1
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Kuc CA, Brott JT, Thorpe HHA, Smart A, Vessey JP. Staufen 1 is expressed by neural precursor cells in the developing murine cortex but is dispensable for NPC self-renewal and neuronal differentiation in vitro. Brain Res 2021; 1773:147700. [PMID: 34678304 DOI: 10.1016/j.brainres.2021.147700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/14/2021] [Accepted: 10/17/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Proper development of the cerebral cortex relies on asymmetric divisions of neural precursor cells (NPCs) to produce a recurring NPC and a differentiated neuron. Asymmetric divisions are promoted by the differential localization of cell-fate determinants, such as mRNA, between daughter cells. Staufen 1 (Stau1) is an RNA-binding protein known to localize mRNA in mature hippocampal neurons. Its expression pattern and role in the developing mammalian cortex remains unknown. RESULTS Both stau1 mRNA and Stau1 protein were found to be expressed in all cells of the developing murine cortex. Stau1 protein expression was characterized spatially and temporally throughout cortical development and found to be present in all stages investigated. We observed expression in the nucleus, cytoplasm and distal processes of both NPCs and newly born neurons and found it to shuttle between the nucleus and the cytoplasm. Upon shRNA-mediated knock-down of Stau1 in primary cultures of the developing cortex, we did not observe any phenotype in NPCs. They were able to both self-renew and generate neurons in the absence of Stau1 expression. CONCLUSIONS We propose that Stau1 is either dispensable for the development of the cerebral cortex or that its paralogue, Stau2, is able to compensate for its loss.
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Affiliation(s)
- C A Kuc
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, Canada
| | - J T Brott
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, Canada
| | - H H A Thorpe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, Canada
| | - A Smart
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, Canada
| | - J P Vessey
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, Canada.
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2
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Chowdhury R, Wang Y, Campbell M, Goderie SK, Doyle F, Tenenbaum SA, Kusek G, Kiehl TR, Ansari SA, Boles NC, Temple S. STAU2 binds a complex RNA cargo that changes temporally with production of diverse intermediate progenitor cells during mouse corticogenesis. Development 2021; 148:271165. [PMID: 34345913 DOI: 10.1242/dev.199376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 07/05/2021] [Indexed: 12/18/2022]
Abstract
STAU2 is a double-stranded RNA-binding protein enriched in the nervous system. During asymmetric divisions in the developing mouse cortex, STAU2 preferentially distributes into the intermediate progenitor cell (IPC), delivering RNA molecules that can impact IPC behavior. Corticogenesis occurs on a precise time schedule, raising the hypothesis that the cargo STAU2 delivers into IPCs changes over time. To test this, we combine RNA-immunoprecipitation with sequencing (RIP-seq) over four stages of mouse cortical development, generating a comprehensive cargo profile for STAU2. A subset of the cargo was 'stable', present at all stages, and involved in chromosome organization, macromolecule localization, translation and DNA repair. Another subset was 'dynamic', changing with cortical stage, and involved in neurogenesis, cell projection organization, neurite outgrowth, and included cortical layer markers. Notably, the dynamic STAU2 cargo included determinants of IPC versus neuronal fates and genes contributing to abnormal corticogenesis. Knockdown of one STAU2 target, Taf13, previously linked to microcephaly and impaired myelination, reduced oligodendrogenesis in vitro. We conclude that STAU2 contributes to the timing of corticogenesis by binding and delivering complex and temporally regulated RNA cargo into IPCs.
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Affiliation(s)
- Rebecca Chowdhury
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Yue Wang
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Melissa Campbell
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Susan K Goderie
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Francis Doyle
- Nanobioscience Constellation, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Scott A Tenenbaum
- Nanobioscience Constellation, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Gretchen Kusek
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Thomas R Kiehl
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Nathan C Boles
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Sally Temple
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
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3
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Bonnet-Magnaval F, DesGroseillers L. The Staufen1-dependent cell cycle regulon or how a misregulated RNA-binding protein leads to cancer. Biol Rev Camb Philos Soc 2021; 96:2192-2208. [PMID: 34018319 DOI: 10.1111/brv.12749] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022]
Abstract
In recent years, an increasing number of reports have linked the RNA-binding protein Staufen1 (STAU1) to the control of cell decision making. In non-transformed cells, STAU1 balances the expression of messenger RNA (mRNA) regulons that regulate differentiation and well-ordered cell division. Misregulation of STAU1 expression and/or functions changes the fragile balance in the expression of pro- and anti-proliferative and apoptotic genes and favours a novel equilibrium that supports cell proliferation and cancer development. The misregulation of STAU1 functions causes multiple coordinated modest effects in the post-transcriptional regulation of many RNA targets that code for cell cycle regulators, leading to dramatic consequences at the cellular level. The new tumorigenic equilibrium in STAU1-mediated gene regulation observed in cancer cells can be further altered by a slight increase in STAU1 expression that favours expression of pro-apoptotic genes and cell death. The STAU1-dependent cell cycle regulon is a good model to study how abnormal expression of an RNA-binding protein promotes cell growth and provides an advantageous selection of malignant cells in the first step of cancer development.
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Affiliation(s)
- Florence Bonnet-Magnaval
- Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Édouard Montpetit, Montréal, QC, H3T 1J4, Canada
| | - Luc DesGroseillers
- Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Édouard Montpetit, Montréal, QC, H3T 1J4, Canada
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4
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Kim ES, Chung CG, Park JH, Ko BS, Park SS, Kim YH, Cha IJ, Kim J, Ha CM, Kim HJ, Lee SB. C9orf72-associated arginine-rich dipeptide repeats induce RNA-dependent nuclear accumulation of Staufen in neurons. Hum Mol Genet 2021; 30:1084-1100. [PMID: 33783499 PMCID: PMC8188407 DOI: 10.1093/hmg/ddab089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/24/2022] Open
Abstract
RNA-binding proteins (RBPs) play essential roles in diverse cellular processes through post-transcriptional regulation of RNAs. The subcellular localization of RBPs is thus under tight control, the breakdown of which is associated with aberrant cytoplasmic accumulation of nuclear RBPs such as TDP-43 and FUS, well-known pathological markers for amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). Here, we report in Drosophila model for ALS/FTD that nuclear accumulation of a cytoplasmic RBP Staufen may be a new pathological feature. We found that in Drosophila C4da neurons expressing PR36, one of the arginine-rich dipeptide repeat proteins (DPRs), Staufen accumulated in the nucleus in Importin- and RNA-dependent manner. Notably, expressing Staufen with exogenous NLS—but not with mutated endogenous NLS—potentiated PR-induced dendritic defect, suggesting that nuclear-accumulated Staufen can enhance PR toxicity. PR36 expression increased Fibrillarin staining in the nucleolus, which was enhanced by heterozygous mutation of stau (stau+/−), a gene that codes Staufen. Furthermore, knockdown of fib, which codes Fibrillarin, exacerbated retinal degeneration mediated by PR toxicity, suggesting that increased amount of Fibrillarin by stau+/− is protective. stau+/− also reduced the amount of PR-induced nuclear-accumulated Staufen and mitigated retinal degeneration and rescued viability of flies expressing PR36. Taken together, our data show that nuclear accumulation of Staufen in neurons may be an important pathological feature contributing to the pathogenesis of ALS/FTD.
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Affiliation(s)
- Eun Seon Kim
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea.,Dementia research group, Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea
| | - Chang Geon Chung
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Jeong Hyang Park
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Byung Su Ko
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Sung Soon Park
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Yoon Ha Kim
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - In Jun Cha
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Jaekwang Kim
- Dementia research group, Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities of Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea
| | - Hyung-Jun Kim
- Dementia research group, Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea.,Dementia research group, Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea
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5
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STAU2 protein level is controlled by caspases and the CHK1 pathway and regulates cell cycle progression in the non-transformed hTERT-RPE1 cells. BMC Mol Cell Biol 2021; 22:16. [PMID: 33663378 PMCID: PMC7934504 DOI: 10.1186/s12860-021-00352-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 02/22/2021] [Indexed: 11/10/2022] Open
Abstract
Background Staufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from the STAU2 gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation. Results CRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism. Conclusions These results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s12860-021-00352-y.
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6
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Bansal P, Madlung J, Schaaf K, Macek B, Bono F. An Interaction Network of RNA-Binding Proteins Involved in Drosophila Oogenesis. Mol Cell Proteomics 2020; 19:1485-1502. [PMID: 32554711 PMCID: PMC8143644 DOI: 10.1074/mcp.ra119.001912] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/26/2020] [Indexed: 12/31/2022] Open
Abstract
During Drosophila oogenesis, the localization and translational regulation of maternal transcripts relies on RNA-binding proteins (RBPs). Many of these RBPs localize several mRNAs and may have additional direct interaction partners to regulate their functions. Using immunoprecipitation from whole Drosophila ovaries coupled to mass spectrometry, we examined protein-protein associations of 6 GFP-tagged RBPs expressed at physiological levels. Analysis of the interaction network and further validation in human cells allowed us to identify 26 previously unknown associations, besides recovering several well characterized interactions. We identified interactions between RBPs and several splicing factors, providing links between nuclear and cytoplasmic events of mRNA regulation. Additionally, components of the translational and RNA decay machineries were selectively co-purified with some baits, suggesting a mechanism for how RBPs may regulate maternal transcripts. Given the evolutionary conservation of the studied RBPs, the interaction network presented here provides the foundation for future functional and structural studies of mRNA localization across metazoans.
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Affiliation(s)
- Prashali Bansal
- Living Systems Institute, University of Exeter, Exeter, UK; Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Johannes Madlung
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, Eberhard Karls University, Tübingen, Germany
| | - Kristina Schaaf
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, Eberhard Karls University, Tübingen, Germany
| | - Fulvia Bono
- Living Systems Institute, University of Exeter, Exeter, UK; Max Planck Institute for Developmental Biology, Tübingen, Germany.
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7
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Visentin S, Cannone G, Doutch J, Harris G, Gleghorn ML, Clifton L, Smith BO, Spagnolo L. A multipronged approach to understanding the form and function of hStaufen protein. RNA (NEW YORK, N.Y.) 2020; 26:265-277. [PMID: 31852734 PMCID: PMC7025507 DOI: 10.1261/rna.072595.119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 12/09/2019] [Indexed: 05/09/2023]
Abstract
Staufen is a dsRNA-binding protein involved in many aspects of RNA regulation, such as mRNA transport, Staufen-mediated mRNA decay and the regulation of mRNA translation. It is a modular protein characterized by the presence of conserved consensus amino acid sequences that fold into double-stranded RNA binding domains (RBDs) as well as degenerated RBDs that are instead involved in protein-protein interactions. The variety of biological processes in which Staufen participates in the cell suggests that this protein associates with many diverse RNA targets, some of which have been identified experimentally. Staufen binding mediates the recruitment of effectors via protein-protein and protein-RNA interactions. The structural determinants of a number of these interactions, as well as the structure of full-length Staufen, remain unknown. Here, we present the first solution structure models for full-length hStaufen155, showing that its domains are arranged as beads-on-a-string connected by flexible linkers. In analogy with other nucleic acid-binding proteins, this could underpin Stau1 functional plasticity.
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Affiliation(s)
- Silvia Visentin
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JQ, United Kingdom
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Didcot OX11 OQX, United Kingdom
| | - Giuseppe Cannone
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JQ, United Kingdom
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - James Doutch
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Didcot OX11 OQX, United Kingdom
| | - Gemma Harris
- Research Complex at Harwell, Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
| | - Michael L Gleghorn
- School of Chemistry and Materials Science, College of Science, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - Luke Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Didcot OX11 OQX, United Kingdom
| | - Brian O Smith
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Laura Spagnolo
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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8
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Heber S, Gáspár I, Tants JN, Günther J, Moya SMF, Janowski R, Ephrussi A, Sattler M, Niessing D. Staufen2-mediated RNA recognition and localization requires combinatorial action of multiple domains. Nat Commun 2019; 10:1659. [PMID: 30971701 PMCID: PMC6477676 DOI: 10.1038/s41467-019-09655-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/20/2019] [Indexed: 11/08/2022] Open
Abstract
Throughout metazoans, Staufen (Stau) proteins are core factors of mRNA localization particles. They consist of three to four double-stranded RNA binding domains (dsRBDs) and a C-terminal dsRBD-like domain. Mouse Staufen2 (mStau2)-like Drosophila Stau (dmStau) contains four dsRBDs. Existing data suggest that only dsRBDs 3-4 are necessary and sufficient for mRNA binding. Here, we show that dsRBDs 1 and 2 of mStau2 bind RNA with similar affinities and kinetics as dsRBDs 3 and 4. While RNA binding by these tandem domains is transient, all four dsRBDs recognize their target RNAs with high stability. Rescue experiments in Drosophila oocytes demonstrate that mStau2 partially rescues dmStau-dependent mRNA localization. In contrast, a rescue with mStau2 bearing RNA-binding mutations in dsRBD1-2 fails, confirming the physiological relevance of our findings. In summary, our data show that the dsRBDs 1-2 play essential roles in the mRNA recognition and function of Stau-family proteins of different species.
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Affiliation(s)
- Simone Heber
- Institute of Pharmaceutical Biotechnology, 89081 Ulm University, Ulm, Germany
- Institute of Structural Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany
| | - Imre Gáspár
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117, Heidelberg, Germany
- Institute of Molecular Biotechnology, 1030, Vienna, Austria
| | - Jan-Niklas Tants
- Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department Chemistry, Technische Universität München, 85747, Garching, Germany
| | - Johannes Günther
- Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department Chemistry, Technische Universität München, 85747, Garching, Germany
| | - Sandra M Fernandez Moya
- Biomedical Center Munich, Department of Cell Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany
| | - Robert Janowski
- Institute of Structural Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117, Heidelberg, Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany
- Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department Chemistry, Technische Universität München, 85747, Garching, Germany
| | - Dierk Niessing
- Institute of Pharmaceutical Biotechnology, 89081 Ulm University, Ulm, Germany.
- Institute of Structural Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany.
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9
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Oh JY, Lim CS, Yoo KS, Park H, Park YS, Kim EG, Lee YS, Kaang BK, Kim HK. Adenomatous polyposis coli-stimulated GEF 1 (Asef1) is a negative regulator of excitatory synaptic function. J Neurochem 2018; 147:595-608. [PMID: 30125942 DOI: 10.1111/jnc.14570] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/18/2018] [Accepted: 08/16/2018] [Indexed: 01/06/2023]
Abstract
Guanine nucleotide exchange factors (GEFs) play important roles in many cellular processes, including regulation of the structural plasticity of dendritic spines. A GEF protein, adenomatous polyposis coli-stimulated GEF 1 (Asef1, ARHGEF4) is highly expressed in the nervous system. However, the function of Asef1 has not been investigated in neurons. Here, we present evidence showing that Asef1 negatively regulates the synaptic localization of postsynaptic density protein 95 (PSD-95) in the excitatory synapse by inhibiting Staufen-mediated synaptic localization of PSD-95. Accordingly, Asef1 expression impairs synaptic transmission in hippocampal cultured neurons. In addition, neuronal activity facilitates the dissociation of Asef1 from Staufen in a phosphoinositide 3 kinase (PI3K)-dependent manner. Taken together, our data reveal Asef1 functions as a negative regulator of synaptic localization of PSD-95 and synaptic transmission.
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Affiliation(s)
- Jun-Young Oh
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea.,Korea Brain Research Institute, Daegu, Korea
| | - Chae-Seok Lim
- Department of Pharmacology, Wonkwang University School of Medicine, Iksan, Korea
| | - Ki-Seo Yoo
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea
| | | | - Young Seok Park
- Department of Neurosurgery, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Eung-Gook Kim
- Department of Medicine and Biochemistry, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Yong-Seok Lee
- Department of Physiology, Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Hyong Kyu Kim
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea
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10
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Lazzaretti D, Bandholz-Cajamarca L, Emmerich C, Schaaf K, Basquin C, Irion U, Bono F. The crystal structure of Staufen1 in complex with a physiological RNA sheds light on substrate selectivity. Life Sci Alliance 2018; 1:e201800187. [PMID: 30456389 PMCID: PMC6238398 DOI: 10.26508/lsa.201800187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 01/29/2023] Open
Abstract
Combination of in vitro and in vivo data show that RNA sequence influences Staufen target recognition and that protein–RNA base contacts are required for Staufen function in Drosophila. During mRNA localization, RNA-binding proteins interact with specific structured mRNA localization motifs. Although several such motifs have been identified, we have limited structural information on how these interact with RNA-binding proteins. Staufen proteins bind structured mRNA motifs through dsRNA-binding domains (dsRBD) and are involved in mRNA localization in Drosophila and mammals. We solved the structure of two dsRBDs of human Staufen1 in complex with a physiological dsRNA sequence. We identified interactions between the dsRBDs and the RNA sugar–phosphate backbone and direct contacts of conserved Staufen residues to RNA bases. Mutating residues mediating nonspecific backbone interactions only affected Staufen function in Drosophila when in vitro binding was severely reduced. Conversely, residues involved in base-directed interactions were required in vivo even when they minimally affected in vitro binding. Our work revealed that Staufen can read sequence features in the minor groove of dsRNA and suggests that these influence target selection in vivo.
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Affiliation(s)
| | | | | | - Kristina Schaaf
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Claire Basquin
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Uwe Irion
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Fulvia Bono
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, UK
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11
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Ravanidis S, Kattan FG, Doxakis E. Unraveling the Pathways to Neuronal Homeostasis and Disease: Mechanistic Insights into the Role of RNA-Binding Proteins and Associated Factors. Int J Mol Sci 2018; 19:ijms19082280. [PMID: 30081499 PMCID: PMC6121432 DOI: 10.3390/ijms19082280] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The timing, dosage and location of gene expression are fundamental determinants of brain architectural complexity. In neurons, this is, primarily, achieved by specific sets of trans-acting RNA-binding proteins (RBPs) and their associated factors that bind to specific cis elements throughout the RNA sequence to regulate splicing, polyadenylation, stability, transport and localized translation at both axons and dendrites. Not surprisingly, misregulation of RBP expression or disruption of its function due to mutations or sequestration into nuclear or cytoplasmic inclusions have been linked to the pathogenesis of several neuropsychiatric and neurodegenerative disorders such as fragile-X syndrome, autism spectrum disorders, spinal muscular atrophy, amyotrophic lateral sclerosis and frontotemporal dementia. This review discusses the roles of Pumilio, Staufen, IGF2BP, FMRP, Sam68, CPEB, NOVA, ELAVL, SMN, TDP43, FUS, TAF15, and TIA1/TIAR in RNA metabolism by analyzing their specific molecular and cellular function, the neurological symptoms associated with their perturbation, and their axodendritic transport/localization along with their target mRNAs as part of larger macromolecular complexes termed ribonucleoprotein (RNP) granules.
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Affiliation(s)
- Stylianos Ravanidis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Fedon-Giasin Kattan
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Epaminondas Doxakis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
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12
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Park E, Maquat LE. Staufen-mediated mRNA decay. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:423-35. [PMID: 23681777 DOI: 10.1002/wrna.1168] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/28/2013] [Accepted: 03/28/2013] [Indexed: 12/26/2022]
Abstract
Staufen1 (STAU1)-mediated mRNA decay (SMD) is an mRNA degradation process in mammalian cells that is mediated by the binding of STAU1 to a STAU1-binding site (SBS) within the 3'-untranslated region (3'-UTR) of target mRNAs. During SMD, STAU1, a double-stranded (ds) RNA-binding protein, recognizes dsRNA structures formed either by intramolecular base pairing of 3'-UTR sequences or by intermolecular base pairing of 3'-UTR sequences with a long-noncoding RNA (lncRNA) via partially complementary Alu elements. Recently, STAU2, a paralog of STAU1, has also been reported to mediate SMD. Both STAU1 and STAU2 interact directly with the ATP-dependent RNA helicase UPF1, a key SMD factor, enhancing its helicase activity to promote effective SMD. Moreover, STAU1 and STAU2 form homodimeric and heterodimeric interactions via domain-swapping. Because both SMD and the mechanistically related nonsense-mediated mRNA decay (NMD) employ UPF1; SMD and NMD are competitive pathways. Competition contributes to cellular differentiation processes, such as myogenesis and adipogenesis, placing SMD at the heart of various physiologically important mechanisms.
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Affiliation(s)
- Eonyoung Park
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, Center for RNA Biology, University of Rochester, Rochester, NY, USA
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13
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Bilogan CK, Horb ME. Xenopus staufen2 is required for anterior endodermal organ formation. Genesis 2012; 50:251-9. [PMID: 22162130 DOI: 10.1002/dvg.22000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 01/30/2023]
Abstract
Defining the regulatory molecular networks involved in patterning the developing anterior endoderm is essential to understand how the pancreas, liver, stomach, and duodenum are discretely specified from each other. In this study, we analyzed the expression and function of the double-stranded RNA-binding protein Staufen2 in Xenopus laevis endoderm. We found that staufen2 was broadly expressed within the developing endoderm beginning at gastrulation becoming localized to the anterior endoderm at later stages. Through morpholino-mediated knockdown, we demonstrate that Staufen2 function is required for proper formation of the stomach, liver, and pancreas. We define that its function is required during gastrulation for proper patterning of the dorsal-ventral axis and that it acts to regulate expression of BMP signaling components.
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Affiliation(s)
- Cassandra K Bilogan
- Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, USA
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Martel C, Dugré-Brisson S, Boulay K, Breton B, Lapointe G, Armando S, Trépanier V, Duchaîne T, Bouvier M, Desgroseillers L. Multimerization of Staufen1 in live cells. RNA (NEW YORK, N.Y.) 2010; 16:585-97. [PMID: 20075165 PMCID: PMC2822923 DOI: 10.1261/rna.1664210] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Transport of mRNA is an efficient mechanism to target proteins to specific regions of a cell. Although it is well documented that mRNAs are transported in ribonucleoprotein (RNP) complexes, several of the mechanisms involved in complex formation and localization are poorly understood. Staufen (Stau) 1, a double-stranded RNA-binding protein, is a well accepted marker of mRNA transport complexes. In this manuscript, we provide evidence that Stau1 self-associates in live cells using immunoprecipitation and bioluminescence resonance energy transfer (BRET) assays. The double-stranded RNA-binding domains dsRBD3 and dsRBD4 contributed about half of the signal, suggesting that Stau1 RNA-binding activity is involved in Stau1 self-association. Protein-protein interaction also occurred, via dsRBD5 and dsRBD2, as shown by in vitro pull-down, yeast two-hybrid, and BRET assays in live cells. Interestingly, Stau1 self-association contributes to the formation of oligomeric complexes as evidenced by the coexpression of split Renilla luciferase halves covalently linked to Stau1 in a protein complementation assay (PCA) combined with a BRET assay with Stau1-YFP. Moreover, we showed that these higher-order Stau1-containing complexes carry RNAs when the RNA stain SYTO 14 was used as the energy acceptor in the PCA/BRET assay. The oligomeric composition of Stau1-containing complexes and the presence of specific mRNAs have been confirmed by biochemical approaches involving two successive immunoprecipitations of Stau1-tagged molecules followed by qRT-PCR amplification. Altogether, these results indicate that Stau1 self-associates in mRNPs via its multiple functional domains that can select mRNAs to be transported and establish protein-protein interaction.
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Affiliation(s)
- Catherine Martel
- Département de Biochimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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15
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Yamaguchi Y, Oohinata R, Naiki T, Irie K. Stau1 negatively regulates myogenic differentiation in C2C12 cells. Genes Cells 2008; 13:583-92. [PMID: 18422603 DOI: 10.1111/j.1365-2443.2008.01189.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sequential expression of myogenic regulatory factors (MRFs) such as MyoD and myogenin drives myogenic differentiation. Besides transcriptional activation of MRFs, this process is also coordinated by post-transcriptional regulation; MyoD and myogenin mRNAs are stabilized by RNA-binding protein HuR. Stau1 is known to regulate mRNA stability in a complex with Upf1, which is termed Stau1-mediated mRNA decay (SMD). We describe here that Stau1 is involved in the regulation of myogenesis. We found that knockdown of Stau1 promotes myogenesis including the expression of a muscle-specific marker protein, myoglobin, in C2C12 myoblasts. MyoD induces myogenin expression in response to induction of myogenesis, which is a key step to start myogenesis. The level of MyoD protein was not affected when Stau1 was depleted by siRNA, whereas the levels of myogenin mRNA and protein were increased in Stau1-knockdown cells. Interestingly, myogenin promoter activity was also increased in Stau1-knockdown cells in the absence of induction of myogenesis. Furthermore, Stau1-knockdown cells spontaneously progressed myogenesis including the expression of muscle-specific protein. Although Stau1 is involved in mRNA decay together with Upf1, Upf1-knockdown did not affect progression of myogenesis. Our results suggest that Stau1 negatively regulates myogenesis in C2C12 myoblasts through a mechanism that is different from SMD.
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Affiliation(s)
- Yukio Yamaguchi
- Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan
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16
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Staufen1 regulation of protein synthesis-dependent long-term potentiation and synaptic function in hippocampal pyramidal cells. Mol Cell Biol 2008; 28:2896-907. [PMID: 18316402 DOI: 10.1128/mcb.01844-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Staufen1 (Stau1) is an RNA-binding protein involved in transport, localization, decay, and translational control of mRNA. In neurons, it is present in cell bodies and also in RNA granules which are transported along dendrites. Dendritic mRNA localization might be involved in long-term synaptic plasticity and memory. To determine the role of Stau1 in synaptic function, we examined the effects of Stau1 down-regulation in hippocampal slice cultures using small interfering RNA (siRNA). Biolistic transfection of Stau1 siRNA resulted in selective down-regulation of Stau1 in slice cultures. Consistent with a role of Stau1 in transporting mRNAs required for synaptic plasticity, Stau1 down-regulation impaired the late form of chemically induced long-term potentiation (L-LTP) without affecting early-LTP, mGluR1/5-mediated long-term depression, or basal evoked synaptic transmission. Stau1 down-regulation decreased the amplitude and frequency of miniature excitatory postsynaptic currents, suggesting a role in maintaining efficacy at hippocampal synapses. At the cellular level, Stau1 down-regulation shifted spine shape from regular to elongated spines, without changes in spine density. The change in spine shape could be rescued by an RNA interference-resistant Stau1 isoform. Therefore, Stau1 is important for processing and/or transporting in dendrites mRNAs that are critical in regulation of synaptic strength and maintenance of functional connectivity changes underlying hippocampus-dependent learning and memory.
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17
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Furic L, Maher-Laporte M, DesGroseillers L. A genome-wide approach identifies distinct but overlapping subsets of cellular mRNAs associated with Staufen1- and Staufen2-containing ribonucleoprotein complexes. RNA (NEW YORK, N.Y.) 2008; 14:324-35. [PMID: 18094122 PMCID: PMC2212254 DOI: 10.1261/rna.720308] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Messenger RNAs are associated with multiple RNA-binding proteins to form ribonucleoprotein (mRNP) complexes. These proteins are important regulators of the fate of their target mRNAs. In human cells, Staufen1 and Staufen2 proteins, coded by two different genes, are double-stranded RNA-binding proteins involved in several cellular functions including mRNA localization, translation, and decay. Although 51% identical, these proteins are nevertheless found in different RNA particles. In addition, differential splicing events generate Staufen2 isoforms that only differ at their N-terminal extremities. In this paper, we used a genome-wide approach to identify and compare the mRNA targets of mammalian Staufen proteins. The mRNA content of Staufen mRNPs was identified by probing DNA microarrays with probes derived from mRNAs isolated from immunopurified Staufen-containing complexes following transfection of HEK293T cells with Stau1(55)-HA, Stau2(59)-HA, or Stau2(62)-HA expressors. Our results indicate that 7% and 11% of the cellular RNAs expressed in HEK293T cells are found in Stau1- and in Stau2-containing mRNPs, respectively. A comparison of Stau1- and Stau2-containing mRNAs identifies a relatively low percentage of common mRNAs; the percentage of common mRNAs highly increases when mRNAs in Stau2(59)-HA- and Stau2(62)-containing mRNPs are compared. There is a predominance of mRNAs involved in cell metabolism, transport, transcription, regulation of cell processes, and catalytic activity. All these subsets of mRNAs are mostly distinct from those associated with FMRP or IMP, although some mRNAs overlap. Consistent with a model of post-transcriptional gene regulation, our results show that Stau1- and Stau2-mRNPs associate with distinct but overlapping sets of cellular mRNAs.
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Affiliation(s)
- Luc Furic
- Département de Biochimie, Université de Montréal, Montréal, Québec, Canada H3C 3J7
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18
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Jeong JH, Nam YJ, Kim SY, Kim EG, Jeong J, Kim HK. The transport of Staufen2-containing ribonucleoprotein complexes involves kinesin motor protein and is modulated by mitogen-activated protein kinase pathway. J Neurochem 2007; 102:2073-2084. [PMID: 17587311 DOI: 10.1111/j.1471-4159.2007.04697.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is increasing evidence showing that mRNA is transported to the neuronal dendrites in ribonucleoprotein (RNP) complexes or RNA granules, which are aggregates of mRNA, rRNA, ribosomal proteins, and RNA-binding proteins. In these RNP complexes, Staufen, a double-stranded RNA-binding protein, is believed to be a core component that plays a key role in the dendritic mRNA transport. This study investigated the molecular mechanisms of the dendritic mRNA transport using green fluorescent protein-tagged Staufen2 produced employing a Sindbis viral expression system. The kinesin heavy chain was found to be associated with Staufen2. The inhibition of kinesin resulted in a significant decrease in the level of dendritic transport of the Staufen2-containing RNP complexes in neurons under non-stimulating or stimulating conditions. This suggests that the dendritic transport of the Staufen2-containing RNP complexes use kinesin as a motor protein. A mitogen-activated protein kinase inhibitor, PD98059, inhibited the activity-induced increase in the amount of both the Staufen2-containing RNP complexes and Ca(2+)/calmodulin-dependent protein kinase II alpha-subunit mRNA in the distal dendrites of cultured hippocampal neurons. Overall, these results suggest that dendritic mRNA transport is mediated via the Staufen2 and kinesin motor proteins and might be modulated by the neuronal activity and mitogen-activated protein kinase pathway.
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Affiliation(s)
- Ji-Hye Jeong
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Yeon-Ju Nam
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Seok-Yong Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Eung-Gook Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Jooyoung Jeong
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Hyong Kyu Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
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19
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Miki T, Takano K, Yoneda Y. The role of mammalian Staufen on mRNA traffic: a view from its nucleocytoplasmic shuttling function. Cell Struct Funct 2006; 30:51-6. [PMID: 16377940 DOI: 10.1247/csf.30.51] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The localization of mRNA in neuronal dendrites plays a role in both locally and temporally regulated protein synthesis, which is required for certain forms of synaptic plasticity. RNA granules constitute a dendritic mRNA transport machinery in neurons, which move along microtubules. RNA granules contain densely packed clusters of ribosomes, but lack some factors that are required for translation, suggesting that they are translationally incompetent. Recently some of the components of RNA granules have been identified, and their functions are in the process of being examined, in attempts to better understand the properties of RNA granules. Mammalian Staufen, a double-stranded RNA binding protein, is a component of RNA granules. Staufen is localized in the somatodendritic domain of neurons, and plays an important role in dendritic mRNA targeting. Recently, one of the mammalian homologs of Staufen, Staufen2 (Stau2), was shown to shuttle between the nucleus and the cytoplasm. This finding suggests the possibility that Stau2 binds RNA in the nucleus and that this ribonucleoprotein particle is transported from the nucleus to RNA granules in the cytoplasm. A closer study of this process might provide a clue to the mechanism by which RNA granules are formed.
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Affiliation(s)
- Takashi Miki
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
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20
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Gautrey H, McConnell J, Hall J, Hesketh J. Polarised distribution of the RNA-binding protein Staufen in differentiated intestinal epithelial cells. FEBS Lett 2005; 579:2226-30. [PMID: 15811346 DOI: 10.1016/j.febslet.2005.02.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 01/21/2005] [Accepted: 02/08/2005] [Indexed: 11/22/2022]
Abstract
mRNA localisation, as a mechanism for directing localised protein synthesis, plays a vital role in the functioning of certain cells, such as neurons and oocytes. Potentially this mechanism may also occur in polarised intestinal epithelial cells. Here we show that Staufen1(55), a protein involved in mRNA localisation and transport, is asymmetrically distributed in differentiated Caco-2 intestinal epithelial cells and partly co-localised with calnexin, a marker of the endoplasmic reticulum. The localisation to the apical region of the cell indicates that Staufen may be involved in localisation of transcripts to this domain.
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Affiliation(s)
- Hannah Gautrey
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle-upon-Tyne NE1 7RU, UK
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21
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Brendel C, Rehbein M, Kreienkamp HJ, Buck F, Richter D, Kindler S. Characterization of Staufen 1 ribonucleoprotein complexes. Biochem J 2004; 384:239-46. [PMID: 15303970 PMCID: PMC1134106 DOI: 10.1042/bj20040812] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Revised: 07/21/2004] [Accepted: 08/10/2004] [Indexed: 10/26/2022]
Abstract
In Drosophila oocytes and neuroblasts, the double-stranded RNA binding protein Staufen assembles into ribonucleoprotein particles, which mediate cytoplasmic mRNA trafficking and translation. Two different mammalian orthologues also appear to reside in distinct RNA-containing particles. To date, relatively little is known about the molecular composition of Staufen-containing ribonucleoprotein complexes. Here, we have used a novel one-step affinity purification protocol to identify components of Staufen 1-containing particles. Whereas the nucleocytoplasmic RNA-binding protein nucleolin is linked to Staufen in an RNA-dependent manner, the association of protein phosphatase 1, the microtubule-dependent motor protein kinesin and several components of the large and small ribosomal subunits with Staufen ribonucleoprotein complexes is RNA-independent. Notably, all these components do not co-purify with a second RNA-binding protein, hnRNPK (heterogeneous ribonucleoprotein K), demonstrating the high specificity of the purification protocol. Furthermore, pull-down and immunoprecipitation experiments suggest a direct interaction between Staufen 1 and the ribosomal protein P0 in vitro as well as in cells. In cell fractionation and sucrose gradient assays, Staufen co-fractionates with intact ribosomes and polysomes, but not with the isolated 40 S ribosomal subunit. Taken together, these findings imply that, in the cytoplasm of mammalian cells, an association with the ribosomal P-stalk protein P0 recruits Staufen 1 into ribosome-containing ribonucleoprotein particles, which also contain kinesin, protein phosphatase 1 and nucleolin.
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Key Words
- ribonucleoprotein particle
- ribosome
- rna sorting
- rna-binding protein
- translation
- dsrbd, double-stranded rna-binding domain
- ef1α, elongation factor 1α
- (e)gfp, (enhanced) green fluorescent protein
- fmrp, fragile x mental retardation protein 1
- gkap/sapap1, guanylate kinase-associated protein/sap90/psd-95-associated protein
- gst, glutathione s-transferase
- hek, human embryonic kidney
- hnrnp(k/u), heterogeneous ribonucleoprotein k or u respectively
- ip buffer, immunoprecipitation buffer
- pp1, protein phosphatase-1
- (m)rnp, (messenger) ribonucleoprotein particle
- nfar, nuclear factor associated with double-stranded rna
- pabp, poly(a)+-binding protein
- rha, rna helicase a
- rstau, rat staufen
- sstrip, somatostatin receptor-interacting protein
- stau1, staufen 1
- stau2, staufen 2
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Affiliation(s)
- Cornelia Brendel
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Monika Rehbein
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Hans-Jürgen Kreienkamp
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Friedrich Buck
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Dietmar Richter
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Stefan Kindler
- Institute for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany
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Miki T, Yoneda Y. Alternative splicing of Staufen2 creates the nuclear export signal for CRM1 (Exportin 1). J Biol Chem 2004; 279:47473-9. [PMID: 15364930 DOI: 10.1074/jbc.m407883200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian Staufen2 (Stau2), a brain-specific double-stranded RNA-binding protein, is involved in the localization of mRNA in neurons. To gain insights into the function of Stau2, the subcellular localization of Stau2 isoforms fused to the green fluorescence protein was examined. Fluorescence microscopic analysis showed that Stau2 functions as a nucleocytoplasmic shuttle protein. The nuclear export of the 62-kDa isoform of Stau2 (Stau2(62)) is mediated by the double-stranded RNA-binding domain 3 (RBD3) because a mutation to RBD3 led to nuclear accumulation. On the other hand, the shorter isoform of Stau2, Stau2(59), is exported from the nucleus by two distinct pathways, one of which is RBD3-mediated and the other of which is CRM1 (exportin 1)-dependent. The nuclear export signal recognized by CRM1 was found to be located in the N-terminal region of Stau2(59). These results suggest that Stau2 may carry a variety of RNAs out of the nucleus, using the two export pathways. The present study addresses the issue of why plural Stau2 isoforms are expressed in neurons.
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Affiliation(s)
- Takashi Miki
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
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Bélanger G, Stocksley MA, Vandromme M, Schaeffer L, Furic L, DesGroseillers L, Jasmin BJ. Localization of the RNA-binding proteins Staufen1 and Staufen2 at the mammalian neuromuscular junction. J Neurochem 2003; 86:669-77. [PMID: 12859680 DOI: 10.1046/j.1471-4159.2003.01883.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Staufen is an RNA-binding protein, first identified for its role in oogenesis and CNS development in Drosophila. Two mammalian homologs of Staufen have been identified and shown to bind double-stranded RNA and tubulin, and to function in the somatodendritic transport of mRNA in neurons. Here, we examined whether Staufen proteins are expressed in skeletal muscle in relation to the neuromuscular junction. Immunofluorescence experiments revealed that Staufen1 (Stau1) and Staufen2 (Stau2) accumulate preferentially within the postsynaptic sarcoplasm of muscle fibers as well as at newly formed ectopic synapses. Western blot analyses showed that the levels of Stau1 and Stau2 are greater in slow muscles than in fast-twitch muscles. Muscle denervation induced a significant increase in the expression of Stau1 and Stau2 in the extrasynaptic compartment of both fast and slow muscles. Consistent with these observations, we also demonstrated that expression of Stau1 and Stau2 is increased during myogenic differentiation and that treatment of myotubes with agrin and neuregulin induces a further increase in the expression of both Staufen proteins. We propose that Stau1 and Stau2 are key components of the postsynaptic apparatus in muscle, and that they contribute to the maturation and plasticity of the neuromuscular junction.
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MESH Headings
- Agrin/pharmacology
- Animals
- Blotting, Western
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Line
- Mice
- Mice, Inbred C57BL
- Muscle Denervation
- Muscle Fibers, Fast-Twitch/chemistry
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Slow-Twitch/chemistry
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/cytology
- Muscle, Skeletal/metabolism
- Myoblasts/cytology
- Myoblasts/metabolism
- Nerve Tissue Proteins/analysis
- Nerve Tissue Proteins/biosynthesis
- Neuregulins/pharmacology
- Neuromuscular Junction/metabolism
- RNA-Binding Proteins/analysis
- RNA-Binding Proteins/biosynthesis
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Affiliation(s)
- Guy Bélanger
- Department of Cellular and Molecular Medicine, and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Affiliation(s)
- Fabrice Roegiers
- Department of Physiology, Howard Hughes Medical Institute, University of California, 533 Parnassus Avenue, San Francisco, CA 94122, USA.
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Monshausen M, Rehbein M, Richter D, Kindler S. The RNA-binding protein Staufen from rat brain interacts with protein phosphatase-1. J Neurochem 2002; 81:557-64. [PMID: 12065664 DOI: 10.1046/j.1471-4159.2002.00887.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In mammalian neurones, homologues of the Drosophila RNA-binding protein Staufen are part of ribonucleoprotein complexes that move bidirectionally along dendritic microtubules and appear to regulate mRNA translocation and translation. In this study, putative components of Staufen granules were identified in a yeast two-hybrid screen of a rat brain cDNA library with a rat Staufen bait. Protein phosphatase-1 was found as an interacting partner. Binding appears to be mediated by a five amino acid residue sequence motif (R-K-V-T-F) in Staufen that is conserved in a number of proteins interacting with the phosphatase. A two amino acid residue mutation within this motif (R-K-V-G-A) disrupted the interaction. A cytoplasmic interaction of both proteins was shown by coimmunoprecipitation of rat Staufen and protein phosphatase-1 from the cytoplasm of transfected cells and rat brain homogenates. In mammalian brain, the phosphatase represents the first described endogenous interaction partner of Staufen. In primary hippocampal neurones, both proteins partially colocalize in somata and neuronal processes. Staufen does not modulate the in vitro protein phosphatase activity. These findings show that protein phosphatase-1 is a native component of Staufen particles. Cellular functions of Staufen may be regulated via phosphorylation or Staufen may recruite the phosphatase into specific ribonucleoprotein complexes.
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Affiliation(s)
- Michaela Monshausen
- Institute for Cell Biochemistry and Clinical Neurobiology, University of Hamburg, Germany
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26
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Sargent CA, Boucher CA, Blanco P, Chalmers IJ, Highet L, Hall N, Ross N, Crow T, Affara NA. Characterization of the human Xq21.3/Yp11 homology block and conservation of organization in primates. Genomics 2001; 73:77-85. [PMID: 11352568 DOI: 10.1006/geno.2000.6491] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Xq21.3/Yp11 homology block on the human sex chromosomes represents a recent addition to the Y chromosome through a transposition event. It is believed that this transfer of material occurred after the divergence of the hominid lineage from other great apes. In this paper we investigate the structure and evolution of the block through fluorescence in situ hybridisation, contig assembly, the polymerase chain reaction, exon trapping, sequence comparison, and annotation of sequence data. The overall structure is well conserved between the human X chromosome and the Y chromosome as well as between the X chromosomes from different primates. Although the sequence data reveal a high level of nucleotide sequence identity for the human X and Y, there are regions of significant divergence, such as that around the marker DXS214. These are presumably the consequence of multiple rearrangements during evolution and are of particular importance with respect to the potential gene content in this segment of the interval.
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Affiliation(s)
- C A Sargent
- Human Molecular Genetics Group, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, United Kingdom
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Monshausen M, Putz U, Rehbein M, Schweizer M, DesGroseillers L, Kuhl D, Richter D, Kindler S. Two rat brain staufen isoforms differentially bind RNA. J Neurochem 2001; 76:155-65. [PMID: 11145988 DOI: 10.1046/j.1471-4159.2001.00061.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In neurones, a limited number of mRNAs is found in dendrites, including transcripts encoding the microtubule-associated protein 2 (MAP2). Recently, we identified a cis-acting dendritic targeting element (DTE) in MAP2 mRNAs. Here we used the yeast tri-hybrid system to identify potential trans-acting RNA-binding factors of the DTE. A cDNA clone was isolated that encodes a member of a mammalian protein family that is highly homologous to the Drosophila RNA-binding protein Staufen. Mammalian Staufen appears to be expressed in most tissues and brain areas. Two distinct rat brain Staufen isoforms, rStau+I6 and rStau-I6, are encoded by alternatively spliced mRNAs. Both isoforms contain four double-stranded RNA-binding domains (dsRBD). In the larger rStau+I6 isoform, six additional amino acids are inserted in the second dsRBD. Although both isoforms interacted with the MAP2-DTE and various additional RNA fragments in an in vitro north-western assay, rStau-I6 exhibited a stronger signal of bound radioactively labelled RNAs as compared with rStau+I6. Using an antibody directed against mammalian Staufen, the protein was detected in somata and dendrites of neurones of the adult rat hippocampus and cerebral cortex. Ultrastructural studies revealed that in dendrites, rat Staufen accumulates along microtubules. Thus in neurones, rat Staufen may serve to link RNAs to the dendritic microtubular cytoskeleton and may thereby regulate their subcellular localization.
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Affiliation(s)
- M Monshausen
- Institute for Cell Biochemistry and Clinical Neurobiology, University of Hamburg, Germany
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