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Saha S, Gonzalez-Maeso J. Translation-independent association of mRNAs encoding protomers of the 5-HT 2A -mGlu2 receptor complex in living cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.599432. [PMID: 38948858 PMCID: PMC11212926 DOI: 10.1101/2024.06.17.599432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The serotonin 2A receptor (5-HT 2A R) and the metabotropic glutamate 2 receptor (mGluR2) form heteromeric G protein-coupled receptor (GPCR) complexes through a direct physical interaction. Co-translational association of mRNAs encoding subunits of heteromeric ion channels has been reported, but whether complex assembly of GPCRs occurs during translation remains unknown. Our in vitro data reveal evidence of co-translational modulation in 5-HT 2A R and mGluR2 mRNAs following siRNA-mediated knockdown. Interestingly, immunoprecipitation of either 5-HT 2A R or mGluR2, using an antibody targeting epitope tags at their N-terminus, results in detection of both transcripts associated with ribonucleoprotein complexes containing RPS24. Additionally, we demonstrate that the mRNA transcripts of 5-HT 2A R and mGluR2 associate autonomously of their respective encoded proteins. Validation of this translation-independent association is extended ex vivo using mouse frontal cortex samples. Together, these findings provide mechanistic insights into the co-translational assembly of GPCR heteromeric complexes, unraveling regulatory processes governing protein-protein interactions and complex formation.
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2
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Yoon J, Zhang YM, Her C, Grant RA, Ponomarenko AI, Ackermann BE, Hui T, Lin YS, Debelouchina GT, Shoulders MD. The immune-evasive proline-283 substitution in influenza nucleoprotein increases aggregation propensity without altering the native structure. SCIENCE ADVANCES 2024; 10:eadl6144. [PMID: 38640233 PMCID: PMC11029814 DOI: 10.1126/sciadv.adl6144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/15/2024] [Indexed: 04/21/2024]
Abstract
Nucleoprotein (NP) is a key structural protein of influenza ribonucleoprotein complexes and is central to viral RNA packing and trafficking. NP also determines the sensitivity of influenza to myxovirus resistance protein 1 (MxA), an innate immunity factor that restricts influenza replication. A few critical MxA-resistant mutations have been identified in NP, including the highly conserved proline-283 substitution. This essential proline-283 substitution impairs influenza growth, a fitness defect that becomes particularly prominent at febrile temperature (39°C) when host chaperones are depleted. Here, we biophysically characterize proline-283 NP and serine-283 NP to test whether the fitness defect is caused by the proline-283 substitution introducing folding defects. We show that the proline-283 substitution changes the folding pathway of NP, making NP more aggregation prone during folding, but does not alter the native structure of the protein. These findings suggest that influenza has evolved to hijack host chaperones to promote the folding of otherwise biophysically incompetent viral proteins that enable innate immune system escape.
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Affiliation(s)
- Jimin Yoon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yu Meng Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Cheenou Her
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Robert A. Grant
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Anna I. Ponomarenko
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bryce E. Ackermann
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Tiffani Hui
- Department of Chemistry, Tufts University, Medford, MA, USA
| | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, MA, USA
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Matthew D. Shoulders
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
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3
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Venezian J, Bar-Yosef H, Ben-Arie Zilberman H, Cohen N, Kleifeld O, Fernandez-Recio J, Glaser F, Shiber A. Diverging co-translational protein complex assembly pathways are governed by interface energy distribution. Nat Commun 2024; 15:2638. [PMID: 38528060 DOI: 10.1038/s41467-024-46881-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: 10/09/2023] [Accepted: 03/12/2024] [Indexed: 03/27/2024] Open
Abstract
Protein-protein interactions are at the heart of all cellular processes, with the ribosome emerging as a platform, orchestrating the nascent-chain interplay dynamics. Here, to study the characteristics governing co-translational protein folding and complex assembly, we combine selective ribosome profiling, imaging, and N-terminomics with all-atoms molecular dynamics. Focusing on conserved N-terminal acetyltransferases (NATs), we uncover diverging co-translational assembly pathways, where highly homologous subunits serve opposite functions. We find that only a few residues serve as "hotspots," initiating co-translational assembly interactions upon exposure at the ribosome exit tunnel. These hotspots are characterized by high binding energy, anchoring the entire interface assembly. Alpha-helices harboring hotspots are highly thermolabile, folding and unfolding during simulations, depending on their partner subunit to avoid misfolding. In vivo hotspot mutations disrupted co-translational complexation, leading to aggregation. Accordingly, conservation analysis reveals that missense NATs variants, causing neurodevelopmental and neurodegenerative diseases, disrupt putative hotspot clusters. Expanding our study to include phosphofructokinase, anthranilate synthase, and nucleoporin subcomplex, we employ AlphaFold-Multimer to model the complexes' complete structures. Computing MD-derived interface energy profiles, we find similar trends. Here, we propose a model based on the distribution of interface energy as a strong predictor of co-translational assembly.
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Affiliation(s)
- Johannes Venezian
- Faculty of Biology, Technion Israel institute of Technology, Haifa, Israel
| | - Hagit Bar-Yosef
- Faculty of Biology, Technion Israel institute of Technology, Haifa, Israel
| | | | - Noam Cohen
- Faculty of Biology, Technion Israel institute of Technology, Haifa, Israel
| | - Oded Kleifeld
- Faculty of Biology, Technion Israel institute of Technology, Haifa, Israel
| | - Juan Fernandez-Recio
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC-Universidad de La Rioja-Gobierno de La Rioja, Logroño, Spain
| | - Fabian Glaser
- Lorry I. Lokey Interdisciplinary Center for Life Sciences & Engineering, Haifa, Israel
| | - Ayala Shiber
- Faculty of Biology, Technion Israel institute of Technology, Haifa, Israel.
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4
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Lewis BM, Cho CY, Her HL, Mizrahi O, Hunter T, Yeo GW. LARP4 is an RNA-binding protein that binds nuclear-encoded mitochondrial mRNAs to promote mitochondrial function. RNA (NEW YORK, N.Y.) 2024; 30:223-239. [PMID: 38164626 PMCID: PMC10870378 DOI: 10.1261/rna.079799.123] [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: 08/11/2023] [Accepted: 11/25/2023] [Indexed: 01/03/2024]
Abstract
Mitochondria-associated RNA-binding proteins (RBPs) have emerged as key contributors to mitochondrial biogenesis and homeostasis. With few examples known, we set out to identify RBPs that regulate nuclear-encoded mitochondrial mRNAs (NEMmRNAs). Our systematic analysis of RNA targets of 150 RBPs identified RBPs with a preference for binding NEMmRNAs, including LARP4, a La RBP family member. We show that LARP4's targets are particularly enriched in mRNAs that encode respiratory chain complex proteins (RCCPs) and mitochondrial ribosome proteins (MRPs) across multiple human cell lines. Through quantitative proteomics, we demonstrate that depletion of LARP4 leads to a significant reduction in RCCP and MRP protein levels. Furthermore, we show that LARP4 depletion reduces mitochondrial function, and that LARP4 re-expression rescues this phenotype. Our findings shed light on a novel function for LARP4 as an RBP that binds to and positively regulates NEMmRNAs to promote mitochondrial respiratory function.
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Affiliation(s)
- Benjamin M Lewis
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92037, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92037, USA
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Chae Yun Cho
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Hsuan-Lin Her
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92037, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92037, USA
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, California 92037, USA
| | - Orel Mizrahi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92037, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92037, USA
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92037, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92037, USA
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5
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Bernardini A, Tora L. Co-translational Assembly Pathways of Nuclear Multiprotein Complexes Involved in the Regulation of Gene Transcription. J Mol Biol 2024; 436:168382. [PMID: 38061625 DOI: 10.1016/j.jmb.2023.168382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/24/2023] [Accepted: 12/01/2023] [Indexed: 12/18/2023]
Abstract
Most factors that regulate gene transcription in eukaryotic cells are multimeric, often large, protein complexes. The understanding of the biogenesis pathways of such large and heterogeneous protein assemblies, as well as the dimerization partner choice among transcription factors, is crucial to interpret and control gene expression programs and consequent cell fate decisions. Co-translational assembly (Co-TA) is thought to play key roles in the biogenesis of protein complexes by directing complex formation during protein synthesis. In this review we discuss the principles of Co-TA with a special focus for the assembly of transcription regulatory complexes. We outline the expected molecular advantages of establishing co-translational interactions, pointing at the available, or missing, evidence for each of them. We hypothesize different molecular mechanisms based on Co-TA to explain the allocation "dilemma" of paralog proteins and subunits shared by different transcription complexes. By taking as a paradigm the different assembly pathways employed by three related transcription regulatory complexes (TFIID, SAGA and ATAC), we discuss alternative Co-TA strategies for nuclear multiprotein complexes and the widespread - yet specific - use of Co-TA for the formation of nuclear complexes involved in gene transcription. Ultimately, we outlined a series of open questions which demand well-defined lines of research to investigate the principles of gene regulation that rely on the coordinated assembly of protein complexes.
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Affiliation(s)
- Andrea Bernardini
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964 Illkirch, France; Université de Strasbourg, Illkirch, France.
| | - László Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964 Illkirch, France; Université de Strasbourg, Illkirch, France.
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6
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Blake LA, De La Cruz A, Wu B. Imaging spatiotemporal translation regulation in vivo. Semin Cell Dev Biol 2024; 154:155-164. [PMID: 36963991 PMCID: PMC10514244 DOI: 10.1016/j.semcdb.2023.03.006] [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: 03/23/2022] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023]
Abstract
Translation is regulated spatiotemporally to direct protein synthesis when and where it is needed. RNA localization and local translation have been observed in various subcellular compartments, allowing cells to rapidly and finely adjust their proteome post-transcriptionally. Local translation on membrane-bound organelles is important to efficiently synthesize proteins targeted to the organelles. Protein-RNA phase condensates restrict RNA spatially in membraneless organelles and play essential roles in translation regulation and RNA metabolism. In addition, the temporal translation kinetics not only determine the amount of protein produced, but also serve as an important checkpoint for the quality of ribosomes, mRNAs, and nascent proteins. Translation imaging provides a unique capability to study these fundamental processes in the native environment. Recent breakthroughs in imaging enabled real-time visualization of translation of single mRNAs, making it possible to determine the spatial distribution and key biochemical parameters of in vivo translation dynamics. Here we reviewed the recent advances in translation imaging methods and their applications to study spatiotemporal translation regulation in vivo.
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Affiliation(s)
- Lauren A Blake
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ana De La Cruz
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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7
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Beck M, Covino R, Hänelt I, Müller-McNicoll M. Understanding the cell: Future views of structural biology. Cell 2024; 187:545-562. [PMID: 38306981 DOI: 10.1016/j.cell.2023.12.017] [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: 10/04/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 02/04/2024]
Abstract
Determining the structure and mechanisms of all individual functional modules of cells at high molecular detail has often been seen as equal to understanding how cells work. Recent technical advances have led to a flush of high-resolution structures of various macromolecular machines, but despite this wealth of detailed information, our understanding of cellular function remains incomplete. Here, we discuss present-day limitations of structural biology and highlight novel technologies that may enable us to analyze molecular functions directly inside cells. We predict that the progression toward structural cell biology will involve a shift toward conceptualizing a 4D virtual reality of cells using digital twins. These will capture cellular segments in a highly enriched molecular detail, include dynamic changes, and facilitate simulations of molecular processes, leading to novel and experimentally testable predictions. Transferring biological questions into algorithms that learn from the existing wealth of data and explore novel solutions may ultimately unveil how cells work.
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Affiliation(s)
- Martin Beck
- Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany; Goethe University Frankfurt, Frankfurt, Germany.
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
| | - Inga Hänelt
- Goethe University Frankfurt, Frankfurt, Germany.
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8
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Kong KYE, Shankar S, Rühle F, Khmelinskii A. Orphan quality control by an SCF ubiquitin ligase directed to pervasive C-degrons. Nat Commun 2023; 14:8363. [PMID: 38102142 PMCID: PMC10724198 DOI: 10.1038/s41467-023-44096-z] [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: 08/11/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Selective protein degradation typically involves substrate recognition via short linear motifs known as degrons. Various degrons can be found at protein termini from bacteria to mammals. While N-degrons have been extensively studied, our understanding of C-degrons is still limited. Towards a comprehensive understanding of eukaryotic C-degron pathways, here we perform an unbiased survey of C-degrons in budding yeast. We identify over 5000 potential C-degrons by stability profiling of random peptide libraries and of the yeast C‑terminome. Combining machine learning, high-throughput mutagenesis and genetic screens reveals that the SCF ubiquitin ligase targets ~40% of degrons using a single F-box substrate receptor Das1. Although sequence-specific, Das1 is highly promiscuous, recognizing a variety of C-degron motifs. By screening for full-length substrates, we implicate SCFDas1 in degradation of orphan protein complex subunits. Altogether, this work highlights the variety of C-degron pathways in eukaryotes and uncovers how an SCF/C-degron pathway of broad specificity contributes to proteostasis.
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Affiliation(s)
| | | | - Frank Rühle
- Institute of Molecular Biology (IMB), Mainz, Germany
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9
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Penzo A, Palancade B. Puzzling out nuclear pore complex assembly. FEBS Lett 2023; 597:2705-2727. [PMID: 37548888 DOI: 10.1002/1873-3468.14713] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 08/08/2023]
Abstract
Nuclear pore complexes (NPCs) are sophisticated multiprotein assemblies embedded within the nuclear envelope and controlling the exchanges of molecules between the cytoplasm and the nucleus. In this review, we summarize the mechanisms by which these elaborate complexes are built from their subunits, the nucleoporins, based on our ever-growing knowledge of NPC structural organization and on the recent identification of additional features of this process. We present the constraints faced during the production of nucleoporins, their gathering into oligomeric complexes, and the formation of NPCs within nuclear envelopes, and review the cellular strategies at play, from co-translational assembly to the enrolment of a panel of cofactors. Remarkably, the study of NPCs can inform our perception of the biogenesis of multiprotein complexes in general - and vice versa.
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Affiliation(s)
- Arianna Penzo
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Benoit Palancade
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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10
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Yayli G, Bernardini A, Mendoza Sanchez PK, Scheer E, Damilot M, Essabri K, Morlet B, Negroni L, Vincent SD, Timmers HTM, Tora L. ATAC and SAGA co-activator complexes utilize co-translational assembly, but their cellular localization properties and functions are distinct. Cell Rep 2023; 42:113099. [PMID: 37682711 PMCID: PMC10591836 DOI: 10.1016/j.celrep.2023.113099] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 06/19/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
To understand the function of multisubunit complexes, it is of key importance to uncover the precise mechanisms that guide their assembly. Nascent proteins can find and bind their interaction partners during their translation, leading to co-translational assembly. Here, we demonstrate that the core modules of ATAC (ADA-two-A-containing) and SAGA (Spt-Ada-Gcn5-acetyltransferase), two lysine acetyl transferase-containing transcription co-activator complexes, assemble co-translationally in the cytoplasm of mammalian cells. In addition, a SAGA complex containing all of its modules forms in the cytoplasm and acetylates non-histone proteins. In contrast, ATAC complex subunits cannot be detected in the cytoplasm of mammalian cells. However, an endogenous ATAC complex containing two functional modules forms and functions in the nucleus. Thus, the two related co-activators, ATAC and SAGA, assemble using co-translational pathways, but their subcellular localization, cytoplasmic abundance, and functions are distinct.
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Affiliation(s)
- Gizem Yayli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Andrea Bernardini
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Paulina Karen Mendoza Sanchez
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Freiburg, Germany; Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Elisabeth Scheer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Mylène Damilot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Karim Essabri
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Luc Negroni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Stéphane D Vincent
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - H T Marc Timmers
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Freiburg, Germany; Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - László Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France.
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11
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Yoon J, Zhang YM, Her C, Grant RA, Ponomarenko AM, Ackermann BE, Debelouchina GT, Shoulders MD. The Immune-Evasive Proline 283 Substitution in Influenza Nucleoprotein Increases Aggregation Propensity Without Altering the Native Structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.08.556894. [PMID: 37745335 PMCID: PMC10515774 DOI: 10.1101/2023.09.08.556894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Nucleoprotein (NP) is a key structural protein of influenza ribonucleoprotein complexes and is central to viral RNA packing and trafficking. In human cells, the interferon induced Myxovirus resistance protein 1 (MxA) binds to NP and restricts influenza replication. This selection pressure has caused NP to evolve a few critical MxA-resistant mutations, particularly the highly conserved Pro283 substitution. Previous work showed that this essential Pro283 substitution impairs influenza growth, and the fitness defect becomes particularly prominent at febrile temperature (39 °C) when host chaperones are depleted. Here, we biophysically characterize Pro283 NP and Ser283 NP to test if the fitness defect is owing to Pro283 substitution introducing folding defects. We show that the Pro283 substitution changes the folding pathway of NP without altering the native structure, making NP more aggregation prone during folding. These findings suggest that influenza has evolved to hijack host chaperones to promote the folding of otherwise biophysically incompetent viral proteins that enable innate immune system escape. Teaser Pro283 substitution in flu nucleoprotein introduces folding defects, and makes influenza uniquely dependent on host chaperones.
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12
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Höpfler M, Hegde RS. Control of mRNA fate by its encoded nascent polypeptide. Mol Cell 2023; 83:2840-2855. [PMID: 37595554 PMCID: PMC10501990 DOI: 10.1016/j.molcel.2023.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/03/2023] [Accepted: 07/11/2023] [Indexed: 08/20/2023]
Abstract
Cells tightly regulate mRNA processing, localization, and stability to ensure accurate gene expression in diverse cellular states and conditions. Most of these regulatory steps have traditionally been thought to occur before translation by the action of RNA-binding proteins. Several recent discoveries highlight multiple co-translational mechanisms that modulate mRNA translation, localization, processing, and stability. These mechanisms operate by recognition of the nascent protein, which is necessarily coupled to its encoding mRNA during translation. Hence, the distinctive sequence or structure of a particular nascent chain can recruit recognition factors with privileged access to the corresponding mRNA in an otherwise crowded cellular environment. Here, we draw on both well-established and recent examples to provide a conceptual framework for how cells exploit nascent protein recognition to direct mRNA fate. These mechanisms allow cells to dynamically and specifically regulate their transcriptomes in response to changes in cellular states to maintain protein homeostasis.
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13
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Yayli G, Bernardini A, Sanchez PKM, Scheer E, Damilot M, Essabri K, Morlet B, Negroni L, Vincent SD, Timmers HTM, Tora L. ATAC and SAGA coactivator complexes utilize co-translational assembly, but their cellular localization properties and functions are distinct. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.03.551787. [PMID: 37577620 PMCID: PMC10418265 DOI: 10.1101/2023.08.03.551787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
To understand the function of multisubunit complexes it is of key importance to uncover the precise mechanisms that guide their assembly. Nascent proteins can find and bind their interaction partners during their translation, leading to co-translational assembly. Here we demonstrate that the core modules of ATAC (ADA-Two-A-Containing) and SAGA (Spt-Ada-Gcn5-acetyltransferase), two lysine acetyl transferase-containing transcription coactivator complexes, assemble co-translationally in the cytoplasm of mammalian cells. In addition, SAGA complex containing all of its modules forms in the cytoplasm and acetylates non-histones proteins. In contrast, fully assembled ATAC complex cannot be detected in the cytoplasm of mammalian cells. However, endogenous ATAC complex containing two functional modules forms and functions in the nucleus. Thus, the two related coactivators, ATAC and SAGA, assemble by using co-translational pathways, but their subcellular localization, cytoplasmic abundance and functions are distinct.
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Affiliation(s)
- Gizem Yayli
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Andrea Bernardini
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Paulina Karen Mendoza Sanchez
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research, Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Elisabeth Scheer
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Mylène Damilot
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Karim Essabri
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Luc Negroni
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - Stéphane D. Vincent
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
| | - HT Marc Timmers
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research, Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - László Tora
- Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Medicale, U1258, Illkirch, France
- Universite de Strasbourg, Illkirch, France
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14
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Gasparski AN, Moissoglu K, Pallikkuth S, Meydan S, Guydosh NR, Mili S. mRNA location and translation rate determine protein targeting to dual destinations. Mol Cell 2023; 83:2726-2738.e9. [PMID: 37506697 PMCID: PMC10530421 DOI: 10.1016/j.molcel.2023.06.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 04/25/2023] [Accepted: 06/30/2023] [Indexed: 07/30/2023]
Abstract
Numerous proteins are targeted to two or multiple subcellular destinations where they exert distinct functional consequences. The balance between such differential targeting is thought to be determined post-translationally, relying on protein sorting mechanisms. Here, we show that mRNA location and translation rate can also determine protein targeting by modulating protein binding to specific interacting partners. Peripheral localization of the NET1 mRNA and fast translation lead to higher cytosolic retention of the NET1 protein by promoting its binding to the membrane-associated scaffold protein CASK. By contrast, perinuclear mRNA location and/or slower translation rate favor nuclear targeting by promoting binding to importins. This mRNA location-dependent mechanism is modulated by physiological stimuli and profoundly impacts NET1 function in cell motility. These results reveal that the location of protein synthesis and the rate of translation elongation act in coordination as a "partner-selection" mechanism that robustly influences protein distribution and function.
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Affiliation(s)
- Alexander N Gasparski
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sandeep Pallikkuth
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sezen Meydan
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA; National Institute of General Medical Sciences, NIH, Bethesda, MD 20892, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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15
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Bernardini A, Mukherjee P, Scheer E, Kamenova I, Antonova S, Mendoza Sanchez PK, Yayli G, Morlet B, Timmers HTM, Tora L. Hierarchical TAF1-dependent co-translational assembly of the basal transcription factor TFIID. Nat Struct Mol Biol 2023; 30:1141-1152. [PMID: 37386215 PMCID: PMC10442232 DOI: 10.1038/s41594-023-01026-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/31/2023] [Indexed: 07/01/2023]
Abstract
Large heteromeric multiprotein complexes play pivotal roles at every step of gene expression in eukaryotic cells. Among them, the 20-subunit basal transcription factor TFIID nucleates the RNA polymerase II preinitiation complex at gene promoters. Here, by combining systematic RNA-immunoprecipitation (RIP) experiments, single-molecule imaging, proteomics and structure-function analyses, we show that human TFIID biogenesis occurs co-translationally. We discovered that all protein heterodimerization steps happen during protein synthesis. We identify TAF1-the largest protein in the complex-as a critical factor for TFIID assembly. TAF1 acts as a flexible scaffold that drives the co-translational recruitment of TFIID submodules preassembled in the cytoplasm. Altogether, our data suggest a multistep hierarchical model for TFIID biogenesis that culminates with the co-translational assembly of the complex onto the nascent TAF1 polypeptide. We envision that this assembly strategy could be shared with other large heteromeric protein complexes.
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Affiliation(s)
- Andrea Bernardini
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Pooja Mukherjee
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Elisabeth Scheer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Ivanka Kamenova
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Nature Protocols, London, UK
| | - Simona Antonova
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
- The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Paulina Karen Mendoza Sanchez
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Gizem Yayli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - H T Marc Timmers
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - László Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.
- Centre National de la Recherche Scientifique, Illkirch, France.
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France.
- Université de Strasbourg, Illkirch, France.
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16
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Gasparski AN, Moissoglu K, Pallikkuth S, Meydan S, Guydosh NR, Mili S. mRNA Location and Translation Rate Determine Protein Targeting to Dual Destinations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538105. [PMID: 37163129 PMCID: PMC10168211 DOI: 10.1101/2023.04.24.538105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Numerous proteins are targeted to two or multiple subcellular destinations where they exert distinct functional consequences. The balance between such differential targeting is thought to be determined post-translationally, relying on protein sorting mechanisms. Here, we show that protein targeting can additionally be determined by mRNA location and translation rate, through modulating protein binding to specific interacting partners. Peripheral localization of the NET1 mRNA and fast translation lead to higher cytosolic retention of the NET1 protein, through promoting its binding to the membrane-associated scaffold protein CASK. By contrast, perinuclear mRNA location and/or slower translation rate favor nuclear targeting, through promoting binding to importins. This mRNA location-dependent mechanism is modulated by physiological stimuli and profoundly impacts NET1 function in cell motility. These results reveal that the location of protein synthesis and the rate of translation elongation act in coordination as a 'partner-selection' mechanism that robustly influences protein distribution and function.
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Affiliation(s)
- Alexander N. Gasparski
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, 20892, MD, USA
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, 20892, MD, USA
| | - Sandeep Pallikkuth
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, 20892, MD, USA
| | - Sezen Meydan
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, 20892, MD, USA
- National Institute of General Medical Sciences, NIH, Bethesda, 20892, MD, USA
| | - Nicholas R. Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, 20892, MD, USA
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, NIH, Bethesda, 20892, MD, USA
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17
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Bernardini A, Mukherjee P, Scheer E, Kamenova I, Antonova S, Sanchez PKM, Yayli G, Morlet B, Timmers HM, Tora L. Hierarchical TAF1-dependent co-translational assembly of the basal transcription factor TFIID. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.05.535704. [PMID: 37066372 PMCID: PMC10104070 DOI: 10.1101/2023.04.05.535704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Large heteromeric multiprotein complexes play pivotal roles at every step of gene expression in eukaryotic cells. Among them, the 20-subunit basal transcription factor TFIID nucleates RNA polymerase II preinitiation complex at gene promoters. Here, by combining systematic RNA-immunoprecipitation (RIP) experiments, single-molecule imaging, proteomics and structure-function analyses, we show that TFIID biogenesis occurs co-translationally. We discovered that all protein heterodimerization steps happen during protein synthesis. We identify TAF1 - the largest protein in the complex - as a critical factor for TFIID assembly. TAF1 acts as a flexible scaffold that drives the co-translational recruitment of TFIID submodules preassembled in the cytoplasm. Altogether, our data suggest a multistep hierarchical model for TFIID biogenesis that culminates with the co-translational assembly of the complex onto the nascent TAF1 polypeptide. We envision that this assembly strategy could be shared with other large heteromeric protein complexes.
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Affiliation(s)
- Andrea Bernardini
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Pooja Mukherjee
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Elisabeth Scheer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Ivanka Kamenova
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Simona Antonova
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Germany
| | - Paulina Karen Mendoza Sanchez
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Germany
| | - Gizem Yayli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - H.T. Marc Timmers
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Germany
| | - László Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
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18
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Sun C, Schuman E. A multi-omics view of neuronal subcellular protein synthesis. Curr Opin Neurobiol 2023; 80:102705. [PMID: 36913750 DOI: 10.1016/j.conb.2023.102705] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 03/13/2023]
Abstract
While it has long been known that protein synthesis is necessary for long-term memory in the brain, the logistics of neuronal protein synthesis is complicated by the extensive subcellular compartmentalization of the neuron. Local protein synthesis solves many of the logistic problems posed by the extreme complexity of dendritic and axonal arbors and the huge number of synapses. Here we review recent multi-omic and quantitative studies that elaborate a systems view of decentralized neuronal protein synthesis. We highlight recent insights from the transcriptomic, translatomic, and proteomic levels, discuss the nuanced logic of local protein synthesis for different protein features, and list the missing information needed to build a comprehensive logistic model for neuronal protein supply.
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Affiliation(s)
- Chao Sun
- Max Planck Institute for Brain Research, Frankfurt, Germany; Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Denmark; Aarhus University, Department of Molecular Biology and Genetics, Universitetsbyen 81, 8000 Aarhus C, Denmark. https://twitter.com/LukeChaoSun
| | - Erin Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany.
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19
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Morales-Polanco F, Lee JH, Barbosa NM, Frydman J. Cotranslational Mechanisms of Protein Biogenesis and Complex Assembly in Eukaryotes. Annu Rev Biomed Data Sci 2022; 5:67-94. [PMID: 35472290 PMCID: PMC11040709 DOI: 10.1146/annurev-biodatasci-121721-095858] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The formation of protein complexes is crucial to most biological functions. The cellular mechanisms governing protein complex biogenesis are not yet well understood, but some principles of cotranslational and posttranslational assembly are beginning to emerge. In bacteria, this process is favored by operons encoding subunits of protein complexes. Eukaryotic cells do not have polycistronic mRNAs, raising the question of how they orchestrate the encounter of unassembled subunits. Here we review the constraints and mechanisms governing eukaryotic co- and posttranslational protein folding and assembly, including the influence of elongation rate on nascent chain targeting, folding, and chaperone interactions. Recent evidence shows that mRNAs encoding subunits of oligomeric assemblies can undergo localized translation and form cytoplasmic condensates that might facilitate the assembly of protein complexes. Understanding the interplay between localized mRNA translation and cotranslational proteostasis will be critical to defining protein complex assembly in vivo.
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Affiliation(s)
| | - Jae Ho Lee
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Natália M Barbosa
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California, USA;
- Department of Genetics, Stanford University, Stanford, California, USA
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20
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pSNAP: Proteome-wide analysis of elongating nascent polypeptide chains. iScience 2022; 25:104516. [PMID: 35754732 PMCID: PMC9218386 DOI: 10.1016/j.isci.2022.104516] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 02/10/2022] [Accepted: 05/31/2022] [Indexed: 12/27/2022] Open
Abstract
Cellular global translation is often measured using ribosome profiling or quantitative mass spectrometry, but these methods do not provide direct information at the level of elongating nascent polypeptide chains (NPCs) and associated co-translational events. Here, we describe pSNAP, a method for proteome-wide profiling of NPCs by affinity enrichment of puromycin- and stable isotope-labeled polypeptides. pSNAP does not require ribosome purification and/or chemical labeling, and captures bona fide NPCs that characteristically exhibit protein N-terminus-biased positions. We applied pSNAP to evaluate the effect of silmitasertib, a potential molecular therapy for cancer, and revealed acute translational repression through casein kinase II and mTOR pathways. We also characterized modifications on NPCs and demonstrated that the combination of different types of modifications, such as acetylation and phosphorylation in the N-terminal region of histone H1.5, can modulate interactions with ribosome-associated factors. Thus, pSNAP provides a framework for dissecting co-translational regulations on a proteome-wide scale. Nascent polypeptidome analysis with a simplified protocol Quantification of acute changes in nascent polypeptides induced by external stimuli Profiling and characterization of chemical modifications on nascent polypeptides
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21
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Esposito E, Weidemann DE, Rogers JM, Morton CM, Baybay EK, Chen J, Hauf S. Mitotic checkpoint gene expression is tuned by codon usage bias. EMBO J 2022; 41:e107896. [PMID: 35811551 PMCID: PMC9340482 DOI: 10.15252/embj.2021107896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 11/09/2022] Open
Abstract
The mitotic checkpoint (also called spindle assembly checkpoint, SAC) is a signaling pathway that safeguards proper chromosome segregation. Correct functioning of the SAC depends on adequate protein concentrations and appropriate stoichiometries between SAC proteins. Yet very little is known about the regulation of SAC gene expression. Here, we show in the fission yeast Schizosaccharomyces pombe that a combination of short mRNA half-lives and long protein half-lives supports stable SAC protein levels. For the SAC genes mad2+ and mad3+ , their short mRNA half-lives are caused, in part, by a high frequency of nonoptimal codons. In contrast, mad1+ mRNA has a short half-life despite a higher frequency of optimal codons, and despite the lack of known RNA-destabilizing motifs. Hence, different SAC genes employ different strategies of expression. We further show that Mad1 homodimers form co-translationally, which may necessitate a certain codon usage pattern. Taken together, we propose that the codon usage of SAC genes is fine-tuned to ensure proper SAC function. Our work shines light on gene expression features that promote spindle assembly checkpoint function and suggests that synonymous mutations may weaken the checkpoint.
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Affiliation(s)
- Eric Esposito
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Douglas E Weidemann
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jessie M Rogers
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Claire M Morton
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Erod Keaton Baybay
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Silke Hauf
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
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22
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The Nuclear Pore Complex: Birth, Life, and Death of a Cellular Behemoth. Cells 2022; 11:cells11091456. [PMID: 35563762 PMCID: PMC9100368 DOI: 10.3390/cells11091456] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 02/01/2023] Open
Abstract
Nuclear pore complexes (NPCs) are the only transport channels that cross the nuclear envelope. Constructed from ~500–1000 nucleoporin proteins each, they are among the largest macromolecular assemblies in eukaryotic cells. Thanks to advances in structural analysis approaches, the construction principles and architecture of the NPC have recently been revealed at submolecular resolution. Although the overall structure and inventory of nucleoporins are conserved, NPCs exhibit significant compositional and functional plasticity even within single cells and surprising variability in their assembly pathways. Once assembled, NPCs remain seemingly unexchangeable in post-mitotic cells. There are a number of as yet unresolved questions about how the versatility of NPC assembly and composition is established, how cells monitor the functional state of NPCs or how they could be renewed. Here, we review current progress in our understanding of the key aspects of NPC architecture and lifecycle.
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23
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Seidel M, Becker A, Pereira F, Landry JJM, de Azevedo NTD, Fusco CM, Kaindl E, Romanov N, Baumbach J, Langer JD, Schuman EM, Patil KR, Hummer G, Benes V, Beck M. Co-translational assembly orchestrates competing biogenesis pathways. Nat Commun 2022; 13:1224. [PMID: 35264577 PMCID: PMC8907234 DOI: 10.1038/s41467-022-28878-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 02/11/2022] [Indexed: 12/27/2022] Open
Abstract
During the co-translational assembly of protein complexes, a fully synthesized subunit engages with the nascent chain of a newly synthesized interaction partner. Such events are thought to contribute to productive assembly, but their exact physiological relevance remains underexplored. Here, we examine structural motifs contained in nucleoporins for their potential to facilitate co-translational assembly. We experimentally test candidate structural motifs and identify several previously unknown co-translational interactions. We demonstrate by selective ribosome profiling that domain invasion motifs of beta-propellers, coiled-coils, and short linear motifs may act as co-translational assembly domains. Such motifs are often contained in proteins that are members of multiple complexes (moonlighters) and engage with closely related paralogs. Surprisingly, moonlighters and paralogs assemble co-translationally in only some but not all of the relevant biogenesis pathways. Our results highlight the regulatory complexity of assembly pathways.
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Affiliation(s)
- Maximilian Seidel
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
- Faculty of Bioscience, Heidelberg University, Heidelberg, Germany
| | - Anja Becker
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Filipa Pereira
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jonathan J M Landry
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Claudia M Fusco
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Eva Kaindl
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Natalie Romanov
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Janina Baumbach
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Julian D Langer
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt, Germany
- Membrane Proteomics and Mass Spectrometry, Max Planck Institute of Biophysics, Frankfurt, Germany
- Mass Spectrometry, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Erin M Schuman
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Kiran Raosaheb Patil
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Medical Research Council Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany
- Institute of Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Martin Beck
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany.
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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24
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Cotranslational interaction of human EBP50 and ezrin overcomes masked binding site during complex assembly. Proc Natl Acad Sci U S A 2022; 119:2115799119. [PMID: 35140182 PMCID: PMC8851480 DOI: 10.1073/pnas.2115799119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2021] [Indexed: 12/13/2022] Open
Abstract
Multiprotein assemblages are the intracellular workhorses of many physiological processes. Assembly of constituents into complexes can be driven by stochastic, domain-dependent, posttranslational events in which mature, folded proteins specifically interact. However, inaccessibility of interacting surfaces in mature proteins (e.g., due to "buried" domains) can obstruct complex formation. Mechanisms by which multiprotein complex constituents overcome topological impediments remain enigmatic. For example, the heterodimeric complex formed by EBP50 and ezrin must address this issue as the EBP50-interacting domain in ezrin is obstructed by a self-interaction that occupies the EBP50 binding site. Here, we show that the EBP50-ezrin complex is formed by a cotranslational mechanism in which the C terminus of mature, fully formed EBP50 binds the emerging, ribosome-bound N-terminal FERM domain of ezrin during EZR mRNA translation. Consistent with this observation, a C-terminal EBP50 peptide mimetic reduces the cotranslational interaction and abrogates EBP50-ezrin complex formation. Phosphorylation of EBP50 at Ser339 and Ser340 abrogates the cotranslational interaction and inhibits complex formation. In summary, we show that the function of eukaryotic mRNA translation extends beyond "simple" generation of a linear peptide chain that folds into a tertiary structure, potentially for subsequent complex assembly; importantly, translation can facilitate interactions with sterically inaccessible domains to form functional multiprotein complexes.
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25
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Gasparski AN, Mason DE, Moissoglu K, Mili S. Regulation and outcomes of localized RNA translation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1721. [PMID: 35166036 PMCID: PMC9787767 DOI: 10.1002/wrna.1721] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/18/2022] [Accepted: 01/22/2022] [Indexed: 12/31/2022]
Abstract
Spatial segregation of mRNAs in the cytoplasm of cells is a well-known biological phenomenon that is widely observed in diverse species spanning different kingdoms of life. In mammalian cells, localization of mRNAs has been documented and studied quite extensively in highly polarized cells, most notably in neurons, where localized mRNAs function to direct protein production at sites that are quite distant from the soma. Recent studies have strikingly revealed that a large proportion of the cellular transcriptome exhibits polarized distributions even in cells that lack an obvious need for long-range transport, such as fibroblasts or epithelial cells. This review focuses on emerging concepts regarding the functional outcomes of mRNA targeting in the cytoplasm of such cells. We also discuss regulatory mechanisms controlling these events, with an emphasis on the role of cell mechanics and the organization of the cytoskeleton. This article is categorized under: Translation > Regulation RNA Export and Localization > RNA Localization.
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Affiliation(s)
- Alexander N. Gasparski
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Devon E. Mason
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
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26
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Müntjes K, Devan SK, Reichert AS, Feldbrügge M. Linking transport and translation of mRNAs with endosomes and mitochondria. EMBO Rep 2021; 22:e52445. [PMID: 34402186 PMCID: PMC8490996 DOI: 10.15252/embr.202152445] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/06/2021] [Accepted: 07/27/2021] [Indexed: 01/01/2023] Open
Abstract
In eukaryotic cells, proteins are targeted to their final subcellular locations with precise timing. A key underlying mechanism is the active transport of cognate mRNAs, which in many systems can be linked intimately to membrane trafficking. A prominent example is the long-distance endosomal transport of mRNAs and their local translation. Here, we describe current highlights of fundamental mechanisms of the underlying transport process as well as of biological functions ranging from endosperm development in plants to fungal pathogenicity and neuronal processes. Translation of endosome-associated mRNAs often occurs at the cytoplasmic surface of endosomes, a process that is needed for membrane-assisted formation of heteromeric protein complexes and for accurate subcellular targeting of proteins. Importantly, endosome-coupled translation of mRNAs encoding mitochondrial proteins, for example, seems to be particularly important for efficient organelle import and for regulating subcellular mitochondrial activity. In essence, these findings reveal a new mechanism of loading newly synthesised proteins onto endocytic membranes enabling intimate crosstalk between organelles. The novel link between endosomes and mitochondria adds an inspiring new level of complexity to trafficking and organelle biology.
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Affiliation(s)
- Kira Müntjes
- Institute of MicrobiologyCluster of Excellence on Plant SciencesHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Senthil Kumar Devan
- Institute of MicrobiologyCluster of Excellence on Plant SciencesHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology IMedical Faculty and University Hospital DüsseldorfHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Michael Feldbrügge
- Institute of MicrobiologyCluster of Excellence on Plant SciencesHeinrich Heine University DüsseldorfDüsseldorfGermany
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27
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To P, Whitehead B, Tarbox HE, Fried SD. Nonrefoldability is Pervasive Across the E. coli Proteome. J Am Chem Soc 2021; 143:11435-11448. [PMID: 34308638 DOI: 10.1021/jacs.1c03270] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Decades of research on protein folding have primarily focused on a subset of small proteins that can reversibly refold from a denatured state. However, these studies have generally not been representative of the complexity of natural proteomes, which consist of many proteins with complex architectures and domain organizations. Here, we introduce an experimental approach to probe protein refolding kinetics for whole proteomes using mass spectrometry-based proteomics. Our study covers the majority of the soluble E. coli proteome expressed during log-phase growth, and among this group, we find that one-third of the E. coli proteome is not intrinsically refoldable on physiological time scales, a cohort that is enriched with certain fold-types, domain organizations, and other biophysical features. We also identify several properties and fold-types that are correlated with slow refolding on the minute time scale. Hence, these results illuminate when exogenous factors and processes, such as chaperones or cotranslational folding, might be required for efficient protein folding.
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Affiliation(s)
- Philip To
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Briana Whitehead
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Haley E Tarbox
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Stephen D Fried
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.,Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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28
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Lashkevich KA, Dmitriev SE. mRNA Targeting, Transport and Local Translation in Eukaryotic Cells: From the Classical View to a Diversity of New Concepts. Mol Biol 2021; 55:507-537. [PMID: 34092811 PMCID: PMC8164833 DOI: 10.1134/s0026893321030080] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 02/26/2021] [Accepted: 03/12/2021] [Indexed: 12/28/2022]
Abstract
Spatial organization of protein biosynthesis in the eukaryotic cell has been studied for more than fifty years, thus many facts have already been included in textbooks. According to the classical view, mRNA transcripts encoding secreted and transmembrane proteins are translated by ribosomes associated with endoplasmic reticulum membranes, while soluble cytoplasmic proteins are synthesized on free polysomes. However, in the last few years, new data has emerged, revealing selective translation of mRNA on mitochondria and plastids, in proximity to peroxisomes and endosomes, in various granules and at the cytoskeleton (actin network, vimentin intermediate filaments, microtubules and centrosomes). There are also long-standing debates about the possibility of protein synthesis in the nucleus. Localized translation can be determined by targeting signals in the synthesized protein, nucleotide sequences in the mRNA itself, or both. With RNA-binding proteins, many transcripts can be assembled into specific RNA condensates and form RNP particles, which may be transported by molecular motors to the sites of active translation, form granules and provoke liquid-liquid phase separation in the cytoplasm, both under normal conditions and during cell stress. The translation of some mRNAs occurs in specialized "translation factories," assemblysomes, transperons and other structures necessary for the correct folding of proteins, interaction with functional partners and formation of oligomeric complexes. Intracellular localization of mRNA has a significant impact on the efficiency of its translation and presumably determines its response to cellular stress. Compartmentalization of mRNAs and the translation machinery also plays an important role in viral infections. Many viruses provoke the formation of specific intracellular structures, virus factories, for the production of their proteins. Here we review the current concepts of the molecular mechanisms of transport, selective localization and local translation of cellular and viral mRNAs, their effects on protein targeting and topogenesis, and on the regulation of protein biosynthesis in different compartments of the eukaryotic cell. Special attention is paid to new systems biology approaches, providing new cues to the study of localized translation.
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Affiliation(s)
- Kseniya A Lashkevich
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119234 Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Moscow State University, 119234 Moscow, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119234 Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Moscow State University, 119234 Moscow, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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29
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Koubek J, Schmitt J, Galmozzi CV, Kramer G. Mechanisms of Cotranslational Protein Maturation in Bacteria. Front Mol Biosci 2021; 8:689755. [PMID: 34113653 PMCID: PMC8185961 DOI: 10.3389/fmolb.2021.689755] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/10/2021] [Indexed: 01/05/2023] Open
Abstract
Growing cells invest a significant part of their biosynthetic capacity into the production of proteins. To become functional, newly-synthesized proteins must be N-terminally processed, folded and often translocated to other cellular compartments. A general strategy is to integrate these protein maturation processes with translation, by cotranslationally engaging processing enzymes, chaperones and targeting factors with the nascent polypeptide. Precise coordination of all factors involved is critical for the efficiency and accuracy of protein synthesis and cellular homeostasis. This review provides an overview of the current knowledge on cotranslational protein maturation, with a focus on the production of cytosolic proteins in bacteria. We describe the role of the ribosome and the chaperone network in protein folding and how the dynamic interplay of all cotranslationally acting factors guides the sequence of cotranslational events. Finally, we discuss recent data demonstrating the coupling of protein synthesis with the assembly of protein complexes and end with a brief discussion of outstanding questions and emerging concepts in the field of cotranslational protein maturation.
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Affiliation(s)
- Jiří Koubek
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jaro Schmitt
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Carla Veronica Galmozzi
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Günter Kramer
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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30
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Turowski TW, Boguta M. Specific Features of RNA Polymerases I and III: Structure and Assembly. Front Mol Biosci 2021; 8:680090. [PMID: 34055890 PMCID: PMC8160253 DOI: 10.3389/fmolb.2021.680090] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/16/2021] [Indexed: 12/22/2022] Open
Abstract
RNA polymerase I (RNAPI) and RNAPIII are multi-heterogenic protein complexes that specialize in the transcription of highly abundant non-coding RNAs, such as ribosomal RNA (rRNA) and transfer RNA (tRNA). In terms of subunit number and structure, RNAPI and RNAPIII are more complex than RNAPII that synthesizes thousands of different mRNAs. Specific subunits of the yeast RNAPI and RNAPIII form associated subcomplexes that are related to parts of the RNAPII initiation factors. Prior to their delivery to the nucleus where they function, RNAP complexes are assembled at least partially in the cytoplasm. Yeast RNAPI and RNAPIII share heterodimer Rpc40-Rpc19, a functional equivalent to the αα homodimer which initiates assembly of prokaryotic RNAP. In the process of yeast RNAPI and RNAPIII biogenesis, Rpc40 and Rpc19 form the assembly platform together with two small, bona fide eukaryotic subunits, Rpb10 and Rpb12. We propose that this assembly platform is co-translationally seeded while the Rpb10 subunit is synthesized by cytoplasmic ribosome machinery. The translation of Rpb10 is stimulated by Rbs1 protein, which binds to the 3′-untranslated region of RPB10 mRNA and hypothetically brings together Rpc19 and Rpc40 subunits to form the αα-like heterodimer. We suggest that such a co-translational mechanism is involved in the assembly of RNAPI and RNAPIII complexes.
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Affiliation(s)
- Tomasz W Turowski
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Magdalena Boguta
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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31
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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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32
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Lautier O, Penzo A, Rouvière JO, Chevreux G, Collet L, Loïodice I, Taddei A, Devaux F, Collart MA, Palancade B. Co-translational assembly and localized translation of nucleoporins in nuclear pore complex biogenesis. Mol Cell 2021; 81:2417-2427.e5. [PMID: 33838103 DOI: 10.1016/j.molcel.2021.03.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/24/2021] [Accepted: 03/18/2021] [Indexed: 01/03/2023]
Abstract
mRNA translation is coupled to multiprotein complex assembly in the cytoplasm or to protein delivery into intracellular compartments. Here, by combining systematic RNA immunoprecipitation and single-molecule RNA imaging in yeast, we have provided a complete depiction of the co-translational events involved in the biogenesis of a large multiprotein assembly, the nuclear pore complex (NPC). We report that binary interactions between NPC subunits can be established during translation, in the cytoplasm. Strikingly, the nucleoporins Nup1/Nup2, together with a number of nuclear proteins, are instead translated at nuclear pores, through a mechanism involving interactions between their nascent N-termini and nuclear transport receptors. Uncoupling this co-translational recruitment further triggers the formation of cytoplasmic foci of unassembled polypeptides. Altogether, our data reveal that distinct, spatially segregated modes of co-translational interactions foster the ordered assembly of NPC subunits and that localized translation can ensure the proper delivery of proteins to the pore and the nucleus.
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Affiliation(s)
- Ophélie Lautier
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Arianna Penzo
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Jérôme O Rouvière
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Guillaume Chevreux
- ProteoSeine@IJM, Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Louis Collet
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Isabelle Loïodice
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, UMR3664 Nuclear Dynamics, Paris, France
| | - Angela Taddei
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, UMR3664 Nuclear Dynamics, Paris, France
| | - Frédéric Devaux
- Sorbonne Université, CNRS, Institut de biologie Paris-Seine (IBPS), UMR 7238, Laboratoire de biologie computationnelle et quantitative, LCQB, 4 place Jussieu, 75005 Paris, France
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Benoit Palancade
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France.
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33
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Swamy KBS, Schuyler SC, Leu JY. Protein Complexes Form a Basis for Complex Hybrid Incompatibility. Front Genet 2021; 12:609766. [PMID: 33633780 PMCID: PMC7900514 DOI: 10.3389/fgene.2021.609766] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/20/2021] [Indexed: 12/20/2022] Open
Abstract
Proteins are the workhorses of the cell and execute many of their functions by interacting with other proteins forming protein complexes. Multi-protein complexes are an admixture of subunits, change their interaction partners, and modulate their functions and cellular physiology in response to environmental changes. When two species mate, the hybrid offspring are usually inviable or sterile because of large-scale differences in the genetic makeup between the two parents causing incompatible genetic interactions. Such reciprocal-sign epistasis between inter-specific alleles is not limited to incompatible interactions between just one gene pair; and, usually involves multiple genes. Many of these multi-locus incompatibilities show visible defects, only in the presence of all the interactions, making it hard to characterize. Understanding the dynamics of protein-protein interactions (PPIs) leading to multi-protein complexes is better suited to characterize multi-locus incompatibilities, compared to studying them with traditional approaches of genetics and molecular biology. The advances in omics technologies, which includes genomics, transcriptomics, and proteomics can help achieve this end. This is especially relevant when studying non-model organisms. Here, we discuss the recent progress in the understanding of hybrid genetic incompatibility; omics technologies, and how together they have helped in characterizing protein complexes and in turn multi-locus incompatibilities. We also review advances in bioinformatic techniques suitable for this purpose and propose directions for leveraging the knowledge gained from model-organisms to identify genetic incompatibilities in non-model organisms.
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Affiliation(s)
- Krishna B. S. Swamy
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, India
| | - Scott C. Schuyler
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Division of Head and Neck Surgery, Department of Otolaryngology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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34
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Minehart JA, Speer CM. A Picture Worth a Thousand Molecules-Integrative Technologies for Mapping Subcellular Molecular Organization and Plasticity in Developing Circuits. Front Synaptic Neurosci 2021; 12:615059. [PMID: 33469427 PMCID: PMC7813761 DOI: 10.3389/fnsyn.2020.615059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
A key challenge in developmental neuroscience is identifying the local regulatory mechanisms that control neurite and synaptic refinement over large brain volumes. Innovative molecular techniques and high-resolution imaging tools are beginning to reshape our view of how local protein translation in subcellular compartments drives axonal, dendritic, and synaptic development and plasticity. Here we review recent progress in three areas of neurite and synaptic study in situ-compartment-specific transcriptomics/translatomics, targeted proteomics, and super-resolution imaging analysis of synaptic organization and development. We discuss synergies between sequencing and imaging techniques for the discovery and validation of local molecular signaling mechanisms regulating synaptic development, plasticity, and maintenance in circuits.
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Affiliation(s)
| | - Colenso M. Speer
- Department of Biology, University of Maryland, College Park, MD, United States
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35
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Abstract
Translation is a central biological process in living cells. Ribosome profiling approach enables assessing translation on a global, cell-wide level. Extracting versatile information from the ribosome profiling data usually requires specialized expertise for handling the sequencing data that is not available to the broad community of experimentalists. Here, we provide an easy-to-use and modifiable workflow that uses a small set of commands and enables full data analysis in a standardized way, including precise positioning of the ribosome-protected fragments, for determining codon-specific translation features. The workflow is complemented with simple step-by-step explanations and is accessible to scientists with no computational background.
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Affiliation(s)
| | - Zoya Ignatova
- Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany.
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36
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Cieśla M, Turowski TW, Nowotny M, Tollervey D, Boguta M. The expression of Rpb10, a small subunit common to RNA polymerases, is modulated by the R3H domain-containing Rbs1 protein and the Upf1 helicase. Nucleic Acids Res 2020; 48:12252-12268. [PMID: 33231687 PMCID: PMC7708074 DOI: 10.1093/nar/gkaa1069] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/05/2020] [Accepted: 10/22/2020] [Indexed: 01/07/2023] Open
Abstract
The biogenesis of eukaryotic RNA polymerases is poorly understood. The present study used a combination of genetic and molecular approaches to explore the assembly of RNA polymerase III (Pol III) in yeast. We identified a regulatory link between Rbs1, a Pol III assembly factor, and Rpb10, a small subunit that is common to three RNA polymerases. Overexpression of Rbs1 increased the abundance of both RPB10 mRNA and the Rpb10 protein, which correlated with suppression of Pol III assembly defects. Rbs1 is a poly(A)mRNA-binding protein and mutational analysis identified R3H domain to be required for mRNA interactions and genetic enhancement of Pol III biogenesis. Rbs1 also binds to Upf1 protein, a key component in nonsense-mediated mRNA decay (NMD) and levels of RPB10 mRNA were increased in a upf1Δ strain. Genome-wide RNA binding by Rbs1 was characterized by UV cross-linking based approach. We demonstrated that Rbs1 directly binds to the 3' untranslated regions (3'UTRs) of many mRNAs including transcripts encoding Pol III subunits, Rpb10 and Rpc19. We propose that Rbs1 functions by opposing mRNA degradation, at least in part mediated by NMD pathway. Orthologues of Rbs1 protein are present in other eukaryotes, including humans, suggesting that this is a conserved regulatory mechanism.
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Affiliation(s)
- Małgorzata Cieśla
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Tomasz W Turowski
- Wellcome Centre for Cell Biology, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - David Tollervey
- Wellcome Centre for Cell Biology, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106 Warsaw, Poland
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37
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Friedl J, Knopp MR, Groh C, Paz E, Gould SB, Herrmann JM, Boos F. More than just a ticket canceller: the mitochondrial processing peptidase tailors complex precursor proteins at internal cleavage sites. Mol Biol Cell 2020; 31:2657-2668. [PMID: 32997570 PMCID: PMC8734313 DOI: 10.1091/mbc.e20-08-0524] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/21/2020] [Accepted: 09/25/2020] [Indexed: 11/11/2022] Open
Abstract
Most mitochondrial proteins are synthesized as precursors that carry N-terminal presequences. After they are imported into mitochondria, these targeting signals are cleaved off by the mitochondrial processing peptidase (MPP). Using the mitochondrial tandem protein Arg5,6 as a model substrate, we demonstrate that MPP has an additional role in preprotein maturation, beyond the removal of presequences. Arg5,6 is synthesized as a polyprotein precursor that is imported into mitochondria and subsequently separated into two distinct enzymes. This internal processing is performed by MPP, which cleaves the Arg5,6 precursor at its N-terminus and at an internal site. The peculiar organization of Arg5,6 is conserved across fungi and reflects the polycistronic arginine operon in prokaryotes. MPP cleavage sites are also present in other mitochondrial fusion proteins from fungi, plants, and animals. Hence, besides its role as a "ticket canceller" for removal of presequences, MPP exhibits a second conserved activity as an internal processing peptidase for complex mitochondrial precursor proteins.
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Affiliation(s)
- Jana Friedl
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Michael R. Knopp
- Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Carina Groh
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Eyal Paz
- Departments of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sven B. Gould
- Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Johannes M. Herrmann
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Felix Boos
- Cell Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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38
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Sun S, Mariappan M. C-terminal tail length guides insertion and assembly of membrane proteins. J Biol Chem 2020; 295:15498-15510. [PMID: 32878985 DOI: 10.1074/jbc.ra120.012992] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/27/2020] [Indexed: 11/06/2022] Open
Abstract
A large number of newly synthesized membrane proteins in the endoplasmic reticulum (ER) are assembled into multiprotein complexes, but little is known about the mechanisms required for assembly membrane proteins. It has been suggested that membrane chaperones might exist, akin to the molecular chaperones that stabilize and direct the assembly of soluble protein complexes, but the mechanisms by which these proteins would bring together membrane protein components is unclear. Here, we have identified that the tail length of the C-terminal transmembrane domains (C-TMDs) determines efficient insertion and assembly of membrane proteins in the ER. We found that membrane proteins with C-TMD tails shorter than ∼60 amino acids are poorly inserted into the ER membrane, which suggests that translation is terminated before they are recognized by the Sec61 translocon for insertion. These C-TMDs with insufficient hydrophobicity are post-translationally recognized and retained by the Sec61 translocon complex, providing a time window for efficient assembly with TMDs from partner proteins. Retained TMDs that fail to assemble with their cognate TMDs are slowly translocated into the ER lumen and are recognized by the ER-associated degradation (ERAD) pathway for removal. In contrast, C-TMDs with sufficient hydrophobicity or tails longer than ∼80 residues are quickly released from the Sec61 translocon into the membrane or the ER lumen, resulting in inefficient assembly with partner TMDs. Thus, our data suggest that C-terminal tails harbor crucial signals for both the insertion and assembly of membrane proteins.
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Affiliation(s)
- Sha Sun
- Frome the Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, Connecticut, USA
| | - Malaiyalam Mariappan
- Frome the Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, Connecticut, USA.
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39
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Kalman ZE, Mészáros B, Gáspári Z, Dobson L. Distribution of disease-causing germline mutations in coiled-coils implies an important role of their N-terminal region. Sci Rep 2020; 10:17333. [PMID: 33060664 PMCID: PMC7562717 DOI: 10.1038/s41598-020-74354-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/21/2020] [Indexed: 11/08/2022] Open
Abstract
Next-generation sequencing resulted in the identification of a huge number of naturally occurring variations in human proteins. The correct interpretation of the functional effects of these variations necessitates the understanding of how they modulate protein structure. Coiled-coils are α-helical structures responsible for a diverse range of functions, but most importantly, they facilitate the structural organization of macromolecular scaffolds via oligomerization. In this study, we analyzed a comprehensive set of disease-associated germline mutations in coiled-coil structures. Our results suggest an important role of residues near the N-terminal part of coiled-coil regions, possibly critical for superhelix assembly and folding in some cases. We also show that coiled-coils of different oligomerization states exhibit characteristically distinct patterns of disease-causing mutations. Our study provides structural and functional explanations on how disease emerges through the mutation of these structural motifs.
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Affiliation(s)
- Zsofia E Kalman
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50/A, 1083, Budapest, Hungary
- 3in-PPCU Research Group, 2500, Esztergom, Hungary
| | - Bálint Mészáros
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Zoltán Gáspári
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50/A, 1083, Budapest, Hungary.
| | - Laszlo Dobson
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50/A, 1083, Budapest, Hungary.
- Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117, Budapest, Hungary.
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40
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Fujiwara K, Katagi Y, Ito K, Chiba S. Proteome-wide Capture of Co-translational Protein Dynamics in Bacillus subtilis Using TnDR, a Transposable Protein-Dynamics Reporter. Cell Rep 2020; 33:108250. [DOI: 10.1016/j.celrep.2020.108250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/03/2020] [Accepted: 09/17/2020] [Indexed: 11/29/2022] Open
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41
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Leddon SA, Fettis MM, Abramo K, Kelly R, Oleksyn D, Miller J. The CD28 Transmembrane Domain Contains an Essential Dimerization Motif. Front Immunol 2020; 11:1519. [PMID: 32765524 PMCID: PMC7378745 DOI: 10.3389/fimmu.2020.01519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
CD28 plays a critical role in regulating immune responses both by enhancing effector T cell activation and differentiation and controlling the development and function of regulatory T cells. CD28 is expressed at the cell surface as a disulfide linked homodimer that is thought to bind ligand monovalently. How ligand binding triggers CD28 to induce intracellular signaling as well as the proximal signaling pathways that are induced are not well-understood. In addition, recent data suggest inside-out signaling initiated by the T cell antigen receptor can enhance CD28 ligand binding, possibly by inducing a rearrangement of the CD28 dimer interface to allow for bivalent binding. To understand how possible conformational changes during ligand-induced receptor triggering and inside-out signaling are mediated, we examined the CD28 transmembrane domain. We identified an evolutionarily conserved YxxxxT motif that is shared with CTLA-4 and resembles the transmembrane dimerization motif within CD3ζ. We show that the CD28 transmembrane domain can drive protein dimerization in a bacterial expression system at levels equivalent to the well-known glycophorin A transmembrane dimerization motif. In addition, ectopic expression of the CD28 transmembrane domain into monomeric human CD25 can drive dimerization in murine T cells as detected by an increase in FRET by flow cytometry. Mutation of the polar YxxxxT motif to hydrophobic leucine residues (Y145L/T150L) attenuated CD28 transmembrane mediated dimerization in both the bacterial and mammalian assays. Introduction of the Y145L/T150L mutation of the CD28 transmembrane dimerization motif into the endogenous CD28 locus by CRISPR resulted in a dramatic loss in CD28 cell surface expression. These data suggest that under physiological conditions the YxxxxT dimerization motif within the CD28 transmembrane domain plays a critical role in the assembly and/or expression of stable CD28 dimers at the cell surface.
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Affiliation(s)
- Scott A Leddon
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Margaret M Fettis
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Kristin Abramo
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Ryan Kelly
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - David Oleksyn
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Jim Miller
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
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42
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Taggart JC, Zauber H, Selbach M, Li GW, McShane E. Keeping the Proportions of Protein Complex Components in Check. Cell Syst 2020; 10:125-132. [PMID: 32105631 PMCID: PMC7195860 DOI: 10.1016/j.cels.2020.01.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/17/2020] [Accepted: 01/29/2020] [Indexed: 02/07/2023]
Abstract
How do cells maintain relative proportions of protein complex components? Advances in quantitative, genome-wide measurements have begun to shed light onto the roles of protein synthesis and degradation in establishing the precise proportions in living cells: on the one hand, ribosome profiling studies indicate that proteins are already produced in the correct relative proportions. On the other hand, proteomic studies found that many complexes contain subunits that are made in excess and subsequently degraded. Here, we discuss these seemingly contradictory findings, emerging principles, and remaining open questions. We conclude that establishing precise protein levels involves both coordinated synthesis and post-translational fine-tuning via protein degradation.
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Affiliation(s)
| | - Henrik Zauber
- Proteome dynamics, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13092 Berlin, Germany
| | - Matthias Selbach
- Proteome dynamics, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13092 Berlin, Germany.
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
| | - Erik McShane
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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43
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Analysis of the co-translational assembly of the fungal fatty acid synthase (FAS). Sci Rep 2020; 10:895. [PMID: 31964902 PMCID: PMC6972935 DOI: 10.1038/s41598-020-57418-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/28/2019] [Indexed: 11/16/2022] Open
Abstract
The yeast fatty acid synthase (FAS) is a barrel-shaped 2.6 MDa complex. Upon barrel-formation, two multidomain subunits, each more than 200 kDa large, intertwine to form a heterododecameric complex that buries 170,000 Å2 of protein surface. In spite of the rich knowledge about yeast FAS in structure and function, its assembly remained elusive until recently, when co-translational interaction of the β-subunit with the nascent α-subunit was found to initiate assembly. Here, we characterize the co-translational assembly of yeast FAS at a molecular level. We show that the co-translationally formed interface is sensitive to subtle perturbations, so that the exchange of two amino acids located in the emerging interface can prevent assembly. On the other hand, assembly can also be initiated via the co-translational interaction of the subunits at other sites, which implies that this process is not strictly site or sequence specific. We further highlight additional steps in the biogenesis of yeast FAS, as the formation of a dimeric subunit that orchestrates complex formation and acts as platform for post-translational phosphopantetheinylation. The presented data supports the understanding of the recently discovered prevalence of eukaryotic complexes for co-translational assembly, and is valuable for further harnessing FAS in the biotechnological production of aliphatic compounds.
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44
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Cotranslational Folding of Proteins on the Ribosome. Biomolecules 2020; 10:biom10010097. [PMID: 31936054 PMCID: PMC7023365 DOI: 10.3390/biom10010097] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/20/2019] [Accepted: 12/25/2019] [Indexed: 02/04/2023] Open
Abstract
Many proteins in the cell fold cotranslationally within the restricted space of the polypeptide exit tunnel or at the surface of the ribosome. A growing body of evidence suggests that the ribosome can alter the folding trajectory in many different ways. In this review, we summarize the recent examples of how translation affects folding of single-domain, multiple-domain and oligomeric proteins. The vectorial nature of translation, the spatial constraints of the exit tunnel, and the electrostatic properties of the ribosome-nascent peptide complex define the onset of early folding events. The ribosome can facilitate protein compaction, induce the formation of intermediates that are not observed in solution, or delay the onset of folding. Examples of single-domain proteins suggest that early compaction events can define the folding pathway for some types of domain structures. Folding of multi-domain proteins proceeds in a domain-wise fashion, with each domain having its role in stabilizing or destabilizing neighboring domains. Finally, the assembly of protein complexes can also begin cotranslationally. In all these cases, the ribosome helps the nascent protein to attain a native fold and avoid the kinetic traps of misfolding.
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45
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3' UTRs Regulate Protein Functions by Providing a Nurturing Niche during Protein Synthesis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:95-104. [PMID: 31900325 DOI: 10.1101/sqb.2019.84.039206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Messenger RNAs (mRNAs) are the templates for protein synthesis as the coding region is translated into the amino acid sequence. mRNAs also contain 3' untranslated regions (3' UTRs) that harbor additional elements for the regulation of protein function. If the amino acid sequence of a protein is necessary and sufficient for its function, we call it 3' UTR-independent. In contrast, functions that are accomplished by protein complexes whose formation requires the presence of a specific 3' UTR are 3' UTR-dependent protein functions. We showed that 3' UTRs can regulate protein activity without affecting protein abundance, and alternative 3' UTRs can diversify protein functions. We currently think that the regulation of protein function by 3' UTRs is facilitated by the local environment at the site of protein synthesis, which we call the nurturing niche for nascent proteins. This niche is composed of the mRNA and the bound proteins that consist of RNA-binding proteins and recruited proteins. It enables the formation of specific protein complexes, as was shown for TIS granules, a recently discovered cytoplasmic membraneless organelle. This finding suggests that changing the niche for nascent proteins will alter protein activity and function, implying that cytoplasmic membraneless organelles can regulate protein function in a manner that is independent of protein abundance.
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