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Fratto E, Morelli M, Buonocore J, Quattrone A, Procopio R, Gagliardi M, Tinelli E, Fortunato F, Gambardella A. Hereditary Spastic Paraplegia Associated with Ultra-Rare Variant Enrichment Encompassing the SYNE1, CAPN1 and PGAP1 Genes. CEREBELLUM (LONDON, ENGLAND) 2024; 24:3. [PMID: 39641820 DOI: 10.1007/s12311-024-01758-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/18/2024] [Indexed: 12/07/2024]
Affiliation(s)
- E Fratto
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - Maurizio Morelli
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy.
| | - J Buonocore
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - A Quattrone
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - R Procopio
- Department of Medical and Surgical Sciences, Neuroscience Research Center, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - M Gagliardi
- Department of Medical and Surgical Sciences, Neuroscience Research Center, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - E Tinelli
- Department of Medical and Surgical Sciences, Institute of Neuroradiology, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - F Fortunato
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy
| | - A Gambardella
- Department of Medical and Surgical Sciences, Institute of Neurology, "Magna Graecia" University, Catanzaro, Calabria, Italy
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Kuwako KI, Suzuki S. Diverse Roles of the LINC Complex in Cellular Function and Disease in the Nervous System. Int J Mol Sci 2024; 25:11525. [PMID: 39519078 PMCID: PMC11545860 DOI: 10.3390/ijms252111525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2024] [Revised: 10/20/2024] [Accepted: 10/24/2024] [Indexed: 11/16/2024] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, which spans the nuclear envelope, physically connects nuclear components to the cytoskeleton and plays a pivotal role in various cellular processes, including nuclear positioning, cell migration, and chromosomal configuration. Studies have revealed that the LINC complex is essential for different aspects of the nervous system, particularly during development. The significance of the LINC complex in neural lineage cells is further corroborated by the fact that mutations in genes associated with the LINC complex have been implicated in several neurological diseases, including neurodegenerative and psychiatric disorders. In this review, we aimed to summarize the expanding knowledge of LINC complex-related neuronal functions and associated neurological diseases.
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Affiliation(s)
- Ken-ichiro Kuwako
- Department of Neural and Muscular Physiology, School of Medicine, Shimane University, 89-1 Enya-cho, Izumo-shi 693-8501, Shimane, Japan
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Catsburg LAE, Westra M, van Schaik AML, MacGillavry HD. Dynamics and nanoscale organization of the postsynaptic endocytic zone at excitatory synapses. eLife 2022; 11:74387. [PMID: 35072626 PMCID: PMC8813055 DOI: 10.7554/elife.74387] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/07/2021] [Indexed: 12/01/2022] Open
Abstract
At postsynaptic sites of neurons, a prominent clathrin-coated structure, the endocytic zone (EZ), controls the trafficking of glutamate receptors and is essential for synaptic plasticity. Despite its importance, little is known about how this clathrin structure is organized to mediate endocytosis. We used live-cell and super-resolution microscopy to reveal the dynamic organization of this poorly understood clathrin structure in rat hippocampal neurons. We found that a subset of endocytic proteins only transiently appeared at postsynaptic sites. In contrast, other proteins were persistently enriched and partitioned at the edge of the EZ. We found that uncoupling the EZ from the synapse led to the loss of most of these components, while disrupting interactions with the actin cytoskeleton or membrane did not alter EZ positioning. Finally, we found that plasticity-inducing stimuli promoted the reorganization of the EZ. We conclude that the EZ is a stable, highly organized molecular platform where components are differentially recruited and positioned to orchestrate the endocytosis of synaptic receptors.
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The why and how of sleep-dependent synaptic down-selection. Semin Cell Dev Biol 2021; 125:91-100. [PMID: 33712366 PMCID: PMC8426406 DOI: 10.1016/j.semcdb.2021.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/28/2021] [Accepted: 02/28/2021] [Indexed: 12/22/2022]
Abstract
Sleep requires that we disconnect from the environment, losing the ability to promptly respond to stimuli. There must be at least one essential function that justifies why we take this risk every day, and that function must depend on the brain being offline. We have proposed that this function is to renormalize synaptic weights after learning has led to a net increase in synaptic strength in many brain circuits. Without this renormalization, synaptic activity would become energetically too expensive and saturation would prevent new learning. There is converging evidence from molecular, electrophysiological, and ultrastructural experiments showing a net increase in synaptic strength after the major wake phase, and a net decline after sleep. The evidence also suggests that sleep-dependent renormalization is a smart process of synaptic down-selection, comprehensive and yet specific, which could explain the many beneficial effects of sleep on cognition. Recently, a key molecular mechanism that allows broad synaptic weakening during sleep was identified. Other mechanisms still being investigated should eventually explain how sleep can weaken most synapses but afford protection to some, including those directly activated by learning. That synaptic down-selection takes place during sleep is by now established; why it should take place during sleep has a plausible explanation; how it happens is still work in progress.
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Rathje M, Waxman H, Benoit M, Tammineni P, Leu C, Loebrich S, Nedivi E. Genetic variants in the bipolar disorder risk locus SYNE1 that affect CPG2 expression and protein function. Mol Psychiatry 2021; 26:508-523. [PMID: 30610203 PMCID: PMC6609516 DOI: 10.1038/s41380-018-0314-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 12/28/2022]
Abstract
Bipolar disorder (BD) is a common mood disorder characterized by recurrent episodes of mania and depression. Both genetic and environmental factors have been implicated in BD etiology, but the biological underpinnings remain elusive. Recently, genome-wide association studies (GWAS) of neuropsychiatric disorders have identified a risk locus for BD containing the SYNE1 gene, a large gene encoding multiple proteins. The BD association signal spans, almost exclusively, the part of SYNE1 encoding CPG2, a brain-specific protein localized to excitatory postsynaptic sites, where it regulates glutamate receptor internalization. Here we show that CPG2 protein levels are significantly decreased in postmortem brain tissue from BD patients, as compared to control subjects, as well as schizophrenia and depression patients. We identify genetic variants within the postmortem brains that map to the CPG2 promoter region, and show that they negatively affect gene expression. We also identify missense single nucleotide polymorphisms (SNPs) in CPG2 coding regions that affect CPG2 expression, localization, and synaptic function. Our findings link genetic variation in the CPG2 region of SYNE1 with a mechanism for glutamatergic synapse dysfunction that could underlie susceptibility to BD in some individuals. Few GWAS hits in human genetics for neuropsychiatric disorders to date have afforded such mechanistic clues. Further, the potential for genetic distinction of susceptibility to BD from other neuropsychiatric disorders with overlapping clinical traits holds promise for improved diagnostics and treatment of this devastating illness.
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Affiliation(s)
- Mette Rathje
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hannah Waxman
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marc Benoit
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Prasad Tammineni
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA,Stanley Center for Psychiatric Research, The Broad Institute of Harvard and MIT, Cambridge, MA, USA,Institute of Neurology, University College London, London, United Kingdom
| | - Sven Loebrich
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elly Nedivi
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Titlow J, Robertson F, Järvelin A, Ish-Horowicz D, Smith C, Gratton E, Davis I. Syncrip/hnRNP Q is required for activity-induced Msp300/Nesprin-1 expression and new synapse formation. J Cell Biol 2020; 219:133707. [PMID: 32040548 PMCID: PMC7055005 DOI: 10.1083/jcb.201903135] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 01/09/2023] Open
Abstract
Memory and learning involve activity-driven expression of proteins and cytoskeletal reorganization at new synapses, requiring posttranscriptional regulation of localized mRNA a long distance from corresponding nuclei. A key factor expressed early in synapse formation is Msp300/Nesprin-1, which organizes actin filaments around the new synapse. How Msp300 expression is regulated during synaptic plasticity is poorly understood. Here, we show that activity-dependent accumulation of Msp300 in the postsynaptic compartment of the Drosophila larval neuromuscular junction is regulated by the conserved RNA binding protein Syncrip/hnRNP Q. Syncrip (Syp) binds to msp300 transcripts and is essential for plasticity. Single-molecule imaging shows that msp300 is associated with Syp in vivo and forms ribosome-rich granules that contain the translation factor eIF4E. Elevated neural activity alters the dynamics of Syp and the number of msp300:Syp:eIF4E RNP granules at the synapse, suggesting that these particles facilitate translation. These results introduce Syp as an important early acting activity-dependent regulator of a plasticity gene that is strongly associated with human ataxias.
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Affiliation(s)
- Joshua Titlow
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Aino Järvelin
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford, UK.,Medical Research Council Lab for Molecular Cell Biology, University College London, London, UK
| | - Carlas Smith
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California Irvine, Irvine, CA
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, UK
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7
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Dendritic Spines in Alzheimer's Disease: How the Actin Cytoskeleton Contributes to Synaptic Failure. Int J Mol Sci 2020; 21:ijms21030908. [PMID: 32019166 PMCID: PMC7036943 DOI: 10.3390/ijms21030908] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by Aβ-driven synaptic dysfunction in the early phases of pathogenesis. In the synaptic context, the actin cytoskeleton is a crucial element to maintain the dendritic spine architecture and to orchestrate the spine’s morphology remodeling driven by synaptic activity. Indeed, spine shape and synaptic strength are strictly correlated and precisely governed during plasticity phenomena in order to convert short-term alterations of synaptic strength into long-lasting changes that are embedded in stable structural modification. These functional and structural modifications are considered the biological basis of learning and memory processes. In this review we discussed the existing evidence regarding the role of the spine actin cytoskeleton in AD synaptic failure. We revised the physiological function of the actin cytoskeleton in the spine shaping and the contribution of actin dynamics in the endocytosis mechanism. The internalization process is implicated in different aspects of AD since it controls both glutamate receptor membrane levels and amyloid generation. The detailed understanding of the mechanisms controlling the actin cytoskeleton in a unique biological context as the dendritic spine could pave the way to the development of innovative synapse-tailored therapeutic interventions and to the identification of novel biomarkers to monitor synaptic loss in AD.
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Li W, Yang Y, Luo B, Zhang Y, Song X, Li M, Lv L. Association of SYNE1 locus with bipolar disorder in Chinese population. Hereditas 2019; 156:19. [PMID: 31236099 PMCID: PMC6580462 DOI: 10.1186/s41065-019-0095-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/11/2019] [Indexed: 01/08/2023] Open
Abstract
Objectives Genome-wide association studies (GWAS) suggest that rs9371601 in the SYNE1 gene is a risk SNP for bipolar disorder (BPD) in populations of European ancestry, but further replication analyses across distinct populations are needed. Methods We analyzed the association between rs9371601 and BPD in a Han Chinese sample of 1315 BPD cases and 1956 controls. Results We observed a significant association between rs9371601 and BPD in Han Chinese (p = 0.0121, OR = 0.859). However, further examinations revealed that the Europeans and Chinese subjects had different BPD risk alleles at the locus. We then found that rs9371601 had different “minor alleles” and distinct linkage disequilibrium (LD) patterns surrounding itself in Europeans and Han Chinese, which might be the explanation of the observed inconsistent association signals for this locus in different populations. Our explorative analyses of the biological impact of rs9371601 suggested that this SNP was significantly associated with the methylation of a CpG site (cg01844274, p = 5.05⨯10− 6) within SYNE1 in human dorsal lateral prefrontal cortex (DLPFC) tissues. Conclusions Our data confirms the association between rs9371601 and BPD, but the underlying biological mechanism remains to be fully elucidated in further studies. Electronic supplementary material The online version of this article (10.1186/s41065-019-0095-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenqiang Li
- 1Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan China.,2Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, Henan China
| | - Yongfeng Yang
- 1Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan China.,2Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, Henan China
| | - Binbin Luo
- 1Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan China.,2Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, Henan China
| | - Yan Zhang
- 1Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan China.,2Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, Henan China
| | - Xueqin Song
- 3The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan China
| | - Ming Li
- 4Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan China
| | - Luxian Lv
- 1Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan China.,2Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, Henan China.,5Henan Province People's Hospital, Zhengzhou, Henan China
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The Disease-Associated Chaperone FKBP51 Impairs Cognitive Function by Accelerating AMPA Receptor Recycling. eNeuro 2019; 6:eN-NWR-0242-18. [PMID: 30963102 PMCID: PMC6450497 DOI: 10.1523/eneuro.0242-18.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 01/18/2019] [Accepted: 02/01/2019] [Indexed: 12/22/2022] Open
Abstract
Increased expression of the FK506-binding protein 5 (FKBP5) gene has been associated with a number of diseases, but most prominently in connection to psychiatric illnesses. Many of these psychiatric disorders present with dementia and other cognitive deficits, but a direct connection between these issues and alterations in FKBP5 remains unclear. We generated a novel transgenic mouse to selectively overexpress FKBP5, which encodes the FKBP51 protein, in the corticolimbic system, which had no overt effects on gross body weight, motor ability, or general anxiety. Instead, we found that overexpression of FKBP51 impaired long-term depression (LTD) as well as spatial reversal learning and memory, suggesting a role in glutamate receptor regulation. Indeed, FKBP51 altered the association of heat-shock protein 90 (Hsp90) with AMPA receptors, which was accompanied by an accelerated rate of AMPA recycling. In this way, the chaperone system is critical in triage decisions for AMPA receptor trafficking. Imbalance in the chaperone system may manifest in impairments in both inhibitory learning and cognitive function. These findings uncover an unexpected and essential mechanism for learning and memory that is controlled by the psychiatric risk factor FKBP5.
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10
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Alpár A, Zahola P, Hanics J, Hevesi Z, Korchynska S, Benevento M, Pifl C, Zachar G, Perugini J, Severi I, Leitgeb P, Bakker J, Miklosi AG, Tretiakov E, Keimpema E, Arque G, Tasan RO, Sperk G, Malenczyk K, Máté Z, Erdélyi F, Szabó G, Lubec G, Palkovits M, Giordano A, Hökfelt TG, Romanov RA, Horvath TL, Harkany T. Hypothalamic CNTF volume transmission shapes cortical noradrenergic excitability upon acute stress. EMBO J 2018; 37:e100087. [PMID: 30209240 PMCID: PMC6213283 DOI: 10.15252/embj.2018100087] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 02/06/2023] Open
Abstract
Stress-induced cortical alertness is maintained by a heightened excitability of noradrenergic neurons innervating, notably, the prefrontal cortex. However, neither the signaling axis linking hypothalamic activation to delayed and lasting noradrenergic excitability nor the molecular cascade gating noradrenaline synthesis is defined. Here, we show that hypothalamic corticotropin-releasing hormone-releasing neurons innervate ependymal cells of the 3rd ventricle to induce ciliary neurotrophic factor (CNTF) release for transport through the brain's aqueductal system. CNTF binding to its cognate receptors on norepinephrinergic neurons in the locus coeruleus then initiates sequential phosphorylation of extracellular signal-regulated kinase 1 and tyrosine hydroxylase with the Ca2+-sensor secretagogin ensuring activity dependence in both rodent and human brains. Both CNTF and secretagogin ablation occlude stress-induced cortical norepinephrine synthesis, ensuing neuronal excitation and behavioral stereotypes. Cumulatively, we identify a multimodal pathway that is rate-limited by CNTF volume transmission and poised to directly convert hypothalamic activation into long-lasting cortical excitability following acute stress.
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Affiliation(s)
- Alán Alpár
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Péter Zahola
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - János Hanics
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Zsófia Hevesi
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary
| | - Solomiia Korchynska
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Marco Benevento
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Christian Pifl
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gergely Zachar
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - Jessica Perugini
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Ilenia Severi
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Patrick Leitgeb
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Joanne Bakker
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Andras G Miklosi
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gloria Arque
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Ramon O Tasan
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Katarzyna Malenczyk
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Zoltán Máté
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ferenc Erdélyi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gert Lubec
- Paracelsus Medical University, Salzburg, Austria
| | - Miklós Palkovits
- Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
- Human Brain Tissue Bank and Laboratory, Semmelweis University, Budapest, Hungary
| | - Antonio Giordano
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Tomas Gm Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Departments of Comparative Medicine and Neuroscience, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
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Identification of rare nonsynonymous variants in SYNE1/CPG2 in bipolar affective disorder. Psychiatr Genet 2018; 27:81-88. [PMID: 28178086 DOI: 10.1097/ypg.0000000000000166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Bipolar affective disorder (BPD) is a severe mood disorder with a prevalence of ∼1.5% in the population. The pathogenesis of BPD is poorly understood; however, a strong heritable component has been identified. Previous genome-wide association studies have indicated a region on 6q25, coding for the SYNE1 gene, which increases disease susceptibility. SYNE1 encodes the synaptic nuclear envelope protein-1, nesprin-1. A brain-specific splice variant of SYNE1, CPG2 encoding candidate plasticity gene 2, has been identified. The intronic single-nucleotide polymorphism with the strongest genome-wide significant association in BPD, rs9371601, is present in both SYNE1 and CPG2. METHODS We screened 937 BPD samples for genetic variation in SYNE1 exons 14-33, which covers the CPG2 region, using high-resolution melt analysis. In addition, we screened two regions of increased transcriptional activity, one of them proposed to be the CPG2 promoter region. RESULTS AND CONCLUSION We identified six nonsynonymous and six synonymous variants. We genotyped three rare nonsynonymous variants, rs374866393, rs148346599 and rs200629713, in a total of 1099 BPD samples and 1056 controls. Burden analysis of these rare variants did not show a significant association with BPD. However, nine patients are compound heterozygotes for variants in SYNE1/CPG2, suggesting that rare coding variants may contribute significantly towards the complex genetic architecture underlying BPD. Imputation analysis in our own whole-genome sequencing sample of 99 BPD individuals identified an additional eight risk variants in the CPG2 region of SYNE1.
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12
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Specific localization of nesprin-1-α2, the short isoform of nesprin-1 with a KASH domain, in developing, fetal and regenerating muscle, using a new monoclonal antibody. BMC Cell Biol 2016; 17:26. [PMID: 27350129 PMCID: PMC4924313 DOI: 10.1186/s12860-016-0105-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/20/2016] [Indexed: 01/25/2023] Open
Abstract
Background Nesprin-1-giant (1008kD) is a protein of the outer nuclear membrane that links nuclei to the actin cytoskeleton via amino-terminal calponin homology domains. The short nesprin-1 isoform, nesprin-1-α2, is present only in skeletal and cardiac muscle and several pathogenic mutations occur within it, but the functions of this short isoform without calponin homology domains are unclear. The aim of this study was to determine mRNA levels and protein localization of nesprin-1-α2 at different stages of muscle development in order to shed light on its functions. Results mRNA levels of all known nesprin-1 isoforms with a KASH domain were determined by quantitative PCR. The mRNA for the 111 kD muscle-specific short isoform, nesprin-1-α2, was not detected in pre-differentiation human myoblasts but was present at significant levels in multinucleate myotubes. We developed a monoclonal antibody against the unique amino-terminal sequence of nesprin-1-α2, enabling specific immunolocalization for the first time. Nesprin-1-α2 protein was undetectable in pre-differentiation myoblasts but appeared at the nuclear rim in post-mitotic, multinucleate myotubes and reached its highest levels in fetal muscle. In muscle from a Duchenne muscular dystrophy biopsy, nesprin-1-α2 protein was detected mainly in regenerating fibres expressing neonatal myosin. Nesprin-1-giant was present at all developmental stages, but was also highest in fetal and regenerating fibres. In fetal muscle, both isoforms were present in the cytoplasm, as well as at the nuclear rim. A pathogenic early stop codon (E7854X) in nesprin-1 caused reduced mRNA levels and loss of protein levels of both nesprin-1-giant and (unexpectedly) nesprin-1-α2, but did not affect myogenesis in vitro. Conclusions Nesprin-1-α2 mRNA and protein expression is switched on during myogenesis, alongside other known markers of muscle differentiation. The results show that nesprin-1-α2 is dynamically controlled and may be involved in some process occurring during early myofibre formation, such as re-positioning of nuclei.
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13
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Razafsky D, Hodzic D. Nuclear envelope: positioning nuclei and organizing synapses. Curr Opin Cell Biol 2015; 34:84-93. [PMID: 26079712 DOI: 10.1016/j.ceb.2015.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 05/28/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
The nuclear envelope plays an essential role in nuclear positioning within cells and tissues. This review highlights advances in understanding the mechanisms of nuclear positioning during skeletal muscle and central nervous system development. New findings, particularly about A-type lamins and Nesprin1, may link nuclear envelope integrity to synaptic integrity. Thus synaptic defects, rather than nuclear mispositioning, may underlie human pathologies associated with mutations of nuclear envelope proteins.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA.
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14
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Packard M, Jokhi V, Ding B, Ruiz-Cañada C, Ashley J, Budnik V. Nucleus to Synapse Nesprin1 Railroad Tracks Direct Synapse Maturation through RNA Localization. Neuron 2015; 86:1015-1028. [PMID: 25959729 DOI: 10.1016/j.neuron.2015.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 02/11/2015] [Accepted: 03/27/2015] [Indexed: 10/23/2022]
Abstract
An important mechanism underlying synapse development and plasticity is the localization of mRNAs that travel from the nucleus to synaptic sites. Here we demonstrate that the giant nuclear-associated Nesprin1 (dNesp1) forms striated F-actin-based filaments, which we dubbed "railroad tracks," that span from muscle nuclei to postsynaptic sites at the neuromuscular junction in Drosophila. These railroad tracks specifically wrap around immature boutons formed during development and in response to electrical activity. In the absence of dNesp1, mRNAs normally localized at postsynaptic sites are lacking and synaptic maturation is inhibited. This dNesp1 function does not depend on direct association of dNesp1 isoforms with the nuclear envelope. We also show that dNesp1 functions with an unconventional myosin, Myo1D, and that both dNesp1 and Myo1D are mutually required for their localization to immature boutons. These studies unravel a novel pathway directing the transport of mRNAs from the nucleus to postsynaptic sites during synaptic maturation. VIDEO ABSTRACT.
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Affiliation(s)
- Mary Packard
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA
| | - Vahbiz Jokhi
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA
| | - Baojin Ding
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA
| | - Catalina Ruiz-Cañada
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA
| | - James Ashley
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA
| | - Vivian Budnik
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01452, USA.
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15
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Razafsky D, Hodzic D. A variant of Nesprin1 giant devoid of KASH domain underlies the molecular etiology of autosomal recessive cerebellar ataxia type I. Neurobiol Dis 2015; 78:57-67. [PMID: 25843669 DOI: 10.1016/j.nbd.2015.03.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/21/2022] Open
Abstract
Nonsense mutations across the whole coding sequence of Syne1/Nesprin1 have been linked to autosomal recessive cerebellar ataxia Type I (ARCA1). However, nothing is known about the molecular etiology of this late-onset debilitating pathology. In this work, we report that Nesprin1 giant is specifically expressed in CNS tissues. We also identified a CNS-specific splicing event that leads to the abundant expression of a KASH-LESS variant of Nesprin1 giant (KLNes1g) in the cerebellum. KLNes1g displayed a noncanonical localization at glomeruli of cerebellar mossy fibers whereas Nesprin2 exclusively decorated the nuclear envelope of all cerebellar neurons. In immunogold electron microscopy, KLNes1g colocalized both with synaptic vesicles within mossy fibers and with dendritic membranes of cerebellar granule neurons. We further identified vesicle- and membrane-associated proteins in KLNes1g immunoprecipitates. Together, our results suggest that the loss of function of KLNes1g resulting from Nesprin1 nonsense mutations underlies the molecular etiology of ARCA1.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid, St Louis, MO 63110, USA
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid, St Louis, MO 63110, USA.
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16
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Hanley JG. Actin-dependent mechanisms in AMPA receptor trafficking. Front Cell Neurosci 2014; 8:381. [PMID: 25429259 PMCID: PMC4228833 DOI: 10.3389/fncel.2014.00381] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/24/2014] [Indexed: 11/22/2022] Open
Abstract
The precise regulation of AMPA receptor (AMPAR) number and subtype at the synapse is crucial for the regulation of excitatory neurotransmission, synaptic plasticity and the consequent formation of appropriate neural circuits for learning and memory. AMPAR trafficking involves the dynamic processes of exocytosis, endocytosis and endosomal recycling, all of which involve the actin cytoskeleton. The actin cytoskeleton is highly dynamic and highly regulated by an abundance of actin-binding proteins and upstream signaling pathways that modulate actin polymerization and depolymerization. Actin dynamics generate forces that manipulate membranes in the process of vesicle biogenesis, and also for propelling vesicles through the cytoplasm to reach their destination. In addition, trafficking mechanisms exploit more stable aspects of the actin cytoskeleton by using actin-based motor proteins to traffic vesicular cargo along actin filaments. Numerous studies have shown that actin dynamics are critical for AMPAR localization and function. The identification of actin-binding proteins that physically interact with AMPAR subunits, and research into their mode of action is starting to shed light on the mechanisms involved. Such proteins either regulate actin dynamics to modulate mechanical forces exerted on AMPAR-containing membranes, or associate with actin filaments to target or transport AMPAR-containing vesicles to specific subcellular regions. In addition, actin-regulatory proteins that do not physically interact with AMPARs may influence AMPAR trafficking by regulating the local actin environment in the dendritic spine.
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17
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Rajgor D, Mellad JA, Soong D, Rattner JB, Fritzler MJ, Shanahan CM. Mammalian microtubule P-body dynamics are mediated by nesprin-1. ACTA ACUST UNITED AC 2014; 205:457-75. [PMID: 24862572 PMCID: PMC4033771 DOI: 10.1083/jcb.201306076] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nesprins are a multi-isomeric family of spectrin-repeat (SR) proteins, predominantly known as nuclear envelope scaffolds. However, isoforms that function beyond the nuclear envelope remain poorly examined. Here, we characterize p50(Nesp1), a 50-kD isoform that localizes to processing bodies (PBs), where it acts as a microtubule-associated protein capable of linking mRNP complexes to microtubules. Overexpression of dominant-negative p50(Nesp1) caused Rck/p54, but not GW182, displacement from microtubules, resulting in reduced PB movement and cross talk with stress granules (SGs). These cells disassembled canonical SGs induced by sodium arsenite, but not those induced by hydrogen peroxide, leading to cell death and revealing PB-microtubule attachment is required for hydrogen peroxide-induced SG anti-apoptotic functions. Furthermore, p50(Nesp1) was required for miRNA-mediated silencing and interacted with core miRISC silencers Ago2 and Rck/p54 in an RNA-dependent manner and with GW182 in a microtubule-dependent manner. These data identify p50(Nesp1) as a multi-functional PB component and microtubule scaffold necessary for RNA granule dynamics and provides evidence for PB and SG micro-heterogeneity.
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Affiliation(s)
- Dipen Rajgor
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Jason A Mellad
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Daniel Soong
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Jerome B Rattner
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Alberta, Canada
| | - Marvin J Fritzler
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Alberta, Canada
| | - Catherine M Shanahan
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
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18
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The Nesprin family member ANC-1 regulates synapse formation and axon termination by functioning in a pathway with RPM-1 and β-Catenin. PLoS Genet 2014; 10:e1004481. [PMID: 25010424 PMCID: PMC4091705 DOI: 10.1371/journal.pgen.1004481] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 05/16/2014] [Indexed: 01/08/2023] Open
Abstract
Mutations in Nesprin-1 and 2 (also called Syne-1 and 2) are associated with numerous diseases including autism, cerebellar ataxia, cancer, and Emery-Dreifuss muscular dystrophy. Nesprin-1 and 2 have conserved orthologs in flies and worms called MSP-300 and abnormal nuclear Anchorage 1 (ANC-1), respectively. The Nesprin protein family mediates nuclear and organelle anchorage and positioning. In the nervous system, the only known function of Nesprin-1 and 2 is in regulation of neurogenesis and neural migration. It remains unclear if Nesprin-1 and 2 regulate other functions in neurons. Using a proteomic approach in C. elegans, we have found that ANC-1 binds to the Regulator of Presynaptic Morphology 1 (RPM-1). RPM-1 is part of a conserved family of signaling molecules called Pam/Highwire/RPM-1 (PHR) proteins that are important regulators of neuronal development. We have found that ANC-1, like RPM-1, regulates axon termination and synapse formation. Our genetic analysis indicates that ANC-1 functions via the β-catenin BAR-1, and the ANC-1/BAR-1 pathway functions cell autonomously, downstream of RPM-1 to regulate neuronal development. Further, ANC-1 binding to the nucleus is required for its function in axon termination and synapse formation. We identify variable roles for four different Wnts (LIN-44, EGL-20, CWN-1 and CWN-2) that function through BAR-1 to regulate axon termination. Our study highlights an emerging, broad role for ANC-1 in neuronal development, and unveils a new and unexpected mechanism by which RPM-1 functions. The molecular mechanisms that underpin synapse formation and axon termination are central to forming a functional, fully connected nervous system. The PHR proteins are important regulators of neuronal development that function in axon outgrowth and termination, as well as synapse formation. Here we describe the discovery of a novel, conserved pathway that is positively regulated by the C. elegans PHR protein, RPM-1. This pathway is composed of RPM-1, ANC-1 (a Nesprin family protein), and BAR-1 (a canonical β-catenin). Nesprins, such as ANC-1, regulate nuclear anchorage and positioning in multinuclear cells. We now show that in neurons, ANC-1 regulates neuronal development by positively regulating BAR-1. Thus, Nesprins are multi-functional proteins that act through β-catenin to regulate neuronal development, and link the nucleus to the actin cytoskeleton in order to mediate nuclear anchorage and positioning in multi-nuclear cells.
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19
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Loebrich S. The role of F-actin in modulating Clathrin-mediated endocytosis: Lessons from neurons in health and neuropsychiatric disorder. Commun Integr Biol 2014; 7:e28740. [PMID: 25053985 PMCID: PMC4091099 DOI: 10.4161/cib.28740] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 12/22/2022] Open
Abstract
Clathrin-mediated endocytosis is one of several mechanisms for retrieving transmembrane proteins from the cell surface. This key mechanism is highly conserved in evolution and is found in any eukaryotic cell from yeast to mammals. Studies from several model organisms have revealed that filamentous actin (F-actin) plays multiple distinct roles in shaping Clathrin-mediated endocytosis. Yet, despite the identification of numerous molecules at the interface between endocytic machinery and the cytoskeleton, our mechanistic understanding of how F-actin regulates endocytosis remains limited. Key insights come from neurons where vesicular release and internalization are critical to pre- and postsynaptic function. Recent evidence from human genetics puts postsynaptic organization, glutamate receptor trafficking, and F-actin remodeling in the spotlight as candidate mechanisms underlying neuropsychiatric disorders. Here I review recent findings that connect the F-actin cytoskeleton mechanistically to Clathrin-mediated endocytosis in the central nervous system, and discuss their potential involvement in conferring risk for neuropsychiatric disorder.
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Affiliation(s)
- Sven Loebrich
- Picower Institute for Learning and Memory; Massachusetts Institute of Technology; Cambridge, MA USA
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20
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Xu W, Cohen-Woods S, Chen Q, Noor A, Knight J, Hosang G, Parikh SV, De Luca V, Tozzi F, Muglia P, Forte J, McQuillin A, Hu P, Gurling HMD, Kennedy JL, McGuffin P, Farmer A, Strauss J, Vincent JB. Genome-wide association study of bipolar disorder in Canadian and UK populations corroborates disease loci including SYNE1 and CSMD1. BMC MEDICAL GENETICS 2014; 15:2. [PMID: 24387768 PMCID: PMC3901032 DOI: 10.1186/1471-2350-15-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 12/20/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND Recently, genome-wide association studies (GWAS) for cases versus controls using single nucleotide polymorphism microarray data have shown promising findings for complex neuropsychiatric disorders, including bipolar disorder (BD). METHODS Here we describe a comprehensive genome-wide study of bipolar disorder (BD), cross-referencing analysis from a family-based study of 229 small families with association analysis from over 950 cases and 950 ethnicity-matched controls from the UK and Canada. Further, loci identified in these analyses were supported by pathways identified through pathway analysis on the samples. RESULTS Although no genome-wide significant markers were identified, the combined GWAS findings have pointed to several genes of interest that support GWAS findings for BD from other groups or consortia, such as at SYNE1 on 6q25, PPP2R2C on 4p16.1, ZNF659 on 3p24.3, CNTNAP5 (2q14.3), and CDH13 (16q23.3). This apparent corroboration across multiple sites gives much confidence to the likelihood of genetic involvement in BD at these loci. In particular, our two-stage strategy found association in both our combined case/control analysis and the family-based analysis on 1q21.2 (closest gene: sphingosine-1-phosphate receptor 1 gene, S1PR1) and on 1q24.1 near the gene TMCO1, and at CSMD1 on 8p23.2, supporting several previous GWAS reports for BD and for schizophrenia. Pathway analysis suggests association of pathways involved in calcium signalling, neuropathic pain signalling, CREB signalling in neurons, glutamate receptor signalling and axonal guidance signalling. CONCLUSIONS The findings presented here show support for a number of genes previously implicated genes in the etiology of BD, including CSMD1 and SYNE1, as well as evidence for previously unreported genes such as the brain-expressed genes ADCY2, NCALD, WDR60, SCN7A and SPAG16.
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Affiliation(s)
- Wei Xu
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Sarah Cohen-Woods
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Qian Chen
- Cancer Care Ontario, Toronto, Canada
| | - Abdul Noor
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Jo Knight
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Georgina Hosang
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Sagar V Parikh
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | | | - Federica Tozzi
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Pierandrea Muglia
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- Exploratory Medicine & Early Development, NeuroSearch, Copenhagen, Denmark
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Julia Forte
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Andrew McQuillin
- Molecular Psychiatry Laboratory, Mental Health Sciences Unit, Faculty of Brain Sciences, University College London, London, UK
| | - Pingzhao Hu
- The Centre for Applied Genomics, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Hugh MD Gurling
- Molecular Psychiatry Laboratory, Mental Health Sciences Unit, Faculty of Brain Sciences, University College London, London, UK
| | - James L Kennedy
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Peter McGuffin
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Anne Farmer
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - John Strauss
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - John B Vincent
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- The Institute of Medical Science, University of Toronto, Toronto, Canada
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21
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Razafsky D, Wirtz D, Hodzic D. Nuclear envelope in nuclear positioning and cell migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:471-90. [PMID: 24563361 PMCID: PMC4310828 DOI: 10.1007/978-1-4899-8032-8_21] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hauling and anchoring the nucleus within immobile or motile cells, tissues, and/or syncytia represents a major challenge. In the past 15 years, Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes) have emerged as evolutionary-conserved molecular devices that span the nuclear envelope and provide interacting interfaces for cytoskeletal networks and molecular motors to the nuclear envelope. Here, we review the molecular composition of LINC complexes and focus on how their genetic alteration in vivo has provided a wealth of information related to the relevance of nuclear positioning during tissue development and homeostasis with a special emphasis on the central nervous system. As it may be relevant for metastasis in a range of cancers, the involvement of LINC complexes in migration of nonneuronal cells via its interaction with the perinuclear actin cap will also be developed.
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Affiliation(s)
- David Razafsky
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
| | - Denis Wirtz
- The Johns Hopkins University, Department of Chemical and Biomolecular engineering, 3400 North Charles St., Baltimore, MD, 21218, USA
| | - Didier Hodzic
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
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22
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Alam S, Lovett DB, Dickinson RB, Roux KJ, Lele TP. Nuclear forces and cell mechanosensing. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:205-15. [PMID: 25081619 DOI: 10.1016/b978-0-12-394624-9.00008-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cells respond to mechanical signals, but the subcellular mechanisms are not well understood. The nucleus has recently emerged as an important mechanosensory organelle in the cell, as it is intimately connected to the cytoskeleton. Mechanical forces applied to cells that act on membrane-embedded receptors are transmitted through the cytoskeleton to the nuclear surface. Interfering with linkers of the nucleus to the cytoskeleton causes defects in cell mechanosensing and cell function. In this chapter, we discuss recent work in this area, highlighting the role that the nuclear linkages with the cytoskeleton play in cellular mechanotransduction.
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Affiliation(s)
- Samer Alam
- Department of Chemical Engineering, University of Florida, Gainesville, Florida, USA
| | - David B Lovett
- Department of Chemical Engineering, University of Florida, Gainesville, Florida, USA
| | - Richard B Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, Florida, USA
| | - Kyle J Roux
- Sanford Children's Health Research Center, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, Florida, USA
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23
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Regulation of glutamate receptor internalization by the spine cytoskeleton is mediated by its PKA-dependent association with CPG2. Proc Natl Acad Sci U S A 2013; 110:E4548-56. [PMID: 24191017 DOI: 10.1073/pnas.1318860110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A key neuronal mechanism for adjusting excitatory synaptic strength is clathrin-mediated endocytosis of postsynaptic glutamate receptors (GluRs). The actin cytoskeleton is critical for clathrin-mediated endocytosis, yet we lack a mechanistic understanding of its interaction with the endocytic process and how it may be regulated. Here we show that F-actin in dendritic spines physically binds the synaptic nuclear envelope 1 gene product candidate plasticity gene 2 (CPG2) in a PKA-dependent manner, and that this association is required for synaptic GluR internalization. Mutating two PKA sites on CPG2 disrupts its cytoskeletal association, attenuating GluR endocytosis and affecting the efficacy of synaptic transmission in vivo. These results identify CPG2 as an F-actin binding partner that functionally mediates interaction of the spine cytoskeleton with postsynaptic endocytosis. Further, the regulation of CPG2/F-actin association by PKA provides a gateway for cellular control of synaptic receptor internalization through second messenger signaling pathways. Recent identification of human synaptic nuclear envelope 1 as a risk locus for bipolar disorder suggests that CPG2 could play a role in synaptic dysfunction underlying neuropsychiatric disease.
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24
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Abstract
Nuclear envelope
spectrin-repeat
proteins (Nesprins), are a novel family of
nuclear and cytoskeletal proteins with rapidly expanding roles as intracellular scaffolds
and linkers. Originally described as proteins that localise to the nuclear envelope (NE)
and establish nuclear-cytoskeletal connections, nesprins have now been found to comprise a
diverse spectrum of tissue specific isoforms that localise to multiple sub-cellular
compartments. Here, we describe how nesprins are necessary in maintaining cellular
architecture by acting as essential scaffolds and linkers at both the NE and other
sub-cellular domains. More importantly, we speculate how nesprin mutations may disrupt
tissue specific nesprin scaffolds and explain the tissue specific nature of many
nesprin-associated diseases, including laminopathies.
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25
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Schwartz C, Hampton M, Andrews MT. Seasonal and regional differences in gene expression in the brain of a hibernating mammal. PLoS One 2013; 8:e58427. [PMID: 23526982 PMCID: PMC3603966 DOI: 10.1371/journal.pone.0058427] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/04/2013] [Indexed: 12/21/2022] Open
Abstract
Mammalian hibernation presents a unique opportunity to study naturally occurring neuroprotection. Hibernating ground squirrels undergo rapid and extreme physiological changes in body temperature, oxygen consumption, and heart rate without suffering neurological damage from ischemia and reperfusion injury. Different brain regions show markedly different activity during the torpor/arousal cycle: the cerebral cortex shows activity only during the periodic returns to normothermia, while the hypothalamus is active over the entire temperature range. Therefore, region-specific neuroprotective strategies must exist to permit this compartmentalized spectrum of activity. In this study, we use the Illumina HiSeq platform to compare the transcriptomes of these two brain regions at four collection points across the hibernation season: April Active, October Active, Torpor, and IBA. In the cerebral cortex, 1,085 genes were found to be differentially expressed across collection points, while 1,063 genes were differentially expressed in the hypothalamus. Comparison of these transcripts indicates that the cerebral cortex and hypothalamus implement very different strategies during hibernation, showing less than 20% of these differentially expressed genes in common. The cerebral cortex transcriptome shows evidence of remodeling and plasticity during hibernation, including transcripts for the presynaptic cytomatrix proteins bassoon and piccolo, and extracellular matrix components, including laminins and collagens. Conversely, the hypothalamic transcriptome displays upregulation of transcripts involved in damage response signaling and protein turnover during hibernation, including the DNA damage repair gene RAD50 and ubiquitin E3 ligases UBR1 and UBR5. Additionally, the hypothalamus transcriptome also provides evidence of potential mechanisms underlying the hibernation phenotype, including feeding and satiety signaling, seasonal timing mechanisms, and fuel utilization. This study provides insight into potential neuroprotective strategies and hibernation control mechanisms, and also specifically shows that the hibernator brain exhibits both seasonal and regional differences in mRNA expression.
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Affiliation(s)
- Christine Schwartz
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota, United States of America
| | - Marshall Hampton
- Department of Mathematics and Statistics, University of Minnesota Duluth, Duluth, Minnesota, United States of America
| | - Matthew T. Andrews
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota, United States of America
- * E-mail:
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26
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Yu T, Chahrour M, Coulter M, Jiralerspong S, Okamura-Ikeda K, Ataman B, Schmitz-Abe K, Harmin D, Adli M, Malik A, D’Gama A, Lim E, Sanders S, Mochida G, Partlow J, Sunu C, Felie J, Rodriguez J, Nasir R, Ware J, Joseph R, Hill R, Kwan B, Al-Saffar M, Mukaddes N, Hashmi A, Balkhy S, Gascon G, Hisama F, LeClair E, Poduri A, Oner O, Al-Saad S, Al-Awadi S, Bastaki L, Ben-Omran T, Teebi A, Al-Gazali L, Eapen V, Stevens C, Rappaport L, Gabriel S, Markianos K, State M, Greenberg M, Taniguchi H, Braverman N, Morrow E, Walsh C. Using whole-exome sequencing to identify inherited causes of autism. Neuron 2013; 77:259-73. [PMID: 23352163 PMCID: PMC3694430 DOI: 10.1016/j.neuron.2012.11.002] [Citation(s) in RCA: 334] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2012] [Indexed: 01/01/2023]
Abstract
Despite significant heritability of autism spectrum disorders (ASDs), their extreme genetic heterogeneity has proven challenging for gene discovery. Studies of primarily simplex families have implicated de novo copy number changes and point mutations, but are not optimally designed to identify inherited risk alleles. We apply whole-exome sequencing (WES) to ASD families enriched for inherited causes due to consanguinity and find familial ASD associated with biallelic mutations in disease genes (AMT, PEX7, SYNE1, VPS13B, PAH, and POMGNT1). At least some of these genes show biallelic mutations in nonconsanguineous families as well. These mutations are often only partially disabling or present atypically, with patients lacking diagnostic features of the Mendelian disorders with which these genes are classically associated. Our study shows the utility of WES for identifying specific genetic conditions not clinically suspected and the importance of partial loss of gene function in ASDs.
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Affiliation(s)
- T.W. Yu
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA, 02114
| | - M.H. Chahrour
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - M.E. Coulter
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - S. Jiralerspong
- Department of Human Genetics and Pediatrics, McGill University, Montreal Children’s Hospital Research Institute, Montreal, Quebec, Canada, H3H1P3
| | - K. Okamura-Ikeda
- Institute for Enzyme Research, The University of Tokushima, Tokushima, Japan
| | - B. Ataman
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - K. Schmitz-Abe
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - D.A. Harmin
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - M. Adli
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia, USA, 22908
| | - A.N. Malik
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - A.M. D’Gama
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - E.T. Lim
- Analytic and Translational Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, USA, 02114
| | - S.J. Sanders
- Department of Genetics, Center for Human Genetics and Genomics and Program on Neurogenetics, Yale University School of Medicine, New Haven, Connecticut, USA, 06510
| | - G.H. Mochida
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA, 02114
| | - J.N. Partlow
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - C.M. Sunu
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - J.M. Felie
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - J. Rodriguez
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - R.H. Nasir
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - J. Ware
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - R.M. Joseph
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA, 02118
| | - R.S. Hill
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - B.Y. Kwan
- Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada, N6A 5C1
| | - M. Al-Saffar
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Department of Paediatrics, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - N.M. Mukaddes
- Istanbul Faculty of Medicine, Department of Child Psychiatry, Istanbul University, Istanbul, Turkey
| | - A. Hashmi
- Armed Forces Hospital, King Abdulaziz Naval Base, Jubail, Kingdom of Saudi Arabia
| | - S. Balkhy
- Department of Neurosciences and Pediatrics, King Faisal Specialist Hospital and Research Center, Jeddah, Kingdom of Saudi Arabia
| | - G.G. Gascon
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA, 02114
- Istanbul Faculty of Medicine, Department of Child Psychiatry, Istanbul University, Istanbul, Turkey
- Clinical Neurosciences and Pediatrics, Brown University School of Medicine, Providence, Rhode Island, 02912
| | - F.M. Hisama
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, USA, 98195
| | - E. LeClair
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - A. Poduri
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts, USA,02115
| | - O. Oner
- Department of Child and Adolescent Psychiatry, Dr Sami Ulus Childrens’ Hospital, Telsizler, Ankara, Turkey
| | - S. Al-Saad
- Kuwait Center for Autism, Kuwait City, Kuwait
| | | | - L. Bastaki
- Kuwait Medical Genetics Center, Kuwait City, Kuwait
| | - T. Ben-Omran
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
- Departments of Pediatrics and Genetic Medicine, Weil-Cornell Medical College, New York and Doha, Qatar
| | - A. Teebi
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
- Departments of Pediatrics and Genetic Medicine, Weil-Cornell Medical College, New York and Doha, Qatar
| | - L. Al-Gazali
- Department of Paediatrics, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - V. Eapen
- Academic Unit of Child Psychiatry South West Sydney (AUCS), University of New South Wales, Sydney, New South Wales, Australia
| | - C.R. Stevens
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA, 02142
| | - L. Rappaport
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
| | - S.B. Gabriel
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA, 02142
| | - K. Markianos
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - M.W. State
- Department of Genetics, Center for Human Genetics and Genomics and Program on Neurogenetics, Yale University School of Medicine, New Haven, Connecticut, USA, 06510
| | - M.E. Greenberg
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - H. Taniguchi
- Institute for Enzyme Research, The University of Tokushima, Tokushima, Japan
| | - N.E. Braverman
- Department of Human Genetics and Pediatrics, McGill University, Montreal Children’s Hospital Research Institute, Montreal, Quebec, Canada, H3H1P3
| | - E.M. Morrow
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, 02912
- Department of Psychiatry and Human Behavior, Brown University, Providence, Rhode Island, 02912
| | - C.A. Walsh
- Division of Genetics, Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, USA, 02115
- The Autism Consortium, Boston, Massachusetts, USA, 02115
- Harvard Medical School, Boston, Massachusetts, USA, 02115
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27
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Lu W, Schneider M, Neumann S, Jaeger VM, Taranum S, Munck M, Cartwright S, Richardson C, Carthew J, Noh K, Goldberg M, Noegel AA, Karakesisoglou I. Nesprin interchain associations control nuclear size. Cell Mol Life Sci 2012; 69:3493-509. [PMID: 22653047 PMCID: PMC11114684 DOI: 10.1007/s00018-012-1034-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 04/26/2012] [Accepted: 05/14/2012] [Indexed: 12/12/2022]
Abstract
Nesprins-1/-2/-3/-4 are nuclear envelope proteins, which connect nuclei to the cytoskeleton. The largest nesprin-1/-2 isoforms (termed giant) tether F-actin through their N-terminal actin binding domain (ABD). Nesprin-3, however, lacks an ABD and associates instead to plectin, which binds intermediate filaments. Nesprins are integrated into the outer nuclear membrane via their C-terminal KASH-domain. Here, we show that nesprin-1/-2 ABDs physically and functionally interact with nesprin-3. Thus, both ends of nesprin-1/-2 giant are integrated at the nuclear surface: via the C-terminal KASH-domain and the N-terminal ABD-nesprin-3 association. Interestingly, nesprin-2 ABD or KASH-domain overexpression leads to increased nuclear areas. Conversely, nesprin-2 mini (contains the ABD and KASH-domain but lacks the massive nesprin-2 giant rod segment) expression yields smaller nuclei. Nuclear shrinkage is further enhanced upon nesprin-3 co-expression or microfilament depolymerization. Our findings suggest that multivariate intermolecular nesprin interactions with the cytoskeleton form a lattice-like filamentous network covering the outer nuclear membrane, which determines nuclear size.
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Affiliation(s)
- Wenshu Lu
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Maria Schneider
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Sascha Neumann
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Verena-Maren Jaeger
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Surayya Taranum
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Martina Munck
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
| | - Sarah Cartwright
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - Christine Richardson
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - James Carthew
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - Kowoon Noh
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - Martin Goldberg
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - Angelika A. Noegel
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany
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28
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Leussis MP, Madison JM, Petryshen TL. Ankyrin 3: genetic association with bipolar disorder and relevance to disease pathophysiology. BIOLOGY OF MOOD & ANXIETY DISORDERS 2012; 2:18. [PMID: 23025490 PMCID: PMC3492013 DOI: 10.1186/2045-5380-2-18] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/20/2012] [Indexed: 11/26/2022]
Abstract
Bipolar disorder (BD) is a multi-factorial disorder caused by genetic and environmental influences. It has a large genetic component, with heritability estimated between 59-93%. Recent genome-wide association studies (GWAS) using large BD patient populations have identified a number of genes with strong statistical evidence for association with susceptibility for BD. Among the most significant and replicated genes is ankyrin 3 (ANK3), a large gene that encodes multiple isoforms of the ankyrin G protein. This article reviews the current evidence for genetic association of ANK3 with BD, followed by a comprehensive overview of the known biology of the ankyrin G protein, focusing on its neural functions and their potential relevance to BD. Ankyrin G is a scaffold protein that is known to have many essential functions in the brain, although the mechanism by which it contributes to BD is unknown. These functions include organizational roles for subcellular domains in neurons including the axon initial segment and nodes of Ranvier, through which ankyrin G orchestrates the localization of key ion channels and GABAergic presynaptic terminals, as well as creating a diffusion barrier that limits transport into the axon and helps define axo-dendritic polarity. Ankyrin G is postulated to have similar structural and organizational roles at synaptic terminals. Finally, ankyrin G is implicated in both neurogenesis and neuroprotection. ANK3 and other BD risk genes participate in some of the same biological pathways and neural processes that highlight several mechanisms by which they may contribute to BD pathophysiology. Biological investigation in cellular and animal model systems will be critical for elucidating the mechanism through which ANK3 confers risk of BD. This knowledge is expected to lead to a better understanding of the brain abnormalities contributing to BD symptoms, and to potentially identify new targets for treatment and intervention approaches.
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Affiliation(s)
- Melanie P Leussis
- Psychiatric and Neurodevelopmental Genetics Unit, Department of Psychiatry and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA.
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29
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Rajgor D, Mellad JA, Autore F, Zhang Q, Shanahan CM. Multiple novel nesprin-1 and nesprin-2 variants act as versatile tissue-specific intracellular scaffolds. PLoS One 2012; 7:e40098. [PMID: 22768332 PMCID: PMC3388047 DOI: 10.1371/journal.pone.0040098] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/31/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Nesprins (Nuclear envelope spectrin-repeat proteins) are a novel family of giant spectrin-repeat containing proteins. The nesprin-1 and nesprin-2 genes consist of 146 and 116 exons which encode proteins of ∼1mDa and ∼800 kDa is size respectively when all the exons are utilised in translation. However emerging data suggests that the nesprins have multiple alternative start and termination sites throughout their genes allowing the generation of smaller isoforms. RESULTS In this study we set out to identify novel alternatively transcribed nesprin variants by screening the EST database and by using RACE analysis to identify cDNA ends. These two methods provided potential hits for alternative start and termination sites that were validated by PCR and DNA sequencing. We show that these alternative sites are not only expressed in a tissue specific manner but by combining different sites together it is possible to create a wide array of nesprin variants. By cloning and expressing small novel nesprin variants into human fibroblasts and U2OS cells we show localization to actin stress-fibres, focal adhesions, microtubules, the nucleolus, nuclear matrix and the nuclear envelope (NE). Furthermore we show that the sub-cellular localization of individual nesprin variants can vary depending on the cell type, suggesting any single nesprin variant may have different functions in different cell types. CONCLUSIONS These studies suggest nesprins act as highly versatile tissue specific intracellular protein scaffolds and identify potential novel functions for nesprins beyond cytoplasmic-nuclear coupling. These alternate functions may also account for the diverse range of disease phenotypes observed when these genes are mutated.
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Affiliation(s)
- Dipen Rajgor
- Cardiovascular Division, James Black Centre, King’s College London, London, United Kingdom
| | - Jason A. Mellad
- Cardiovascular Division, James Black Centre, King’s College London, London, United Kingdom
| | - Flavia Autore
- The Randall Division of Cell and Molecular Biophysics, New Hunt’s House, King’s College London, London, United Kingdom
| | - Qiuping Zhang
- Cardiovascular Division, James Black Centre, King’s College London, London, United Kingdom
| | - Catherine M. Shanahan
- Cardiovascular Division, James Black Centre, King’s College London, London, United Kingdom
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30
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Smith ER, Zhang XY, Capo-Chichi CD, Chen X, Xu XX. Increased expression of Syne1/nesprin-1 facilitates nuclear envelope structure changes in embryonic stem cell differentiation. Dev Dyn 2011; 240:2245-55. [PMID: 21932307 DOI: 10.1002/dvdy.22717] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2011] [Indexed: 01/16/2023] Open
Abstract
We found by electron microscopy that the inter-membrane space of embryonic stem cells is irregular and generally wider than in differentiated cells. Among a panel of nuclear envelope structural proteins examined, the expression of Syne1/nesprin-1 was found to be greatly induced upon differentiation. Down-regulation of Syne1 by siRNA in differentiated embryonic stem cells caused the nuclear envelope to adopt a configuration resembling that found in undifferentiated embryonic stem cells. Suppression of Syne1 expression did not produce a detectable impact on the retinoic acid-induced differentiation of embryonic stem cells; however, forced expression of Syne1 enhanced the tendency of the cells to lose pluripotency. Thus, we found that low expression of Syne1 splicing isoforms accounts for the wider and irregular nuclear envelope inter-membrane space in embryonic stem cells. We conclude that the nuclear envelope structural change accompanying differentiation likely participates in promoting the differential chromatin organization of the differentiated cells.
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Affiliation(s)
- Elizabeth R Smith
- Sylvester Comprehensive Cancer Center, Department of Medicine, and Department of Obstetrics and Gynecology, University of Miami School of Medicine, Miami, Florida, USA
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31
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The AAA+ ATPase Thorase regulates AMPA receptor-dependent synaptic plasticity and behavior. Cell 2011; 145:284-99. [PMID: 21496646 DOI: 10.1016/j.cell.2011.03.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Revised: 12/30/2010] [Accepted: 03/07/2011] [Indexed: 01/22/2023]
Abstract
The synaptic insertion or removal of AMPA receptors (AMPAR) plays critical roles in the regulation of synaptic activity reflected in the expression of long-term potentiation (LTP) and long-term depression (LTD). The cellular events underlying this important process in learning and memory are still being revealed. Here we describe and characterize the AAA+ ATPase Thorase, which regulates the expression of surface AMPAR. In an ATPase-dependent manner Thorase mediates the internalization of AMPAR by disassembling the AMPAR-GRIP1 complex. Following genetic deletion of Thorase, the internalization of AMPAR is substantially reduced, leading to increased amplitudes of miniature excitatory postsynaptic currents, enhancement of LTP, and elimination of LTD. These molecular events are expressed as deficits in learning and memory in Thorase null mice. This study identifies an AAA+ ATPase that plays a critical role in regulating the surface expression of AMPAR and thereby regulates synaptic plasticity and learning and memory.
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32
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Leslie JH, Nedivi E. Activity-regulated genes as mediators of neural circuit plasticity. Prog Neurobiol 2011; 94:223-37. [PMID: 21601615 DOI: 10.1016/j.pneurobio.2011.05.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Modifications of neuronal circuits allow the brain to adapt and change with experience. This plasticity manifests during development and throughout life, and can be remarkably long lasting. Evidence has linked activity-regulated gene expression to the long-term structural and electrophysiological adaptations that take place during developmental critical periods, learning and memory, and alterations to sensory map representations in the adult. In all these cases, the cellular response to neuronal activity integrates multiple tightly coordinated mechanisms to precisely orchestrate long-lasting, functional and structural changes in brain circuits. Experience-dependent plasticity is triggered when neuronal excitation activates cellular signaling pathways from the synapse to the nucleus that initiate new programs of gene expression. The protein products of activity-regulated genes then work via a diverse array of cellular mechanisms to modify neuronal functional properties. Synaptic strengthening or weakening can reweight existing circuit connections, while structural changes including synapse addition and elimination create new connections. Posttranscriptional regulatory mechanisms, often also dependent on activity, further modulate activity-regulated gene transcript and protein function. Thus, activity-regulated genes implement varied forms of structural and functional plasticity to fine-tune brain circuit wiring.
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Affiliation(s)
- Jennifer H Leslie
- Department of Biology, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
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33
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Starr DA, Fridolfsson HN. Interactions between nuclei and the cytoskeleton are mediated by SUN-KASH nuclear-envelope bridges. Annu Rev Cell Dev Biol 2010; 26:421-44. [PMID: 20507227 DOI: 10.1146/annurev-cellbio-100109-104037] [Citation(s) in RCA: 438] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The nuclear envelope links the cytoskeleton to structural components of the nucleus. It functions to coordinate nuclear migration and anchorage, organize chromatin, and aid meiotic chromosome pairing. Forces generated by the cytoskeleton are transferred across the nuclear envelope to the nuclear lamina through a nuclear-envelope bridge consisting of SUN (Sad1 and UNC-84) and KASH (Klarsicht, ANC-1 and Syne/Nesprin homology) proteins. Some KASH-SUN combinations connect microtubules, centrosomes, actin filaments, or intermediate filaments to the surface of the nucleus. Other combinations are used in cell cycle control, nuclear import, or apoptosis. Interactions between the cytoskeleton and the nucleus also affect global cytoskeleton organization. SUN and KASH proteins were identified through genetic screens for mispositioned nuclei in model organisms. Knockouts of SUN or KASH proteins disrupt neurological and muscular development in mice. Defects in SUN and KASH proteins have been linked to human diseases including muscular dystrophy, ataxia, progeria, lissencephaly, and cancer.
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Affiliation(s)
- Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
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34
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Peng F, Yao H, Bai X, Zhu X, Reiner BC, Beazely M, Funa K, Xiong H, Buch S. Platelet-derived growth factor-mediated induction of the synaptic plasticity gene Arc/Arg3.1. J Biol Chem 2010; 285:21615-24. [PMID: 20452974 DOI: 10.1074/jbc.m110.107003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet-derived growth factor (PDGF) is a pleiotropic protein with critical roles in both developmental as well as pathogenic processes. In the central nervous system specifically, PDGF is critical for neuronal proliferation and differentiation and has also been implicated as a neuroprotective agent. Whether PDGF also plays a role in synaptic plasticity, however, remains poorly understood. In the present study we demonstrated that in the rat hippocampal neurons PDGF regulated the expression of Arc/Arg3.1 gene that has been implicated in both synapse plasticity and long term potentiation. Relevance of these findings was further confirmed in vivo by injecting mice with intracerebral inoculations of PDGF, which resulted in a rapid induction of Arc in the hippocampus of the injected mice. PDGF induced long term potentiation in rat hippocampal slices, which was abolished by PDGF receptor-tyrosine kinase inhibitor STI-571. We also present evidence that PDGF-mediated induction of Arc/Arg3.1 involved activation of the MAPK/ERK (MEK) pathway. Additionally, induction of Arc/Arg3.1 also involved the upstream release of intracellular calcium stores, an effect that could be blocked by thapsigargin but not by EGTA. Pharmacological approach using inhibitors specific for either MAPK/ERK phosphorylation or calcium release demonstrated that the two pathways converged downstream at a common point involving activation of the immediate early gene Egr-1. Chromatin immunoprecipitation assays demonstrated the binding of Egr-1, but not Egr-3, to the Arc promoter. These findings for the first time, thus, suggest an additional role of PDGF, that of induction of Arc.
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Affiliation(s)
- Fuwang Peng
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198-5880, USA
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Zhao WQ, Santini F, Breese R, Ross D, Zhang XD, Stone DJ, Ferrer M, Townsend M, Wolfe AL, Seager MA, Kinney GG, Shughrue PJ, Ray WJ. Inhibition of calcineurin-mediated endocytosis and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors prevents amyloid beta oligomer-induced synaptic disruption. J Biol Chem 2009; 285:7619-32. [PMID: 20032460 DOI: 10.1074/jbc.m109.057182] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Synaptic degeneration, including impairment of synaptic plasticity and loss of synapses, is an important feature of Alzheimer disease pathogenesis. Increasing evidence suggests that these degenerative synaptic changes are associated with an accumulation of soluble oligomeric assemblies of amyloid beta (Abeta) known as ADDLs. In primary hippocampal cultures ADDLs bind to a subpopulation of neurons. However the molecular basis of this cell type-selective interaction is not understood. Here, using siRNA screening technology, we identified alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits and calcineurin as candidate genes potentially involved in ADDL-neuron interactions. Immunocolocalization experiments confirmed that ADDL binding occurs in dendritic spines that express surface AMPA receptors, particularly the calcium-impermeable type II AMPA receptor subunit (GluR2). Pharmacological removal of the surface AMPA receptors or inhibition of AMPA receptors with antagonists reduces ADDL binding. Furthermore, using co-immunoprecipitation and photoreactive amino acid cross-linking, we found that ADDLs interact preferentially with GluR2-containing complexes. We demonstrate that calcineurin mediates an endocytotic process that is responsible for the rapid internalization of bound ADDLs along with surface AMPA receptor subunits, which then both colocalize with cpg2, a molecule localized specifically at the postsynaptic endocytic zone of excitatory synapses that plays an important role in activity-dependent glutamate receptor endocytosis. Both AMPA receptor and calcineurin inhibitors prevent oligomer-induced surface AMPAR and spine loss. These results support a model of disease pathogenesis in which Abeta oligomers interact selectively with neurotransmission pathways at excitatory synapses, resulting in synaptic loss via facilitated endocytosis. Validation of this model in human disease would identify therapeutic targets for Alzheimer disease.
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Affiliation(s)
- Wei-Qin Zhao
- Department of Neurology, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
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Loebrich S, Nedivi E. The function of activity-regulated genes in the nervous system. Physiol Rev 2009; 89:1079-103. [PMID: 19789377 DOI: 10.1152/physrev.00013.2009] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mammalian brain is plastic in the sense that it shows a remarkable capacity for change throughout life. The contribution of neuronal activity to brain plasticity was first recognized in relation to critical periods of development, when manipulating the sensory environment was found to profoundly affect neuronal morphology and receptive field properties. Since then, a growing body of evidence has established that brain plasticity extends beyond development and is an inherent feature of adult brain function, spanning multiple domains, from learning and memory to adaptability of primary sensory maps. Here we discuss evolution of the current view that plasticity of the adult brain derives from dynamic tuning of transcriptional control mechanisms at the neuronal level, in response to external and internal stimuli. We then review the identification of "plasticity genes" regulated by changes in the levels of electrical activity, and how elucidating their cellular functions has revealed the intimate role transcriptional regulation plays in fundamental aspects of synaptic transmission and circuit plasticity that occur in the brain on an every day basis.
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Affiliation(s)
- Sven Loebrich
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Endocytic trafficking and recycling maintain a pool of mobile surface AMPA receptors required for synaptic potentiation. Neuron 2009; 63:92-105. [PMID: 19607795 DOI: 10.1016/j.neuron.2009.05.025] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 03/02/2009] [Accepted: 05/15/2009] [Indexed: 11/21/2022]
Abstract
At excitatory glutamatergic synapses, postsynaptic endocytic zones (EZs), which are adjacent to the postsynaptic density (PSD), mediate clathrin-dependent endocytosis of surface AMPA receptors (AMPAR) as a first step to receptor recycling or degradation. However, it remains unknown whether receptor recycling influences AMPAR lateral diffusion and whether EZs are important for the expression of synaptic potentiation. Here, we demonstrate that the presence of both EZs and AMPAR recycling maintain a large pool of mobile AMPARs at synapses. In addition, we find that synaptic potentiation is accompanied by an accumulation and immobilization of AMPARs at synapses resulting from both their exocytosis and stabilization at the PSD. Displacement of EZs from the postsynaptic region impairs the expression of synaptic potentiation by blocking AMPAR recycling. Thus, receptor recycling is crucial for maintaining a mobile population of surface AMPARs that can be delivered to synapses for increases in synaptic strength.
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Borgonovo J, Seltzer A, Sosa MA. Acute intrastriatal administration of quinolinic acid affects the expression of the coat protein AP-2 and its interaction with membranes. J Neural Transm (Vienna) 2009; 116:1201-8. [PMID: 19597933 DOI: 10.1007/s00702-009-0262-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Accepted: 06/27/2009] [Indexed: 11/26/2022]
Abstract
Clathrin-coated vesicle endocytosis is thought to be crucial for the maintenance of synaptic transmission and for the cell plasticity at the nervous system. In this study, we demonstrated that acute intrastriatal administration of quinolinic acid (QUIN), an agonist of the N-methyl-D: -aspartate receptor, induces a decrease of the coat protein AP-2 expression and affects their interaction with membranes. By western blot analysis we observed that at 24 h after QUIN intrastriatal injection, alpha1 subunit of AP-2 and alpha2, at lesser extent, were reduced in the striatal membranes. The decrease of both subunits expression was extended to 48 h after treatment, although the soluble proteins were mostly affected. Other areas of the brain were not affected by the treatment, except the cerebellum, where a significant increase of soluble AP-2 (both subunits) was observed at 48 h after injection. Another coat protein, as the phosphoprotein AP-180, was not affected by the injection of QUIN. We also confirmed that QUIN injection causes increasing loss of striatal neurons after the administration of the toxin. We concluded that QUIN may affect the endocytotic machinery of the striatum, by inducing changes in the AP-2 behaviour. Consequently, the internalization of NMDAR and/or AMPAR may be affected, by QUIN, contributing to the excitotoxic effect of the drug.
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Affiliation(s)
- Janina Borgonovo
- Laboratorio de Biología y Fisiología Celular Dr. Francisco Bertini, Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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Abstract
Positioning the nucleus is essential for the formation of polarized cells, pronuclear migration, cell division, cell migration and the organization of specialized syncytia such as mammalian skeletal muscles. Proteins that are required for nuclear positioning also function during chromosome movement and pairing in meiosis. Defects in these processes lead to human diseases including laminopathies. To properly position the nucleus or move chromosomes within the nucleus, the cell must specify the outer surface of the nucleus and transfer forces across both membranes of the nuclear envelope. KASH proteins are specifically recruited to the outer nuclear membrane by SUN proteins, which reside in the inner nuclear membrane. KASH and SUN proteins physically interact in the perinuclear space, forming a bridge across the two membranes of the nuclear envelope. The divergent N-terminal domains of KASH proteins extend from the surface of the nucleus into the cytoplasm and interact with the cytoskeleton, whereas the N-termini of SUN proteins extend into the nucleoplasm to interact with the lamina or chromatin. The bridge of SUN and KASH across the nuclear envelope functions to transfer forces that are generated in the cytoplasm into the nucleoplasm during nuclear migration, nuclear anchorage, centrosome attachment, intermediate-filament association and telomere clustering.
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Affiliation(s)
- Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
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Davidson HT, Xiao J, Dai R, Bergson C. Calcyon is necessary for activity-dependent AMPA receptor internalization and LTD in CA1 neurons of hippocampus. Eur J Neurosci 2009; 29:42-54. [PMID: 19120439 DOI: 10.1111/j.1460-9568.2008.06563.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Calcyon is a single transmembrane endocytic protein that regulates clathrin assembly and clathrin-mediated endocytosis in the brain. Ultrastructural studies indicate that calcyon localizes to spines, but whether it regulates glutamate neurotransmission is not known. Here, we show that deletion of the calcyon gene in mice inhibits agonist-stimulated endocytosis of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), without altering basal surface levels of the GluR1 or GluR2 subunits. Whole-cell patch-clamp studies of hippocampal neurons in culture and CA1 synapses in slices revealed that knockout (KO) of calcyon abolishes long-term synaptic depression (LTD), whereas mini-analysis in slices indicated basal transmission in the hippocampus is unaffected by the deletion. Further, transfection of green fluorescent protein-tagged calcyon rescued the ability of KO cultures to undergo LTD. In contrast, intracellular dialysis of a fusion protein containing the clathrin light-chain-binding domain of calcyon blocked the induction of LTD in wild-type hippocampal slices. Taken together, the present studies involving biochemical, immunological and electrophysiological analyses raise the possibility that calcyon plays a specialized role in regulating activity-dependent removal of synaptic AMPARs.
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Burke B, Stewart CL. The laminopathies: the functional architecture of the nucleus and its contribution to disease. Annu Rev Genomics Hum Genet 2008; 7:369-405. [PMID: 16824021 DOI: 10.1146/annurev.genom.7.080505.115732] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most inherited diseases are associated with mutations in a specific gene. Often, mutations in two or more different genes result in diseases with a similar phenotype. Rarely do different mutations in the same gene result in a multitude of seemingly different and unrelated diseases. Mutations in the Lamin A gene (LMNA), which encodes largely ubiquitously expressed nuclear proteins (A-type lamins), are associated with at least eight different diseases, collectively called the laminopathies. Studies examining how different tissue-specific diseases arise from unique LMNA mutations are providing unanticipated insights into the structural organization of the nucleus, and how disruption of this organization relates to novel mechanisms of disease.
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Affiliation(s)
- Brian Burke
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610
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Sornarajah L, Vasuta OC, Zhang L, Sutton C, Li B, El-Husseini A, Raymond LA. NMDA receptor desensitization regulated by direct binding to PDZ1-2 domains of PSD-95. J Neurophysiol 2008; 99:3052-62. [PMID: 18400955 DOI: 10.1152/jn.90301.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of N-methyl-d-aspartate receptor (NMDAR) activity by desensitization is important in physiological and pathological states; NMDAR desensitization contributes in shaping synaptic responses and may be protective by limiting calcium influx during sustained glutamate insults. We previously reported that glycine-independent desensitization decreases during hippocampal neuronal development, correlating with NMDAR synaptic localization and association with postsynaptic density 95 (PSD-95). PSD-95/Discs large/zona occludens (PDZ)-1,2 domains of PSD-95 bind to the C-terminus of NMDAR NR2 subunits. The role of PSD-95 in anchoring signaling proteins near NMDARs is well documented. To determine if PSD-95-induced changes in NMDAR desensitization occur because of direct binding to NR2 or due to recruitment of regulatory proteins, we tested the effects of various PSD-95 constructs on NMDAR currents in human embryonic kidney 293 (HEK293) cells and neurons. In HEK cells, wild-type PSD-95 significantly reduced wild-type NMDAR desensitization without altering currents of NMDARs containing NR2A-S1462A, a mutation that abolishes PSD-95 binding. The PSD-95 N-terminus truncated after the PDZ1-2 domains was sufficient for this effect in neurons with low endogenous PSD-95 levels; in NMDAR-expressing HEK cells, the effect persisted when PSD-95 multimerization was eliminated. Moreover other PSD-95 family members with highly homologous PDZ1-2 domains significantly reduced NMDAR desensitization. In mature neurons, disruption of PSD-95/NMDAR interaction through protein kinase C (PKC) activation increased desensitization to levels found in immature neurons, and this effect was not due to PKC direct regulation of NMDAR activity. We conclude that direct binding of PSD-95 increases stability of NMDAR responses to agonist exposure in neuronal and nonneuronal cells.
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Affiliation(s)
- Lavan Sornarajah
- Graduate Program in Neuroscience, University of British Columbia, 4N3-2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
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Abstract
The cellular processes that govern neuronal function are highly complex, with many basic cell biological pathways uniquely adapted to perform the elaborate information processing achieved by the brain. This is particularly evident in the trafficking and regulation of membrane proteins to and from synapses, which can be a long distance away from the cell body and number in the thousands. The regulation of neurotransmitter receptors, such as the AMPA-type glutamate receptors (AMPARs), the major excitatory neurotransmitter receptors in the brain, is a crucial mechanism for the modulation of synaptic transmission. The levels of AMPARs at synapses are very dynamic, and it is these plastic changes in synaptic function that are thought to underlie information storage in the brain. Thus, understanding the cellular machinery that controls AMPAR trafficking will be critical for understanding the cellular basis of behavior as well as many neurological diseases. Here we describe the life cycle of AMPARs, from their biogenesis, through their journey to the synapse, and ultimately through their demise, and discuss how the modulation of this process is essential for brain function.
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Affiliation(s)
- Jason D Shepherd
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Lu J, Helton TD, Blanpied TA, Rácz B, Newpher TM, Weinberg RJ, Ehlers MD. Postsynaptic positioning of endocytic zones and AMPA receptor cycling by physical coupling of dynamin-3 to Homer. Neuron 2007; 55:874-89. [PMID: 17880892 PMCID: PMC2597538 DOI: 10.1016/j.neuron.2007.06.041] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 06/08/2007] [Accepted: 07/31/2007] [Indexed: 02/07/2023]
Abstract
Endocytosis of AMPA receptors and other postsynaptic cargo occurs at endocytic zones (EZs), stably positioned sites of clathrin adjacent to the postsynaptic density (PSD). The tight localization of postsynaptic endocytosis is thought to control spine composition and regulate synaptic transmission. However, the mechanisms that situate the EZ near the PSD and the role of spine endocytosis in synaptic transmission are unknown. Here, we report that a physical link between dynamin-3 and the postsynaptic adaptor Homer positions the EZ near the PSD. Disruption of dynamin-3 or its interaction with Homer uncouples the PSD from the EZ, resulting in synapses lacking postsynaptic clathrin. Loss of the EZ leads to a loss of synaptic AMPA receptors and reduced excitatory synaptic transmission that corresponds with impaired synaptic recycling. Thus, a physical link between the PSD and the EZ ensures localized endocytosis and recycling by recapturing and maintaining a proximate pool of cycling AMPA receptors.
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Affiliation(s)
- Jiuyi Lu
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Thomas D. Helton
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Thomas A. Blanpied
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Bence Rácz
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Thomas M. Newpher
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Richard J. Weinberg
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
- Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Michael D. Ehlers
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Corresponding Author: Michael D. Ehlers, M.D., Ph.D., Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Box 3209, Durham, NC 27710, USA, Tel: (919)684-1828, FAX (919)668-0631, e-mail:
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Dosemeci A, Makusky AJ, Jankowska-Stephens E, Yang X, Slotta DJ, Markey SP. Composition of the synaptic PSD-95 complex. Mol Cell Proteomics 2007; 6:1749-60. [PMID: 17623647 PMCID: PMC2096750 DOI: 10.1074/mcp.m700040-mcp200] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein interaction domains, forms the backbone of an extensive postsynaptic protein complex that organizes receptors and signal transduction molecules at the synaptic contact zone. Large, detergent-insoluble PSD-95-based postsynaptic complexes can be affinity-purified from conventional PSD fractions using magnetic beads coated with a PSD-95 antibody. In the present study purified PSD-95 complexes were analyzed by LC/MS/MS. A semiquantitative measure of the relative abundances of proteins in the purified PSD-95 complexes and the parent PSD fraction was estimated based on the cumulative ion current intensities of corresponding peptides. The affinity-purified preparation was largely depleted of presynaptic proteins, spectrin, intermediate filaments, and other contaminants prominent in the parent PSD fraction. We identified 525 of the proteins previously reported in parent PSD fractions, but only 288 of these were detected after affinity purification. We discuss 26 proteins that are major components in the PSD-95 complex based upon abundance ranking and affinity co-purification with PSD-95. This subset represents a minimal list of constituent proteins of the PSD-95 complex and includes, in addition to the specialized scaffolds and N-methyl-d-aspartate (NMDA) receptors, an abundance of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, small G-protein regulators, cell adhesion molecules, and hypothetical proteins. The identification of two Arf regulators, BRAG1 and BRAG2b, as co-purifying components of the complex implies pivotal functions in spine plasticity such as the reorganization of the actin cytoskeleton and insertion and retrieval of proteins to and from the plasma membrane. Another co-purifying protein (Q8BZM2) with two sterile alpha motif domains may represent a novel structural core element of the PSD.
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Affiliation(s)
- Ayse Dosemeci
- From the Laboratory of Neurobiology, NINDS, National Institutes of Health, Bethesda, Maryland 20892
| | - Anthony J. Makusky
- Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, Maryland 20892
| | - Ewa Jankowska-Stephens
- Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, Maryland 20892
| | - Xiaoyu Yang
- Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, Maryland 20892
| | - Douglas J. Slotta
- Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, Maryland 20892
| | - Sanford P. Markey
- Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, Maryland 20892
- To whom correspondence should be addressed. Tel.: 301−496−4022; Fax: 301−451−5780; E-mail: .
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Reuveni E, Ramensky VE, Gross C. Mouse SNP Miner: an annotated database of mouse functional single nucleotide polymorphisms. BMC Genomics 2007; 8:24. [PMID: 17239255 PMCID: PMC1797019 DOI: 10.1186/1471-2164-8-24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 01/21/2007] [Indexed: 12/05/2022] Open
Abstract
Background The mapping of quantitative trait loci in rat and mouse has been extremely successful in identifying chromosomal regions associated with human disease-related phenotypes. However, identifying the specific phenotype-causing DNA sequence variations within a quantitative trait locus has been much more difficult. The recent availability of genomic sequence from several mouse inbred strains (including C57BL/6J, 129X1/SvJ, 129S1/SvImJ, A/J, and DBA/2J) has made it possible to catalog DNA sequence differences within a quantitative trait locus derived from crosses between these strains. However, even for well-defined quantitative trait loci (<10 Mb) the identification of candidate functional DNA sequence changes remains challenging due to the high density of sequence variation between strains. Description To help identify functional DNA sequence variations within quantitative trait loci we have used the Ensembl annotated genome sequence to compile a database of mouse single nucleotide polymorphisms (SNPs) that are predicted to cause missense, nonsense, frameshift, or splice site mutations (available at ). For missense mutations we have used the PolyPhen and PANTHER algorithms to predict whether amino acid changes are likely to disrupt protein function. Conclusion We have developed a database of mouse SNPs predicted to cause missense, nonsense, frameshift, and splice-site mutations. Our analysis revealed that 20% and 14% of missense SNPs are likely to be deleterious according to PolyPhen and PANTHER, respectively, and 6% are considered deleterious by both algorithms. The database also provides gene expression and functional annotations from the Symatlas, Gene Ontology, and OMIM databases to further assess candidate phenotype-causing mutations. To demonstrate its utility, we show that Mouse SNP Miner successfully finds a previously identified candidate SNP in the taste receptor, Tas1r3, that underlies sucrose preference in the C57BL/6J strain. We also use Mouse SNP Miner to derive a list of candidate phenotype-causing mutations within a previously uncharacterized QTL for response to morphine in the 129/Sv strain.
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Affiliation(s)
- Eli Reuveni
- Mouse Biology Unit, EMBL, Via Ramarini 32, 00016 Monterotondo, Italy
| | - Vasily E Ramensky
- Engelhardt Institute of Molecular Biology, Vavilova 32, 119991 Moscow, Russia
| | - Cornelius Gross
- Mouse Biology Unit, EMBL, Via Ramarini 32, 00016 Monterotondo, Italy
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Chowdhury S, Shepherd JD, Okuno H, Lyford G, Petralia RS, Plath N, Kuhl D, Huganir RL, Worley PF. Arc/Arg3.1 interacts with the endocytic machinery to regulate AMPA receptor trafficking. Neuron 2007; 52:445-59. [PMID: 17088211 PMCID: PMC1784006 DOI: 10.1016/j.neuron.2006.08.033] [Citation(s) in RCA: 608] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 04/13/2006] [Accepted: 08/18/2006] [Indexed: 11/15/2022]
Abstract
Arc/Arg3.1 is an immediate-early gene whose mRNA is rapidly transcribed and targeted to dendrites of neurons as they engage in information processing and storage. Moreover, Arc/Arg3.1 is known to be required for durable forms of synaptic plasticity and learning. Despite these intriguing links to plasticity, Arc/Arg3.1's molecular function remains enigmatic. Here, we demonstrate that Arc/Arg3.1 protein interacts with dynamin and specific isoforms of endophilin to enhance receptor endocytosis. Arc/Arg3.1 selectively modulates trafficking of AMPA-type glutamate receptors (AMPARs) in neurons by accelerating endocytosis and reducing surface expression. The Arc/Arg3.1-endocytosis pathway appears to regulate basal AMPAR levels since Arc/Arg3.1 KO neurons exhibit markedly reduced endocytosis and increased steady-state surface levels. These findings reveal a novel molecular pathway that is regulated by Arc/Arg3.1 and likely contributes to late-phase synaptic plasticity and memory consolidation.
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Affiliation(s)
- Shoaib Chowdhury
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jason D. Shepherd
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular and Molecular Medicine Graduate Program, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiroyuki Okuno
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gregory Lyford
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ronald S. Petralia
- Laboratory of Neurochemistry, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892 USA
| | - Niels Plath
- Molecular Neurobiology, Dept. of Biology-Chemistry-Pharmacy, Freie Universität Berlin, 14195 Berlin
| | - Dietmar Kuhl
- Molecular Neurobiology, Dept. of Biology-Chemistry-Pharmacy, Freie Universität Berlin, 14195 Berlin
| | - Richard L. Huganir
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular and Molecular Medicine Graduate Program, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Paul F. Worley
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular and Molecular Medicine Graduate Program, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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48
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Rial Verde EM, Lee-Osbourne J, Worley PF, Malinow R, Cline HT. Increased expression of the immediate-early gene arc/arg3.1 reduces AMPA receptor-mediated synaptic transmission. Neuron 2006; 52:461-74. [PMID: 17088212 PMCID: PMC3951199 DOI: 10.1016/j.neuron.2006.09.031] [Citation(s) in RCA: 325] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 06/24/2005] [Accepted: 08/18/2006] [Indexed: 11/19/2022]
Abstract
Arc/Arg3.1 is an immediate-early gene whose expression levels are increased by strong synaptic activation, including synapse-strengthening activity patterns. Arc/Arg3.1 mRNA is transported to activated dendritic regions, conferring the distribution of Arc/Arg3.1 protein both temporal correlation with the inducing stimulus and spatial specificity. Here, we investigate the effect of increased Arc/Arg3.1 levels on synaptic transmission. Surprisingly, Arc/Arg3.1 reduces the amplitude of synaptic currents mediated by AMPA-type glutamate receptors (AMPARs). This effect is prevented by RNAi knockdown of Arc/Arg3.1, by deleting a region of Arc/Arg3.1 known to interact with endophilin 3 or by blocking clathrin-coated endocytosis of AMPARs. In the hippocampal slice, Arc/Arg3.1 results in removal of AMPARs composed of GluR2 and GluR3 subunits (GluR2/3). Finally, Arc/Arg3.1 expression occludes NMDAR-dependent long-term depression. Our results demonstrate that Arc/Arg3.1 reduces the number of GluR2/3 receptors leading to a decrease in AMPAR-mediated synaptic currents, consistent with a role in the homeostatic regulation of synaptic strength.
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Affiliation(s)
- Emiliano M. Rial Verde
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Jane Lee-Osbourne
- Graduate Program in Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11790
| | | | - Roberto Malinow
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Hollis T. Cline
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
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Abstract
Neurons are among the largest and most complex cells in the body. Their immense size and intricate geometry pose many unique cell-biological problems. How is dendritic architecture established and maintained? How do neurons traffic newly synthesized integral membrane proteins over such long distances to synapses? Functionally, protein trafficking to and from the postsynaptic membrane has emerged as a key mechanism underlying various forms of synaptic plasticity. Which organelles are involved in postsynaptic trafficking, and how do they integrate and respond to activity at individual synapses? Here we review what is currently known about long-range trafficking of newly synthesized postsynaptic proteins as well as the local rules that govern postsynaptic trafficking at individual synapses.
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Affiliation(s)
- Matthew J Kennedy
- Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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50
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Abstract
Homeostasis is a specialized form of regulation that precisely maintains the function of a system at a set point level of activity. Recently, homeostatic signaling has been suggested to control neural activity through the modulation of synaptic efficacy and membrane excitability ( Davis & Goodman 1998a, Turrigiano & Nelson 2000, Marder & Prinz 2002, Perez-Otano & Ehlers 2005 ). In this way, homeostatic signaling is thought to constrain neural plasticity and contribute to the stability of neural function over time. Using a restrictive definition of homeostasis, this review first evaluates the phenomenological and molecular evidence for homeostatic signaling in the nervous system. Then, basic principles underlying the design and molecular implementation of homeostatic signaling are reviewed on the basis of work in other, simplified biological systems such as bacterial chemotaxis and the heat shock response. Data from these systems are then discussed in the context of homeostatic signaling in the nervous system.
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Affiliation(s)
- Graeme W Davis
- Department of Biochemistry and Biophysics, Program in Neuroscience, University of California, San Francisco, California 94158-2822, USA.
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