1
|
Nagel M, Noss M, Xu J, Horn N, Ueffing M, Boldt K, Schuele R. The kinesin motor KIF1C is a putative transporter of the exon junction complex in neuronal cells. RNA (NEW YORK, N.Y.) 2022; 29:rna.079426.122. [PMID: 36316088 PMCID: PMC9808568 DOI: 10.1261/rna.079426.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Neurons critically depend on regulated RNA localization and tight control of spatio-temporal gene expression to maintain their morphological and functional integrity. Mutations in the kinesin motor protein gene KIF1C cause Hereditary Spastic Paraplegia, an autosomal recessive disease leading to predominant degeneration of the long axons of central motoneurons. In this study we aimed to gain insight into the molecular function of KIF1C and understand how KIF1C dysfunction contributes to motoneuron degeneration. We used affinity proteomics in neuronally differentiated neuroblastoma cells (SH-SY5Y) to identify the protein complex associated with KIF1C in neuronal cells; candidate interactions were then validated by immunoprecipitation and mislocalization of putative KIF1C cargoes was studied by immunostainings. We found KIF1C to interact with all core components of the exon junction complex (EJC); expression of mutant KIF1C in neuronal cells leads to loss of the typical localization distally in neurites. Instead, EJC core components accumulate in the pericentrosomal region, here co-localizing with mutant KIF1C. These findings suggest KIF1C as a neuronal transporter of the EJC. Interestingly, the binding of KIF1C to the EJC is RNA-mediated, as treatment with RNAse prior to immunoprecipitation almost completely abolishes the interaction. Silica-based solid-phase extraction of UV-crosslinked RNA-protein complexes furthermore supports direct interaction of KIF1C with RNA, as recently also demonstrated for kinesin heavy chain. Taken together, our findings are consistent with a model where KIF1C transports mRNA in an EJC-bound and therefore transcriptionally silenced state along neurites, thus providing the missing link between the EJC and mRNA localization in neurons.
Collapse
Affiliation(s)
- Maike Nagel
- German Center for Neurodegenerative Diseases, Tuebingen; Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; Graduate School of Cellular and Molecular Neuroscience
| | - Marvin Noss
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen
| | - Jishu Xu
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; Institute of Medical Genetics and Applied Genomics, University of Tuebingen; Graduate School
| | - Nicola Horn
- Institute for Ophthalmic Research, University of Tuebingen
| | - Marius Ueffing
- Institute of Ophthalmic Research, University of Tuebingen
| | - Karsten Boldt
- Institute of Ophthalmic Research, University of Tuebingen
| | - Rebecca Schuele
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; German Center for Neurodegenerative Diseases, Tuebingen
| |
Collapse
|
2
|
Pichon X, Moissoglu K, Coleno E, Wang T, Imbert A, Robert MC, Peter M, Chouaib R, Walter T, Mueller F, Zibara K, Bertrand E, Mili S. The kinesin KIF1C transports APC-dependent mRNAs to cell protrusions. RNA (NEW YORK, N.Y.) 2021; 27:1528-1544. [PMID: 34493599 PMCID: PMC8594469 DOI: 10.1261/rna.078576.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 09/01/2021] [Indexed: 05/25/2023]
Abstract
RNA localization and local translation are important for numerous cellular functions. In mammals, a class of mRNAs localize to cytoplasmic protrusions in an APC-dependent manner, with roles during cell migration. Here, we investigated this localization mechanism. We found that the KIF1C motor interacts with APC-dependent mRNAs and is required for their localization. Live cell imaging revealed rapid, active transport of single mRNAs over long distances that requires both microtubules and KIF1C. Two-color imaging directly revealed single mRNAs transported by single KIF1C motors, with the 3'UTR being sufficient to trigger KIF1C-dependent RNA transport and localization. Moreover, KIF1C remained associated with peripheral, multimeric RNA clusters and was required for their formation. These results reveal a widespread RNA transport pathway in mammalian cells, in which the KIF1C motor has a dual role in transporting RNAs and clustering them within cytoplasmic protrusions. Interestingly, KIF1C also transports its own mRNA, suggesting a possible feedback loop acting at the level of mRNA transport.
Collapse
Affiliation(s)
- Xavier Pichon
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
| | - Emeline Coleno
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Tianhong Wang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
| | - Arthur Imbert
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 77300 Fontainebleau, France
- Institut Curie, 75248 Paris Cedex, France
- INSERM, U900, 75248 Paris Cedex, France
| | - Marie-Cécile Robert
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Marion Peter
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
| | - Racha Chouaib
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Thomas Walter
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 77300 Fontainebleau, France
- Institut Curie, 75248 Paris Cedex, France
- INSERM, U900, 75248 Paris Cedex, France
| | - Florian Mueller
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 75015 Paris, France
- C3BI, USR 3756 IP CNRS - Paris, France
| | - Kazem Zibara
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
- ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
| |
Collapse
|
3
|
Fan R, Lai KO. Understanding how kinesin motor proteins regulate postsynaptic function in neuron. FEBS J 2021; 289:2128-2144. [PMID: 34796656 DOI: 10.1111/febs.16285] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 11/08/2021] [Accepted: 11/17/2021] [Indexed: 01/07/2023]
Abstract
The Kinesin superfamily proteins (KIFs) are major molecular motors that transport diverse set of cargoes along microtubules to both the axon and dendrite of a neuron. Much of our knowledge about kinesin function is obtained from studies on axonal transport. Emerging evidence reveals how specific kinesin motor proteins carry cargoes to dendrites, including proteins, mRNAs and organelles that are crucial for synapse development and plasticity. In this review, we will summarize the major kinesin motors and their associated cargoes that have been characterized to regulate postsynaptic function in neuron. We will also discuss how specific kinesins are selectively involved in the development of excitatory and inhibitory postsynaptic compartments, their regulation by post-translational modifications (PTM), as well as their roles beyond conventional transport carrier.
Collapse
Affiliation(s)
- Ruolin Fan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Kwok-On Lai
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| |
Collapse
|
4
|
Choi K, Lee J, Kang HJ. Myelination defects in the medial prefrontal cortex of Fkbp5 knockout mice. FASEB J 2021; 35:e21297. [PMID: 33410216 DOI: 10.1096/fj.202001883r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/14/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022]
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis plays a principal role in stress response regulation and has been implicated in the etiology of stress-related disorders. The HPA axis regulates the normal synthesis and release of glucocorticoids; dysregulation of the HPA axis causes abnormal responses to stress. FK506-binding protein 5 (FKBP5), a co-chaperone of heat shock protein 90 in the glucocorticoid receptor (GR) molecular complex, is a key GR sensitivity regulator. FKBP5 single nucleotide polymorphisms are associated with dysregulated HPA axis and increased risk of stress-related disorders, including posttraumatic stress disorder (PTSD) and depression. In this study, we profiled the microRNAs (miRNAs) in the medial prefrontal cortex of Fkbp5 knockout (Fkbp5-/- ) mice and identified the target genes of differentially expressed miRNAs using sequence-based miRNA target prediction. Gene ontology analysis revealed that the differentially expressed miRNAs were involved in nervous system development, regulation of cell migration, and intracellular signal transduction. The validation of the expression of predicted target genes using quantitative polymerase chain reaction revealed that the expression of axon development-related genes, specifically actin-binding LIM protein 1 (Ablim1), lemur tyrosine kinase 2 (Lmtk2), kinesin family member 5c (Kif5c), neurofascin (Nfasc), and ephrin type-A receptor 4 (Epha4), was significantly decreased, while that of brain-derived neurotrophic factor (Bdnf) was significantly increased in the brain of Fkbp5-/- mice. These results suggest that axonal development-related genes can serve as potential targets in future studies focused on understanding the pathophysiology of PTSD.
Collapse
Affiliation(s)
- Koeul Choi
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - Joonhee Lee
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - Hyo Jung Kang
- Department of Life Science, Chung-Ang University, Seoul, Korea
| |
Collapse
|
5
|
Park J, Farris S. Spatiotemporal Regulation of Transcript Isoform Expression in the Hippocampus. Front Mol Neurosci 2021; 14:694234. [PMID: 34305526 PMCID: PMC8295539 DOI: 10.3389/fnmol.2021.694234] [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: 04/12/2021] [Accepted: 06/15/2021] [Indexed: 11/13/2022] Open
Abstract
Proper development and plasticity of hippocampal neurons require specific RNA isoforms to be expressed in the right place at the right time. Precise spatiotemporal transcript regulation requires the incorporation of essential regulatory RNA sequences into expressed isoforms. In this review, we describe several RNA processing strategies utilized by hippocampal neurons to regulate the spatiotemporal expression of genes critical to development and plasticity. The works described here demonstrate how the hippocampus is an ideal investigative model for uncovering alternate isoform-specific mechanisms that restrict the expression of transcripts in space and time.
Collapse
Affiliation(s)
- Joun Park
- Fralin Biomedical Research Institute, Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, United States
| | - Shannon Farris
- Fralin Biomedical Research Institute, Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, United States.,Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.,Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
| |
Collapse
|
6
|
Chu JF, Majumder P, Chatterjee B, Huang SL, Shen CKJ. TDP-43 Regulates Coupled Dendritic mRNA Transport-Translation Processes in Co-operation with FMRP and Staufen1. Cell Rep 2020; 29:3118-3133.e6. [PMID: 31801077 DOI: 10.1016/j.celrep.2019.10.061] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 07/12/2019] [Accepted: 10/14/2019] [Indexed: 01/24/2023] Open
Abstract
Tightly regulated transport of messenger ribonucleoprotein (mRNP) granules to diverse locations of dendrites and axons is essential for appropriately timed protein synthesis within distinct sub-neuronal compartments. Perturbations of this regulation lead to various neurological disorders. Using imaging and molecular approaches, we demonstrate how TDP-43 co-operates with two other RNA-binding proteins, FMRP and Staufen1, to regulate the anterograde and retrograde transport, respectively, of Rac1 mRNPs in mouse neuronal dendrites. We also analyze the mechanisms by which TDP-43 mediates coupled mRNA transport-translation processes in dendritic sub-compartments by following in real-time the co-movement of RNA and endogenous fluorescence-tagged protein in neurons and by simultaneous examination of transport/translation dynamics by using an RNA biosensor. This study establishes the pivotal roles of TDP-43 in transporting mRNP granules in dendrites, inhibiting translation inside those granules, and reactivating it once the granules reach the dendritic spines.
Collapse
Affiliation(s)
- Jen-Fei Chu
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Pritha Majumder
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
| | | | - Shih-Ling Huang
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | | |
Collapse
|
7
|
Zhang L, Chen J, Cheng T, Yang H, Li H, Pan C. Identification of the key genes and characterizations of Tumor Immune Microenvironment in Lung Adenocarcinoma (LUAD) and Lung Squamous Cell Carcinoma (LUSC). J Cancer 2020; 11:4965-4979. [PMID: 32742444 PMCID: PMC7378909 DOI: 10.7150/jca.42531] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/29/2020] [Indexed: 12/13/2022] Open
Abstract
This study aimed to investigate the key genes and immune microenvironment involved in different TNM stages of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). The gene expression and clinical characteristics data were downloaded from the genomic data commons (GDC) database. After initial data processing, the characteristics of the immune microenvironment were analyzed. The differentially expressed genes (DEGs) in tumor vs. normal, and in early vs. advanced stages were screened, followed by Spearman correlation test for tumor infiltrating immune cells (TIICs) to identify immune-related genes. Finally, functional enrichment, protein-protein interaction, and survival analyses were performed. In LUAD, early stage was with higher immune scores, greater number of memory B cells and M0 macrophages compared to advanced stage. M0 and M2 macrophages, and resting memory CD4+ T cells accounted for a large proportion of TIICs in LUAD. The abundance of M0 macrophage infiltration was significantly correlated with the TNM stage and survival. In LUSC, early stage was with higher cytolytic activity and neoantigen burden compared to advanced stage. M0 and M2 macrophages, and plasma cells accounted for a large proportion of TIICs in LUSC. The abundance of resting and activated mast cells was significantly correlated with TNM stage, while resting dendritic cells, eosinophils, activated memory CD4 T cells, and mast cells were significantly correlated with prognosis. Tumor mutation burden analysis revealed that the median of variants per sample decreased from stage I to IV in LUAD, while it increased in LUSC. Further, 83 and 9 immune-related DEGs were identified in LUAD and LUSC, respectively, of which 23 genes in LUAD and 2 genes in LUSC correlated with survival. In conclusion, we identified the key genes, and characterized the tumor immune microenvironment in LUAD and LUSC which may provide therapeutic targets for the treatment of NSCLC.
Collapse
Affiliation(s)
| | - Jianhua Chen
- Thoracic Medicine Department 1, Hunan Cancer Hospital, Changsha, Hunan Province, P.R. China, 410013
| | | | | | | | | |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Mossa A, Giona F, Pagano J, Sala C, Verpelli C. SHANK genes in autism: Defining therapeutic targets. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:416-423. [PMID: 29175319 DOI: 10.1016/j.pnpbp.2017.11.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/14/2017] [Accepted: 11/18/2017] [Indexed: 01/16/2023]
Affiliation(s)
- Adele Mossa
- CNR Neuroscience Institute, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Federica Giona
- CNR Neuroscience Institute, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Jessica Pagano
- CNR Neuroscience Institute, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Carlo Sala
- CNR Neuroscience Institute, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Chiara Verpelli
- CNR Neuroscience Institute, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy.
| |
Collapse
|
10
|
Chudinova EM, Nadezhdina ES. Interactions between the Translation Machinery and Microtubules. BIOCHEMISTRY (MOSCOW) 2018; 83:S176-S189. [PMID: 29544439 DOI: 10.1134/s0006297918140146] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microtubules are components of eukaryotic cytoskeleton that are involved in the transport of various components from the nucleus to the cell periphery and back. They also act as a platform for assembly of complex molecular ensembles. Ribonucleoprotein (RNP) complexes, such as ribosomes and mRNPs, are transported over significant distances (e.g. to neuronal processes) along microtubules. The association of RNPs with microtubules and their transport along these structures are essential for compartmentalization of protein biosynthesis in cells. Microtubules greatly facilitate assembly of stress RNP granules formed by accumulation of translation machinery components during cell stress response. Microtubules are necessary for the cytoplasm-to-nucleus transport of proteins, including ribosomal proteins. At the same time, ribosomal proteins and RNA-binding proteins can influence cell mobility and cytoplasm organization by regulating microtubule dynamics. The molecular mechanisms underlying the association between the translation machinery components and microtubules have not been studied systematically; the results of such studies are mostly fragmentary. In this review, we attempt to fill this gap by summarizing and discussing the data on protein and RNA components of the translation machinery that directly interact with microtubules or microtubule motor proteins.
Collapse
Affiliation(s)
- E M Chudinova
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | | |
Collapse
|
11
|
Gnazzo MM, Uhlemann EME, Villarreal AR, Shirayama M, Dominguez EG, Skop AR. The RNA-binding protein ATX-2 regulates cytokinesis through PAR-5 and ZEN-4. Mol Biol Cell 2016; 27:3052-3064. [PMID: 27559134 PMCID: PMC5063614 DOI: 10.1091/mbc.e16-04-0219] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/17/2016] [Indexed: 12/15/2022] Open
Abstract
The mechanisms that mediate the temporal and spatial recruitment of cell division factors to the spindle midzone and midbody remain unclear. Cell division is regulated by the conserved RNA-binding protein, ATX-2/Ataxin-2, which facilitates the targeting of ZEN-4 to the spindle midzone by mediating PAR-5. The spindle midzone harbors both microtubules and proteins necessary for furrow formation and the completion of cytokinesis. However, the mechanisms that mediate the temporal and spatial recruitment of cell division factors to the spindle midzone and midbody remain unclear. Here we describe a mechanism governed by the conserved RNA-binding protein ATX-2/Ataxin-2, which targets and maintains ZEN-4 at the spindle midzone. ATX-2 does this by regulating the amount of PAR-5 at mitotic structures, particularly the spindle, centrosomes, and midbody. Preventing ATX-2 function leads to elevated levels of PAR-5, enhanced chromatin and centrosome localization of PAR-5–GFP, and ultimately a reduction of ZEN-4–GFP at the spindle midzone. Codepletion of ATX-2 and PAR-5 rescued the localization of ZEN-4 at the spindle midzone, indicating that ATX-2 mediates the localization of ZEN-4 upstream of PAR-5. We provide the first direct evidence that ATX-2 is necessary for cytokinesis and suggest a model in which ATX-2 facilitates the targeting of ZEN-4 to the spindle midzone by mediating the posttranscriptional regulation of PAR-5.
Collapse
Affiliation(s)
- Megan M Gnazzo
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Eva-Maria E Uhlemann
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Alex R Villarreal
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Masaki Shirayama
- Program in Molecular Medicine, RNA Therapeutics Institute, and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605
| | - Eddie G Dominguez
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705
| | - Ahna R Skop
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| |
Collapse
|
12
|
Sala C, Vicidomini C, Bigi I, Mossa A, Verpelli C. Shank synaptic scaffold proteins: keys to understanding the pathogenesis of autism and other synaptic disorders. J Neurochem 2015; 135:849-58. [PMID: 26338675 DOI: 10.1111/jnc.13232] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 02/01/2023]
Abstract
Shank/ProSAP proteins are essential to synaptic formation, development, and function. Mutations in the family of SHANK genes are strongly associated with autism spectrum disorders (ASD) and other neurodevelopmental and neuropsychiatric disorders, such as intellectual disability (ID), and schizophrenia. Thus, the term 'Shankopathies' identifies a number of neuronal diseases caused by alteration of Shank protein expression leading to abnormal synaptic development. With this review we want to summarize the major genetic, molecular, behavior and electrophysiological studies that provide new clues into the function of Shanks and pave the way for the discovery of new therapeutic drugs targeted to treat patients with SHANK mutations and also patients affected by other neurodevelopmental and neuropsychiatric disorders. Shank/ProSAP proteins are essential to synaptic formation, development, and function. Mutations in the family of SHANK genes are strongly associated with autism spectrum disorders (ASD) and other neurodevelopmental and neuropsychiatric disorders, such as intellectual disability (ID), and schizophrenia (SCZ). With this review we want to summarize the major genetic, molecular, behavior and electrophysiological studies that provide new clues into the function of Shanks and pave the way for the discovery of new therapeutic drugs targeted to treat patients with SHANK mutations.
Collapse
Affiliation(s)
- Carlo Sala
- CNR Neuroscience Institute and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Cinzia Vicidomini
- CNR Neuroscience Institute and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Ilaria Bigi
- CNR Neuroscience Institute and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Adele Mossa
- CNR Neuroscience Institute and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Chiara Verpelli
- CNR Neuroscience Institute and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| |
Collapse
|
13
|
Taniuchi K, Furihata M, Saibara T. KIF20A-mediated RNA granule transport system promotes the invasiveness of pancreatic cancer cells. Neoplasia 2015; 16:1082-93. [PMID: 25499221 PMCID: PMC4309255 DOI: 10.1016/j.neo.2014.10.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 10/04/2014] [Accepted: 10/13/2014] [Indexed: 01/27/2023] Open
Abstract
Pancreatic cancers are aggressive because they are highly invasive and highly metastatic; moreover, effective treatments for aggressive pancreatic cancers are lacking. Here, we report that the motor kinesin protein KIF20A promoted the motility and invasiveness of pancreatic cancer cells through transporting the RNA-binding protein IGF2BP3 and IGF2BP3-bound transcripts toward cell protrusions along microtubules. We previously reported that IGF2BP3 and its target transcripts are assembled into cytoplasmic stress granules of pancreatic cancer cells, and that IGF2BP3 promotes the motility and invasiveness of pancreatic cancer cells through regulation of localized translation of IGF2BP3-bound transcripts in cell protrusions. We show that knockdown of KIF20A inhibited accumulation of IGF2BP3-containing stress granules in cell protrusions and suppressed local protein expression from specific IGF2BP3-bound transcripts, ARF6 and ARHGEF4, in the protrusions. Our results provide insight into the link between regulation of KIF20A-mediated trafficking of IGF2BP3-containing stress granules and modulation of the motility and invasiveness in pancreatic cancers.
Collapse
Affiliation(s)
- Keisuke Taniuchi
- Department of Endoscopic Diagnostics and Therapeutics, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan; Department of Gastroenterology and Hepatology, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan.
| | - Mutsuo Furihata
- Department of Pathology, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan
| | - Toshiji Saibara
- Department of Gastroenterology and Hepatology, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan
| |
Collapse
|
14
|
Terauchi A, Timmons KM, Kikuma K, Pechmann Y, Kneussel M, Umemori H. Selective synaptic targeting of the excitatory and inhibitory presynaptic organizers FGF22 and FGF7. J Cell Sci 2014; 128:281-92. [PMID: 25431136 DOI: 10.1242/jcs.158337] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Specific formation of excitatory and inhibitory synapses is crucial for proper functioning of the brain. Fibroblast growth factor 22 (FGF22) and FGF7 are postsynaptic-cell-derived presynaptic organizers necessary for excitatory and inhibitory presynaptic differentiation, respectively, in the hippocampus. For the establishment of specific synaptic networks, these FGFs must localize to appropriate synaptic locations - FGF22 to excitatory and FGF7 to inhibitory postsynaptic sites. Here, we show that distinct motor and adaptor proteins contribute to intracellular microtubule transport of FGF22 and FGF7. Excitatory synaptic targeting of FGF22 requires the motor proteins KIF3A and KIF17 and the adaptor protein SAP102 (also known as DLG3). By contrast, inhibitory synaptic targeting of FGF7 requires the motor KIF5 and the adaptor gephyrin. Time-lapse imaging shows that FGF22 moves with SAP102, whereas FGF7 moves with gephyrin. These results reveal the basis of selective targeting of the excitatory and inhibitory presynaptic organizers that supports their different synaptogenic functions. Finally, we found that knockdown of SAP102 or PSD95 (also known as DLG4), which impairs the differentiation of excitatory synapses, alters FGF7 localization, suggesting that signals from excitatory synapses might regulate inhibitory synapse formation by controlling the distribution of the inhibitory presynaptic organizer.
Collapse
Affiliation(s)
- Akiko Terauchi
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Kendall M Timmons
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Koto Kikuma
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Yvonne Pechmann
- Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Matthias Kneussel
- Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Hisashi Umemori
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| |
Collapse
|
15
|
Smith R, Rathod RJ, Rajkumar S, Kennedy D. Nervous translation, do you get the message? A review of mRNPs, mRNA-protein interactions and translational control within cells of the nervous system. Cell Mol Life Sci 2014; 71:3917-37. [PMID: 24952431 PMCID: PMC11113408 DOI: 10.1007/s00018-014-1660-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/22/2014] [Accepted: 05/30/2014] [Indexed: 01/01/2023]
Abstract
In neurons, translation of a message RNA can occur metres away from its transcriptional origin and in normal cells this is orchestrated with perfection. The life of an mRNA will see it pass through multiple steps of processing in the nucleus and the cytoplasm before it reaches its final destination. Processing of mRNA is determined by a myriad of RNA-binding proteins in multi-protein complexes called messenger ribonucleoproteins; however, incorrect processing and delivery of mRNA can cause several human neurological disorders. This review takes us through the life of mRNA from the nucleus to its point of translation in the cytoplasm. The review looks at the various cis and trans factors that act on the mRNA and discusses their roles in different cells of the nervous system and human disorders.
Collapse
Affiliation(s)
- Ross Smith
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia,
| | | | | | | |
Collapse
|
16
|
Valenzuela JI, Jaureguiberry-Bravo M, Salas DA, Ramírez OA, Cornejo VH, Lu HE, Blanpied TA, Couve A. Transport along the dendritic endoplasmic reticulum mediates the trafficking of GABAB receptors. J Cell Sci 2014; 127:3382-95. [PMID: 24895402 DOI: 10.1242/jcs.151092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In neurons, secretory organelles within the cell body are complemented by the dendritic endoplasmic reticulum (ER) and Golgi outposts (GOPs), whose role in neurotransmitter receptor trafficking is poorly understood. γ-aminobutyric acid (GABA) type B metabotropic receptors (GABABRs) regulate the efficacy of synaptic transmission throughout the brain. Their plasma membrane availability is controlled by mechanisms involving an ER retention motif and assembly-dependent ER export. Thus, they constitute an ideal molecular model to study ER trafficking, but the extent to which the dendritic ER participates in GABABR biosynthesis has not been thoroughly explored. Here, we show that GABAB1 localizes preferentially to the ER in dendrites and moves long distances within this compartment. Not only diffusion but also microtubule and dynein-dependent mechanisms control dendritic ER transport. GABABRs insert throughout the somatodendritic plasma membrane but dendritic post-ER carriers containing GABABRs do not fuse selectively with GOPs. This study furthers our understanding of the spatial selectivity of neurotransmitter receptors for dendritic organelles.
Collapse
Affiliation(s)
- José I Valenzuela
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Matías Jaureguiberry-Bravo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Daniela A Salas
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Omar A Ramírez
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Program of Anatomy and Development, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Víctor H Cornejo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Hsiangmin E Lu
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrés Couve
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| |
Collapse
|
17
|
A non-canonical initiation site is required for efficient translation of the dendritically localized Shank1 mRNA. PLoS One 2014; 9:e88518. [PMID: 24533096 PMCID: PMC3922875 DOI: 10.1371/journal.pone.0088518] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/06/2014] [Indexed: 11/19/2022] Open
Abstract
Local protein synthesis in dendrites enables neurons to selectively change the protein complement of individual postsynaptic sites. Though it is generally assumed that this mechanism requires tight translational control of dendritically transported mRNAs, it is unclear how translation of dendritic mRNAs is regulated. We have analyzed here translational control elements of the dendritically localized mRNA coding for the postsynaptic scaffold protein Shank1. In its 5′ region, the human Shank1 mRNA exhibits two alternative translation initiation sites (AUG+1 and AUG+214), three canonical upstream open reading frames (uORFs1-3) and a high GC content. In reporter assays, fragments of the 5′UTR with high GC content inhibit translation, suggesting a contribution of secondary structures. uORF3 is most relevant to translation control as it overlaps with the first in frame start codon (AUG+1), directing translation initiation to the second in frame start codon (AUG+214). Surprisingly, our analysis points to an additional uORF initiated at a non-canonical ACG start codon. Mutation of this start site leads to an almost complete loss of translation initiation at AUG+1, demonstrating that this unconventional uORF is required for Shank1 synthesis. Our data identify a novel mechanism whereby initiation at a non-canonical site allows for translation of the main Shank1 ORF despite a highly structured 5′UTR.
Collapse
|
18
|
Spatiotemporal intracellular dynamics of neurotrophin and its receptors. Implications for neurotrophin signaling and neuronal function. Handb Exp Pharmacol 2014; 220:33-65. [PMID: 24668469 DOI: 10.1007/978-3-642-45106-5_3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neurons possess a polarized morphology specialized to contribute to neuronal networks, and this morphology imposes an important challenge for neuronal signaling and communication. The physiology of the network is regulated by neurotrophic factors that are secreted in an activity-dependent manner modulating neuronal connectivity. Neurotrophins are a well-known family of neurotrophic factors that, together with their cognate receptors, the Trks and the p75 neurotrophin receptor, regulate neuronal plasticity and survival and determine the neuronal phenotype in healthy and regenerating neurons. Is it now becoming clear that neurotrophin signaling and vesicular transport are coordinated to modify neuronal function because disturbances of vesicular transport mechanisms lead to disturbed neurotrophin signaling and to diseases of the nervous system. This chapter summarizes our current understanding of how the regulated secretion of neurotrophin, the distribution of neurotrophin receptors in different locations of neurons, and the intracellular transport of neurotrophin-induced signaling in distal processes are achieved to allow coordinated neurotrophin signaling in the cell body and axons.
Collapse
|
19
|
Epstein I, Tushev G, Will TJ, Vlatkovic I, Cajigas IJ, Schuman EM. Alternative polyadenylation and differential expression of Shank mRNAs in the synaptic neuropil. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130137. [PMID: 24298140 DOI: 10.1098/rstb.2013.0137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The stability and dynamics of synapses rely on tight regulation of the synaptic proteome. Shank proteins, encoded by the three genes Shank1, Shank2 and Shank3 are scaffold molecules in the postsynaptic density of excitatory neurons that contribute to activity-dependent neuronal signalling. Mutations in the Shank genes are associated with neurological diseases. Using state-of-the-art technologies, we investigated the levels of expression of the Shank family messenger RNAs (mRNAs) within the synaptic neuropil of the rat hippocampus. We detected all three Shank transcripts in the neuropil of CA1 pyramidal neurons. We found Shank1 to be the most abundantly expressed among the three Shank mRNA homologues. We also examined the turnover of Shank mRNAs and predict the half-lives of Shank1, Shank2 and Shank3 mRNAs to be 18-28 h. Using 3'-end sequencing, we identified novel 3' ends for the Shank1 and Shank2 3' untranslated regions (3' UTRs) that may contribute to the diversity of alternative polyadenylation (APA) for the Shank transcripts. Our findings consolidate the view that the Shank molecules play a central role at the postsynaptic density. This study may shed light on synaptopathologies associated with disruption of local protein synthesis, perhaps linked to mutations in mRNA 3' UTRs or inappropriate 3' end processing.
Collapse
Affiliation(s)
- Irina Epstein
- Max Planck Institute for Brain Research, , Max-von-Laue Strasse 4, Frankfurt am Main 60438, Germany
| | | | | | | | | | | |
Collapse
|
20
|
Kim TK, Sul JY, Helmfors H, Langel U, Kim J, Eberwine J. Dendritic glutamate receptor mRNAs show contingent local hotspot-dependent translational dynamics. Cell Rep 2013; 5:114-25. [PMID: 24075992 DOI: 10.1016/j.celrep.2013.08.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 07/24/2013] [Accepted: 08/14/2013] [Indexed: 11/16/2022] Open
Abstract
Protein synthesis in neuronal dendrites underlies long-term memory formation in the brain. Local translation of reporter mRNAs has demonstrated translation in dendrites at focal points called translational hotspots. Various reports have shown that hundreds to thousands of mRNAs are localized to dendrites, yet the dynamics of translation of multiple dendritic mRNAs has remained elusive. Here, we show that the protein translational activities of two dendritically localized mRNAs are spatiotemporally complex but constrained by the translational hotspots in which they are colocalized. Cotransfection of glutamate receptor 2 (GluR2) and GluR4 mRNAs (engineered to encode different fluorescent proteins) into rat hippocampal neurons demonstrates a heterogeneous distribution of translational hotspots for the two mRNAs along dendrites. Stimulation with s-3,5-dihydroxy-phenylglycine modifies the translational dynamics of both of these RNAs in a complex saturable manner. These results suggest that the translational hotspot is a primary structural regulator of the simultaneous yet differential translation of multiple mRNAs in the neuronal dendrite.
Collapse
Affiliation(s)
- Tae Kyung Kim
- Department of Pharmacology, Perelman School of Medicine, Philadelphia, PA 19104-6084, USA
| | | | | | | | | | | |
Collapse
|
21
|
Mameza MG, Dvoretskova E, Bamann M, Hönck HH, Güler T, Boeckers TM, Schoen M, Verpelli C, Sala C, Barsukov I, Dityatev A, Kreienkamp HJ. SHANK3 gene mutations associated with autism facilitate ligand binding to the Shank3 ankyrin repeat region. J Biol Chem 2013; 288:26697-708. [PMID: 23897824 DOI: 10.1074/jbc.m112.424747] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Shank/ProSAP proteins are major scaffold proteins of the postsynaptic density; mutations in the human SHANK3 gene are associated with intellectual disability or autism spectrum disorders. We have analyzed the functional relevance of several SHANK3 missense mutations affecting the N-terminal portion of the protein by expression of wild-type and mutant Shank3 in cultured neurons and by binding assays in heterologous cells. Postsynaptic targeting of recombinant Shank3 was unaltered. In electrophysiological experiments, both wild-type and L68P mutant forms of Shank3 were equally effective in restoring synaptic function after knockdown of endogenous Shank3. We observed that several mutations affected binding to interaction partners of the Shank3 ankyrin repeat region. One of these mutations, L68P, improved binding to both ligands. Leu-68 is located N-terminal to the ankyrin repeats, in a highly conserved region that we identify here as a novel domain termed the Shank/ProSAP N-terminal (SPN) domain. We show that the SPN domain interacts with the ankyrin repeats in an intramolecular manner, thereby restricting access of either Sharpin or α-fodrin. The L68P mutation disrupts this blockade, thus exposing the Shank3 ankyrin repeat region to its ligands. Our data identify a new type of regulation of Shank proteins and suggest that mutations in the SHANK3 gene do not necessarily induce a loss of function, but may represent a gain of function with respect to specific interaction partners.
Collapse
Affiliation(s)
- Marie Germaine Mameza
- From the Institut für Humangenetik, Universitätskrankenhaus Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Leal G, Comprido D, Duarte CB. BDNF-induced local protein synthesis and synaptic plasticity. Neuropharmacology 2013; 76 Pt C:639-56. [PMID: 23602987 DOI: 10.1016/j.neuropharm.2013.04.005] [Citation(s) in RCA: 429] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/25/2013] [Accepted: 04/03/2013] [Indexed: 12/16/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptic transmission and long-term potentiation (LTP) in the hippocampus and in other brain regions, playing a role in the formation of certain forms of memory. The effects of BDNF in LTP are mediated by TrkB (tropomyosin-related kinase B) receptors, which are known to be coupled to the activation of the Ras/ERK, phosphatidylinositol 3-kinase/Akt and phospholipase C-γ (PLC-γ) pathways. The role of BDNF in LTP is best studied in the hippocampus, where the neurotrophin acts at pre- and post-synaptic levels. Recent studies have shown that BDNF regulates the transport of mRNAs along dendrites and their translation at the synapse, by modulating the initiation and elongation phases of protein synthesis, and by acting on specific miRNAs. Furthermore, the effect of BDNF on transcription regulation may further contribute to long-term changes in the synaptic proteome. In this review we discuss the recent progress in understanding the mechanisms contributing to the short- and long-term regulation of the synaptic proteome by BDNF, and the role in synaptic plasticity, which is likely to influence learning and memory formation. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
Collapse
Affiliation(s)
- Graciano Leal
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | | | | |
Collapse
|
23
|
Zivraj KH, Rehbein M, Ölschläger-Schütt J, Schob C, Falley K, Buck F, Schweizer M, Schepis A, Kremmer E, Richter D, Kreienkamp HJ, Kindler S. The RNA-binding protein MARTA2 regulates dendritic targeting of MAP2 mRNAs in rat neurons. J Neurochem 2013; 124:670-84. [PMID: 23121659 DOI: 10.1111/jnc.12079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/08/2012] [Accepted: 10/13/2012] [Indexed: 11/30/2022]
Abstract
Dendritic targeting of mRNAs encoding the microtubule-associated protein 2 (MAP2) in neurons involves a cis-acting dendritic targeting element. Two rat brain proteins, MAP2-RNA trans-acting protein (MARTA)1 and MARTA2, bind to the cis-element with both high affinity and specificity. In this study, affinity-purified MARTA2 was identified as orthologue of human far-upstream element binding protein 3. In neurons, it resides in somatodendritic granules and dendritic spines and associates with MAP2 mRNAs. Expression of a dominant-negative variant of MARTA2 disrupts dendritic targeting of endogenous MAP2 mRNAs, while not noticeably altering the level and subcellular distribution of polyadenylated mRNAs as a whole. Finally, MAP2 transcripts associate with the microtubule-based motor KIF5 and inhibition of KIF5, but not cytoplasmic dynein function disrupts extrasomatic trafficking of MAP2 mRNA granules. Thus, in neurons MARTA2 appears to represent a key trans-acting factor involved in KIF5-mediated dendritic targeting of MAP2 mRNAs.
Collapse
Affiliation(s)
- Krishna H Zivraj
- Institute for Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Charalambous DC, Pasciuto E, Mercaldo V, Pilo Boyl P, Munck S, Bagni C, Santama N. KIF1Bβ transports dendritically localized mRNPs in neurons and is recruited to synapses in an activity-dependent manner. Cell Mol Life Sci 2013; 70:335-56. [PMID: 22945799 PMCID: PMC11113723 DOI: 10.1007/s00018-012-1108-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 07/17/2012] [Accepted: 07/24/2012] [Indexed: 12/15/2022]
Abstract
KIF1Bβ is a kinesin-like, microtubule-based molecular motor protein involved in anterograde axonal vesicular transport in vertebrate and invertebrate neurons. Certain KIF1Bβ isoforms have been implicated in different forms of human neurodegenerative disease, with characterization of their functional integration and regulation in the context of synaptic signaling still ongoing. Here, we characterize human KIF1Bβ (isoform NM015074), whose expression we show to be developmentally regulated and elevated in cortical areas of the CNS (including the motor cortex), in the hippocampus, and in spinal motor neurons. KIF1Bβ localizes to the cell body, axon, and dendrites, overlapping with synaptic-vesicle and postsynaptic-density structures. Correspondingly, in purified cortical synaptoneurosomes, KIF1Bβ is enriched in both pre- and postsynaptic structures, forming detergent-resistant complexes. Interestingly, KIF1Bβ forms RNA-protein complexes, containing the dendritically localized Arc and Calmodulin mRNAs, proteins previously shown to be part of RNA transport granules such as Purα, FMRP and FXR2P, and motor protein KIF3A, as well as Calmodulin. The interaction between KIF1Bβ and Calmodulin is Ca(+2)-dependent and takes place through a domain mapped at the carboxy-terminal tail of the motor. Live imaging of cortical neurons reveals active movement by KIF1Bβ at dendritic processes, suggesting that it mediates the transport of dendritically localized mRNAs. Finally, we show that synaptic recruitment of KIF1Bβ is activity-dependent and increased by stimulation of metabotropic or ionotropic glutamate receptors. The activity-dependent synaptic recruitment of KIF1Bβ, its interaction with Ca(2+) sensor Calmodulin, and its new role as a dendritic motor of ribonucleoprotein complexes provide a novel basis for understanding the concerted co-ordination of motor protein mobilization and synaptic signaling pathways.
Collapse
Affiliation(s)
- Despina C. Charalambous
- Department of Biological Sciences, University of Cyprus, University Avenue 1, 1678 Nicosia, Cyprus
| | - Emanuela Pasciuto
- VIB Center for Biology of Disease, Katholieke Universiteit Leuven, Heresraat 49, 3000 Leuven, Belgium
| | - Valentina Mercaldo
- VIB Center for Biology of Disease, Katholieke Universiteit Leuven, Heresraat 49, 3000 Leuven, Belgium
- Present Address: Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Pietro Pilo Boyl
- VIB Center for Biology of Disease, Katholieke Universiteit Leuven, Heresraat 49, 3000 Leuven, Belgium
- Present Address: Institute of Genetics, University of Bonn, Karlrobert-Kreiten Str. 13, 53115 Bonn, Germany
| | - Sebastian Munck
- VIB Center for Biology of Disease, Katholieke Universiteit Leuven, Heresraat 49, 3000 Leuven, Belgium
| | - Claudia Bagni
- VIB Center for Biology of Disease, Katholieke Universiteit Leuven, Heresraat 49, 3000 Leuven, Belgium
- Department of Biomedicine and Prevention, Faculty of Medicine, University of Rome Tor Vergata, Via Montpellier 1, 00100 Rome, Italy
| | - Niovi Santama
- Department of Biological Sciences, University of Cyprus, University Avenue 1, 1678 Nicosia, Cyprus
| |
Collapse
|
25
|
Swanger SA, Bassell GJ. Dendritic protein synthesis in the normal and diseased brain. Neuroscience 2012; 232:106-27. [PMID: 23262237 DOI: 10.1016/j.neuroscience.2012.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/21/2012] [Accepted: 12/01/2012] [Indexed: 01/25/2023]
Abstract
Synaptic activity is a spatially limited process that requires a precise, yet dynamic, complement of proteins within the synaptic micro-domain. The maintenance and regulation of these synaptic proteins is regulated, in part, by local mRNA translation in dendrites. Protein synthesis within the postsynaptic compartment allows neurons tight spatial and temporal control of synaptic protein expression, which is critical for proper functioning of synapses and neural circuits. In this review, we discuss the identity of proteins synthesized within dendrites, the receptor-mediated mechanisms regulating their synthesis, and the possible roles for these locally synthesized proteins. We also explore how our current understanding of dendritic protein synthesis in the hippocampus can be applied to new brain regions and to understanding the pathological mechanisms underlying varied neurological diseases.
Collapse
Affiliation(s)
- S A Swanger
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - G J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
26
|
Valdés V, Valenzuela JI, Salas DA, Jaureguiberry-Bravo M, Otero C, Thiede C, Schmidt CF, Couve A. Endoplasmic reticulum sorting and kinesin-1 command the targeting of axonal GABAB receptors. PLoS One 2012; 7:e44168. [PMID: 22952914 PMCID: PMC3428321 DOI: 10.1371/journal.pone.0044168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/30/2012] [Indexed: 12/17/2022] Open
Abstract
In neuronal cells the intracellular trafficking machinery controls the availability of neurotransmitter receptors at the plasma membrane, which is a critical determinant of synaptic strength. Metabotropic γ amino-butyric acid (GABA) type B receptors (GABABRs) are neurotransmitter receptors that modulate synaptic transmission by mediating the slow and prolonged responses to GABA. GABABRs are obligatory heteromers constituted by two subunits, GABABR1 and GABABR2. GABABR1a and GABABR1b are the most abundant subunit variants. GABABR1b is located in the somatodendritic domain whereas GABABR1a is additionally targeted to the axon. Sushi domains located at the N-terminus of GABABR1a constitute the only difference between both variants and are necessary and sufficient for axonal targeting. The precise targeting machinery and the organelles involved in sorting and transport have not been described. Here we demonstrate that GABABRs require the Golgi apparatus for plasma membrane delivery but that axonal sorting and targeting of GABABR1a operate in a pre-Golgi compartment. In the axon GABABR1a subunits are enriched in the endoplasmic reticulum (ER), and their dynamic behavior and colocalization with other secretory organelles like the ER-to-Golgi intermediate compartment (ERGIC) suggest that they employ a local secretory route. The transport of axonal GABABR1a is microtubule-dependent and kinesin-1, a molecular motor of the kinesin family, determines axonal localization. Considering that progression of GABABRs through the secretory pathway is regulated by an ER retention motif our data contribute to understand the role of the axonal ER in non-canonical sorting and targeting of neurotransmitter receptors.
Collapse
Affiliation(s)
- Viviana Valdés
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - José Ignacio Valenzuela
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Daniela A. Salas
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Matías Jaureguiberry-Bravo
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- School of Biochemistry, Faculty of Biological Science, Universidad Andrés Bello, Santiago, Chile
| | - Carolina Otero
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christina Thiede
- Georg-August-Universität, Fakultät für Physik, Drittes Physikalisches Institut-Biophysik, Göttingen, Germany
| | - Christoph F. Schmidt
- Georg-August-Universität, Fakultät für Physik, Drittes Physikalisches Institut-Biophysik, Göttingen, Germany
| | - Andrés Couve
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- * E-mail:
| |
Collapse
|
27
|
Chang YF, Chou HJ, Yen YC, Chang HW, Hong YR, Huang HW, Tseng CN. Agrin induces association of Chrna1 mRNA and nicotinic acetylcholine receptor in C2C12 myotubes. FEBS Lett 2012; 586:3111-6. [PMID: 22884571 DOI: 10.1016/j.febslet.2012.07.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 07/05/2012] [Accepted: 07/20/2012] [Indexed: 11/30/2022]
Abstract
In the mammalian central nervous system transcripts of certain synaptic components are localized near the synapse, allowing for rapid regulation of protein levels. Here we test whether an mRNA localization mechanism also exists in the postsynaptic specialization induced by agrin in C2C12 myotubes. RT-PCR showed that Chrna1 was co-purified with nicotinic acetylcholine receptor (AChR) isolated by affinity column or by ultracentrifugation. In addition, Stau1 was found to interact with Chrna1 mRNA, and knocking down of Stau1 by RNAi resulted in defective AChR clustering. These results suggest that mRNA localization also participates in the formation of mammalian neuromuscular junction (NMJ).
Collapse
Affiliation(s)
- Yung-Fu Chang
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung City 807, Taiwan
| | | | | | | | | | | | | |
Collapse
|
28
|
Vidal RL, Fuentes P, Valenzuela JI, Alvarado-Diaz CP, Ramírez OA, Kukuljan M, Couve A. RNA interference of Marlin-1/Jakmip1 results in abnormal morphogenesis and migration of cortical pyramidal neurons. Mol Cell Neurosci 2012; 51:1-11. [DOI: 10.1016/j.mcn.2012.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 07/04/2012] [Accepted: 07/17/2012] [Indexed: 10/28/2022] Open
|
29
|
Ting JT, Peça J, Feng G. Functional consequences of mutations in postsynaptic scaffolding proteins and relevance to psychiatric disorders. Annu Rev Neurosci 2012; 35:49-71. [PMID: 22540979 DOI: 10.1146/annurev-neuro-062111-150442] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Functional studies on postsynaptic scaffolding proteins at excitatory synapses have revealed a plethora of important roles for synaptic structure and function. In addition, a convergence of recent in vivo functional evidence together with human genetics data strongly suggest that mutations in a variety of these postsynaptic scaffolding proteins may contribute to the etiology of diverse human psychiatric disorders such as schizophrenia, autism spectrum disorders, and obsessive-compulsive spectrum disorders. Here we review the most recent evidence for several key postsynaptic scaffolding protein families and explore how mouse genetics and human genetics have intersected to advance our knowledge concerning the contributions of these important players to complex brain function and dysfunction.
Collapse
Affiliation(s)
- Jonathan T Ting
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
| | | | | |
Collapse
|
30
|
Baez MV, Luchelli L, Maschi D, Habif M, Pascual M, Thomas MG, Boccaccio GL. Smaug1 mRNA-silencing foci respond to NMDA and modulate synapse formation. ACTA ACUST UNITED AC 2012; 195:1141-57. [PMID: 22201125 PMCID: PMC3246892 DOI: 10.1083/jcb.201108159] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
S-foci, the first reported mRNA-silencing foci specific to neurons, may control local mRNA translation in response to NMDA receptor stimulation and synaptic plasticity. Mammalian Smaug1/Samd4A is a translational repressor. Here we show that Smaug1 forms mRNA-silencing foci located at postsynapses of hippocampal neurons. These structures, which we have named S-foci, are distinct from P-bodies, stress granules, or other neuronal RNA granules hitherto described, and are the first described mRNA-silencing foci specific to neurons. RNA binding was not required for aggregation, which indicates that S-foci formation is not a consequence of mRNA silencing. N-methyl-d-aspartic acid (NMDA) receptor stimulation provoked a rapid and reversible disassembly of S-foci, transiently releasing transcripts (the CaMKIIα mRNA among others) to allow their translation. Simultaneously, NMDA triggered global translational silencing, which suggests the specific activation of Smaug1-repressed transcripts. Smaug1 is expressed during synaptogenesis, and Smaug1 knockdown affected the number and size of synapses, and also provoked an impaired response to repetitive depolarizing stimuli, as indicated by a reduced induction of Arc/Arg3.1. Our results suggest that S-foci control local translation, specifically responding to NMDA receptor stimulation and affecting synaptic plasticity.
Collapse
|
31
|
Dendritic mRNA targeting and translation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:285-305. [PMID: 22351061 DOI: 10.1007/978-3-7091-0932-8_13] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Selective targeting of specific mRNAs into neuronal dendrites and their locally regulated translation at particular cell contact sites contribute to input-specific synaptic plasticity. Thus, individual synapses become decision-making units, which control gene expression in a spatially restricted and nucleus-independent manner. Dendritic targeting of mRNAs is achieved by active, microtubule-dependent transport. For this purpose, mRNAs are packaged into large ribonucleoprotein (RNP) particles containing an array of trans-acting RNA-binding proteins. These are attached to molecular motors, which move their RNP cargo into dendrites. A variety of proteins may be synthesized in dendrites, including signalling and scaffold proteins of the synapse and neurotransmitter receptors. In some cases, such as the alpha subunit of the calcium/calmodulin-dependent protein kinase II (αCaMKII) and the activity-regulated gene of 3.1 kb (Arg3.1, also referred to as activity-regulated cDNA, Arc), their local synthesis at synapses can modulate long-term changes in synaptic efficiency. Local dendritic translation is regulated by several signalling cascades including Akt/mTOR and Erk/MAP kinase pathways, which are triggered by synaptic activity. More recent findings show that miRNAs also play an important role in protein synthesis at synapses. Disruption of local translation control at synapses, as observed in the fragile X syndrome (FXS) and its mouse models and possibly also in autism spectrum disorders, interferes with cognitive abilities in mice and men.
Collapse
|
32
|
Scaffold proteins at the postsynaptic density. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:29-61. [PMID: 22351050 DOI: 10.1007/978-3-7091-0932-8_2] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Scaffold proteins are abundant and essential components of the postsynaptic density (PSD). They play a major role in many synaptic functions including the trafficking, anchoring, and clustering of glutamate receptors and adhesion molecules. Moreover, they link postsynaptic receptors with their downstream signaling proteins and regulate the dynamics of cytoskeletal structures. By definition, PSD scaffold proteins do not have intrinsic enzymatic activities but are formed by modular and specific domains deputed to form large protein networks. Here, we will discuss the latest findings regarding the structure and functions of major PSD scaffold proteins. Given that scaffold proteins are central components of PSD architecture, it is not surprising that deletion or mutations in their human genes cause severe neuropsychiatric disorders including autism, mental retardation, and schizophrenia. Thus, their dynamic organization and regulation are directly correlated with the essential structure of the PSD and the normal physiology of neuronal synapses.
Collapse
|
33
|
Kunde SA, Musante L, Grimme A, Fischer U, Muller E, Wanker EE, Kalscheuer VM. The X-chromosome-linked intellectual disability protein PQBP1 is a component of neuronal RNA granules and regulates the appearance of stress granules. Hum Mol Genet 2011; 20:4916-31. [DOI: 10.1093/hmg/ddr430] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
34
|
Gagnon JA, Mowry KL. Molecular motors: directing traffic during RNA localization. Crit Rev Biochem Mol Biol 2011; 46:229-39. [PMID: 21476929 DOI: 10.3109/10409238.2011.572861] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RNA localization, the enrichment of RNA in a specific subcellular region, is a mechanism for the establishment and maintenance of cellular polarity in a variety of systems. Ultimately, this results in a universal method for spatially restricting gene expression. Although the consequences of RNA localization are well-appreciated, many of the mechanisms that are responsible for carrying out polarized transport remain elusive. Several recent studies have illuminated the roles that molecular motor proteins play in the process of RNA localization. These studies have revealed complex mechanisms in which the coordinated action of one or more motor proteins can act at different points in the localization process to direct RNAs to their final destination. In this review, we discuss recent findings from several different systems in an effort to clarify pathways and mechanisms that control the directed movement of RNA.
Collapse
Affiliation(s)
- James A Gagnon
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, USA
| | | |
Collapse
|
35
|
Wischmeijer A, Magini P, Giorda R, Gnoli M, Ciccone R, Cecconi L, Franzoni E, Mazzanti L, Romeo G, Zuffardi O, Seri M. Olfactory Receptor-Related Duplicons Mediate a Microdeletion at 11q13.2q13.4 Associated with a Syndromic Phenotype. Mol Syndromol 2010; 1:176-184. [PMID: 21373257 DOI: 10.1159/000322054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2010] [Indexed: 11/19/2022] Open
Abstract
By array-CGH, we identified a cryptic deletion of about 3.4 Mb involving the chromosomal region 11q13.2q13.4 in a child with speech and developmental delay. Highly homologous segmental duplications related to the well-known olfactory receptor (OR)-containing clusters at 8p and 4p are located at the breakpoints of the imbalance and may be involved in its occurrence. Although these structural features are known to promote recurrent chromosomal rearrangements and previous studies had included the 11q13.2q13.4 deletion region among those considered potentially more unstable, neither deletions nor duplications of this region had been reported until now. Among the deleted genes, SHANK2 might play a role in the phenotype of the patient since it encodes a postsynaptic scaffolding protein similar to SHANK3, whose haploinsufficiency is a well-known cause of severe speech delay and autistic-like behavior, and recently deletions and mutations of SHANK2 have been described in patients with an autistic spectrum disorder or mental retardation.
Collapse
|
36
|
Lammich S, Buell D, Zilow S, Ludwig AK, Nuscher B, Lichtenthaler SF, Prinzen C, Fahrenholz F, Haass C. Expression of the anti-amyloidogenic secretase ADAM10 is suppressed by its 5'-untranslated region. J Biol Chem 2010; 285:15753-60. [PMID: 20348102 DOI: 10.1074/jbc.m110.110742] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteolytic processing of the amyloid precursor protein by alpha-secretase prevents formation of the amyloid beta-peptide (Abeta), which is the main constituent of amyloid plaques in brains of Alzheimer disease (AD) patients. alpha-Secretase activity is decreased in AD, and overexpression of the alpha-secretase ADAM10 (a disintegrin and metalloprotease 10) in an AD animal model prevents amyloid pathology. ADAM10 has a 444-nucleotide-long, very GC-rich 5'-untranslated region (5'-UTR) with two upstream open reading frames. Because similar properties of 5'-UTRs are found in transcripts of many genes, which are regulated by translational control mechanisms, we asked whether ADAM10 expression is translationally controlled by its 5'-UTR. We demonstrate that the 5'-UTR of ADAM10 represses the rate of ADAM10 translation. In the absence of the 5'-UTR, we observed a significant increase of ADAM10 protein levels in HEK293 cells, whereas mRNA levels were not changed. Moreover, the 5'-UTR of ADAM10 inhibits translation of a luciferase reporter in an in vitro transcription/translation assay. Successive deletion of the first half of the ADAM10 5'-UTR revealed a striking increase in ADAM10 protein expression in HEK293 cells, suggesting that this part of the 5'-UTR contains inhibitory elements for translation. Moreover, we detect an enhanced alpha-secretase activity and consequently reduced Abeta levels in the conditioned medium of HEK293 cells expressing both amyloid precursor protein and a 5'-UTR-ADAM10 deletion construct lacking the first half of the 5'-UTR. Thus, we provide evidence that the 5'-UTR of ADAM10 may have an important role for post-transcriptional regulation of ADAM10 expression and consequently Abeta production.
Collapse
Affiliation(s)
- Sven Lammich
- German Center for Neurodegenerative Diseases (DZNE) and Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, 80336 Munich, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Schütt J, Falley K, Richter D, Kreienkamp HJ, Kindler S. Fragile X mental retardation protein regulates the levels of scaffold proteins and glutamate receptors in postsynaptic densities. J Biol Chem 2009; 284:25479-87. [PMID: 19640847 DOI: 10.1074/jbc.m109.042663] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Functional absence of fragile X mental retardation protein (FMRP) causes the fragile X syndrome, a hereditary form of mental retardation characterized by a change in dendritic spine morphology. The RNA-binding protein FMRP has been implicated in regulating postsynaptic protein synthesis. Here we have analyzed whether the abundance of scaffold proteins and neurotransmitter receptor subunits in postsynaptic densities (PSDs) is altered in the neocortex and hippocampus of FMRP-deficient mice. Whereas the levels of several PSD components are unchanged, concentrations of Shank1 and SAPAP scaffold proteins and various glutamate receptor subunits are altered in both adult and juvenile knock-out mice. With the exception of slightly increased hippocampal SAPAP2 mRNA levels in adult animals, altered postsynaptic protein concentrations do not correlate with similar changes in total and synaptic levels of corresponding mRNAs. Thus, loss of FMRP in neurons appears to mainly affect the translation and not the abundance of particular brain transcripts. Semi-quantitative analysis of RNA levels in FMRP immunoprecipitates showed that in the mouse brain mRNAs encoding PSD components, such as Shank1, SAPAP1-3, PSD-95, and the glutamate receptor subunits NR1 and NR2B, are associated with FMRP. Luciferase reporter assays performed in primary cortical neurons from knock-out and wild-type mice indicate that FMRP silences translation of Shank1 mRNAs via their 3'-untranslated region. Activation of metabotropic glutamate receptors relieves translational suppression. As Shank1 controls dendritic spine morphology, our data suggest that dysregulation of Shank1 synthesis may significantly contribute to the abnormal spine development and function observed in brains of fragile X syndrome patients.
Collapse
Affiliation(s)
- Janin Schütt
- Institute for Human Genetics, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | | | | | | | | |
Collapse
|
38
|
Kindler S, Dieterich DC, Schütt J, Sahin J, Karpova A, Mikhaylova M, Schob C, Gundelfinger ED, Kreienkamp HJ, Kreutz MR. Dendritic mRNA targeting of Jacob and N-methyl-d-aspartate-induced nuclear translocation after calpain-mediated proteolysis. J Biol Chem 2009; 284:25431-40. [PMID: 19608740 DOI: 10.1074/jbc.m109.022137] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Jacob is a recently identified plasticity-related protein that couples N-methyl-d-aspartate receptor activity to nuclear gene expression. An expression analysis by Northern blot and in situ hybridization shows that Jacob is almost exclusively present in brain, in particular in the cortex and the limbic system. Alternative splicing gives rise to multiple mRNA variants, all of which exhibit a prominent dendritic localization in the hippocampus. Functional analysis in primary hippocampal neurons revealed that a predominant cis-acting dendritic targeting element in the 3'-untranslated region of Jacob mRNAs is responsible for dendritic mRNA localization. In the mouse brain, Jacob transcripts are associated with both the fragile X mental retardation protein, a well described trans-acting factor regulating dendritic mRNA targeting and translation, and the kinesin family member 5C motor complex, which is known to mediate dendritic mRNA transport. Jacob is susceptible to rapid protein degradation in a Ca(2+)- and Calpain-dependent manner, and Calpain-mediated clipping of the myristoylated N terminus of Jacob is required for its nuclear translocation after N-methyl-d-aspartate receptor activation. Our data suggest that local synthesis in dendrites may be necessary to replenish dendritic Jacob pools after truncation of the N-terminal membrane anchor and concomitant translocation of Jacob to the nucleus.
Collapse
Affiliation(s)
- Stefan Kindler
- Institute of Human Genetics, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|