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Zare A, Salehi S, Bader J, Schneider C, Fischer U, Veh A, Arampatzi P, Mann M, Briese M, Sendtner M. hnRNP R promotes O-GlcNAcylation of eIF4G and facilitates axonal protein synthesis. Nat Commun 2024; 15:7430. [PMID: 39198412 PMCID: PMC11358521 DOI: 10.1038/s41467-024-51678-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 08/12/2024] [Indexed: 09/01/2024] Open
Abstract
Motoneurons critically depend on precise spatial and temporal control of translation for axon growth and the establishment and maintenance of neuromuscular connections. While defects in local translation have been implicated in the pathogenesis of motoneuron disorders, little is known about the mechanisms regulating axonal protein synthesis. Here, we report that motoneurons derived from Hnrnpr knockout mice show reduced axon growth accompanied by lowered synthesis of cytoskeletal and synaptic components in axons. Mutant mice display denervated neuromuscular junctions and impaired motor behavior. In axons, hnRNP R is a component of translation initiation complexes and, through interaction with O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (Ogt), modulates O-GlcNAcylation of eIF4G. Restoring axonal O-GlcNAc levels rescued local protein synthesis and axon growth defects of hnRNP R knockout motoneurons. Together, these findings demonstrate a function of hnRNP R in controlling the local production of key factors required for axon growth and formation of neuromuscular innervations.
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Affiliation(s)
- Abdolhossein Zare
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Saeede Salehi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Jakob Bader
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Cornelius Schneider
- Department of Biochemistry, Theodor Boveri Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Utz Fischer
- Department of Biochemistry, Theodor Boveri Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Alexander Veh
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | | | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
- NNF Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
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2
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Tarannum R, Mun G, Quddos F, Swanger SA, Steward O, Farris S. Dendritically localized RNAs are packaged as diversely composed ribonucleoprotein particles with heterogeneous copy number states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.13.603387. [PMID: 39071419 PMCID: PMC11275876 DOI: 10.1101/2024.07.13.603387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Localization of mRNAs to dendrites is a fundamental mechanism by which neurons achieve spatiotemporal control of gene expression. Translationally repressed neuronal mRNA transport granules, also referred to as ribonucleoprotein particles (RNPs), have been shown to be trafficked as single or low copy number RNPs and as larger complexes with multiple copies and/or species of mRNAs. However, there is little evidence of either population in intact neuronal circuits. Using single molecule fluorescence in situ hybridization studies in the dendrites of adult rat and mouse hippocampus, we provide evidence that supports the existence of multi-transcript RNPs with the constituents varying in amounts for each RNA species. By competing-off fluorescently labeled probe with serial increases of unlabeled probe, we detected stepwise decreases in Arc RNP number and fluorescence intensity, suggesting Arc RNAs localize to dendrites in both low- and multiple-copy number RNPs. When probing for multiple mRNAs, we find that localized RNPs are heterogeneous in size and colocalization patterns that vary per RNA. Further, localized RNAs that are targeted by the same trans-acting element (FMRP) display greater levels of colocalization compared to an RNA not targeted by FMRP. Simultaneous visualization of a dozen FMRP-targeted mRNA species using highly multiplexed imaging demonstrates that dendritic RNAs are mostly trafficked as heteromeric cargoes of multiple types of RNAs (at least one or more RNAs). Moreover, the composition of these RNA cargoes, as assessed by colocalization, correlates with the abundance of the transcripts even after accounting for the expected differences in colocalization based on expression. Collectively, these results suggest that dendritic RNPs are packaged as heterogeneous co-assemblies of different mRNAs and that RNP contents may be driven, at least partially, by highly abundant dendritic RNAs; a model that favors efficiency over fine-tuned control for sustaining long-distance trafficking of thousands of messenger molecules.
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Affiliation(s)
- Renesa Tarannum
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Translational Biology, Medicine & Health Graduate Program, Virginia Tech, Blacksburg, Virginia
| | - Grace Mun
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Fatima Quddos
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Translational Biology, Medicine & Health Graduate Program, Virginia Tech, Blacksburg, Virginia
| | - Sharon A. Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | | | - Shannon Farris
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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Brandão-Teles C, Antunes ASLM, de Moraes Vrechi TA, Martins-de-Souza D. The Roles of hnRNP Family in the Brain and Brain-Related Disorders. Mol Neurobiol 2024; 61:3578-3595. [PMID: 37999871 DOI: 10.1007/s12035-023-03747-4] [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: 08/31/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to a complex family of RNA-binding proteins that are essential to control alternative splicing, mRNA trafficking, synaptic plasticity, stress granule formation, cell cycle regulation, and axonal transport. Over the past decade, hnRNPs have been associated with different brain disorders such as Alzheimer's disease, multiple sclerosis, and schizophrenia. Given their essential role in maintaining cell function and integrity, it is not surprising that dysregulated hnRNP levels lead to neurological implications. This review aims to explore the primary functions of hnRNPs in neurons, oligodendrocytes, microglia, and astrocytes, and their roles in brain disorders. We also discuss proteomics and other technologies and their potential for studying and evaluating hnRNPs in brain disorders, including the discovery of new therapeutic targets and possible pharmacological interventions.
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Affiliation(s)
- Caroline Brandão-Teles
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil.
| | - André S L M Antunes
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Talita Aparecida de Moraes Vrechi
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil.
- D'Or Institute for Research and Education (IDOR), São Paulo, Brazil.
- Experimental Medicine Research Cluster (EMRC), University of Campinas, Campinas, SP, 13083-862, Brazil.
- INCT in Modelling Human Complex Diseases with 3D Platforms (Model3D), São Paulo, Brazil.
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Instituto Nacional de Biomarcadores em Neuropsiquiatria, São Paulo, Brazil.
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4
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Pei X, Wang Z, He W, Li S, Chen X, Fan Z, Lan Y, Yuan L, Xu P. ER-tethered RNA-binding protein controls NADPH oxidase translation for hydrogen peroxide homeostasis. Redox Biol 2024; 71:103126. [PMID: 38503217 PMCID: PMC10963860 DOI: 10.1016/j.redox.2024.103126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/04/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024] Open
Abstract
Hydrogen peroxide (H2O2) functions as a signaling molecule in diverse cellular processes. While cells have evolved the capability to detect and manage changes in H2O2 levels, the mechanisms regulating key H2O2-producing enzymes to maintain optimal levels, especially in pancreatic beta cells with notably weak antioxidative defense, remain unclear. We found that the protein EI24 responds to changes in H2O2 concentration and regulates the production of H2O2 by controlling the translation of NOX4, an enzyme that is constitutively active, achieved by recruiting an RNA-binding protein, RTRAF, to the 3'-UTR of Nox4. Depleting EI24 results in RTRAF relocating into the nucleus, releasing the brake on NOX4 translation. The excessive production of H2O2 by liberated NOX4 further suppresses the translation of the key transcription factor MafA, ultimately preventing its binding to the Ins2 gene promoter and subsequent transcription of insulin. Treatment with a specific NOX4 inhibitor or the antioxidant NAC reversed these effects and alleviated the diabetic symptoms in beta-cell specific Ei24-KO mice. This study revealed a new mechanism through which cells regulate oxidative stress at the translational level, involving an ER-tethered RNA-binding protein that controls the expression of the key H2O2-producing enzyme NOX4.
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Affiliation(s)
- Xintong Pei
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhe Wang
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenting He
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shunqin Li
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaowei Chen
- Center for High Throughput Sequencing, Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhen Fan
- Center for High Throughput Sequencing, Core Facility for Protein Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yongguang Lan
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lin Yuan
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Pingyong Xu
- Key Laboratory of Biomacromolecules (CAS), CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China; Department of Clinical Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
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5
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Anadolu MN, Sun J, Li JTY, Graber TE, Ortega J, Sossin WS. Puromycin reveals a distinct conformation of neuronal ribosomes. Proc Natl Acad Sci U S A 2024; 121:e2306993121. [PMID: 38315848 PMCID: PMC10873636 DOI: 10.1073/pnas.2306993121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 01/03/2024] [Indexed: 02/07/2024] Open
Abstract
Puromycin is covalently added to the nascent chain of proteins by the peptidyl transferase activity of the ribosome and the dissociation of the puromycylated peptide typically follows this event. It was postulated that blocking the translocation of the ribosome with emetine could retain the puromycylated peptide on the ribosome, but evidence against this has recently been published [Hobson et al., Elife 9, e60048 (2020); and Enam et al., Elife 9, e60303 (2020)]. In neurons, puromycylated nascent chains remain in the ribosome even in the absence of emetine, yet direct evidence for this has been lacking. Using biochemistry and cryoelectron microscopy, we show that the puromycylated peptides remain in the ribosome exit channel in the large subunit in a subset of neuronal ribosomes stalled in the hybrid state. These results validate previous experiments to localize stalled polysomes in neurons and provide insight into how neuronal ribosomes are stalled. Moreover, in these hybrid-state neuronal ribosomes, anisomycin, which usually blocks puromycylation, competes poorly with puromycin in the puromycylation reaction, allowing a simple assay to determine the proportion of nascent chains that are stalled in this state. In early hippocampal neuronal cultures, over 50% of all nascent peptides are found in these stalled polysomes. These results provide insights into the stalling mechanisms of neuronal ribosomes and suggest that puromycylated peptides can be used to reveal subcellular sites of hybrid-state stalled ribosomes in neurons.
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Affiliation(s)
- Mina N. Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QCH3A 2B4, Canada
| | - Jingyu Sun
- Department of Anatomy and Cell Biology, McGill University, Montreal, QCH3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, QCH3G 0B1, Canada
| | - Jewel T.-Y. Li
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QCH3A 2B4, Canada
| | - Tyson E. Graber
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QCH3A 2B4, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, QCH3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, QCH3G 0B1, Canada
| | - Wayne S. Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QCH3A 2B4, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, QCH3A 0C7, Canada
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6
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Rosa E Silva I, Smetana JHC, de Oliveira JF. A comprehensive review on DDX3X liquid phase condensation in health and neurodevelopmental disorders. Int J Biol Macromol 2024; 259:129330. [PMID: 38218270 DOI: 10.1016/j.ijbiomac.2024.129330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/22/2023] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
DEAD-box helicases are global regulators of liquid-liquid phase separation (LLPS), a process that assembles membraneless organelles inside cells. An outstanding member of the DEAD-box family is DDX3X, a multi-functional protein that plays critical roles in RNA metabolism, including RNA transcription, splicing, nucleocytoplasmic export, and translation. The diverse functions of DDX3X result from its ability to bind and remodel RNA in an ATP-dependent manner. This capacity enables the protein to act as an RNA chaperone and an RNA helicase, regulating ribonucleoprotein complex assembly. DDX3X and its orthologs from mouse, yeast (Ded1), and C. elegans (LAF-1) can undergo LLPS, driving the formation of neuronal granules, stress granules, processing bodies or P-granules. DDX3X has been related to several human conditions, including neurodevelopmental disorders, such as intellectual disability and autism spectrum disorder. Although the research into the pathogenesis of aberrant biomolecular condensation in neurodegenerative diseases is increasing rapidly, the role of LLPS in neurodevelopmental disorders is underexplored. This review summarizes current findings relevant for DDX3X phase separation in neurodevelopment and examines how disturbances in the LLPS process can be related to neurodevelopmental disorders.
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Affiliation(s)
- Ivan Rosa E Silva
- Brazilian Biosciences National Laboratory, Center for Research in Energy and Materials, Campinas, SP, Brazil
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7
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Naskar A, Nayak A, Salaikumaran MR, Vishal SS, Gopal PP. Phase separation and pathologic transitions of RNP condensates in neurons: implications for amyotrophic lateral sclerosis, frontotemporal dementia and other neurodegenerative disorders. Front Mol Neurosci 2023; 16:1242925. [PMID: 37720552 PMCID: PMC10502346 DOI: 10.3389/fnmol.2023.1242925] [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: 06/20/2023] [Accepted: 08/21/2023] [Indexed: 09/19/2023] Open
Abstract
Liquid-liquid phase separation results in the formation of dynamic biomolecular condensates, also known as membrane-less organelles, that allow for the assembly of functional compartments and higher order structures within cells. Multivalent, reversible interactions between RNA-binding proteins (RBPs), including FUS, TDP-43, and hnRNPA1, and/or RNA (e.g., RBP-RBP, RBP-RNA, RNA-RNA), result in the formation of ribonucleoprotein (RNP) condensates, which are critical for RNA processing, mRNA transport, stability, stress granule assembly, and translation. Stress granules, neuronal transport granules, and processing bodies are examples of cytoplasmic RNP condensates, while the nucleolus and Cajal bodies are representative nuclear RNP condensates. In neurons, RNP condensates promote long-range mRNA transport and local translation in the dendrites and axon, and are essential for spatiotemporal regulation of gene expression, axonal integrity and synaptic function. Mutations of RBPs and/or pathologic mislocalization and aggregation of RBPs are hallmarks of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease. ALS/FTD-linked mutations of RBPs alter the strength and reversibility of multivalent interactions with other RBPs and RNAs, resulting in aberrant phase transitions. These aberrant RNP condensates have detrimental functional consequences on mRNA stability, localization, and translation, and ultimately lead to compromised axonal integrity and synaptic function in disease. Pathogenic protein aggregation is dependent on various factors, and aberrant dynamically arrested RNP condensates may serve as an initial nucleation step for pathologic aggregate formation. Recent studies have focused on identifying mechanisms by which neurons resolve phase transitioned condensates to prevent the formation of pathogenic inclusions/aggregates. The present review focuses on the phase separation of neurodegenerative disease-linked RBPs, physiological functions of RNP condensates, and the pathologic role of aberrant phase transitions in neurodegenerative disease, particularly ALS/FTD. We also examine cellular mechanisms that contribute to the resolution of aberrant condensates in neurons, and potential therapeutic approaches to resolve aberrantly phase transitioned condensates at a molecular level.
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Affiliation(s)
- Aditi Naskar
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Asima Nayak
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | | | - Sonali S. Vishal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Pallavi P. Gopal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT, United States
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8
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Çağlayan E, Turan K. An in silico prediction of interaction models of influenza A virus PA and human C14orf166 protein from yeast-two-hybrid screening data. Proteins 2023; 91:1235-1244. [PMID: 37265372 DOI: 10.1002/prot.26534] [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: 08/17/2022] [Revised: 05/13/2023] [Accepted: 05/18/2023] [Indexed: 06/03/2023]
Abstract
The human C14orf166 protein, also known as RNA transcription, translation, and transport factor, shows positive modulatory activity on the cellular RNA polymerase II enzyme. This protein is a component of the tRNA-splicing ligase complex and is involved in RNA metabolism. It also functions in the nucleo-cytoplasmic transport of RNA molecules. The C14orf166 protein has been reported to be associated with some types of cancer. It has been shown that the C14orf166 protein binds to the influenza A virus RNA polymerase PA subunit and has a stimulating effect on viral replication. In this study, candidate interactor proteins for influenza A virus PA protein were screened with a Y2H assay using HEK293 Matchmaker cDNA. The C14orf166 protein fragments in different sizes were found to interact with the PA. The three-dimensional structures of the viral PA and C14orf166 proteins interacting with the PA were generated using the I-TASSER algorithm. The interaction models between these proteins were predicted with the ClusPro protein docking algorithm and analyzed with PyMol software. The results revealed that the carboxy-terminal end of the C14orf166 protein is involved in this interaction, and it is highly possible that it binds to the carboxy-terminal of the PA protein. Although amino acid residues in the interaction area of the PA protein with the C14orf166 showed distribution from 450th to 700th position, the intense interaction region was revealed to be at amino acid positions 610-630.
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Affiliation(s)
- Elif Çağlayan
- University of Health Sciences Kartal Koşuyolu High Speciality Educational and Research Hospital, Istanbul, Turkey
| | - Kadir Turan
- Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, Marmara University, Istanbul, Turkey
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9
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Hildebrandt RP, Moss KR, Janusz-Kaminska A, Knudson LA, Denes LT, Saxena T, Boggupalli DP, Li Z, Lin K, Bassell GJ, Wang ET. Muscleblind-like proteins use modular domains to localize RNAs by riding kinesins and docking to membranes. Nat Commun 2023; 14:3427. [PMID: 37296096 PMCID: PMC10256740 DOI: 10.1038/s41467-023-38923-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
RNA binding proteins (RBPs) act as critical facilitators of spatially regulated gene expression. Muscleblind-like (MBNL) proteins, implicated in myotonic dystrophy and cancer, localize RNAs to myoblast membranes and neurites through unknown mechanisms. We find that MBNL forms motile and anchored granules in neurons and myoblasts, and selectively associates with kinesins Kif1bα and Kif1c through its zinc finger (ZnF) domains. Other RBPs with similar ZnFs associate with these kinesins, implicating a motor-RBP specificity code. MBNL and kinesin perturbation leads to widespread mRNA mis-localization, including depletion of Nucleolin transcripts from neurites. Live cell imaging and fractionation reveal that the unstructured carboxy-terminal tail of MBNL1 allows for anchoring at membranes. An approach, termed RBP Module Recruitment and Imaging (RBP-MRI), reconstitutes kinesin- and membrane-recruitment functions using MBNL-MS2 coat protein fusions. Our findings decouple kinesin association, RNA binding, and membrane anchoring functions of MBNL while establishing general strategies for studying multi-functional, modular domains of RBPs.
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Affiliation(s)
- Ryan P Hildebrandt
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kathryn R Moss
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Luke A Knudson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Lance T Denes
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Tanvi Saxena
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Devi Prasad Boggupalli
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Zhuangyue Li
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kun Lin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Eric T Wang
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
- Myology Institute, University of Florida, Gainesville, FL, USA.
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10
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Anadolu MN, Sun J, Kailasam S, Chalkiadaki K, Krimbacher K, Li JTY, Markova T, Jafarnejad SM, Lefebvre F, Ortega J, Gkogkas CG, Sossin WS. Ribosomes in RNA Granules Are Stalled on mRNA Sequences That Are Consensus Sites for FMRP Association. J Neurosci 2023; 43:2440-2459. [PMID: 36849416 PMCID: PMC10082463 DOI: 10.1523/jneurosci.1002-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 03/01/2023] Open
Abstract
Local translation in neurons is partly mediated by the reactivation of stalled polysomes. Stalled polysomes may be enriched within the granule fraction, defined as the pellet of sucrose gradients used to separate polysomes from monosomes. The mechanism of how elongating ribosomes are reversibly stalled and unstalled on mRNAs is still unclear. In the present study, we characterize the ribosomes in the granule fraction using immunoblotting, cryogenic electron microscopy (cryo-EM), and ribosome profiling. We find that this fraction, isolated from 5-d-old rat brains of both sexes, is enriched in proteins implicated in stalled polysome function, such as the fragile X mental retardation protein (FMRP) and Up-frameshift mutation 1 homologue. Cryo-EM analysis of ribosomes in this fraction indicates they are stalled, mainly in the hybrid state. Ribosome profiling of this fraction reveals (1) an enrichment for footprint reads of mRNAs that interact with FMRPs and are associated with stalled polysomes, (2) an abundance of footprint reads derived from mRNAs of cytoskeletal proteins implicated in neuronal development, and (3) increased ribosome occupancy on mRNAs encoding RNA binding proteins. Compared with those usually found in ribosome profiling studies, the footprint reads were longer and were mapped to reproducible peaks in the mRNAs. These peaks were enriched in motifs previously associated with mRNAs cross-linked to FMRP in vivo, independently linking the ribosomes in the granule fraction to the ribosomes associated with FMRP in the cell. The data supports a model in which specific sequences in mRNAs act to stall ribosomes during translation elongation in neurons.SIGNIFICANCE STATEMENT Neurons send mRNAs to synapses in RNA granules, where they are not translated until an appropriate stimulus is given. Here, we characterize a granule fraction obtained from sucrose gradients and show that polysomes in this fraction are stalled on consensus sequences in a specific state of translational arrest with extended ribosome-protected fragments. This finding greatly increases our understanding of how neurons use specialized mechanisms to regulate translation and suggests that many studies on neuronal translation may need to be re-evaluated to include the large fraction of neuronal polysomes found in the pellet of sucrose gradients used to isolate polysomes.
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Affiliation(s)
- Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Jingyu Sun
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Senthilkumar Kailasam
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Kleanthi Chalkiadaki
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Konstanze Krimbacher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck Austria Division of Biomedical Research, A-6020 Innsbruck, Austria
| | - Jewel T-Y Li
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Teodora Markova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Seyed M Jafarnejad
- Patrick G, Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland BT9 7AE, United Kingdom
| | - Francois Lefebvre
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Christos G Gkogkas
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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11
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Wijegunawardana D, Vishal SS, Venkatesh N, Gopal PP. Ataxin-2 polyglutamine expansions aberrantly sequester TDP-43, drive ribonucleoprotein condensate transport dysfunction and suppress local translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526372. [PMID: 36778347 PMCID: PMC9915502 DOI: 10.1101/2023.01.30.526372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Altered RNA metabolism is a common pathogenic mechanism linked to familial and sporadic Amyotrophic lateral sclerosis (ALS). ALS is characterized by mislocalization and aggregation of TDP-43, an RNA-binding protein (RBP) with multiple roles in post-transcriptional RNA processing. Recent studies have identified genetic interactions between TDP-43 and Ataxin-2, a polyglutamine (polyQ) RBP in which intermediate length polyQ expansions confer increased ALS risk. Here, we used live-cell confocal imaging, photobleaching and translation reporter assays to study the localization, transport dynamics and mRNA regulatory functions of TDP-43/Ataxin-2 in rodent primary cortical neurons. We show that Ataxin-2 polyQ expansions aberrantly sequester TDP-43 within ribonucleoprotein (RNP) condensates, and disrupt both its motility along the axon and liquid-like properties. Our data suggest that Ataxin-2 governs motility and translation of neuronal RNP condensates and that Ataxin-2 polyQ expansions fundamentally perturb spatial localization of mRNA and suppress local translation. Overall, these results indicate Ataxin-2 polyQ expansions have detrimental effects on stability, localization, and translation of transcripts critical for axonal and cytoskeletal integrity, particularly important for motor neurons.
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12
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Bourke AM, Schwarz A, Schuman EM. De-centralizing the Central Dogma: mRNA translation in space and time. Mol Cell 2023; 83:452-468. [PMID: 36669490 DOI: 10.1016/j.molcel.2022.12.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/16/2022] [Accepted: 12/28/2022] [Indexed: 01/20/2023]
Abstract
As our understanding of the cell interior has grown, we have come to appreciate that most cellular operations are localized, that is, they occur at discrete and identifiable locations or domains. These cellular domains contain enzymes, machines, and other components necessary to carry out and regulate these localized operations. Here, we review these features of one such operation: the localization and translation of mRNAs within subcellular compartments observed across cell types and organisms. We describe the conceptual advantages and the "ingredients" and mechanisms of local translation. We focus on the nature and features of localized mRNAs, how they travel and get localized, and how this process is regulated. We also evaluate our current understanding of protein synthesis machines (ribosomes) and their cadre of regulatory elements, that is, the translation factors.
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Affiliation(s)
- Ashley M Bourke
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Andre Schwarz
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany.
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13
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Nabariya DK, Heinz A, Derksen S, Krauß S. Intracellular and intercellular transport of RNA organelles in CXG repeat disorders: The strength of weak ties. Front Mol Biosci 2022; 9:1000932. [PMID: 36589236 PMCID: PMC9800848 DOI: 10.3389/fmolb.2022.1000932] [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: 07/22/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
RNA is a vital biomolecule, the function of which is tightly spatiotemporally regulated. RNA organelles are biological structures that either membrane-less or surrounded by membrane. They are produced by the all the cells and indulge in vital cellular mechanisms. They include the intracellular RNA granules and the extracellular exosomes. RNA granules play an essential role in intracellular regulation of RNA localization, stability and translation. Aberrant regulation of RNA is connected to disease development. For example, in microsatellite diseases such as CXG repeat expansion disorders, the mutant CXG repeat RNA's localization and function are affected. RNA is not only transported intracellularly but can also be transported between cells via exosomes. The loading of the exosomes is regulated by RNA-protein complexes, and recent studies show that cytosolic RNA granules and exosomes share common content. Intracellular RNA granules and exosome loading may therefore be related. Exosomes can also transfer pathogenic molecules of CXG diseases from cell to cell, thereby driving disease progression. Both intracellular RNA granules and extracellular RNA vesicles may serve as a source for diagnostic and treatment strategies. In therapeutic approaches, pharmaceutical agents may be loaded into exosomes which then transport them to the desired cells/tissues. This is a promising target specific treatment strategy with few side effects. With respect to diagnostics, disease-specific content of exosomes, e.g., RNA-signatures, can serve as attractive biomarker of central nervous system diseases detecting early physiological disturbances, even before symptoms of neurodegeneration appear and irreparable damage to the nervous system occurs. In this review, we summarize the known function of cytoplasmic RNA granules and extracellular vesicles, as well as their role and dysfunction in CXG repeat expansion disorders. We also provide a summary of established protocols for the isolation and characterization of both cytoplasmic and extracellular RNA organelles.
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Affiliation(s)
| | | | | | - Sybille Krauß
- Human Biology/Neurobiology, Institute of Biology, Faculty IV, School of Science and Technology, University of Siegen, Siegen, Germany
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14
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Cappelli S, Spalloni A, Feiguin F, Visani G, Šušnjar U, Brown AL, De Bardi M, Borsellino G, Secrier M, Phatnani H, Romano M, Fratta P, Longone P, Buratti E. NOS1AP is a novel molecular target and critical factor in TDP-43 pathology. Brain Commun 2022; 4:fcac242. [PMID: 36267332 PMCID: PMC9576154 DOI: 10.1093/braincomms/fcac242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 07/05/2022] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
Many lines of evidence have highlighted the role played by heterogeneous nuclear ribonucleoproteins in amyotrophic lateral sclerosis. In this study, we have aimed to identify transcripts co-regulated by TAR DNA-binding protein 43 kDa and highly conserved heterogeneous nuclear ribonucleoproteins which have been previously shown to regulate TAR DNA-binding protein 43 kDa toxicity (deleted in azoospermia-associated protein 1, heterogeneous nuclear ribonucleoprotein -Q, -D, -K and -U). Using the transcriptome analyses, we have uncovered that Nitric Oxide Synthase 1 Adaptor Protein mRNA is a direct TAR DNA-binding protein 43 kDa target, and in flies, its modulation alone can rescue TAR DNA-binding protein 43 kDa pathology. In primary mouse cortical neurons, we show that TAR DNA-binding protein 43 kDa mediated downregulation of Nitric Oxide Synthase 1 Adaptor Protein expression strongly affects the NMDA-receptor signalling pathway. In human patients, the downregulation of Nitric Oxide Synthase 1 Adaptor Protein mRNA strongly correlates with TAR DNA-binding protein 43 kDa proteinopathy as measured by cryptic Stathmin-2 and Unc-13 homolog A cryptic exon inclusion. Overall, our results demonstrate that Nitric Oxide Synthase 1 Adaptor Protein may represent a novel disease-relevant gene, potentially suitable for the development of new therapeutic strategies.
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Affiliation(s)
- Sara Cappelli
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Alida Spalloni
- Molecular Neurobiology, Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy
| | - Fabian Feiguin
- Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy
| | - Giulia Visani
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Urša Šušnjar
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Anna-Leigh Brown
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Marco De Bardi
- Neuroimmunology Unit, Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via Ardeatina 306-354, 00179 Rome, Italy
| | - Giovanna Borsellino
- Neuroimmunology Unit, Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via Ardeatina 306-354, 00179 Rome, Italy
| | - Maria Secrier
- UCL Genetics Institute, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Hemali Phatnani
- Center for Genomics of Neurodegenerative Disease, New York Genome Center, New York, NY 10013, USA
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, 34127 Trieste, Italy
| | - Pietro Fratta
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- UCL Genetics Institute, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Patrizia Longone
- Molecular Neurobiology, Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, Padriciano 99, 34149 Trieste, Italy
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15
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Costa RO, Martins LF, Tahiri E, Duarte CB. Brain-derived neurotrophic factor-induced regulation of RNA metabolism in neuronal development and synaptic plasticity. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1713. [PMID: 35075821 DOI: 10.1002/wrna.1713] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) plays multiple roles in the nervous system, including in neuronal development, in long-term synaptic potentiation in different brain regions, and in neuronal survival. Alterations in these regulatory mechanisms account for several diseases of the nervous system. The synaptic effects of BDNF mediated by activation of tropomyosin receptor kinase B (TrkB) receptors are partly mediated by stimulation of local protein synthesis which is now considered a ubiquitous feature in both presynaptic and postsynaptic compartments of the neuron. The capacity to locally synthesize proteins is of great relevance at several neuronal developmental stages, including during neurite development, synapse formation, and stabilization. The available evidence shows that the effects of BDNF-TrkB signaling on local protein synthesis regulate the structure and function of the developing and mature synapses. While a large number of studies have illustrated a wide range of effects of BDNF on the postsynaptic proteome, a growing number of studies also point to presynaptic effects of the neurotrophin in the local regulation of the protein composition at the presynaptic level. Here, we will review the latest evidence on the role of BDNF in local protein synthesis, comparing the effects on the presynaptic and postsynaptic compartments. Additionally, we overview the relevance of BDNF-associated local protein synthesis in neuronal development and synaptic plasticity, at the presynaptic and postsynaptic compartments, and their relevance in terms of disease. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Export and Localization > RNA Localization.
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Affiliation(s)
- Rui O Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Luís F Martins
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Emanuel Tahiri
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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16
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Kipper K, Mansour A, Pulk A. Neuronal RNA granules are ribosome complexes stalled at the pre-translocation state. J Mol Biol 2022; 434:167801. [PMID: 36038000 DOI: 10.1016/j.jmb.2022.167801] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/20/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022]
Abstract
The polarized cell morphology of neurons dictates many neuronal processes, including the axodendridic transport of specific mRNAs and subsequent translation. mRNAs together with ribosomes and RNA-binding proteins form RNA granules that are targeted to axodendrites for localized translation in neurons. It has been established that localized protein synthesis in neurons is essential for long-term memory formation, synaptic plasticity, and neurodegeneration. We have used proteomics and electron microscopy to characterize neuronal RNA granules (nRNAg) isolated from rat brain tissues or human neuroblastoma. We show that ribosome containing RNA granules are morula-like structures when visualized by electron microscopy. Crosslinking-coupled mass-spectrometry identified potential G3BP2 binding site on the ribosome near the eIF3d-binding site on the 40S ribosomal subunit. We used cryo-EM to resolve the structure of the ribosome-component of nRNAg. The cryo-EM reveals that predominant particles in nRNAg are 80S ribosomes, resembling the pre-translocation state where tRNA's are in the hybrid A/P and P/E site. We also describe a new kind of principal motion of the ribosome, which we call the rocking motion.
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Affiliation(s)
- Kalle Kipper
- Structural Biology Unit, Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Abbas Mansour
- Structural Biology Unit, Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Arto Pulk
- Structural Biology Unit, Institute of Technology, University of Tartu, Tartu 50411, Estonia.
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17
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Hoye ML, Calviello L, Poff AJ, Ejimogu NE, Newman CR, Montgomery MD, Ou J, Floor SN, Silver DL. Aberrant cortical development is driven by impaired cell cycle and translational control in a DDX3X syndrome model. eLife 2022; 11:e78203. [PMID: 35762573 PMCID: PMC9239684 DOI: 10.7554/elife.78203] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/25/2022] [Indexed: 12/14/2022] Open
Abstract
Mutations in the RNA helicase, DDX3X, are a leading cause of Intellectual Disability and present as DDX3X syndrome, a neurodevelopmental disorder associated with cortical malformations and autism. Yet, the cellular and molecular mechanisms by which DDX3X controls cortical development are largely unknown. Here, using a mouse model of Ddx3x loss-of-function we demonstrate that DDX3X directs translational and cell cycle control of neural progenitors, which underlies precise corticogenesis. First, we show brain development is sensitive to Ddx3x dosage; complete Ddx3x loss from neural progenitors causes microcephaly in females, whereas hemizygous males and heterozygous females show reduced neurogenesis without marked microcephaly. In addition, Ddx3x loss is sexually dimorphic, as its paralog, Ddx3y, compensates for Ddx3x in the developing male neocortex. Using live imaging of progenitors, we show that DDX3X promotes neuronal generation by regulating both cell cycle duration and neurogenic divisions. Finally, we use ribosome profiling in vivo to discover the repertoire of translated transcripts in neural progenitors, including those which are DDX3X-dependent and essential for neurogenesis. Our study reveals invaluable new insights into the etiology of DDX3X syndrome, implicating dysregulated progenitor cell cycle dynamics and translation as pathogenic mechanisms.
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Affiliation(s)
- Mariah L Hoye
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Lorenzo Calviello
- Centre for Functional Genomics, Human TechnopoleMilanItaly
- Centre for Computational Biology, Human TechnopoleMilanItaly
| | - Abigail J Poff
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Nna-Emeka Ejimogu
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Carly R Newman
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Maya D Montgomery
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Jianhong Ou
- Department of Cell Biology, Duke University Medical CenterDurhamUnited States
- Duke Regeneration Center, Duke University Medical CenterDurhamUnited States
| | - Stephen N Floor
- Department of Cell and Tissue Biology, UCSFSan FranciscoUnited States
- Helen Diller Family Comprehensive Cancer CenterSan FranciscoUnited States
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
- Department of Cell Biology, Duke University Medical CenterDurhamUnited States
- Duke Regeneration Center, Duke University Medical CenterDurhamUnited States
- Department of Neurobiology, Duke University Medical CenterDurhamUnited States
- Duke Institute for Brain Sciences, Duke University Medical CenterDurhamUnited States
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18
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Vishal SS, Wijegunawardana D, Salaikumaran MR, Gopal PP. Sequence Determinants of TDP-43 Ribonucleoprotein Condensate Formation and Axonal Transport in Neurons. Front Cell Dev Biol 2022; 10:876893. [PMID: 35646935 PMCID: PMC9133736 DOI: 10.3389/fcell.2022.876893] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/21/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations in TDP-43, a RNA-binding protein with multiple functions in RNA metabolism, cause amyotrophic lateral sclerosis (ALS), but it is uncertain how defects in RNA biology trigger motor neuron degeneration. TDP-43 is a major constituent of ribonucleoprotein (RNP) granules, phase separated biomolecular condensates that regulate RNA splicing, mRNA transport, and translation. ALS-associated TDP-43 mutations, most of which are found in the low complexity domain, promote aberrant liquid to solid phase transitions and impair the dynamic liquid-like properties and motility of RNP transport granules in neurons. Here, we perform a comparative analysis of ALS-linked mutations and TDP-43 variants in order to identify critical structural elements, aromatic and charged residues that are key determinants of TDP-43 RNP transport and condensate formation in neurons. We find that A315T and Q343R disease-linked mutations and substitutions of aromatic residues within the α-helical domain and LARKS, show the most severe defects in TDP-43 RNP granule transport and impair both anterograde and retrograde motility. F313L and F313-6L/Y substitutions of one or both phenylalanine residues in LARKS suggest the aromatic rings are important for TDP-43 RNP transport. Similarly, W334F/L substitutions of the tryptophan residue in the α-helical domain, impair TDP-43 RNP motility (W334L) or anterograde transport (W334F). We also show that R293A and R293K mutations, which disrupt the only RGG in the LCD, profoundly reduce long-range, directed transport and net velocity of TDP-43 RNP granules. In the disordered regions flanking the α-helical domain, we find that F283Y, F397Y or Y374F substitutions of conserved GF/G and SYS motifs, also impair anterograde and/or retrograde motility, possibly by altering hydrophobicity. Similarly, ALS-linked mutations in disordered regions distant from the α-helical domain also show anterograde transport deficits, consistent with previous findings, but these mutations are less severe than A315T and Q343R. Overall our findings demonstrate that the conserved α-helical domain, phenylalanine residues within LARKS and RGG motif are key determinants of TDP-43 RNP transport, suggesting they may mediate efficient recruitment of motors and adaptor proteins. These results offer a possible mechanism underlying ALS-linked TDP-43 defects in axonal transport and homeostasis.
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Affiliation(s)
- Sonali S. Vishal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | | | | | - Pallavi P. Gopal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT, United States
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19
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Microtubule and Actin Cytoskeletal Dynamics in Male Meiotic Cells of Drosophila melanogaster. Cells 2022; 11:cells11040695. [PMID: 35203341 PMCID: PMC8870657 DOI: 10.3390/cells11040695] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 01/12/2023] Open
Abstract
Drosophila dividing spermatocytes offer a highly suitable cell system in which to investigate the coordinated reorganization of microtubule and actin cytoskeleton systems during cell division of animal cells. Like male germ cells of mammals, Drosophila spermatogonia and spermatocytes undergo cleavage furrow ingression during cytokinesis, but abscission does not take place. Thus, clusters of primary and secondary spermatocytes undergo meiotic divisions in synchrony, resulting in cysts of 32 secondary spermatocytes and then 64 spermatids connected by specialized structures called ring canals. The meiotic spindles in Drosophila males are substantially larger than the spindles of mammalian somatic cells and exhibit prominent central spindles and contractile rings during cytokinesis. These characteristics make male meiotic cells particularly amenable to immunofluorescence and live imaging analysis of the spindle microtubules and the actomyosin apparatus during meiotic divisions. Moreover, because the spindle assembly checkpoint is not robust in spermatocytes, Drosophila male meiosis allows investigating of whether gene products required for chromosome segregation play additional roles during cytokinesis. Here, we will review how the research studies on Drosophila male meiotic cells have contributed to our knowledge of the conserved molecular pathways that regulate spindle microtubules and cytokinesis with important implications for the comprehension of cancer and other diseases.
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20
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Verzat C, Harley J, Patani R, Luisier R. Image-based deep learning reveals the responses of human motor neurons to stress and VCP-related ALS. Neuropathol Appl Neurobiol 2021; 48:e12770. [PMID: 34595747 PMCID: PMC9298273 DOI: 10.1111/nan.12770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 11/28/2022]
Abstract
AIMS Although morphological attributes of cells and their substructures are recognised readouts of physiological or pathophysiological states, these have been relatively understudied in amyotrophic lateral sclerosis (ALS) research. METHODS In this study, we integrate multichannel fluorescence high-content microscopy data with deep learning imaging methods to reveal-directly from unsegmented images-novel neurite-associated morphological perturbations associated with (ALS-causing) VCP-mutant human motor neurons (MNs). RESULTS Surprisingly, we reveal that previously unrecognised disease-relevant information is withheld in broadly used and often considered 'generic' biological markers of nuclei (DAPI) and neurons ( β III-tubulin). Additionally, we identify changes within the information content of ALS-related RNA binding protein (RBP) immunofluorescence imaging that is captured in VCP-mutant MN cultures. Furthermore, by analysing MN cultures exposed to different extrinsic stressors, we show that heat stress recapitulates key aspects of ALS. CONCLUSIONS Our study therefore reveals disease-relevant information contained in a range of both generic and more specific fluorescent markers and establishes the use of image-based deep learning methods for rapid, automated and unbiased identification of biological hypotheses.
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Affiliation(s)
- Colombine Verzat
- Genomics and Health Informatics Group, Idiap Research Institute, Martigny, Switzerland
| | - Jasmine Harley
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Rickie Patani
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Raphaëlle Luisier
- Genomics and Health Informatics Group, Idiap Research Institute, Martigny, Switzerland
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21
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Corbet GA, Wheeler JR, Parker R, Weskamp K. TDP43 ribonucleoprotein granules: physiologic function to pathologic aggregates. RNA Biol 2021; 18:128-138. [PMID: 34412568 DOI: 10.1080/15476286.2021.1963099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Ribonucleoprotein (RNP) assemblies are ubiquitous in eukaryotic cells and have functions throughout RNA transcription, splicing, and stability. Of the RNA-binding proteins that form RNPs, TAR DNA-binding protein of 43 kD (TDP43) is of particular interest due to its essential nature and its association with disease. TDP43 plays critical roles in RNA metabolism, many of which require its recruitment to RNP granules such as stress granules, myo-granules, and neuronal transport granules. Moreover, the presence of cytoplasmic TDP43-positive inclusions is a pathological hallmark of several neurodegenerative diseases. Despite the pervasiveness of TDP43 aggregates, TDP43 mutations are exceedingly rare, suggesting that aggregation may be linked to dysregulation of TDP43 function. Oligomerization is a part of normal TDP43 function; thus, it is of interest to understand what triggers the irreversible aggregation that is seen in disease. Herein, we examine TDP43 functions, particularly in RNP granules, and the mechanisms which may explain pathological TDP43 aggregation.
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Affiliation(s)
- Giulia Ada Corbet
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | | | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,Department of Chemistry, Howard Hughes Medical Institute, Chevy Chase, MD, USA
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22
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Rajgor D, Welle TM, Smith KR. The Coordination of Local Translation, Membranous Organelle Trafficking, and Synaptic Plasticity in Neurons. Front Cell Dev Biol 2021; 9:711446. [PMID: 34336865 PMCID: PMC8317219 DOI: 10.3389/fcell.2021.711446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Neurons are highly complex polarized cells, displaying an extraordinary degree of spatial compartmentalization. At presynaptic and postsynaptic sites, far from the cell body, local protein synthesis is utilized to continually modify the synaptic proteome, enabling rapid changes in protein production to support synaptic function. Synapses undergo diverse forms of plasticity, resulting in long-term, persistent changes in synapse strength, which are paramount for learning, memory, and cognition. It is now well-established that local translation of numerous synaptic proteins is essential for many forms of synaptic plasticity, and much work has gone into deciphering the strategies that neurons use to regulate activity-dependent protein synthesis. Recent studies have pointed to a coordination of the local mRNA translation required for synaptic plasticity and the trafficking of membranous organelles in neurons. This includes the co-trafficking of RNAs to their site of action using endosome/lysosome “transports,” the regulation of activity-dependent translation at synapses, and the role of mitochondria in fueling synaptic translation. Here, we review our current understanding of these mechanisms that impact local translation during synaptic plasticity, providing an overview of these novel and nuanced regulatory processes involving membranous organelles in neurons.
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Affiliation(s)
- Dipen Rajgor
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Theresa M Welle
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
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23
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Rajič Bumber J, Pilipović K, Janković T, Dolenec P, Gržeta N, Križ J, Župan G. Repetitive Traumatic Brain Injury Is Associated With TDP-43 Alterations, Neurodegeneration, and Glial Activation in Mice. J Neuropathol Exp Neurol 2021; 80:2-14. [PMID: 33212475 DOI: 10.1093/jnen/nlaa130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence points to a relationship between repetitive mild traumatic brain injury (mTBI), the Tar DNA binding protein 43 (TDP-43) pathology and some neurodegenerative diseases, but the underlying pathophysiological mechanisms are still unknown. We examined TDP-43 regulation, neurodegeneration, and glial responses following repetitive mTBI in nontransgenic mice and in animals with overexpression of human mutant TDP-43 protein (TDP-43G348C). In the frontal cortices of the injured nontransgenic animals, early TDP-43 cytoplasmatic translocation and overexpression of the protein and its pathological forms were detected. In the injured animals of both genotypes, neurodegeneration and pronounced glial activity were detected in the optic tract. In TDP-43G348C mice, these changes were significantly higher at day 7 after the last mTBI compared with the values in the nontransgenic animals. Results of this study suggest that the changes in the TDP-43 regulation in the frontal cortices of the nontransgenic animals were a transient stress response to the brain injury. Repetitive mTBI did not produce additional TDP-43 dysregulation or neurodegeneration or pronounced gliosis in the frontal cortex of TDP-43G348C mice. Our research also suggests that overexpression of mutated human TDP-43 possibly predisposes the brain to more intense neurodegeneration and glial activation in the optic tract after repetitive mTBI.
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Affiliation(s)
- Jelena Rajič Bumber
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Kristina Pilipović
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Tamara Janković
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Petra Dolenec
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Nika Gržeta
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jasna Križ
- Department of Psychiatry and Neuroscience, Faculty of Medicine, University of Laval, Quebec, QC, Canada
| | - Gordana Župan
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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24
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Connecting the "dots": RNP granule network in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119058. [PMID: 33989700 DOI: 10.1016/j.bbamcr.2021.119058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/01/2021] [Accepted: 05/07/2021] [Indexed: 12/26/2022]
Abstract
All cells contain ribonucleoprotein (RNP) granules - large membraneless structures composed of RNA and proteins. Recent breakthroughs in RNP granule research have brought a new appreciation of their crucial role in organising virtually all cellular processes. Cells widely exploit the flexible, dynamic nature of RNP granules to adapt to a variety of functional states and the ever-changing environment. Constant exchange of molecules between the different RNP granules connects them into a network. This network controls basal cellular activities and is remodelled to enable efficient stress response. Alterations in RNP granule structure and regulation have been found to lead to fatal human diseases. The interconnectedness of RNP granules suggests that the RNP granule network as a whole becomes affected in disease states such as a representative neurodegenerative disease amyotrophic lateral sclerosis (ALS). In this review, we summarize available evidence on the communication between different RNP granules and on the RNP granule network disruption as a primary ALS pathomechanism.
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25
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Amyotrophic Lateral Sclerosis and Frontotemporal Lobar Degenerations: Similarities in Genetic Background. Diagnostics (Basel) 2021; 11:diagnostics11030509. [PMID: 33805659 PMCID: PMC7998502 DOI: 10.3390/diagnostics11030509] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/06/2021] [Accepted: 03/11/2021] [Indexed: 12/27/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating, uniformly lethal progressive degenerative disorder of motor neurons that overlaps with frontotemporal lobar degeneration (FTLD) clinically, morphologically, and genetically. Although many distinct mutations in various genes are known to cause amyotrophic lateral sclerosis, it remains poorly understood how they selectively impact motor neuron biology and whether they converge on common pathways to cause neuronal degeneration. Many of the gene mutations are in proteins that share similar functions. They can be grouped into those associated with cell axon dynamics and those associated with cellular phagocytic machinery, namely protein aggregation and metabolism, apoptosis, and intracellular nucleic acid transport. Analysis of pathways implicated by mutant ALS genes has provided new insights into the pathogenesis of both familial forms of ALS (fALS) and sporadic forms (sALS), although, regrettably, this has not yet yielded definitive treatments. Many genes play an important role, with TARDBP, SQSTM1, VCP, FUS, TBK1, CHCHD10, and most importantly, C9orf72 being critical genetic players in these neurological disorders. In this mini-review, we will focus on the molecular mechanisms of these two diseases.
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26
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RNA-binding protein syncrip regulates starvation-induced hyperactivity in adult Drosophila. PLoS Genet 2021; 17:e1009396. [PMID: 33617535 PMCID: PMC7932510 DOI: 10.1371/journal.pgen.1009396] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/04/2021] [Accepted: 02/03/2021] [Indexed: 11/28/2022] Open
Abstract
How to respond to starvation determines fitness. One prominent behavioral response is increased locomotor activities upon starvation, also known as Starvation-Induced Hyperactivity (SIH). SIH is paradoxical as it promotes food seeking but also increases energy expenditure. Despite its importance in fitness, the genetic contributions to SIH as a behavioral trait remains unexplored. Here, we examined SIH in the Drosophila melanogaster Genetic Reference Panel (DGRP) and performed genome-wide association studies. We identified 23 significant loci, corresponding to 14 genes, significantly associated with SIH in adult Drosophila. Gene enrichment analyses indicated that genes encoding ion channels and mRNA binding proteins (RBPs) were most enriched in SIH. We are especially interested in RBPs because they provide a potential mechanism to quickly change protein expression in response to environmental challenges. Using RNA interference, we validated the role of syp in regulating SIH. syp encodes Syncrip (Syp), an RBP. While ubiquitous knockdown of syp led to semi-lethality in adult flies, adult flies with neuron-specific syp knockdown were viable and exhibited decreased SIH. Using the Temporal and Regional Gene Expression Targeting (TARGET) system, we further confirmed the role of Syp in adult neurons in regulating SIH. To determine how syp is regulated by starvation, we performed RNA-seq using the heads of flies maintained under either food or starvation conditions. RNA-seq analyses revealed that syp was alternatively spliced under starvation while its expression level was unchanged. We further generated an alternatively-spliced-exon-specific knockout (KO) line and found that KO flies showed reduced SIH. Together, this study demonstrates a significant genetic contribution to SIH as a behavioral trait, identifies syp as a SIH gene, and highlights the significance of RBPs and post-transcriptional processes in the brain in regulating behavioral responses to starvation. Animals living in the wild often face periods of starvation. How to physiologically and behaviorally respond to starvation is essential for survival. One behavioral response is Starvation-Induced Hyperactivity (SIH). We used the Drosophila melanogaster Genetic Reference Panel, derived from a wild population, to study the genetic basis of SIH. Our results show that there is a significant genetic contribution to SIH in this population, and that genes encoding RNA binding proteins (RBPs) are especially important. Using RNA interference and the TARGET system, we confirmed the role of an RBP Syp in adult neurons in SIH. Using RNA-seq and Western blotting, we found that syp was alternatively spliced under starvation while its expression level was unchanged. Further studies from syp exon-specific knockout flies showed that alternative splicing involving two exons in syp was important for SIH. Together, this study identifies syp as a SIH gene and highlights an essential role of post-transcriptional modification in regulating this behavior.
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27
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Dalla Costa I, Buchanan CN, Zdradzinski MD, Sahoo PK, Smith TP, Thames E, Kar AN, Twiss JL. The functional organization of axonal mRNA transport and translation. Nat Rev Neurosci 2021; 22:77-91. [PMID: 33288912 PMCID: PMC8161363 DOI: 10.1038/s41583-020-00407-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2020] [Indexed: 12/13/2022]
Abstract
Axons extend for tremendously long distances from the neuronal soma and make use of localized mRNA translation to rapidly respond to different extracellular stimuli and physiological states. The locally synthesized proteins support many different functions in both developing and mature axons, raising questions about the mechanisms by which local translation is organized to ensure the appropriate responses to specific stimuli. Publications over the past few years have uncovered new mechanisms for regulating the axonal transport and localized translation of mRNAs, with several of these pathways converging on the regulation of cohorts of functionally related mRNAs - known as RNA regulons - that drive axon growth, axon guidance, injury responses, axon survival and even axonal mitochondrial function. Recent advances point to these different regulatory pathways as organizing platforms that allow the axon's proteome to be modulated to meet its physiological needs.
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Affiliation(s)
- Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Courtney N Buchanan
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | | | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Elizabeth Thames
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
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28
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Ryan VH, Perdikari TM, Naik MT, Saueressig CF, Lins J, Dignon GL, Mittal J, Hart AC, Fawzi NL. Tyrosine phosphorylation regulates hnRNPA2 granule protein partitioning and reduces neurodegeneration. EMBO J 2021; 40:e105001. [PMID: 33349959 PMCID: PMC7849316 DOI: 10.15252/embj.2020105001] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 10/14/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
mRNA transport in neurons requires formation of transport granules containing many protein components, and subsequent alterations in phosphorylation status can release transcripts for translation. Further, mutations in a structurally disordered domain of the transport granule protein hnRNPA2 increase its aggregation and cause hereditary proteinopathy of neurons, myocytes, and bone. We examine in vitro hnRNPA2 granule component phase separation, partitioning specificity, assembly/disassembly, and the link to neurodegeneration. Transport granule components hnRNPF and ch-TOG interact weakly with hnRNPA2 yet partition specifically into liquid phase droplets with the low complexity domain (LC) of hnRNPA2, but not FUS LC. In vitro hnRNPA2 tyrosine phosphorylation reduces hnRNPA2 phase separation, prevents partitioning of hnRNPF and ch-TOG into hnRNPA2 LC droplets, and decreases aggregation of hnRNPA2 disease variants. The expression of chimeric hnRNPA2 D290V in Caenorhabditis elegans results in stress-induced glutamatergic neurodegeneration; this neurodegeneration is rescued by loss of tdp-1, suggesting gain-of-function toxicity. The expression of Fyn, a tyrosine kinase that phosphorylates hnRNPA2, reduces neurodegeneration associated with chimeric hnRNPA2 D290V. These data suggest a model where phosphorylation alters LC interaction specificity, aggregation, and toxicity.
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Affiliation(s)
- Veronica H Ryan
- Neuroscience Graduate ProgramBrown UniversityProvidenceRIUSA
| | | | - Mandar T Naik
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
| | | | - Jeremy Lins
- Department of NeuroscienceBrown UniversityProvidenceRIUSA
| | - Gregory L Dignon
- Department of Chemical and Biomolecular EngineeringLehigh UniversityBethlehemPAUSA
| | - Jeetain Mittal
- Department of Chemical and Biomolecular EngineeringLehigh UniversityBethlehemPAUSA
| | - Anne C Hart
- Department of NeuroscienceBrown UniversityProvidenceRIUSA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
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29
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Broix L, Turchetto S, Nguyen L. Coordination between Transport and Local Translation in Neurons. Trends Cell Biol 2021; 31:372-386. [PMID: 33526339 DOI: 10.1016/j.tcb.2021.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 11/15/2022]
Abstract
The axonal microtubules (MTs) support long-distance transport of cargoes that are dispatched to distinct cellular subcompartments. Among them, mRNAs are directly transported in membraneless ribonucleoprotein (RNP) granules that, together with ribosomes, can also hitchhike on fast-moving membrane-bound organelles for accurate transport along MTs. These organelles serve as platforms for mRNA translation, thus generating axonal foci of newly synthesized proteins. Local translation along axons not only supports MT network integrity but also modulates the processivity and function of molecular motors to allow proper trafficking of cargoes along MTs. Thus, identifying the mechanisms that coordinate axonal transport with local protein synthesis will shed new light on the processes underlying axon development and maintenance, whose deregulation often contribute to neurological disorders.
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Affiliation(s)
- Loïc Broix
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Silvia Turchetto
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Laurent Nguyen
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium.
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30
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Zhu G, Zhu Q, Zhang W, Hui C, Li Y, Yang M, Pang S, Li Y, Xue G, Chen H. Mitochondrial uncoupling protein 2 is regulated through heterogeneous nuclear ribonucleoprotein K in lead exposure models. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, TOXICOLOGY AND CARCINOGENESIS 2021; 39:1-16. [PMID: 33576715 DOI: 10.1080/26896583.2020.1854596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Synaptic plasticity plays an important role in learning and memory in the developing hippocampus. However, the precise molecular mechanism in lead exposure models remains to be studied. UCP2, an inner mitochondrial anion carrier, regulates synaptic plasticity through uncoupling neurons. And hnRNP K, an RNA binding protein, plays a role in modulating the expression of transcripts coding synaptic plasticity. We aim to investigate whether lead exposure affects UCP2 and hnRNP K expression levels. The Sprague-Dawley rats were exposed to different lead acetate concentrations (0 g/l, 0.5 g/l, 2.0 g/l) during gestational and lactational periods. PC12 cells were also exposed to different lead acetate concentrations (0 μM, 1 μM and 100 μM). We found that the expression levels of UCP2 and hnRNP K had significant declines in the lead exposure rat hippocampus and PC12 cells. Furthermore, the up-regulation of hnRNP K expression level could reverse the expression level of UCP2 in lead exposure models. In conclusion, these results suggest that lead exposure can reduce the expression level of UCP2 which is mediated by decreasing the expression level of hnRNP K.
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Affiliation(s)
- Gaochun Zhu
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Qian Zhu
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Wei Zhang
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Chen Hui
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Yuwen Li
- Queen Mary College, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Meiyuan Yang
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Shimin Pang
- Second Clinical College, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Yaobing Li
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Guoyong Xue
- Department of Anatomy, School of Medicine, Nanchang University, Nanchang, P.R. China
| | - Hongping Chen
- Department of Histology and Embryology, School of Medicine, Nanchang University, Nanchang, P.R. China
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31
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Wong CE, Jin LW, Chu YP, Wei WY, Ho PC, Tsai KJ. TDP-43 proteinopathy impairs mRNP granule mediated postsynaptic translation and mRNA metabolism. Theranostics 2021; 11:330-345. [PMID: 33391478 PMCID: PMC7681104 DOI: 10.7150/thno.51004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
Background: Local protein synthesis and mRNA metabolism mediated by mRNP granules in the dendrites and the postsynaptic compartment is essential for synaptic remodeling and plasticity in neuronal cells. Dysregulation of these processes caused by TDP-43 proteinopathy leads to neurodegenerative diseases, such as frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Methods: Using biochemical analysis and imaging techniques, including super-resolution microscopy, we provide evidence, for the first time, for the postsynaptic localization of TDP-43 in mammalian synapses and we show that TDP-43 is a component of neuronal mRNP granules. Results: With activity stimulation and various molecular approaches, we further demonstrate activity-dependent mRNP granule dynamics involving disassembly of mRNP granules, release of mRNAs, activation of local protein translation, and the impairment of granule disassembly in cellular, animal and human models of TDP-43 proteinopathy. Conclusion: Our study elucidates the interplay between TDP-43 and neuronal mRNP granules in normal physiology and TDP-43 proteinopathy in the regulation of local protein translation and mRNA metabolism in the postsynaptic compartment.
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Affiliation(s)
- Chia-En Wong
- Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, UC Davis Medical Center, California, USA
| | - Yuan-Ping Chu
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Yen Wei
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Chuan Ho
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kuen-Jer Tsai
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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32
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Abstract
RNA-binding proteins are a critical group of multifunctional proteins that precisely regulate all aspects of gene expression, from alternative splicing to mRNA trafficking, stability, and translation. Converging evidence highlights aberrant RNA metabolism as a common pathogenic mechanism in several neurodevelopmental and neurodegenerative diseases. However, dysregulation of disease-linked RNA-binding proteins results in widespread, often tissue-specific and/or pleiotropic effects on the transcriptome, making it challenging to determine the underlying cellular and molecular mechanisms that contribute to disease pathogenesis. Understanding how splicing misregulation as well as alterations of mRNA stability and localization impact the activity and function of neuronal proteins is fundamental to addressing neurodevelopmental defects and synaptic dysfunction in disease. Here we highlight recent exciting studies that use high-throughput transcriptomic analysis and advanced genetic, cell biological, and imaging approaches to dissect the role of disease-linked RNA-binding proteins on different RNA processing steps. We focus specifically on efforts to elucidate the functional consequences of aberrant RNA processing on neuronal morphology, synaptic activity and plasticity in development and disease. We also consider new areas of investigation that will elucidate the molecular mechanisms RNA-binding proteins use to achieve spatiotemporal control of gene expression for neuronal homeostasis and plasticity.
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Affiliation(s)
- Shavanie Prashad
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA
| | - Pallavi P Gopal
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Yale Center for RNA Science and Medicine, Yale University School of Medicine, Yale University, New Haven, CT, USA
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33
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Lennox AL, Hoye ML, Jiang R, Johnson-Kerner BL, Suit LA, Venkataramanan S, Sheehan CJ, Alsina FC, Fregeau B, Aldinger KA, Moey C, Lobach I, Afenjar A, Babovic-Vuksanovic D, Bézieau S, Blackburn PR, Bunt J, Burglen L, Campeau PM, Charles P, Chung BHY, Cogné B, Curry C, D'Agostino MD, Di Donato N, Faivre L, Héron D, Innes AM, Isidor B, Keren B, Kimball A, Klee EW, Kuentz P, Küry S, Martin-Coignard D, Mirzaa G, Mignot C, Miyake N, Matsumoto N, Fujita A, Nava C, Nizon M, Rodriguez D, Blok LS, Thauvin-Robinet C, Thevenon J, Vincent M, Ziegler A, Dobyns W, Richards LJ, Barkovich AJ, Floor SN, Silver DL, Sherr EH. Pathogenic DDX3X Mutations Impair RNA Metabolism and Neurogenesis during Fetal Cortical Development. Neuron 2020; 106:404-420.e8. [PMID: 32135084 PMCID: PMC7331285 DOI: 10.1016/j.neuron.2020.01.042] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 11/05/2019] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
De novo germline mutations in the RNA helicase DDX3X account for 1%-3% of unexplained intellectual disability (ID) cases in females and are associated with autism, brain malformations, and epilepsy. Yet, the developmental and molecular mechanisms by which DDX3X mutations impair brain function are unknown. Here, we use human and mouse genetics and cell biological and biochemical approaches to elucidate mechanisms by which pathogenic DDX3X variants disrupt brain development. We report the largest clinical cohort to date with DDX3X mutations (n = 107), demonstrating a striking correlation between recurrent dominant missense mutations, polymicrogyria, and the most severe clinical outcomes. We show that Ddx3x controls cortical development by regulating neuron generation. Severe DDX3X missense mutations profoundly disrupt RNA helicase activity, induce ectopic RNA-protein granules in neural progenitors and neurons, and impair translation. Together, these results uncover key mechanisms underlying DDX3X syndrome and highlight aberrant RNA metabolism in the pathogenesis of neurodevelopmental disease.
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Affiliation(s)
- Ashley L Lennox
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Mariah L Hoye
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ruiji Jiang
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | - Lindsey A Suit
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Srivats Venkataramanan
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Charles J Sheehan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Fernando C Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Brieana Fregeau
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kimberly A Aldinger
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ching Moey
- The University of Queensland, Queensland Brain Institute, Brisbane, QLD 4072, Australia
| | - Iryna Lobach
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Alexandra Afenjar
- Centre de référence des malformations et maladies congénitales du cervelet et Département de génétique et embryologie médicale, APHP, Sorbonne Université, Hôpital Armand Trousseau, 75012 Paris, France
| | - Dusica Babovic-Vuksanovic
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Stéphane Bézieau
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Patrick R Blackburn
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA; Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Jens Bunt
- The University of Queensland, Queensland Brain Institute, Brisbane, QLD 4072, Australia
| | - Lydie Burglen
- Centre de référence des malformations et maladies congénitales du cervelet et Département de génétique et embryologie médicale, APHP, Sorbonne Université, Hôpital Armand Trousseau, 75012 Paris, France
| | - Philippe M Campeau
- Department of Pediatrics, University of Montreal and CHU Sainte-Justine, Montreal, QC, Canada
| | - Perrine Charles
- Département de Génétique, Centre de Référence Déficiences Intellectuelles de Causes Rares, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, APHP, Sorbonne Université, Paris, France
| | - Brian H Y Chung
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Benjamin Cogné
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Cynthia Curry
- Genetic Medicine, University of California San Francisco/Fresno, Fresno, CA 93701, USA
| | - Maria Daniela D'Agostino
- Division of Medical Genetics, Departments of Specialized Medicine and Human Genetics, McGill University, Montreal, QC, Canada
| | | | - Laurence Faivre
- Centre de référence Anomalies du Développement et Syndromes Malformatifs, INSERM UMR 1231 GAD, CHU de Dijon et Université de Bourgogne, Dijon, France
| | - Delphine Héron
- APHP, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - A Micheil Innes
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Boris Keren
- APHP, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Amy Kimball
- Harvey Institute of Human Genetics, Greater Baltimore Medical Center, Baltimore, MD, USA
| | - Eric W Klee
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Paul Kuentz
- UMR-INSERM 1231 GAD, Génétique des Anomalies du développement, Université de Bourgogne Franche-Comté, Dijon, France
| | - Sébastien Küry
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | | | - Ghayda Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington, Seattle, WA 98101, USA
| | - Cyril Mignot
- Département de Génétique, Centre de Référence Déficiences Intellectuelles de Causes Rares, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, APHP, Sorbonne Université, Paris, France
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Caroline Nava
- APHP, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Mathilde Nizon
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | - Diana Rodriguez
- Centre de Référence Neurogénétique & Service de Neurologie Pédiatrique, APHP, Sorbonne Université, Hôpital Armand Trousseau, 75012 Paris, France
| | - Lot Snijders Blok
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands
| | - Christel Thauvin-Robinet
- Centre de référence Déficience Intellectuelle, INSERM UMR 1231 GAD, CHU de Dijon et Université de Bourgogne, Dijon, France
| | - Julien Thevenon
- Centre de référence Anomalies du Développement et Syndromes Malformatifs, INSERM UMR 1231 GAD, CHU de Dijon et Université de Bourgogne, Dijon, France
| | - Marie Vincent
- Service de Génétique Médicale, CHU Nantes, 9 quai Moncousu, 44093 Nantes Cedex 1, France; Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000 Nantes, France
| | | | - William Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Departments of Pediatrics and Neurology, University of Washington, Seattle, WA 98101, USA
| | - Linda J Richards
- The University of Queensland, Queensland Brain Institute, Brisbane, QLD 4072, Australia; The University of Queensland, School of Biomedical Sciences, Brisbane 4072, QLD, Australia
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA; Helen Diller Family Comprehensive Cancer Center, San Francisco, CA 94158, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences, Duke University, Durham, NC 27710, USA.
| | - Elliott H Sherr
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA; Institute of Human Genetics and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA.
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34
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Ji Z, Li H, Yang Z, Huang X, Ke X, Ma S, Lin Z, Lu Y, Zhang M. Kibra Modulates Learning and Memory via Binding to Dendrin. Cell Rep 2020; 26:2064-2077.e7. [PMID: 30784589 DOI: 10.1016/j.celrep.2019.01.097] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/08/2019] [Accepted: 01/25/2019] [Indexed: 10/27/2022] Open
Abstract
Kibra is a synaptic scaffold protein regulating learning and memory. Alterations of Kibra-encoding gene WWC1 cause various neuronal disorders, including Alzheimer's disease and Tourette syndrome. However, the molecular mechanism underlying Kibra's function in neurons is poorly understood. Here we discover that Kibra, via its N-terminal WW12 tandem domains, binds to a postsynaptic density enriched protein, Dendrin, with a nanomolar dissociation constant. On the basis of the structure of Kibra WW12 in complex with Dendrin PY motifs, we developed a potent peptide inhibitor capable of specifically blocking the binding between Kibra and Dendrin in neurons. Systematic administration of the inhibitory peptide attenuated excitatory synaptic transmission, completely blocked long-term potentiation induction, and impaired spatial learning and memory. A Kibra mutation found in Tourette syndrome patients causes defects in binding to Dendrin. Thus, Kibra can modulate spatial learning and memory via binding to Dendrin.
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Affiliation(s)
- Zeyang Ji
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hao Li
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhou Yang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xian Huang
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiao Ke
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sehui Ma
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhijie Lin
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - Youming Lu
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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35
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Babinchak WM, Surewicz WK. Liquid-Liquid Phase Separation and Its Mechanistic Role in Pathological Protein Aggregation. J Mol Biol 2020; 432:1910-1925. [PMID: 32169484 DOI: 10.1016/j.jmb.2020.03.004] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 12/14/2022]
Abstract
Liquid-liquid phase separation (LLPS) of proteins underlies the formation of membrane-less organelles. While it has been recognized for some time that these organelles are of key importance for normal cellular functions, a growing number of recent observations indicate that LLPS may also play a role in disease. In particular, numerous proteins that form toxic aggregates in neurodegenerative diseases, such as amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and Alzheimer's disease, were found to be highly prone to phase separation, suggesting that there might be a strong link between LLPS and the pathogenic process in these disorders. This review aims to assess the molecular basis of this link through exploration of the intermolecular interactions that underlie LLPS and aggregation and the underlying mechanisms facilitating maturation of liquid droplets into more stable assemblies, including so-called labile fibrils, hydrogels, and pathological amyloids. Recent insights into the structural basis of labile fibrils and potential mechanisms by which these relatively unstable structures could transition into more stable pathogenic amyloids are also discussed. Finally, this review explores how the environment of liquid droplets could modulate protein aggregation by altering kinetics of protein self-association, affecting folding of protein monomers, or changing aggregation pathways.
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Affiliation(s)
- W Michael Babinchak
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Witold K Surewicz
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA.
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36
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Wu H, Zhou J, Zhu T, Cohen I, Dictenberg J. A kinesin adapter directly mediates dendritic mRNA localization during neural development in mice. J Biol Chem 2020; 295:6605-6628. [PMID: 32111743 DOI: 10.1074/jbc.ra118.005616] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 08/19/2019] [Indexed: 11/06/2022] Open
Abstract
Motor protein-based active transport is essential for mRNA localization and local translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased yeast two-hybrid screen for interactions between murine RNA-binding proteins (RBPs) and motor proteins, here we identified protein interaction with APP tail-1 (PAT1) as a potential direct adapter between zipcode-binding protein 1 (ZBP1, a β-actin RBP) and the kinesin-I motor complex. The amino acid sequence of mouse PAT1 is similar to that of the kinesin light chain (KLC), and we found that PAT1 binds to KLC directly. Studying PAT1 in mouse primary hippocampal neuronal cultures from both sexes and using structured illumination microscopic imaging of these neurons, we observed that brain-derived neurotrophic factor (BDNF) enhances co-localization of dendritic ZBP1 and PAT1 within granules that also contain kinesin-I. PAT1 is essential for BDNF-stimulated neuronal growth cone development and dendritic protrusion formation, and we noted that ZBP1 and PAT1 co-locate along with β-actin mRNA in actively transported granules in living neurons. Acute disruption of the PAT1-ZBP1 interaction in neurons with PAT1 siRNA or a dominant-negative ZBP1 construct diminished localization of β-actin mRNA but not of Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) mRNA in dendrites. The aberrant β-actin mRNA localization resulted in abnormal dendritic protrusions and growth cone dynamics. These results suggest a critical role for PAT1 in BDNF-induced β-actin mRNA transport during postnatal development and reveal a new molecular mechanism for mRNA localization in vertebrates.
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Affiliation(s)
- Hao Wu
- Department of Biological Sciences, Hunter College, City University of New York, New York, New York 10065 .,Biology Program, Graduate School and University Center, City University of New York, New York, New York 10016
| | - Jing Zhou
- Biology Program, Graduate School and University Center, City University of New York, New York, New York 10016.,Biology Department, Lehman College, City University of New York, Bronx, New York 10468
| | - Tianhui Zhu
- Department of Biological Sciences, Hunter College, City University of New York, New York, New York 10065.,Biology Program, Graduate School and University Center, City University of New York, New York, New York 10016
| | - Ivan Cohen
- Department of Biological Sciences, Hunter College, City University of New York, New York, New York 10065
| | - Jason Dictenberg
- Cell Biology, State University of New York Downstate, Brooklyn, New York 11226 .,Biotechnology Incubator, AccelBio, Brooklyn, New York 11226
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37
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Pushpalatha KV, Besse F. Local Translation in Axons: When Membraneless RNP Granules Meet Membrane-Bound Organelles. Front Mol Biosci 2019; 6:129. [PMID: 31824961 PMCID: PMC6882739 DOI: 10.3389/fmolb.2019.00129] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/06/2019] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cell compartmentalization relies on long-known membrane-delimited organelles, as well as on more recently discovered membraneless macromolecular condensates. How these two types of organelles interact to regulate cellular functions is still largely unclear. In this review, we highlight how membraneless ribonucleoprotein (RNP) organelles, enriched in RNAs and associated regulatory proteins, cooperate with membrane-bound organelles for tight spatio-temporal control of gene expression in the axons of neuronal cells. Specifically, we present recent evidence that motile membrane-bound organelles are used as vehicles by RNP cargoes, promoting the long-range transport of mRNA molecules to distal axons. As demonstrated by recent work, membrane-bound organelles also promote local protein synthesis, by serving as platforms for the local translation of mRNAs recruited to their outer surface. Furthermore, dynamic and specific association between RNP cargoes and membrane-bound organelles is mediated by bi-partite adapter molecules that interact with both types of organelles selectively, in a regulated-manner. Maintaining such a dynamic interplay is critical, as alterations in this process are linked to neurodegenerative diseases. Together, emerging studies thus point to the coordination of membrane-bound and membraneless organelles as an organizing principle underlying local cellular responses.
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Affiliation(s)
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biology Valrose, Nice, France
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38
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Sechi S, Frappaolo A, Karimpour-Ghahnavieh A, Gottardo M, Burla R, Di Francesco L, Szafer-Glusman E, Schininà E, Fuller MT, Saggio I, Riparbelli MG, Callaini G, Giansanti MG. Drosophila Doublefault protein coordinates multiple events during male meiosis by controlling mRNA translation. Development 2019; 146:dev.183053. [PMID: 31645358 DOI: 10.1242/dev.183053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/21/2019] [Indexed: 12/31/2022]
Abstract
During the extended prophase of Drosophila gametogenesis, spermatocytes undergo robust gene transcription and store many transcripts in the cytoplasm in a repressed state, until translational activation of select mRNAs in later steps of spermatogenesis. Here, we characterize the Drosophila Doublefault (Dbf) protein as a C2H2 zinc-finger protein, primarily expressed in testes, that is required for normal meiotic division and spermiogenesis. Loss of Dbf causes premature centriole disengagement and affects spindle structure, chromosome segregation and cytokinesis. We show that Dbf interacts with the RNA-binding protein Syncrip/hnRNPQ, a key regulator of localized translation in Drosophila We propose that the pleiotropic effects of dbf loss-of-function mutants are associated with the requirement of dbf function for translation of specific transcripts in spermatocytes. In agreement with this hypothesis, Dbf protein binds cyclin B mRNA and is essential for translation of cyclin B in mature spermatocytes.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Marco Gottardo
- Dipartimento di Scienze della Vita, Università di Siena, 53100 Siena, Italy
| | - Romina Burla
- Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Laura Di Francesco
- Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Edith Szafer-Glusman
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, CA 94305-5329, USA
| | - Eugenia Schininà
- Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Margaret T Fuller
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, CA 94305-5329, USA
| | - Isabella Saggio
- Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | | | - Giuliano Callaini
- Dipartimento di Biotecnologie Mediche, Università di Siena, 53100 Siena, Italy
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy
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39
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Sabharwal V, Koushika SP. Crowd Control: Effects of Physical Crowding on Cargo Movement in Healthy and Diseased Neurons. Front Cell Neurosci 2019; 13:470. [PMID: 31708745 PMCID: PMC6823667 DOI: 10.3389/fncel.2019.00470] [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: 06/16/2019] [Accepted: 10/02/2019] [Indexed: 01/22/2023] Open
Abstract
High concentration of cytoskeletal filaments, organelles, and proteins along with the space constraints due to the axon's narrow geometry lead inevitably to intracellular physical crowding along the axon of a neuron. Local cargo movement is essential for maintaining steady cargo transport in the axon, and this may be impeded by physical crowding. Molecular motors that mediate active transport share movement mechanisms that allow them to bypass physical crowding present on microtubule tracks. Many neurodegenerative diseases, irrespective of how they are initiated, show increased physical crowding owing to the greater number of stalled organelles and structural changes associated with the cytoskeleton. Increased physical crowding may be a significant factor in slowing cargo transport to synapses, contributing to disease progression and culminating in the dying back of the neuronal process. This review explores the idea that physical crowding can impede cargo movement along the neuronal process. We examine the sources of physical crowding and strategies used by molecular motors that might enable cargo to circumvent physically crowded locations. Finally, we describe sub-cellular changes in neurodegenerative diseases that may alter physical crowding and discuss the implications of such changes on cargo movement.
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Affiliation(s)
| | - Sandhya P. Koushika
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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40
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Langille JJ, Ginzberg K, Sossin WS. Polysomes identified by live imaging of nascent peptides are stalled in hippocampal and cortical neurites. ACTA ACUST UNITED AC 2019; 26:351-362. [PMID: 31416908 PMCID: PMC6699411 DOI: 10.1101/lm.049965.119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/10/2019] [Indexed: 12/18/2022]
Abstract
In neurons, mRNAs can be repressed postinitiation and assembled into granules enabling the transport and later, regulated reactivation of the paused mRNAs. It has been suggested that a large percentage of transcripts in neuronal processes are stored in these stalled polysomes. Given this, it is predicted that nascent peptides should be abundant in these granules. Nascent peptides can be visualized in real time by the SunTag system. Using this system, we observe nascent peptides in neuronal processes that are resistant to runoff with the initiation inhibitor homoharringtonin (HHT) and to release by puromycin, properties expected from RNA granules consisting of stalled polysomes. In contrast, nascent peptides in nonneuronal cells and neuronal cell bodies were not resistant to HHT or puromycin. Stalled polysomes can also be visualized after runoff with ribopuromycylation and the RNA granules imaged with ribopuromycylation were the same as those with SunTag visualized nascent peptides. Accordingly, the ribopuromycylated puncta in neuronal dendrites were also resistant to puromycin. Thus, the SunTag technique corroborates in situ evidence of stalled polysomes and will allow for the live examination of these translational structures as a mechanism for mRNA transport and regulated protein synthesis.
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Affiliation(s)
- Jesse J Langille
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
| | - Keren Ginzberg
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
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41
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Formicola N, Vijayakumar J, Besse F. Neuronal ribonucleoprotein granules: Dynamic sensors of localized signals. Traffic 2019; 20:639-649. [PMID: 31206920 DOI: 10.1111/tra.12672] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/03/2019] [Accepted: 06/11/2019] [Indexed: 12/14/2022]
Abstract
Membrane-less organelles, because of their capacity to dynamically, selectively and reversibly concentrate molecules, are very well adapted for local information processing and rapid response to environmental fluctuations. These features are particularly important in the context of neuronal cells, where synapse-specific activation, or localized extracellular cues, induce signaling events restricted to specialized axonal or dendritic subcompartments. Neuronal ribonucleoprotein (RNP) particles, or granules, are nonmembrane bound macromolecular condensates that concentrate specific sets of mRNAs and regulatory proteins, promoting their long-distance transport to axons or dendrites. Neuronal RNP granules also have a dual function in regulating the translation of associated mRNAs: while preventing mRNA translation at rest, they fuel local protein synthesis upon activation. As revealed by recent work, rapid and reversible switches between these two functional modes are triggered by modifications of the networks of interactions underlying RNP granule assembly. Such flexible properties also come with a cost, as neuronal RNP granules are prone to transition into pathological aggregates in response to mutations, aging, or cellular stresses, further emphasizing the need to better understand the mechanistic principles governing their dynamic assembly and regulation in living systems.
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42
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Cioni JM, Wong HHW, Bressan D, Kodama L, Harris WA, Holt CE. Axon-Axon Interactions Regulate Topographic Optic Tract Sorting via CYFIP2-Dependent WAVE Complex Function. Neuron 2019. [PMID: 29518358 PMCID: PMC5855093 DOI: 10.1016/j.neuron.2018.01.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The axons of retinal ganglion cells (RGCs) are topographically sorted before they arrive at the optic tectum. This pre-target sorting, typical of axon tracts throughout the brain, is poorly understood. Here, we show that cytoplasmic FMR1-interacting proteins (CYFIPs) fulfill non-redundant functions in RGCs, with CYFIP1 mediating axon growth and CYFIP2 specifically involved in axon sorting. We find that CYFIP2 mediates homotypic and heterotypic contact-triggered fasciculation and repulsion responses between dorsal and ventral axons. CYFIP2 associates with transporting ribonucleoprotein particles in axons and regulates translation. Axon-axon contact stimulates CYFIP2 to move into growth cones where it joins the actin nucleating WAVE regulatory complex (WRC) in the periphery and regulates actin remodeling and filopodial dynamics. CYFIP2’s function in axon sorting is mediated by its binding to the WRC but not its translational regulation. Together, these findings uncover CYFIP2 as a key regulatory link between axon-axon interactions, filopodial dynamics, and optic tract sorting. CYFIP1 and CYFIP2 serve non-redundant functions in retinal axon growth and guidance CYFIP2 regulates growth cone filopodial dynamics and axon-axon responses CYFIP2 interacts with RNPs and the WRC in distinct cellular compartments Axon sorting is mediated by CYFIP2’s interaction with the WRC
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Affiliation(s)
- Jean-Michel Cioni
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Hovy Ho-Wai Wong
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Dario Bressan
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Lay Kodama
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - William A Harris
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Christine E Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK.
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43
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Afonso P, De Luca P, Carvalho RS, Cortes L, Pinheiro P, Oliveiros B, Almeida RD, Mele M, Duarte CB. BDNF increases synaptic NMDA receptor abundance by enhancing the local translation of Pyk2 in cultured hippocampal neurons. Sci Signal 2019; 12:12/586/eaav3577. [PMID: 31213568 DOI: 10.1126/scisignal.aav3577] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of brain-derived neurotrophic factor (BDNF) in long-term synaptic potentiation (LTP) are thought to underlie learning and memory formation and are partly mediated by local protein synthesis. Here, we investigated the mechanisms that mediate BDNF-induced alterations in the synaptic proteome that are coupled to synaptic strengthening. BDNF induced the synaptic accumulation of GluN2B-containing NMDA receptors (NMDARs) and increased the amplitude of NMDAR-mediated miniature excitatory postsynaptic currents (mEPSCs) in cultured rat hippocampal neurons by a mechanism requiring activation of the protein tyrosine kinase Pyk2 and dependent on cellular protein synthesis. Single-particle tracking using quantum dot imaging revealed that the increase in the abundance of synaptic NMDAR currents correlated with their enhanced stability in the synaptic compartment. Furthermore, BDNF increased the local synthesis of Pyk2 at the synapse, and the observed increase in Pyk2 protein abundance along dendrites of cultured hippocampal neurons was mediated by a mechanism dependent on the ribonucleoprotein hnRNP K, which bound to Pyk2 mRNA and dissociated from it upon BDNF application. Knocking down hnRNP K reduced the BDNF-induced synaptic synthesis of Pyk2 protein, whereas its overexpression enhanced it. Together, these findings indicate that hnRNP K mediates the synaptic distribution of Pyk2 synthesis, and hence the synaptic incorporation of GluN2B-containing NMDARs, induced by BDNF, which may affect LTP and synaptic plasticity.
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Affiliation(s)
- Pedro Afonso
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Pasqualino De Luca
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Rafael S Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Luísa Cortes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Paulo Pinheiro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Barbara Oliveiros
- Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.,Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ramiro D Almeida
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Health Sciences Program, Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal. .,Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
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44
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Chung HW, Weng JC, King CE, Chuang CF, Chow WY, Chang YC. BDNF elevates the axonal levels of hnRNPs Q and R in cultured rat cortical neurons. Mol Cell Neurosci 2019; 98:97-108. [PMID: 31202892 DOI: 10.1016/j.mcn.2019.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 05/08/2019] [Accepted: 06/12/2019] [Indexed: 11/17/2022] Open
Abstract
Local translation plays important roles in the maintenance and various functions of axons, and dysfunctions of local translation in axons are implicated in various neurological diseases. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA binding proteins with multiple functions in RNA metabolism. Here, we identified 20 hnRNPs in the axons of cultured rat cortical neurons by interrogating published axon mass spectrometric databases with rat protein databases. Among those identified in axons are highly related hnRNPs Q and R. RT-PCR analysis indicated that axons also contained low levels of hnRNPs Q and R mRNAs. We further found that BDNF treatments raised the levels of hnRNPs Q and R proteins in whole neurons and axons. BDNF also increased the level of poly(A) RNA as well as the proportion of poly(A) RNA granules containing hnRNPs Q and R in the axon. However, following severing the connection between the cell bodies and axons, BDNF did not affect the levels of hnRNPs Q and R, the content of poly(A) RNA, or the colocalization of poly(A) RNA and hnRNPs Q and R in the axon any more, although BDNF still stimulated the local translation in severed axons as it did in intact axons. The results are consistent with that BDNF enhances the axonal transport of RNA granules. The results further suggest that hnRNPs Q and R play a role in the mechanism underlying the enhancement of axonal RNA transport by BDNF.
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Affiliation(s)
- Hui-Wen Chung
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan.
| | - Ju-Chen Weng
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu, Taiwan
| | - Chih-En King
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu, Taiwan
| | - Chih-Fan Chuang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan.
| | - Wei-Yuan Chow
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan.
| | - Yen-Chung Chang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu, Taiwan.
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45
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Lee SH, Mayr C. Gain of Additional BIRC3 Protein Functions through 3'-UTR-Mediated Protein Complex Formation. Mol Cell 2019; 74:701-712.e9. [PMID: 30948266 DOI: 10.1016/j.molcel.2019.03.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 01/08/2019] [Accepted: 03/04/2019] [Indexed: 12/13/2022]
Abstract
Alternative 3' untranslated regions (3' UTRs) are widespread, but their functional roles are largely unknown. We investigated the function of the long BIRC3 3' UTR, which is upregulated in leukemia. The 3' UTR does not regulate BIRC3 protein localization or abundance but is required for CXCR4-mediated B cell migration. We established an experimental pipeline to study the mechanism of regulation and used mass spectrometry to identify BIRC3 protein interactors. In addition to 3'-UTR-independent interactors involved in known BIRC3 functions, we detected interactors that bind only to BIRC3 protein encoded from the mRNA with the long 3' UTR. They regulate several functions, including CXCR4 trafficking. We further identified RNA-binding proteins differentially bound to the alternative 3' UTRs and found that cooperative binding of Staufen and HuR mediates 3'-UTR-dependent complex formation. We show that the long 3' UTR is required for the formation of specific protein complexes that enable additional functions of BIRC3 protein beyond its 3'-UTR-independent functions.
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Affiliation(s)
- Shih-Han Lee
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Christine Mayr
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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46
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Pazo A, Pérez-González A, Oliveros JC, Huarte M, Chavez JP, Nieto A. hCLE/RTRAF-HSPC117-DDX1-FAM98B: A New Cap-Binding Complex That Activates mRNA Translation. Front Physiol 2019; 10:92. [PMID: 30833903 PMCID: PMC6388641 DOI: 10.3389/fphys.2019.00092] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/25/2019] [Indexed: 11/29/2022] Open
Abstract
hCLE/C14orf166/RTRAF, DDX1, and HSPC117 are components of cytoplasmic mRNA-transporting granules kinesin-associated in dendrites. They have also been found in cytoplasmic ribosome-containing RNA granules that transport specific mRNAs halted for translation until specific neuronal signals renders them accessible to the translation machinery. hCLE associates to DDX1, HSPC117, and FAM98B in HEK293T cells and all four proteins bind to cap analog-containing resins. Competition and elution experiments indicate that binding of hCLE complex to cap resins is independent of eIF4E; the cap-binding factor needed for translation. Purified hCLE free of its associated proteins binds cap with low affinity suggesting that its interacting proteins modulate its cap association. hCLE silencing reduces hCLE accumulation and that of its interacting proteins and decreases mRNA translation. hCLE-associated RNAs have been isolated and sequenced; RNAs involved in mRNA translation are specifically associated. The data suggest that RNA granules may co-transport RNAs encoding proteins involved in specific functions together with RNAs that encode proteins needed for the translation of these specific RNAs and indicate an important role for hCLE modulating mRNA translation.
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Affiliation(s)
- Alejandra Pazo
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Alicia Pérez-González
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | | | - Maite Huarte
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Juan Pablo Chavez
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Amelia Nieto
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
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47
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Neriec N, Percipalle P. Sorting mRNA Molecules for Cytoplasmic Transport and Localization. Front Genet 2018; 9:510. [PMID: 30459808 PMCID: PMC6232293 DOI: 10.3389/fgene.2018.00510] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/12/2018] [Indexed: 01/03/2023] Open
Abstract
In eukaryotic cells, gene expression is highly regulated at many layers. Nascent RNA molecules are assembled into ribonucleoprotein complexes that are then released into the nucleoplasmic milieu and transferred to the nuclear pore complex for nuclear export. RNAs are then either translated or transported to the cellular periphery. Emerging evidence indicates that RNA-binding proteins play an essential role throughout RNA biogenesis, from the gene to polyribosomes. However, the sorting mechanisms that regulate whether an RNA molecule is immediately translated or sent to specialized locations for translation are unclear. This question is highly relevant during development and differentiation when cells acquire a specific identity. Here, we focus on the RNA-binding properties of heterogeneous nuclear ribonucleoproteins (hnRNPs) and how these mechanisms are believed to play an essential role in RNA trafficking in polarized cells. Further, by focusing on the specific hnRNP protein CBF-A/hnRNPab and its naturally occurring isoforms, we propose a model on how hnRNP proteins are capable of regulating gene expression both spatially and temporally throughout the RNA biogenesis pathway, impacting both healthy and diseased cells.
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Affiliation(s)
- Nathalie Neriec
- Biology Department, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Piergiorgio Percipalle
- Biology Department, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Overexpressed C14orf166 associates with disease progression and poor prognosis in non-small-cell lung cancer. Biosci Rep 2018; 38:BSR20180479. [PMID: 30126850 PMCID: PMC6137245 DOI: 10.1042/bsr20180479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/12/2018] [Accepted: 08/09/2018] [Indexed: 01/05/2023] Open
Abstract
Chromosome 14 ORF 166 (C14orf166), a protein involved in the regulation of RNA transcription and translation, has been reported to possess the potency to promote tumorigenesis; however, the role of C14orf166 in non-small-cell lung cancer (NSCLC) remains unknown. The purpose of the present study was to assess C14orf166 expression and its clinical significance in NSCLC. Immunohistochemical staining, quantitative real-time PCR (qRT-PCR), and Western blotting were used to detect the C14orf166 protein and mRNA expression levels in NSCLC tissues compared with adjacent normal tissues, as well as in NSCLC cells lines compared with normal human bronchial epithelial cells (HBE). Then, the correlations between the C14orf166 expression levels and the clinicopathological features of NSCLC were analyzed. Additionally, the Cox proportional hazard model was used to evaluate the prognostic significance of C14orf166. We found that C14orf166 expression increased in carcinoma tissues compared with their adjacent normal tissues at the protein (P<0.001) and mRNA levels (P<0.001). High expression of C14orf166 was significantly associated with the T stage (P=0.006), lymph node metastasis (P=0.001), advanced TNM stage (P<0.001), and chemotherapy (P<0.001). Moreover, according to the survival analysis, patients with overexpressed C14orf166 were inclined to experience a shorter overall survival and disease-free survival time (P<0.001). Multivariate COX analysis implied that C14orf166 was an independent prognostic biomarker. Taken together, our findings indicate that the overexpression of C14orf166 may contribute to the disease progression of NSCLC, represent a novel prognostic predictor and help high-risk patients make better decisions for subsequent therapy.
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Samson J, Cronin S, Dean K. BC200 (BCYRN1) - The shortest, long, non-coding RNA associated with cancer. Noncoding RNA Res 2018; 3:131-143. [PMID: 30175286 PMCID: PMC6114260 DOI: 10.1016/j.ncrna.2018.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 12/22/2022] Open
Abstract
With the discovery that the level of RNA synthesis in human cells far exceeds what is required to express protein-coding genes, there has been a concerted scientific effort to identify, catalogue and uncover the biological functions of the non-coding transcriptome. Long, non-coding RNAs (lncRNAs) are a diverse group of RNAs with equally wide-ranging biological roles in the cell. An increasing number of studies have reported alterations in the expression of lncRNAs in various cancers, although unravelling how they contribute specifically to the disease is a bigger challenge. Originally described as a brain-specific, non-coding RNA, BC200 (BCYRN1) is a 200-nucleotide, predominantly cytoplasmic lncRNA that has been linked to neurodegenerative disease and several types of cancer. Here we summarise what is known about BC200, primarily from studies in neuronal systems, before turning to a review of recent work that aims to understand how this lncRNA contributes to cancer initiation, progression and metastasis, along with its possible clinical utility as a biomarker or therapeutic target.
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Affiliation(s)
| | | | - K. Dean
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
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50
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Distal Axonal Proteins and Their Related MiRNAs in Cultured Cortical Neurons. Mol Neurobiol 2018; 56:2703-2713. [PMID: 30054858 DOI: 10.1007/s12035-018-1266-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/18/2018] [Indexed: 12/15/2022]
Abstract
Proteins and microRNAs (miRNAs) within the axon locally regulate axonal development. However, protein profiles of distal axons of cortical neurons have not been fully investigated. In particular, networks of genes encoding axonal proteins and their related miRNAs in sub compartments of neurons such as axons remain unknown. Using embryonic cortical neurons cultured in a microfluidic device and proteomic approaches, we found that distal axons contain 883 proteins. Bioinformatics analysis revealed that 94 out of these 883 proteins are related to regulating axonal growth. Of the 94 genes encoding these proteins, there were 56 candidate genes that can be putatively targeted by axon-enriched 62 miRNAs with 8mer sites that exactly match these target genes. Among them, we validated 11 proteins and 11 miRNAs, by means of western blot and RT-PCR, respectively. Treatment of distal axons with chondroitin sulfate proteoglycans (CSPGs) that inhibit axonal growth elevated miR-133b, -203a, -29a, and -92a, which were associated with reduced protein level of AKT, MTOR, PI3K, DPYSL2, MAP1B, and PPP2CA. In contrast, reduction of miR-128, -15b, -195, -26b, -34b, -376b, and -381 by CSPGs was accompanied by increased EZR, KIF5A, DCX, GSK3B, and ROCK2 proteins. In silico pathway analysis revealed an interconnected network of these miRNAs and protein coding genes that is highly related to regulating axonal growth. Our data provide new insights into networks of miRNAs and their related proteins in distal axons in mediating axonal growth.
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