1
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Phosphoproteome profiling of hippocampal synaptic plasticity. Biochem Biophys Res Commun 2022; 626:92-99. [DOI: 10.1016/j.bbrc.2022.07.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/26/2022] [Accepted: 07/14/2022] [Indexed: 11/17/2022]
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2
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Arisawa T, Miyazaki T, Ota W, Sano A, Suyama K, Takada Y, Takahashi T. [ 11C]K-2 image with positron emission tomography represents cell surface AMPA receptors. Neurosci Res 2021; 173:106-113. [PMID: 34033829 DOI: 10.1016/j.neures.2021.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/29/2021] [Accepted: 05/20/2021] [Indexed: 11/27/2022]
Abstract
The glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) is an important molecule in neurotransmission. We have recently developed the first positron emission tomography (PET) tracer [11C]K-2 to visualize and quantify AMPARs in the living human brain. After injection, [11C]K-2 is hydrolyzed at the terminal amide (and is thus metabolized to a major metabolite, [11C]K-2OH) within 10 min, representing the PET image in rodents and humans. Here, we found that K-2OH did not penetrate the cell membrane but slowly passed through the blood brain barrier (BBB) with paracellular transport. Furthermore, major efflux transporters in the BBB did not carry K-2OH. Logan graphical analysis exhibited reversible binding kinetics of this radiotracer in healthy individuals; these results demonstrated that the PET image of this tracer represents cell surface AMPARs with passive penetration of [11C]K-2OH through the BBB, resulting in reversible binding kinetics. Thus, PET images with this tracer depict the physiologically crucial fraction of AMPARs.
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Affiliation(s)
- Tetsu Arisawa
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Tomoyuki Miyazaki
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Wataru Ota
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Akane Sano
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Kumiko Suyama
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Yuuki Takada
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan
| | - Takuya Takahashi
- Yokohama City University Graduate School of Medicine, Department of Physiology, Yokohama, 236-0004, Japan.
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3
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Thompson AP, Bitsina C, Gray JL, von Delft F, Brennan PE. RHO to the DOCK for GDP disembarking: Structural insights into the DOCK GTPase nucleotide exchange factors. J Biol Chem 2021; 296:100521. [PMID: 33684443 PMCID: PMC8063744 DOI: 10.1016/j.jbc.2021.100521] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 01/16/2023] Open
Abstract
The human dedicator of cytokinesis (DOCK) family consists of 11 structurally conserved proteins that serve as atypical RHO guanine nucleotide exchange factors (RHO GEFs). These regulatory proteins act as mediators in numerous cellular cascades that promote cytoskeletal remodeling, playing roles in various crucial processes such as differentiation, migration, polarization, and axon growth in neurons. At the molecular level, DOCK DHR2 domains facilitate nucleotide dissociation from small GTPases, a process that is otherwise too slow for rapid spatiotemporal control of cellular signaling. Here, we provide an overview of the biological and structural characteristics for the various DOCK proteins and describe how they differ from other RHO GEFs and between DOCK subfamilies. The expression of the family varies depending on cell or tissue type, and they are consequently implicated in a broad range of disease phenotypes, particularly in the brain. A growing body of available structural information reveals the mechanism by which the catalytic DHR2 domain elicits nucleotide dissociation and also indicates strategies for the discovery and design of high-affinity small-molecule inhibitors. Such compounds could serve as chemical probes to interrogate the cellular function and provide starting points for drug discovery of this important class of enzymes.
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Affiliation(s)
- Andrew P Thompson
- Nuffield Department of Medicine, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom
| | - Christina Bitsina
- Nuffield Department of Medicine, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom
| | - Janine L Gray
- Nuffield Department of Medicine, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom
| | - Frank von Delft
- Nuffield Department of Medicine, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom; Diamond Light Source, Harwell Science and Innovation Campus, Didcot, United Kingdom; Department of Biochemistry, University of Johannesburg, Auckland Park, South Africa
| | - Paul E Brennan
- Nuffield Department of Medicine, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, Centre for Medicines Discovery, University of Oxford, Oxford, United Kingdom.
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4
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Xu Y, Song X, Wang D, Wang Y, Li P, Li J. Proteomic insights into synaptic signaling in the brain: the past, present and future. Mol Brain 2021; 14:37. [PMID: 33596935 PMCID: PMC7888154 DOI: 10.1186/s13041-021-00750-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/09/2021] [Indexed: 12/29/2022] Open
Abstract
Chemical synapses in the brain connect neurons to form neural circuits, providing the structural and functional bases for neural communication. Disrupted synaptic signaling is closely related to a variety of neurological and psychiatric disorders. In the past two decades, proteomics has blossomed as a versatile tool in biological and biomedical research, rendering a wealth of information toward decoding the molecular machinery of life. There is enormous interest in employing proteomic approaches for the study of synapses, and substantial progress has been made. Here, we review the findings of proteomic studies of chemical synapses in the brain, with special attention paid to the key players in synaptic signaling, i.e., the synaptic protein complexes and their post-translational modifications. Looking toward the future, we discuss the technological advances in proteomics such as data-independent acquisition mass spectrometry (DIA-MS), cross-linking in combination with mass spectrometry (CXMS), and proximity proteomics, along with their potential to untangle the mystery of how the brain functions at the molecular level. Last but not least, we introduce the newly developed synaptomic methods. These methods and their successful applications marked the beginnings of the synaptomics era.
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Affiliation(s)
- Yalan Xu
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Xiuyue Song
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Dong Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Jing Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China.
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5
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Namekata K, Guo X, Kimura A, Azuchi Y, Kitamura Y, Harada C, Harada T. Roles of the DOCK-D family proteins in a mouse model of neuroinflammation. J Biol Chem 2020; 295:6710-6720. [PMID: 32241915 DOI: 10.1074/jbc.ra119.010438] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 03/16/2020] [Indexed: 02/01/2023] Open
Abstract
The DOCK-D (dedicator of cytokinesis D) family proteins are atypical guanine nucleotide exchange factors that regulate Rho GTPase activity. The family consists of Zizimin1 (DOCK9), Zizimin2 (DOCK11), and Zizimin3 (DOCK10). Functions of the DOCK-D family proteins are presently not well-explored, and the role of the DOCK-D family in neuroinflammation is unknown. In this study, we generated three mouse lines in which DOCK9 (DOCK9 -/-), DOCK10 (DOCK10 -/-), or DOCK11 (DOCK11 -/-) had been deleted and examined the phenotypic effects of these gene deletions in MOG35-55 peptide-induced experimental autoimmune encephalomyelitis, an animal model of the neuroinflammatory disorder multiple sclerosis. We found that all the gene knockout lines were healthy and viable. The only phenotype observed under normal conditions was a slightly smaller proportion of B cells in splenocytes in DOCK10 -/- mice than in the other mouse lines. We also found that the migration ability of macrophages is impaired in DOCK10 -/- and DOCK11 -/- mice and that the severity of experimental autoimmune encephalomyelitis was ameliorated only in DOCK10 -/- mice. No apparent phenotype was observed for DOCK9 -/- mice. Further investigations indicated that lipopolysaccharide stimulation up-regulates DOCK10 expression in microglia and that microglial migration is decreased in DOCK10 -/- mice. Up-regulation of C-C motif chemokine ligand 2 (CCL2) expression induced by activation of Toll-like receptor 4 or 9 signaling was reduced in DOCK10 -/- astrocytes compared with WT astrocytes. Taken together, our findings suggest that DOCK10 plays a role in innate immunity and neuroinflammation and might represent a potential therapeutic target for managing multiple sclerosis.
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Affiliation(s)
- Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yuriko Azuchi
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yuta Kitamura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
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6
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Kamalova A, Nakagawa T. AMPA receptor structure and auxiliary subunits. J Physiol 2020; 599:453-469. [PMID: 32004381 DOI: 10.1113/jp278701] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 11/08/2022] Open
Abstract
Fast excitatory synaptic transmission in the mammalian brain is largely mediated by AMPA-type ionotropic glutamate receptors (AMPARs), which are activated by the neurotransmitter glutamate. In synapses, the function of AMPARs is tuned by their auxiliary subunits, a diverse set of membrane proteins associated with the core pore-forming subunits of the AMPARs. Each auxiliary subunit provides distinct functional modulation of AMPARs, ranging from regulation of trafficking to shaping ion channel gating kinetics. Understanding the molecular mechanism of the function of these complexes is key to decoding synaptic modulation and their global roles in cognitive activities, such as learning and memory. Here, we review the structural and molecular complexity of AMPAR-auxiliary subunit complexes, as well as their functional diversity in different brain regions. We suggest that the recent structural information provides new insights into the molecular mechanisms underlying synaptic functions of AMPAR-auxiliary subunit complexes.
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Affiliation(s)
- Aichurok Kamalova
- Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, Nashville, TN, 37232, USA.,Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN, 37232, USA
| | - Terunaga Nakagawa
- Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, Nashville, TN, 37232, USA.,Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN, 37232, USA.,Center for Structural Biology, Vanderbilt University, School of Medicine, Nashville, TN, 37232, USA
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7
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Midorikawa R, Takakura D, Morise J, Wakazono Y, Kawasaki N, Oka S, Takamiya K. Monitoring the glycosylation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate-type glutamate receptors using specific antibodies reveals a novel regulatory mechanism of N-glycosylation occupancy by molecular chaperones in mice. J Neurochem 2020; 153:567-585. [PMID: 31958346 DOI: 10.1111/jnc.14964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/11/2020] [Accepted: 01/13/2020] [Indexed: 01/11/2023]
Abstract
In the mammalian nervous system, protein N-glycosylation plays an important role in neuronal physiology. In this study, we performed a comprehensive N-glycosylation analysis of mouse GluA1, one of the major subunits of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate type glutamate receptor, which possesses six potential N-glycosylation sites in the N-terminal domain. By mass spectrometry-based analysis, we identified the N-glycoforms and semiquantitatively determined the site-specific N-glycosylation occupancy of GluA1. In addition, only the N401-glycosylation site demonstrated incomplete N-glycosylation occupancy. Therefore, we generated a peptide antibody that specifically detects the N401-glycan-free form to precisely quantify N401-glycosylation occupancy. Using this antibody, we clarified that N401 occupancy varies between cell types and increases in an age-dependent manner in mouse forebrains. To address the regulatory mechanism of N401-glycosylation, binding proteins of GluA1 around the N401 site were screened. HSP70 family proteins, including Bip, were identified as candidates. Bip has been known as a molecular chaperone that plays a key role in protein folding in the ER (endoplasmic reticulum). To examine the involvement of Bip in N401-glycosylation, the effect of Bip over-expression on N401 occupancy was evaluated in HEK293T cells, and the results demonstrated Bip increases the N401 glycan-free form by mediating selective prolongation of its protein half-life. Taken together, we propose that the N401-glycosite of GluA1 receives a unique control of modification, and we also propose a novel N-glycosylation occupancy regulatory mechanism by Bip that might be associated with α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptors function in the brain.
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Affiliation(s)
- Ryosuke Midorikawa
- Department of Neuroscience, University of Miyazaki Faculty of Medicine, Miyazaki, Japan
| | - Daisuke Takakura
- Project for Utilizing Glycans in the Development of Innovative Drug Discovery Technologies, Shinanomachi Research Park, Keio University School of Medicine, Tokyo, Japan
| | - Jyoji Morise
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshihiko Wakazono
- Department of Neuroscience, University of Miyazaki Faculty of Medicine, Miyazaki, Japan
| | - Nana Kawasaki
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | - Shogo Oka
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kogo Takamiya
- Department of Neuroscience, University of Miyazaki Faculty of Medicine, Miyazaki, Japan
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8
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LARGE, an intellectual disability-associated protein, regulates AMPA-type glutamate receptor trafficking and memory. Proc Natl Acad Sci U S A 2018; 115:7111-7116. [PMID: 29915039 DOI: 10.1073/pnas.1805060115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in the human LARGE gene result in severe intellectual disability and muscular dystrophy. How LARGE mutation leads to intellectual disability, however, is unclear. In our proteomic study, LARGE was found to be a component of the AMPA-type glutamate receptor (AMPA-R) protein complex, a main player for learning and memory in the brain. Here, our functional study of LARGE showed that LARGE at the Golgi apparatus (Golgi) negatively controlled AMPA-R trafficking from the Golgi to the plasma membrane, leading to down-regulated surface and synaptic AMPA-R targeting. In LARGE knockdown mice, long-term potentiation (LTP) was occluded by synaptic AMPA-R overloading, resulting in impaired contextual fear memory. These findings indicate that the fine-tuning of AMPA-R trafficking by LARGE at the Golgi is critical for hippocampus-dependent memory in the brain. Our study thus provides insights into the pathophysiology underlying cognitive deficits in brain disorders associated with intellectual disability.
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9
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Neuronal calcium channel α1 subunit interacts with AMPA receptor, increasing its cell surface localisation. Biochem Biophys Res Commun 2018; 498:402-408. [DOI: 10.1016/j.bbrc.2018.02.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/11/2018] [Indexed: 02/07/2023]
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10
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Jones EV, Bernardinelli Y, Zarruk JG, Chierzi S, Murai KK. SPARC and GluA1-Containing AMPA Receptors Promote Neuronal Health Following CNS Injury. Front Cell Neurosci 2018; 12:22. [PMID: 29449802 PMCID: PMC5799273 DOI: 10.3389/fncel.2018.00022] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/15/2018] [Indexed: 12/22/2022] Open
Abstract
The proper formation and maintenance of functional synapses in the central nervous system (CNS) requires communication between neurons and astrocytes and the ability of astrocytes to release neuromodulatory molecules. Previously, we described a novel role for the astrocyte-secreted matricellular protein SPARC (Secreted Protein, Acidic and Rich in Cysteine) in regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and plasticity at developing synapses. SPARC is highly expressed by astrocytes and microglia during CNS development but its level is reduced in adulthood. Interestingly, SPARC has been shown to be upregulated in CNS injury and disease. However, the role of SPARC upregulation in these contexts is not fully understood. In this study, we investigated the effect of chronic SPARC administration on glutamate receptors on mature hippocampal neuron cultures and following CNS injury. We found that SPARC treatment increased the number of GluA1-containing AMPARs at synapses and enhanced synaptic function. Furthermore, we determined that the increase in synaptic strength induced by SPARC could be inhibited by Philanthotoxin-433, a blocker of homomeric GluA1-containing AMPARs. We then investigated the effect of SPARC treatment on neuronal health in an injury context where SPARC expression is upregulated. We found that SPARC levels are increased in astrocytes and microglia following middle cerebral artery occlusion (MCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro. Remarkably, chronic pre-treatment with SPARC prevented OGD-induced loss of synaptic GluA1. Furthermore, SPARC treatment reduced neuronal death through Philanthotoxin-433 sensitive GluA1 receptors. Taken together, this study suggests a novel role for SPARC and GluA1 in promoting neuronal health and recovery following CNS damage.
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Affiliation(s)
- Emma V Jones
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | | | - Juan G Zarruk
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Sabrina Chierzi
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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11
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Differential Regulation of Evoked and Spontaneous Release by Presynaptic NMDA Receptors. Neuron 2017; 96:839-855.e5. [DOI: 10.1016/j.neuron.2017.09.030] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/03/2017] [Accepted: 09/19/2017] [Indexed: 01/04/2023]
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12
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Du Z, Tertrais M, Courtand G, Leste-Lasserre T, Cardoit L, Masmejean F, Halgand C, Cho YH, Garret M. Differential Alteration in Expression of Striatal GABA AR Subunits in Mouse Models of Huntington's Disease. Front Mol Neurosci 2017; 10:198. [PMID: 28676743 PMCID: PMC5476702 DOI: 10.3389/fnmol.2017.00198] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/06/2017] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is a neurodegenerative disorder characterized by progressive motor symptoms that are preceded by cognitive deficits and is considered as a disorder that primarily affects forebrain striatal neurons. To gain a better understanding of the molecular and cellular mechanisms associated with disease progression, we analyzed the expression of proteins involved in GABAergic neurotransmission in the striatum of the R6/1 transgenic mouse model. Western blot, quantitative PCR and immunohistochemical analyses were conducted on male R6/1 mice and age-matched wild type littermates. Analyses were performed on 2 and 6 month-old animals, respectively, before and after the onset of motor symptoms. Expression of GAD 67, GAD 65, NL2, or gephyrin proteins, involved in GABA synthesis or synapse formation did not display major changes. In contrast, expression of α1, α3 and α5 GABAAR subunits was increased while the expression of δ was decreased, suggesting a change in tonic- and phasic inhibitory transmission. Western blot analysis of the striatum from 8 month-old Hdh Q111, a knock-in mouse model of HD with mild deficits, confirmed the α1 subunit increased expression. From immunohistochemical analyses, we also found that α1 subunit expression is increased in medium-sized spiny projection neurons (MSN) and decreased in parvalbumin (PV)-expressing interneurons at 2 and 6 months in R6/1 mice. Moreover, α2 subunit labeling on the PV and MSN cell membranes was increased at 2 months and decreased at 6 months. Alteration of gene expression in the striatum and modification of GABAA receptor subtypes in both interneurons and projection neurons suggested that HD mutation has a profound effect on synaptic plasticity at an early stage, before the onset of motor symptoms. These results also indicate that cognitive and other behavioral deficits may be associated with changes in GABAergic neurotransmission that consequently could be a relevant target for early therapeutic treatment.
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Affiliation(s)
- Zhuowei Du
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Margot Tertrais
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Gilles Courtand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Thierry Leste-Lasserre
- Institut National de la Santé et de la Recherche Médicale, Neurocentre Magendie, U862, Physiopathologie de la Plasticité NeuronaleBordeaux, France.,Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, University of BordeauxBordeaux, France
| | - Laura Cardoit
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Frédérique Masmejean
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Christophe Halgand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Yoon H Cho
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Maurice Garret
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
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13
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Baucum AJ. Proteomic Analysis of Postsynaptic Protein Complexes Underlying Neuronal Plasticity. ACS Chem Neurosci 2017; 8:689-701. [PMID: 28211672 DOI: 10.1021/acschemneuro.7b00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Normal neuronal communication and synaptic plasticity at glutamatergic synapses requires dynamic regulation of postsynaptic molecules. Protein expression and protein post-translational modifications regulate protein interactions that underlie this organization. In this Review, we highlight data obtained over the last 20 years that have used qualitative and quantitative proteomics-based approaches to identify postsynaptic protein complexes. Herein, we describe how these proteomics studies have helped lay the foundation for understanding synaptic physiology and perturbations in synaptic signaling observed in different pathologies. We also describe emerging technologies that can be useful in these analyses. We focus on protein complexes associated with the highly abundant and functionally critical proteins: calcium/calmodulin-dependent protein kinase II, the N-methyl-d-aspartate, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors, and postsynaptic density protein of 95 kDa.
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Affiliation(s)
- Anthony J. Baucum
- Department of Biology, Stark Neurosciences
Research Institute, Indiana University-Purdue University Indianapolis, 723 W. Michigan St., Indianapolis, Indiana 46202, United States
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14
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Wills TA, Baucum AJ, Louderback KM, Chen Y, Pasek JG, Delpire E, Tabb DL, Colbran RJ, Winder DG. Chronic intermittent alcohol disrupts the GluN2B-associated proteome and specifically regulates group I mGlu receptor-dependent long-term depression. Addict Biol 2017; 22:275-290. [PMID: 26549202 PMCID: PMC4860359 DOI: 10.1111/adb.12319] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/31/2015] [Accepted: 09/11/2015] [Indexed: 02/03/2023]
Abstract
N-Methyl-d-aspartate receptors (NMDARs) are major targets of both acute and chronic alcohol, as well as regulators of plasticity in a number of brain regions. Aberrant plasticity may contribute to the treatment resistance and high relapse rates observed in alcoholics. Recent work suggests that chronic alcohol treatment preferentially modulates both the expression and subcellular localization of NMDARs containing the GluN2B subunit. Signaling through synaptic and extrasynaptic GluN2B-NMDARs has already been implicated in the pathophysiology of various other neurological disorders. NMDARs interact with a large number of proteins at the glutamate synapse, and a better understanding of how alcohol modulates this proteome is needed. We employed a discovery-based proteomic approach in subcellular fractions of hippocampal tissue from chronic intermittent alcohol (CIE)-exposed C57Bl/6J mice to gain insight into alcohol-induced changes in GluN2B signaling complexes. Protein enrichment analyses revealed changes in the association of post-synaptic proteins, including scaffolding, glutamate receptor and PDZ-domain binding proteins with GluN2B. In particular, GluN2B interaction with metabotropic glutamate (mGlu)1/5 receptor-dependent long-term depression (LTD)-associated proteins such as Arc and Homer 1 was increased, while GluA2 was decreased. Accordingly, we found a lack of mGlu1/5 -induced LTD while α1 -adrenergic receptor-induced LTD remained intact in hippocampal CA1 following CIE. These data suggest that CIE specifically disrupts mGlu1/5 -LTD, representing a possible connection between NMDAR and mGlu receptor signaling. These studies not only demonstrate a new way in which alcohol can modulate plasticity in the hippocampus but also emphasize the utility of this discovery-based proteomic approach to generate new hypotheses regarding alcohol-related mechanisms.
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Affiliation(s)
- Tiffany A. Wills
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Anthony J. Baucum
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202
| | | | - Yaoyi Chen
- Department of Biochemical Informatics, Vanderbilt University School of Medicine, Nashville TN 37232
| | - Johanna G. Pasek
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232
| | - Eric Delpire
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville TN 37232
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville TN 37232
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville TN 37232
| | - David L. Tabb
- Department of Biochemical Informatics, Vanderbilt University School of Medicine, Nashville TN 37232
| | - Roger J. Colbran
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville TN 37232
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville TN 37232
| | - Danny G. Winder
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville TN 37232
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville TN 37232
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15
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Subunit-specific synaptic delivery of AMPA receptors by auxiliary chaperone proteins TARPγ8 and GSG1L in classical conditioning. Neurosci Lett 2017; 645:53-59. [PMID: 28219790 DOI: 10.1016/j.neulet.2017.02.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 02/03/2017] [Accepted: 02/15/2017] [Indexed: 12/23/2022]
Abstract
AMPA receptor (AMPAR) trafficking has emerged as a fundamental concept for understanding mechanisms of learning and memory as well as many neurological disorders. Classical conditioning is a simple and highly conserved form of associative learning. Our studies use an ex vivo brainstem preparation in which to study cellular mechanisms underlying learning during a neural correlate of eyeblink conditioning. Two stages of AMPAR synaptic delivery underlie conditioning utilizing sequential trafficking of GluA1-containing AMPARs early in conditioning followed by replacement with GluA4 subunits later. Subunit-selective trafficking of AMPARs is poorly understood. Here, we focused on identification of auxiliary chaperone proteins that traffic AMPARs. The results show that auxiliary proteins TARPγ8 and GSG1L are colocalized with AMPARs on abducens motor neurons that generate the conditioning. Significantly, TARPγ8 was observed to chaperone GluA1-containing AMPARs during synaptic delivery early in conditioning while GSG1L chaperones GluA4 subunits later in conditioning. Interestingly, TARPγ8 remains at the membrane surface as GluA1 subunits are withdrawn and associates with GluA4 when they are delivered to synapses. These data indicate that GluA1- and GluA4-containing AMPARs are selectively chaperoned by TARPγ8 and GSG1L, respectively. Therefore, sequential subunit-selective trafficking of AMPARs during conditioning is achieved through the timing of their interactions with specific auxiliary proteins.
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16
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SALM4 suppresses excitatory synapse development by cis-inhibiting trans-synaptic SALM3-LAR adhesion. Nat Commun 2016; 7:12328. [PMID: 27480238 PMCID: PMC4974644 DOI: 10.1038/ncomms12328] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 06/23/2016] [Indexed: 12/01/2022] Open
Abstract
Synaptic adhesion molecules regulate various aspects of synapse development, function and plasticity. These functions mainly involve trans-synaptic interactions and positive regulations, whereas cis-interactions and negative regulation are less understood. Here we report that SALM4, a member of the SALM/Lrfn family of synaptic adhesion molecules, suppresses excitatory synapse development through cis inhibition of SALM3, another SALM family protein with synaptogenic activity. Salm4-mutant (Salm4−/−) mice show increased excitatory synapse numbers in the hippocampus. SALM4 cis-interacts with SALM3, inhibits trans-synaptic SALM3 interaction with presynaptic LAR family receptor tyrosine phosphatases and suppresses SALM3-dependent presynaptic differentiation. Importantly, deletion of Salm3 in Salm4−/− mice (Salm3−/−; Salm4−/−) normalizes the increased excitatory synapse number. These results suggest that SALM4 negatively regulates excitatory synapses via cis inhibition of the trans-synaptic SALM3–LAR adhesion. Synaptic adhesion molecules regulate synapse development and function by both cis and trans-interactions. Here, Lie et al. show that postsynaptic SALM4 regulates excitatory synapse numbers by cis inhibition of the SALM3-LAR transynaptic interaction.
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17
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Regulation of AMPA receptor subunit GluA1 surface expression by PAK3 phosphorylation. Proc Natl Acad Sci U S A 2015; 112:E5883-90. [PMID: 26460013 DOI: 10.1073/pnas.1518382112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
AMPA receptors (AMPARs) are the major excitatory receptors of the brain and are fundamental to synaptic plasticity, memory, and cognition. Dynamic recycling of AMPARs in neurons is regulated through several types of posttranslational modification, including phosphorylation. Here, we identify a previously unidentified signal transduction cascade that modulates phosphorylation of serine residue 863 (S863) in the GluA1 AMPAR subunit and controls surface trafficking of GluA1 in neurons. Activation of the EphR-Ephrin signal transduction pathway enhances S863 phosphorylation. Further, EphB2 can interact with Zizimin1, a guanine-nucleotide exchange factor that activates Cdc42 and stimulates S863 phosphorylation in neurons. Among the numerous targets downstream of Cdc42, we determined that the p21-activated kinase-3 (PAK3) phosphorylates S863 in vitro. Moreover, specific loss of PAK3 expression and pharmacological inhibition of PAK both disrupt activity-dependent phosphorylation of S863 in cortical neurons. EphB2, Cdc42, and PAKs are broadly capable of controlling dendritic spine formation and synaptic plasticity and are implicated in multiple cognitive disorders. Collectively, these data delineate a novel signal cascade regulating AMPAR trafficking that may contribute to the molecular mechanisms that govern learning and cognition.
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19
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Kang MG, Byun K, Kim JH, Park NH, Heinsen H, Ravid R, Steinbusch HW, Lee B, Park YM. Proteogenomics of the human hippocampus: The road ahead. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:788-97. [PMID: 25770686 DOI: 10.1016/j.bbapap.2015.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 02/10/2015] [Accepted: 02/15/2015] [Indexed: 12/26/2022]
Abstract
The hippocampus is one of the most essential components of the human brain and plays an important role in learning and memory. The hippocampus has drawn great attention from scientists and clinicians due to its clinical importance in diseases such as Alzheimer's disease (AD), non-AD dementia, and epilepsy. Understanding the function of the hippocampus and related disease mechanisms requires comprehensive knowledge of the orchestration of the genome, epigenome, transcriptome, proteome, and post-translational modifications (PTMs) of proteins. The past decade has seen remarkable advances in the high-throughput sequencing techniques that are collectively called next generation sequencing (NGS). NGS enables the precise analysis of gene expression profiles in cells and tissues, allowing powerful and more feasible integration of expression data from the gene level to the protein level, even allowing "-omic" level assessment of PTMs. In addition, improved bioinformatics algorithms coupled with NGS technology are finally opening a new era for scientists to discover previously unidentified and elusive proteins. In the present review, we will focus mainly on the proteomics of the human hippocampus with an emphasis on the integrated analysis of genomics, epigenomics, transcriptomics, and proteomics. Finally, we will discuss our perspectives on the potential and future of proteomics in the field of hippocampal biology. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.
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Affiliation(s)
- Myoung-Goo Kang
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Graduate School of Medical Science & Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Kyunghee Byun
- Center for Genomics and Proteomics, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-840, Republic of Korea
| | - Jae Ho Kim
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea
| | - Nam Hyun Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Helmut Heinsen
- Morphological Brain Research Unit, Department of Psychiatry, Universität of Würzburg, Würzburg, Germany
| | - Rivka Ravid
- Brain Bank Consultant, Amsterdam, The Netherlands
| | - Harry W Steinbusch
- School for Mental Health and Neuroscience, Department of Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Bonghee Lee
- Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea.
| | - Young Mok Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea.
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20
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Abstract
Using a comprehensive proteomic approach, Schwenk et al. (2014), in this issue of Neuron, resolve the differential composition of AMPA receptor complexes in brain regions and through development. This work reveals a specificity in AMPA receptor complex assembly that is dynamic in both space and time.
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Affiliation(s)
- Mark O Collins
- Department of Biomedical Science and Centre for Membrane Interactions and Dynamics (CMIAD), Firth Court, Western Bank, The University of Sheffield, Sheffield S10 2TN, UK.
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21
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Chen N, Pandya NJ, Koopmans F, Castelo-Székelv V, van der Schors RC, Smit AB, Li KW. Interaction proteomics reveals brain region-specific AMPA receptor complexes. J Proteome Res 2014; 13:5695-706. [PMID: 25337787 DOI: 10.1021/pr500697b] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Fast excitatory synaptic transmission in the brain is mediated by glutamate acting on postsynaptic AMPA receptors. Recent studies have revealed a substantial number of AMPA receptor auxiliary proteins, which potentially contribute to the regulation of AMPA receptor trafficking, subcellular receptor localization, and receptor gating properties. Here we examined the AMPA receptor interactomes from cortex, hippocampus, and cerebellum by comprehensive interaction proteomics. The study reveals that AMPA receptor auxiliary proteins are engaged in distinct brain region-specific AMPA receptors subcomplexes, which might underlie brain region-specific differential regulation of AMPA receptor properties. Depending on the brain region, an interacting protein can be involved in an AMPA and a non-AMPA receptor complex.
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Affiliation(s)
- Ning Chen
- Department of Molecular and Cellular Neurobiology, and ‡Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University , De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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22
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FXR1P limits long-term memory, long-lasting synaptic potentiation, and de novo GluA2 translation. Cell Rep 2014; 9:1402-1416. [PMID: 25456134 DOI: 10.1016/j.celrep.2014.10.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/28/2014] [Accepted: 10/11/2014] [Indexed: 12/31/2022] Open
Abstract
Translational control of mRNAs allows for rapid and selective changes in synaptic protein expression that are required for long-lasting plasticity and memory formation in the brain. Fragile X Related Protein 1 (FXR1P) is an RNA-binding protein that controls mRNA translation in nonneuronal cells and colocalizes with translational machinery in neurons. However, its neuronal mRNA targets and role in the brain are unknown. Here, we demonstrate that removal of FXR1P from the forebrain of postnatal mice selectively enhances long-term storage of spatial memories, hippocampal late-phase long-term potentiation (L-LTP), and de novo GluA2 synthesis. Furthermore, FXR1P binds specifically to the 5' UTR of GluA2 mRNA to repress translation and limit the amount of GluA2 that is incorporated at potentiated synapses. This study uncovers a mechanism for regulating long-lasting synaptic plasticity and spatial memory formation and reveals an unexpected divergent role of FXR1P among Fragile X proteins in brain plasticity.
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23
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Abstract
Cornichon homologs (CNIHs) are AMPA-type glutamate receptor (AMPAR) auxiliary subunits that modulate AMPAR ion channel function and trafficking. Mechanisms underlying this interaction and functional modulation of the receptor complex are currently unclear. Here, using proteins expressed from mouse and rat cDNA, we show that CNIH-3 forms a stable complex with tetrameric AMPARs and contributes to the transmembrane density in single-particle electron microscopy structures. Peptide array-based screening and in vitro mutagenesis identified two clusters of conserved membrane-proximal residues in CNIHs that contribute to AMPAR binding. Because CNIH-1 binds to AMPARs but modulates gating at a significantly lower magnitude compared with CNIH-3, these conserved residues mediate a direct interaction between AMPARs and CNIHs. In addition, residues in the extracellular loop of CNIH-2/3 absent in CNIH-1/4 are critical for both AMPAR interaction and gating modulation. On the AMPAR extracellular domains, the ligand-binding domain and possibly a stretch of linker, connecting the ligand-binding domain to the fourth membrane-spanning segment, is the principal contact point with the CNIH-3 extracellular loop. In contrast, the membrane-distal N-terminal domain is less involved in AMPAR gating modulation by CNIH-3 and AMPAR binding to CNIH-3. Collectively, our results identify conserved residues in the membrane-proximal region of CNIHs that contribute to AMPAR binding and an additional unique segment in the CNIH-2/3 extracellular loop required for both physical interaction and gating modulation of the AMPAR. Consistent with the dissociable properties of binding and gating modulation, we identified a mutant CNIH-3 that preserves AMPAR binding capability but has attenuated activity of gating modulation.
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24
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Juranek JK, Mukherjee K, Siddiqui TJ, Kaplan BJ, Li JY, Ahnert-Hilger G, Jahn R, Calka J. Active zone protein expression changes at the key stages of cerebellar cortex neurogenesis in the rat. Acta Histochem 2013; 115:616-25. [PMID: 23434052 DOI: 10.1016/j.acthis.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 12/11/2022]
Abstract
Signal transduction and neurotransmitter release in the vertebrate central nervous system are confined to the structurally complex presynaptic electron dense projections called "active zones." Although the nature of these projections remains a mystery, genetic and biochemical work has provided evidence for the active zone (AZ) associated proteins i.e. Piccolo/Aczonin, Bassoon, RIM1/Unc10, Munc13/Unc13, Liprin-α/SYD2/Dliprin and ELKS/CAST/BRP and their specific molecular functions. It still remains unclear, however, what their precise contribution is to the AZ assembly. In our project, we studied in Wistar rats the temporal and spatial distribution of AZ proteins and their colocalization with Synaptophysin in the developing cerebellar cortex at key stages of cerebellum neurogenesis. Our study demonstrated that AZ proteins were already present at the very early stages of cerebellar neurogenesis and exhibited distinct spatial and temporal variations in immunoexpression throughout the course of the study. Colocalization analysis revealed that the colocalization pattern was time-dependent and different for each studied protein. The highest collective mean percentage of colocalization (>85%) was observed at postnatal day (PD) 5, followed by PD10 (>83%) and PD15 (>80%). The findings of our study shed light on AZ protein immunoexpression changes during cerebellar cortex neurogenesis and help frame a hypothetical model of AZ assembly.
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25
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Wen S, Schroeter A, Klöcker N. Synaptic plasticity in hepatic encephalopathy - a molecular perspective. Arch Biochem Biophys 2013; 536:183-8. [PMID: 23624147 DOI: 10.1016/j.abb.2013.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 01/04/2023]
Abstract
Hepatic encephalopathy (HE)(1) is a common neuropsychiatric complication of both acute and chronic liver disease. Clinical symptoms may include motor disturbances and cognitive dysfunction. Available animal models of HE mimic the deficits in cognitive performance including the impaired ability to learn and memorize information. This review explores the question how HE might affect cognitive functions at molecular levels. Both acute and chronic models of HE constrain the plasticity of glutamatergic neurotransmission. Thus, long-lasting activity-dependent changes in synaptic efficiency, known as long-term potentiation (LTP) and long-term depression (LTD) are significantly impeded. We discuss molecules and signal transduction pathways of LTP and LTD that are targeted by experimental HE, with a focus on ionotropic glutamate receptors of the AMPA-subtype. Finally, a novel strategy of functional proteomic analysis is presented, which, if applied differentially, may provide molecular insight into disease-related dysfunction of membrane protein complexes, i.e. disturbed ionotropic glutamate receptor signaling in HE.
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Affiliation(s)
- Shuping Wen
- Institute of Neural and Sensory Physiology, Medical Faculty, University of Düsseldorf D-40225 Düsseldorf, Germany
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