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Fass DM, Lewis MC, Ahmad R, Szucs MJ, Zhang Q, Fleishman M, Wang D, Kim MJ, Biag J, Carr SA, Scolnick EM, Premont RT, Haggarty SJ. Brain-specific deletion of GIT1 impairs cognition and alters phosphorylation of synaptic protein networks implicated in schizophrenia susceptibility. Mol Psychiatry 2022; 27:3272-3285. [PMID: 35505090 PMCID: PMC9630168 DOI: 10.1038/s41380-022-01557-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 03/18/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022]
Abstract
Despite tremendous effort, the molecular and cellular basis of cognitive deficits in schizophrenia remain poorly understood. Recent progress in elucidating the genetic architecture of schizophrenia has highlighted the association of multiple loci and rare variants that may impact susceptibility. One key example, given their potential etiopathogenic and therapeutic relevance, is a set of genes that encode proteins that regulate excitatory glutamatergic synapses in brain. A critical next step is to delineate specifically how such genetic variation impacts synaptic plasticity and to determine if and how the encoded proteins interact biochemically with one another to control cognitive function in a convergent manner. Towards this goal, here we study the roles of GPCR-kinase interacting protein 1 (GIT1), a synaptic scaffolding and signaling protein with damaging coding variants found in schizophrenia patients, as well as copy number variants found in patients with neurodevelopmental disorders. We generated conditional neural-selective GIT1 knockout mice and found that these mice have deficits in fear conditioning memory recall and spatial memory, as well as reduced cortical neuron dendritic spine density. Using global quantitative phospho-proteomics, we revealed that GIT1 deletion in brain perturbs specific networks of GIT1-interacting synaptic proteins. Importantly, several schizophrenia and neurodevelopmental disorder risk genes are present within these networks. We propose that GIT1 regulates the phosphorylation of a network of synaptic proteins and other critical regulators of neuroplasticity, and that perturbation of these networks may contribute specifically to cognitive deficits observed in schizophrenia and neurodevelopmental disorders.
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Affiliation(s)
- Daniel M. Fass
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Chemical Neurobiology Laboratory, Center for Genomic Medicine, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Michael C. Lewis
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Sage Therapeutics, Cambridge, MA, USA
| | - Rushdy Ahmad
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA,Wyss Institute at Harvard University, Boston, MA, USA
| | - Matthew J. Szucs
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA,Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado, USA
| | - Qiangge Zhang
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Morgan Fleishman
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Dongqing Wang
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Myung Jong Kim
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jonathan Biag
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Novartis Pharmaceuticals, Cambridge, MA, USA
| | - Steven A. Carr
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA
| | - Edward M. Scolnick
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA
| | - Richard T. Premont
- Harrington Discovery Institute, Cleveland, OH, 44106, USA; Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Stephen J. Haggarty
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, Massachusetts 02142, USA,Chemical Neurobiology Laboratory, Center for Genomic Medicine, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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Martin JB, Herman K, Houssin NS, Rich W, Reilly MA, Plageman TF. Arvcf Dependent Adherens Junction Stability is Required to Prevent Age-Related Cortical Cataracts. Front Cell Dev Biol 2022; 10:840129. [PMID: 35874813 PMCID: PMC9297370 DOI: 10.3389/fcell.2022.840129] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/14/2022] [Indexed: 11/30/2022] Open
Abstract
The etiology of age-related cortical cataracts is not well understood but is speculated to be related to alterations in cell adhesion and/or the changing mechanical stresses occurring in the lens with time. The role of cell adhesion in maintaining lens transparency with age is difficult to assess because of the developmental and physiological roles that well-characterized adhesion proteins have in the lens. This report demonstrates that Arvcf, a member of the p120-catenin subfamily of catenins that bind to the juxtamembrane domain of cadherins, is an essential fiber cell protein that preserves lens transparency with age in mice. No major developmental defects are observed in the absence of Arvcf, however, cortical cataracts emerge in all animals examined older than 6-months of age. While opacities are not obvious in young animals, histological anomalies are observed in lenses at 4-weeks that include fiber cell separations, regions of hexagonal lattice disorganization, and absence of immunolabeled membranes. Compression analysis of whole lenses also revealed that Arvcf is required for their normal biomechanical properties. Immunofluorescent labeling of control and Arvcf-deficient lens fiber cells revealed a reduction in membrane localization of N-cadherin, β-catenin, and αN-catenin. Furthermore, super-resolution imaging demonstrated that the reduction in protein membrane localization is correlated with smaller cadherin nanoclusters. Additional characterization of lens fiber cell morphology with electron microscopy and high resolution fluorescent imaging also showed that the cellular protrusions of fiber cells are abnormally elongated with a reduction and disorganization of cadherin complex protein localization. Together, these data demonstrate that Arvcf is required to maintain transparency with age by mediating the stability of the N-cadherin protein complex in adherens junctions.
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Affiliation(s)
- Jessica B. Martin
- College of Optometry, The Ohio State University, Columbus, OH, United States
| | - Kenneth Herman
- College of Optometry, The Ohio State University, Columbus, OH, United States
| | - Nathalie S. Houssin
- College of Optometry, The Ohio State University, Columbus, OH, United States
| | - Wade Rich
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - Matthew A. Reilly
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
- Department of Ophthalmology and Visual Science, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Timothy F. Plageman
- College of Optometry, The Ohio State University, Columbus, OH, United States
- *Correspondence: Timothy F. Plageman Jr.,
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Abstract
The cognitive dysfunction experienced by patients with schizophrenia represents a major unmet clinical need. We believe that enhancing synaptic function and plasticity by targeting kalirin may provide a novel means to remediate these symptoms. Karilin (a protein encoded by the KALRN gene) has multiple functional domains, including two Dbl homology (DH) guanine exchange factor (GEF) domains, which act to enhance the activity of the Rho family guanosine triphosphate (GTP)-ases. Here, we provide an overview of kalirin's roles in brain function and its therapeutic potential in schizophrenia. We outline how it mediates diverse effects via a suite of distinct isoforms that couple to members of the Rho GTPase family to regulate synapse formation and stabilisation, and how genomic and post-mortem data implicate it in schizophrenia. We then review the current state of knowledge about the influence of kalirin on brain function at a systems level, based largely on evidence from transgenic mouse models, which support its proposed role in regulating dendritic spine function and plasticity. We demonstrate that, whilst the GTPases are classically considered to be 'undruggable', targeting kalirin and other Rho GEFs provides a means to indirectly modulate their activity. Finally, we integrate across the information presented to assess the therapeutic potential of kalirin for schizophrenia and highlight the key outstanding questions required to advance it in this capacity; namely, the need for more information about the diversity and function of its isoforms, how these change across neurodevelopment, and how they affect brain function in vivo.
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Pütz SM, Kram J, Rauh E, Kaiser S, Toews R, Lueningschroer-Wang Y, Rieger D, Raabe T. Loss of p21-activated kinase Mbt/PAK4 causes Parkinson-like phenotypes in Drosophila. Dis Model Mech 2021; 14:dmm047811. [PMID: 34125184 PMCID: PMC8246267 DOI: 10.1242/dmm.047811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/10/2021] [Indexed: 11/23/2022] Open
Abstract
Parkinson's disease (PD) provokes bradykinesia, resting tremor, rigidity and postural instability, and also non-motor symptoms such as depression, anxiety, sleep and cognitive impairments. Similar phenotypes can be induced in Drosophila melanogaster through modification of PD-relevant genes or the administration of PD-inducing toxins. Recent studies correlated deregulation of human p21-activated kinase 4 (PAK4) with PD, leaving open the question of a causative relationship of mutations in this gene for manifestation of PD symptoms. To determine whether flies lacking the PAK4 homolog Mushroom bodies tiny (Mbt) show PD-like phenotypes, we tested for a variety of PD criteria. Here, we demonstrate that mbt mutant flies show PD-like phenotypes including age-dependent movement deficits, reduced life expectancy and fragmented sleep. They also react to a stressful situation with higher immobility, indicating an influence of Mbt on emotional behavior. Loss of Mbt function has a negative effect on the number of dopaminergic protocerebral anterior medial (PAM) neurons, most likely caused by a proliferation defect of neural progenitors. The age-dependent movement deficits are not accompanied by a corresponding further loss of PAM neurons. Previous studies highlighted the importance of a small PAM subgroup for age-dependent PD motor impairments. We show that impaired motor skills are caused by a lack of Mbt in this PAM subgroup. In addition, a broader re-expression of Mbt in PAM neurons improves life expectancy. Conversely, selective Mbt knockout in the same cells shortens lifespan. We conclude that mutations in Mbt/PAK4 can play a causative role in the development of PD phenotypes.
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Affiliation(s)
- Stephanie M. Pütz
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Jette Kram
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Elisa Rauh
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Sophie Kaiser
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Romy Toews
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Yi Lueningschroer-Wang
- Neurobiology and Genetics, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Dirk Rieger
- Neurobiology and Genetics, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
| | - Thomas Raabe
- Medical Radiation and Cell Research, Biocenter, Am Hubland, University of Würzburg, D-97074 Würzburg, Germany
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5
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Stress-Sensitive Protein Rac1 and Its Involvement in Neurodevelopmental Disorders. Neural Plast 2020; 2020:8894372. [PMID: 33299404 PMCID: PMC7707960 DOI: 10.1155/2020/8894372] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/01/2020] [Accepted: 11/12/2020] [Indexed: 02/07/2023] Open
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1) is a small GTPase that is well known for its sensitivity to the environmental stress of a cell or an organism. It senses the external signals which are transmitted from membrane-bound receptors and induces downstream signaling cascades to exert its physiological functions. Rac1 is an important regulator of a variety of cellular processes, such as cytoskeletal organization, generation of oxidative products, and gene expression. In particular, Rac1 has a significant influence on certain brain functions like neuronal migration, synaptic plasticity, and memory formation via regulation of actin dynamics in neurons. Abnormal Rac1 expression and activity have been observed in multiple neurological diseases. Here, we review recent findings to delineate the role of Rac1 signaling in neurodevelopmental disorders associated with abnormal spine morphology, synaptogenesis, and synaptic plasticity. Moreover, certain novel inhibitors of Rac1 and related pathways are discussed as potential avenues toward future treatment for these diseases.
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Tomorsky J, Parker PRL, Doe CQ, Niell CM. Precise levels of nectin-3 are required for proper synapse formation in postnatal visual cortex. Neural Dev 2020; 15:13. [PMID: 33160402 PMCID: PMC7648993 DOI: 10.1186/s13064-020-00150-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Developing cortical neurons express a tightly choreographed sequence of cytoskeletal and transmembrane proteins to form and strengthen specific synaptic connections during circuit formation. Nectin-3 is a cell-adhesion molecule with previously described roles in synapse formation and maintenance. This protein and its binding partner, nectin-1, are selectively expressed in upper-layer neurons of mouse visual cortex, but their role in the development of cortical circuits is unknown. METHODS Here we block nectin-3 expression (via shRNA) or overexpress nectin-3 in developing layer 2/3 visual cortical neurons using in utero electroporation. We then assay dendritic spine densities at three developmental time points: eye opening (postnatal day (P)14), one week following eye opening after a period of heightened synaptogenesis (P21), and at the close of the critical period for ocular dominance plasticity (P35). RESULTS Knockdown of nectin-3 beginning at E15.5 or ~ P19 increased dendritic spine densities at P21 or P35, respectively. Conversely, overexpressing full length nectin-3 at E15.5 decreased dendritic spine densities when all ages were considered together. The effects of nectin-3 knockdown and overexpression on dendritic spine densities were most significant on proximal secondary apical dendrites. Interestingly, an even greater decrease in dendritic spine densities, particularly on basal dendrites at P21, was observed when we overexpressed nectin-3 lacking its afadin binding domain. CONCLUSION These data collectively suggest that the proper levels and functioning of nectin-3 facilitate normal synapse formation after eye opening on apical and basal dendrites in layer 2/3 of visual cortex.
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Affiliation(s)
- Johanna Tomorsky
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA.
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA.
- Stanford University, 318 Campus Drive, Stanford, CA, 94305, USA.
| | - Philip R L Parker
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Chris Q Doe
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
- Howard Hughes Medical Institute, University of Oregon, Eugene, OR, 97403, USA
| | - Cristopher M Niell
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA.
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA.
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Liu W, Xu B, Xue W, Yang B, Fan Y, Chen B, Xiao Z, Xue X, Sun Z, Shu M, Zhang Q, Shi Y, Zhao Y, Dai J. A functional scaffold to promote the migration and neuronal differentiation of neural stem/progenitor cells for spinal cord injury repair. Biomaterials 2020; 243:119941. [DOI: 10.1016/j.biomaterials.2020.119941] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/26/2020] [Accepted: 03/04/2020] [Indexed: 02/06/2023]
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Paskus JD, Herring BE, Roche KW. Kalirin and Trio: RhoGEFs in Synaptic Transmission, Plasticity, and Complex Brain Disorders. Trends Neurosci 2020; 43:505-518. [PMID: 32513570 DOI: 10.1016/j.tins.2020.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/15/2020] [Accepted: 05/05/2020] [Indexed: 02/07/2023]
Abstract
Changes in the actin cytoskeleton are a primary mechanism mediating the morphological and functional plasticity that underlies learning and memory. The synaptic Ras homologous (Rho) guanine nucleotide exchange factors (GEFs) Kalirin and Trio have emerged as central regulators of actin dynamics at the synapse. The increased attention surrounding Kalirin and Trio stems from the growing evidence for their roles in the etiology of a wide range of neurodevelopmental and neurodegenerative disorders. In this Review, we discuss recent findings revealing the unique and diverse functions of these paralog proteins in neurodevelopment, excitatory synaptic transmission, and plasticity. We additionally survey the growing literature implicating these proteins in various neurological disorders.
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Affiliation(s)
- Jeremiah D Paskus
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
| | - Bruce E Herring
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Katherine W Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
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9
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Basu S, Nandy A, Biswas D. Keeping RNA polymerase II on the run: Functions of MLL fusion partners in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194563. [PMID: 32348849 DOI: 10.1016/j.bbagrm.2020.194563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
Since the identification of key MLL fusion partners as transcription elongation factors regulating expression of HOX cluster genes during hematopoiesis, extensive work from the last decade has resulted in significant progress in our overall mechanistic understanding of role of MLL fusion partner proteins in transcriptional regulation of diverse set of genes beyond just the HOX cluster. In this review, we are going to detail overall understanding of role of MLL fusion partner proteins in transcriptional regulation and thus provide mechanistic insights into possible MLL fusion protein-mediated transcriptional misregulation leading to aberrant hematopoiesis and leukemogenesis.
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Affiliation(s)
- Subham Basu
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Arijit Nandy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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Jones KA, Sumiya M, Woolfrey KM, Srivastava DP, Penzes P. Loss of EPAC2 alters dendritic spine morphology and inhibitory synapse density. Mol Cell Neurosci 2019; 98:19-31. [PMID: 31059774 PMCID: PMC6639166 DOI: 10.1016/j.mcn.2019.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/04/2019] [Accepted: 05/01/2019] [Indexed: 12/31/2022] Open
Abstract
EPAC2 is a guanine nucleotide exchange factor that regulates GTPase activity of the small GTPase Rap and Ras and is highly enriched at synapses. Activation of EPAC2 has been shown to induce dendritic spine shrinkage and increase spine motility, effects that are necessary for synaptic plasticity. These morphological effects are dysregulated by rare mutations of Epac2 associated with autism spectrum disorders. In addition, EPAC2 destabilizes synapses through the removal of synaptic GluA2/3-containing AMPA receptors. Previous work has shown that Epac2 knockout mice (Epac2−/−) display abnormal social interactions, as well as gross disorganization of the frontal cortex and abnormal spine motility in vivo. In this study we sought to further understand the cellular consequences of knocking out Epac2 on the development of neuronal and synaptic structure and organization of cortical neurons. Using primary cortical neurons generated from Epac2+/+ or Epac2−/− mice, we confirm that EPAC2 is required for cAMP-dependent spine shrinkage. Neurons from Epac2−/− mice also displayed increased synaptic expression of GluA2/3-containing AMPA receptors, as well as of the adhesion protein N-cadherin. Intriguingly, analysis of excitatory and inhibitory synaptic proteins revealed that loss of EPAC2 resulted in altered expression of vesicular GABA transporter (VGAT) but not vesicular glutamate transporter 1 (VGluT1), indicating an altered ratio of excitatory and inhibitory synapses onto neurons. Finally, examination of cortical neurons located within the anterior cingulate cortex further revealed subtle deficits in the establishment of dendritic arborization in vivo. These data provide evidence that loss of EPAC2 enhances the stability of excitatory synapses and increases the number of inhibitory inputs. EPAC2 is required for cAMP-dependent spine remodeling. Loss of EPAC2 results in over-stabilized excitatory synapses. Loss of EPAC2 results in an increase in inhibitory input onto neurons. EPAC2 is required for correct dendritic arborization and spine formation in vivo.
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Affiliation(s)
- Kelly A Jones
- Department of Physiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK
| | - Michiko Sumiya
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
| | - Kevin M Woolfrey
- Department of Physiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK
| | - Deepak P Srivastava
- Department of Physiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK.
| | - Peter Penzes
- Department of Physiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 8NU, UK; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
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11
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Pütz SM. Mbt/PAK4 together with SRC modulates N-Cadherin adherens junctions in the developing Drosophila eye. Biol Open 2019; 8:8/3/bio038406. [PMID: 30885947 PMCID: PMC6451336 DOI: 10.1242/bio.038406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Tissue morphogenesis is accompanied by changes of adherens junctions (AJ). During Drosophila eye development, AJ reorganization includes the formation of isolated N-Cadherin AJ between photoreceptors R3/R4. Little is known about how these N-Cadherin AJ are established and maintained. This study focuses on the kinases Mbt/PAK4 and SRC, both known to alter E-Cadherin AJ across phyla. Drosophila p21-activated kinase Mbt and the non-receptor tyrosine kinases Src64 and Src42 regulate proper N-Cadherin AJ. N-Cadherin AJ elongation depends on SRC kinase activity. Cell culture experiments demonstrate binding of both Drosophila SRC isoforms to N-Cadherin and its subsequent tyrosine phosphorylation. In contrast, Mbt stabilizes but does not bind N-Cadherin in vitro. Mbt is required in R3/R4 for zipping the N-Cadherin AJ between these cells, independent of its kinase activity and Cdc42-binding. The mbt phenotype can be reverted by mutations in Src64 and Src42. Because Mbt neither directly binds to SRC proteins nor has a reproducible influence on their kinase activity, the conclusion is that Mbt and SRC signaling converge on N-Cadherin. N-Cadherin AJ formation during eye development requires a proper balance between the promoting effects of Mbt and the inhibiting influences of SRC kinases. Summary: N-Cadherin adherens junction formation in the Drosophila larval eye imaginal disc is controlled by the combined functions of the p21-activated kinase Mbt/PAK4 and the kinases Src64 and Src42.
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Affiliation(s)
- Stephanie M Pütz
- Institute of Medical Radiation and Cell Research, University of Würzburg, Biozentrum, Am Hubland, D-97074 Würzburg, Germany
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12
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Li Y, Zhang L, Wang C, Tang X, Chen Y, Wang X, Su L, Hu N, Xie K, Yu Y, Wang G. Sevoflurane-induced learning deficits and spine loss via nectin-1/corticotrophin-releasing hormone receptor type 1 signaling. Brain Res 2018; 1710:188-198. [PMID: 30529655 DOI: 10.1016/j.brainres.2018.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 12/15/2022]
Abstract
In recent years, the neurotoxicity of general anesthetics in the developing brain has been studied and raised great concern as a major health issue to the public and physicians. Sevoflurane inhalation may induce neurotoxicity expressed as memory and learning impairment in young animals. In the current study, we investigated the role of nectin-1 and corticotrophin-releasing hormone receptor type 1 (CRHR1) in sevoflurane-induced learning deficits and dendritic spines loss in neonatal mice. Neonatal mice (P7) were treated with 3% sevoflurane with 60% O2 or 60% O2 for 6 h. Cognitive function was evaluated by Y Maze, Object recognition test, and Morris Water Maze. Hippocampal nectin-1 and L-afadin expression assessed using western blot analysis. The dendritic spines morphology of the hippocampus was determined using Golgi impregnation on 7 d and 2 months old. Sevoflurane exposed to neonatal mice decreased hippocampal nectin-1 levels from 1 h to 2 months after sevoflurane inhalation and attenuated working and spatial memory and spinal number in adulthood, which could be reversed by nectin-1 overexpression and CRHR1 antagonist Antalarmin. Nectin-1 knockdown caused spatial learning deficits and dendritic spine loss and lower L-afadin protein expression. Sevoflurane-induced nectin-1 and L-afadin expression decrease was mediated by CRHR1 signaling in the hippocampus. This information can be used to develop targeted intervention aimed at decreasing the neurotoxicity of sevoflurane inhalation.
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Affiliation(s)
- Yize Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Linlin Zhang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Chunyan Wang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Xiaohong Tang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Yi Chen
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Xin Wang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Lin Su
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Nan Hu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Keliang Xie
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Guolin Wang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Research Institute of Anesthesiology, Tianjin 300052, China.
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Sellers KJ, Watson IA, Gresz RE, Raval P, Srivastava DP. Cyto-nuclear shuttling of afadin is required for rapid estradiol-mediated modifications of histone H3. Neuropharmacology 2018; 143:153-162. [PMID: 30268521 PMCID: PMC6277849 DOI: 10.1016/j.neuropharm.2018.09.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/18/2018] [Accepted: 09/25/2018] [Indexed: 12/19/2022]
Abstract
Estrogens have been shown to rapidly regulate local signalling at synapses and within the nucleus. The result of these signalling events is to rapidly modulate synapse structure and function, as well as epigenetic mechanisms including histone modifications. Ultimately these mechanisms are thought to contribute to long-lasting changes in neural circuitry, and thus influence cognitive functions such as learning and memory. However, the mechanisms by which estrogen-mediated local synaptic and nuclear signalling events are coordinated are not well understood. In this study we have found that the scaffold protein afadin, (also known as AF-6), undergoes a bi-directional trafficking to both synaptic and nuclear compartment in response to acute 17β-estradiol (estradiol) treatment, in mixed sex neuronal cultures derived from fetal cortex. Interestingly, nuclear accumulation of afadin was coincidental with an increase in the phosphorylation of histone H3 at serine 10 (H3S10p). This epigenetic modification is associated with the remodeling of chromatin into an open euchromatin state, allowing for transcriptional activation and related learning and memory processes. Critically, the cyto-nuclear trafficking of afadin was required for estradiol-dependent H3S10p. We further determined that nuclear accumulation of afadin is sufficient to induce phosphorylation of the mitogentic kinases ERK1/2 (pERK1/2) within the nucleus. Moreover, nuclear pERK1/2 was required for estradiol-dependent H3S10p. Taken together, we propose a model whereby estradiol induces the bi-directional trafficking of afadin to synaptic and nuclear sub-compartments. Within the nucleus, afadin is required for increased pERK1/2 which in turn is required for H3S10p. Therefore this represents a mechanism through which estrogens may be able to coordinate both synaptic and nucleosomal events within the same neuronal population. 17β-estradiol targets afadin to membrane and nuclear subcompartments. Histone H3 is rapidly phosphorylated by 17β-estradiol. Histone H3 phosphorylation by 17β-estradiol requires afadin nuclear accumulation. 17β-estradiol-mediated ERK1/2 activation is required for histone H3 phosphorylation.
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Affiliation(s)
- Katherine J Sellers
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE5 9RT, UK
| | - Iain A Watson
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE5 9RT, UK
| | - Rahel E Gresz
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE5 9RT, UK
| | - Pooja Raval
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE5 9RT, UK
| | - Deepak P Srivastava
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE5 9RT, UK.
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14
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Seipold L, Altmeppen H, Koudelka T, Tholey A, Kasparek P, Sedlacek R, Schweizer M, Bär J, Mikhaylova M, Glatzel M, Saftig P. In vivo regulation of the A disintegrin and metalloproteinase 10 (ADAM10) by the tetraspanin 15. Cell Mol Life Sci 2018; 75:3251-3267. [PMID: 29520422 PMCID: PMC11105247 DOI: 10.1007/s00018-018-2791-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/26/2018] [Accepted: 03/06/2018] [Indexed: 12/26/2022]
Abstract
A disintegrin and metalloproteinase 10 (ADAM10) plays a major role in the ectodomain shedding of important surface molecules with physiological and pathological relevance including the amyloid precursor protein (APP), the cellular prion protein, and different cadherins. Despite its therapeutic potential, there is still a considerable lack of knowledge how this protease is regulated. We have previously identified tetraspanin15 (Tspan15) as a member of the TspanC8 family to specifically associate with ADAM10. Cell-based overexpression experiments revealed that this binding affected the maturation process and surface expression of the protease. Our current study shows that Tspan15 is abundantly expressed in mouse brain, where it specifically interacts with endogenous ADAM10. Tspan15 knockout mice did not reveal an overt phenotype but showed a pronounced decrease of the active and mature form of ADAM10, an effect which augmented with aging. The decreased expression of active ADAM10 correlated with an age-dependent reduced shedding of neuronal (N)-cadherin and the cellular prion protein. APP α-secretase cleavage and the expression of Notch-dependent genes were not affected by the loss of Tspan15, which is consistent with the hypothesis that different TspanC8s cause ADAM10 to preferentially cleave particular substrates. Analyzing spine morphology revealed no obvious differences between Tspan15 knockout and wild-type mice. However, Tspan15 expression was elevated in brains of an Alzheimer's disease mouse model and of patients, suggesting that upregulation of Tspan15 expression reflects a cellular response in a disease state. In conclusion, our data show that Tspan15 and most likely also other members of the TspanC8 family are central modulators of ADAM10-mediated ectodomain shedding in vivo.
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Affiliation(s)
- Lisa Seipold
- Institute of Biochemistry, Christian Albrechts University Kiel, Olshausenstrasse 40, 24118, Kiel, Germany
| | - Hermann Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Tomas Koudelka
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Christian Albrechts University Kiel, Niemannsweg 11, Kiel, 24105, Germany
| | - Andreas Tholey
- Systematic Proteome Research and Bioanalytics, Institute for Experimental Medicine, Christian Albrechts University Kiel, Niemannsweg 11, Kiel, 24105, Germany
| | - Petr Kasparek
- Czech Centre for Phenogenomics and Laboratory of Transgenic Models of Diseases, Division BIOCEV, Institute of Molecular Genetics of the CAS, v. v. i, Vestec, Czech Republic
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics and Laboratory of Transgenic Models of Diseases, Division BIOCEV, Institute of Molecular Genetics of the CAS, v. v. i, Vestec, Czech Republic
| | - Michaela Schweizer
- Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251, Hamburg, Germany
| | - Julia Bär
- Center for Molecular Neurobiology Hamburg (ZMNH), Emmy-Noether Group "Neuronal Protein Transport", University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251, Hamburg, Germany
| | - Marina Mikhaylova
- Center for Molecular Neurobiology Hamburg (ZMNH), Emmy-Noether Group "Neuronal Protein Transport", University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251, Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Paul Saftig
- Institute of Biochemistry, Christian Albrechts University Kiel, Olshausenstrasse 40, 24118, Kiel, Germany.
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15
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Sai K, Wang S, Kaito A, Fujiwara T, Maruo T, Itoh Y, Miyata M, Sakakibara S, Miyazaki N, Murata K, Yamaguchi Y, Haruta T, Nishioka H, Motojima Y, Komura M, Kimura K, Mandai K, Takai Y, Mizoguchi A. Multiple roles of afadin in the ultrastructural morphogenesis of mouse hippocampal mossy fiber synapses. J Comp Neurol 2017; 525:2719-2734. [PMID: 28498492 DOI: 10.1002/cne.24238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 04/24/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022]
Abstract
A hippocampal mossy fiber synapse, which is implicated in learning and memory, has a complex structure in which mossy fiber boutons attach to the dendritic shaft by puncta adherentia junctions (PAJs) and wrap around a multiply-branched spine, forming synaptic junctions. Here, we electron microscopically analyzed the ultrastructure of this synapse in afadin-deficient mice. Transmission electron microscopy analysis revealed that typical PAJs with prominent symmetrical plasma membrane darkening undercoated with the thick filamentous cytoskeleton were observed in the control synapse, whereas in the afadin-deficient synapse, atypical PAJs with the symmetrical plasma membrane darkening, which was much less in thickness and darkness than those of the control typical PAJs, were observed. Immunoelectron microscopy analysis revealed that nectin-1, nectin-3, and N-cadherin were localized at the control typical PAJs, whereas nectin-1 and nectin-3 were localized at the afadin-deficient atypical PAJs to extents lower than those in the control synapse and N-cadherin was localized at their nonjunctional flanking regions. These results indicate that the atypical PAJs are formed by nectin-1 and nectin-3 independently of afadin and N-cadherin and that the typical PAJs are formed by afadin and N-cadherin cooperatively with nectin-1 and nectin-3. Serial block face-scanning electron microscopy analysis revealed that the complexity of postsynaptic spines and mossy fiber boutons, the number of spine heads, the area of postsynaptic densities, and the density of synaptic vesicles docked to active zones were decreased in the afadin-deficient synapse. These results indicate that afadin plays multiple roles in the complex ultrastructural morphogenesis of hippocampal mossy fiber synapses.
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Affiliation(s)
- Kousyoku Sai
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan
| | - Shujie Wang
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan.,CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan
| | - Aika Kaito
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan
| | - Takeshi Fujiwara
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan.,CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan
| | - Tomohiko Maruo
- CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan.,Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0047, Japan
| | - Yu Itoh
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0047, Japan
| | - Shotaro Sakakibara
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0047, Japan
| | - Naoyuki Miyazaki
- National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Yuuki Yamaguchi
- SM Application Department, JEOL Ltd., Akishima, Tokyo, 196-8556, Japan
| | - Tomohiro Haruta
- EM Application Department, JEOL Ltd., Akishima, Tokyo, 196-8556, Japan
| | - Hideo Nishioka
- EM Application Department, JEOL Ltd., Akishima, Tokyo, 196-8556, Japan
| | - Yuki Motojima
- Scientific Solutions Department, Olympus Corp., Tokyo, 163-0914, Japan
| | - Miyuki Komura
- Scientific Solutions Department, Olympus Corp., Tokyo, 163-0914, Japan
| | - Kazushi Kimura
- Faculty of Human Science, Department of Physical Therapy, Hokkaido Bunkyo University, Eniwa, Hokkaido, 061-1449, Japan
| | - Kenji Mandai
- CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan.,Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0047, Japan
| | - Yoshimi Takai
- CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan.,Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0047, Japan
| | - Akira Mizoguchi
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan.,CREST, Japan Science and Technology Agency, Kobe, Hyogo, 650-0047, Japan
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16
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Putative Cell Adhesion Membrane Protein Vstm5 Regulates Neuronal Morphology and Migration in the Central Nervous System. J Neurosci 2016; 36:10181-97. [PMID: 27683913 DOI: 10.1523/jneurosci.0541-16.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 08/16/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED During brain development, dynamic changes in neuronal membranes perform critical roles in neuronal morphogenesis and migration to create functional neural circuits. Among the proteins that induce membrane dynamics, cell adhesion molecules are important in neuronal membrane plasticity. Here, we report that V-set and transmembrane domain-containing protein 5 (Vstm5), a cell-adhesion-like molecule belonging to the Ig superfamily, was found in mouse brain. Knock-down of Vstm5 in cultured hippocampal neurons markedly reduced the complexity of dendritic structures, as well as the number of dendritic filopodia. Vstm5 also regulates neuronal morphology by promoting dendritic protrusions that later develop into dendritic spines. Using electroporation in utero, we found that Vstm5 overexpression delayed neuronal migration and induced multiple branches in leading processes during corticogenesis. These results indicate that Vstm5 is a new cell-adhesion-like molecule and is critically involved in synaptogenesis and corticogenesis by promoting neuronal membrane dynamics. SIGNIFICANCE STATEMENT Neuronal migration and morphogenesis play critical roles in brain development and function. In this study, we demonstrate for the first time that V-set and transmembrane domain-containing protein 5 (Vstm5), a putative cell adhesion membrane protein, modulates both the position and complexity of central neurons by altering their membrane morphology and dynamics. Vstm5 is also one of the target genes responsible for variations in patient responses to treatments for major depressive disorder. Our results provide the first evidence that Vstm5 is a novel factor involved in the modulation of the neuronal membrane and a critical element in normal neural circuit formation during mammalian brain development.
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17
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Kumar A, Paeger L, Kosmas K, Kloppenburg P, Noegel AA, Peche VS. Neuronal Actin Dynamics, Spine Density and Neuronal Dendritic Complexity Are Regulated by CAP2. Front Cell Neurosci 2016; 10:180. [PMID: 27507934 PMCID: PMC4960234 DOI: 10.3389/fncel.2016.00180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022] Open
Abstract
Actin remodeling is crucial for dendritic spine development, morphology and density. CAP2 is a regulator of actin dynamics through sequestering G-actin and severing F-actin. In a mouse model, ablation of CAP2 leads to cardiovascular defects and delayed wound healing. This report investigates the role of CAP2 in the brain using Cap2gt/gt mice. Dendritic complexity, the number and morphology of dendritic spines were altered in Cap2gt/gt with increased number of excitatory synapses. This was accompanied by increased F-actin content and F-actin accumulation in cultured Cap2gt/gt neurons. Moreover, reduced surface GluA1 was observed in mutant neurons under basal condition and after induction of chemical LTP. Additionally, we show an interaction between CAP2 and n-cofilin, presumably mediated through the C-terminal domain of CAP2 and dependent on cofilin Ser3 phosphorylation. In vivo, the consequences of this interaction were altered phosphorylated cofilin levels and formation of cofilin aggregates in the neurons. Thus, our studies identify a novel role of CAP2 in neuronal development and neuronal actin dynamics.
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Affiliation(s)
- Atul Kumar
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Lars Paeger
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany; Biocenter, Institute for Zoology, University of Cologne, CologneGermany
| | - Kosmas Kosmas
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Peter Kloppenburg
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany; Biocenter, Institute for Zoology, University of Cologne, CologneGermany
| | - Angelika A Noegel
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Vivek S Peche
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
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18
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Brown JC, Petersen A, Zhong L, Himelright ML, Murphy JA, Walikonis RS, Gerges NZ. Bidirectional regulation of synaptic transmission by BRAG1/IQSEC2 and its requirement in long-term depression. Nat Commun 2016; 7:11080. [PMID: 27009485 PMCID: PMC4820844 DOI: 10.1038/ncomms11080] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/16/2016] [Indexed: 01/09/2023] Open
Abstract
Dysfunction of the proteins regulating synaptic function can cause synaptic plasticity imbalance that underlies neurological disorders such as intellectual disability. A study found that four distinct mutations within BRAG1, an Arf-GEF synaptic protein, each led to X-chromosome-linked intellectual disability (XLID). Although the physiological functions of BRAG1 are poorly understood, each of these mutations reduces BRAG1's Arf-GEF activity. Here we show that BRAG1 is required for the activity-dependent removal of AMPA receptors in rat hippocampal pyramidal neurons. Moreover, we show that BRAG1 bidirectionally regulates synaptic transmission. On one hand, BRAG1 is required for the maintenance of synaptic transmission. On the other hand, BRAG1 expression enhances synaptic transmission, independently of BRAG1 Arf-GEF activity or neuronal activity, but dependently on its C-terminus interactions. This study demonstrates a dual role of BRAG1 in synaptic function and highlights the functional relevance of reduced BRAG1 Arf-GEF activity as seen in the XLID-associated human mutations.
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Affiliation(s)
- Joshua C Brown
- Department of Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin 53132 USA
| | - Amber Petersen
- Department of Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin 53132 USA
| | - Ling Zhong
- Department of Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin 53132 USA
| | - Miranda L Himelright
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269 USA
| | - Jessica A Murphy
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269 USA
| | - Randall S Walikonis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269 USA
| | - Nashaat Z Gerges
- Department of Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin 53132 USA
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19
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Control of Dendritic Spine Morphological and Functional Plasticity by Small GTPases. Neural Plast 2016; 2016:3025948. [PMID: 26989514 PMCID: PMC4775798 DOI: 10.1155/2016/3025948] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 01/06/2016] [Accepted: 01/19/2016] [Indexed: 11/18/2022] Open
Abstract
Structural plasticity of excitatory synapses is a vital component of neuronal development, synaptic plasticity, and behaviour. Abnormal development or regulation of excitatory synapses has also been strongly implicated in many neurodevelopmental, psychiatric, and neurodegenerative disorders. In the mammalian forebrain, the majority of excitatory synapses are located on dendritic spines, specialized dendritic protrusions that are enriched in actin. Research over recent years has begun to unravel the complexities involved in the regulation of dendritic spine structure. The small GTPase family of proteins have emerged as key regulators of structural plasticity, linking extracellular signals with the modulation of dendritic spines, which potentially underlies their ability to influence cognition. Here we review a number of studies that examine how small GTPases are activated and regulated in neurons and furthermore how they can impact actin dynamics, and thus dendritic spine morphology. Elucidating this signalling process is critical for furthering our understanding of the basic mechanisms by which information is encoded in neural circuits but may also provide insight into novel targets for the development of effective therapies to treat cognitive dysfunction seen in a range of neurological disorders.
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20
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Gouder L, Tinevez JY, Goubran-Botros H, Benchoua A, Bourgeron T, Cloëz-Tayarani I. Three-dimensional Quantification of Dendritic Spines from Pyramidal Neurons Derived from Human Induced Pluripotent Stem Cells. J Vis Exp 2015. [PMID: 26484791 DOI: 10.3791/53197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are distributed along the dendrites. Their morphology is largely dependent on neuronal activity, and they are dynamic. Dendritic spines express glutamatergic receptors (AMPA and NMDA receptors) on their surface and at the levels of postsynaptic densities. Each spine allows the neuron to control its state and local activity independently. Spine morphologies have been extensively studied in glutamatergic pyramidal cells of the brain cortex, using both in vivo approaches and neuronal cultures obtained from rodent tissues. Neuropathological conditions can be associated to altered spine induction and maturation, as shown in rodent cultured neurons and one-dimensional quantitative analysis (1). The present study describes a protocol for the 3D quantitative analysis of spine morphologies using human cortical neurons derived from neural stem cells (late cortical progenitors). These cells were initially obtained from induced pluripotent stem cells. This protocol allows the analysis of spine morphologies at different culture periods, and with possible comparison between induced pluripotent stem cells obtained from control individuals with those obtained from patients with psychiatric diseases.
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Affiliation(s)
- Laura Gouder
- Human Genetics and Cognitive Functions, Institut Pasteur; CNRS URA 2182 'Genes, synapses and cognition', Institut Pasteur; Human Genetics and Cognitive Functions, Université Paris Diderot, Sorbonne Paris Cité
| | - Jean-Yves Tinevez
- Plateforme d' Imagerie Dynamique, Imagopole, CiTech, Institut Pasteur
| | - Hany Goubran-Botros
- Human Genetics and Cognitive Functions, Institut Pasteur; CNRS URA 2182 'Genes, synapses and cognition', Institut Pasteur; Human Genetics and Cognitive Functions, Université Paris Diderot, Sorbonne Paris Cité
| | | | - Thomas Bourgeron
- Human Genetics and Cognitive Functions, Institut Pasteur; CNRS URA 2182 'Genes, synapses and cognition', Institut Pasteur; Human Genetics and Cognitive Functions, Université Paris Diderot, Sorbonne Paris Cité
| | - Isabelle Cloëz-Tayarani
- Human Genetics and Cognitive Functions, Institut Pasteur; CNRS URA 2182 'Genes, synapses and cognition', Institut Pasteur; Human Genetics and Cognitive Functions, Université Paris Diderot, Sorbonne Paris Cité;
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21
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Abstract
The small size of dendritic spines belies the elaborate role they play in excitatory synaptic transmission and ultimately complex behaviors. The cytoskeletal architecture of the spine is predominately composed of actin filaments. These filaments, which at first glance might appear simple, are also surprisingly complex. They dynamically assemble into different structures and serve as a platform for orchestrating the elaborate responses of the spine during spinogenesis and experience-dependent plasticity. Multiple mutations associated with human neurodevelopmental and psychiatric disorders involve genes that encode regulators of the synaptic cytoskeleton. A major, unresolved question is how the disruption of specific actin filament structures leads to the onset and progression of complex synaptic and behavioral phenotypes. This review will cover established and emerging mechanisms of actin cytoskeletal remodeling and how this influences specific aspects of spine biology that are implicated in disease.
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Affiliation(s)
| | - Scott H Soderling
- From the Departments of Cell Biology and Neurobiology, Duke University, School of Medicine, Durham, North Carolina 27710
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22
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Castañeda P, Muñoz M, García-Rojo G, Ulloa JL, Bravo JA, Márquez R, García-Pérez MA, Arancibia D, Araneda K, Rojas PS, Mondaca-Ruff D, Díaz-Véliz G, Mora S, Aliaga E, Fiedler JL. Association of N-cadherin levels and downstream effectors of Rho GTPases with dendritic spine loss induced by chronic stress in rat hippocampal neurons. J Neurosci Res 2015; 93:1476-91. [PMID: 26010004 DOI: 10.1002/jnr.23602] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 05/03/2015] [Accepted: 05/04/2015] [Indexed: 12/24/2022]
Abstract
Chronic stress promotes cognitive impairment and dendritic spine loss in hippocampal neurons. In this animal model of depression, spine loss probably involves a weakening of the interaction between pre- and postsynaptic cell adhesion molecules, such as N-cadherin, followed by disruption of the cytoskeleton. N-cadherin, in concert with catenin, stabilizes the cytoskeleton through Rho-family GTPases. Via their effector LIM kinase (LIMK), RhoA and ras-related C3 botulinum toxin substrate 1 (RAC) GTPases phosphorylate and inhibit cofilin, an actin-depolymerizing molecule, favoring spine growth. Additionally, RhoA, through Rho kinase (ROCK), inactivates myosin phosphatase through phosphorylation of the myosin-binding subunit (MYPT1), producing actomyosin contraction and probable spine loss. Some micro-RNAs negatively control the translation of specific mRNAs involved in Rho GTPase signaling. For example, miR-138 indirectly activates RhoA, and miR-134 reduces LIMK1 levels, resulting in spine shrinkage; in contrast, miR-132 activates RAC1, promoting spine formation. We evaluated whether N-cadherin/β-catenin and Rho signaling is sensitive to chronic restraint stress. Stressed rats exhibit anhedonia, impaired associative learning, and immobility in the forced swim test and reduction in N-cadherin levels but not β-catenin in the hippocampus. We observed a reduction in spine number in the apical dendrites of CA1 pyramidal neurons, with no effect on the levels of miR-132 or miR-134. Although the stress did not modify the RAC-LIMK-cofilin signaling pathway, we observed increased phospho-MYPT1 levels, probably mediated by RhoA-ROCK activation. Furthermore, chronic stress raises the levels of miR-138 in accordance with the observed activation of the RhoA-ROCK pathway. Our findings suggest that a dysregulation of RhoA-ROCK activity by chronic stress could potentially underlie spine loss in hippocampal neurons.
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Affiliation(s)
- Patricia Castañeda
- Department of Biology, Faculty of Sciences, Universidad Metropolitana de Ciencias de la Educación, Santiago, Chile
| | - Mauricio Muñoz
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Gonzalo García-Rojo
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - José L Ulloa
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Javier A Bravo
- Grupo de NeuroGastroBioquímica, Laboratorio de Química Biológica, Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Ruth Márquez
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - M Alexandra García-Pérez
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Damaris Arancibia
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Karina Araneda
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Paulina S Rojas
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - David Mondaca-Ruff
- Graduate Student PhD Program, Department of Pharmacology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Gabriela Díaz-Véliz
- Laboratorio Farmacología del Comportamiento, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio Mora
- Laboratorio Farmacología del Comportamiento, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Esteban Aliaga
- Escuela de Kinesiología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Jenny L Fiedler
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
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23
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Duman JG, Mulherkar S, Tu YK, X Cheng J, Tolias KF. Mechanisms for spatiotemporal regulation of Rho-GTPase signaling at synapses. Neurosci Lett 2015; 601:4-10. [PMID: 26003445 DOI: 10.1016/j.neulet.2015.05.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/16/2015] [Accepted: 05/18/2015] [Indexed: 01/16/2023]
Abstract
Synapses mediate information flow between neurons and undergo plastic changes in response to experience, which is critical for learning and memory. Conversely, synaptic defects impair information processing and underlie many brain pathologies. Rho-family GTPases control synaptogenesis by transducing signals from extracellular stimuli to the cytoskeleton and nucleus. The Rho-GTPases Rac1 and Cdc42 promote synapse development and the growth of axons and dendrites, while RhoA antagonizes these processes. Despite its importance, many aspects of Rho-GTPase signaling remain relatively unknown. Rho-GTPases are activated by guanine nucleotide exchange factors (GEFs) and inhibited by GTPase-activating proteins (GAPs). Though the number of both GEFs and GAPs greatly exceeds that of Rho-GTPases, loss of even a single GEF or GAP often has profound effects on cognition and behavior. Here, we explore how the actions of specific GEFs and GAPs give rise to the precise spatiotemporal activation patterns of Rho-GTPases in neurons. We consider the effects of coupling GEFs and GAPs targeting the same Rho-GTPase and the modular pathways that connect specific cellular stimuli with a given Rho-GTPase via different GEFs. We discuss how the creation of sharp borders between Rho-GTPase activation zones is achieved by pairing a GEF for one Rho-GTPase with a GAP for another and the extensive crosstalk between different Rho-GTPases. Given the importance of synapses for cognition and the fundamental roles that Rho-GTPases play in regulating them, a detailed understanding of Rho-GTPase signaling is essential to the progress of neuroscience.
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Affiliation(s)
- Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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24
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Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:632450. [PMID: 25879033 PMCID: PMC4388020 DOI: 10.1155/2015/632450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.
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25
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Huang PT, Chen CH, Hsu IU, Salim SA, Kao SH, Cheng CW, Lai CH, Lee CF, Lin YF. Huntingtin-associated protein 1 interacts with breakpoint cluster region protein to regulate neuronal differentiation. PLoS One 2015; 10:e0116372. [PMID: 25671650 PMCID: PMC4324908 DOI: 10.1371/journal.pone.0116372] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 12/08/2014] [Indexed: 01/03/2023] Open
Abstract
Alterations in microtubule-dependent trafficking and certain signaling pathways in neuronal cells represent critical pathogenesis in neurodegenerative diseases. Huntingtin (Htt)-associated protein-1 (Hap1) is a brain-enriched protein and plays a key role in the trafficking of neuronal surviving and differentiating cargos. Lack of Hap1 reduces signaling through tropomyosin-related kinases including extracellular signal regulated kinase (ERK), resulting in inhibition of neurite outgrowth, hypothalamic dysfunction and postnatal lethality in mice. To examine how Hap1 is involved in microtubule-dependent trafficking and neuronal differentiation, we performed a proteomic analysis using taxol-precipitated microtubules from Hap1-null and wild-type mouse brains. Breakpoint cluster region protein (Bcr), a Rho GTPase regulator, was identified as a Hap1-interacting partner. Bcr was co-immunoprecipitated with Hap1 from transfected neuro-2a cells and co-localized with Hap1A isoform more in the differentiated than in the nondifferentiated cells. The Bcr downstream effectors, namely ERK and p38, were significantly less activated in Hap1-null than in wild-type mouse hypothalamus. In conclusion, Hap1 interacts with Bcr on microtubules to regulate neuronal differentiation.
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Affiliation(s)
- Pai-Tsang Huang
- Department of Occupational Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chien-Ho Chen
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - I-Uen Hsu
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Shaima’a Ahmad Salim
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Shu-Huei Kao
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Chao-Wen Cheng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chang-Hao Lai
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Fan Lee
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yung-Feng Lin
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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26
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Chazeau A, Garcia M, Czöndör K, Perrais D, Tessier B, Giannone G, Thoumine O. Mechanical coupling between transsynaptic N-cadherin adhesions and actin flow stabilizes dendritic spines. Mol Biol Cell 2015; 26:859-73. [PMID: 25568337 PMCID: PMC4342023 DOI: 10.1091/mbc.e14-06-1086] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A combination of quantitative live imaging of fluorescently tagged actin, N-cadherin, and myosin in primary neurons and computer modeling of actin dynamics shows that a clutch-like mechanism connecting N-cadherin–based transsynaptic adhesions and the actin/myosin network drives the stabilization of dendritic filopodia into spines. The morphology of neuronal dendritic spines is a critical indicator of synaptic function. It is regulated by several factors, including the intracellular actin/myosin cytoskeleton and transcellular N-cadherin adhesions. To examine the mechanical relationship between these molecular components, we performed quantitative live-imaging experiments in primary hippocampal neurons. We found that actin turnover and structural motility were lower in dendritic spines than in immature filopodia and increased upon expression of a nonadhesive N-cadherin mutant, resulting in an inverse relationship between spine motility and actin enrichment. Furthermore, the pharmacological stimulation of myosin II induced the rearward motion of actin structures in spines, showing that myosin II exerts tension on the actin network. Strikingly, the formation of stable, spine-like structures enriched in actin was induced at contacts between dendritic filopodia and N-cadherin–coated beads or micropatterns. Finally, computer simulations of actin dynamics mimicked various experimental conditions, pointing to the actin flow rate as an important parameter controlling actin enrichment in dendritic spines. Together these data demonstrate that a clutch-like mechanism between N-cadherin adhesions and the actin flow underlies the stabilization of dendritic filopodia into mature spines, a mechanism that may have important implications in synapse initiation, maturation, and plasticity in the developing brain.
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Affiliation(s)
- Anaël Chazeau
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
| | - Mikael Garcia
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France CYTOO, Minatec, Grenoble, 38054 Grenoble, France
| | - Katalin Czöndör
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
| | - David Perrais
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
| | - Béatrice Tessier
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
| | - Grégory Giannone
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
| | - Olivier Thoumine
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France Interdisciplinary Institute for Neuroscience, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 5297, F-33000 Bordeaux, France
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27
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Jones KA, Eng AG, Raval P, Srivastava DP, Penzes P. Scaffold protein X11α interacts with kalirin-7 in dendrites and recruits it to Golgi outposts. J Biol Chem 2014; 289:35517-29. [PMID: 25378388 PMCID: PMC4271236 DOI: 10.1074/jbc.m114.587709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Pyramidal neurons in the mammalian forebrain receive their synaptic inputs through their dendritic trees, and dendritic spines are the sites of most excitatory synapses. Dendritic spine structure is important for brain development and plasticity. Kalirin-7 is a guanine nucleotide-exchange factor for the small GTPase Rac1 and is a critical regulator of dendritic spine remodeling. The subcellular localization of kalirin-7 is thought to be important for regulating its function in neurons. A yeast two-hybrid screen has identified the adaptor protein X11α as an interacting partner of kalirin-7. Here, we show that kalirin-7 and X11α form a complex in the brain, and this interaction is mediated by the C terminus of kalirin-7. Kalirin-7 and X11α co-localize at excitatory synapses in cultured cortical neurons. Using time-lapse imaging of fluorescence recovery after photobleaching, we show that X11α is present in a mobile fraction of the postsynaptic density. X11α also localizes to Golgi outposts in dendrites, and its overexpression induces the removal of kalirin-7 from spines and accumulation of kalirin-7 in Golgi outposts. In addition, neurons overexpressing X11α displayed thinner spines. These data support a novel mechanism of regulation of kalirin-7 localization and function in dendrites, providing insight into signaling pathways underlying neuronal plasticity. Dissecting the molecular mechanisms of synaptic structural plasticity will improve our understanding of neuropsychiatric and neurodegenerative disorders, as kalirin-7 has been associated with schizophrenia and Alzheimer disease.
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Affiliation(s)
| | - Andrew G Eng
- the Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, Illinois 60611, and
| | - Pooja Raval
- the Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King's College London, London SE5 9NU, United Kingdom
| | - Deepak P Srivastava
- From the Departments of Physiology and the Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King's College London, London SE5 9NU, United Kingdom
| | - Peter Penzes
- From the Departments of Physiology and Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611,
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28
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Tian J, Tep C, Benedick A, Saidi N, Ryu JC, Kim ML, Sadasivan S, Oberdick J, Smeyne R, Zhu MX, Yoon SO. p75 regulates Purkinje cell firing by modulating SK channel activity through Rac1. J Biol Chem 2014; 289:31458-72. [PMID: 25253694 PMCID: PMC4223344 DOI: 10.1074/jbc.m114.589937] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/11/2014] [Indexed: 12/22/2022] Open
Abstract
p75 is expressed among Purkinje cells in the adult cerebellum, but its function has remained obscure. Here we report that p75 is involved in maintaining the frequency and regularity of spontaneous firing of Purkinje cells. The overall spontaneous firing activity of Purkinje cells was increased in p75(-/-) mice during the phasic firing period due to a longer firing period and accompanying reduction in silence period than in the wild type. We attribute these effects to a reduction in small conductance Ca(2+)-activated potassium (SK) channel activity in Purkinje cells from p75(-/-) mice compared with the wild type littermates. The mechanism by which p75 regulates SK channel activity appears to involve its ability to activate Rac1. In organotypic cultures of cerebellar slices, brain-derived neurotrophic factor increased RacGTP levels by activating p75 but not TrkB. These results correlate with a reduction in RacGTP levels in synaptosome fractions from the p75(-/-) cerebellum, but not in that from the cortex of the same animals, compared with wild type littermates. More importantly, we demonstrate that Rac1 modulates SK channel activity and firing patterns of Purkinje cells. Along with the finding that spine density was reduced in p75(-/-) cerebellum, these data suggest that p75 plays a role in maintaining normalcy of Purkinje cell firing in the cerebellum in part by activating Rac1 in synaptic compartments and modulating SK channels.
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Affiliation(s)
- JinBin Tian
- the Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, the Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Chhavy Tep
- From the Department of Molecular and Cellular Biochemistry, the Biochemistry Program, and
| | - Alex Benedick
- From the Department of Molecular and Cellular Biochemistry
| | - Nabila Saidi
- From the Department of Molecular and Cellular Biochemistry
| | - Jae Cheon Ryu
- From the Department of Molecular and Cellular Biochemistry
| | - Mi Lyang Kim
- From the Department of Molecular and Cellular Biochemistry
| | - Shankar Sadasivan
- the Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, and
| | | | - Richard Smeyne
- the Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, and
| | - Michael X Zhu
- the Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, the Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Sung Ok Yoon
- From the Department of Molecular and Cellular Biochemistry,
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29
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Kobayashi R, Kurita S, Miyata M, Maruo T, Mandai K, Rikitake Y, Takai Y. s-Afadin binds more preferentially to the cell adhesion molecules nectins than l-afadin. Genes Cells 2014; 19:853-63. [DOI: 10.1111/gtc.12185] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 08/25/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Reiko Kobayashi
- Division of Pathogenetic Signaling; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0047 Japan
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Souichi Kurita
- Division of Pathogenetic Signaling; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0047 Japan
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Muneaki Miyata
- Division of Signal Transduction; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0047 Japan
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Kenji Mandai
- Division of Pathogenetic Signaling; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0047 Japan
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Yoshiyuki Rikitake
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
- Division of Signal Transduction; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0047 Japan
- Division of Molecular and Cellular Biology; Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe Hyogo 650-0017 Japan
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30
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VanLeeuwen JE, Rafalovich I, Sellers K, Jones KA, Griffith TN, Huda R, Miller RJ, Srivastava DP, Penzes P. Coordinated nuclear and synaptic shuttling of afadin promotes spine plasticity and histone modifications. J Biol Chem 2014; 289:10831-10842. [PMID: 24567331 PMCID: PMC4036196 DOI: 10.1074/jbc.m113.536391] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability of a neuron to transduce extracellular signals into long lasting changes in neuronal morphology is central to its normal function. Increasing evidence shows that coordinated regulation of synaptic and nuclear signaling in response to NMDA receptor activation is crucial for long term memory, synaptic tagging, and epigenetic signaling. Although mechanisms have been proposed for synapse-to-nuclear communication, it is unclear how signaling is coordinated at both subcompartments. Here, we show that activation of NMDA receptors induces the bi-directional and concomitant shuttling of the scaffold protein afadin from the cytosol to the nucleus and synapses. Activity-dependent afadin nuclear translocation peaked 2 h post-stimulation, was independent of protein synthesis, and occurred concurrently with dendritic spine remodeling. Moreover, activity-dependent afadin nuclear translocation coincides with phosphorylation of histone H3 at serine 10 (H3S10p), a marker of epigenetic modification. Critically, blocking afadin nuclear accumulation attenuated activity-dependent dendritic spine remodeling and H3 phosphorylation. Collectively, these data support a novel model of neuronal nuclear signaling whereby dual-residency proteins undergo activity-dependent bi-directional shuttling from the cytosol to synapses and the nucleus, coordinately regulating dendritic spine remodeling and histone modifications.
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Affiliation(s)
- Jon-Eric VanLeeuwen
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Igor Rafalovich
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Katherine Sellers
- Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
| | - Kelly A Jones
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Theanne N Griffith
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Rafiq Huda
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Richard J Miller
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Deepak P Srivastava
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611; Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom.
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
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31
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Remmers C, Sweet RA, Penzes P. Abnormal kalirin signaling in neuropsychiatric disorders. Brain Res Bull 2014; 103:29-38. [PMID: 24334022 PMCID: PMC3989394 DOI: 10.1016/j.brainresbull.2013.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 10/25/2022]
Abstract
Changes in dendritic spines structure and function play a critical role in a number of physiological processes, including synaptic transmission and plasticity, and are intimately linked to cognitive function. Alterations in dendritic spine morphogenesis occur in a number of neuropsychiatric disorders and likely underlie the cognitive and behavioral changes associated with these disorders. The neuronal guanine nucleotide exchange factor (GEF) kalirin is emerging as a key regulator of structural and functional plasticity at dendritic spines. Moreover, a series of recent studies have genetically and functionally linked kalirin signaling to several disorders, including schizophrenia and Alzheimer's disease. Kalirin signaling may thus represent a disease mechanism and provide a novel therapeutic target.
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Affiliation(s)
- Christine Remmers
- Department of Physiology, 303 E. Chicago Avenue, Chicago, IL 60611, USA
| | - Robert A Sweet
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; VISN 4 Mental Illness Research, Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Peter Penzes
- Department of Physiology, 303 E. Chicago Avenue, Chicago, IL 60611, USA; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
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32
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Ma XM, Miller MB, Vishwanatha KS, Gross MJ, Wang Y, Abbott T, Lam TT, Mains RE, Eipper BA. Nonenzymatic domains of Kalirin7 contribute to spine morphogenesis through interactions with phosphoinositides and Abl. Mol Biol Cell 2014; 25:1458-71. [PMID: 24600045 PMCID: PMC4004595 DOI: 10.1091/mbc.e13-04-0215] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Like several Rho GDP/GTP exchange factors (GEFs), Kalirin7 (Kal7) contains an N-terminal Sec14 domain and multiple spectrin repeats. A natural splice variant of Kalrn lacking the Sec14 domain and four spectrin repeats is unable to increase spine formation; our goal was to understand the function of the Sec14 and spectrin repeat domains. Kal7 lacking its Sec14 domain still increased spine formation, but the spines were short. Strikingly, Kal7 truncation mutants containing only the Sec14 domain and several spectrin repeats increased spine formation. The Sec14 domain bound phosphoinositides, a minor but crucial component of cellular membranes, and binding was increased by a phosphomimetic mutation. Expression of KalSec14-GFP in nonneuronal cells impaired receptor-mediated endocytosis, linking Kal7 to membrane trafficking. Consistent with genetic studies placing Abl, a non-receptor tyrosine kinase, and the Drosophila orthologue of Kalrn into the same signaling pathway, Abl1 phosphorylated two sites in the fourth spectrin repeat of Kalirin, increasing its sensitivity to calpain-mediated degradation. Treating cortical neurons of the wild-type mouse, but not the Kal7(KO) mouse, with an Abl inhibitor caused an increase in linear spine density. Phosphorylation of multiple sites in the N-terminal Sec14/spectrin region of Kal7 may allow coordination of the many signaling pathways contributing to spine morphogenesis.
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Affiliation(s)
- Xin-Ming Ma
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030 WM Keck Foundation Biotechnology Resource Laboratory, Yale/NIDA Neuroproteomics Center, Yale University, New Haven, CT 06511
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33
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Yam PT, Pincus Z, Gupta GD, Bashkurov M, Charron F, Pelletier L, Colman DR. N-cadherin relocalizes from the periphery to the center of the synapse after transient synaptic stimulation in hippocampal neurons. PLoS One 2013; 8:e79679. [PMID: 24223993 PMCID: PMC3815108 DOI: 10.1371/journal.pone.0079679] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/23/2013] [Indexed: 11/19/2022] Open
Abstract
N-cadherin is a cell adhesion molecule which is enriched at synapses. Binding of N-cadherin molecules to each other across the synaptic cleft has been postulated to stabilize adhesion between the presynaptic bouton and the postsynaptic terminal. N-cadherin is also required for activity-induced changes at synapses, including hippocampal long term potentiation and activity-induced spine expansion and stabilization. We hypothesized that these activity-dependent changes might involve changes in N-cadherin localization within synapses. To determine whether synaptic activity changes the localization of N-cadherin, we used structured illumination microscopy, a super-resolution approach which overcomes the conventional resolution limits of light microscopy, to visualize the localization of N-cadherin within synapses of hippocampal neurons. We found that synaptic N-cadherin exhibits a spectrum of localization patterns, ranging from puncta at the periphery of the synapse adjacent to the active zone to an even distribution along the synaptic cleft. Furthermore, the N-cadherin localization pattern within synapses changes during KCl depolarization and after transient synaptic stimulation. During KCl depolarization, N-cadherin relocalizes away from the central region of the synaptic cleft to the periphery of the synapse. In contrast, after transient synaptic stimulation with KCl followed by a period of rest in normal media, fewer synapses have N-cadherin present as puncta at the periphery and more synapses have N-cadherin present more centrally and uniformly along the synapse compared to unstimulated cells. This indicates that transient synaptic stimulation modulates N-cadherin localization within the synapse. These results bring new information to the structural organization and activity-induced changes occurring at synapses, and suggest that N-cadherin relocalization may contribute to activity dependent changes at synapses.
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Affiliation(s)
- Patricia T. Yam
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
- * E-mail:
| | - Zachary Pincus
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Gagan D. Gupta
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Mikhail Bashkurov
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Frédéric Charron
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
- Molecular Biology of Neural Development, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, Department of Biology, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Laurence Pelletier
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - David R. Colman
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
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Nectin-3 links CRHR1 signaling to stress-induced memory deficits and spine loss. Nat Neurosci 2013; 16:706-13. [DOI: 10.1038/nn.3395] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/09/2013] [Indexed: 12/12/2022]
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Tsai YC, Riess O, Soehn AS, Nguyen HP. The Guanine nucleotide exchange factor kalirin-7 is a novel synphilin-1 interacting protein and modifies synphilin-1 aggregate transport and formation. PLoS One 2012; 7:e51999. [PMID: 23284848 PMCID: PMC3527391 DOI: 10.1371/journal.pone.0051999] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/09/2012] [Indexed: 11/19/2022] Open
Abstract
Synphilin-1 has been identified as an interaction partner of α-synuclein, a key protein in the pathogenesis of Parkinson disease (PD). To further explore novel binding partners of synphilin-1, a yeast two hybrid screening was performed and kalirin-7 was identified as a novel interactor. We then investigated the effect of kalirin-7 on synphilin-1 aggregate formation. Coexpression of kalirin-7 and synphilin-1 caused a dramatic relocation of synphilin-1 cytoplasmic small inclusions to a single prominent, perinuclear inclusion. These perinuclear inclusions were characterized as being aggresomes according to their colocalization with microtubule organization center markers, and their formation was microtubule-dependent. Furthermore, kalirin-7 increased the susceptibility of synphilin-1 inclusions to be degraded as demonstrated by live cell imaging and quantification of aggregates. However, the kalirin-7-mediated synphilin-1 aggresome response was not dependent on the GEF activity of kalirin-7 since various dominant negative small GTPases could not inhibit the formation of aggresomes. Interestingly, the aggresome response was blocked by HDAC6 catalytic mutants and the HDAC inhibitor trichostatin A (TSA). Moreover, kalirin-7 decreased the level of acetylated α-tubulin in response to TSA, which suggests an effect of kalirin-7 on HDAC6-mediated protein transportation and aggresome formation. In summary, this is the first report demonstrating that kalirin-7 leads to the recruitment of synphilin-1 into aggresomes in a HDAC6-dependent manner and also links kalirin-7 to microtubule dynamics.
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Affiliation(s)
- Yu-Chun Tsai
- Department of Medical Genetics, University of Tuebingen, Tuebingen, Germany
| | - Olaf Riess
- Department of Medical Genetics, University of Tuebingen, Tuebingen, Germany
| | - Anne S. Soehn
- Department of Medical Genetics, University of Tuebingen, Tuebingen, Germany
| | - Huu Phuc Nguyen
- Department of Medical Genetics, University of Tuebingen, Tuebingen, Germany
- * E-mail:
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Cheadle L, Biederer T. The novel synaptogenic protein Farp1 links postsynaptic cytoskeletal dynamics and transsynaptic organization. ACTA ACUST UNITED AC 2012; 199:985-1001. [PMID: 23209303 PMCID: PMC3518221 DOI: 10.1083/jcb.201205041] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Synaptic adhesion organizes synapses, yet the signaling pathways that drive and integrate synapse development remain incompletely understood. We screened for regulators of these processes by proteomically analyzing synaptic membranes lacking the synaptogenic adhesion molecule SynCAM 1. This identified FERM, Rho/ArhGEF, and Pleckstrin domain protein 1 (Farp1) as strongly reduced in SynCAM 1 knockout mice. Farp1 regulates dendritic filopodial dynamics in immature neurons, indicating roles in synapse formation. Later in development, Farp1 is postsynaptic and its 4.1 protein/ezrin/radixin/moesin (FERM) domain binds SynCAM 1, assembling a synaptic complex. Farp1 increases synapse number and modulates spine morphology, and SynCAM 1 requires Farp1 for promoting spines. In turn, SynCAM 1 loss reduces the ability of Farp1 to elevate spine density. Mechanistically, Farp1 activates the GTPase Rac1 in spines downstream of SynCAM 1 clustering, and promotes F-actin assembly. Farp1 furthermore triggers a retrograde signal regulating active zone composition via SynCAM 1. These results reveal a postsynaptic signaling pathway that engages transsynaptic interactions to coordinate synapse development.
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Affiliation(s)
- Lucas Cheadle
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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Mandela P, Yankova M, Conti LH, Ma XM, Grady J, Eipper BA, Mains RE. Kalrn plays key roles within and outside of the nervous system. BMC Neurosci 2012; 13:136. [PMID: 23116210 PMCID: PMC3541206 DOI: 10.1186/1471-2202-13-136] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 10/22/2012] [Indexed: 11/23/2022] Open
Abstract
Background The human KALRN gene, which encodes a complex, multifunctional Rho GDP/GTP exchange factor, has been linked to cardiovascular disease, psychiatric disorders and neurodegeneration. Examination of existing Kalrn knockout mouse models has focused only on neuronal phenotypes. However, Kalirin was first identified through its interaction with an enzyme involved in the synthesis and secretion of multiple bioactive peptides, and studies in C.elegans revealed roles for its orthologue in neurosecretion. Results We used a broad array of tests to evaluate the effects of ablating a single exon in the spectrin repeat region of Kalrn (KalSRKO/KO); transcripts encoding Kalrn isoforms containing only the second GEF domain can still be produced from the single remaining functional Kalrn promoter. As expected, KalSRKO/KO mice showed a decrease in anxiety-like behavior and a passive avoidance deficit. No changes were observed in prepulse inhibition of acoustic startle or tests of depression-like behavior. Growth rate, parturition and pituitary secretion of growth hormone and prolactin were deficient in the KalSRKO/KO mice. Based on the fact that a subset of Kalrn isoforms is expressed in mouse skeletal muscle and the observation that muscle function in C.elegans requires its Kalrn orthologue, KalSRKO/KO mice were evaluated in the rotarod and wire hang tests. KalSRKO/KO mice showed a profound decrease in neuromuscular function, with deficits apparent in KalSR+/KO mice; these deficits were not as marked when loss of Kalrn expression was restricted to the nervous system. Pre- and postsynaptic deficits in the neuromuscular junction were observed, along with alterations in sarcomere length. Conclusions Many of the widespread and diverse deficits observed both within and outside of the nervous system when expression of Kalrn is eliminated may reflect its role in secretory granule function and its expression outside of the nervous system.
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Affiliation(s)
- Prashant Mandela
- Department of Neuroscience, University of Connecticut Health Science Center, Farmington, CT 06030-3401, USA
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Srivastava DP, Copits BA, Xie Z, Huda R, Jones KA, Mukherji S, Cahill ME, VanLeeuwen JE, Woolfrey KM, Rafalovich I, Swanson GT, Penzes P. Afadin is required for maintenance of dendritic structure and excitatory tone. J Biol Chem 2012; 287:35964-74. [PMID: 22948147 PMCID: PMC3476264 DOI: 10.1074/jbc.m112.363358] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 08/14/2012] [Indexed: 11/06/2022] Open
Abstract
The dendritic field of a neuron, which is determined by both dendritic architecture and synaptic strength, defines the synaptic input of a cell. Once established, a neuron's dendritic field is thought to remain relatively stable throughout a cell's lifetime. Perturbations in a dendritic structure or excitatory tone of a cell and thus its dendritic field are cellular alterations thought to be correlated with a number of psychiatric disorders. Although several proteins are known to regulate the development of dendritic arborization, much less is known about the mechanisms that maintain dendritic morphology and synaptic strength. In this study, we find that afadin, a component of N-cadherin·β-catenin·α-N-catenin adhesion complexes, is required for the maintenance of established dendritic arborization and synapse number. We further demonstrate that afadin directly interacts with AMPA receptors and that loss of this protein reduces the surface expression of GluA1- and GluA2-AMPA receptor subunits. Collectively, these data suggest that afadin is required for the maintenance of dendritic structure and excitatory tone.
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Affiliation(s)
- Deepak P. Srivastava
- From the Departments of Physiology
- the Department of Neuroscience and Centre for the Cellular Basis of Behaviour, James Black Centre, Institute of Psychiatry, King's College London, London SE5 9NU, United Kingdom
| | | | | | | | | | - Srishti Mukherji
- the Department of Neuroscience and Centre for the Cellular Basis of Behaviour, James Black Centre, Institute of Psychiatry, King's College London, London SE5 9NU, United Kingdom
| | | | | | | | | | | | - Peter Penzes
- From the Departments of Physiology
- Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and
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Vanleeuwen JE, Penzes P. Long-term perturbation of spine plasticity results in distinct impairments of cognitive function. J Neurochem 2012; 123:781-9. [PMID: 22862288 DOI: 10.1111/j.1471-4159.2012.07899.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/09/2012] [Accepted: 07/09/2012] [Indexed: 11/29/2022]
Abstract
Dendritic spines serve as the post-synaptic structural component of synapses. The structure and function of dendritic spines are dynamically regulated by a number of signaling pathways and allow for normal neural processing, whereas aberrant spine changes are thought to contribute to cognitive impairment in neuropsychiatric and neurodegenerative disorders. However, spine changes within different brain regions and their contribution to specific cognitive functions, especially later in adulthood, is not well understood. In this study, we used late-adult KALRN-deficient mice as a tool to investigate the vulnerability of different cognitive functions to long-term perturbations in spine plasticity in different forebrain regions. We found that in these mice, loss of one or both copies of KALRN lead to genotype and brain region-dependent reductions in spine density. Surprisingly, heterozygote and knockout mice showed differential impairments in cognitive phenotypes, including working memory, social recognition, and social approach. Correlation analysis between the site and magnitude of spine loss and behavioral alterations suggests that the interplay between brain regions is critical for complex cognitive processing and underscores the importance of spine plasticity in normal cognitive function. Long-term perturbation of spine plasticity results in distinct impairments of cognitive function. Using genetically modified mice deficient in a central regulator of spine plasticity, we investigated the brain region-specific contribution of spine numbers to various cognitive functions. We found distinct cognitive functions display differential sensitivity to spine loss in the cortex and hippocampus. Our data support spines as neuronal structures important for cognition and suggest interplay between brain regions is critical for complex cognitive processing.
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Affiliation(s)
- Jon-Eric Vanleeuwen
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Soria Fregozo C, Pérez Vega M. Actin-binding proteins and signalling pathways associated with the formation and maintenance of dendritic spines. NEUROLOGÍA (ENGLISH EDITION) 2012. [DOI: 10.1016/j.nrleng.2011.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Velázquez-Zamora DA, González-Tapia D, González-Ramírez MM, Flores-Soto ME, Vázquez-Valls E, Cervantes M, González-Burgos I. Plastic changes in dendritic spines of hippocampal CA1 pyramidal neurons from ovariectomized rats after estradiol treatment. Brain Res 2012; 1470:1-10. [PMID: 22750586 DOI: 10.1016/j.brainres.2012.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 05/02/2012] [Accepted: 06/06/2012] [Indexed: 02/05/2023]
Abstract
Cognitive impairment or its recovery has been associated with the absence or reestablishment of estrogenic actions in the central nervous system of female experimental animals or women. It has been proposed that these cognitive phenomena are related to estrogen-mediated modulatory activity of synaptic transmission in brain structures involved in cognitive functions. In the present work a morphological study was conducted in adult female ovariectomized rats to evaluate estradiol-dependent dendritic spine sprouting in hippocampal pyramidal neurons, and changes in the presynaptic marker synaptophysin. Three or ten days after estradiol treatment (10 μg/day, twice) in the ovariectomized rats, a significant increase of synaptophysin was observed, which was coincident with a significant higher numerical density of thin (22%), stubby (36%), mushroom (47%) and double spines (125%), at day 3, without significant changes of spine density at day 10, after treatment. These results may be interpreted as evidence of pre- and postsynaptic plastic events that may be involved in the modulation of cognitive-related behavioral performance after estrogen replacement therapy.
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Gonzalez-Billault C, Muñoz-Llancao P, Henriquez DR, Wojnacki J, Conde C, Caceres A. The role of small GTPases in neuronal morphogenesis and polarity. Cytoskeleton (Hoboken) 2012; 69:464-85. [PMID: 22605667 DOI: 10.1002/cm.21034] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 12/21/2022]
Abstract
The highly dynamic remodeling and cross talk of the microtubule and actin cytoskeleton support neuronal morphogenesis. Small RhoGTPases family members have emerged as crucial regulators of cytoskeletal dynamics. In this review we will comprehensively analyze findings that support the participation of RhoA, Rac, Cdc42, and TC10 in different neuronal morphogenetic events ranging from migration to synaptic plasticity. We will specifically address the contribution of these GTPases to support neuronal polarity and axonal elongation.
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Affiliation(s)
- Christian Gonzalez-Billault
- Faculty of Sciences, Laboratory of Cell and Neuronal Dynamics, Department of Biology and Institute for Cell Dynamics and Biotechnology, Universidad de Chile, Santiago, Chile.
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Rubio MD, Haroutunian V, Meador-Woodruff JH. Abnormalities of the Duo/Ras-related C3 botulinum toxin substrate 1/p21-activated kinase 1 pathway drive myosin light chain phosphorylation in frontal cortex in schizophrenia. Biol Psychiatry 2012; 71:906-14. [PMID: 22458949 PMCID: PMC3334466 DOI: 10.1016/j.biopsych.2012.02.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 02/07/2012] [Accepted: 02/09/2012] [Indexed: 12/18/2022]
Abstract
BACKGROUND Recent studies on GTPases have suggested that reduced Duo and cell division cycle 42 (Cdc42) transcript expression is involved in dendritic spine loss in schizophrenia. In murine models, Duo and Cdc42 phosphorylate p21-activated kinase 1 (PAK1), which modifies the activity of regulatory myosin light chain (MLC) and cofilin by altering their phosphorylation. Therefore, we hypothesized that in schizophrenia abnormal Duo and Cdc42 expression result in changes in MLC and/or cofilin phosphorylation, which might alter actin cytoskeleton dynamics underlying dendritic spine maintenance. METHODS We performed Western blot protein expression analysis in postmortem brains from patients diagnosed with schizophrenia and a comparison group. We focused our studies in the anterior cingulate cortex (ACC; n = 33 comparison group; n = 36 schizophrenia) and dorsolateral prefrontal cortex (DLPFC; n = 29 comparison group; n = 35 schizophrenia). RESULTS In both ACC and DLPFC, we found a reduction of Duo expression and PAK1 phosphorylation in schizophrenia. Cdc42 protein expression was decreased in ACC but not in DLPFC. In ACC, we observed decreased PAK1 phosphorylation and increased MLC phosphorylation (pMLC), whereas in DLPFC pMLC remained unchanged. CONCLUSIONS These data suggest a novel mechanism that might underlie dendritic spine loss in schizophrenia. The increase in pMLC seen in ACC might be associated with dendritic spine shrinkage. The lack of an effect on pMLC in DLPFC suggests that in schizophrenia PAK1 downstream pathways are differentially affected in these cortical areas.
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Affiliation(s)
- María D. Rubio
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, USA,Corresponding author: , Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, 1719 6th Ave. S., CIRC 590C, Birmingham, AL 35294-0021, USA
| | - Vahram Haroutunian
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, USA
| | - James H. Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Afadin, a Ras/Rap effector that controls cadherin function, promotes spine and excitatory synapse density in the hippocampus. J Neurosci 2012; 32:99-110. [PMID: 22219273 DOI: 10.1523/jneurosci.4565-11.2012] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Many molecules regulate synaptogenesis, but intracellular signaling pathways required for their functions are poorly understood. Afadin is a Rap-regulated, actin-binding protein that promotes cadherin complex assembly as well as binding many other cell adhesion molecules and receptors. To examine its role in mediating synaptogenesis, we deleted afadin (mllt1), using a conditional allele, in postmitotic hippocampal neurons. Consistent with its role in promoting cadherin recruitment, afadin deletion resulted in 70% fewer and less intense N-cadherin puncta with similar reductions of β-catenin and αN-catenin puncta densities and 35% reduction in EphB2 puncta density. Its absence also resulted in 40% decreases in spine and excitatory synapse densities in the stratum radiatum of CA1, as determined by morphology, apposition of presynaptic and postsynaptic markers, and synaptic transmission. The remaining synapses appeared to function normally. Thus, afadin is a key intracellular signaling molecule for cadherin recruitment and is necessary for spine and synapse formation in vivo.
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Gardoni F, Di Luca M, Malinverno M, Marcello E, Verpelli C, Sala C, Di Luca M. The neuropeptide PACAP38 induces dendritic spine remodeling through ADAM10/N-Cadherin signaling pathway. J Cell Sci 2012; 125:1401-6. [DOI: 10.1242/jcs.097576] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The neuropeptide pituitary adenylate cyclase-activating polypeptide 38 (PACAP38) has been implicated in the induction of synaptic plasticity at the excitatory glutamatergic synapse. In particular, recent studies have shown that it is involved in the regulation of NMDA and AMPA receptor activation. Here we demonstrate the effect of PACAP38 on the modulation of dendritic spine morphology through ADAM10/N-Cadherin/AMPA receptor signaling pathway. Treatment of primary hippocampal neurons with PACAP38 induces an accumulation of ADAM10 at the postsynaptic membrane. This event leads to a significant decrease of dendritic spine head width and to a concomitant reduction of GluR1 co-localization with postsynaptic markers. PACAP38-induced effect on dendritic spine head width is prevented by either treatment with ADAM10 specific inhibitor or transfection of a cleavage-defective N-Cadherin construct, mutated in the ADAM10 cleavage site. Overall, our findings reveal for the first time that PACAP38 is involved in the modulation of dendritic spine morphology in hippocampal neurons and assign to the ADAM10/N-Cadherin signaling pathway a crucial role in this modification of the excitatory glutamatergic synapse.
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Bukalo O, Dityatev A. Synaptic Cell Adhesion Molecules. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:97-128. [DOI: 10.1007/978-3-7091-0932-8_5] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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47
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Kalirin signaling: implications for synaptic pathology. Mol Neurobiol 2011; 45:109-18. [PMID: 22194219 DOI: 10.1007/s12035-011-8223-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 11/29/2011] [Indexed: 01/31/2023]
Abstract
Spine morphogenesis and plasticity are intimately linked to cognition, and there is strong evidence that aberrant regulation of spine plasticity is associated with physiological, behavioral, and pathological conditions. The neuronal guanine nucleotide exchange factor (GEF) kalirin is emerging as a key regulator of structural and functional plasticity at dendritic spines. Here, we review recent studies that have genetically and functionally linked kalirin signaling to a number of human disorders. Kalirin signaling may thus represent a disease mechanism and provide a novel therapeutic target.
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Lemtiri-Chlieh F, Zhao L, Kiraly DD, Eipper BA, Mains RE, Levine ES. Kalirin-7 is necessary for normal NMDA receptor-dependent synaptic plasticity. BMC Neurosci 2011; 12:126. [PMID: 22182308 PMCID: PMC3261125 DOI: 10.1186/1471-2202-12-126] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 12/19/2011] [Indexed: 01/18/2023] Open
Abstract
Background Dendritic spines represent the postsynaptic component of the vast majority of excitatory synapses present in the mammalian forebrain. The ability of spines to rapidly alter their shape, size, number and receptor content in response to stimulation is considered to be of paramount importance during the development of synaptic plasticity. Indeed, long-term potentiation (LTP), widely believed to be a cellular correlate of learning and memory, has been repeatedly shown to induce both spine enlargement and the formation of new dendritic spines. In our studies, we focus on Kalirin-7 (Kal7), a Rho GDP/GTP exchange factor (Rho-GEF) localized to the postsynaptic density that plays a crucial role in the development and maintenance of dendritic spines both in vitro and in vivo. Previous studies have shown that mice lacking Kal7 (Kal7KO) have decreased dendritic spine density in the hippocampus as well as focal hippocampal-dependent learning impairments. Results We have performed a detailed electrophysiological characterization of the role of Kal7 in hippocampal synaptic plasticity. We show that loss of Kal7 results in impaired NMDA receptor-dependent LTP and long-term depression, whereas a NMDA receptor-independent form of LTP is shown to be normal in the absence of Kal7. Conclusions These results indicate that Kal7 is an essential and selective modulator of NMDA receptor-dependent synaptic plasticity in the hippocampus.
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Affiliation(s)
- Fouad Lemtiri-Chlieh
- The King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
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Soria Fregozo C, Pérez Vega MI. Actin-binding proteins and signalling pathways associated with the formation and maintenance of dendritic spines. Neurologia 2011; 27:421-31. [PMID: 22178050 DOI: 10.1016/j.nrl.2011.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 10/09/2011] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Dendritic spines are the main sites of excitatory synaptic contacts. Moreover, they present plastic responses to different stimuli present in synaptic activity or damage, ranging from an increase or decrease in their total number, to redistribution of progenitor dendritic spines, to variations in their size or shape. However, the spines can remain stable for a long time. BACKGROUND The use of experimental models has shown that different molecules of the F-actin binding and signalling pathways are closely related to the development, maintenance and plasticity of excitatory synapses, which could affect the number, size and shape of the dendritic spines; these mechanisms affect and depend on the reorganisation of the actin cytoskeleton. DEVELOPMENT It is proposed that the filopodia are precursors of dendritic spines. Drebrin is an F-actin binding protein, and it is responsible for concentrating F-actin and PSD-95 in filopodia that will guide the formation of the new spines. CONCLUSION The specific mechanisms of actin regulation are an integral part in the formation, maturing process and plasticity of dendritic spines in association with the various actin cytoskeleton-binding proteins The signalling pathways mediated by small GTPases and the equilibrium between G-actin and F-actin are also involved.
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Affiliation(s)
- C Soria Fregozo
- Laboratorio de Psicobiología y Biología Molecular, Departamento de Ciencias de la Tierra y de la Vida, Centro Universitario de los Lagos, Universidad de Guadalajara, Guadalajara, Mexico.
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Kalirin binds the NR2B subunit of the NMDA receptor, altering its synaptic localization and function. J Neurosci 2011; 31:12554-65. [PMID: 21880917 DOI: 10.1523/jneurosci.3143-11.2011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ability of dendritic spines to change size and shape rapidly is critical in modulating synaptic strength; these morphological changes are dependent upon rearrangements of the actin cytoskeleton. Kalirin-7 (Kal7), a Rho guanine nucleotide exchange factor localized to the postsynaptic density (PSD), modulates dendritic spine morphology in vitro and in vivo. Kal7 activates Rac and interacts with several PSD proteins, including PSD-95, DISC-1, AF-6, and Arf6. Mice genetically lacking Kal7 (Kal7(KO)) exhibit deficient hippocampal long-term potentiation (LTP) as well as behavioral abnormalities in models of addiction and learning. Purified PSDs from Kal7(KO) mice contain diminished levels of NR2B, an NMDA receptor subunit that plays a critical role in LTP induction. Here we demonstrate that Kal7(KO) animals have decreased levels of NR2B-dependent NMDA receptor currents in cortical pyramidal neurons as well as a specific deficit in cell surface expression of NR2B. Additionally, we demonstrate that the genotypic differences in conditioned place preference and passive avoidance learning seen in Kal7(KO) mice are abrogated when animals are treated with an NR2B-specific antagonist during conditioning. Finally, we identify a stable interaction between the pleckstrin homology domain of Kal7 and the juxtamembrane region of NR2B preceding its cytosolic C-terminal domain. Binding of NR2B to a protein that modulates the actin cytoskeleton is important, as NMDA receptors require actin integrity for synaptic localization and function. These studies demonstrate a novel and functionally important interaction between the NR2B subunit of the NMDA receptor and Kalirin, proteins known to be essential for normal synaptic plasticity.
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