven 3000, Belgium
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven 3000, Belgium
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16
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McKenna MJ, Shao S. The Endoplasmic Reticulum and the Fidelity of Nascent Protein Localization. Cold Spring Harb Perspect Biol 2023; 15:a041249. [PMID: 36041782 PMCID: PMC9979852 DOI: 10.1101/cshperspect.a041249] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
High-fidelity protein localization is essential to define the identities and functions of different organelles and to maintain cellular homeostasis. Accurate localization of nascent proteins requires specific protein targeting pathways as well as quality control (QC) mechanisms to remove mislocalized proteins. The endoplasmic reticulum (ER) is the first destination for approximately one-third of the eukaryotic proteome and a major site of protein biosynthesis and QC. In mammalian cells, trafficking from the ER provides nascent proteins access to the extracellular space and essentially every cellular membrane and organelle except for mitochondria and possibly peroxisomes. Here, we discuss the biosynthetic mechanisms that deliver nascent proteins to the ER and the QC mechanisms that interface with the ER to correct or degrade mislocalized proteins.
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Affiliation(s)
- Michael J McKenna
- Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts 02115, USA
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts 02115, USA
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17
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Sun S, Li X, Mariappan M. Signal sequences encode information for protein folding in the endoplasmic reticulum. J Cell Biol 2023; 222:213733. [PMID: 36459117 PMCID: PMC9723807 DOI: 10.1083/jcb.202203070] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 09/22/2022] [Accepted: 10/26/2022] [Indexed: 12/05/2022] Open
Abstract
One-third of newly synthesized proteins in mammals are translocated into the endoplasmic reticulum (ER) through the Sec61 translocon. How protein translocation coordinates with chaperone availability in the ER to promote protein folding remains unclear. We find that marginally hydrophobic signal sequences and transmembrane domains cause transient retention at the Sec61 translocon and require the luminal BiP chaperone for efficient protein translocation. Using a substrate-trapping proteomic approach, we identify that nascent proteins bearing marginally hydrophobic signal sequences accumulate on the cytosolic side of the Sec61 translocon. Sec63 is co-translationally recruited to the translocation site and mediates BiP binding to incoming polypeptides. BiP binding not only releases translocationally paused nascent chains but also ensures protein folding in the ER. Increasing hydrophobicity of signal sequences bypasses Sec63/BiP-dependent translocation, but translocated proteins are prone to misfold and aggregate in the ER under limited BiP availability. Thus, the signal sequence-guided protein folding may explain why signal sequences are diverse and use multiple protein translocation pathways.
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Affiliation(s)
- Sha Sun
- Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, CT
| | - Xia Li
- Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, CT
| | - Malaiyalam Mariappan
- Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, CT
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18
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O'Keefe S, Pool MR, High S. Membrane protein biogenesis at the ER: the highways and byways. FEBS J 2022; 289:6835-6862. [PMID: 33960686 DOI: 10.1111/febs.15905] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 01/13/2023]
Abstract
The Sec61 complex is the major protein translocation channel of the endoplasmic reticulum (ER), where it plays a central role in the biogenesis of membrane and secretory proteins. Whilst Sec61-mediated protein translocation is typically coupled to polypeptide synthesis, suggestive of significant complexity, an obvious characteristic of this core translocation machinery is its surprising simplicity. Over thirty years after its initial discovery, we now understand that the Sec61 complex is in fact the central piece of an elaborate jigsaw puzzle, which can be partly solved using new research findings. We propose that the Sec61 complex acts as a dynamic hub for co-translational protein translocation at the ER, proactively recruiting a range of accessory complexes that enhance and regulate its function in response to different protein clients. It is now clear that the Sec61 complex does not have a monopoly on co-translational insertion, with some transmembrane proteins preferentially utilising the ER membrane complex instead. We also have a better understanding of post-insertion events, where at least one membrane-embedded chaperone complex can capture the newly inserted transmembrane domains of multi-span proteins and co-ordinate their assembly into a native structure. Having discovered this array of Sec61-associated components and competitors, our next challenge is to understand how they act together in order to expand the range and complexity of the membrane proteins that can be synthesised at the ER. Furthermore, this diversity of components and pathways may open up new opportunities for targeted therapeutic interventions designed to selectively modulate protein biogenesis at the ER.
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Affiliation(s)
- Sarah O'Keefe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Martin R Pool
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Stephen High
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
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19
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Tirincsi A, O’Keefe S, Nguyen D, Sicking M, Dudek J, Förster F, Jung M, Hadzibeganovic D, Helms V, High S, Zimmermann R, Lang S. Proteomics Identifies Substrates and a Novel Component in hSnd2-Dependent ER Protein Targeting. Cells 2022; 11:cells11182925. [PMID: 36139500 PMCID: PMC9496750 DOI: 10.3390/cells11182925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/07/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Importing proteins into the endoplasmic reticulum (ER) is essential for about 30% of the human proteome. It involves the targeting of precursor proteins to the ER and their insertion into or translocation across the ER membrane. Furthermore, it relies on signals in the precursor polypeptides and components, which read the signals and facilitate their targeting to a protein-conducting channel in the ER membrane, the Sec61 complex. Compared to the SRP- and TRC-dependent pathways, little is known about the SRP-independent/SND pathway. Our aim was to identify additional components and characterize the client spectrum of the human SND pathway. The established strategy of combining the depletion of the central hSnd2 component from HeLa cells with proteomic and differential protein abundance analysis was used. The SRP and TRC targeting pathways were analyzed in comparison. TMEM109 was characterized as hSnd3. Unlike SRP but similar to TRC, the SND clients are predominantly membrane proteins with N-terminal, central, or C-terminal targeting signals.
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Affiliation(s)
- Andrea Tirincsi
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Sarah O’Keefe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Duy Nguyen
- Center for Bioinformatics, Saarland University, 66041 Saarbrücken, Germany
| | - Mark Sicking
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Johanna Dudek
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Friedrich Förster
- Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Martin Jung
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | | | - Volkhard Helms
- Center for Bioinformatics, Saarland University, 66041 Saarbrücken, Germany
| | - Stephen High
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
- Correspondence: (R.Z.); (S.L.)
| | - Sven Lang
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
- Correspondence: (R.Z.); (S.L.)
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20
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Zinnall U, Milek M, Minia I, Vieira-Vieira CH, Müller S, Mastrobuoni G, Hazapis OG, Del Giudice S, Schwefel D, Bley N, Voigt F, Chao JA, Kempa S, Hüttelmaier S, Selbach M, Landthaler M. HDLBP binds ER-targeted mRNAs by multivalent interactions to promote protein synthesis of transmembrane and secreted proteins. Nat Commun 2022; 13:2727. [PMID: 35585045 PMCID: PMC9117268 DOI: 10.1038/s41467-022-30322-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 04/13/2022] [Indexed: 01/09/2023] Open
Abstract
The biological role of RNA-binding proteins in the secretory pathway is not well established. Here, we describe that human HDLBP/Vigilin directly interacts with more than 80% of ER-localized mRNAs. PAR-CLIP analysis reveals that these transcripts represent high affinity HDLBP substrates and are specifically bound in their coding sequences (CDS), in contrast to CDS/3’UTR-bound cytosolic mRNAs. HDLBP crosslinks strongly to long CU-rich motifs, which frequently reside in CDS of ER-localized mRNAs and result in high affinity multivalent interactions. In addition to HDLBP-ncRNA interactome, quantification of HDLBP-proximal proteome confirms association with components of the translational apparatus and the signal recognition particle. Absence of HDLBP results in decreased translation efficiency of HDLBP target mRNAs, impaired protein synthesis and secretion in model cell lines, as well as decreased tumor growth in a lung cancer mouse model. These results highlight a general function for HDLBP in the translation of ER-localized mRNAs and its relevance for tumor progression. RNA binding protein HDLBP (or Vigilin) localizes in the endoplasmic reticulum (ER) membrane. Here the authors show that HDLBP contributes to translation of ER-targeted mRNAs.
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Affiliation(s)
- Ulrike Zinnall
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Miha Milek
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany. .,National Institute of Chemistry, Ljubljana, Slovenia. .,Core Unit Bioinformatics, Berlin Institute of Health at Charité, Berlin, Germany.
| | - Igor Minia
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Carlos H Vieira-Vieira
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Simon Müller
- Institute of Molecular Medicine, Medical Faculty, Martin Luther University, Halle, Germany
| | - Guido Mastrobuoni
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Orsalia-Georgia Hazapis
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Simone Del Giudice
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - David Schwefel
- Charite-Universitätsmedizin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Nadine Bley
- Institute of Molecular Medicine, Medical Faculty, Martin Luther University, Halle, Germany
| | - Franka Voigt
- Friedrich Miescher Institute for Biomedical Research, 4058, Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, 4058, Basel, Switzerland
| | - Stefan Kempa
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Stefan Hüttelmaier
- Institute of Molecular Medicine, Medical Faculty, Martin Luther University, Halle, Germany
| | - Matthias Selbach
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany.,Charite-Universitätsmedizin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Markus Landthaler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany. .,IRI Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany.
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21
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Pool MR. Targeting of Proteins for Translocation at the Endoplasmic Reticulum. Int J Mol Sci 2022; 23:ijms23073773. [PMID: 35409131 PMCID: PMC8998515 DOI: 10.3390/ijms23073773] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 12/12/2022] Open
Abstract
The endoplasmic reticulum represents the gateway to the secretory pathway. Here, proteins destined for secretion, as well as soluble and membrane proteins that reside in the endomembrane system and plasma membrane, are triaged from proteins that will remain in the cytosol or be targeted to other cellular organelles. This process requires the faithful recognition of specific targeting signals and subsequent delivery mechanisms to then target them to the translocases present at the ER membrane, which can either translocate them into the ER lumen or insert them into the lipid bilayer. This review focuses on the current understanding of the first step in this process representing the targeting phase. Targeting is typically mediated by cleavable N-terminal hydrophobic signal sequences or internal membrane anchor sequences; these can either be captured co-translationally at the ribosome or recognised post-translationally and then delivered to the ER translocases. Location and features of the targeting sequence dictate which of several overlapping targeting pathway substrates will be used. Mutations in the targeting machinery or targeting signals can be linked to diseases.
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Affiliation(s)
- Martin R Pool
- School of Biological Science, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
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22
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Jomaa A, Gamerdinger M, Hsieh HH, Wallisch A, Chandrasekaran V, Ulusoy Z, Scaiola A, Hegde RS, Shan SO, Ban N, Deuerling E. Mechanism of signal sequence handover from NAC to SRP on ribosomes during ER-protein targeting. Science 2022; 375:839-844. [PMID: 35201867 PMCID: PMC7612438 DOI: 10.1126/science.abl6459] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The nascent polypeptide-associated complex (NAC) interacts with newly synthesized proteins at the ribosomal tunnel exit and competes with the signal recognition particle (SRP) to prevent mistargeting of cytosolic and mitochondrial polypeptides to the endoplasmic reticulum (ER). How NAC antagonizes SRP and how this is overcome by ER targeting signals are unknown. Here, we found that NAC uses two domains with opposing effects to control SRP access. The core globular domain prevented SRP from binding to signal-less ribosomes, whereas a flexibly attached domain transiently captured SRP to permit scanning of nascent chains. The emergence of an ER-targeting signal destabilized NAC's globular domain and facilitated SRP access to the nascent chain. These findings elucidate how NAC hands over the signal sequence to SRP and imparts specificity of protein localization.
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Affiliation(s)
- Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Martin Gamerdinger
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Hao-Hsuan Hsieh
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Annalena Wallisch
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Zeynel Ulusoy
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Shu-ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Elke Deuerling
- Department of Biology, Molecular Microbiology, University of Konstanz, 78457 Konstanz, Germany
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23
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Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun 2022; 13:1069. [PMID: 35217658 PMCID: PMC8881573 DOI: 10.1038/s41467-022-28675-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 02/07/2022] [Indexed: 11/08/2022] Open
Abstract
The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli. Bacterial responses to nutrient limitation and other stress conditions are often modulated by the nucleotide-based second messenger (p)ppGpp. Here, the authors show that (p)ppGpp inhibits the SRP membrane-protein insertion and secretion pathway by binding to GTPases Ffh and FtsY.
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Hegde RS, Keenan RJ. The mechanisms of integral membrane protein biogenesis. Nat Rev Mol Cell Biol 2022; 23:107-124. [PMID: 34556847 DOI: 10.1038/s41580-021-00413-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2021] [Indexed: 02/08/2023]
Abstract
Roughly one quarter of all genes code for integral membrane proteins that are inserted into the plasma membrane of prokaryotes or the endoplasmic reticulum membrane of eukaryotes. Multiple pathways are used for the targeting and insertion of membrane proteins on the basis of their topological and biophysical characteristics. Multipass membrane proteins span the membrane multiple times and face the additional challenges of intramembrane folding. In many cases, integral membrane proteins require assembly with other proteins to form multi-subunit membrane protein complexes. Recent biochemical and structural analyses have provided considerable clarity regarding the molecular basis of membrane protein targeting and insertion, with tantalizing new insights into the poorly understood processes of multipass membrane protein biogenesis and multi-subunit protein complex assembly.
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Affiliation(s)
- Ramanujan S Hegde
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
| | - Robert J Keenan
- Gordon Center for Integrative Science, The University of Chicago, Chicago, IL, USA.
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25
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Kišonaitė M, Wild K, Lapouge K, Ruppert T, Sinning I. High-resolution structures of a thermophilic eukaryotic 80S ribosome reveal atomistic details of translocation. Nat Commun 2022; 13:476. [PMID: 35079002 PMCID: PMC8789840 DOI: 10.1038/s41467-022-27967-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 01/02/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractRibosomes are complex and highly conserved ribonucleoprotein assemblies catalyzing protein biosynthesis in every organism. Here we present high-resolution cryo-EM structures of the 80S ribosome from a thermophilic fungus in two rotational states, which due to increased 80S stability provide a number of mechanistic details of eukaryotic translation. We identify a universally conserved ‘nested base-triple knot’ in the 26S rRNA at the polypeptide tunnel exit with a bulged-out nucleotide that likely serves as an adaptable element for nascent chain containment and handover. We visualize the structure and dynamics of the ribosome protective factor Stm1 upon ribosomal 40S head swiveling. We describe the structural impact of a unique and essential m1acp3 Ψ 18S rRNA hyper-modification embracing the anticodon wobble-position for eukaryotic tRNA and mRNA translocation. We complete the eEF2-GTPase switch cycle describing the GDP-bound post-hydrolysis state. Taken together, our data and their integration into the structural landscape of 80S ribosomes furthers our understanding of protein biogenesis.
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Hsieh HH, Shan SO. Fidelity of Cotranslational Protein Targeting to the Endoplasmic Reticulum. Int J Mol Sci 2021; 23:ijms23010281. [PMID: 35008707 PMCID: PMC8745203 DOI: 10.3390/ijms23010281] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 02/04/2023] Open
Abstract
Fidelity of protein targeting is essential for the proper biogenesis and functioning of organelles. Unlike replication, transcription and translation processes, in which multiple mechanisms to recognize and reject noncognate substrates are established in energetic and molecular detail, the mechanisms by which cells achieve a high fidelity in protein localization remain incompletely understood. Signal recognition particle (SRP), a conserved pathway to mediate the localization of membrane and secretory proteins to the appropriate cellular membrane, provides a paradigm to understand the molecular basis of protein localization in the cell. In this chapter, we review recent progress in deciphering the molecular mechanisms and substrate selection of the mammalian SRP pathway, with an emphasis on the key role of the cotranslational chaperone NAC in preventing protein mistargeting to the ER and in ensuring the organelle specificity of protein localization.
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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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28
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Svitkin YV, Gingras AC, Sonenberg N. Membrane-dependent relief of translation elongation arrest on pseudouridine- and N1-methyl-pseudouridine-modified mRNAs. Nucleic Acids Res 2021; 50:7202-7215. [PMID: 34933339 PMCID: PMC9303281 DOI: 10.1093/nar/gkab1241] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/12/2021] [Accepted: 12/03/2021] [Indexed: 11/13/2022] Open
Abstract
Expression of therapeutically important proteins has benefited dramatically from the advent of chemically modified mRNAs that feature decreased lability and immunogenicity. This had a momentous effect on the rapid development of COVID-19 mRNA vaccines. Incorporation of the naturally occurring pseudouridine (Ψ) or N1-methyl-pseudouridine (N1mΨ) into in vitro transcribed mRNAs prevents the activation of unwanted immune responses by blocking eIF2α phosphorylation, which inhibits translation. Here, we report that Ψs in luciferase (Luc) mRNA exacerbate translation pausing in nuclease-untreated rabbit reticulocyte lysate (uRRL) and promote the formation of high-order-ribosome structures. The major deceleration of elongation occurs at the Ψ-rich nucleotides 1294-1326 of Ψ-Luc mRNA and results in premature termination of translation. The impairment of translation is mainly due to the shortage of membranous components. Supplementing uRRL with canine microsomal membranes (CMMs) relaxes the impediments to ribosome movement, resolves collided ribosomes, and greatly enhances full-size luciferase production. CMMs also strongly stimulated an extremely inefficient translation of N1mΨ-Luc mRNA in uRRL. Evidence is presented that translational pausing can promote membrane recruitment of polysomes with nascent polypeptides that lack a signal sequence. Our results highlight an underappreciated role of membrane binding to polysomes in the prevention of ribosome collision and premature release of nascent polypeptides.
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Affiliation(s)
- Yuri V Svitkin
- Department of Biochemistry, McGill University, Montréal, Québec H3A 1A3, Canada.,Rosalind and Morris Goodman Cancer Institute, Montréal, Québec H3A 1A3, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1×5, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal, Québec H3A 1A3, Canada.,Rosalind and Morris Goodman Cancer Institute, Montréal, Québec H3A 1A3, Canada
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29
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Inhibitors of the Sec61 Complex and Novel High Throughput Screening Strategies to Target the Protein Translocation Pathway. Int J Mol Sci 2021; 22:ijms222112007. [PMID: 34769437 PMCID: PMC8585047 DOI: 10.3390/ijms222112007] [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: 09/30/2021] [Revised: 10/25/2021] [Accepted: 10/29/2021] [Indexed: 02/08/2023] Open
Abstract
Proteins targeted to the secretory pathway start their intracellular journey by being transported across biological membranes such as the endoplasmic reticulum (ER). A central component in this protein translocation process across the ER is the Sec61 translocon complex, which is only intracellularly expressed and does not have any enzymatic activity. In addition, Sec61 translocon complexes are difficult to purify and to reconstitute. Screening for small molecule inhibitors impairing its function has thus been notoriously difficult. However, such translocation inhibitors may not only be valuable tools for cell biology, but may also represent novel anticancer drugs, given that cancer cells heavily depend on efficient protein translocation into the ER to support their fast growth. In this review, different inhibitors of protein translocation will be discussed, and their specific mode of action will be compared. In addition, recently published screening strategies for small molecule inhibitors targeting the whole SRP-Sec61 targeting/translocation pathway will be summarized. Of note, slightly modified assays may be used in the future to screen for substances affecting SecYEG, the bacterial ortholog of the Sec61 complex, in order to identify novel antibiotic drugs.
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30
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Take Me Home, Protein Roads: Structural Insights into Signal Peptide Interactions during ER Translocation. Int J Mol Sci 2021; 22:ijms222111871. [PMID: 34769302 PMCID: PMC8584900 DOI: 10.3390/ijms222111871] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/14/2021] [Accepted: 10/28/2021] [Indexed: 11/17/2022] Open
Abstract
Cleavable endoplasmic reticulum (ER) signal peptides (SPs) and other non-cleavable signal sequences target roughly a quarter of the human proteome to the ER. These short peptides, mostly located at the N-termini of proteins, are highly diverse. For most proteins targeted to the ER, it is the interactions between the signal sequences and the various ER targeting and translocation machineries such as the signal recognition particle (SRP), the protein-conducting channel Sec61, and the signal peptidase complex (SPC) that determine the proteins’ target location and provide translocation fidelity. In this review, we follow the signal peptide into the ER and discuss the recent insights that structural biology has provided on the governing principles of those interactions.
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31
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Weber R, Chung MY, Keskeny C, Zinnall U, Landthaler M, Valkov E, Izaurralde E, Igreja C. 4EHP and GIGYF1/2 Mediate Translation-Coupled Messenger RNA Decay. Cell Rep 2021; 33:108262. [PMID: 33053355 DOI: 10.1016/j.celrep.2020.108262] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 08/26/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Current models of mRNA turnover indicate that cytoplasmic degradation is coupled with translation. However, our understanding of the molecular events that coordinate ribosome transit with the mRNA decay machinery is still limited. Here, we show that 4EHP-GIGYF1/2 complexes trigger co-translational mRNA decay. Human cells lacking these proteins accumulate mRNAs with prominent ribosome pausing. They include, among others, transcripts encoding secretory and membrane-bound proteins or tubulin subunits. In addition, 4EHP-GIGYF1/2 complexes fail to reduce mRNA levels in the absence of ribosome stalling or upon disruption of their interaction with the cap structure, DDX6, and ZNF598. We further find that co-translational binding of GIGYF1/2 to the mRNA marks transcripts with perturbed elongation to decay. Our studies reveal how a repressor complex linked to neurological disorders minimizes the protein output of a subset of mRNAs.
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Affiliation(s)
- Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Min-Yi Chung
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Csilla Keskeny
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Ulrike Zinnall
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115 Berlin, Germany; IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115 Berlin, Germany; IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany.
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32
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Berger K, Pauwels E, Parkinson G, Landberg G, Le T, Demillo VG, Lumangtad LA, Jones DE, Islam MA, Olsen R, Kapri T, Intasiri A, Vermeire K, Rhost S, Bell TW. Reduction of Progranulin-Induced Breast Cancer Stem Cell Propagation by Sortilin-Targeting Cyclotriazadisulfonamide (CADA) Compounds. J Med Chem 2021; 64:12865-12876. [PMID: 34428050 PMCID: PMC10501753 DOI: 10.1021/acs.jmedchem.1c00943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclotriazadisulfonamide (CADA) compounds selectively down-modulate two human proteins of potential therapeutic interest, cluster of differentiation 4 (CD4) and sortilin. Progranulin is secreted from some breast cancer cells, causing dedifferentiation of receiving cancer cells and cancer stem cell proliferation. Inhibition of progranulin binding to sortilin, its main receptor, can block progranulin-induced metastatic breast cancer using a triple-negative in vivo xenograft model. In the current study, seven CADA compounds (CADA, VGD020, VGD071, TL020, TL023, LAL014, and DJ010) were examined for reduction of cellular sortilin expression and progranulin-induced breast cancer stem cell propagation. In addition, inhibition of progranulin-induced mammosphere formation was examined and found to be most significant for TL020, TL023, VGD071, and LAL014. Full experimental details are given for the synthesis and characterization of the four new compounds (TL020, TL023, VGD071, and DJ010). Comparison of solubilities, potencies, and cytotoxicities identified VGD071 as a promising candidate for future studies using mouse breast cancer models.
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Affiliation(s)
- Karoline Berger
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Eva Pauwels
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, 3000 Leuven, Belgium
| | - Gabrielle Parkinson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Göran Landberg
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Truc Le
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Violeta G Demillo
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Liezel A Lumangtad
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
- Nanosyn, 3100 Central Expressway, Santa Clara, California 95051, United States
| | - Dylan E Jones
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Md Azizul Islam
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Ryan Olsen
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Topprasad Kapri
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Amarawan Intasiri
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
| | - Kurt Vermeire
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, 3000 Leuven, Belgium
| | - Sara Rhost
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Thomas W Bell
- Department of Chemistry, University of Nevada, Reno, Nevada 89557-0216, United States
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33
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Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M. RNA Polymerase III Subunit Mutations in Genetic Diseases. Front Mol Biosci 2021; 8:696438. [PMID: 34395528 PMCID: PMC8362101 DOI: 10.3389/fmolb.2021.696438] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/21/2021] [Indexed: 12/24/2022] Open
Abstract
RNA polymerase (Pol) III transcribes small untranslated RNAs such as 5S ribosomal RNA, transfer RNAs, and U6 small nuclear RNA. Because of the functions of these RNAs, Pol III transcription is best known for its essential contribution to RNA maturation and translation. Surprisingly, it was discovered in the last decade that various inherited mutations in genes encoding nine distinct subunits of Pol III cause tissue-specific diseases rather than a general failure of all vital functions. Mutations in the POLR3A, POLR3C, POLR3E and POLR3F subunits are associated with susceptibility to varicella zoster virus-induced encephalitis and pneumonitis. In addition, an ever-increasing number of distinct mutations in the POLR3A, POLR3B, POLR1C and POLR3K subunits cause a spectrum of neurodegenerative diseases, which includes most notably hypomyelinating leukodystrophy. Furthermore, other rare diseases are also associated with mutations in genes encoding subunits of Pol III (POLR3H, POLR3GL) and the BRF1 component of the TFIIIB transcription initiation factor. Although the causal relationship between these mutations and disease development is widely accepted, the exact molecular mechanisms underlying disease pathogenesis remain enigmatic. Here, we review the current knowledge on the functional impact of specific mutations, possible Pol III-related disease-causing mechanisms, and animal models that may help to better understand the links between Pol III mutations and disease.
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Affiliation(s)
- Elisabeth Lata
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Karine Choquet
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Francis Sagliocco
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Martin Teichmann
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
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34
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Farkas Á, Bohnsack KE. Capture and delivery of tail-anchored proteins to the endoplasmic reticulum. J Cell Biol 2021; 220:212470. [PMID: 34264263 PMCID: PMC8287540 DOI: 10.1083/jcb.202105004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 11/22/2022] Open
Abstract
Tail-anchored (TA) proteins fulfill diverse cellular functions within different organellar membranes. Their characteristic C-terminal transmembrane segment renders TA proteins inherently prone to aggregation and necessitates their posttranslational targeting. The guided entry of TA proteins (GET in yeast)/transmembrane recognition complex (TRC in humans) pathway represents a major route for TA proteins to the endoplasmic reticulum (ER). Here, we review important new insights into the capture of nascent TA proteins at the ribosome by the GET pathway pretargeting complex and the mechanism of their delivery into the ER membrane by the GET receptor insertase. Interestingly, several alternative routes by which TA proteins can be targeted to the ER have emerged, raising intriguing questions about how selectivity is achieved during TA protein capture. Furthermore, mistargeting of TA proteins is a fundamental cellular problem, and we discuss the recently discovered quality control machineries in the ER and outer mitochondrial membrane for displacing mislocalized TA proteins.
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Affiliation(s)
- Ákos Farkas
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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35
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Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N. Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle. Cell Rep 2021; 36:109350. [PMID: 34260909 PMCID: PMC8330425 DOI: 10.1016/j.celrep.2021.109350] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/23/2021] [Accepted: 06/15/2021] [Indexed: 11/26/2022] Open
Abstract
Co-translational protein targeting to membranes by the signal recognition particle (SRP) is a universally conserved pathway from bacteria to humans. In mammals, SRP and its receptor (SR) have many additional RNA features and protein components compared to the bacterial system, which were recently shown to play regulatory roles. Due to its complexity, the mammalian SRP targeting process is mechanistically not well understood. In particular, it is not clear how SRP recognizes translating ribosomes with exposed signal sequences and how the GTPase activity of SRP and SR is regulated. Here, we present electron cryo-microscopy structures of SRP and SRP·SR in complex with the translating ribosome. The structures reveal the specific molecular interactions between SRP and the emerging signal sequence and the elements that regulate GTPase activity of SRP·SR. Our results suggest the molecular mechanism of how eukaryote-specific elements regulate the early and late stages of SRP-dependent protein targeting. Jomaa et al. present cryo-EM structures of mammalian SRP, SRP receptor, and the translating ribosome. The structures reveal the role of eukaryotic-specific features involved in regulating early and late stages of co-translational protein targeting to the endoplasmic reticulum and suggest a model for cargo recognition and handover.
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Affiliation(s)
- Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
| | - Simon Eitzinger
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Zikun Zhu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Kan Kobayashi
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
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36
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SRPassing Co-translational Targeting: The Role of the Signal Recognition Particle in Protein Targeting and mRNA Protection. Int J Mol Sci 2021; 22:ijms22126284. [PMID: 34208095 PMCID: PMC8230904 DOI: 10.3390/ijms22126284] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/02/2021] [Accepted: 06/05/2021] [Indexed: 01/13/2023] Open
Abstract
Signal recognition particle (SRP) is an RNA and protein complex that exists in all domains of life. It consists of one protein and one noncoding RNA in some bacteria. It is more complex in eukaryotes and consists of six proteins and one noncoding RNA in mammals. In the eukaryotic cytoplasm, SRP co-translationally targets proteins to the endoplasmic reticulum and prevents misfolding and aggregation of the secretory proteins in the cytoplasm. It was demonstrated recently that SRP also possesses an earlier unknown function, the protection of mRNAs of secretory proteins from degradation. In this review, we analyze the progress in studies of SRPs from different organisms, SRP biogenesis, its structure, and function in protein targeting and mRNA protection.
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37
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Soni K, Kempf G, Manalastas-Cantos K, Hendricks A, Flemming D, Guizetti J, Simon B, Frischknecht F, Svergun DI, Wild K, Sinning I. Structural analysis of the SRP Alu domain from Plasmodium falciparum reveals a non-canonical open conformation. Commun Biol 2021; 4:600. [PMID: 34017052 PMCID: PMC8137916 DOI: 10.1038/s42003-021-02132-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/22/2021] [Indexed: 12/25/2022] Open
Abstract
The eukaryotic signal recognition particle (SRP) contains an Alu domain, which docks into the factor binding site of translating ribosomes and confers translation retardation. The canonical Alu domain consists of the SRP9/14 protein heterodimer and a tRNA-like folded Alu RNA that adopts a strictly 'closed' conformation involving a loop-loop pseudoknot. Here, we study the structure of the Alu domain from Plasmodium falciparum (PfAlu), a divergent apicomplexan protozoan that causes human malaria. Using NMR, SAXS and cryo-EM analyses, we show that, in contrast to its prokaryotic and eukaryotic counterparts, the PfAlu domain adopts an 'open' Y-shaped conformation. We show that cytoplasmic P. falciparum ribosomes are non-discriminative and recognize both the open PfAlu and closed human Alu domains with nanomolar affinity. In contrast, human ribosomes do not provide high affinity binding sites for either of the Alu domains. Our analyses extend the structural database of Alu domains to the protozoan species and reveal species-specific differences in the recognition of SRP Alu domains by ribosomes.
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Affiliation(s)
- Komal Soni
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Georg Kempf
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Astrid Hendricks
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Dirk Flemming
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Julien Guizetti
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Bernd Simon
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany.
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38
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Lee JH, Jomaa A, Chung S, Hwang Fu YH, Qian R, Sun X, Hsieh HH, Chandrasekar S, Bi X, Mattei S, Boehringer D, Weiss S, Ban N, Shan SO. Receptor compaction and GTPase rearrangement drive SRP-mediated cotranslational protein translocation into the ER. SCIENCE ADVANCES 2021; 7:eabg0942. [PMID: 34020957 PMCID: PMC8139590 DOI: 10.1126/sciadv.abg0942] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/01/2021] [Indexed: 05/07/2023]
Abstract
The conserved signal recognition particle (SRP) cotranslationally delivers ~30% of the proteome to the eukaryotic endoplasmic reticulum (ER). The molecular mechanism by which eukaryotic SRP transitions from cargo recognition in the cytosol to protein translocation at the ER is not understood. Here, structural, biochemical, and single-molecule studies show that this transition requires multiple sequential conformational rearrangements in the targeting complex initiated by guanosine triphosphatase (GTPase)-driven compaction of the SRP receptor (SR). Disruption of these rearrangements, particularly in mutant SRP54G226E linked to severe congenital neutropenia, uncouples the SRP/SR GTPase cycle from protein translocation. Structures of targeting intermediates reveal the molecular basis of early SRP-SR recognition and emphasize the role of eukaryote-specific elements in regulating targeting. Our results provide a molecular model for the structural and functional transitions of SRP throughout the targeting cycle and show that these transitions provide important points for biological regulation that can be perturbed in genetic diseases.
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Affiliation(s)
- Jae Ho Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
| | - SangYoon Chung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yu-Hsien Hwang Fu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ruilin Qian
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Xuemeng Sun
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hao-Hsuan Hsieh
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Xiaotian Bi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Simone Mattei
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
- Cryo-EM Knowledge Hub, ETH Zurich, 8093 Zurich, Switzerland
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, 52900 Ramat-Gan, Israel
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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39
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Fernandes N, Buchan JR. RNAs as Regulators of Cellular Matchmaking. Front Mol Biosci 2021; 8:634146. [PMID: 33898516 PMCID: PMC8062979 DOI: 10.3389/fmolb.2021.634146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/22/2021] [Indexed: 12/30/2022] Open
Abstract
RNA molecules are increasingly being identified as facilitating or impeding the interaction of proteins and nucleic acids, serving as so-called scaffolds or decoys. Long non-coding RNAs have been commonly implicated in such roles, particularly in the regulation of nuclear processes including chromosome topology, regulation of chromatin state and gene transcription, and assembly of nuclear biomolecular condensates such as paraspeckles. Recently, an increased awareness of cytoplasmic RNA scaffolds and decoys has begun to emerge, including the identification of non-coding regions of mRNAs that can also function in a scaffold-like manner to regulate interactions of nascently translated proteins. Collectively, cytoplasmic RNA scaffolds and decoys are now implicated in processes such as mRNA translation, decay, protein localization, protein degradation and assembly of cytoplasmic biomolecular condensates such as P-bodies. Here, we review examples of RNA scaffolds and decoys in both the nucleus and cytoplasm, illustrating common themes, the suitability of RNA to such roles, and future challenges in identifying and better understanding RNA scaffolding and decoy functions.
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Affiliation(s)
| | - J. Ross Buchan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
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40
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Zhang Y, De Laurentiis E, Bohnsack KE, Wahlig M, Ranjan N, Gruseck S, Hackert P, Wölfle T, Rodnina MV, Schwappach B, Rospert S. Ribosome-bound Get4/5 facilitates the capture of tail-anchored proteins by Sgt2 in yeast. Nat Commun 2021; 12:782. [PMID: 33542241 PMCID: PMC7862611 DOI: 10.1038/s41467-021-20981-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/05/2021] [Indexed: 02/03/2023] Open
Abstract
The guided entry of tail-anchored proteins (GET) pathway assists in the posttranslational delivery of tail-anchored proteins, containing a single C-terminal transmembrane domain, to the ER. Here we uncover how the yeast GET pathway component Get4/5 facilitates capture of tail-anchored proteins by Sgt2, which interacts with tail-anchors and hands them over to the targeting component Get3. Get4/5 binds directly and with high affinity to ribosomes, positions Sgt2 close to the ribosomal tunnel exit, and facilitates the capture of tail-anchored proteins by Sgt2. The contact sites of Get4/5 on the ribosome overlap with those of SRP, the factor mediating cotranslational ER-targeting. Exposure of internal transmembrane domains at the tunnel exit induces high-affinity ribosome binding of SRP, which in turn prevents ribosome binding of Get4/5. In this way, the position of a transmembrane domain within nascent ER-targeted proteins mediates partitioning into either the GET or SRP pathway directly at the ribosomal tunnel exit. The guided entry of tail-anchored proteins (GET) pathway assists in the delivery of such proteins to the ER. Here, the authors reveal that the pathway components Get4/5 probe a region near the ribosomal exit tunnel. Upon emergence of a client protein, Get4/5 recruits Sgt2 and initiates the targeting phase of the pathway.
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Affiliation(s)
- Ying Zhang
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Evelina De Laurentiis
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Mascha Wahlig
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Namit Ranjan
- Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Simon Gruseck
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Philipp Hackert
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Tina Wölfle
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Marina V Rodnina
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany. .,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Göttingen, Germany.
| | - Sabine Rospert
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany. .,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany.
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41
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Rodríguez-Galán O, García-Gómez JJ, Rosado IV, Wei W, Méndez-Godoy A, Pillet B, Alekseenko A, Steinmetz L, Pelechano V, Kressler D, de la Cruz J. A functional connection between translation elongation and protein folding at the ribosome exit tunnel in Saccharomyces cerevisiae. Nucleic Acids Res 2021; 49:206-220. [PMID: 33330942 PMCID: PMC7797049 DOI: 10.1093/nar/gkaa1200] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/18/2020] [Accepted: 12/14/2020] [Indexed: 12/03/2022] Open
Abstract
Proteostasis needs to be tightly controlled to meet the cellular demand for correctly de novo folded proteins and to avoid protein aggregation. While a coupling between translation rate and co-translational folding, likely involving an interplay between the ribosome and its associated chaperones, clearly appears to exist, the underlying mechanisms and the contribution of ribosomal proteins remain to be explored. The ribosomal protein uL3 contains a long internal loop whose tip region is in close proximity to the ribosomal peptidyl transferase center. Intriguingly, the rpl3[W255C] allele, in which the residue making the closest contact to this catalytic site is mutated, affects diverse aspects of ribosome biogenesis and function. Here, we have uncovered, by performing a synthetic lethal screen with this allele, an unexpected link between translation and the folding of nascent proteins by the ribosome-associated Ssb-RAC chaperone system. Our results reveal that uL3 and Ssb-RAC cooperate to prevent 80S ribosomes from piling up within the 5' region of mRNAs early on during translation elongation. Together, our study provides compelling in vivo evidence for a functional connection between peptide bond formation at the peptidyl transferase center and chaperone-assisted de novo folding of nascent polypeptides at the solvent-side of the peptide exit tunnel.
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Affiliation(s)
- Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Juan J García-Gómez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Iván V Rosado
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Wu Wei
- Stanford Genome Technology Center, Stanford University, Palo Alto, CA, USA
- CAS Key Lab of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Alfonso Méndez-Godoy
- Unit of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Benjamin Pillet
- Unit of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Alisa Alekseenko
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna, Sweden
| | - Lars M Steinmetz
- Stanford Genome Technology Center, Stanford University, Palo Alto, CA, USA
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
- Department of Genetics, School of Medicine, Stanford, CA, USA
| | - Vicent Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna, Sweden
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
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42
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Lin KF, Fry MY, Saladi SM, Clemons WM. Molecular basis of tail-anchored integral membrane protein recognition by the cochaperone Sgt2. J Biol Chem 2021; 296:100441. [PMID: 33610544 PMCID: PMC8010706 DOI: 10.1016/j.jbc.2021.100441] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/04/2021] [Accepted: 02/17/2021] [Indexed: 02/08/2023] Open
Abstract
The targeting and insertion of tail-anchored (TA) integral membrane proteins (IMPs) into the correct membrane is critical for cellular homeostasis. The fungal protein Sgt2, and its human homolog SGTA, is the entry point for clients to the guided entry of tail-anchored protein (GET) pathway, which targets endoplasmic reticulum-bound TA IMPs. Consisting of three structurally independent domains, the C terminus of Sgt2 binds to the hydrophobic transmembrane domain (TMD) of clients. However, the exact binding interface within Sgt2 and molecular details that underlie its binding mechanism and client preference are not known. Here, we reveal the mechanism of Sgt2 binding to hydrophobic clients, including TA IMPs. Through sequence analysis, biophysical characterization, and a series of capture assays, we establish that the Sgt2 C-terminal domain is flexible but conserved and sufficient for client binding. A molecular model for this domain reveals a helical hand forming a hydrophobic groove approximately 15 Å long that is consistent with our observed higher affinity for client TMDs with a hydrophobic face and a minimal length of 11 residues. This work places Sgt2 into a broader family of TPR-containing cochaperone proteins, demonstrating structural and sequence-based similarities to the DP domains in the yeast Hsp90 and Hsp70 coordinating protein, Sti1.
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Affiliation(s)
- Ku-Feng Lin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Michelle Y Fry
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Shyam M Saladi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - William M Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA.
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43
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A ribosome-associated chaperone enables substrate triage in a cotranslational protein targeting complex. Nat Commun 2020; 11:5840. [PMID: 33203865 PMCID: PMC7673040 DOI: 10.1038/s41467-020-19548-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/20/2020] [Indexed: 12/22/2022] Open
Abstract
Protein biogenesis is essential in all cells and initiates when a nascent polypeptide emerges from the ribosome exit tunnel, where multiple ribosome-associated protein biogenesis factors (RPBs) direct nascent proteins to distinct fates. How distinct RPBs spatiotemporally coordinate with one another to affect accurate protein biogenesis is an emerging question. Here, we address this question by studying the role of a cotranslational chaperone, nascent polypeptide-associated complex (NAC), in regulating substrate selection by signal recognition particle (SRP), a universally conserved protein targeting machine. We show that mammalian SRP and SRP receptors (SR) are insufficient to generate the biologically required specificity for protein targeting to the endoplasmic reticulum. NAC co-binds with and remodels the conformational landscape of SRP on the ribosome to regulate its interaction kinetics with SR, thereby reducing the nonspecific targeting of signalless ribosomes and pre-emptive targeting of ribosomes with short nascent chains. Mathematical modeling demonstrates that the NAC-induced regulations of SRP activity are essential for the fidelity of cotranslational protein targeting. Our work establishes a molecular model for how NAC acts as a triage factor to prevent protein mislocalization, and demonstrates how the macromolecular crowding of RPBs at the ribosome exit site enhances the fidelity of substrate selection into individual protein biogenesis pathways.
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44
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Syntheses and anti-HIV and human cluster of differentiation 4 (CD4) down-modulating potencies of pyridine-fused cyclotriazadisulfonamide (CADA) compounds. Bioorg Med Chem 2020; 28:115816. [PMID: 33181479 DOI: 10.1016/j.bmc.2020.115816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 01/10/2023]
Abstract
CADA compounds selectively down-modulate human cell-surface CD4 protein and are of interest as HIV entry inhibitors and as drugs for asthma, rheumatoid arthritis, diabetes and some cancers. Postulating that fusing a pyridine ring bearing hydrophobic substituents into the macrocyclic scaffold of CADA compounds may lead to potent compounds with improved properties, 17 macrocycles were synthesized, 14 with 12-membered rings having an isobutylene head group, two arenesulfonyl side arms, and fused pyridine rings bearing a para substituent. The analogs display a wide range of CD4 down-modulating and anti-HIV potencies, including some with greater potency than CADA, proving that a highly basic nitrogen atom in the 12-membered ring is not required for potency and that hydrophobic substituents enhance potency of pyridine-fused CADA compounds. Cytotoxicities of the new compounds compared favorably with those of CADA, showing that incorporation of a pyridine ring into the macrocyclic scaffold can produce selective compounds for potently down-modulating proteins of medicinal interest.
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45
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Banerjee AK, Blanco MR, Bruce EA, Honson DD, Chen LM, Chow A, Bhat P, Ollikainen N, Quinodoz SA, Loney C, Thai J, Miller ZD, Lin AE, Schmidt MM, Stewart DG, Goldfarb D, De Lorenzo G, Rihn SJ, Voorhees RM, Botten JW, Majumdar D, Guttman M. SARS-CoV-2 Disrupts Splicing, Translation, and Protein Trafficking to Suppress Host Defenses. Cell 2020; 183:1325-1339.e21. [PMID: 33080218 PMCID: PMC7543886 DOI: 10.1016/j.cell.2020.10.004] [Citation(s) in RCA: 365] [Impact Index Per Article: 91.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/26/2020] [Accepted: 10/02/2020] [Indexed: 12/26/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently identified coronavirus that causes the respiratory disease known as coronavirus disease 2019 (COVID-19). Despite the urgent need, we still do not fully understand the molecular basis of SARS-CoV-2 pathogenesis. Here, we comprehensively define the interactions between SARS-CoV-2 proteins and human RNAs. NSP16 binds to the mRNA recognition domains of the U1 and U2 splicing RNAs and acts to suppress global mRNA splicing upon SARS-CoV-2 infection. NSP1 binds to 18S ribosomal RNA in the mRNA entry channel of the ribosome and leads to global inhibition of mRNA translation upon infection. Finally, NSP8 and NSP9 bind to the 7SL RNA in the signal recognition particle and interfere with protein trafficking to the cell membrane upon infection. Disruption of each of these essential cellular functions acts to suppress the interferon response to viral infection. Our results uncover a multipronged strategy utilized by SARS-CoV-2 to antagonize essential cellular processes to suppress host defenses. NSP16 binds mRNA recognition domains of U1/U2 snRNAs and disrupts mRNA splicing NSP1 binds in the mRNA entry channel of the ribosome to disrupt protein translation NSP8 and NSP9 bind the signal recognition particle and disrupt protein trafficking These disruptions of protein production suppress the interferon response to infection
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Affiliation(s)
- Abhik K Banerjee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Mario R Blanco
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Emily A Bruce
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Drew D Honson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Linlin M Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Amy Chow
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Prashant Bhat
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Noah Ollikainen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sofia A Quinodoz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Colin Loney
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Jasmine Thai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Zachary D Miller
- Department of Surgery and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Aaron E Lin
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Madaline M Schmidt
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Douglas G Stewart
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Daniel Goldfarb
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Giuditta De Lorenzo
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Suzannah J Rihn
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jason W Botten
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Devdoot Majumdar
- Department of Surgery and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA.
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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46
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Azar P, Mejía JE, Cenac C, Shaiykova A, Youness A, Laffont S, Essat A, Izopet J, Passaes C, Müller-Trutwin M, Delobel P, Meyer L, Guéry JC. TLR7 dosage polymorphism shapes interferogenesis and HIV-1 acute viremia in women. JCI Insight 2020; 5:136047. [PMID: 32554924 DOI: 10.1172/jci.insight.136047] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/06/2020] [Indexed: 12/25/2022] Open
Abstract
Type I IFN (IFN-I) production by plasmacytoid DCs (pDCs) occurs during acute HIV-1 infection in response to TLR7 stimulation, but the role of pDC-derived IFN-I in controlling or promoting HIV-1 infection is ambiguous. We report here a sex-biased interferogenic phenotype for a frequent single-nucleotide polymorphism of human TLR7, rs179008, displaying an impact on key parameters of acute HIV-1 infection. We show allele rs179008 T to determine lower TLR7 protein abundance in cells from women, specifically - likely by diminishing TLR7 mRNA translation efficiency through codon usage. The hypomorphic TLR7 phenotype is mirrored by decreased TLR7-driven IFN-I production by female pDCs. Among women from the French ANRS PRIMO cohort of acute HIV-1 patients, carriage of allele rs179008 T associated with lower viremia, cell-associated HIV-1 DNA, and CXCL10 (IP-10) plasma concentrations. RNA viral load was decreased by 0.85 log10 (95% CI, -1.51 to -0.18) among T/T homozygotes, who also exhibited a lower frequency of acute symptoms. TLR7 emerges as an important control locus for acute HIV-1 viremia, and the clinical phenotype for allele rs179008 T, carried by 30%-50% of European women, supports a beneficial effect of toning down TLR7-driven IFN-I production by pDCs during acute HIV-1 infection.
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Affiliation(s)
- Pascal Azar
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
| | - José Enrique Mejía
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
| | - Claire Cenac
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
| | - Arnoo Shaiykova
- Centre de Recherche en Epidémiologie et Santé des Populations (CESP), Université Paris-Sud, Université Paris-Saclay, INSERM, Le Kremlin-Bicêtre, France
| | - Ali Youness
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
| | - Sophie Laffont
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
| | - Asma Essat
- Centre de Recherche en Epidémiologie et Santé des Populations (CESP), Université Paris-Sud, Université Paris-Saclay, INSERM, Le Kremlin-Bicêtre, France
| | - Jacques Izopet
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France.,Laboratoire de Virologie, CHU Purpan, Toulouse, France
| | - Caroline Passaes
- Institut Pasteur, Unité HIV Inflammation et Persistance, Paris, France
| | | | - Pierre Delobel
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France.,Service des Maladies Infectieuses et Tropicales, CHU Purpan, Toulouse, France
| | - Laurence Meyer
- Centre de Recherche en Epidémiologie et Santé des Populations (CESP), Université Paris-Sud, Université Paris-Saclay, INSERM, Le Kremlin-Bicêtre, France
| | - Jean-Charles Guéry
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UMR 1043 INSERM, CNRS, Toulouse, France
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47
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O'Donnell JP, Phillips BP, Yagita Y, Juszkiewicz S, Wagner A, Malinverni D, Keenan RJ, Miller EA, Hegde RS. The architecture of EMC reveals a path for membrane protein insertion. eLife 2020; 9:e57887. [PMID: 32459176 PMCID: PMC7292650 DOI: 10.7554/elife.57887] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/26/2020] [Indexed: 12/29/2022] Open
Abstract
Approximately 25% of eukaryotic genes code for integral membrane proteins that are assembled at the endoplasmic reticulum. An abundant and widely conserved multi-protein complex termed EMC has been implicated in membrane protein biogenesis, but its mechanism of action is poorly understood. Here, we define the composition and architecture of human EMC using biochemical assays, crystallography of individual subunits, site-specific photocrosslinking, and cryo-EM reconstruction. Our results suggest that EMC's cytosolic domain contains a large, moderately hydrophobic vestibule that can bind a substrate's transmembrane domain (TMD). The cytosolic vestibule leads into a lumenally-sealed, lipid-exposed intramembrane groove large enough to accommodate a single substrate TMD. A gap between the cytosolic vestibule and intramembrane groove provides a potential path for substrate egress from EMC. These findings suggest how EMC facilitates energy-independent membrane insertion of TMDs, explain why only short lumenal domains are translocated by EMC, and constrain models of EMC's proposed chaperone function.
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Affiliation(s)
| | - Ben P Phillips
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Yuichi Yagita
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | | | | | - Robert J Keenan
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
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48
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Lumangtad LA, Bell TW. The signal peptide as a new target for drug design. Bioorg Med Chem Lett 2020; 30:127115. [PMID: 32209293 PMCID: PMC7138182 DOI: 10.1016/j.bmcl.2020.127115] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/06/2020] [Accepted: 03/15/2020] [Indexed: 01/16/2023]
Abstract
Many current and potential drug targets are membrane-bound or secreted proteins that are expressed and transported via the Sec61 secretory pathway. They are targeted to translocon channels across the membrane of the endoplasmic reticulum (ER) by signal peptides (SPs), which are temporary structures on the N-termini of their nascent chains. During translation, such proteins enter the lumen and membrane of the ER by a process known as co-translational translocation. Small molecules have been found that interfere with this process, decreasing protein expression by recognizing the unique structures of the SPs of particular proteins. The SP may thus become a validated target for designing drugs for numerous disorders, including certain hereditary diseases.
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Affiliation(s)
| | - Thomas W Bell
- Department of Chemistry, University of Nevada, Reno, NV 89557-0216, USA.
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49
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Phillips BP, Gomez-Navarro N, Miller EA. Protein quality control in the endoplasmic reticulum. Curr Opin Cell Biol 2020; 65:96-102. [PMID: 32408120 PMCID: PMC7588826 DOI: 10.1016/j.ceb.2020.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/02/2020] [Accepted: 04/02/2020] [Indexed: 11/30/2022]
Abstract
Misfolded and mistargeted proteins in the early secretory pathway present significant risks to the cell. A diverse and integrated network of quality control pathways protects the cell from these threats. We focus on the discovery of new mechanisms that contribute to this protective network. Biochemical and structural advances in endoplasmic reticulum targeting fidelity, and in the redistribution of mistargeted substrates are discussed. We further review new discoveries in quality control at the inner nuclear membrane in the context of orphaned subunits. We consider developments in our understanding of cargo selection for endoplasmic reticulum export. Conflicting data on quality control by cargo receptor proteins are discussed and we look to important future questions for the field.
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50
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Carter SD, Hampton CM, Langlois R, Melero R, Farino ZJ, Calderon MJ, Li W, Wallace CT, Tran NH, Grassucci RA, Siegmund SE, Pemberton J, Morgenstern TJ, Eisenman L, Aguilar JI, Greenberg NL, Levy ES, Yi E, Mitchell WG, Rice WJ, Wigge C, Pilli J, George EW, Aslanoglou D, Courel M, Freyberg RJ, Javitch JA, Wills ZP, Area-Gomez E, Shiva S, Bartolini F, Volchuk A, Murray SA, Aridor M, Fish KN, Walter P, Balla T, Fass D, Wolf SG, Watkins SC, Carazo JM, Jensen GJ, Frank J, Freyberg Z. Ribosome-associated vesicles: A dynamic subcompartment of the endoplasmic reticulum in secretory cells. SCIENCE ADVANCES 2020; 6:eaay9572. [PMID: 32270040 PMCID: PMC7112762 DOI: 10.1126/sciadv.aay9572] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/13/2020] [Indexed: 05/21/2023]
Abstract
The endoplasmic reticulum (ER) is a highly dynamic network of membranes. Here, we combine live-cell microscopy with in situ cryo-electron tomography to directly visualize ER dynamics in several secretory cell types including pancreatic β-cells and neurons under near-native conditions. Using these imaging approaches, we identify a novel, mobile form of ER, ribosome-associated vesicles (RAVs), found primarily in the cell periphery, which is conserved across different cell types and species. We show that RAVs exist as distinct, highly dynamic structures separate from the intact ER reticular architecture that interact with mitochondria via direct intermembrane contacts. These findings describe a new ER subcompartment within cells.
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Affiliation(s)
- Stephen D. Carter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Cheri M. Hampton
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Robert Langlois
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Roberto Melero
- Biocomputing Unit, Centro Nacional de Biotecnología–CSIC, Darwin 3, Campus Universidad Autónoma, 28049 Madrid, Spain
| | - Zachary J. Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Michael J. Calderon
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Wen Li
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Callen T. Wallace
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Ngoc Han Tran
- HHMI, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Robert A. Grassucci
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Stephanie E. Siegmund
- Department of Cellular, Molecular and Biophysical Studies, Columbia University Medical Center, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Travis J. Morgenstern
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Leanna Eisenman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jenny I. Aguilar
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Nili L. Greenberg
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Elana S. Levy
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Edward Yi
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - William G. Mitchell
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | | | | | - Jyotsna Pilli
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Emily W. George
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Despoina Aslanoglou
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Maïté Courel
- CNRS-UMR7622, Institut de Biologie Paris-Seine, Université Pierre & Marie Curie, 75252 Paris, France
| | - Robin J. Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jonathan A. Javitch
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Zachary P. Wills
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Estela Area-Gomez
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Francesca Bartolini
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Allen Volchuk
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sandra A. Murray
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Meir Aridor
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Kenneth N. Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Peter Walter
- HHMI, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Deborah Fass
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Sharon G. Wolf
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Simon C. Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - José María Carazo
- Biocomputing Unit, Centro Nacional de Biotecnología–CSIC, Darwin 3, Campus Universidad Autónoma, 28049 Madrid, Spain
| | - Grant J. Jensen
- HHMI, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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