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Chen S, Collart MA. Membrane-associated mRNAs: A Post-transcriptional Pathway for Fine-turning Gene Expression. J Mol Biol 2024; 436:168579. [PMID: 38648968 DOI: 10.1016/j.jmb.2024.168579] [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: 10/30/2023] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Gene expression is a fundamental and highly regulated process involving a series of tightly coordinated steps, including transcription, post-transcriptional processing, translation, and post-translational modifications. A growing number of studies have revealed an additional layer of complexity in gene expression through the phenomenon of mRNA subcellular localization. mRNAs can be organized into membraneless subcellular structures within both the cytoplasm and the nucleus, but they can also targeted to membranes. In this review, we will summarize in particular our knowledge on localization of mRNAs to organelles, focusing on important regulators and available techniques for studying organellar localization, and significance of this localization in the broader context of gene expression regulation.
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Affiliation(s)
- Siyu Chen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
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2
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Jung M, Zimmermann R. Quantitative Mass Spectrometry Characterizes Client Spectra of Components for Targeting of Membrane Proteins to and Their Insertion into the Membrane of the Human ER. Int J Mol Sci 2023; 24:14166. [PMID: 37762469 PMCID: PMC10532041 DOI: 10.3390/ijms241814166] [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: 08/09/2023] [Revised: 09/07/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
To elucidate the redundancy in the components for the targeting of membrane proteins to the endoplasmic reticulum (ER) and/or their insertion into the ER membrane under physiological conditions, we previously analyzed different human cells by label-free quantitative mass spectrometry. The HeLa and HEK293 cells had been depleted of a certain component by siRNA or CRISPR/Cas9 treatment or were deficient patient fibroblasts and compared to the respective control cells by differential protein abundance analysis. In addition to clients of the SRP and Sec61 complex, we identified membrane protein clients of components of the TRC/GET, SND, and PEX3 pathways for ER targeting, and Sec62, Sec63, TRAM1, and TRAP as putative auxiliary components of the Sec61 complex. Here, a comprehensive evaluation of these previously described differential protein abundance analyses, as well as similar analyses on the Sec61-co-operating EMC and the characteristics of the topogenic sequences of the various membrane protein clients, i.e., the client spectra of the components, are reported. As expected, the analysis characterized membrane protein precursors with cleavable amino-terminal signal peptides or amino-terminal transmembrane helices as predominant clients of SRP, as well as the Sec61 complex, while precursors with more central or even carboxy-terminal ones were found to dominate the client spectra of the SND and TRC/GET pathways for membrane targeting. For membrane protein insertion, the auxiliary Sec61 channel components indeed share the client spectra of the Sec61 complex to a large extent. However, we also detected some unexpected differences, particularly related to EMC, TRAP, and TRAM1. The possible mechanistic implications for membrane protein biogenesis at the human ER are discussed and can be expected to eventually advance our understanding of the mechanisms that are involved in the so-called Sec61-channelopathies, resulting from deficient ER protein import.
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Affiliation(s)
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany;
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3
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Nguyen T, Mills JC, Cho CJ. The coordinated management of ribosome and translation during injury and regeneration. Front Cell Dev Biol 2023; 11:1186638. [PMID: 37427381 PMCID: PMC10325863 DOI: 10.3389/fcell.2023.1186638] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Diverse acute and chronic injuries induce damage responses in the gastrointestinal (GI) system, and numerous cell types in the gastrointestinal tract demonstrate remarkable resilience, adaptability, and regenerative capacity in response to stress. Metaplasias, such as columnar and secretory cell metaplasia, are well-known adaptations that these cells make, the majority of which are epidemiologically associated with an elevated cancer risk. On a number of fronts, it is now being investigated how cells respond to injury at the tissue level, where diverse cell types that differ in proliferation capacity and differentiation state cooperate and compete with one another to participate in regeneration. In addition, the cascades or series of molecular responses that cells show are just beginning to be understood. Notably, the ribosome, a ribonucleoprotein complex that is essential for translation on the endoplasmic reticulum (ER) and in the cytoplasm, is recognized as the central organelle during this process. The highly regulated management of ribosomes as key translational machinery, and their platform, rough endoplasmic reticulum, are not only essential for maintaining differentiated cell identity, but also for achieving successful cell regeneration after injury. This review will cover in depth how ribosomes, the endoplasmic reticulum, and translation are regulated and managed in response to injury (e.g., paligenosis), as well as why this is essential for the proper adaptation of a cell to stress. For this, we will first discuss how multiple gastrointestinal organs respond to stress through metaplasia. Next, we will cover how ribosomes are generated, maintained, and degraded, in addition to the factors that govern translation. Finally, we will investigate how ribosomes and translation machinery are dynamically regulated in response to injury. Our increased understanding of this overlooked cell fate decision mechanism will facilitate the discovery of novel therapeutic targets for gastrointestinal tract tumors, focusing on ribosomes and translation machinery.
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Affiliation(s)
- Thanh Nguyen
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Jason C. Mills
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
| | - Charles J. Cho
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
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4
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Dahan N, Bykov YS, Boydston EA, Fadel A, Gazi Z, Hochberg-Laufer H, Martenson J, Denic V, Shav-Tal Y, Weissman JS, Aviram N, Zalckvar E, Schuldiner M. Peroxisome function relies on organelle-associated mRNA translation. SCIENCE ADVANCES 2022; 8:eabk2141. [PMID: 35020435 PMCID: PMC8754406 DOI: 10.1126/sciadv.abk2141] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/18/2021] [Indexed: 05/26/2023]
Abstract
Crucial metabolic functions of peroxisomes rely on a variety of peroxisomal membrane proteins (PMPs). While mRNA transcripts of PMPs were shown to be colocalized with peroxisomes, the process by which PMPs efficiently couple translation with targeting to the peroxisomal membrane remained elusive. Here, we combine quantitative electron microscopy with proximity-specific ribosome profiling and reveal that translation of specific PMPs occurs on the surface of peroxisomes in the yeast Saccharomyces cerevisiae. This places peroxisomes alongside chloroplasts, mitochondria, and the endoplasmic reticulum as organelles that use localized translation for ensuring correct insertion of hydrophobic proteins into their membranes. Moreover, the correct targeting of these transcripts to peroxisomes is crucial for peroxisomal and cellular function, emphasizing the importance of localized translation for cellular physiology.
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Affiliation(s)
- Noa Dahan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yury S. Bykov
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Elizabeth A. Boydston
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, California Institute for Quantitative Biosciences, Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Amir Fadel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Zohar Gazi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hodaya Hochberg-Laufer
- The Mina and Everard Goodman Faculty of Life Sciences, The Bar-Ilan Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat Gan 5290002, Israel
| | - James Martenson
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford St., Cambridge, MA 02138, USA
| | - Vlad Denic
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford St., Cambridge, MA 02138, USA
| | - Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences, The Bar-Ilan Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Jonathan S. Weissman
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, California Institute for Quantitative Biosciences, Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Naama Aviram
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
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5
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Tocchini C, Rohner M, Guerard L, Ray P, Von Stetina SE, Mango SE. Translation-dependent mRNA localization to Caenorhabditis elegans adherens junctions. Development 2021; 148:273751. [PMID: 34846063 PMCID: PMC8722394 DOI: 10.1242/dev.200027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/08/2021] [Indexed: 11/27/2022]
Abstract
mRNA localization is an evolutionarily widespread phenomenon that can facilitate subcellular protein targeting. Extensive work has focused on mRNA targeting through ‘zip-codes’ within untranslated regions (UTRs), whereas much less is known about translation-dependent cues. Here, we examine mRNA localization in Caenorhabditis elegans embryonic epithelia. From an smFISH-based survey, we identified mRNAs associated with the cell membrane or cortex, and with apical junctions in a stage- and cell type-specific manner. Mutational analyses for one of these transcripts, dlg-1/discs large, revealed that it relied on a translation-dependent process and did not require its 5′ or 3′ UTRs. We suggest a model in which dlg-1 transcripts are co-translationally localized with the nascent protein: first the translating complex goes to the cell membrane using sequences located at the C-terminal/3′ end, and then apically using N-terminal/5′ sequences. These studies identify a translation-based process for mRNA localization within developing epithelia and determine the necessary cis-acting sequences for dlg-1 mRNA targeting. Summary: An smFISH-based survey identifies a subset of mRNAs encoding junctional components that localize at or in proximity to the adherens junction through a translation-dependent mechanism.
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Affiliation(s)
| | - Michèle Rohner
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | | | - Poulomi Ray
- Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Susan E Mango
- Biozentrum, University of Basel, 4056 Basel, Switzerland
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6
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Weber R, Chung MY, Keskeny C, Zinnall U, Landthaler M, Valkov E, Izaurralde E, Igreja C. 4EHP and GIGYF1/2 Mediate Translation-Coupled Messenger RNA Decay. Cell Rep 2021; 33:108262. [PMID: 33053355 DOI: 10.1016/j.celrep.2020.108262] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 08/26/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Current models of mRNA turnover indicate that cytoplasmic degradation is coupled with translation. However, our understanding of the molecular events that coordinate ribosome transit with the mRNA decay machinery is still limited. Here, we show that 4EHP-GIGYF1/2 complexes trigger co-translational mRNA decay. Human cells lacking these proteins accumulate mRNAs with prominent ribosome pausing. They include, among others, transcripts encoding secretory and membrane-bound proteins or tubulin subunits. In addition, 4EHP-GIGYF1/2 complexes fail to reduce mRNA levels in the absence of ribosome stalling or upon disruption of their interaction with the cap structure, DDX6, and ZNF598. We further find that co-translational binding of GIGYF1/2 to the mRNA marks transcripts with perturbed elongation to decay. Our studies reveal how a repressor complex linked to neurological disorders minimizes the protein output of a subset of mRNAs.
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Affiliation(s)
- Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Min-Yi Chung
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Csilla Keskeny
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Ulrike Zinnall
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115 Berlin, Germany; IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115 Berlin, Germany; IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany.
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7
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Loh D, Reiter RJ. Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders. Antioxidants (Basel) 2021; 10:1483. [PMID: 34573116 PMCID: PMC8465482 DOI: 10.3390/antiox10091483] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX 78229, USA
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8
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Ye F, Wang X, Tu S, Zeng L, Deng X, Luo W, Zhang Z. The effects of NCBP3 on METTL3-mediated m6A RNA methylation to enhance translation process in hypoxic cardiomyocytes. J Cell Mol Med 2021; 25:8920-8928. [PMID: 34382339 PMCID: PMC8435433 DOI: 10.1111/jcmm.16852] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/22/2021] [Accepted: 07/31/2021] [Indexed: 12/02/2022] Open
Abstract
Hypoxia as a crucial pathogenesis factor usually results in huge harmful effects on cardiac injury and dysfunction. Our previous study has uncovered the global transcriptome and translatome profiles of cardiomyocytes in vitro and in vivo to response to hypoxia by RNA sequencing and ribosome profiling sequencing. We observe a series of differential expressed genes between transcription and translation, which may be attributed to the hypoxia‐specific binding affinity of nuclear cap‐binding subunit 3 (NCBP3) at 5' untranslation region of target genes. Although we observe that NCBP3 can facilitate translational process in myocardium under hypoxia stress, the underlying molecular mechanism of NCBP3 for gene translation modulation remains unclear. In this study, we performed NCBP3 immunoprecipitation for mass spectrum and found that METTL3 and eIF4A2 particularly interacted with NCBP3 in hypoxic rat H9C2 cardiomyocytes. Furthermore, we observed that METTL3‐mediated N6‐methyladenosine (m6A) methylation was elevated in hypoxia, but compromised by NCBP3 or METTL3 knockdown. Finally, we also demonstrated that NCBP3/METTL3/eIF4A2 regulatory axis plays a specific role in cardiomyocytes undergoing hypoxic stress. Taken together, we unmasked NCBP3, a novel hypoxia‐specific response protein functions as a scaffold to coordinate METTL3 and eIF4A2 for enhancing gene translation by m6A RNA methylation in cardiomyocytes upon hypoxic stress.
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Affiliation(s)
- Fei Ye
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xiaoyan Wang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - San Tu
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Lixiong Zeng
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xu Deng
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Wenzhi Luo
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Zhihui Zhang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
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9
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Abstract
Biomolecular condensates concentrate molecules to facilitate basic biochemical processes, including transcription and DNA replication. While liquid-like condensates have been ascribed various functions, solid-like condensates are generally thought of as amorphous sites of protein storage. Here, we show that solid-like amyloid bodies coordinate local nuclear protein synthesis (LNPS) during stress. On stimulus, translationally active ribosomes accumulate along fiber-like assemblies that characterize amyloid bodies. Mass spectrometry analysis identified regulatory ribosomal proteins and translation factors that relocalize from the cytoplasm to amyloid bodies to sustain LNPS. These amyloidogenic compartments are enriched in newly transcribed messenger RNA by Heat Shock Factor 1 (HSF1). Depletion of stress-induced ribosomal intergenic spacer noncoding RNA (rIGSRNA) that constructs amyloid bodies prevents recruitment of the nuclear protein synthesis machinery, abolishes LNPS, and impairs the nuclear HSF1 response. We propose that amyloid bodies support local nuclear translation during stress and that solid-like condensates can facilitate complex biochemical reactions as their liquid counterparts can.
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10
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Bhadra P, Schorr S, Lerner M, Nguyen D, Dudek J, Förster F, Helms V, Lang S, Zimmermann R. Quantitative Proteomics and Differential Protein Abundance Analysis after Depletion of Putative mRNA Receptors in the ER Membrane of Human Cells Identifies Novel Aspects of mRNA Targeting to the ER. Molecules 2021; 26:3591. [PMID: 34208277 PMCID: PMC8230838 DOI: 10.3390/molecules26123591] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/28/2022] Open
Abstract
In human cells, one-third of all polypeptides enter the secretory pathway at the endoplasmic reticulum (ER). The specificity and efficiency of this process are guaranteed by targeting of mRNAs and/or polypeptides to the ER membrane. Cytosolic SRP and its receptor in the ER membrane facilitate the cotranslational targeting of most ribosome-nascent precursor polypeptide chain (RNC) complexes together with the respective mRNAs to the Sec61 complex in the ER membrane. Alternatively, fully synthesized precursor polypeptides are targeted to the ER membrane post-translationally by either the TRC, SND, or PEX19/3 pathway. Furthermore, there is targeting of mRNAs to the ER membrane, which does not involve SRP but involves mRNA- or RNC-binding proteins on the ER surface, such as RRBP1 or KTN1. Traditionally, the targeting reactions were studied in cell-free or cellular assays, which focus on a single precursor polypeptide and allow the conclusion of whether a certain precursor can use a certain pathway. Recently, cellular approaches such as proximity-based ribosome profiling or quantitative proteomics were employed to address the question of which precursors use certain pathways under physiological conditions. Here, we combined siRNA-mediated depletion of putative mRNA receptors in HeLa cells with label-free quantitative proteomics and differential protein abundance analysis to characterize RRBP1- or KTN1-involving precursors and to identify possible genetic interactions between the various targeting pathways. Furthermore, we discuss the possible implications on the so-called TIGER domains and critically discuss the pros and cons of this experimental approach.
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Affiliation(s)
- Pratiti Bhadra
- Center for Bioinformatics, Saarland Informatics Campus, Saarland University, 66041 Saarbrücken, Germany; (P.B.); (D.N.); (V.H.)
| | - Stefan Schorr
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (S.S.); (M.L.); (J.D.); (S.L.)
| | - Monika Lerner
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (S.S.); (M.L.); (J.D.); (S.L.)
| | - Duy Nguyen
- Center for Bioinformatics, Saarland Informatics Campus, Saarland University, 66041 Saarbrücken, Germany; (P.B.); (D.N.); (V.H.)
| | - Johanna Dudek
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (S.S.); (M.L.); (J.D.); (S.L.)
| | - Friedrich Förster
- Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands;
| | - Volkhard Helms
- Center for Bioinformatics, Saarland Informatics Campus, Saarland University, 66041 Saarbrücken, Germany; (P.B.); (D.N.); (V.H.)
| | - Sven Lang
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (S.S.); (M.L.); (J.D.); (S.L.)
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (S.S.); (M.L.); (J.D.); (S.L.)
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11
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Natua S, Dhamdhere SG, Mutnuru SA, Shukla S. Interplay within tumor microenvironment orchestrates neoplastic RNA metabolism and transcriptome diversity. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1676. [PMID: 34109748 DOI: 10.1002/wrna.1676] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/03/2021] [Accepted: 05/25/2021] [Indexed: 12/11/2022]
Abstract
The heterogeneous population of cancer cells within a tumor mass interacts intricately with the multifaceted aspects of the surrounding microenvironment. The reciprocal crosstalk between cancer cells and the tumor microenvironment (TME) shapes the cancer pathophysiome in a way that renders it uniquely suited for immune tolerance, angiogenesis, metastasis, and therapy resistance. This dynamic interaction involves a dramatic reconstruction of the transcriptomic landscape of tumors by altering the synthesis, modifications, stability, and processing of gene readouts. In this review, we categorically evaluate the influence of TME components, encompassing a myriad of resident and infiltrating cells, signaling molecules, extracellular vesicles, extracellular matrix, and blood vessels, in orchestrating the cancer-specific metabolism and diversity of both mRNA and noncoding RNA, including micro RNA, long noncoding RNA, circular RNA among others. We also highlight the transcriptomic adaptations in response to the physicochemical idiosyncrasies of TME, which include tumor hypoxia, extracellular acidosis, and osmotic stress. Finally, we provide a nuanced analysis of existing and prospective therapeutics targeting TME to ameliorate cancer-associated RNA metabolism, consequently thwarting the cancer progression. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Turnover and Surveillance > Regulation of RNA Stability RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Subhashis Natua
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Shruti Ganesh Dhamdhere
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Srinivas Abhishek Mutnuru
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
| | - Sanjeev Shukla
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh, 462066, India
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12
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Yan Z, Lécuyer E, Blanchette M. Prediction of mRNA subcellular localization using deep recurrent neural networks. Bioinformatics 2020; 35:i333-i342. [PMID: 31510698 PMCID: PMC6612824 DOI: 10.1093/bioinformatics/btz337] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
MOTIVATION Messenger RNA subcellular localization mechanisms play a crucial role in post-transcriptional gene regulation. This trafficking is mediated by trans-acting RNA-binding proteins interacting with cis-regulatory elements called zipcodes. While new sequencing-based technologies allow the high-throughput identification of RNAs localized to specific subcellular compartments, the precise mechanisms at play, and their dependency on specific sequence elements, remain poorly understood. RESULTS We introduce RNATracker, a novel deep neural network built to predict, from their sequence alone, the distributions of mRNA transcripts over a predefined set of subcellular compartments. RNATracker integrates several state-of-the-art deep learning techniques (e.g. CNN, LSTM and attention layers) and can make use of both sequence and secondary structure information. We report on a variety of evaluations showing RNATracker's strong predictive power, which is significantly superior to a variety of baseline predictors. Despite its complexity, several aspects of the model can be isolated to yield valuable, testable mechanistic hypotheses, and to locate candidate zipcode sequences within transcripts. AVAILABILITY AND IMPLEMENTATION Code and data can be accessed at https://www.github.com/HarveyYan/RNATracker. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Zichao Yan
- School of Computer Science, McGill University, Montreal, QC, Canada
| | - Eric Lécuyer
- Department of Biochemistry, University of Montreal, Montreal, QC, Canada.,Institut de Recherches Clinique de Montréal (IRCM), Montreal, QC, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada
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13
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Lee P, Chandel NS, Simon MC. Cellular adaptation to hypoxia through hypoxia inducible factors and beyond. Nat Rev Mol Cell Biol 2020; 21:268-283. [PMID: 32144406 PMCID: PMC7222024 DOI: 10.1038/s41580-020-0227-y] [Citation(s) in RCA: 566] [Impact Index Per Article: 141.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Molecular oxygen (O2) sustains intracellular bioenergetics and is consumed by numerous biochemical reactions, making it essential for most species on Earth. Accordingly, decreased oxygen concentration (hypoxia) is a major stressor that generally subverts life of aerobic species and is a prominent feature of pathological states encountered in bacterial infection, inflammation, wounds, cardiovascular defects and cancer. Therefore, key adaptive mechanisms to cope with hypoxia have evolved in mammals. Systemically, these adaptations include increased ventilation, cardiac output, blood vessel growth and circulating red blood cell numbers. On a cellular level, ATP-consuming reactions are suppressed, and metabolism is altered until oxygen homeostasis is restored. A critical question is how mammalian cells sense oxygen levels to coordinate diverse biological outputs during hypoxia. The best-studied mechanism of response to hypoxia involves hypoxia inducible factors (HIFs), which are stabilized by low oxygen availability and control the expression of a multitude of genes, including those involved in cell survival, angiogenesis, glycolysis and invasion/metastasis. Importantly, changes in oxygen can also be sensed via other stress pathways as well as changes in metabolite levels and the generation of reactive oxygen species by mitochondria. Collectively, this leads to cellular adaptations of protein synthesis, energy metabolism, mitochondrial respiration, lipid and carbon metabolism as well as nutrient acquisition. These mechanisms are integral inputs into fine-tuning the responses to hypoxic stress.
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Affiliation(s)
- Pearl Lee
- Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
| | - Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | - M Celeste Simon
- Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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14
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Chaudhuri A, Das S, Das B. Localization elements and zip codes in the intracellular transport and localization of messenger RNAs in Saccharomyces cerevisiae. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1591. [PMID: 32101377 DOI: 10.1002/wrna.1591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/13/2022]
Abstract
Intracellular trafficking and localization of mRNAs provide a mechanism of regulation of expression of genes with excellent spatial control. mRNA localization followed by localized translation appears to be a mechanism of targeted protein sorting to a specific cell-compartment, which is linked to the establishment of cell polarity, cell asymmetry, embryonic axis determination, and neuronal plasticity in metazoans. However, the complexity of the mechanism and the components of mRNA localization in higher organisms prompted the use of the unicellular organism Saccharomyces cerevisiae as a simplified model organism to study this vital process. Current knowledge indicates that a variety of mRNAs are asymmetrically and selectively localized to the tip of the bud of the daughter cells, to the vicinity of endoplasmic reticulum, mitochondria, and nucleus in this organism, which are connected to diverse cellular processes. Interestingly, specific cis-acting RNA localization elements (LEs) or RNA zip codes play a crucial role in the localization and trafficking of these localized mRNAs by providing critical binding sites for the specific RNA-binding proteins (RBPs). In this review, we present a comprehensive account of mRNA localization in S. cerevisiae, various types of localization elements influencing the mRNA localization, and the RBPs, which bind to these LEs to implement a number of vital physiological processes. Finally, we emphasize the significance of this process by highlighting their connection to several neuropathological disorders and cancers. This article is categorized under: RNA Export and Localization > RNA Localization.
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Affiliation(s)
- Anusha Chaudhuri
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Subhadeep Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
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15
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Chou HL, Tian L, Fukuda M, Kumamaru T, Okita TW. The Role of RNA-Binding Protein OsTudor-SN in Post-Transcriptional Regulation of Seed Storage Proteins and Endosperm Development. PLANT & CELL PHYSIOLOGY 2019; 60:2193-2205. [PMID: 31198964 DOI: 10.1093/pcp/pcz113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 05/28/2019] [Indexed: 05/28/2023]
Abstract
Tudor-SN is involved in a myriad of transcriptional and post-transcriptional processes due to its modular structure consisting of 4 tandem SN domains (4SN module) and C-terminal Tsn module consisting of Tudor-partial SN domains. We had previously demonstrated that OsTudor-SN is a key player for transporting storage protein mRNAs to specific ER subdomains in developing rice endosperm. Here, we provide genetic evidence that this multifunctional RBP is required for storage protein expression, seed development and protein body formation. The rice EM1084 line, possessing a nonsynonymous mutation in the 4SN module (SN3 domain), exhibited a strong reduction in grain weight and storage protein accumulation, while a mutation in the Tudor domain (47M) or the loss of the Tsn module (43M) had much smaller effects. Immunoelectron microscopic analysis showed the presence of a new protein body type containing glutelin and prolamine inclusions in EM1084, while 43M and 47M exhibited structurally modified prolamine and glutelin protein bodies. Transcriptome analysis indicates that OsTudor-SN also functions in regulating gene expression of transcriptional factors and genes involved in developmental processes and stress responses as well as for storage proteins. Normal protein body formation, grain weight and expression of many genes were partially restored in EM1084 transgenic line complemented with wild-type OsTudor-SN gene. Overall, our study showed that OsTudor-SN possesses multiple functional properties in rice storage protein expression and seed development and that the 4SN and Tsn modules have unique roles in these processes.
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Affiliation(s)
- Hong-Li Chou
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, DC, USA
- The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Li Tian
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, DC, USA
| | - Masako Fukuda
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, DC, USA
- Plant Genetics Laboratory, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka Nishi-ku, Fukuoka, Japan
| | - Toshihiro Kumamaru
- Plant Genetics Laboratory, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka Nishi-ku, Fukuoka, Japan
| | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, DC, USA
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16
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del Castillo U, Gnazzo MM, Turpin CGS, Nguyen KCQ, Semaya E, Lam Y, de Cruz MA, Bembenek JN, Hall DH, Riggs B, Gelfand VI, Skop AR. Conserved role for Ataxin-2 in mediating endoplasmic reticulum dynamics. Traffic 2019; 20:436-447. [PMID: 30989774 PMCID: PMC6553494 DOI: 10.1111/tra.12647] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 12/17/2022]
Abstract
Ataxin-2, a conserved RNA-binding protein, is implicated in the late-onset neurodegenerative disease Spinocerebellar ataxia type-2 (SCA2). SCA2 is characterized by shrunken dendritic arbors and torpedo-like axons within the Purkinje neurons of the cerebellum. Torpedo-like axons have been described to contain displaced endoplasmic reticulum (ER) in the periphery of the cell; however, the role of Ataxin-2 in mediating ER function in SCA2 is unclear. We utilized the Caenorhabditis elegans and Drosophila homologs of Ataxin-2 (ATX-2 and DAtx2, respectively) to determine the role of Ataxin-2 in ER function and dynamics in embryos and neurons. Loss of ATX-2 and DAtx2 resulted in collapse of the ER in dividing embryonic cells and germline, and ultrastructure analysis revealed unique spherical stacks of ER in mature oocytes and fragmented and truncated ER tubules in the embryo. ATX-2 and DAtx2 reside in puncta adjacent to the ER in both C. elegans and Drosophila embryos. Lastly, depletion of DAtx2 in cultured Drosophila neurons recapitulated the shrunken dendritic arbor phenotype of SCA2. ER morphology and dynamics were severely disrupted in these neurons. Taken together, we provide evidence that Ataxin-2 plays an evolutionary conserved role in ER dynamics and morphology in C. elegans and Drosophila embryos during development and in fly neurons, suggesting a possible SCA2 disease mechanism.
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Affiliation(s)
- Urko del Castillo
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611
| | - Megan M. Gnazzo
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Christopher G. Sorensen Turpin
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996
| | - Ken C. Q. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Emily Semaya
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Yuwan Lam
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Matthew A. de Cruz
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Joshua N. Bembenek
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Blake Riggs
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Vladimir I. Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611
| | - Ahna R. Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
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Abstract
This chapter reviews our current knowledge about the spatiotemporal assembly of filoviral particles. We will follow particles from nucleocapsid entry into the cytoplasm until the nucleocapsids are enveloped at the plasma membrane. We will also highlight the currently open scientific questions surrounding filovirus assembly.
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18
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Component of splicing factor SF3b plays a key role in translational control of polyribosomes on the endoplasmic reticulum. Proc Natl Acad Sci U S A 2019; 116:9340-9349. [PMID: 31004060 DOI: 10.1073/pnas.1901742116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the morphological hallmarks of terminally differentiated secretory cells is highly proliferated membrane of the rough endoplasmic reticulum (ER), but the molecular basis for the high rate of protein biosynthesis in these cells remains poorly documented. An important aspect of ER translational control is the molecular mechanism that supports efficient use of targeted mRNAs in polyribosomes. Here, we identify an enhancement system for ER translation promoted by p180, an integral ER membrane protein we previously reported as an essential factor for the assembly of ER polyribosomes. We provide evidence that association of target mRNAs with p180 is critical for efficient translation, and that SF3b4, an RNA-binding protein in the splicing factor SF3b, functions as a cofactor for p180 at the ER and plays a key role in enhanced translation of secretory proteins. A cis-element in the 5' untranslated region of collagen and fibronectin genes is important to increase translational efficiency in the presence of p180 and SF3b4. These data demonstrate that a unique system comprising a p180-SF3b4-mRNA complex facilitates the selective assembly of polyribosomes on the ER.
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19
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Abstract
Cells respond to hypoxia by shifting cellular processes from general housekeeping functions to activating specialized hypoxia-response pathways. Oxygen plays an important role in generating ATP to maintain a productive rate of protein synthesis in normoxia. In hypoxia, the rate of the canonical protein synthesis pathway is significantly slowed and impaired due to limited ATP availability, necessitating an alternative mechanism to mediate protein synthesis and facilitate adaptation. Hypoxia adaptation is largely mediated by hypoxia-inducible factors (HIFs). While HIFs are well known for their transcriptional functions, they also play imperative roles in translation to mediate hypoxic protein synthesis. Such adaptations to hypoxia are often hyperactive in solid tumors, contributing to the expression of cancer hallmarks, including treatment resistance. The current literature on protein synthesis in hypoxia is reviewed here, inclusive of hypoxia-specific mRNA selection to translation termination. Current HIF targeting therapies are also discussed as are the opportunities involved with targeting hypoxia specific protein synthesis pathways.
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Affiliation(s)
- Nancy T Chee
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami, FL, 33136, USA
| | - Ines Lohse
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami, FL, 33136, USA
| | - Shaun P Brothers
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Avenue, Miami, FL, 33136, USA.
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20
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Sun X, Su X. Harnessing the knowledge of protein secretion for enhanced protein production in filamentous fungi. World J Microbiol Biotechnol 2019; 35:54. [PMID: 30900052 DOI: 10.1007/s11274-019-2630-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/08/2019] [Indexed: 12/19/2022]
Abstract
Filamentous fungi are important microorganisms used in industrial production of proteins and enzymes. Among these organisms, Trichoderma reesei, Aspergilli, and more recently Myceliophthora thermophile are the most widely used and promising ones which have powerful protein secretion capability. In recent years, there have been tremendous achievements in understanding the molecular mechanisms of the secretory pathways in filamentous fungi. The acquired pieces of knowledge can be harnessed to enhance protein production in filamentous fungi with assistance of state-of-the-art genetic engineering techniques.
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Affiliation(s)
- Xianhua Sun
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China
| | - Xiaoyun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China.
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21
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Hughes SC, Simmonds AJ. Drosophila mRNA Localization During Later Development: Past, Present, and Future. Front Genet 2019; 10:135. [PMID: 30899273 PMCID: PMC6416162 DOI: 10.3389/fgene.2019.00135] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/11/2019] [Indexed: 12/12/2022] Open
Abstract
Multiple mechanisms tightly regulate mRNAs during their transcription, translation, and degradation. Of these, the physical localization of mRNAs to specific cytoplasmic regions is relatively easy to detect; however, linking localization to functional regulatory roles has been more difficult to establish. Historically, Drosophila melanogaster is a highly effective model to identify localized mRNAs and has helped identify roles for this process by regulating various cell activities. The majority of the well-characterized functional roles for localizing mRNAs to sub-regions of the cytoplasm have come from the Drosophila oocyte and early syncytial embryo. At present, relatively few functional roles have been established for mRNA localization within the relatively smaller, differentiated somatic cell lineages characteristic of later development, beginning with the cellular blastoderm, and the multiple cell lineages that make up the gastrulating embryo, larva, and adult. This review is divided into three parts—the first outlines past evidence for cytoplasmic mRNA localization affecting aspects of cellular activity post-blastoderm development in Drosophila. The majority of these known examples come from highly polarized cell lineages such as differentiating neurons. The second part considers the present state of affairs where we now know that many, if not most mRNAs are localized to discrete cytoplasmic regions in one or more somatic cell lineages of cellularized embryos, larvae or adults. Assuming that the phenomenon of cytoplasmic mRNA localization represents an underlying functional activity, and correlation with the encoded proteins suggests that mRNA localization is involved in far more than neuronal differentiation. Thus, it seems highly likely that past-identified examples represent only a small fraction of localization-based mRNA regulation in somatic cells. The last part highlights recent technological advances that now provide an opportunity for probing the role of mRNA localization in Drosophila, moving beyond cataloging the diversity of localized mRNAs to a similar understanding of how localization affects mRNA activity.
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Affiliation(s)
- Sarah C Hughes
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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22
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Yang Y, Chou HL, Crofts AJ, Zhang L, Tian L, Washida H, Fukuda M, Kumamaru T, Oviedo OJ, Starkenburg SR, Okita TW. Selective sets of mRNAs localize to extracellular paramural bodies in a rice glup6 mutant. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:5045-5058. [PMID: 30102323 PMCID: PMC6189835 DOI: 10.1093/jxb/ery297] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/07/2018] [Indexed: 05/18/2023]
Abstract
The transport of rice glutelin storage proteins to the storage vacuoles requires the Rab5 GTPase and its related guanine nucleotide exchange factor (Rab5-GEF). Loss of function of these membrane vesicular trafficking factors results in the initial secretion of storage proteins and later their partial engulfment by the plasma membrane to form an extracellular paramural body (PMB), an aborted endosome complex. Here, we show that in the rice Rab5-GEF mutant glup6, glutelin RNAs are specifically mislocalized from their normal location on the cisternal endoplasmic reticulum (ER) to the protein body-ER, and are also apparently translocated to the PMBs. We substantiated the association of mRNAs with this aborted endosome complex by RNA-seq of PMBs purified by flow cytometry. Two PMB-associated groups of RNA were readily resolved: those that were specifically enriched in this aborted complex and those that were highly expressed in the cytoplasm. Examination of the PMB-enriched RNAs indicated that they were not a random sampling of the glup6 transcriptome but, instead, encompassed only a few functional mRNA classes. Although specific autophagy is also an alternative mechanism, our results support the view that RNA localization may co-opt membrane vesicular trafficking, and that many RNAs that share function or intracellular location are co-transported in developing rice seeds.
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Affiliation(s)
- Yongil Yang
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- Present address: Institute of Agriculture, The University of Tennessee, Knoxville, TN 37996, USA
| | - Hong-Li Chou
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- Present address: The Huck Institutes of the Life Sciences, Pennsylvania State University, PA 16802, USA
| | - Andrew J Crofts
- International Liberal Arts Program, Akita International University, Akita, Japan
| | - Laining Zhang
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Li Tian
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Haruhiko Washida
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- Present Address: Organic Nico Co., Ltd, North #205, Kyodai Katsura Venture Plaza, 1–36, Goryo-Ohara, Nishikyo-ku, Kyoto 615–8245, Japan
| | - Masako Fukuda
- Faculty of Agriculture, Kyushu University, Motooka Nishi-ku, Fukuoka, Japan
| | - Toshihiro Kumamaru
- Faculty of Agriculture, Kyushu University, Motooka Nishi-ku, Fukuoka, Japan
| | | | | | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- Correspondence:
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23
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Syed MI, Moorthy BT, Jenner A, Fetka I, Jansen RP. Signal sequence-independent targeting of MID2 mRNA to the endoplasmic reticulum by the yeast RNA-binding protein Khd1p. FEBS Lett 2018; 592:1870-1881. [PMID: 29772604 DOI: 10.1002/1873-3468.13098] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/26/2018] [Accepted: 05/04/2018] [Indexed: 11/10/2022]
Abstract
Localization of mRNAs depends on specific RNA-binding proteins (RBPs) and critically contributes not only to cell polarization but also to basal cell function. The yeast RBP Khd1p binds to several hundred mRNAs, the majority of which encodes secreted or membrane proteins. We demonstrate that a subfraction of Khd1p associates with artificial liposomes and endoplasmic reticulum (ER), and that Khd1p endomembrane association is partially dependent on its binding to RNA. ER targeting of at least two mRNAs, MID2 and SLG1/WSC1, requires KHD1 but is independent of their translation. Together, our results suggest interdependence of Khd1p and mRNA for their targeting to the ER and presents additional evidence for signal sequence-independent, RBP-mediated mRNA targeting.
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Affiliation(s)
- Muhammad Ibrahim Syed
- Interfaculty Institute of Biochemistry (IFIB), Eberhard Karls Universität Tübingen, Germany
| | - Balaji T Moorthy
- Interfaculty Institute of Biochemistry (IFIB), Eberhard Karls Universität Tübingen, Germany
| | - Andreas Jenner
- Interfaculty Institute of Biochemistry (IFIB), Eberhard Karls Universität Tübingen, Germany
| | - Ingrid Fetka
- Interfaculty Institute of Biochemistry (IFIB), Eberhard Karls Universität Tübingen, Germany
| | - Ralf-Peter Jansen
- Interfaculty Institute of Biochemistry (IFIB), Eberhard Karls Universität Tübingen, Germany
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24
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Namkoong S, Ho A, Woo YM, Kwak H, Lee JH. Systematic Characterization of Stress-Induced RNA Granulation. Mol Cell 2018; 70:175-187.e8. [PMID: 29576526 DOI: 10.1016/j.molcel.2018.02.025] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/06/2017] [Accepted: 02/15/2018] [Indexed: 12/20/2022]
Abstract
Upon stress, cytoplasmic mRNA is sequestered to insoluble ribonucleoprotein (RNP) granules, such as the stress granule (SG). Partially due to the belief that translationally suppressed mRNAs are recruited to SGs in bulk, stress-induced dynamic redistribution of mRNA has not been thoroughly characterized. Here, we report that endoplasmic reticulum (ER) stress targets only a small subset of translationally suppressed mRNAs into the insoluble RNP granule fraction (RG). This subset, characterized by extended length and adenylate-uridylate (AU)-rich motifs, is highly enriched with genes critical for cell survival and proliferation. This pattern of RG targeting was conserved for two other stress types, heat shock and arsenite toxicity, which induce distinct responses in the total cytoplasmic transcriptome. Nevertheless, stress-specific RG-targeting motifs, such as guanylate-cytidylate (GC)-rich motifs in heat shock, were also identified. Previously underappreciated, transcriptome profiling in the RG may contribute to understanding human diseases associated with RNP dysfunction, such as cancer and neurodegeneration.
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Affiliation(s)
- Sim Namkoong
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allison Ho
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yu Mi Woo
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Hojoong Kwak
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
| | - Jun Hee Lee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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25
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Single nucleotide polymorphisms and domain/splice variants modulate assembly and elastomeric properties of human elastin. Implications for tissue specificity and durability of elastic tissue. Biopolymers 2017; 107. [DOI: 10.1002/bip.23007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 12/03/2016] [Indexed: 12/13/2022]
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26
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Alexandrova J, Paulus C, Rudinger-Thirion J, Jossinet F, Frugier M. Elaborate uORF/IRES features control expression and localization of human glycyl-tRNA synthetase. RNA Biol 2016; 12:1301-13. [PMID: 26327585 DOI: 10.1080/15476286.2015.1086866] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The canonical activity of glycyl-tRNA synthetase (GARS) is to charge glycine onto its cognate tRNAs. However, outside translation, GARS also participates in many other functions. A single gene encodes both the cytosolic and mitochondrial forms of GARS but 2 mRNA isoforms were identified. Using immunolocalization assays, in vitro translation assays and bicistronic constructs we provide experimental evidence that one of these mRNAs tightly controls expression and localization of human GARS. An intricate regulatory domain was found in its 5'-UTR which displays a functional Internal Ribosome Entry Site and an upstream Open Reading Frame. Together, these elements hinder the synthesis of the mitochondrial GARS and target the translation of the cytosolic enzyme to ER-bound ribosomes. This finding reveals a complex picture of GARS translation and localization in mammals. In this context, we discuss how human GARS expression could influence its moonlighting activities and its involvement in diseases.
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Affiliation(s)
- Jana Alexandrova
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS ; IBMC ; 15 rue René Descartes; Strasbourg Cedex , France
| | - Caroline Paulus
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS ; IBMC ; 15 rue René Descartes; Strasbourg Cedex , France
| | - Joëlle Rudinger-Thirion
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS ; IBMC ; 15 rue René Descartes; Strasbourg Cedex , France
| | - Fabrice Jossinet
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS ; IBMC ; 15 rue René Descartes; Strasbourg Cedex , France
| | - Magali Frugier
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS ; IBMC ; 15 rue René Descartes; Strasbourg Cedex , France
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27
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Kobayashi Y, Horie M, Nakano A, Murata K, Itou T, Suzuki Y. Exaptation of Bornavirus-Like Nucleoprotein Elements in Afrotherians. PLoS Pathog 2016; 12:e1005785. [PMID: 27518265 PMCID: PMC4982594 DOI: 10.1371/journal.ppat.1005785] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/01/2016] [Indexed: 11/18/2022] Open
Abstract
Endogenous bornavirus-like nucleoprotein elements (EBLNs), the nucleotide sequence elements derived from the nucleoprotein gene of ancient bornavirus-like viruses, have been identified in many animal genomes. Here we show evidence that EBLNs encode functional proteins in their host. Some afrotherian EBLNs were observed to have been maintained for more than 83.3 million years under negative selection. Splice variants were expressed from the genomic loci of EBLNs in elephant, and some were translated into proteins. The EBLN proteins appeared to be localized to the rough endoplasmic reticulum in African elephant cells, in contrast to the nuclear localization of bornavirus N. These observations suggest that afrotherian EBLNs have acquired a novel function in their host. Interestingly, genomic sequences of the first exon and its flanking regions in these EBLN loci were homologous to those of transmembrane protein 106B (TMEM106B). The upstream region of the first exon in the EBLN loci exhibited a promoter activity, suggesting that the ability of these EBLNs to be transcribed in the host cell was gained through capturing a partial duplicate of TMEM106B. In conclusion, our results strongly support for exaptation of EBLNs to encode host proteins in afrotherians. Endogenous retroviruses are representative of endogenous viral elements (EVEs), which are known to have occasionally served as the source of evolutionary innovations of the host. Endogenous bornavirus-like nucleoprotein element (EBLN) was the first EVE identified in mammalian genomes to have been derived from a non-retroviral RNA virus. Here we show evidence that EBLNs that were integrated into afrotherian genomes more than 83.3 million years ago have gained novel protein functions associated with rough endoplasmic reticulum in afrotherians. In the amino acid sequence of EBLN proteins, negative selection appeared to have operated more strongly on hydrophilic regions than on hydrophobic regions, suggesting that EBLN proteins may interact with other molecules in their host cells. In addition, we clarified the mechanism how EBLNs have acquired an ability to be transcribed in the host cell; they captured a partial duplicate of an intrinsic gene, transmembrane protein 106B, which retained an intrinsic promoter activity. Our findings suggest that not only retroviral EVEs but also non-retroviral EVEs may have contributed to the host evolution.
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Affiliation(s)
- Yuki Kobayashi
- Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan
- * E-mail: (YK); (YS)
| | - Masayuki Horie
- Transboundary Animal Diseases Research Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Ayumi Nakano
- Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan
| | - Koichi Murata
- Department of Animal Resource Science, College of Bioresource Sciences, Nihon Universitym, Fujisawa, Kanagawa, Japan
| | - Takuya Itou
- Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan
| | - Yoshiyuki Suzuki
- Graduate School of Natural Sciences, Nagoya City University, Nagoya, Aichi, Japan
- * E-mail: (YK); (YS)
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Determinants of Genomic RNA Encapsidation in the Saccharomyces cerevisiae Long Terminal Repeat Retrotransposons Ty1 and Ty3. Viruses 2016; 8:v8070193. [PMID: 27428991 PMCID: PMC4974528 DOI: 10.3390/v8070193] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 06/21/2016] [Accepted: 06/28/2016] [Indexed: 12/12/2022] Open
Abstract
Long-terminal repeat (LTR) retrotransposons are transposable genetic elements that replicate intracellularly, and can be considered progenitors of retroviruses. Ty1 and Ty3 are the most extensively characterized LTR retrotransposons whose RNA genomes provide the template for both protein translation and genomic RNA that is packaged into virus-like particles (VLPs) and reverse transcribed. Genomic RNAs are not divided into separate pools of translated and packaged RNAs, therefore their trafficking and packaging into VLPs requires an equilibrium between competing events. In this review, we focus on Ty1 and Ty3 genomic RNA trafficking and packaging as essential steps of retrotransposon propagation. We summarize the existing knowledge on genomic RNA sequences and structures essential to these processes, the role of Gag proteins in repression of genomic RNA translation, delivery to VLP assembly sites, and encapsidation.
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Abstract
Local synthesis of proteins near their activity site has been demonstrated in many biological systems, and has diverse contributions to cellular functions. Studies in recent years have revealed that hundreds of mitochondria-destined proteins are synthesized by cytosolic ribosomes near the mitochondrial outer membrane, indicating that localized translation also occurs at this cellular locus. Furthermore, in the last year central factors that are involved in this process were identified in yeast, Drosophila, and human cells. Herein we review the experimental evidence for localized translation on the cytosolic side of the mitochondrial outer membrane; in addition, we describe the factors that are involved in this process and discuss the conservation of this mechanism among various species. We also describe the relationship between localized translation and import into the mitochondria and suggest avenues of study that look beyond cotranslational import. Finally we discuss future challenges in characterizing the mechanisms for localized translation and its physiological significance.
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Affiliation(s)
- Chen Lesnik
- a Department of Biology ; Technion - Israel Institute of Technology ; Haifa , Israel
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30
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Zhang Y, Stefanovic B. LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression. Int J Mol Sci 2016; 17:419. [PMID: 27011170 PMCID: PMC4813270 DOI: 10.3390/ijms17030419] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 01/15/2023] Open
Abstract
Type I collagen is the most abundant structural protein in all vertebrates, but its constitutive rate of synthesis is low due to long half-life of the protein (60-70 days). However, several hundred fold increased production of type I collagen is often seen in reparative or reactive fibrosis. The mechanism which is responsible for this dramatic upregulation is complex, including multiple levels of regulation. However, posttranscriptional regulation evidently plays a predominant role. Posttranscriptional regulation comprises processing, transport, stabilization and translation of mRNAs and is executed by RNA binding proteins. There are about 800 RNA binding proteins, but only one, La ribonucleoprotein domain family member 6 (LARP6), is specifically involved in type I collagen regulation. In the 5'untranslated region (5'UTR) of mRNAs encoding for type I and type III collagens there is an evolutionally conserved stem-loop (SL) structure; this structure is not found in any other mRNA, including any other collagen mRNA. LARP6 binds to the 5'SL in sequence specific manner to regulate stability of collagen mRNAs and their translatability. Here, we will review current understanding of how is LARP6 involved in posttranscriptional regulation of collagen mRNAs. We will also discuss how other proteins recruited by LARP6, including nonmuscle myosin, vimentin, serine threonine kinase receptor associated protein (STRAP), 25 kD FK506 binding protein (FKBP25) and RNA helicase A (RHA), contribute to this process.
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Affiliation(s)
- Yujie Zhang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
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31
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Bauer NC, Doetsch PW, Corbett AH. Mechanisms Regulating Protein Localization. Traffic 2015; 16:1039-61. [PMID: 26172624 DOI: 10.1111/tra.12310] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 12/23/2022]
Abstract
Cellular functions are dictated by protein content and activity. There are numerous strategies to regulate proteins varying from modulating gene expression to post-translational modifications. One commonly used mode of regulation in eukaryotes is targeted localization. By specifically redirecting the localization of a pool of existing protein, cells can achieve rapid changes in local protein function. Eukaryotic cells have evolved elegant targeting pathways to direct proteins to the appropriate cellular location or locations. Here, we provide a general overview of these localization pathways, with a focus on nuclear and mitochondrial transport, and present a survey of the evolutionarily conserved regulatory strategies identified thus far. We end with a description of several specific examples of proteins that exploit localization as an important mode of regulation.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Current address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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32
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Abstract
Intracellular logistics are essential for delivery of newly synthesized material during polar growth of fungal hyphae. Proteins and lipids are actively transported throughout the cell by motor-dependent movement of small vesicles or larger units such as endosomes and the endoplasmic reticulum. A remarkably tight link is emerging between active membrane trafficking and mRNA transport, a process that determines the precise subcellular localization of translation products within the cell. Here, we report on recent insights into the mechanism and biological role of these intricate cotransport processes in fungal models such as Saccharomyces cerevisiae, Candida albicans, and Ustilago maydis. In the latter, we focus on the new finding of endosomal mRNA transport and its implications for protein targeting, complex assembly, and septin biology.
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Affiliation(s)
- Carl Haag
- Cluster of Excellence on Plant Sciences, Institute for Microbiology, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany; , ,
| | - Benedikt Steuten
- Cluster of Excellence on Plant Sciences, Institute for Microbiology, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany; , ,
| | - Michael Feldbrügge
- Cluster of Excellence on Plant Sciences, Institute for Microbiology, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany; , ,
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33
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Singer-Krüger B, Jansen RP. Here, there, everywhere. mRNA localization in budding yeast. RNA Biol 2014; 11:1031-9. [PMID: 25482891 DOI: 10.4161/rna.29945] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
mRNA localization and localized translation is a common mechanism that contributes to cell polarity and cellular asymmetry. In metazoan, mRNA transport participates in embryonic axis determination and neuronal plasticity. Since the mRNA localization process and its molecular machinery are rather complex in higher eukaryotes, the unicellular yeast Saccharomyces cerevisiae has become an attractive model to study mRNA localization. Although the focus has so far been on the mechanism of ASH1 mRNA transport, it has become evident that mRNA localization also assists in protein sorting to organelles, as well as in polarity establishment and maintenance. A diversity of different pathways has been identified that targets mRNA to their destination site, ranging from motor protein-dependent trafficking of translationally silenced mRNAs to co-translational targeting, in which mRNAs hitch-hike to organelles on ribosomes during nascent polypeptide chain elongation. The presence of these diverse pathways in yeast allows a systemic analysis of the contribution of mRNA localization to the physiology of a cell.
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Affiliation(s)
- Birgit Singer-Krüger
- a Interfaculty Institute of Biochemistry ; University of Tübingen ; Tübingen , Germany
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34
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Niedner A, Edelmann FT, Niessing D. Of social molecules: The interactive assembly of ASH1 mRNA-transport complexes in yeast. RNA Biol 2014; 11:998-1009. [PMID: 25482892 PMCID: PMC4615550 DOI: 10.4161/rna.29946] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Asymmetric, motor-protein dependent transport of mRNAs and subsequent localized translation is an important mechanism of gene regulation. Due to the high complexity of such motile particles, our mechanistic understanding of mRNA localization is limited. Over the last two decades, ASH1 mRNA localization in budding yeast has served as comparably simple and accessible model system. Recent advances have helped to draw an increasingly clear picture on the molecular mechanisms governing ASH1 mRNA localization from its co-transcriptional birth to its delivery at the site of destination. These new insights help to better understand the requirement of initial nuclear mRNPs, the molecular basis of specific mRNA-cargo recognition via cis-acting RNA elements, the different stages of RNP biogenesis and reorganization, as well as activation of the motile activity upon cargo binding. We discuss these aspects in context of published findings from other model organisms.
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Affiliation(s)
- Annika Niedner
- a Institute of Structural Biology; Helmholtz Zentrum München - German Center for Environmental Health ; Neuherberg , Germany
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35
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Wang H, Stefanovic B. Role of LARP6 and nonmuscle myosin in partitioning of collagen mRNAs to the ER membrane. PLoS One 2014; 9:e108870. [PMID: 25271881 PMCID: PMC4182744 DOI: 10.1371/journal.pone.0108870] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/01/2014] [Indexed: 02/07/2023] Open
Abstract
Type I collagen is extracellular matrix protein composed of two α1(I) and one α2(I) polypeptides that fold into triple helix. Collagen polypeptides are translated in coordination to synchronize the rate of triple helix folding to the rate of posttranslational modifications of individual polypeptides. This is especially important in conditions of high collagen production, like fibrosis. It has been assumed that collagen mRNAs are targeted to the membrane of the endoplasmic reticulum (ER) after translation of the signal peptide and by signal peptide recognition particle (SRP). Here we show that collagen mRNAs associate with the ER membrane even when translation is inhibited. Knock down of LARP6, an RNA binding protein which binds 5' stem-loop of collagen mRNAs, releases a small amount of collagen mRNAs from the membrane. Depolimerization of nonmuscle myosin filaments has a similar, but stronger effect. In the absence of LARP6 or nonmuscle myosin filaments collagen polypeptides become hypermodified, are poorly secreted and accumulate in the cytosol. This indicates lack of coordination of their synthesis and retro-translocation due to hypermodifications and misfolding. Depolimerization of nonmuscle myosin does not alter the secretory pathway through ER and Golgi, suggesting that the role of nonmuscle myosin is primarily to partition collagen mRNAs to the ER membrane. We postulate that collagen mRNAs directly partition to the ER membrane prior to synthesis of the signal peptide and that LARP6 and nonmuscle myosin filaments mediate this process. This allows coordinated initiation of translation on the membrane bound collagen α1(I) and α2(I) mRNAs, a necessary step for proper synthesis of type I collagen.
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Affiliation(s)
- Hao Wang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
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36
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Liao G, Mingle L, Van De Water L, Liu G. Control of cell migration through mRNA localization and local translation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:1-15. [PMID: 25264217 DOI: 10.1002/wrna.1265] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/13/2014] [Accepted: 07/31/2014] [Indexed: 02/06/2023]
Abstract
Cell migration plays an important role in many normal and pathological functions such as development, wound healing, immune defense, and tumor metastasis. Polarized migrating cells exhibit asymmetric distribution of many cytoskeletal proteins, which is believed to be critical for establishing and maintaining cell polarity and directional cell migration. To target these proteins to the site of function, cells use a variety of mechanisms such as protein transport and messenger RNA (mRNA) localization-mediated local protein synthesis. In contrast to the former which is intensively investigated and relatively well understood, the latter has been understudied and relatively poorly understood. However, recent advances in the study of mRNA localization and local translation have demonstrated that mRNA localization and local translation are specific and effective ways for protein localization and are crucial for embryo development, neuronal function, and many other cellular processes. There are excellent reviews on mRNA localization, transport, and translation during development and other cellular processes. This review will focus on mRNA localization-mediated local protein biogenesis and its impact on somatic cell migration.
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Affiliation(s)
- Guoning Liao
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, NY, USA
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37
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mRNA transport meets membrane traffic. Trends Genet 2014; 30:408-17. [DOI: 10.1016/j.tig.2014.07.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/09/2014] [Accepted: 07/09/2014] [Indexed: 02/07/2023]
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38
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Differential targeting of VDAC3 mRNA isoforms influences mitochondria morphology. Proc Natl Acad Sci U S A 2014; 111:8991-6. [PMID: 24889622 DOI: 10.1073/pnas.1402588111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Intracellular targeting of mRNAs has recently emerged as a prevalent mechanism to control protein localization. For mitochondria, a cotranslational model of protein import is now proposed in parallel to the conventional posttranslational model, and mitochondrial targeting of mRNAs has been demonstrated in various organisms. Voltage-dependent anion channels (VDACs) are the most abundant proteins in the outer mitochondrial membrane and the major transport pathway for numerous metabolites. Four nucleus-encoded VDACs have been identified in Arabidopsis thaliana. Alternative cleavage and polyadenylation generate two VDAC3 mRNA isoforms differing by their 3' UTR. By using quantitative RT-PCR and in vivo mRNA visualization approaches, the two mRNA variants were shown differentially associated with mitochondria. The longest mRNA presents a 3' extension named alternative UTR (aUTR) that is necessary and sufficient to target VDAC3 mRNA to the mitochondrial surface. Moreover, aUTR is sufficient for the mitochondrial targeting of a reporter transcript, and can be used as a tool to target an unrelated mRNA to the mitochondrial surface. Finally, VDAC3-aUTR mRNA variant impacts mitochondria morphology and size, demonstrating the role of mRNA targeting in mitochondria biogenesis.
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39
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Denks K, Vogt A, Sachelaru I, Petriman NA, Kudva R, Koch HG. The Sec translocon mediated protein transport in prokaryotes and eukaryotes. Mol Membr Biol 2014; 31:58-84. [DOI: 10.3109/09687688.2014.907455] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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40
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Abstract
Cells use messenger RNAs (mRNAs) to ensure the accurate dissemination of genetic information encoded by DNA. Given that mRNAs largely direct the synthesis of a critical effector of cellular phenotype, i.e., proteins, tight regulation of both the quality and quantity of mRNA is a prerequisite for effective cellular homeostasis. Here, we review nonsense-mediated mRNA decay (NMD), which is the best-characterized posttranscriptional quality control mechanism that cells have evolved in their cytoplasm to ensure transcriptome fidelity. We use protein quality control as a conceptual framework to organize what is known about NMD, highlighting overarching similarities between these two polymer quality control pathways, where the protein quality control and NMD pathways intersect, and how protein quality control can suggest new avenues for research into mRNA quality control.
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Affiliation(s)
- Maximilian Wei-Lin Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642;
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41
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RNA-binding proteins in neurological diseases. SCIENCE CHINA-LIFE SCIENCES 2014; 57:432-44. [DOI: 10.1007/s11427-014-4647-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/25/2014] [Indexed: 12/12/2022]
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42
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Doh JH, Lutz S, Curcio MJ. Co-translational localization of an LTR-retrotransposon RNA to the endoplasmic reticulum nucleates virus-like particle assembly sites. PLoS Genet 2014; 10:e1004219. [PMID: 24603646 PMCID: PMC3945221 DOI: 10.1371/journal.pgen.1004219] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/18/2014] [Indexed: 11/18/2022] Open
Abstract
The transcript of retrovirus-like transposons functions as an mRNA for synthesis of capsid and replication proteins and as the genomic RNA of virus-like particles (VLPs), wherein the genome is replicated. Retrotransposon RNA and proteins coalesce in a cytoplasmic focus, or retrosome, to initiate VLP assembly, but it is not known how the retrosome is nucleated. We determined how the RNA and Gag protein of the Saccharomyces cerevisiae Ty1 retrotransposon are directed to the retrosome. We found that Ty1 RNA is translated in association with signal recognition particle (SRP), a universally conserved chaperone that binds specific ribosome-nascent chain (RNC) complexes and targets the nascent peptide to the endoplasmic reticulum (ER). Gag is translocated to the ER lumen; yet, it is also found in the cytoplasm, associated with SRP-RNC complexes. In the absence of ER translocation, Gag is synthesized but rapidly degraded, and Ty1 RNA does not coalesce in retrosomes. These findings suggest that Gag adopts a stable conformation in the ER lumen, is retrotranslocated to the cytoplasm, binds to Ty1 RNA on SRP-RNC complexes and multimerizes to nucleate retrosomes. Consistent with this model, we show that slowing the rate of co-translational ER translocation by limiting SRP increases the prevalence of retrosomes, while suppressing the translocation defect of srp hypomorphs by slowing translational elongation rapidly decreases retrosome formation. Thus, retrosomes are dynamic foci of Ty1 RNA-RNC complexes whose formation is modulated by the rate of co-translational ER translocation. Together, these findings suggest that translating Ty1 mRNA and the genomic RNA of VLPs originate in a single pool and moreover, that co-translational localization of Ty1 RNA nucleates the presumptive VLP assembly site. The separation of nascent Gag from its RNA template by transit through the ER allows Gag to bind translating Ty1 RNA without displaying a cis-preference for its encoding RNA. Retrotransposons are mobile elements that have invaded the genomes of organisms from bacteria to humans. Facilitated by host co-factors, retrotransposon proteins copy their RNA genomes into DNA that integrates into the host genome, causing mutations and genome instability. The yeast Ty1 element belongs to a family of retrotransposons that are related to infectious retroviruses. Ty1 RNA and its coat protein, Gag, assemble into virus-like particles, wherein the RNA is copied into DNA. It was not previously known how Ty1 RNA and Gag are concentrated in a specific cellular location to initiate the assembly of virus-like particles. In this study, we show that Ty1 RNA is brought to the presumptive assembly site during translation by the protein chaperone, signal recognition particle. As Ty1 RNA is translated, the nascent Gag polypeptide enters the lumen of the endoplasmic reticulum, where Gag adopts a stable conformation before returning to the cytoplasm to bind to translating Ty1 RNA. An interaction between Gag molecules bound to translating Ty1 RNA results in the nucleation of the virus-like particle assembly site. Our findings identify new host co-factors in retrotransposon mobility and suggest potential approaches to controlling retrotransposon-associated genome instability in aging and cancer.
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Affiliation(s)
- Jung H. Doh
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - Sheila Lutz
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - M. Joan Curcio
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, United States of America
- * E-mail:
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43
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Genz C, Fundakowski J, Hermesh O, Schmid M, Jansen RP. Association of the yeast RNA-binding protein She2p with the tubular endoplasmic reticulum depends on membrane curvature. J Biol Chem 2013; 288:32384-32393. [PMID: 24056370 DOI: 10.1074/jbc.m113.486431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Localization of mRNAs contributes to the generation and maintenance of cellular asymmetry in a wide range of organisms. In Saccharomyces cerevisiae, the so-called locasome complex with its core components Myo4p, She2p, and She3p localizes more than 30 mRNAs to the yeast bud tip. A significant fraction of these mRNAs encodes membrane or secreted proteins. Their localization requires, besides the locasome, a functional segregation apparatus of the cortical endoplasmic reticulum (ER), including the machinery that is involved in the movement of ER tubules into the bud. Colocalization of RNA-containing particles with these tubules suggests a coordinated transport of localized mRNAs and the cortical ER to the bud. Association of localized mRNAs to the ER requires the presence of the locasome component She2p. Here we report that She2p is not only an RNA-binding protein but can specifically bind to ER-derived membranes in a membrane curvature-dependent manner in vitro. Although it does not contain any known curvature recognizing motifs, the protein shows a binding preference for liposomes with a diameter resembling that of yeast ER tubules. In addition, membrane binding depends on tetramerization of She2p. In an in vivo membrane-tethering assay, She2p can target a viral peptide GFP fusion protein to the cortical ER, indicating that a fraction of She2p associates with the ER in vivo. Combining RNA- and membrane-binding features makes She2p an ideal coordinator of ER tubule and mRNA cotransport.
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Affiliation(s)
- Christian Genz
- From the Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, 72076 Tübingen, Germany
| | - Julia Fundakowski
- From the Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, 72076 Tübingen, Germany
| | - Orit Hermesh
- From the Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, 72076 Tübingen, Germany
| | - Maria Schmid
- the Gene Center, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Ralf-Peter Jansen
- From the Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, 72076 Tübingen, Germany.
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