1
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Petzoldt AG. Presynaptic Precursor Vesicles-Cargo, Biogenesis, and Kinesin-Based Transport across Species. Cells 2023; 12:2248. [PMID: 37759474 PMCID: PMC10527734 DOI: 10.3390/cells12182248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/11/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
The faithful formation and, consequently, function of a synapse requires continuous and tightly controlled delivery of synaptic material. At the presynapse, a variety of proteins with unequal molecular properties are indispensable to compose and control the molecular machinery concerting neurotransmitter release through synaptic vesicle fusion with the presynaptic membrane. As presynaptic proteins are produced mainly in the neuronal soma, they are obliged to traffic along microtubules through the axon to reach the consuming presynapse. This anterograde transport is performed by highly specialised and diverse presynaptic precursor vesicles, membranous organelles able to transport as different proteins such as synaptic vesicle membrane and membrane-associated proteins, cytosolic active zone proteins, ion-channels, and presynaptic membrane proteins, coordinating synaptic vesicle exo- and endocytosis. This review aims to summarise and categorise the diverse and numerous findings describing presynaptic precursor cargo, mode of trafficking, kinesin-based axonal transport and the molecular mechanisms of presynaptic precursor vesicles biogenesis in both vertebrate and invertebrate model systems.
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Affiliation(s)
- Astrid G Petzoldt
- Institute for Biology and Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
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2
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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3
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Cunningham KL, Sauvola CW, Tavana S, Littleton JT. Regulation of presynaptic Ca 2+ channel abundance at active zones through a balance of delivery and turnover. eLife 2022; 11:78648. [PMID: 35833625 PMCID: PMC9352347 DOI: 10.7554/elife.78648] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/13/2022] [Indexed: 12/03/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) mediate Ca2+ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (Pr), a key presynaptic determinant of synaptic strength. Although biosynthesis, delivery, and recycling cooperate to establish AZ VGCC abundance, experimentally isolating these distinct regulatory processes has been difficult. Here, we describe how the AZ levels of cacophony (Cac), the sole VGCC-mediating synaptic transmission in Drosophila, are determined. We also analyzed the relationship between Cac, the conserved VGCC regulatory subunit α2δ, and the core AZ scaffold protein Bruchpilot (BRP) in establishing a functional AZ. We find that Cac and BRP are independently regulated at growing AZs, as Cac is dispensable for AZ formation and structural maturation, and BRP abundance is not limiting for Cac accumulation. Additionally, AZs stop accumulating Cac after an initial growth phase, whereas BRP levels continue to increase given extended developmental time. AZ Cac is also buffered against moderate increases or decreases in biosynthesis, whereas BRP lacks this buffering. To probe mechanisms that determine AZ Cac abundance, intravital FRAP and Cac photoconversion were used to separately measure delivery and turnover at individual AZs over a multi-day period. Cac delivery occurs broadly across the AZ population, correlates with AZ size, and is rate-limited by α2δ. Although Cac does not undergo significant lateral transfer between neighboring AZs over the course of development, Cac removal from AZs does occur and is promoted by new Cac delivery, generating a cap on Cac accumulation at mature AZs. Together, these findings reveal how Cac biosynthesis, synaptic delivery, and recycling set the abundance of VGCCs at individual AZs throughout synapse development and maintenance.
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Affiliation(s)
- Karen L Cunningham
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Chad W Sauvola
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Sara Tavana
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
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4
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Knodel MM, Dutta Roy R, Wittum G. Influence of T-Bar on Calcium Concentration Impacting Release Probability. Front Comput Neurosci 2022; 16:855746. [PMID: 35586479 PMCID: PMC9108211 DOI: 10.3389/fncom.2022.855746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/09/2022] [Indexed: 11/25/2022] Open
Abstract
The relation of form and function, namely the impact of the synaptic anatomy on calcium dynamics in the presynaptic bouton, is a major challenge of present (computational) neuroscience at a cellular level. The Drosophila larval neuromuscular junction (NMJ) is a simple model system, which allows studying basic effects in a rather simple way. This synapse harbors several special structures. In particular, in opposite to standard vertebrate synapses, the presynaptic boutons are rather large, and they have several presynaptic zones. In these zones, different types of anatomical structures are present. Some of the zones bear a so-called T-bar, a particular anatomical structure. The geometric form of the T-bar resembles the shape of the letter “T” or a table with one leg. When an action potential arises, calcium influx is triggered. The probability of vesicle docking and neurotransmitter release is superlinearly proportional to the concentration of calcium close to the vesicular release site. It is tempting to assume that the T-bar causes some sort of calcium accumulation and hence triggers a higher release probability and thus enhances neurotransmitter exocytosis. In order to study this influence in a quantitative manner, we constructed a typical T-bar geometry and compared the calcium concentration close to the active zones (AZs). We compared the case of synapses with and without T-bars. Indeed, we found a substantial influence of the T-bar structure on the presynaptic calcium concentrations close to the AZs, indicating that this anatomical structure increases vesicle release probability. Therefore, our study reveals how the T-bar zone implies a strong relation between form and function. Our study answers the question of experimental studies (namely “Wichmann and Sigrist, Journal of neurogenetics 2010”) concerning the sense of the anatomical structure of the T-bar.
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Affiliation(s)
- Markus M. Knodel
- Goethe Center for Scientific Computing (GCSC), Goethe Universität Frankfurt, Frankfurt, Germany
- *Correspondence: Markus M. Knodel ; orcid.org/0000-0001-8739-0803
| | | | - Gabriel Wittum
- Goethe Center for Scientific Computing (GCSC), Goethe Universität Frankfurt, Frankfurt, Germany
- Applied Mathematics and Computational Science, Computer, Electrical and Mathematical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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5
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Götz TWB, Puchkov D, Lysiuk V, Lützkendorf J, Nikonenko AG, Quentin C, Lehmann M, Sigrist SJ, Petzoldt AG. Rab2 regulates presynaptic precursor vesicle biogenesis at the trans-Golgi. J Cell Biol 2021; 220:211946. [PMID: 33822845 PMCID: PMC8025234 DOI: 10.1083/jcb.202006040] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 02/08/2021] [Accepted: 02/26/2021] [Indexed: 11/22/2022] Open
Abstract
Reliable delivery of presynaptic material, including active zone and synaptic vesicle proteins from neuronal somata to synaptic terminals, is prerequisite for successful synaptogenesis and neurotransmission. However, molecular mechanisms controlling the somatic assembly of presynaptic precursors remain insufficiently understood. We show here that in mutants of the small GTPase Rab2, both active zone and synaptic vesicle proteins accumulated in the neuronal cell body at the trans-Golgi and were, consequently, depleted at synaptic terminals, provoking neurotransmission deficits. Ectopic presynaptic material accumulations consisted of heterogeneous vesicles and short tubules of 40 × 60 nm, segregating in subfractions either positive for active zone or synaptic vesicle proteins and LAMP1, a lysosomal membrane protein. Genetically, Rab2 acts upstream of Arl8, a lysosomal adaptor controlling axonal export of precursors. Collectively, we identified a Golgi-associated assembly sequence of presynaptic precursor biogenesis dependent on a Rab2-regulated protein export and sorting step at the trans-Golgi.
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Affiliation(s)
- Torsten W B Götz
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin e.V., Campus Berlin-Buch, Berlin, Germany
| | - Veronika Lysiuk
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | - Janine Lützkendorf
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | | | - Christine Quentin
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin e.V., Campus Berlin-Buch, Berlin, Germany
| | - Stephan J Sigrist
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany.,NeuroCure, Charité, Berlin, Germany
| | - Astrid G Petzoldt
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
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6
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Xie X, Liang M, Yu C, Wei Z. Liprin-α-Mediated Assemblies and Their Roles in Synapse Formation. Front Cell Dev Biol 2021; 9:653381. [PMID: 33869211 PMCID: PMC8044993 DOI: 10.3389/fcell.2021.653381] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/25/2021] [Indexed: 01/20/2023] Open
Abstract
Brain's functions, such as memory and learning, rely on synapses that are highly specialized cellular junctions connecting neurons. Functional synapses orchestrate the assembly of ion channels, receptors, enzymes, and scaffold proteins in both pre- and post-synapse. Liprin-α proteins are master scaffolds in synapses and coordinate various synaptic proteins to assemble large protein complexes. The functions of liprin-αs in synapse formation have been largely uncovered by genetic studies in diverse model systems. Recently, emerging structural and biochemical studies on liprin-α proteins and their binding partners begin to unveil the molecular basis of the synaptic assembly. This review summarizes the recent structural findings on liprin-αs, proposes the assembly mechanism of liprin-α-mediated complexes, and discusses the liprin-α-organized assemblies in the regulation of synapse formation and function.
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Affiliation(s)
- Xingqiao Xie
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
| | - Mingfu Liang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Cong Yu
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, China
| | - Zhiyi Wei
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Brain Research Center, Southern University of Science and Technology, Shenzhen, China
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7
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Ramesh N, Escher MJF, Mampell MM, Böhme MA, Götz TWB, Goel P, Matkovic T, Petzoldt AG, Dickman D, Sigrist SJ. Antagonistic interactions between two Neuroligins coordinate pre- and postsynaptic assembly. Curr Biol 2021; 31:1711-1725.e5. [PMID: 33651992 DOI: 10.1016/j.cub.2021.01.093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/18/2020] [Accepted: 01/26/2021] [Indexed: 12/17/2022]
Abstract
As a result of developmental synapse formation, the presynaptic neurotransmitter release machinery becomes accurately matched with postsynaptic neurotransmitter receptors. Trans-synaptic signaling is executed through cell adhesion proteins such as Neurexin::Neuroligin pairs but also through diffusible and cytoplasmic signals. How exactly pre-post coordination is ensured in vivo remains largely enigmatic. Here, we identified a "molecular choreography" coordinating pre- with postsynaptic assembly during the developmental formation of Drosophila neuromuscular synapses. Two presynaptic Neurexin-binding scaffold proteins, Syd-1 and Spinophilin (Spn), spatio-temporally coordinated pre-post assembly in conjunction with two postsynaptically operating, antagonistic Neuroligin species: Nlg1 and Nlg2. The Spn/Nlg2 module promoted active zone (AZ) maturation by driving the accumulation of AZ scaffold proteins critical for synaptic vesicle release. Simultaneously, these regulators restricted postsynaptic glutamate receptor incorporation. Both functions of the Spn/Nlg2 module were directly antagonized by Syd-1/Nlg1. Nlg1 and Nlg2 also had divergent effects on Nrx-1 in vivo motility. Concerning diffusible signals, Spn and Syd-1 antagonistically controlled the levels of Munc13-family protein Unc13B at nascent AZs, whose release function facilitated glutamate receptor incorporation at assembling postsynaptic specializations. As a result, we here provide direct in vivo evidence illustrating how a highly regulative and interleaved communication between cell adhesion protein signaling complexes and diffusible signals allows for a precise coordination of pre- with postsynaptic assembly. It will be interesting to analyze whether this logic also transfers to plasticity processes.
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Affiliation(s)
- Niraja Ramesh
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Malou M Mampell
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Mathias A Böhme
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Torsten W B Götz
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - Tanja Matkovic
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Astrid G Petzoldt
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - Stephan J Sigrist
- Institute for Biology and Genetics, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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8
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Liang M, Jin G, Xie X, Zhang W, Li K, Niu F, Yu C, Wei Z. Oligomerized liprin-α promotes phase separation of ELKS for compartmentalization of presynaptic active zone proteins. Cell Rep 2021; 34:108901. [PMID: 33761347 DOI: 10.1016/j.celrep.2021.108901] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/02/2021] [Accepted: 03/03/2021] [Indexed: 01/09/2023] Open
Abstract
Synaptic scaffold proteins (e.g., liprin-α, ELKS, RIM, and RIM-BP) orchestrate ion channels, receptors, and enzymes at presynaptic terminals to form active zones for neurotransmitter release. The underlying mechanism of the active zone assembly remains elusive. Here, we report that liprin-α proteins have the potential to oligomerize through the N-terminal coiled-coil region. Our structural and biochemical characterizations reveal that a gain-of-function mutation promotes the self-assembly of the coiled coils in liprin-α2 by disrupting intramolecular interactions and promoting intermolecular interactions. By enabling multivalent interactions with ELKS proteins, the oligomerized coiled-coil region of liprin-α2 enhances the phase separation of the ELKS N-terminal segment. We further show that liprin-α2, by regulating the interplay between two phase separations of ELKS and RIM/RIM-BP, controls the protein distributions. These results imply that the complicated protein-protein interactions allow liprin-α to function with the active zone scaffolds and compartmentalize protein assemblies to achieve comprehensive functions in the active zone.
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Affiliation(s)
- Mingfu Liang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Gaowei Jin
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xingqiao Xie
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Wenchao Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Kaiyue Li
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Fengfeng Niu
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Cong Yu
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, and Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, Guangdong 518055, China.
| | - Zhiyi Wei
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Brain Research Center, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
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9
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Gao T, Zhang Z, Yang Y, Zhang H, Li N, Liu B. Impact of RIM-BPs in neuronal vesicles release. Brain Res Bull 2021; 170:129-136. [PMID: 33581313 DOI: 10.1016/j.brainresbull.2021.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Accurate signal transmission between neurons is accomplished by vesicle release with high spatiotemporal resolution in the central nervous system. The vesicle release occurs mainly in the active zone (AZ), a unique area on the presynaptic membrane. Many structural proteins expressed in the AZ connect with other proteins nearby. They can also regulate the precise release of vesicles through protein-protein interactions. RIM-binding proteins (RIM-BPs) are one of the essential proteins in the AZ. This review summarizes the structures and functions of three subtypes of RIM-BPs, including the interaction between RIM-BPs and other proteins such as Bassoon and voltage-gated calcium channel, their significance in stabilizing the AZ structure in the presynaptic region and collecting ion channels, and ultimately regulating the fusion and release of neuronal vesicles.
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Affiliation(s)
- Tianyu Gao
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Zhengyao Zhang
- School of Life and Pharmaceutical Sciences, Panjin Campus of Dalian University of Technology, Panjin, 124221, China
| | - Yunong Yang
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Hangyu Zhang
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Na Li
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China.
| | - Bo Liu
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China.
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10
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Chou VT, Johnson SA, Van Vactor D. Synapse development and maturation at the drosophila neuromuscular junction. Neural Dev 2020; 15:11. [PMID: 32741370 PMCID: PMC7397595 DOI: 10.1186/s13064-020-00147-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
Synapses are the sites of neuron-to-neuron communication and form the basis of the neural circuits that underlie all animal cognition and behavior. Chemical synapses are specialized asymmetric junctions between a presynaptic neuron and a postsynaptic target that form through a series of diverse cellular and subcellular events under the control of complex signaling networks. Once established, the synapse facilitates neurotransmission by mediating the organization and fusion of synaptic vesicles and must also retain the ability to undergo plastic changes. In recent years, synaptic genes have been implicated in a wide array of neurodevelopmental disorders; the individual and societal burdens imposed by these disorders, as well as the lack of effective therapies, motivates continued work on fundamental synapse biology. The properties and functions of the nervous system are remarkably conserved across animal phyla, and many insights into the synapses of the vertebrate central nervous system have been derived from studies of invertebrate models. A prominent model synapse is the Drosophila melanogaster larval neuromuscular junction, which bears striking similarities to the glutamatergic synapses of the vertebrate brain and spine; further advantages include the simplicity and experimental versatility of the fly, as well as its century-long history as a model organism. Here, we survey findings on the major events in synaptogenesis, including target specification, morphogenesis, and the assembly and maturation of synaptic specializations, with a emphasis on work conducted at the Drosophila neuromuscular junction.
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Affiliation(s)
- Vivian T Chou
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Seth A Johnson
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA.
| | - David Van Vactor
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA.
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11
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Ho CH, Treisman JE. Specific Isoforms of the Guanine-Nucleotide Exchange Factor dPix Couple Neuromuscular Synapse Growth to Muscle Growth. Dev Cell 2020; 54:117-131.e5. [PMID: 32516570 DOI: 10.1016/j.devcel.2020.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/09/2020] [Accepted: 05/13/2020] [Indexed: 12/28/2022]
Abstract
Developmental growth requires coordination between the growth rates of individual tissues and organs. Here, we examine how Drosophila neuromuscular synapses grow to match the size of their target muscles. We show that changes in muscle growth driven by autonomous modulation of insulin receptor signaling produce corresponding changes in synapse size, with each muscle affecting only its presynaptic motor neuron branches. This scaling growth is mechanistically distinct from synaptic plasticity driven by neuronal activity and requires increased postsynaptic differentiation induced by insulin receptor signaling in muscle. We identify the guanine-nucleotide exchange factor dPix as an effector of insulin receptor signaling. Alternatively spliced dPix isoforms that contain a specific exon are necessary and sufficient for postsynaptic differentiation and scaling growth, and their mRNA levels are regulated by insulin receptor signaling. These findings define a mechanism by which the same signaling pathway promotes both autonomous muscle growth and non-autonomous synapse growth.
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Affiliation(s)
- Cheuk Hei Ho
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
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12
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Tomoda T, Yang K, Sawa A. Neuronal Autophagy in Synaptic Functions and Psychiatric Disorders. Biol Psychiatry 2020; 87:787-796. [PMID: 31542152 PMCID: PMC6986983 DOI: 10.1016/j.biopsych.2019.07.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/02/2019] [Accepted: 07/19/2019] [Indexed: 12/22/2022]
Abstract
Homeostatic maintenance of physiological functions is fundamental to organismal well-being. Disruption or imbalance in homeostasis results in functional disturbances at molecular, cellular, and tissue levels, leading to manifestation as physical and mental illnesses. Homeostatic imbalance is caused by a range of pathophysiological mechanisms, including disrupted reduction-oxidation reactions, inflammatory responses, metabolic disturbances, or failure in quality control of cellular proteins and organelles. However, the roles for the protein/organelle quality control in the regulation of behaviors, in particular of cognitive processes, had not been well documented, until recent reports finally supported this concept. The frontline studies in neuroscience have revealed that synaptic components (e.g., synaptic proteins, organelles, neurotransmitters and their receptors) are selectively degraded by autophagy, a cellular recycling machinery implicated in surveillance and quality control of proteins and organelles responsible for the maintenance of cellular homeostasis. Apart from the canonical role of autophagy in supporting cell viability, synaptic autophagy appears to regulate synapse remodeling and plasticity. Consistently, emerging evidence suggests novel roles of autophagy in memory encoding, information processing, or cognitive functions. In this review, we overview recent progress in understanding the roles of neuronal autophagy in homeostatic maintenance of synaptic functions, with particular focus on how disruptions in these processes may contribute to the pathophysiology of psychiatric disorders.
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Affiliation(s)
- Toshifumi Tomoda
- Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada.
| | - Kun Yang
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Akira Sawa
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
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13
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Galanis C, Vlachos A. Hebbian and Homeostatic Synaptic Plasticity-Do Alterations of One Reflect Enhancement of the Other? Front Cell Neurosci 2020; 14:50. [PMID: 32256317 PMCID: PMC7093376 DOI: 10.3389/fncel.2020.00050] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/21/2020] [Indexed: 01/07/2023] Open
Abstract
During the past 50 years, the cellular and molecular mechanisms of synaptic plasticity have been studied in great detail. A plethora of signaling pathways have been identified that account for synaptic changes based on positive and negative feedback mechanisms. Yet, the biological significance of Hebbian synaptic plasticity (= positive feedback) and homeostatic synaptic plasticity (= negative feedback) remains a matter of debate. Specifically, it is unclear how these opposing forms of plasticity, which share common downstream mechanisms, operate in the same networks, neurons, and synapses. Based on the observation that rapid and input-specific homeostatic mechanisms exist, we here discuss a model that is based on signaling pathways that may adjust a balance between Hebbian and homeostatic synaptic plasticity. Hence, “alterations” in Hebbian plasticity may, in fact, resemble “enhanced” homeostasis, which rapidly returns synaptic strength to baseline. In turn, long-lasting experience-dependent synaptic changes may require attenuation of homeostatic mechanisms or the adjustment of homeostatic setpoints at the single-synapse level. In this context, we propose a role for the proteolytic processing of the amyloid precursor protein (APP) in setting a balance between the ability of neurons to express Hebbian and homeostatic synaptic plasticity.
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Affiliation(s)
- Christos Galanis
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
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14
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Ashida K, Shidara H, Hotta K, Oka K. Optical Dissection of Synaptic Plasticity for Early Adaptation in Caenorhabditis elegans. Neuroscience 2020; 428:112-121. [PMID: 31917348 DOI: 10.1016/j.neuroscience.2019.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 10/25/2022]
Abstract
To understand neuronal information processing, it is essential to investigate the input-output relationship and its modulation via detailed dissections of synaptic transmission between pre- and postsynaptic neurons. In Caenorhabditis elegans, pre-exposure to an odorant for five minutes reduces chemotaxis (early adaptation). AWC sensory neurons and AIY interneurons are crucial for this adaptation; AWC neurons sense volatile odors, and AIY interneurons receive glutamatergic inputs from AWC neurons. However, modulations via early adaptation of the input-output relationship between AWC and AIY are not well characterized. Here we use a variety of fluorescent imaging techniques to show that reduced synaptic-vesicle release without Ca2+ modulation in AWC neurons suppresses the Ca2+ response in AIY neurons via early adaptation. First, early adaptation modulates the Ca2+ response in AIY but not AWC neurons. Adaptation in the Ca2+ signal measured in AIY neurons is caused by adaptation in glutamate release from AWC neurons. Further, we found that a G protein γ-subunit, GPC-1, is related to modulation of glutamate input to AIY. Our results dissect the modulation of the pre- and postsynaptic relationship in vivo based on optical methods, and demonstrate the importance of neurotransmitter-release modulation in presynaptic neurons without Ca2+ modulation.
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Affiliation(s)
- Keita Ashida
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
| | - Hisashi Shidara
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
| | - Kohji Hotta
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
| | - Kotaro Oka
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan; Waseda Research Institute for Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku, Tokyo 162-8480, Japan.
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15
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Lipton DM, Maeder CI, Shen K. Rapid Assembly of Presynaptic Materials behind the Growth Cone in Dopaminergic Neurons Is Mediated by Precise Regulation of Axonal Transport. Cell Rep 2019; 24:2709-2722. [PMID: 30184504 PMCID: PMC6179448 DOI: 10.1016/j.celrep.2018.07.096] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 06/21/2018] [Accepted: 07/27/2018] [Indexed: 11/15/2022] Open
Abstract
The proper assembly of neural circuits depends on the process of synaptogenesis, or the formation of synapses between partner neurons. Using the dopaminergic PDE neurons in C. elegans, we developed an in vivo system to study the earliest steps of the formation of en passant presynaptic specializations behind an extending growth cone. We find that presynaptic materials coalesce into puncta in as little as a few minutes and that both synaptic vesicle (SV) and active zone (AZ) proteins arrive nearly simultaneously at the nascent sites of synapse formation. We show that precise regulation of UNC-104/Kinesin-3 determines the distribution of SV proteins along the axon. The localization of AZ proteins to en passant puncta, however, is largely independent of the major axonal kinesins: UNC-104/Kinesin-3 and UNC-116/ Kinesin-1. Moreover, AZ proteins play a crucial role in recruiting and tethering SV precursors (SVPs). Lipton et al. explore the initial steps of synapse formation in vivo. They find that clustering of major presynaptic material occurs extremely rapidly (<5 min). Both synaptic vesicle precursors and active zone proteins accumulate simultaneously at developing puncta. Precise regulation of the Kinesin-3 activation state strongly influences the positioning of vesicles along the axon during development.
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Affiliation(s)
- David M Lipton
- Howard Hughes Medical Institute, Department of Biology, Stanford University, 385 Serra Mall, Stanford, CA 94305, USA; Neurosciences Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Celine I Maeder
- Howard Hughes Medical Institute, Department of Biology, Stanford University, 385 Serra Mall, Stanford, CA 94305, USA
| | - Kang Shen
- Howard Hughes Medical Institute, Department of Biology, Stanford University, 385 Serra Mall, Stanford, CA 94305, USA.
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16
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Fulterer A, Andlauer TFM, Ender A, Maglione M, Eyring K, Woitkuhn J, Lehmann M, Matkovic-Rachid T, Geiger JRP, Walter AM, Nagel KI, Sigrist SJ. Active Zone Scaffold Protein Ratios Tune Functional Diversity across Brain Synapses. Cell Rep 2019; 23:1259-1274. [PMID: 29719243 DOI: 10.1016/j.celrep.2018.03.126] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/28/2018] [Accepted: 03/27/2018] [Indexed: 01/20/2023] Open
Abstract
High-throughput electron microscopy has started to reveal synaptic connectivity maps of single circuits and whole brain regions, for example, in the Drosophila olfactory system. However, efficacy, timing, and frequency tuning of synaptic vesicle release are also highly diversified across brain synapses. These features critically depend on the nanometer-scale coupling distance between voltage-gated Ca2+ channels (VGCCs) and the synaptic vesicle release machinery. Combining light super resolution microscopy with in vivo electrophysiology, we show here that two orthogonal scaffold proteins (ELKS family Bruchpilot, BRP, and Syd-1) cluster-specific (M)Unc13 release factor isoforms either close (BRP/Unc13A) or further away (Syd-1/Unc13B) from VGCCs across synapses of the Drosophila olfactory system, resulting in different synapse-characteristic forms of short-term plasticity. Moreover, BRP/Unc13A versus Syd-1/Unc13B ratios were different between synapse types. Thus, variation in tightly versus loosely coupled scaffold protein/(M)Unc13 modules can tune synapse-type-specific release features, and "nanoscopic molecular fingerprints" might identify synapses with specific temporal features.
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Affiliation(s)
- Andreas Fulterer
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Till F M Andlauer
- Max Planck Institute of Psychiatry, 80804 Munich, Germany; Department of Neurology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Anatoli Ender
- German Center for Neurodegenerative Disorders, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, 10117 Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Katherine Eyring
- Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Jennifer Woitkuhn
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | | | - Joerg R P Geiger
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, 10117 Berlin, Germany; Institut für Neurophysiologie, Charité Universitätsmedizin, 10117 Berlin, Germany
| | - Alexander M Walter
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Katherine I Nagel
- Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA.
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, 10117 Berlin, Germany.
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17
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Two Pathways for the Activity-Dependent Growth and Differentiation of Synaptic Boutons in Drosophila. eNeuro 2019; 6:ENEURO.0060-19.2019. [PMID: 31387877 PMCID: PMC6709223 DOI: 10.1523/eneuro.0060-19.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/15/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022] Open
Abstract
Synapse formation can be promoted by intense activity. At the Drosophila larval neuromuscular junction (NMJ), new synaptic boutons can grow acutely in response to patterned stimulation. We combined confocal imaging with electron microscopy and tomography to investigate the initial stages of growth and differentiation of new presynaptic boutons at the Drosophila NMJ. We found that the new boutons can form rapidly in intact larva in response to intense crawling activity, and we observed two different patterns of bouton formation and maturation. The first pathway involves the growth of filopodia followed by a formation of boutons that are initially devoid of synaptic vesicles (SVs) but filled with filamentous matrix. The second pathway involves rapid budding of synaptic boutons packed with SVs, and these more mature boutons are sometimes capable of exocytosis/endocytosis. We demonstrated that intense activity predominantly promotes the second pathway, i.e., budding of more mature boutons filled with SVs. We also showed that this pathway depends on synapsin (Syn), a neuronal protein which reversibly associates with SVs and mediates their clustering via a protein kinase A (PKA)-dependent mechanism. Finally, we took advantage of the temperature-sensitive mutant sei to demonstrate that seizure activity can promote very rapid budding of new boutons filled with SVs, and this process occurs at scale of minutes. Altogether, these results demonstrate that intense activity acutely and selectively promotes rapid budding of new relatively mature presynaptic boutons filled with SVs, and that this process is regulated via a PKA/Syn-dependent pathway.
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18
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Liang Y. Emerging Concepts and Functions of Autophagy as a Regulator of Synaptic Components and Plasticity. Cells 2019; 8:cells8010034. [PMID: 30634508 PMCID: PMC6357011 DOI: 10.3390/cells8010034] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/23/2018] [Accepted: 01/03/2019] [Indexed: 12/15/2022] Open
Abstract
Protein homeostasis (proteostasis) is crucial to the maintenance of neuronal integrity and function. As the contact sites between neurons, synapses rely heavily on precisely regulated protein-protein interactions to support synaptic transmission and plasticity processes. Autophagy is an effective degradative pathway that can digest cellular components and maintain cellular proteostasis. Perturbations of autophagy have been implicated in aging and neurodegeneration due to a failure to remove damaged proteins and defective organelles. Recent evidence has demonstrated that autophagosome formation is prominent at synaptic terminals and neuronal autophagy is regulated in a compartment-specific fashion. Moreover, synaptic components including synaptic proteins and vesicles, postsynaptic receptors and synaptic mitochondria are known to be degraded by autophagy, thereby contributing to the remodeling of synapses. Indeed, emerging studies indicate that modulation of autophagy may be required for different forms of synaptic plasticity and memory formation. In this review, I will discuss our current understanding of the important role of neuronal/synaptic autophagy in maintaining neuronal function by degrading synaptic components and try to propose a conceptual framework of how the degradation of synaptic components via autophagy might impact synaptic function and contribute to synaptic plasticity.
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Affiliation(s)
- YongTian Liang
- Neurogenetik, Institut für Biologie, Freie Universität Berlin, 14195 Berlin, Germany.
- NeuroCure, Cluster of Excellence, Charité Universitätsmedizin, 10117 Berlin, Germany.
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19
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Han KA, Um JW, Ko J. Intracellular protein complexes involved in synapse assembly in presynaptic neurons. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 116:347-373. [PMID: 31036296 DOI: 10.1016/bs.apcsb.2018.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The presynaptic active zone, composed of evolutionarily conserved protein complexes, is a specialized area that serves to orchestrate precise and efficient neurotransmitter release by organizing various presynaptic proteins involved in mediating docking and priming of synaptic vesicles, recruiting voltage-gated calcium channels, and modulating presynaptic nerve terminals with aligned postsynaptic structures. Among membrane proteins localized to active zone, presynaptic neurexins and LAR-RPTPs (leukocyte common antigen-related receptor tyrosine phosphatase) have emerged as hubs that orchestrate both shared and distinct extracellular synaptic adhesion pathways. In this chapter, we discuss intracellular signaling cascades involved in recruiting various intracellular proteins at both excitatory and inhibitory synaptic sites. In particular, we highlight recent studies on key active zone proteins that physically and functionally link these cascades with neurexins and LAR-RPTPs in both vertebrate and invertebrate model systems. These studies allow us to build a general, universal view of how presynaptic active zones operate together with postsynaptic structures in neural circuits.
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Affiliation(s)
- Kyung Ah Han
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea.
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20
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Ghelani T, Sigrist SJ. Coupling the Structural and Functional Assembly of Synaptic Release Sites. Front Neuroanat 2018; 12:81. [PMID: 30386217 PMCID: PMC6198076 DOI: 10.3389/fnana.2018.00081] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/18/2018] [Indexed: 01/04/2023] Open
Abstract
Information processing in our brains depends on the exact timing of calcium (Ca2+)-activated exocytosis of synaptic vesicles (SVs) from unique release sites embedded within the presynaptic active zones (AZs). While AZ scaffolding proteins obviously provide an efficient environment for release site function, the molecular design creating such release sites had remained unknown for a long time. Recent advances in visualizing the ultrastructure and topology of presynaptic protein architectures have started to elucidate how scaffold proteins establish “nanodomains” that connect voltage-gated Ca2+ channels (VGCCs) physically and functionally with release-ready SVs. Scaffold proteins here seem to operate as “molecular rulers or spacers,” regulating SV-VGCC physical distances within tens of nanometers and, thus, influence the probability and plasticity of SV release. A number of recent studies at Drosophila and mammalian synapses show that the stable positioning of discrete clusters of obligate release factor (M)Unc13 defines the position of SV release sites, and the differential expression of (M)Unc13 isoforms at synapses can regulate SV-VGCC coupling. We here review the organization of matured AZ scaffolds concerning their intrinsic organization and role for release site formation. Moreover, we also discuss insights into the developmental sequence of AZ assembly, which often entails a tightening between VGCCs and SV release sites. The findings discussed here are retrieved from vertebrate and invertebrate preparations and include a spectrum of methods ranging from cell biology, super-resolution light and electron microscopy to biophysical and electrophysiological analysis. Our understanding of how the structural and functional organization of presynaptic AZs are coupled has matured, as these processes are crucial for the understanding of synapse maturation and plasticity, and, thus, accurate information transfer and storage at chemical synapses.
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Affiliation(s)
- Tina Ghelani
- Faculty of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Stephan J Sigrist
- Faculty of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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21
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Hagiwara A, Kitahara Y, Grabner CP, Vogl C, Abe M, Kitta R, Ohta K, Nakamura K, Sakimura K, Moser T, Nishi A, Ohtsuka T. Cytomatrix proteins CAST and ELKS regulate retinal photoreceptor development and maintenance. J Cell Biol 2018; 217:3993-4006. [PMID: 30190286 PMCID: PMC6219712 DOI: 10.1083/jcb.201704076] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/18/2018] [Accepted: 08/03/2018] [Indexed: 01/06/2023] Open
Abstract
The retinal ribbon synapse is important for the processing of visual information. Hagiwara et al. show that the active zone proteins CAST and ELKS perform both redundant and unique functions in photoreceptors to promote the maturation, maintenance, and activity of ribbon synapses. At the presynaptic active zone (AZ), the related cytomatrix proteins CAST and ELKS organize the presynaptic release machinery. While CAST is known to regulate AZ size and neurotransmitter release, the role of ELKS and the integral system of CAST/ELKS together is poorly understood. Here, we show that CAST and ELKS have both redundant and unique roles in coordinating synaptic development, function, and maintenance of retinal photoreceptor ribbon synapses. A CAST/ELKS double knockout (dKO) mouse showed high levels of ectopic synapses and reduced responses to visual stimulation. Ectopic formation was not observed in ELKS conditional KO but progressively increased with age in CAST KO mice with higher rates in the dKO. Presynaptic calcium influx was strongly reduced in rod photoreceptors of CAST KO and dKO mice. Three-dimensional scanning EM reconstructions showed structural abnormalities in rod triads of CAST KO and dKO. Remarkably, AAV-mediated acute ELKS deletion after synapse maturation induced neurodegeneration and loss of ribbon synapses. These results suggest that CAST and ELKS work in concert to promote retinal synapse formation, transmission, and maintenance.
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Affiliation(s)
- Akari Hagiwara
- Department of Biochemistry, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Yosuke Kitahara
- Department of Pharmacology, Kurume University School of Medicine, Fukuoka, Japan
| | - Chad Paul Grabner
- Institute for Auditory Neuroscience and Inner Ear Lab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Christian Vogl
- Institute for Auditory Neuroscience and Inner Ear Lab, University Medical Center Göttingen, Göttingen, Germany
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Ryo Kitta
- Department of Biochemistry, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Keisuke Ohta
- Department of Anatomy, Kurume University School of Medicine, Fukuoka, Japan
| | - Keiichiro Nakamura
- Department of Anatomy, Kurume University School of Medicine, Fukuoka, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Tobias Moser
- Institute for Auditory Neuroscience and Inner Ear Lab, University Medical Center Göttingen, Göttingen, Germany .,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Akinori Nishi
- Department of Pharmacology, Kurume University School of Medicine, Fukuoka, Japan
| | - Toshihisa Ohtsuka
- Department of Biochemistry, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
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22
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Sugie A, Marchetti G, Tavosanis G. Structural aspects of plasticity in the nervous system of Drosophila. Neural Dev 2018; 13:14. [PMID: 29960596 PMCID: PMC6026517 DOI: 10.1186/s13064-018-0111-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 06/12/2018] [Indexed: 12/15/2022] Open
Abstract
Neurons extend and retract dynamically their neurites during development to form complex morphologies and to reach out to their appropriate synaptic partners. Their capacity to undergo structural rearrangements is in part maintained during adult life when it supports the animal's ability to adapt to a changing environment or to form lasting memories. Nonetheless, the signals triggering structural plasticity and the mechanisms that support it are not yet fully understood at the molecular level. Here, we focus on the nervous system of the fruit fly to ask to which extent activity modulates neuronal morphology and connectivity during development. Further, we summarize the evidence indicating that the adult nervous system of flies retains some capacity for structural plasticity at the synaptic or circuit level. For simplicity, we selected examples mostly derived from studies on the visual system and on the mushroom body, two regions of the fly brain with extensively studied neuroanatomy.
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Affiliation(s)
- Atsushi Sugie
- Center for Transdisciplinary Research, Niigata University, Niigata, 951-8585 Japan
- Brain Research Institute, Niigata University, Niigata, 951-8585 Japan
| | | | - Gaia Tavosanis
- Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
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23
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Genetic dissection of neuropeptide cell biology at high and low activity in a defined sensory neuron. Proc Natl Acad Sci U S A 2018; 115:E6890-E6899. [PMID: 29959203 PMCID: PMC6055185 DOI: 10.1073/pnas.1714610115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuropeptides are ubiquitous modulators of behavior and physiology. They are packaged in specialized secretory organelles called dense core vesicles (DCVs) that are released upon neural stimulation. Whereas local recycling of synaptic vesicles has been investigated intensively, there are few studies on recycling of DCV proteins. We set up a paradigm to study DCVs in a neuron whose activity we can control. We validate our model by confirming many previous observations on DCV cell biology. We identify a set of genes involved in recycling of DCV proteins. We also find evidence that different mechanisms of DCV priming and exocytosis may operate at high and low neural activity. Neuropeptides are ubiquitous modulators of behavior and physiology. They are packaged in specialized secretory organelles called dense core vesicles (DCVs) that are released upon neural stimulation. Unlike synaptic vesicles, which can be recycled and refilled close to release sites, DCVs must be replenished by de novo synthesis in the cell body. Here, we dissect DCV cell biology in vivo in a Caenorhabditis elegans sensory neuron whose tonic activity we can control using a natural stimulus. We express fluorescently tagged neuropeptides in the neuron and define parameters that describe their subcellular distribution. We measure these parameters at high and low neural activity in 187 mutants defective in proteins implicated in membrane traffic, neuroendocrine secretion, and neuronal or synaptic activity. Using unsupervised hierarchical clustering methods, we analyze these data and identify 62 groups of genes with similar mutant phenotypes. We explore the function of a subset of these groups. We recapitulate many previous findings, validating our paradigm. We uncover a large battery of proteins involved in recycling DCV membrane proteins, something hitherto poorly explored. We show that the unfolded protein response promotes DCV production, which may contribute to intertissue communication of stress. We also find evidence that different mechanisms of priming and exocytosis may operate at high and low neural activity. Our work provides a defined framework to study DCV biology at different neural activity levels.
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24
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Schrod N, Vanhecke D, Laugks U, Stein V, Fukuda Y, Schaffer M, Baumeister W, Lucic V. Pleomorphic linkers as ubiquitous structural organizers of vesicles in axons. PLoS One 2018; 13:e0197886. [PMID: 29864134 PMCID: PMC5986143 DOI: 10.1371/journal.pone.0197886] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/10/2018] [Indexed: 11/30/2022] Open
Abstract
Many cellular processes depend on a precise structural organization of molecular components. Here, we established that neurons grown in culture provide a suitable system for in situ structural investigations of cellular structures by cryo-electron tomography, a method that allows high resolution, three-dimensional imaging of fully hydrated, vitrified cellular samples. A higher level of detail of cellular components present in our images allowed us to quantitatively characterize presynaptic and cytoskeletal organization, as well as structures involved in axonal transport and endocytosis. In this way we provide a structural framework into which information from other methods need to fit. Importantly, we show that short pleomorphic linkers (tethers and connectors) extensively interconnect different types of spherical vesicles and other lipid membranes in neurons imaged in a close-to-native state. These linkers likely serve to organize and precisely position vesicles involved in endocytosis, axonal transport and synaptic release. Hence, structural interactions via short linkers may serve as ubiquitous vesicle organizers in neuronal cells.
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Affiliation(s)
- Nikolas Schrod
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Dimitri Vanhecke
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Ulrike Laugks
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Valentin Stein
- Institute of Physiology II, University of Bonn, Bonn, Germany
| | - Yoshiyuki Fukuda
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Miroslava Schaffer
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Wolfgang Baumeister
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
| | - Vladan Lucic
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
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25
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Monday HR, Younts TJ, Castillo PE. Long-Term Plasticity of Neurotransmitter Release: Emerging Mechanisms and Contributions to Brain Function and Disease. Annu Rev Neurosci 2018; 41:299-322. [PMID: 29709205 DOI: 10.1146/annurev-neuro-080317-062155] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Long-lasting changes of brain function in response to experience rely on diverse forms of activity-dependent synaptic plasticity. Chief among them are long-term potentiation and long-term depression of neurotransmitter release, which are widely expressed by excitatory and inhibitory synapses throughout the central nervous system and can dynamically regulate information flow in neural circuits. This review article explores recent advances in presynaptic long-term plasticity mechanisms and contributions to circuit function. Growing evidence indicates that presynaptic plasticity may involve structural changes, presynaptic protein synthesis, and transsynaptic signaling. Presynaptic long-term plasticity can alter the short-term dynamics of neurotransmitter release, thereby contributing to circuit computations such as novelty detection, modifications of the excitatory/inhibitory balance, and sensory adaptation. In addition, presynaptic long-term plasticity underlies forms of learning and its dysregulation participates in several neuropsychiatric conditions, including schizophrenia, autism, intellectual disabilities, neurodegenerative diseases, and drug abuse.
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Affiliation(s)
- Hannah R Monday
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
| | - Thomas J Younts
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
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Special Issue on Synapse Assembly, Neural Circuit Development, and Brain Disorders. Exp Mol Med 2018; 50:1-2. [PMID: 29628499 PMCID: PMC5938043 DOI: 10.1038/s12276-018-0049-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 11/09/2022] Open
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Maritzen T, Haucke V. Coupling of exocytosis and endocytosis at the presynaptic active zone. Neurosci Res 2018; 127:45-52. [DOI: 10.1016/j.neures.2017.09.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/13/2017] [Accepted: 08/25/2017] [Indexed: 01/08/2023]
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Ziv NE. Maintaining the active zone: Demand, supply and disposal of core active zone proteins. Neurosci Res 2018; 127:70-77. [DOI: 10.1016/j.neures.2017.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/26/2017] [Indexed: 11/29/2022]
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Liang Y, Sigrist S. Autophagy and proteostasis in the control of synapse aging and disease. Curr Opin Neurobiol 2018; 48:113-121. [DOI: 10.1016/j.conb.2017.12.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/25/2017] [Accepted: 12/10/2017] [Indexed: 11/30/2022]
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Accessibility of axonal G protein coupled mu-opioid receptors requires conceptual changes of axonal membrane targeting for pain modulation. J Control Release 2017; 268:352-363. [PMID: 29054370 DOI: 10.1016/j.jconrel.2017.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 10/07/2017] [Accepted: 10/13/2017] [Indexed: 12/19/2022]
Abstract
The mechanisms of axonal trafficking and membrane targeting are well established for sodium channels, which are the principle targets for perineurally applied local anaesthetics. However, they have not been thoroughly investigated for G protein coupled receptors such as mu-opioid receptors (MOR). Focusing on these axonal mechanisms, we found that axonal MOR functionality is quite distinct in two different pain states, i.e. hindpaw inflammation and nerve injury. We observed axonal membrane MOR binding and functional G protein coupling exclusively at sites of CCI nerve injury. Moreover at these axonal membrane sites, MOR exhibited extensive co-localization with the membrane proteins SNAP and Na/K-ATPase as well as NGF-dependent enhanced lipid rafts and L1CAM anchoring proteins. Silencing endogenous L1CAM with intrathecal L1CAM specific siRNA, disrupting lipid rafts with the perineurial cholesterol-sequestering agent MβCD, as well as suppressing NGF receptor activation with the perineurial NGF receptor inhibitor K252a abrogated MOR axonal membrane integration, functional coupling, and agonist-elicited antinociception at sites of nerve injury. These findings suggest that local conceptual changes resulting from nerve injury are required for the establishment of functional axonal membrane MOR. Axonal integration and subsequent accessibility of functionally coupled MOR are of great relevance particularly for patients suffering from severe pain due to nerve injury or tumour infiltration.
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Schaefer N, Rotermund C, Blumrich EM, Lourenco MV, Joshi P, Hegemann RU, Jamwal S, Ali N, García Romero EM, Sharma S, Ghosh S, Sinha JK, Loke H, Jain V, Lepeta K, Salamian A, Sharma M, Golpich M, Nawrotek K, Paidi RK, Shahidzadeh SM, Piermartiri T, Amini E, Pastor V, Wilson Y, Adeniyi PA, Datusalia AK, Vafadari B, Saini V, Suárez-Pozos E, Kushwah N, Fontanet P, Turner AJ. The malleable brain: plasticity of neural circuits and behavior - a review from students to students. J Neurochem 2017. [PMID: 28632905 DOI: 10.1111/jnc.14107] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
One of the most intriguing features of the brain is its ability to be malleable, allowing it to adapt continually to changes in the environment. Specific neuronal activity patterns drive long-lasting increases or decreases in the strength of synaptic connections, referred to as long-term potentiation and long-term depression, respectively. Such phenomena have been described in a variety of model organisms, which are used to study molecular, structural, and functional aspects of synaptic plasticity. This review originated from the first International Society for Neurochemistry (ISN) and Journal of Neurochemistry (JNC) Flagship School held in Alpbach, Austria (Sep 2016), and will use its curriculum and discussions as a framework to review some of the current knowledge in the field of synaptic plasticity. First, we describe the role of plasticity during development and the persistent changes of neural circuitry occurring when sensory input is altered during critical developmental stages. We then outline the signaling cascades resulting in the synthesis of new plasticity-related proteins, which ultimately enable sustained changes in synaptic strength. Going beyond the traditional understanding of synaptic plasticity conceptualized by long-term potentiation and long-term depression, we discuss system-wide modifications and recently unveiled homeostatic mechanisms, such as synaptic scaling. Finally, we describe the neural circuits and synaptic plasticity mechanisms driving associative memory and motor learning. Evidence summarized in this review provides a current view of synaptic plasticity in its various forms, offers new insights into the underlying mechanisms and behavioral relevance, and provides directions for future research in the field of synaptic plasticity. Read the Editorial Highlight for this article on page 788. Cover Image for this issue: doi: 10.1111/jnc.13815.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University of Wuerzburg, Würzburg, Germany
| | - Carola Rotermund
- German Center of Neurodegenerative Diseases, University of Tuebingen, Tuebingen, Germany
| | - Eva-Maria Blumrich
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.,Centre for Environmental Research and Sustainable Technology, University of Bremen, Bremen, Germany
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pooja Joshi
- Inserm UMR 1141, Robert Debre Hospital, Paris, France
| | - Regina U Hegemann
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Sumit Jamwal
- Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Nilufar Ali
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | | | - Sorabh Sharma
- Neuropharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Shampa Ghosh
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Jitendra K Sinha
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Hannah Loke
- Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
| | - Vishal Jain
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Katarzyna Lepeta
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Mahima Sharma
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mojtaba Golpich
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Katarzyna Nawrotek
- Department of Process Thermodynamics, Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Ramesh K Paidi
- CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India
| | - Sheila M Shahidzadeh
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Tetsade Piermartiri
- Programa de Pós-Graduação em Neurociências, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Veronica Pastor
- Instituto de Biología Celular y Neurociencia Prof. Eduardo De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yvette Wilson
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Philip A Adeniyi
- Cell Biology and Neurotoxicity Unit, Department of Anatomy, College of Medicine and Health Sciences, Afe Babalola University, Ado - Ekiti, Ekiti State, Nigeria
| | | | - Benham Vafadari
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Vedangana Saini
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Edna Suárez-Pozos
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Toxicología, México
| | - Neetu Kushwah
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Paula Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cellular Biology and Neuroscience (IBCN), CONICET-UBA, School of Medicine, Buenos Aires, Argentina
| | - Anthony J Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Wierenga CJ. Live imaging of inhibitory axons: Synapse formation as a dynamic trial-and-error process. Brain Res Bull 2016; 129:43-49. [PMID: 27720814 DOI: 10.1016/j.brainresbull.2016.09.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/20/2016] [Accepted: 09/29/2016] [Indexed: 02/07/2023]
Abstract
In this review I discuss recent live imaging studies that demonstrate that synapses, and in particular inhibitory synapses, are highly dynamic structures. The ongoing changes of presynaptic boutons within axons emphasize the stochastic aspect of inhibitory synapse formation and paint a picture of a dynamic trial-and-error process. Furthermore, I discuss recent and previous insights in the molecular and mechanistic pathways that underlie synapse formation, with a specific focus on the formation of inhibitory presynaptic boutons.
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Affiliation(s)
- Corette J Wierenga
- Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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