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Kunde SA, Schmerl B, von Sivers J, Ahmadyar E, Gupta T, Rademacher N, Zieger HL, Shoichet SA. JNK activity modulates postsynaptic scaffold protein SAP102 and kainate receptor dynamics in dendritic spines. J Biol Chem 2024; 300:107263. [PMID: 38582451 PMCID: PMC11081805 DOI: 10.1016/j.jbc.2024.107263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/08/2024] Open
Abstract
Synapse formation depends on the coordinated expression and regulation of scaffold proteins. The JNK family kinases play a role in scaffold protein regulation, but the nature of this functional interaction in dendritic spines requires further investigation. Here, using a combination of biochemical methods and live-cell imaging strategies, we show that the dynamics of the synaptic scaffold molecule SAP102 are negatively regulated by JNK inhibition, that SAP102 is a direct phosphorylation target of JNK3, and that SAP102 regulation by JNK is restricted to neurons that harbor mature synapses. We further demonstrate that SAP102 and JNK3 cooperate in the regulated trafficking of kainate receptors to the cell membrane. Specifically, we observe that SAP102, JNK3, and the kainate receptor subunit GluK2 exhibit overlapping expression at synaptic sites and that modulating JNK activity influences the surface expression of the kainate receptor subunit GluK2 in a neuronal context. We also show that SAP102 participates in this process in a JNK-dependent fashion. In summary, our data support a model in which JNK-mediated regulation of SAP102 influences the dynamic trafficking of kainate receptors to postsynaptic sites, and thus shed light on common pathophysiological mechanisms underlying the cognitive developmental defects associated with diverse mutations.
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Affiliation(s)
- Stella-Amrei Kunde
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Bettina Schmerl
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Judith von Sivers
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Elham Ahmadyar
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Taanisha Gupta
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nils Rademacher
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
| | - Hanna L Zieger
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, University of Bordeaux, Bordeaux, France
| | - Sarah A Shoichet
- Neuroscience Research Center NWFZ, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
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2
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Chato-Astrain I, Pronot M, Coppola T, Martin S. Molecular Organization and Regulation of the Mammalian Synapse by the Post-Translational Modification SUMOylation. Cells 2024; 13:420. [PMID: 38474384 DOI: 10.3390/cells13050420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Neurotransmission occurs within highly specialized compartments forming the active synapse where the complex organization and dynamics of the interactions are tightly orchestrated both in time and space. Post-translational modifications (PTMs) are central to these spatiotemporal regulations to ensure an efficient synaptic transmission. SUMOylation is a dynamic PTM that modulates the interactions between proteins and consequently regulates the conformation, the distribution and the trafficking of the SUMO-target proteins. SUMOylation plays a crucial role in synapse formation and stabilization, as well as in the regulation of synaptic transmission and plasticity. In this review, we summarize the molecular consequences of this protein modification in the structural organization and function of the mammalian synapse. We also outline novel activity-dependent regulation and consequences of the SUMO process and explore how this protein modification can functionally participate in the compartmentalization of both pre- and post-synaptic sites.
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Affiliation(s)
- Isabel Chato-Astrain
- Université Côte d'Azur, CNRS, Inserm, IPMC, Sophia Antipolis, F-06560 Valbonne, France
| | - Marie Pronot
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Thierry Coppola
- Université Côte d'Azur, CNRS, Inserm, IPMC, Sophia Antipolis, F-06560 Valbonne, France
| | - Stéphane Martin
- Université Côte d'Azur, CNRS, Inserm, IPMC, Sophia Antipolis, F-06560 Valbonne, France
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3
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Yucel BP, Al Momany EM, Evans AJ, Seager R, Wilkinson KA, Henley JM. Coordinated interplay between palmitoylation, phosphorylation and SUMOylation regulates kainate receptor surface expression. Front Mol Neurosci 2023; 16:1270849. [PMID: 37868810 PMCID: PMC10585046 DOI: 10.3389/fnmol.2023.1270849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/11/2023] [Indexed: 10/24/2023] Open
Abstract
Kainate receptors (KARs) are key regulators of neuronal excitability and synaptic transmission. KAR surface expression is tightly controlled in part by post-translational modifications (PTMs) of the GluK2 subunit. We have shown previously that agonist activation of GluK2-containing KARs leads to phosphorylation of GluK2 at S868, which promotes subsequent SUMOylation at K886 and receptor endocytosis. Furthermore, GluK2 has been shown to be palmitoylated. However, how the interplay between palmitoylation, phosphorylation and SUMOylation orchestrate KAR trafficking remains unclear. Here, we used a library of site-specific GluK2 mutants to investigate the interrelationship between GluK2 PTMs, and their impact on KAR surface expression. We show that GluK2 is basally palmitoylated and that this is decreased by kainate (KA) stimulation. Moreover, a non-palmitoylatable GluK2 mutant (C858/C871A) shows enhanced S868 phosphorylation and K886 SUMOylation under basal conditions and is insensitive to KA-induced internalisation. These results indicate that GluK2 palmitoylation contributes to stabilising KAR surface expression and that dynamic depalmitoylation promotes downstream phosphorylation and SUMOylation to mediate activity-dependent KAR endocytosis.
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Affiliation(s)
| | | | | | | | - Kevin A. Wilkinson
- Centre for Synaptic Plasticity, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - Jeremy M. Henley
- Centre for Synaptic Plasticity, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
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4
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Abstract
Neural communication and modulation are complex processes. Ionotropic glutamate receptors (iGluRs) significantly contribute to mediating the fast-excitatory branch of neurotransmission in the mammalian brain. Kainate receptors (KARs), a subfamily of the iGluRs, act as modulators of the neuronal circuitry by playing important roles at both the post- and presynaptic sites of specific neurons. The functional tetrameric receptors are formed by two different gene families, low agonist affinity (GluK1-GluK3) and high agonist affinity (GluK4-GluK5) subunits. These receptors garnered attention in the past three decades, and since then, much work has been done to understand their localization, interactome, physiological functions, and regulation. Cloning of the receptor subunits (GluK1-GluK5) in the early 1990s led to recombinant expression of kainate receptors in heterologous systems. This facilitated understanding of the functional differences between subunit combinations, splice variants, trafficking, and drug discovery. Structural studies of individual domains and recent full-length homomeric and heteromeric kainate receptors have revealed unique functional mechanisms, which have answered several long-standing questions in the field of kainate receptor biology. In this chapter, we review the current understanding of kainate receptors and associated disorders.
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Affiliation(s)
- Surbhi Dhingra
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India
| | - Juhi Yadav
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India
| | - Janesh Kumar
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India.
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5
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Surface biotinylation of primary neurons to monitor changes in AMPA receptor surface expression in response to kainate receptor stimulation. STAR Protoc 2021; 2:100992. [PMID: 34934960 DOI: 10.1016/j.xpro.2021.100992] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we detail a surface biotinylation technique used to label surface-expressed proteins in primary neuronal cultures. Surface proteins are labeled with membrane-impermeant Sulfo-NHS-SS-biotin, and isolated by pull-down with streptavidin beads followed by western blotting to measure levels of surface expression of the protein of interest under different conditions. We have used this approach extensively to monitor activity-dependent changes in α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and kainate receptor (KAR) subunits. However, this protocol can be used to investigate any surface-expressed protein. For complete details on the use and execution of this protocol, please refer to Nair et al. (2021).
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6
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Welch MA, Jansen LAR, Baro DJ. SUMOylation of the Kv4.2 Ternary Complex Increases Surface Expression and Current Amplitude by Reducing Internalization in HEK 293 Cells. Front Mol Neurosci 2021; 14:757278. [PMID: 34795560 PMCID: PMC8593141 DOI: 10.3389/fnmol.2021.757278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
Kv4 α-subunits exist as ternary complexes (TC) with potassium channel interacting proteins (KChIP) and dipeptidyl peptidase-like proteins (DPLP); multiple ancillary proteins also interact with the α-subunits throughout the channel’s lifetime. Dynamic regulation of Kv4.2 protein interactions adapts the transient potassium current, IA, mediated by Kv4 α-subunits. Small ubiquitin-like modifier (SUMO) is an 11 kD peptide post-translationally added to lysine (K) residues to regulate protein–protein interactions. We previously demonstrated that when expressed in human embryonic kidney (HEK) cells, Kv4.2 can be SUMOylated at two K residues, K437 and K579. SUMOylation at K437 increased surface expression of electrically silent channels while SUMOylation at K579 reduced IA maximal conductance (Gmax) without altering surface expression. KChIP and DPLP subunits are known to modify the pattern of Kv4.2 post-translational decorations and/or their effects. In this study, co-expressing Kv4.2 with KChIP2a and DPP10c altered the effects of enhanced Kv4.2 SUMOylation. First, the effect of enhanced SUMOylation was the same for a TC containing either the wild-type Kv4.2 or the mutant K437R Kv4.2, suggesting that either the experimental manipulation no longer enhanced K437 SUMOylation or K437 SUMOylation no longer influenced Kv4.2 surface expression. Second, instead of decreasing IA Gmax, enhanced SUMOylation at K579 now produced a significant ∼37–70% increase in IA maximum conductance (Gmax) and a significant ∼30–50% increase in Kv4.2g surface expression that was accompanied by a 65% reduction in TC internalization. Blocking clathrin-mediated endocytosis (CME) in HEK cells expressing the Kv4.2 TC mimicked and occluded the effect of SUMO on IA Gmax; however, the amount of Kv4.2 associated with the major adaptor for constitutive CME, adaptor protein 2 (AP2), was not SUMO dependent. Thus, SUMOylation reduced Kv4.2 internalization by acting downstream of Kv4.2 recruitment into clathrin-coated pits. In sum, the two major findings of this study are: SUMOylation of Kv4.2 at K579 regulates TC internalization most likely by promoting channel recycling. Additionally, there is a reciprocity between Kv4.2 SUMOylation and the Kv4.2 interactome such that SUMOylation regulates the interactome and the interactome influences the pattern and effect of SUMOylation.
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Affiliation(s)
- Meghyn A Welch
- Department of Biology, Georgia State University, Atlanta, GA, United States
| | | | - Deborah J Baro
- Department of Biology, Georgia State University, Atlanta, GA, United States.,Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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7
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Yang Q, Liu J, Wang Z. 4.1N-Mediated Interactions and Functions in Nerve System and Cancer. Front Mol Biosci 2021; 8:711302. [PMID: 34589518 PMCID: PMC8473747 DOI: 10.3389/fmolb.2021.711302] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/16/2021] [Indexed: 01/05/2023] Open
Abstract
Scaffolding protein 4.1N is a neuron-enriched 4.1 homologue. 4.1N contains three conserved domains, including the N-terminal 4.1-ezrin-radixin-moesin (FERM) domain, internal spectrin–actin–binding (SAB) domain, and C-terminal domain (CTD). Interspersed between the three domains are nonconserved domains, including U1, U2, and U3. The role of 4.1N was first reported in the nerve system. Then, extensive studies reported the role of 4.1N in cancers and other diseases. 4.1N performs numerous vital functions in signaling transduction by interacting, locating, supporting, and coordinating different partners and is involved in the molecular pathogenesis of various diseases. In this review, recent studies on the interactions between 4.1N and its contactors (including the α7AChr, IP3R1, GluR1/4, GluK1/2/3, mGluR8, KCC2, D2/3Rs, CASK, NuMA, PIKE, IP6K2, CAM 1/3, βII spectrin, flotillin-1, pp1, and 14-3-3) and the 4.1N-related biological functions in the nerve system and cancers are specifically and comprehensively discussed. This review provides critical detailed mechanistic insights into the role of 4.1N in disease relationships.
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Affiliation(s)
- Qin Yang
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,School of Medical Laboratory, Shao Yang University, Shaoyang, China
| | - Jing Liu
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zi Wang
- Molecular Biology Research Center & Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
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8
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Nair JD, Braksator E, Yucel BP, Fletcher-Jones A, Seager R, Mellor JR, Bashir ZI, Wilkinson KA, Henley JM. Sustained postsynaptic kainate receptor activation downregulates AMPA receptor surface expression and induces hippocampal LTD. iScience 2021; 24:103029. [PMID: 34553130 PMCID: PMC8441151 DOI: 10.1016/j.isci.2021.103029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 07/27/2021] [Accepted: 08/20/2021] [Indexed: 01/21/2023] Open
Abstract
It is well established that long-term depression (LTD) can be initiated by either NMDA or mGluR activation. Here we report that sustained activation of GluK2 subunit-containing kainate receptors (KARs) leads to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) endocytosis and induces LTD of AMPARs (KAR-LTDAMPAR) in hippocampal neurons. The KAR-evoked loss of surface AMPARs is blocked by the ionotropic KAR inhibitor UBP 310 indicating that KAR-LTDAMPAR requires KAR channel activity. Interestingly, however, blockade of PKC or PKA also reduces GluA2 surface expression and occludes the effect of KAR activation. In acute hippocampal slices, kainate application caused a significant loss of GluA2-containing AMPARs from synapses and long-lasting depression of AMPAR excitatory postsynaptic currents in CA1. These data, together with our previously reported KAR-LTPAMPAR, demonstrate that KARs can bidirectionally regulate synaptic AMPARs and synaptic plasticity via different signaling pathways.
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Affiliation(s)
- Jithin D Nair
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Ellen Braksator
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Busra P Yucel
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Alexandra Fletcher-Jones
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Richard Seager
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Zafar I Bashir
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kevin A Wilkinson
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jeremy M Henley
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK.,Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
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9
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Nair JD, Wilkinson KA, Henley JM, Mellor JR. Kainate receptors and synaptic plasticity. Neuropharmacology 2021; 196:108540. [PMID: 33794245 DOI: 10.1016/j.neuropharm.2021.108540] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 10/21/2022]
Abstract
Synaptic plasticity has classically been characterized to involve the NMDA and AMPA subtypes of glutamate receptors, with NMDA receptors providing the key trigger for the induction of long-term plasticity leading to changes in AMPA receptor expression. Here we review the more subtle roles played by kainate receptors, which contribute critical postsynaptic signalling as well as playing major presynaptic auto-receptor roles. We focus on two research areas: plasticity of kainate receptors themselves and the contribution they make to the plasticity of synaptic transmission. This article is part of the special issue on Glutamate Receptors - Kainate receptors.
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Affiliation(s)
- Jithin D Nair
- Center for Synaptic Plasticity, School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Kevin A Wilkinson
- Center for Synaptic Plasticity, School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Jeremy M Henley
- Center for Synaptic Plasticity, School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Jack R Mellor
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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10
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Henley JM, Nair JD, Seager R, Yucel BP, Woodhall G, Henley BS, Talandyte K, Needs HI, Wilkinson KA. Kainate and AMPA receptors in epilepsy: Cell biology, signalling pathways and possible crosstalk. Neuropharmacology 2021; 195:108569. [PMID: 33915142 DOI: 10.1016/j.neuropharm.2021.108569] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/13/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023]
Abstract
Epilepsy is caused when rhythmic neuronal network activity escapes normal control mechanisms, resulting in seizures. There is an extensive and growing body of evidence that the onset and maintenance of epilepsy involves alterations in the trafficking, synaptic surface expression and signalling of kainate and AMPA receptors (KARs and AMPARs). The KAR subunit GluK2 and AMPAR subunit GluA2 are key determinants of the properties of their respective assembled receptors. Both subunits are subject to extensive protein interactions, RNA editing and post-translational modifications. In this review we focus on the cell biology of GluK2-containing KARs and GluA2-containing AMPARs and outline how their regulation and dysregulation is implicated in, and affected by, seizure activity. Further, we discuss role of KARs in regulating AMPAR surface expression and plasticity, and the relevance of this to epilepsy. This article is part of the special issue on 'Glutamate Receptors - Kainate receptors'.
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Affiliation(s)
- Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK; Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia.
| | - Jithin D Nair
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Richard Seager
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Busra P Yucel
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Gavin Woodhall
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Benjamin S Henley
- Faculty of Medical Sciences, The Medical School, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Karolina Talandyte
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Hope I Needs
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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11
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Hwang Y, Kim HC, Shin EJ. Repeated exposure to microcystin-leucine-arginine potentiates excitotoxicity induced by a low dose of kainate. Toxicology 2021; 460:152887. [PMID: 34352349 DOI: 10.1016/j.tox.2021.152887] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/15/2021] [Accepted: 07/30/2021] [Indexed: 02/08/2023]
Abstract
Microcystin-leucine-arginine (MLCR) is a cyanobacterial toxin, and has been demonstrated to cause neurotoxicity. In addition, MCLR has been identified as an inhibitor of protein phosphatase (PP)1 and PP2A, which are known to regulate the phosphorylation of various molecules related to synaptic excitability. Thus, in the present study, we examined whether MCLR exposure affects seizures induced by a low dose of kainic acid (KA; 0.05 μg, i.c.v.) administration. KA-induced seizure occurrence and seizure score significantly increased after repeated exposure to MCLR (2.5 or 5.0 μg/kg, i.p., once a day for 10 days), but not after acute MCLR exposure (2.5 or 5.0 μg/kg, i.p., 2 h and 30 min prior to KA administration), and hippocampal neuronal loss was consistently facilitated by repeated exposure to MCLR. In addition, repeated MCLR significantly elevated the membrane expression of kainate receptor GluK2 subunits, p-pan-protein kinase C (PKC), and p-extracellular signal-related kinase (ERK) at 1 h after KA. However, KA-induced membrane expression of Ca2+/calmodulin-dependent kinase II (CaMKII) was significantly reduced by repeated MCLR exposure. Consistent with the enhanced seizures and neurodegeneration, MCLR exposure significantly potentiated KA-induced oxidative stress and microglial activation, which was accompanied by increased expression of p-ERK and p-PKCδ in the hippocampus. The combined results suggest that repeated MCLR exposure potentiates KA-induced excitotoxicity in the hippocampus by increasing membrane GluK2 expression and enhancing oxidative stress and neuroinflammation through the modulation of p-CaMKII, p-PKC, and p-ERK.
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Affiliation(s)
- Yeonggwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon, 24341, Republic of Korea.
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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12
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A disease-causing mutation K240E disrupts ferroportin trafficking by SUMO (ferroportin SUMOylation). Biochem Biophys Rep 2021; 25:100873. [PMID: 33490642 PMCID: PMC7809393 DOI: 10.1016/j.bbrep.2020.100873] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 10/20/2020] [Accepted: 12/10/2020] [Indexed: 01/01/2023] Open
Abstract
Ferroportin (Fpn/IREG1/MTP1) is the only known transporter mediating iron efflux from epithelial cells and macrophages, and thus regulates how much iron is released into the circulation. Consequently, Fpn mutations are associated with haemochromatosis. Fpn itself is post-translationally regulated by hepcidin (Hepc) which induces its redistribution and degradation in a ubiquitin-dependent process. Together, the two proteins appear to be the nexus for iron homeostasis. Here we show that a rare gain-of-function mutation (K240E) that is associated with iron overload, impedes Fpn binding and subcellular trafficking by the small ubiquitin-like modifier (SUMO). Whereas wild-type Fpn is ensconced within vesicular bodies, the FpnK240E mutant appeared diffused within the cell when co-expressed with SUMO. Furthermore, compared with wild type Fpn, the sumoylation-defective mutant was constitutively-active, resulting in a lower intracellular labile iron pool than the former. These findings suggest that SUMO may regulate iron homeostasis by controlling Fpn trafficking. Ferroportin (Fpn) regulates iron efflux. A disease causing mutation (K240E) in a patient causes iron-overload. Fpn K240 is a SUMO conjugation site important for Fpn trafficking to endosomes by SUMO. The Fpn mutant K240E cannot be trafficked properly by SUMO and is a gain-of-function mutant that is constitutively active. FpnK240E effluxes more iron from intracellular stores than wild type Fpn.
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13
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Henley JM, Seager R, Nakamura Y, Talandyte K, Nair J, Wilkinson KA. SUMOylation of synaptic and synapse-associated proteins: An update. J Neurochem 2021; 156:145-161. [PMID: 32538470 PMCID: PMC8218484 DOI: 10.1111/jnc.15103] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/13/2022]
Abstract
SUMOylation is a post-translational modification that regulates protein signalling and complex formation by adjusting the conformation or protein-protein interactions of the substrate protein. There is a compelling and rapidly expanding body of evidence that, in addition to SUMOylation of nuclear proteins, SUMOylation of extranuclear proteins contributes to the control of neuronal development, neuronal stress responses and synaptic transmission and plasticity. In this brief review we provide an update of recent developments in the identification of synaptic and synapse-associated SUMO target proteins and discuss the cell biological and functional implications of these discoveries.
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Affiliation(s)
- Jeremy M. Henley
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
| | - Richard Seager
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
| | - Yasuko Nakamura
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
| | - Karolina Talandyte
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
| | - Jithin Nair
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
| | - Kevin A. Wilkinson
- School of BiochemistryCentre for Synaptic PlasticityUniversity of BristolUniversity WalkBristolUK
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14
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Folci A, Mirabella F, Fossati M. Ubiquitin and Ubiquitin-Like Proteins in the Critical Equilibrium between Synapse Physiology and Intellectual Disability. eNeuro 2020; 7:ENEURO.0137-20.2020. [PMID: 32719102 PMCID: PMC7544190 DOI: 10.1523/eneuro.0137-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/08/2020] [Accepted: 06/17/2020] [Indexed: 01/04/2023] Open
Abstract
Posttranslational modifications (PTMs) represent a dynamic regulatory system that precisely modulates the functional organization of synapses. PTMs consist in target modifications by small chemical moieties or conjugation of lipids, sugars or polypeptides. Among them, ubiquitin and a large family of ubiquitin-like proteins (UBLs) share several features such as the structure of the small protein modifiers, the enzymatic cascades mediating the conjugation process, and the targeted aminoacidic residue. In the brain, ubiquitination and two UBLs, namely sumoylation and the recently discovered neddylation orchestrate fundamental processes including synapse formation, maturation and plasticity, and their alteration is thought to contribute to the development of neurological disorders. Remarkably, emerging evidence suggests that these pathways tightly interplay to modulate the function of several proteins that possess pivotal roles for brain homeostasis as well as failure of this crosstalk seems to be implicated in the development of brain pathologies. In this review, we outline the role of ubiquitination, sumoylation, neddylation, and their functional interplay in synapse physiology and discuss their implication in the molecular pathogenesis of intellectual disability (ID), a neurodevelopmental disorder that is frequently comorbid with a wide spectrum of brain pathologies. Finally, we propose a few outlooks that might contribute to better understand the complexity of these regulatory systems in regard to neuronal circuit pathophysiology.
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Affiliation(s)
- Alessandra Folci
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano (MI), Italy
| | - Filippo Mirabella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve 9 Emanuele - Milan, Italy
| | - Matteo Fossati
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano (MI), Italy
- CNR-Institute of Neuroscience, via Manzoni 56, 20089, Rozzano (MI), Italy
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15
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Davey JS, Carmichael RE, Craig TJ. Protein SUMOylation regulates insulin secretion at multiple stages. Sci Rep 2019; 9:2895. [PMID: 30814610 PMCID: PMC6393506 DOI: 10.1038/s41598-019-39681-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 01/21/2019] [Indexed: 01/24/2023] Open
Abstract
Type-II Diabetes Mellitus (T2DM) is one of the fastest growing public health issues of modern times, consuming 12% of worldwide health budgets and affecting an estimated 400 million people. A key pathological trait associated with this disease is the failure of normal glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells. Several lines of evidence suggest that vesicle trafficking events such as insulin secretion are regulated by the post-translational modification, SUMOylation, and indeed SUMOylation has been proposed to act as a ‘brake’ on insulin exocytosis. Here, we show that diabetic stimuli which inhibit GSIS are correlated with an increase in cellular protein SUMOylation, and that inhibition of deSUMOylation reduces GSIS. We demonstrate that manipulation of cellular protein SUMOylation levels, by overexpression of several different components of the SUMOylation pathway, have varied and complex effects on GSIS, indicating that SUMOylation regulates this process at multiple stages. We further demonstrate that inhibition of syntaxin1A SUMOylation, via a knockdown-rescue strategy, greatly enhances GSIS. Our data are therefore consistent with the model that SUMOylation acts as a brake on GSIS, and we have identified SUMOylation of syntaxin 1 A as a potential component of this brake. However, our data also demonstrate that the role of SUMOylation in GSIS is complex and may involve many substrates.
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Affiliation(s)
- Jeffrey S Davey
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol, BS16 1QY, UK
| | - Ruth E Carmichael
- College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Tim J Craig
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol, BS16 1QY, UK.
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16
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Sorting nexin 27 rescues neuroligin 2 from lysosomal degradation to control inhibitory synapse number. Biochem J 2019; 476:293-306. [PMID: 30602588 DOI: 10.1042/bcj20180504] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 01/14/2023]
Abstract
Retromer is an evolutionarily conserved endosomal trafficking complex that mediates the retrieval of cargo proteins from a degradative pathway for sorting back to the cell surface. To promote cargo recycling, the core retromer trimer of VPS (vacuolar protein sorting)26, VPS29 and VPS35 recognises cargo either directly, or through an adaptor protein, the most well characterised of which is the PDZ [postsynaptic density 95 (PSD95), disk large, zona occludens] domain-containing sorting nexin SNX27. Neuroligins (NLGs) are postsynaptic trans-synaptic scaffold proteins that function in the clustering of postsynaptic proteins to maintain synaptic stability. Here, we show that each of the NLGs (NLG1-3) bind to SNX27 in a direct PDZ ligand-dependent manner. Depletion of SNX27 from neurons leads to a decrease in levels of each NLG protein and, for NLG2, this occurs as a result of enhanced lysosomal degradation. Notably, while depletion of the core retromer component VPS35 leads to a decrease in NLG1 and NLG3 levels, NLG2 is unaffected, suggesting that, for this cargo, SNX27 acts independently of retromer. Consistent with loss of SNX27 leading to enhanced lysosomal degradation of NLG2, knockdown of SNX27 results in fewer NLG2 clusters in cultured neurons, and loss of SNX27 or VPS35 reduces the size and number of gephyrin clusters. Together, these data indicate that NLGs are SNX27-retromer cargoes and suggest that SNX27-retromer controls inhibitory synapse number, at least in part through trafficking of NLG2.
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17
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Daniel JA, Cooper BH, Palvimo JJ, Zhang FP, Brose N, Tirard M. Response: Commentary: Analysis of SUMO1-conjugation at synapses. Front Cell Neurosci 2018; 12:117. [PMID: 29766991 PMCID: PMC5938361 DOI: 10.3389/fncel.2018.00117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/12/2018] [Indexed: 01/06/2023] Open
Affiliation(s)
- James A Daniel
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jorma J Palvimo
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Fu-Ping Zhang
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Marilyn Tirard
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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18
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Abstract
Post-translational modification of substrate proteins by SUMO conjugation regulates a diverse array of cellular processes. While predominantly a nuclear protein modification, there is a growing appreciation that SUMOylation of proteins outside the nucleus plays direct roles in controlling synaptic transmission, neuronal excitability, and adaptive responses to cell stress. Furthermore, alterations in protein SUMOylation are observed in a wide range of neurological and neurodegenerative diseases, and several extranuclear disease-associated proteins have been shown to be directly SUMOylated. Here, focusing mainly on SUMOylation of synaptic and mitochondrial proteins, we outline recent developments and discoveries, and present our opinion as to the most exciting avenues for future research to define how SUMOylation of extranuclear proteins regulates neuronal and synaptic function.
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Affiliation(s)
- Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
| | - Ruth E Carmichael
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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19
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Exciting Times: New Advances Towards Understanding the Regulation and Roles of Kainate Receptors. Neurochem Res 2017; 44:572-584. [PMID: 29270706 PMCID: PMC6420428 DOI: 10.1007/s11064-017-2450-2] [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: 08/23/2017] [Revised: 11/27/2017] [Accepted: 12/07/2017] [Indexed: 12/11/2022]
Abstract
Kainate receptors (KARs) are glutamate-gated ion channels that play fundamental roles in regulating neuronal excitability and network function in the brain. After being cloned in the 1990s, important progress has been made in understanding the mechanisms controlling the molecular and cellular properties of KARs, and the nature and extent of their regulation of wider neuronal activity. However, there have been significant recent advances towards understanding KAR trafficking through the secretory pathway, their precise synaptic positioning, and their roles in synaptic plasticity and disease. Here we provide an overview highlighting these new findings about the mechanisms controlling KARs and how KARs, in turn, regulate other proteins and pathways to influence synaptic function.
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20
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Li X, Wang Y, Zhu A, Zhou J, Li Y. PKC SUMOylation inhibits the binding of 14-3-3τ to GluK2. Channels (Austin) 2017; 11:616-623. [PMID: 28837400 PMCID: PMC5786187 DOI: 10.1080/19336950.2017.1370525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 08/18/2017] [Indexed: 10/19/2022] Open
Abstract
Phosphorylation and SUMOylation of the kainate receptor (KAR) subunit GluK2 have been shown to regulate KAR surface expression, trafficking and synaptic plasticity. In addition, our previous study has shown that a phosphorylation-dependent interaction of 14-3-3τ and GluK2a-containing receptors contributes to the slow decay kinetics of native KAR-EPSCs. However, it is unknown whether SUMOylation participates in the regulation of the interaction between 14-3-3τ and GluK2a-containing receptors. Here we report that SUMOylation of PKC, but not GluK2, represses the binding of 14-3-3τ to GluK2a via decreasing the phosphorylation level of GluK2a. These results suggest that PKC SUMOylation is an important regulator of the 14-3-3 and GluK2a protein complex and may contribute to regulate the decay kinetics of KAR-EPSCs.
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Affiliation(s)
- Xiaoling Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Pharmacy, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Anesthesiology and Pain Research Center, Department of Anesthesiology, Shanghai First People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Aoxue Zhu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie Zhou
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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21
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Wilkinson KA, Martin S, Tyagarajan SK, Arancio O, Craig TJ, Guo C, Fraser PE, Goldstein SAN, Henley JM. Commentary: Analysis of SUMO1-conjugation at synapses. Front Cell Neurosci 2017; 11:345. [PMID: 29163056 PMCID: PMC5670122 DOI: 10.3389/fncel.2017.00345] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 10/16/2017] [Indexed: 11/25/2022] Open
Affiliation(s)
- Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, University of Bristol, Bristol, United Kingdom
| | - Stéphane Martin
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, IPMC, Université Côte d'Azur, Nice, France
| | - Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Ottavio Arancio
- Taub Institute and Department of Pathology and Cell Biology, Columbia University, New York, NY, United States
| | - Tim J Craig
- Department of Applied Sciences, University of the West of England, Bristol, United Kingdom
| | - Chun Guo
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | | | - Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, University of Bristol, Bristol, United Kingdom
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22
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Carmichael RE, Henley JM. Transcriptional and post-translational regulation of Arc in synaptic plasticity. Semin Cell Dev Biol 2017; 77:3-9. [PMID: 28890422 DOI: 10.1016/j.semcdb.2017.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/21/2017] [Accepted: 09/06/2017] [Indexed: 12/18/2022]
Abstract
One of the most interesting features of Arc-dependent synaptic plasticity is how multiple types of synaptic activity can converge to alter Arc transcription and then diverge to induce different plasticity outcomes, ranging from AMPA receptor internalisation that promotes long-term depression (LTD), to actin stabilisation that promotes long-term potentiation (LTP). This diversity suggests that there must be numerous levels of control to ensure the temporal profile, abundance, localisation and function of Arc are appropriately regulated to effect learning and memory in the correct contexts. The activity-dependent transcription and post-translational modification of Arc are crucial regulators of synaptic plasticity, fine-tuning the function of this key protein depending on the specific situation. The extensive cross-talk between signalling pathways and the numerous routes of Arc regulation provide a complex interplay of processes in which Arc-mediated plasticity can be broadly induced, but specifically tailored to synaptic activity. Here we provide an overview what is currently known about these processes and potential future directions.
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Affiliation(s)
- Ruth E Carmichael
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Jeremy M Henley
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom.
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23
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SUMOylation and calcium signalling: potential roles in the brain and beyond. Neuronal Signal 2017; 1:NS20160010. [PMID: 32714579 PMCID: PMC7373246 DOI: 10.1042/ns20160010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 12/23/2022] Open
Abstract
Small ubiquitin-like modifier (SUMO) conjugation (or SUMOylation) is a post-translational protein modification implicated in alterations to protein expression, localization and function. Despite a number of nuclear roles for SUMO being well characterized, this process has only started to be explored in relation to membrane proteins, such as ion channels. Calcium ion (Ca2+) signalling is crucial for the normal functioning of cells and is also involved in the pathophysiological mechanisms underlying relevant neurological and cardiovascular diseases. Intracellular Ca2+ levels are tightly regulated; at rest, most Ca2+ is retained in organelles, such as the sarcoplasmic reticulum, or in the extracellular space, whereas depolarization triggers a series of events leading to Ca2+ entry, followed by extrusion and reuptake. The mechanisms that maintain Ca2+ homoeostasis are candidates for modulation at the post-translational level. Here, we review the effects of protein SUMOylation, including Ca2+ channels, their proteome and other proteins associated with Ca2+ signalling, on vital cellular functions, such as neurotransmission within the central nervous system (CNS) and in additional systems, most prominently here, in the cardiac system.
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24
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Evans AJ, Gurung S, Wilkinson KA, Stephens DJ, Henley JM. Assembly, Secretory Pathway Trafficking, and Surface Delivery of Kainate Receptors Is Regulated by Neuronal Activity. Cell Rep 2017; 19:2613-2626. [PMID: 28636947 PMCID: PMC5489663 DOI: 10.1016/j.celrep.2017.06.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/17/2017] [Accepted: 05/25/2017] [Indexed: 01/03/2023] Open
Abstract
Ionotropic glutamate receptor (iGluR) trafficking and function underpin excitatory synaptic transmission and plasticity and shape neuronal networks. It is well established that the transcription, translation, and endocytosis/recycling of iGluRs are all regulated by neuronal activity, but much less is known about the activity dependence of iGluR transport through the secretory pathway. Here, we use the kainate receptor subunit GluK2 as a model iGluR cargo to show that the assembly, early secretory pathway trafficking, and surface delivery of iGluRs are all controlled by neuronal activity. We show that the delivery of de novo kainate receptors is differentially regulated by modulation of GluK2 Q/R editing, PKC phosphorylation, and PDZ ligand interactions. These findings reveal that, in addition to short-term regulation of iGluRs by recycling/endocytosis and long-term modulation by altered transcription/translation, the trafficking of iGluRs through the secretory pathway is under tight activity-dependent control to determine the numbers and properties of surface-expressed iGluRs.
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Affiliation(s)
- Ashley J Evans
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Sonam Gurung
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - David J Stephens
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK.
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25
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Daniel JA, Cooper BH, Palvimo JJ, Zhang FP, Brose N, Tirard M. Analysis of SUMO1-conjugation at synapses. eLife 2017; 6. [PMID: 28598330 PMCID: PMC5493437 DOI: 10.7554/elife.26338] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/07/2017] [Indexed: 12/14/2022] Open
Abstract
SUMO1-conjugation of proteins at neuronal synapses is considered to be a major post-translational regulatory process in nerve cell and synapse function, but the published evidence for SUMO1-conjugation at synapses is contradictory. We employed multiple genetic mouse models for stringently controlled biochemical and immunostaining analyses of synaptic SUMO1-conjugation. By using a knock-in reporter mouse line expressing tagged SUMO1, we could not detect SUMO1-conjugation of seven previously proposed synaptic SUMO1-targets in the brain. Further, immunostaining of cultured neurons from wild-type and SUMO1 knock-out mice showed that anti-SUMO1 immunolabelling at synapses is non-specific. Our findings indicate that SUMO1-conjugation of synaptic proteins does not occur or is extremely rare and hence not detectable using current methodology. Based on our data, we discuss a set of experimental strategies and minimal consensus criteria for the validation of SUMOylation that can be applied to any SUMOylation substrate and SUMO isoform. DOI:http://dx.doi.org/10.7554/eLife.26338.001
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Affiliation(s)
- James A Daniel
- Max Planck Institute of Experimental Medicine, Molecular Neurobiology, Göttingen, Germany
| | - Benjamin H Cooper
- Max Planck Institute of Experimental Medicine, Molecular Neurobiology, Göttingen, Germany
| | - Jorma J Palvimo
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Fu-Ping Zhang
- Institute of Biomedicine and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Nils Brose
- Max Planck Institute of Experimental Medicine, Molecular Neurobiology, Göttingen, Germany
| | - Marilyn Tirard
- Max Planck Institute of Experimental Medicine, Molecular Neurobiology, Göttingen, Germany
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26
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Pressey JC, Mahadevan V, Khademullah CS, Dargaei Z, Chevrier J, Ye W, Huang M, Chauhan AK, Meas SJ, Uvarov P, Airaksinen MS, Woodin MA. A kainate receptor subunit promotes the recycling of the neuron-specific K +-Cl - co-transporter KCC2 in hippocampal neurons. J Biol Chem 2017; 292:6190-6201. [PMID: 28235805 PMCID: PMC5391750 DOI: 10.1074/jbc.m116.767236] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/24/2017] [Indexed: 11/06/2022] Open
Abstract
Synaptic inhibition depends on a transmembrane gradient of chloride, which is set by the neuron-specific K+-Cl- co-transporter KCC2. Reduced KCC2 levels in the neuronal membrane contribute to the generation of epilepsy, neuropathic pain, and autism spectrum disorders; thus, it is important to characterize the mechanisms regulating KCC2 expression. In the present study, we determined the role of KCC2-protein interactions in regulating total and surface membrane KCC2 expression. Using quantitative immunofluorescence in cultured mouse hippocampal neurons, we discovered that the kainate receptor subunit GluK2 and the auxiliary subunit Neto2 significantly increase the total KCC2 abundance in neurons but that GluK2 exclusively increases the abundance of KCC2 in the surface membrane. Using a live cell imaging assay, we further determined that KCC2 recycling primarily occurs within 1-2 h and that GluK2 produces an ∼40% increase in the amount of KCC2 recycled to the membrane during this time period. This GluK2-mediated increase in surface recycling translated to a significant increase in KCC2 expression in the surface membrane. Moreover, we found that KCC2 recycling is enhanced by protein kinase C-mediated phosphorylation of the GluK2 C-terminal residues Ser-846 and Ser-868. Lastly, using gramicidin-perforated patch clamp recordings, we found that the GluK2-mediated increase in KCC2 recycling to the surface membrane translates to a hyperpolarization of the reversal potential for GABA (EGABA). In conclusion, our results have revealed a mechanism by which kainate receptors regulate KCC2 expression in the hippocampus.
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Affiliation(s)
- Jessica C Pressey
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Vivek Mahadevan
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - C Sahara Khademullah
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Zahra Dargaei
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Jonah Chevrier
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Wenqing Ye
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Michelle Huang
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Alamjeet K Chauhan
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Steven J Meas
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
| | - Pavel Uvarov
- the Department of Anatomy, University of Helsinki, 00014 Helsinki, Finland
| | - Matti S Airaksinen
- the Department of Anatomy, University of Helsinki, 00014 Helsinki, Finland
| | - Melanie A Woodin
- From the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada and
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27
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Dustrude ET, Perez-Miller S, François-Moutal L, Moutal A, Khanna M, Khanna R. A single structurally conserved SUMOylation site in CRMP2 controls NaV1.7 function. Channels (Austin) 2017; 11:316-328. [PMID: 28277940 DOI: 10.1080/19336950.2017.1299838] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The neuronal collapsin response mediator protein 2 (CRMP2) undergoes several posttranslational modifications that codify its functions. Most recently, CRMP2 SUMOylation (addition of small ubiquitin like modifier (SUMO)) was identified as a key regulatory step within a modification program that codes for CRMP2 interaction with, and trafficking of, voltage-gated sodium channel NaV1.7. In this paper, we illustrate the utility of combining sequence alignment within protein families with structural analysis to identify, from several putative SUMOylation sites, those that are most likely to be biologically relevant. Co-opting this principle to CRMP2, we demonstrate that, of 3 sites predicted to be SUMOylated in CRMP2, only the lysine 374 site is a SUMOylation client. A reduction in NaV1.7 currents was the corollary of the loss of CRMP2 SUMOylation at this site. A 1.78-Å-resolution crystal structure of mouse CRMP2 was solved using X-ray crystallography, revealing lysine 374 as buried within the CRMP2 tetramer interface but exposed in the monomer. Since CRMP2 SUMOylation is dependent on phosphorylation, we postulate that this state forces CRMP2 toward a monomer, exposing the SUMO site and consequently, resulting in constitutive regulation of NaV1.7.
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Affiliation(s)
- Erik Thomas Dustrude
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA
| | - Samantha Perez-Miller
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA
| | - Liberty François-Moutal
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA
| | - Aubin Moutal
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA
| | - May Khanna
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA
| | - Rajesh Khanna
- a Department of Pharmacology, College of Medicine , University of Arizona , Tucson , AZ , USA.,b Department of Anesthesiology, College of Medicine , University of Arizona , Tucson , AZ , USA.,c Neuroscience Graduate Interdisciplinary Program, College of Medicine , University of Arizona , Tucson , AZ , USA
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Parker AR, Welch MA, Forster LA, Tasneem SM, Dubhashi JA, Baro DJ. SUMOylation of the Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 2 Increases Surface Expression and the Maximal Conductance of the Hyperpolarization-Activated Current. Front Mol Neurosci 2017; 9:168. [PMID: 28127275 PMCID: PMC5226956 DOI: 10.3389/fnmol.2016.00168] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 12/26/2016] [Indexed: 11/13/2022] Open
Abstract
Small Ubiquitin-like Modifier (SUMO) is a ∼10 kDa peptide that can be post-translationally added to a lysine (K) on a target protein to facilitate protein–protein interactions. Recent studies have found that SUMOylation can be regulated in an activity-dependent manner and that ion channel SUMOylation can alter the biophysical properties and surface expression of the channel. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel surface expression can be regulated in an activity-dependent manner through unknown processes. We hypothesized that SUMOylation might influence the surface expression of HCN2 channels. In this manuscript, we show that HCN2 channels are SUMOylated in the mouse brain. Baseline levels of SUMOylation were also observed for a GFP-tagged HCN2 channel stably expressed in Human embryonic kidney (Hek) cells. Elevating GFP-HCN2 channel SUMOylation above baseline in Hek cells led to an increase in surface expression that augmented the hyperpolarization-activated current (Ih) mediated by these channels. Increased SUMOylation did not alter Ih voltage-dependence or kinetics of activation. There are five predicted intracellular SUMOylation sites on HCN2. Site-directed mutagenesis indicated that more than one K on the GFP-HCN2 channel was SUMOylated. Enhancing SUMOylation at one of the five predicted sites, K669, led to the increase in surface expression and IhGmax. The role of SUMOylation at additional sites is currently unknown. The SUMOylation site at K669 is also conserved in HCN1 channels. Aberrant SUMOylation has been linked to neurological diseases that also display alterations in HCN1 and HCN2 channel expression, such as seizures and Parkinson’s disease. This work is the first report that HCN channels can be SUMOylated and that this can regulate surface expression and Ih.
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Affiliation(s)
- Anna R Parker
- Department of Biology, Georgia State University Atlanta, GA, USA
| | - Meghyn A Welch
- Department of Biology, Georgia State University Atlanta, GA, USA
| | - Lori A Forster
- Neuroscience Institute, Georgia State University Atlanta, GA, USA
| | - Sarah M Tasneem
- Department of Biology, Georgia State University Atlanta, GA, USA
| | | | - Deborah J Baro
- Department of Biology, Georgia State UniversityAtlanta, GA, USA; Neuroscience Institute, Georgia State UniversityAtlanta, GA, USA
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29
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Plant LD, Marks JD, Goldstein SAN. SUMOylation of Na V1.2 channels mediates the early response to acute hypoxia in central neurons. eLife 2016; 5:e20054. [PMID: 28029095 PMCID: PMC5283832 DOI: 10.7554/elife.20054] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/27/2016] [Indexed: 12/02/2022] Open
Abstract
The mechanism for the earliest response of central neurons to hypoxia-an increase in voltage-gated sodium current (INa)-has been unknown. Here, we show that hypoxia activates the Small Ubiquitin-like Modifier (SUMO) pathway in rat cerebellar granule neurons (CGN) and that SUMOylation of NaV1.2 channels increases INa. The time-course for SUMOylation of single NaV1.2 channels at the cell surface and changes in INa coincide, and both are prevented by mutation of NaV1.2-Lys38 or application of a deSUMOylating enzyme. Within 40 s, hypoxia-induced linkage of SUMO1 to the channels is complete, shifting the voltage-dependence of channel activation so that depolarizing steps evoke larger sodium currents. Given the recognized role of INa in hypoxic brain damage, the SUMO pathway and NaV1.2 are identified as potential targets for neuroprotective interventions.
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Affiliation(s)
- Leigh D Plant
- Department of Biochemistry, Brandeis University, Waltham, United States
| | - Jeremy D Marks
- Department of Pediatrics, University of Chicago, Chicago, United States
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30
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Ghosh H, Auguadri L, Battaglia S, Simone Thirouin Z, Zemoura K, Messner S, Acuña MA, Wildner H, Yévenes GE, Dieter A, Kawasaki H, O Hottiger M, Zeilhofer HU, Fritschy JM, Tyagarajan SK. Several posttranslational modifications act in concert to regulate gephyrin scaffolding and GABAergic transmission. Nat Commun 2016; 7:13365. [PMID: 27819299 PMCID: PMC5103071 DOI: 10.1038/ncomms13365] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 09/26/2016] [Indexed: 11/18/2022] Open
Abstract
GABAA receptors (GABAARs) mediate the majority of fast inhibitory neurotransmission in the brain via synergistic association with the postsynaptic scaffolding protein gephyrin and its interaction partners. However, unlike their counterparts at glutamatergic synapses, gephyrin and its binding partners lack canonical protein interaction motifs; hence, the molecular basis for gephyrin scaffolding has remained unclear. In this study, we identify and characterize two new posttranslational modifications of gephyrin, SUMOylation and acetylation. We demonstrate that crosstalk between SUMOylation, acetylation and phosphorylation pathways regulates gephyrin scaffolding. Pharmacological intervention of SUMO pathway or transgenic expression of SUMOylation-deficient gephyrin variants rescued gephyrin clustering in CA1 or neocortical neurons of Gabra2-null mice, which otherwise lack gephyrin clusters, indicating that gephyrin SUMO modification is an essential determinant for scaffolding at GABAergic synapses. Together, our results demonstrate that concerted modifications on a protein scaffold by evolutionarily conserved yet functionally diverse signalling pathways facilitate GABAergic transmission. Gephyrin is a cytoplasmic scaffolding protein that selectively forms postsynaptic scaffolds at GABAergic and glycinergic synapses. Here the authors characterize regulatory mechanisms determining gephyrin scaffolding and GABAA receptor synaptic transmission that involve acetylation, SUMOylation and phosphorylation.
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Affiliation(s)
- Himanish Ghosh
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Luca Auguadri
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Sereina Battaglia
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Zahra Simone Thirouin
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Khaled Zemoura
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Simon Messner
- Department of Molecular Mechanisms of Disease, University of Zurich, CH 8057 Zurich, Switzerland
| | - Mario A Acuña
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Gonzalo E Yévenes
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Andrea Dieter
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Hiroshi Kawasaki
- Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Michael O Hottiger
- Department of Molecular Mechanisms of Disease, University of Zurich, CH 8057 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland.,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, CH 8093 Zurich, Switzerland
| | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
| | - Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland.,Center for Neuroscience Zurich, CH 8057 Zurich, Switzerland
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31
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Langlhofer G, Villmann C. The Intracellular Loop of the Glycine Receptor: It's not all about the Size. Front Mol Neurosci 2016; 9:41. [PMID: 27330534 PMCID: PMC4891346 DOI: 10.3389/fnmol.2016.00041] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/17/2016] [Indexed: 11/15/2022] Open
Abstract
The family of Cys-loop receptors (CLRs) shares a high degree of homology and sequence identity. The overall structural elements are highly conserved with a large extracellular domain (ECD) harboring an α-helix and 10 β-sheets. Following the ECD, four transmembrane domains (TMD) are connected by intracellular and extracellular loop structures. Except the TM3–4 loop, their length comprises 7–14 residues. The TM3–4 loop forms the largest part of the intracellular domain (ICD) and exhibits the most variable region between all CLRs. The ICD is defined by the TM3–4 loop together with the TM1–2 loop preceding the ion channel pore. During the last decade, crystallization approaches were successful for some members of the CLR family. To allow crystallization, the intracellular loop was in most structures replaced by a short linker present in prokaryotic CLRs. Therefore, no structural information about the large TM3–4 loop of CLRs including the glycine receptors (GlyRs) is available except for some basic stretches close to TM3 and TM4. The intracellular loop has been intensively studied with regard to functional aspects including desensitization, modulation of channel physiology by pharmacological substances, posttranslational modifications, and motifs important for trafficking. Furthermore, the ICD interacts with scaffold proteins enabling inhibitory synapse formation. This review focuses on attempts to define structural and functional elements within the ICD of GlyRs discussed with the background of protein-protein interactions and functional channel formation in the absence of the TM3–4 loop.
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Affiliation(s)
- Georg Langlhofer
- Institute of Clinical Neurobiology, University of Würzburg Würzburg, Germany
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University of Würzburg Würzburg, Germany
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32
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Schorova L, Martin S. Sumoylation in Synaptic Function and Dysfunction. Front Synaptic Neurosci 2016; 8:9. [PMID: 27199730 PMCID: PMC4848311 DOI: 10.3389/fnsyn.2016.00009] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/08/2016] [Indexed: 12/18/2022] Open
Abstract
Sumoylation has recently emerged as a key post-translational modification involved in many, if not all, biological processes. Small Ubiquitin-like Modifier (SUMO) polypeptides are covalently attached to specific lysine residues of target proteins through a dedicated enzymatic pathway. Disruption of the SUMO enzymatic pathway in the developing brain leads to lethality indicating that this process exerts a central role during embryonic and post-natal development. However, little is still known regarding how this highly dynamic protein modification is regulated in the mammalian brain despite an increasing number of data implicating sumoylated substrates in synapse formation, synaptic communication and plasticity. The aim of this review is therefore to briefly describe the enzymatic SUMO pathway and to give an overview of our current knowledge on the function and dysfunction of protein sumoylation at the mammalian synapse.
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Affiliation(s)
- Lenka Schorova
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
| | - Stéphane Martin
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
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33
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Choi JH, Park JY, Park SP, Lee H, Han S, Park KH, Suh YH. Regulation of mGluR7 trafficking by SUMOylation in neurons. Neuropharmacology 2015; 102:229-35. [PMID: 26631532 DOI: 10.1016/j.neuropharm.2015.11.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/13/2015] [Accepted: 11/22/2015] [Indexed: 11/26/2022]
Abstract
SUMOylation is a post-translational modification by which Small Ubiquitin-like MOdifier (SUMO) proteins are covalently linked to the lysine residues of target proteins via an enzymatic cascade. SUMOylation at the synapse plays an important regulatory role in a wide variety of neuronal function such as synapse formation and receptor endocytosis. The metabotropic glutamate receptor type 7 (mGluR7), a presynaptic G protein-coupled receptor, modulates excitatory neurotransmission and synaptic plasticity by inhibiting neurotransmitter release. The SUMO conjugation of mGluR7 has been demonstrated from several in vitro studies, however, it has not been successful in identifying SUMOylation of full-length mGluR7 in vivo. In the present study, we find that mGluR7 at Lys889 is a target of SUMO conjugation, which is impeded by SUMO-specific isopeptidase SENP1 in HEK 293T cells. In addition, we identify SUMOylated mGluR7 both in brain and primary cortical neurons, that is reduced by the treatment of L-AP4, mGluR7 agonist. We find that deSUMOylated mutation in mGluR7 or overexpression of SENP-1 markedly increases mGluR7 internalization in hippocampal neurons, indicating that endocytosis of mGluR7 is enhanced by the reduced SUMO conjugation of mGluR7. Furthermore, Ser862 phosphorylation facilitates SUMO conjugation of mGluR7. Together, these results reveal that SUMOylation of mGluR7 at Lys889 is required for stable surface expression of mGluR7 in neurons.
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Affiliation(s)
- Ji-Hee Choi
- Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 443-721, South Korea
| | - Ji-Young Park
- Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 443-721, South Korea
| | - Seung Pyo Park
- Department of Biomedical Sciences and Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul, 110-799, South Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 110-799, South Korea
| | - Hyojin Lee
- Department of Biomedical Sciences and Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul, 110-799, South Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 110-799, South Korea
| | - Seulki Han
- Department of Biomedical Sciences and Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul, 110-799, South Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 110-799, South Korea
| | - Kyung Hee Park
- Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 443-721, South Korea
| | - Young Ho Suh
- Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 443-721, South Korea; Department of Biomedical Sciences and Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul, 110-799, South Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 110-799, South Korea.
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34
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Goo MS, Scudder SL, Patrick GN. Ubiquitin-dependent trafficking and turnover of ionotropic glutamate receptors. Front Mol Neurosci 2015; 8:60. [PMID: 26528125 PMCID: PMC4607782 DOI: 10.3389/fnmol.2015.00060] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/22/2015] [Indexed: 12/19/2022] Open
Abstract
Changes in synaptic strength underlie the basis of learning and memory and are controlled, in part, by the insertion or removal of AMPA-type glutamate receptors at the postsynaptic membrane of excitatory synapses. Once internalized, these receptors may be recycled back to the plasma membrane by subunit-specific interactions with other proteins or by post-translational modifications such as phosphorylation. Alternatively, these receptors may be targeted for destruction by multiple degradation pathways in the cell. Ubiquitination, another post-translational modification, has recently emerged as a key signal that regulates the recycling and trafficking of glutamate receptors. In this review, we will discuss recent findings on the role of ubiquitination in the trafficking and turnover of ionotropic glutamate receptors and plasticity of excitatory synapses.
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Affiliation(s)
- Marisa S Goo
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Samantha L Scudder
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Gentry N Patrick
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
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35
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Martins WC, Tasca CI, Cimarosti H. Battling Alzheimer's Disease: Targeting SUMOylation-Mediated Pathways. Neurochem Res 2015; 41:568-78. [PMID: 26227998 DOI: 10.1007/s11064-015-1681-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 06/29/2015] [Accepted: 07/22/2015] [Indexed: 01/10/2023]
Abstract
SUMO (small ubiquitin-like modifier) conjugation is a critically important control process in all eukaryotic cells, because it acts as a biochemical switch and regulates the function of hundreds of proteins in many different pathways. Although the diverse functional consequences and molecular targets of SUMOylation remain largely unknown, SUMOylation is becoming increasingly implicated in the pathophysiology of Alzheimer's disease (AD). Apart from the central SUMO-modified disease-associated proteins, such as amyloid precursor protein, amyloid β, and tau, SUMOylation also regulates several other processes underlying AD. These are involved in inflammation, mitochondrial dynamics, synaptic transmission and plasticity, as well as in protective responses to cell stress. Herein, we review current reports on the involvement of SUMOylation in AD, and present an overview of potential SUMO targets and pathways underlying AD pathogenesis.
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Affiliation(s)
- Wagner Carbolin Martins
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Carla Inês Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Helena Cimarosti
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil.
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36
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Cabasso O, Pekar O, Horowitz M. SUMOylation of EHD3 Modulates Tubulation of the Endocytic Recycling Compartment. PLoS One 2015; 10:e0134053. [PMID: 26226295 PMCID: PMC4520680 DOI: 10.1371/journal.pone.0134053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/03/2015] [Indexed: 11/18/2022] Open
Abstract
Endocytosis defines the entry of molecules or macromolecules through the plasma membrane as well as membrane trafficking in the cell. It depends on a large number of proteins that undergo protein-protein and protein-phospholipid interactions. EH Domain containing (EHDs) proteins formulate a family, whose members participate in different stages of endocytosis. Of the four mammalian EHDs (EHD1-EHD4) EHD1 and EHD3 control traffic to the endocytic recycling compartment (ERC) and from the ERC to the plasma membrane, while EHD2 modulates internalization. Recently, we have shown that EHD2 undergoes SUMOylation, which facilitates its exit from the nucleus, where it serves as a co-repressor. In the present study, we tested whether EHD3 undergoes SUMOylation and what is its role in endocytic recycling. We show, both in-vitro and in cell culture, that EHD3 undergoes SUMOylation. Localization of EHD3 to the tubular structures of the ERC depends on its SUMOylation on lysines 315 and 511. Absence of SUMOylation of EHD3 has no effect on its dimerization, an important factor in membrane localization of EHD3, but has a dominant negative effect on its appearance in tubular ERC structures. Non-SUMOylated EHD3 delays transferrin recycling from the ERC to the cell surface. Our findings indicate that SUMOylation of EHD3 is involved in tubulation of the ERC membranes, which is important for efficient recycling.
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Affiliation(s)
- Or Cabasso
- Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv, Israel
| | - Olga Pekar
- Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv, Israel
| | - Mia Horowitz
- Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv, Israel
- * E-mail:
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37
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SUMO1 Affects Synaptic Function, Spine Density and Memory. Sci Rep 2015; 5:10730. [PMID: 26022678 PMCID: PMC4650663 DOI: 10.1038/srep10730] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/17/2015] [Indexed: 01/19/2023] Open
Abstract
Small ubiquitin-like modifier-1 (SUMO1) plays a number of roles in cellular events and recent evidence has given momentum for its contributions to neuronal development and function. Here, we have generated a SUMO1 transgenic mouse model with exclusive overexpression in neurons in an effort to identify in vivo conjugation targets and the functional consequences of their SUMOylation. A high-expressing line was examined which displayed elevated levels of mono-SUMO1 and increased high molecular weight conjugates in all brain regions. Immunoprecipitation of SUMOylated proteins from total brain extract and proteomic analysis revealed ~95 candidate proteins from a variety of functional classes, including a number of synaptic and cytoskeletal proteins. SUMO1 modification of synaptotagmin-1 was found to be elevated as compared to non-transgenic mice. This observation was associated with an age-dependent reduction in basal synaptic transmission and impaired presynaptic function as shown by altered paired pulse facilitation, as well as a decrease in spine density. The changes in neuronal function and morphology were also associated with a specific impairment in learning and memory while other behavioral features remained unchanged. These findings point to a significant contribution of SUMO1 modification on neuronal function which may have implications for mechanisms involved in mental retardation and neurodegeneration.
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38
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Abstract
Monobodies are small recombinant proteins designed to bind with high affinity to target proteins. Monobodies have been generated to mimic the SIM [SUMO (small ubiquitin-like modifier)-interacting motif] present in many SUMO target proteins, but their properties have not been determined in cells. In the present study we characterize the properties of two SUMO1-specific monobodies (hS1MB4 and hS1MB5) in HEK (human embyronic kidney)-293 and HeLa cells and examine their ability to purify SUMO substrates from cell lines and rat brain. Both hS1MB4 and hS1MB5 compared favourably with commercially available antibodies and were highly selective for binding to SUMO1 over SUMO2/3 in pull-down assays against endogenous and overexpressed SUMO and SUMOylated proteins. Monobodies expressed in HeLa cells displayed a nuclear and cytosolic distribution that overlaps with SUMO1. Expression of the monobodies effectively inhibited protein SUMOylation by SUMO1 and, surprisingly, by SUMO2/3, but were not cytotoxic for at least 36 h. We attribute the effects on SUMO2/3 to the role of SUMO1 in chain termination and/or monobody inhibition of the SUMO-conjugating E1 enzyme complex. Taken together, these data provide the first demonstration that monobodies represent useful new tools both to isolate SUMO conjugates and to probe cell SUMOylation pathways in vivo.
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39
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mGlu5 receptors regulate synaptic sumoylation via a transient PKC-dependent diffusional trapping of Ubc9 into spines. Nat Commun 2014; 5:5113. [PMID: 25311713 DOI: 10.1038/ncomms6113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/01/2014] [Indexed: 12/27/2022] Open
Abstract
Sumoylation plays important roles in the modulation of protein function, neurotransmission and plasticity, but the mechanisms regulating this post-translational system in neurons remain largely unknown. Here we demonstrate that the synaptic diffusion of Ubc9, the sole conjugating enzyme of the sumoylation pathway, is regulated by synaptic activity. We use restricted photobleaching/photoconversion of individual hippocampal spines to measure the diffusion properties of Ubc9 and show that it is regulated through an mGlu5R-dependent signalling pathway. Increasing synaptic activity with a GABAA receptor antagonist or directly activating mGlu5R increases the synaptic residency time of Ubc9 via a Gαq/PLC/Ca(2+)/PKC cascade. This activation promotes a transient synaptic trapping of Ubc9 through a PKC phosphorylation-dependent increase of Ubc9 recognition to phosphorylated substrates and consequently leads to the modulation of synaptic sumoylation. Our data demonstrate that Ubc9 diffusion is subject to activity-dependent regulatory processes and provide a mechanism for the dynamic changes in sumoylation occurring during synaptic transmission.
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40
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Henley JM, Craig TJ, Wilkinson KA. Neuronal SUMOylation: mechanisms, physiology, and roles in neuronal dysfunction. Physiol Rev 2014; 94:1249-85. [PMID: 25287864 PMCID: PMC4187031 DOI: 10.1152/physrev.00008.2014] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Protein SUMOylation is a critically important posttranslational protein modification that participates in nearly all aspects of cellular physiology. In the nearly 20 years since its discovery, SUMOylation has emerged as a major regulator of nuclear function, and more recently, it has become clear that SUMOylation has key roles in the regulation of protein trafficking and function outside of the nucleus. In neurons, SUMOylation participates in cellular processes ranging from neuronal differentiation and control of synapse formation to regulation of synaptic transmission and cell survival. It is a highly dynamic and usually transient modification that enhances or hinders interactions between proteins, and its consequences are extremely diverse. Hundreds of different proteins are SUMO substrates, and dysfunction of protein SUMOylation is implicated in a many different diseases. Here we briefly outline core aspects of the SUMO system and provide a detailed overview of the current understanding of the roles of SUMOylation in healthy and diseased neurons.
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Affiliation(s)
- Jeremy M Henley
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Tim J Craig
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Kevin A Wilkinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
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41
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Sun H, Lu L, Zuo Y, Wang Y, Jiao Y, Zeng WZ, Huang C, Zhu MX, Zamponi GW, Zhou T, Xu TL, Cheng J, Li Y. Kainate receptor activation induces glycine receptor endocytosis through PKC deSUMOylation. Nat Commun 2014; 5:4980. [PMID: 25236484 PMCID: PMC4199113 DOI: 10.1038/ncomms5980] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 08/13/2014] [Indexed: 01/21/2023] Open
Abstract
Surface expression and regulated endocytosis of glycine receptors (GlyRs) play a critical function in balancing neuronal excitability. SUMOylation (SUMO modification) is of critical importance for maintaining neuronal function in the central nervous system. Here we show that activation of kainate receptors (KARs) causes GlyR endocytosis in a calcium- and protein kinase C (PKC)-dependent manner, leading to reduced GlyR-mediated synaptic activity in cultured spinal cord neurons and the superficial dorsal horn of rat spinal cord slices. This effect requires SUMO1/sentrin-specific peptidase 1 (SENP1)-mediated deSUMOylation of PKC, indicating that the crosstalk between KARs and GlyRs relies on the SUMOylation status of PKC. SENP1-mediated deSUMOylation of PKC is involved in the kainate-induced GlyR endocytosis and thus plays an important role in the anti-homeostatic regulation between excitatory and inhibitory ligand-gated ion channels. Altogether, we have identified a SUMOylation-dependent regulatory pathway for GlyR endocytosis, which may have important physiological implications for proper neuronal excitability. Maintenance of proper membrane excitability is vital to neuronal function and in several neuronal types this relies on a balance between receptor-mediated excitation and inhibition. Here the authors report a crosstalk between excitatory kainate receptors and inhibitory glycine receptors that relies on the SUMOylation status of PKC.
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Affiliation(s)
- Hao Sun
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Li Lu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yong Zuo
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yan Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yingfu Jiao
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Zheng Zeng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chao Huang
- Center for Translational Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary T2N 4 N1, Alberta, Canada
| | - Tong Zhou
- Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Tian-Le Xu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jinke Cheng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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42
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Pahl S, Tapken D, Haering SC, Hollmann M. Trafficking of kainate receptors. MEMBRANES 2014; 4:565-95. [PMID: 25141211 PMCID: PMC4194049 DOI: 10.3390/membranes4030565] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 08/04/2014] [Accepted: 08/12/2014] [Indexed: 11/17/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) mediate the vast majority of excitatory neurotransmission in the central nervous system of vertebrates. In the protein family of iGluRs, kainate receptors (KARs) comprise the probably least well understood receptor class. Although KARs act as key players in the regulation of synaptic network activity, many properties and functions of these proteins remain elusive until now. Especially the precise pre-, extra-, and postsynaptic localization of KARs plays a critical role for neuronal function, as an unbalanced localization of KARs would ultimately lead to dysregulated neuronal excitability. Recently, important advances in the understanding of the regulation of surface expression, function, and agonist-dependent endocytosis of KARs have been achieved. Post-translational modifications like PKC-mediated phosphorylation and SUMOylation have been reported to critically influence surface expression and endocytosis, while newly discovered auxiliary proteins were shown to shape the functional properties of KARs.
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Affiliation(s)
- Steffen Pahl
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Daniel Tapken
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Simon C Haering
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Michael Hollmann
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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Mori Y, Fukuda M, Henley JM. Small GTPase Rab17 regulates the surface expression of kainate receptors but not α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in hippocampal neurons via dendritic trafficking of Syntaxin-4 protein. J Biol Chem 2014; 289:20773-87. [PMID: 24895134 PMCID: PMC4110286 DOI: 10.1074/jbc.m114.550632] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/20/2014] [Indexed: 02/04/2023] Open
Abstract
Glutamate receptors are fundamental for control synaptic transmission, synaptic plasticity, and neuronal excitability. However, many of the molecular mechanisms underlying their trafficking remain elusive. We previously demonstrated that the small GTPase Rab17 regulates dendritic trafficking in hippocampal neurons. Here, we investigated the role(s) of Rab17 in AMPA receptor (AMPAR) and kainate receptor (KAR) trafficking. Although Rab17 knockdown did not affect surface expression of the AMPAR subunit GluA1 under basal or chemically induced long term potentiation conditions, it significantly reduced surface expression of the KAR subunit GluK2. Rab17 co-localizes with Syntaxin-4 in the soma, dendritic shaft, the tips of developing hippocampal neurons, and in spines. Rab17 knockdown caused Syntaxin-4 redistribution away from dendrites and into axons in developing hippocampal neurons. Syntaxin-4 knockdown reduced GluK2 but had no effect on GluA1 surface expression. Moreover, overexpression of constitutively active Rab17 promoted dendritic surface expression of GluK2 by enhancing Syntaxin-4 translocation to dendrites. These data suggest that Rab17 mediates the dendritic trafficking of Syntaxin-4 to selectively regulate dendritic surface insertion of GluK2-containing KARs in rat hippocampal neurons.
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Affiliation(s)
- Yasunori Mori
- From the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom and
| | - Mitsunori Fukuda
- the Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Jeremy M. Henley
- From the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom and
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Chhunchha B, Fatma N, Kubo E, Singh DP. Aberrant sumoylation signaling evoked by reactive oxygen species impairs protective function of Prdx6 by destabilization and repression of its transcription. FEBS J 2014; 281:3357-81. [PMID: 24910119 DOI: 10.1111/febs.12866] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/24/2014] [Accepted: 06/05/2014] [Indexed: 12/20/2022]
Abstract
Loss of the cytoprotective protein peroxiredoxin 6 (Prdx6) in cells that are aging or under oxidative stress is known to be linked to the pathobiology of many age-related diseases. However, the mechanism by which Prdx6 activity goes awry is largely unknown. Using Prdx6-deficient (Prdx6(-/-) ) cells as a model for aging or redox active cells, human/mouse lens epithelial cells (LECs) facing oxidative stress and aging lenses, we found a significant increase in the levels of small ubiquitin-like modifier (Sumo)1 conjugates. These cells displayed increased levels of Sumo1 and reduced the expression of Prdx6. Specifically, we observed that Prdx6 is a target for aberrant sumoylation signaling, and that Sumo1 modification reduces its cellular abundance. LECs overexpressing Sumo1 showed reduced expression and activity of Prdx6 and its transactivator specificity protein 1 (Sp1), mRNA and protein with increased levels of reactive oxygen species; those cells were vulnerable to oxidative stress-induced cell death. A significant reduction in Prdx6, Sp1 protein and mRNA expression was observed in redox active Prdx6(-/-) cells and in aging lenses/LECs. The reduction was correlated with increased expression of Sumo1 and enrichment of the inactive form (dimeric) of Sumo-specific protease (Senp)1. Experiments with Sumo1-fused Prdx6 and Prdx6 promoter-linked to chloramphenicol acetyltransferase reporter gene constructs indicated that Sumo1 dysregulated Prdx6 activity by reducing its abundance and attenuating its transcription; in contrast, the delivery of Senp1 or Prdx6 reversed the process. The data show that reactive oxygen species-evoked aberrant sumoylation signaling affects Prdx6 activity by reducing Prdx6 abundance, as well as transcription. The findings of the present study may provide a foundation for a strategy to repair deleterious oxidative signaling generated by a reduced activity of Prdx6.
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Affiliation(s)
- Bhavana Chhunchha
- Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
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45
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Rojas A, Gueorguieva P, Lelutiu N, Quan Y, Shaw R, Dingledine R. The prostaglandin EP1 receptor potentiates kainate receptor activation via a protein kinase C pathway and exacerbates status epilepticus. Neurobiol Dis 2014; 70:74-89. [PMID: 24952362 DOI: 10.1016/j.nbd.2014.06.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/12/2014] [Accepted: 06/09/2014] [Indexed: 12/16/2022] Open
Abstract
Prostaglandin E2 (PGE2) regulates membrane excitability, synaptic transmission, plasticity, and neuronal survival. The consequences of PGE2 release following seizures has been the subject of much study. Here we demonstrate that the prostaglandin E2 receptor 1 (EP1, or Ptger1) modulates native kainate receptors, a family of ionotropic glutamate receptors widely expressed throughout the central nervous system. Global ablation of the EP1 gene in mice (EP1-KO) had no effect on seizure threshold after kainate injection but reduced the likelihood to enter status epilepticus. EP1-KO mice that did experience typical status epilepticus had reduced hippocampal neurodegeneration and a blunted inflammatory response. Further studies with native prostanoid and kainate receptors in cultured cortical neurons, as well as with recombinant prostanoid and kainate receptors expressed in Xenopus oocytes, demonstrated that EP1 receptor activation potentiates heteromeric but not homomeric kainate receptors via a second messenger cascade involving phospholipase C, calcium and protein kinase C. Three critical GluK5 C-terminal serines underlie the potentiation of the GluK2/GluK5 receptor by EP1 activation. Taken together, these results indicate that EP1 receptor activation during seizures, through a protein kinase C pathway, increases the probability of kainic acid induced status epilepticus, and independently promotes hippocampal neurodegeneration and a broad inflammatory response.
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Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
| | - Paoula Gueorguieva
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Nadia Lelutiu
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Yi Quan
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Renee Shaw
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Raymond Dingledine
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
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46
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Luo J, Ashikaga E, Rubin PP, Heimann MJ, Hildick KL, Bishop P, Girach F, Josa-Prado F, Tang LTH, Carmichael RE, Henley JM, Wilkinson KA. Receptor trafficking and the regulation of synaptic plasticity by SUMO. Neuromolecular Med 2013; 15:692-706. [PMID: 23934328 DOI: 10.1007/s12017-013-8253-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 07/25/2013] [Indexed: 12/18/2022]
Abstract
Timely and efficient information transfer at synapses is fundamental to brain function. Synapses are highly dynamic structures that exhibit long-lasting activity-dependent alterations to their structure and transmission efficiency, a phenomenon termed synaptic plasticity. These changes, which occur through alterations in presynaptic release or in the trafficking of postsynaptic receptor proteins, underpin the formation and stabilisation of neural circuits during brain development, and encode, process and store information essential for learning, memory and cognition. In recent years, it has emerged that the ubiquitin-like posttranslational modification SUMOylation is an important mediator of several aspects of neuronal and synaptic function. Through orchestrating synapse formation, presynaptic release and the trafficking of postsynaptic receptor proteins during forms of synaptic plasticity such as long-term potentiation, long-term depression and homeostatic scaling, SUMOylation is being increasingly appreciated to play a central role in neurotransmission. In this review, we outline key discoveries in this relatively new field, provide an update on recent progress regarding the targets and consequences of protein SUMOylation in synaptic function and plasticity, and highlight key outstanding questions regarding the roles of protein SUMOylation in the brain.
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Affiliation(s)
- Jia Luo
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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47
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Li Q, Muma NA. Estradiol potentiates 8-OH-DPAT-induced sumoylation of 5-HT₁A receptor: characterization and subcellular distribution of sumoylated 5-HT₁A receptors. Psychoneuroendocrinology 2013; 38:2542-53. [PMID: 23786880 PMCID: PMC3797200 DOI: 10.1016/j.psyneuen.2013.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/24/2013] [Accepted: 05/24/2013] [Indexed: 10/26/2022]
Abstract
Sumoylation is a recently described post-translational modification and only a few sumoylated neurotransmitter receptors are known. Through the present studies, we discovered that serotonin1A receptors (5-HT1A-Rs) can be sumoylated by SUMO1 (small-ubiquitin-related modifier 1) protein. The SUMO1-5-HT1A-R is ∼55kDa, is located in the membrane fraction, but not the cytosol, and is distributed in all of the brain regions expressing 5-HT1A-Rs examined. Acute stimulation of 5-HT1A-Rs significantly increased SUMO1-5-HT1A-R in rat hypothalamus. Pre-treatment with estradiol for 2 days, which causes a partial desensitization of 5-HT1A-R signaling, potentiated agonist-induced increases in SUMO1-5-HT1A-Rs in the hypothalamus of ovariectomized rats. Using discontinuous gradient centrifugation followed by digitonin treatment, we found that the majority of SUMO1-5-HT1A-Rs is co-localized with endoplasmic-reticulum and trans-Golgi-network markers. Although a small proportion of SUMO1-5-HT1A-Rs are located in the detergent resistant microdomain (DRM) that contain active G-protein coupled receptors, their distribution was different from that of the Gαz protein that couples to the receptors. These data suggest that the SUMO1-5-HT1A-Rs are an inactive form of 5-HT1A-Rs, a finding further supported by results showing minimal 5-HT1A-R agonist binding to SUMO1-5-HT1A-Rs. Furthermore, SUMO1-5-HT1A-Rs in the DRM were increased by treatment with a 5-HT1A-R agonist, 8-OH-DPAT ((+)8-hydroxy-2-dipropylaminotetralin). Together, these data suggest that sumoylation of 5-HT1A-Rs may be related to 5-HT1A-R trafficking and internalization, which may contribute to 5-HT1A-R desensitization. Since 5-HT1A-Rs play an important role in mood regulation, the present results significantly impact on the understanding of the pathogenesis of affective disorders and development of better therapeutic approaches for these diseases.
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Affiliation(s)
| | - Nancy A. Muma
- Corresponding author: Nancy A. Muma, Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Drive, 5064 Malott Hall, Lawrence, Kansas 66045, , Phone: 785-864-4002, Fax: 785-864-5219
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48
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Qi Q, Liu X, Brat DJ, Ye K. Merlin sumoylation is required for its tumor suppressor activity. Oncogene 2013; 33:4893-903. [PMID: 24166499 DOI: 10.1038/onc.2013.438] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/01/2013] [Accepted: 08/12/2013] [Indexed: 12/11/2022]
Abstract
Merlin, encoded by the Neurofibromatosis 2 (NF2) gene, is a multifunctional tumor suppressor that integrates and regulates extracellular cues and intracellular signaling pathways, both at the plasma membrane and in the nucleus, to control cell proliferation, migration and invasion. Molecular mechanisms regulating merlin's tumor-suppressive activity have not been clearly defined. Here we report that merlin can be sumoylated on Lysine residue (K76) in vitro and in vivo. Sumoylation mediates merlin's intramolecular and intermolecular binding activities and regulates its cytoplasm/nucleus trafficking. Interestingly, sumoylation of merlin is regulated by its phosphorylation via Akt and PAK2 kinases. Mutation of K76 into arginine (R) abolishes its sumoylation, disrupts merlin cortical cytoskeleton residency and attenuates its stability. Using a K76R mutant merlin in a subcutaneous U87MG xenograft model, we demonstrate that merlin sumoylation is required for tumor-suppressive activity. Taken together, our findings indicate that merlin is sumoylated and that this post-translational modification is essential for tumor suppression.
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Affiliation(s)
- Q Qi
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - X Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - D J Brat
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - K Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
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49
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Sun C, Qiao H, Zhou Q, Wang Y, Wu Y, Zhou Y, Li Y. Modulation of GluK2a subunit-containing kainate receptors by 14-3-3 proteins. J Biol Chem 2013; 288:24676-90. [PMID: 23861400 PMCID: PMC3750165 DOI: 10.1074/jbc.m113.462069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 07/11/2013] [Indexed: 11/06/2022] Open
Abstract
Kainate receptors (KARs) are one of the ionotropic glutamate receptors that mediate excitatory postsynaptic currents (EPSCs) with characteristically slow kinetics. Although mechanisms for the slow kinetics of KAR-EPSCs are not totally understood, recent evidence has implicated a regulatory role of KAR-associated proteins. Here, we report that decay kinetics of GluK2a-containing receptors is modulated by closely associated 14-3-3 proteins. 14-3-3 binding requires PKC-dependent phosphorylation of serine residues localized in the carboxyl tail of the GluK2a subunit. In transfected cells, 14-3-3 binding to GluK2a slows desensitization kinetics of both homomeric GluK2a and heteromeric GluK2a/GluK5 receptors. Moreover, KAR-EPSCs at mossy fiber-CA3 synapses decay significantly faster in the 14-3-3 functional knock-out mice. Collectively, these results demonstrate that 14-3-3 proteins are an important regulator of GluK2a-containing KARs and may contribute to the slow decay kinetics of native KAR-EPSCs.
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Affiliation(s)
- Changcheng Sun
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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50
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Silveirinha V, Stephens GJ, Cimarosti H. Molecular targets underlying SUMO-mediated neuroprotection in brain ischemia. J Neurochem 2013; 127:580-91. [PMID: 23786482 DOI: 10.1111/jnc.12347] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
SUMOylation (small ubiquitin-like modifier conjugation) is an important post-translational modification which is becoming increasingly implicated in the altered protein dynamics associated with brain ischemia. The function of SUMOylation in cells undergoing ischemic stress and the identity of small ubiquitin-like modifier (SUMO) targets remain in most cases unknown. However, the emerging consensus is that SUMOylation of certain proteins might be part of an endogenous neuroprotective response. This review brings together the current understanding of the underlying mechanisms and downstream effects of SUMOylation in brain ischemia, including processes such as autophagy, mitophagy and oxidative stress. We focus on recent advances and controversies regarding key central nervous system proteins, including those associated with the nucleus, cytoplasm and plasma membrane, such as glucose transporters (GLUT1, GLUT4), excitatory amino acid transporter 2 glutamate transporters, K+ channels (K2P1, Kv1.5, Kv2.1), GluK2 kainate receptors, mGluR8 glutamate receptors and CB1 cannabinoid receptors, which are reported to be SUMO-modified. A discussion of the roles of these molecular targets for SUMOylation could play following an ischemic event, particularly with respect to their potential neuroprotective impact in brain ischemia, is proposed.
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Affiliation(s)
- Vasco Silveirinha
- School of Pharmacy, Hopkins Building, University of Reading, Whiteknights, Reading, UK
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