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Zhang T, Dolga AM, Eisel ULM, Schmidt M. Novel crosstalk mechanisms between GluA3 and Epac2 in synaptic plasticity and memory in Alzheimer's disease. Neurobiol Dis 2024; 191:106389. [PMID: 38142840 DOI: 10.1016/j.nbd.2023.106389] [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: 11/23/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease which accounts for the most cases of dementia worldwide. Impaired memory, including acquisition, consolidation, and retrieval, is one of the hallmarks in AD. At the cellular level, dysregulated synaptic plasticity partly due to reduced long-term potentiation (LTP) and enhanced long-term depression (LTD) underlies the memory deficits in AD. GluA3 containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are one of key receptors involved in rapid neurotransmission and synaptic plasticity. Recent studies revealed a novel form of GluA3 involved in neuronal plasticity that is dependent on cyclic adenosine monophosphate (cAMP), rather than N-methyl-d-aspartate (NMDA). However, this cAMP-dependent GluA3 pathway is specifically and significantly impaired by amyloid beta (Aβ), a pathological marker of AD. cAMP is a key second messenger that plays an important role in modulating memory and synaptic plasticity. We previously reported that exchange protein directly activated by cAMP 2 (Epac2), acting as a main cAMP effector, plays a specific and time-limited role in memory retrieval. From electrophysiological perspective, Epac2 facilities the maintenance of LTP, a cellular event closely associated with memory retrieval. Additionally, Epac2 was found to be involved in the GluA3-mediated plasticity. In this review, we comprehensively summarize current knowledge regarding the specific roles of GluA3 and Epac2 in synaptic plasticity and memory, and their potential association with AD.
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Affiliation(s)
- Tong Zhang
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9747 AG, Netherlands
| | - Amalia M Dolga
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Groningen Research Institute for Asthma and COPD, GRIAC, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Ulrich L M Eisel
- Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9747 AG, Netherlands
| | - Martina Schmidt
- Department of Molecular Pharmacology, University of Groningen, the Netherlands; Groningen Research Institute for Asthma and COPD, GRIAC, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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Certain N, Gan Q, Bennett J, Hsieh H, Wollmuth LP. Differential regulation of tetramerization of the AMPA receptor glutamate-gated ion channel by auxiliary subunits. J Biol Chem 2023; 299:105227. [PMID: 37673338 PMCID: PMC10558804 DOI: 10.1016/j.jbc.2023.105227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/21/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) auxiliary subunits are specialized, nontransient binding partners of AMPARs that modulate AMPAR channel gating properties and pharmacology, as well as their biogenesis and trafficking. The most well-characterized families of auxiliary subunits are transmembrane AMPAR regulatory proteins (TARPs), cornichon homologs (CNIHs), and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs (composed of GluA1-4 subunits) in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of WT and mutant AMPARs, presumably by increasing the overall stability of the tetrameric complex, an effect that is mainly mediated by interactions with the transmembrane domain of the receptor. We also find CNIH-2 and CNIH-3 show receptor subunit-specific actions in this regard with CNIH-2 enhancing both GluA1 and GluA2 tetramerization, whereas CNIH-3 only weakly enhances GluA1 tetramerization. These results are consistent with the proposed role of CNIHs as endoplasmic reticulum cargo transporters for AMPARs. In contrast, TARP γ-2, TARP γ-8, and GSG1-L have no or negligible effect on AMPAR tetramerization. On the other hand, TARP γ-2 can enhance receptor tetramerization but only when directly fused with the receptor at a maximal stoichiometry. Notably, surface expression of functional AMPARs was enhanced by CNIH-2 to a greater extent than TARP γ-2, suggesting that this distinction aids in maturation and membrane expression. These experiments define a functional distinction between CNIHs and other auxiliary subunits in the regulation of AMPAR biogenesis.
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Affiliation(s)
- Noele Certain
- Graduate Program in Molecular and Cellular Pharmacology, Stony Brook University, Stony Brook, New York, USA
| | - Quan Gan
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York, USA
| | - Joseph Bennett
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, New York, USA
| | - Helen Hsieh
- Department of Surgery, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York, USA
| | - Lonnie P Wollmuth
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, New York, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York, USA; Department of Biochemistry & Cell Biology, Stony Brook University, Stony Brook, New York, USA.
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3
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Perozzo AM, Brown PMGE, Bowie D. Alternative Splicing of the Flip/Flop Cassette and TARP Auxiliary Subunits Engage in a Privileged Relationship That Fine-Tunes AMPA Receptor Gating. J Neurosci 2023; 43:2837-2849. [PMID: 36931708 PMCID: PMC10124957 DOI: 10.1523/jneurosci.2293-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/10/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
Alternative splicing of AMPA-type glutamate receptors (AMPARs) and allosteric modulation by auxiliary subunits, such as transmembrane AMPAR regulatory proteins (TARPs), are two important mechanisms that regulate the time course of glutamatergic neurotransmission. Prior work has shown that alternative splicing of the flip/flop cassette profoundly regulates TARP γ2 modulation, where flip receptor gating exhibits robust sensitivity to TARPs while flop isoforms are relatively insensitive to TARP modulation. Whether this splice variant-specific regulation extends to other auxiliary subunit families, such as cornichons (CNIHs), GSG1L, or CKAMPs, remains unknown. Here, we demonstrate that CNIH-3 modulation is unaffected by AMPAR alternative splicing due to inherent differences in how CNIH-3 and TARP γ2 modify channel gating. CNIH-3 slows receptor deactivation from the outset of current decay, consistent with structural evidence showing its point of contact at the level of the pore. In contrast, TARP γ2 acts via the KGK site of the ligand-binding domain (LBD) to slow the onset of desensitization. Although GSG1L and CKAMP44 primarily slow recovery from desensitization, their effects on channel gating are unaffected by alternative splicing, further underlining that structural events leading to the onset and recovery from desensitization are separable. Together, this work establishes that alternative splicing and TARP auxiliary subunits form a unique partnership that governs fast glutamatergic signaling at central synapses. Since proteomic studies suggest that all native AMPARs co-assemble with at least two TARPs, allosteric coupling between the flip/flop cassette and TARPs may represent a common design element in all AMPAR complexes of the mammalian brain.SIGNIFICANCE STATEMENT All fast excitatory neurotransmission in the mammalian brain is mediated by AMPA-type glutamate receptors (AMPARs). The time course of AMPAR gating can be regulated by two distinct mechanisms: alternative splicing of the flip/flop cassette and association with auxiliary subunits. Although these regulatory mechanisms have been well studied individually, it is not clear whether alternative splicing impacts auxiliary protein modulation of AMPARs. Here, we compare the four main families of AMPAR auxiliary subunits, transmembrane AMPAR regulatory proteins (TARPs; γ2), cornichons (CNIH-3), GSG1L and CKAMPs (CKAMP44), and find a privileged relationship between TARPs and the flip/flop cassette that is not shared by others. The flop cassette acts as a master switch to override TARP action, and this coupling represents a way to fine-tune AMPAR signaling.
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Affiliation(s)
- Amanda M Perozzo
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec H3A 2B4, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Patricia M G E Brown
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec H3A 2B4, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3G 1Y6, Canada
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Certain N, Gan Q, Bennett J, Hsieh H, Wollmuth LP. Differential regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) receptor tetramerization by auxiliary subunits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527516. [PMID: 36798164 PMCID: PMC9934675 DOI: 10.1101/2023.02.07.527516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
AMPA receptor (AMPAR) auxiliary subunits are specialized, non-transient binding partners of AMPARs that modulate their ion channel gating properties and pharmacology, as well as their biogenesis and trafficking. The most well characterized families of auxiliary subunits are transmembrane AMPAR regulatory proteins (TARPs) and cornichon homologs (CNIHs) and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of wild type and mutant AMPARs, possibly by increasing the overall stability of the tetrameric complex, an effect that is mainly mediated by interactions with the transmembrane domain of the receptor. We also find CNIH-2 and CNIH-3 show receptor subunit-specific actions in this regard with CNIH-2 enhancing both GluA1 and GluA2 tetramerization whereas CNIH-3 only weakly enhances GluA1 tetramerization. These results are consistent with the proposed role of CNIHs as endoplasmic reticulum cargo transporters for AMPARs. In contrast, TARP γ-2, TARP γ-8, and GSG1-L have no or negligible effect on AMPAR tetramerization. On the other hand, TARP γ-2 can enhance receptor tetramerization but only when directly fused with the receptor at a maximal stoichiometry. Notably, surface expression of functional AMPARs was enhanced by CNIH-2 to a greater extent than TARP γ-2 suggesting that this distinction aids in maturation and membrane expression. These experiments define a functional distinction between CNIHs and other auxiliary subunits in the regulation of AMPAR biogenesis.
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Naz R, Khan A, Alghamdi BS, Ashraf GM, Alghanmi M, Ahmad A, Bashir SS, Haq QMR. An Insight into Animal Glutamate Receptors Homolog of Arabidopsis thaliana and Their Potential Applications-A Review. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11192580. [PMID: 36235446 PMCID: PMC9572488 DOI: 10.3390/plants11192580] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/19/2022] [Accepted: 08/26/2022] [Indexed: 06/01/2023]
Abstract
Most excitatory impulses received by neurons are mediated by ionotropic glutamate receptors (iGluRs). These receptors are located at the apex and play an important role in memory, neuronal development, and synaptic plasticity. These receptors are ligand-dependent ion channels that allow a wide range of cations to pass through. Glutamate, a neurotransmitter, activates three central ionotropic receptors: N-methyl-D-aspartic acid (NMDA), -amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA), and kainic acid (KA). According to the available research, excessive glutamate release causes neuronal cell death and promotes neurodegenerative disorders. Arabidopsis thaliana contains 20 glutamate receptor genes (AtGluR) comparable to the human ionotropic glutamate (iGluRs) receptor. Many studies have proved that AtGL-rec genes are involved in a number of plant growth and physiological activities, such as in the germination of seeds, roots, abiotic and biotic stress, and cell signaling, which clarify the place of these genes in plant biology. In spite of these, the iGluRs, Arabidopsis glutamate receptors (AtGluR), is associated with the ligand binding activity, which confirms the evolutionary relationship between animal and plant glutamate receptors. Along with the above activities, the impact of mammalian agonists and antagonists on Arabidopsis suggests a correlation between plant and animal glutamate receptors. In addition, these glutamate receptors (plant/animal) are being utilized for the early detection of neurogenerative diseases using the fluorescence resonance energy transfer (FRET) approach. However, a number of scientific laboratories and institutes are consistently working on glutamate receptors with different aspects. Currently, we are also focusing on Arabidopsis glutamate receptors. The current review is focused on updating knowledge on AtGluR genes, their evolution, functions, and expression, and as well as in comparison with iGluRs. Furthermore, a high throughput approach based on FRET nanosensors developed for understanding neurotransmitter signaling in animals and plants via glutamate receptors has been discussed. The updated information will aid in the future comprehension of the complex molecular dynamics of glutamate receptors and the exploration of new facts in plant/animal biology.
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Affiliation(s)
- Ruphi Naz
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Andleeb Khan
- Department of Pharmacology and Toxicology, College of Pharmacy, Jazan University, Jazan 45142, Saudi Arabia
| | - Badrah S. Alghamdi
- Department of Physiology, Neuroscience Unit, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Maimonah Alghanmi
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Altaf Ahmad
- Department of Botany, Aligarh Muslim University, Aligarh 202002, India
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Benske TM, Mu TW, Wang YJ. Protein quality control of N-methyl-D-aspartate receptors. Front Cell Neurosci 2022; 16:907560. [PMID: 35936491 PMCID: PMC9352929 DOI: 10.3389/fncel.2022.907560] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/29/2022] [Indexed: 12/23/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are glutamate-gated cation channels that mediate excitatory neurotransmission and are critical for synaptic development and plasticity in the mammalian central nervous system (CNS). Functional NMDARs typically form via the heterotetrameric assembly of GluN1 and GluN2 subunits. Variants within GRIN genes are implicated in various neurodevelopmental and neuropsychiatric disorders. Due to the significance of NMDAR subunit composition for regional and developmental signaling at synapses, properly folded receptors must reach the plasma membrane for their function. This review focuses on the protein quality control of NMDARs. Specifically, we review the quality control mechanisms that ensure receptors are correctly folded and assembled within the endoplasmic reticulum (ER) and trafficked to the plasma membrane. Further, we discuss disease-associated variants that have shown disrupted NMDAR surface expression and function. Finally, we discuss potential targeted pharmacological and therapeutic approaches to ameliorate disease phenotypes by enhancing the expression and surface trafficking of subunits harboring disease-associated variants, thereby increasing their incorporation into functional receptors.
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Affiliation(s)
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Ya-Juan Wang
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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Synaptic Dysfunction by Mutations in GRIN2B: Influence of Triheteromeric NMDA Receptors on Gain-of-Function and Loss-of-Function Mutant Classification. Brain Sci 2022; 12:brainsci12060789. [PMID: 35741674 PMCID: PMC9221112 DOI: 10.3390/brainsci12060789] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/11/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023] Open
Abstract
GRIN2B mutations are rare but often associated with patients having severe neurodevelopmental disorders with varying range of symptoms such as intellectual disability, developmental delay and epilepsy. Patient symptoms likely arise from mutations disturbing the role that the encoded NMDA receptor subunit, GluN2B, plays at neuronal connections in the developing nervous system. In this study, we investigated the cell-autonomous effects of putative gain- (GoF) and loss-of-function (LoF) missense GRIN2B mutations on excitatory synapses onto CA1 pyramidal neurons in organotypic hippocampal slices. In the absence of both native GluN2A and GluN2B subunits, functional incorporation into synaptic NMDA receptors was attenuated for GoF mutants, or almost eliminated for LoF GluN2B mutants. NMDA-receptor-mediated excitatory postsynaptic currents (NMDA-EPSCs) from synaptic GoF GluN1/2B receptors had prolonged decays consistent with their functional classification. Nonetheless, in the presence of native GluN2A, molecular replacement of native GluN2B with GoF and LoF GluN2B mutants all led to similar functional incorporation into synaptic receptors, more rapidly decaying NMDA-EPSCs and greater inhibition by TCN-201, a selective antagonist for GluN2A-containing NMDA receptors. Mechanistic insight was gained from experiments in HEK293T cells, which revealed that GluN2B GoF mutants slowed deactivation in diheteromeric GluN1/2B, but not triheteromeric GluN1/2A/2B receptors. We also show that a disease-associated missense mutation, which severely affects surface expression, causes opposing effects on NMDA-EPSC decay and charge transfer when introduced into GluN2A or GluN2B. Finally, we show that having a single null Grin2b allele has only a modest effect on NMDA-EPSC decay kinetics. Our results demonstrate that functional incorporation of GoF and LoF GluN2B mutants into synaptic receptors and the effects on EPSC decay times are highly dependent on the presence of triheteromeric GluN1/2A/2B NMDA receptors, thereby influencing the functional classification of NMDA receptor variants as GoF or LoF mutations. These findings highlight the complexity of interpreting effects of disease-causing NMDA receptor missense mutations in the context of neuronal function.
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Hansen KB, Wollmuth LP, Bowie D, Furukawa H, Menniti FS, Sobolevsky AI, Swanson GT, Swanger SA, Greger IH, Nakagawa T, McBain CJ, Jayaraman V, Low CM, Dell'Acqua ML, Diamond JS, Camp CR, Perszyk RE, Yuan H, Traynelis SF. Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels. Pharmacol Rev 2021; 73:298-487. [PMID: 34753794 PMCID: PMC8626789 DOI: 10.1124/pharmrev.120.000131] [Citation(s) in RCA: 222] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients.
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Affiliation(s)
- Kasper B Hansen
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Lonnie P Wollmuth
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Derek Bowie
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Hiro Furukawa
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Frank S Menniti
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Alexander I Sobolevsky
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Geoffrey T Swanson
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Sharon A Swanger
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Ingo H Greger
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Terunaga Nakagawa
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chris J McBain
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Vasanthi Jayaraman
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chian-Ming Low
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Mark L Dell'Acqua
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Jeffrey S Diamond
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chad R Camp
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Riley E Perszyk
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Hongjie Yuan
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Stephen F Traynelis
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
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Harb A, Vogel N, Shaib A, Becherer U, Bruns D, Mohrmann R. Auxiliary Subunits Regulate the Dendritic Turnover of AMPA Receptors in Mouse Hippocampal Neurons. Front Mol Neurosci 2021; 14:728498. [PMID: 34497491 PMCID: PMC8419334 DOI: 10.3389/fnmol.2021.728498] [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: 06/21/2021] [Accepted: 08/02/2021] [Indexed: 12/30/2022] Open
Abstract
Different families of auxiliary subunits regulate the function and trafficking of native α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in the central nervous system. While a facilitatory role of auxiliary subunits in ER export and forward trafficking of newly synthesized AMPA receptors is firmly established, it is unclear whether auxiliary subunits also control endosomal receptor turnover in dendrites. Here, we manipulated the composition of AMPA receptor complexes in cultured hippocampal neurons by overexpression of two auxiliary subunits, transmembrane AMPAR regulatory protein (TARP) γ-8 or cysteine knot AMPAR-modulating protein (CKAMP) 44a, and monitored dendritic receptor cycling in live-cell imaging experiments. Receptor surface delivery was assayed using a modified AMPA receptor subunit carrying the pH-dependent fluorophore superecliptic pHluorin (SEP-GluA1), which regains its fluorescence during receptor exocytosis, when transiting from the acidic lumen of transport organelles to the neutral extracellular medium. Strikingly, we observed a dramatic reduction in the spontaneous fusion rate of AMPA receptor-containing organelles in neurons overexpressing either type of auxiliary subunit. An analysis of intracellular receptor distribution also revealed a decreased receptor pool in dendritic recycling endosomes, suggesting that incorporation of TARPγ-8 or CKAMP44a in receptor complexes generally diminishes cycling through the endosomal compartment. To directly analyze dendritic receptor turnover, we also generated a new reporter by N-terminal fusion of a self-labeling HaloTag to an AMPA receptor subunit (HaloTag-GluA1), which allows for selective, irreversible staining of surface receptors. Pulse chase-experiments with HaloTag-GluA1 indeed demonstrated that overexpression of TARPγ-8 or CKAMP44a reduces the constitutive internalization rate of surface receptors at extrasynaptic but not synaptic sites. Thus, our data point to a yet unrecognized regulatory function of TARPγ-8 and CKAMP44a, by which these structurally unrelated auxiliary subunits delay local recycling and increase surface lifetime of extrasynaptic AMPA receptors.
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Affiliation(s)
- Ali Harb
- Zentrum für Human- und Molekularbiologie, Saarland University, Homburg, Germany.,Department of Anaesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Vogel
- Institute for Physiology, Otto-von-Guericke University, Magdeburg, Germany
| | - Ali Shaib
- Institute of Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Ute Becherer
- Institute for Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Dieter Bruns
- Institute for Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Ralf Mohrmann
- Institute for Physiology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Science, Otto-von-Guericke University, Magdeburg, Germany
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10
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Matthews PM, Pinggera A, Kampjut D, Greger IH. Biology of AMPA receptor interacting proteins - From biogenesis to synaptic plasticity. Neuropharmacology 2021; 197:108709. [PMID: 34271020 DOI: 10.1016/j.neuropharm.2021.108709] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/19/2021] [Accepted: 07/08/2021] [Indexed: 12/19/2022]
Abstract
AMPA-type glutamate receptors mediate the majority of excitatory synaptic transmission in the central nervous system. Their signaling properties and abundance at synapses are both crucial determinants of synapse efficacy and plasticity, and are therefore under sophisticated control. Unique to this ionotropic glutamate receptor (iGluR) is the abundance of interacting proteins that contribute to its complex regulation. These include transient interactions with the receptor cytoplasmic tail as well as the N-terminal domain locating to the synaptic cleft, both of which are involved in AMPAR trafficking and receptor stabilization at the synapse. Moreover, an array of transmembrane proteins operate as auxiliary subunits that in addition to receptor trafficking and stabilization also substantially impact AMPAR gating and pharmacology. Here, we provide an overview of the catalogue of AMPAR interacting proteins, and how they contribute to the complex biology of this central glutamate receptor.
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Affiliation(s)
- Peter M Matthews
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Alexandra Pinggera
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Domen Kampjut
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Ingo H Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
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11
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Horak M, Barackova P, Langore E, Netolicky J, Rivas-Ramirez P, Rehakova K. The Extracellular Domains of GluN Subunits Play an Essential Role in Processing NMDA Receptors in the ER. Front Neurosci 2021; 15:603715. [PMID: 33796003 PMCID: PMC8007919 DOI: 10.3389/fnins.2021.603715] [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: 09/07/2020] [Accepted: 02/19/2021] [Indexed: 12/31/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) belong to a family of ionotropic glutamate receptors that play essential roles in excitatory neurotransmission and synaptic plasticity in the mammalian central nervous system (CNS). Functional NMDARs consist of heterotetramers comprised of GluN1, GluN2A-D, and/or GluN3A-B subunits, each of which contains four membrane domains (M1 through M4), an intracellular C-terminal domain, a large extracellular N-terminal domain composed of the amino-terminal domain and the S1 segment of the ligand-binding domain (LBD), and an extracellular loop between M3 and M4, which contains the S2 segment of the LBD. Both the number and type of NMDARs expressed at the cell surface are regulated at several levels, including their translation and posttranslational maturation in the endoplasmic reticulum (ER), intracellular trafficking via the Golgi apparatus, lateral diffusion in the plasma membrane, and internalization and degradation. This review focuses on the roles played by the extracellular regions of GluN subunits in ER processing. Specifically, we discuss the presence of ER retention signals, the integrity of the LBD, and critical N-glycosylated sites and disulfide bridges within the NMDAR subunits, each of these steps must pass quality control in the ER in order to ensure that only correctly assembled NMDARs are released from the ER for subsequent processing and trafficking to the surface. Finally, we discuss the effect of pathogenic missense mutations within the extracellular domains of GluN subunits with respect to ER processing of NMDARs.
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Affiliation(s)
- Martin Horak
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Petra Barackova
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Emily Langore
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Jakub Netolicky
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Paula Rivas-Ramirez
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Kristyna Rehakova
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
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12
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Schwenk J, Fakler B. Building of AMPA‐type glutamate receptors in the endoplasmic reticulum and its implication for excitatory neurotransmission. J Physiol 2020; 599:2639-2653. [DOI: 10.1113/jp279025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/21/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jochen Schwenk
- Institute of Physiology, Faculty of Medicine University of Freiburg Hermann‐Herder‐Str. 7 Freiburg 79104 Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine University of Freiburg Hermann‐Herder‐Str. 7 Freiburg 79104 Germany
- Signalling Research Centres BIOSS and CIBSS Schänzlestr. 18 Freiburg 79104 Germany
- Center for Basics in NeuroModulation Breisacherstr. 4 Freiburg 79106 Germany
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13
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Salazar H, Mischke S, Plested AJR. Measurements of the Timescale and Conformational Space of AMPA Receptor Desensitization. Biophys J 2020; 119:206-218. [PMID: 32559412 PMCID: PMC7335938 DOI: 10.1016/j.bpj.2020.05.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/06/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022] Open
Abstract
Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the central nervous system. Desensitization of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid subtype after glutamate binding appears critical for brain function and involves rearrangement of the ligand binding domains (LBDs). Recently, several full-length structures of ionotropic glutamate receptors in putative desensitized states were published. These structures indicate movements of the LBDs that might be trapped by cysteine cross-links and metal bridges. We found that cysteine mutants at the interface between subunits A and C and lateral zinc bridges (between subunits C and D or A and B) can trap freely desensitizing receptors in a spectrum of states with different stabilities. Consistent with a close approach of subunits during desensitization processes, the introduction of bulky amino acids at the A-C interface produced a receptor with slow recovery from desensitization. Further, in wild-type GluA2 receptors, we detected the population of a stable desensitized state with a lifetime around 1 s. Using mutations that progressively stabilize deep desensitized states (E713T and Y768R), we were able to selectively protect receptors from cross-links at both the diagonal and lateral interfaces. Ultrafast perfusion enabled us to perform chemical modification in less than 10 ms, reporting movements associated to desensitization on this timescale within LBD dimers in resting receptors. These observations suggest that small disruptions of quaternary structure are sufficient for fast desensitization and that substantial rearrangements likely correspond to stable desensitized states that are adopted relatively slowly on a timescale much longer than physiological receptor activation.
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Affiliation(s)
- Hector Salazar
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Germany
| | - Sabrina Mischke
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Germany
| | - Andrew J R Plested
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, Berlin, Germany; Leibniz-Forschungsinstitut für Molekulare Pharmakologie Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Germany.
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14
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Structural features in the glycine-binding sites of the GluN1 and GluN3A subunits regulate the surface delivery of NMDA receptors. Sci Rep 2019; 9:12303. [PMID: 31444392 PMCID: PMC6707325 DOI: 10.1038/s41598-019-48845-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/14/2019] [Indexed: 12/13/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that play an essential role in mediating excitatory neurotransmission in the mammalian central nervous system (CNS). Functional NMDARs are tetramers composed of GluN1, GluN2A-D, and/or GluN3A-B subunits, giving rise to a wide variety of NMDAR subtypes with unique functional properties. Here, we examined the surface delivery and functional properties of NMDARs containing mutations in the glycine-binding sites in GluN1 and GluN3A subunits expressed in mammalian cell lines and primary rat hippocampal neurons. We found that the structural features of the glycine-binding sites in both GluN1 and GluN3A subunits are correlated with receptor forward trafficking to the cell surface. In addition, we found that a potentially clinically relevant mutation in the glycine-binding site of the human GluN3A subunit significantly reduces surface delivery of NMDARs. Taken together, these findings provide novel insight into how NMDARs are regulated by their glycine-binding sites and may provide important information regarding the role of NMDARs in both physiological and pathophysiological processes in the mammalian CNS.
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15
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Dawe GB, Kadir MF, Venskutonytė R, Perozzo AM, Yan Y, Alexander RP, Navarrete C, Santander EA, Arsenault M, Fuentes C, Aurousseau MR, Frydenvang K, Barrera NP, Kastrup JS, Edwardson JM, Bowie D. Nanoscale Mobility of the Apo State and TARP Stoichiometry Dictate the Gating Behavior of Alternatively Spliced AMPA Receptors. Neuron 2019; 102:976-992.e5. [DOI: 10.1016/j.neuron.2019.03.046] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/08/2019] [Accepted: 03/28/2019] [Indexed: 12/19/2022]
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16
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Abuin L, Prieto-Godino LL, Pan H, Gutierrez C, Huang L, Jin R, Benton R. In vivo assembly and trafficking of olfactory Ionotropic Receptors. BMC Biol 2019; 17:34. [PMID: 30995910 PMCID: PMC6472016 DOI: 10.1186/s12915-019-0651-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 03/22/2019] [Indexed: 01/29/2023] Open
Abstract
Background Ionotropic receptors (IRs) are a large, divergent subfamily of ionotropic glutamate receptors (iGluRs) that are expressed in diverse peripheral sensory neurons and function in olfaction, taste, hygrosensation and thermosensation. Analogous to the cell biological properties of their synaptic iGluR ancestors, IRs are thought to form heteromeric complexes that localise to the ciliated dendrites of sensory neurons. IR complexes are composed of selectively expressed ‘tuning’ receptors and one of two broadly expressed co-receptors (IR8a or IR25a). While the extracellular ligand-binding domain (LBD) of tuning IRs is likely to define the stimulus specificity of the complex, the role of this domain in co-receptors is unclear. Results We identify a sequence in the co-receptor LBD, the ‘co-receptor extra loop’ (CREL), which is conserved across IR8a and IR25a orthologues but not present in either tuning IRs or iGluRs. The CREL contains a single predicted N-glycosylation site, which we show bears a sugar modification in recombinantly expressed IR8a. Using the Drosophila olfactory system as an in vivo model, we find that a transgenically encoded IR8a mutant in which the CREL cannot be N-glycosylated is impaired in localisation to cilia in some, though not all, populations of sensory neurons expressing different tuning IRs. This defect can be complemented by the presence of endogenous wild-type IR8a, indicating that IR complexes contain at least two IR8a subunits and that this post-translational modification is dispensable for protein folding or complex assembly. Analysis of the subcellular distribution of the mutant protein suggests that its absence from sensory cilia is due to a failure in exit from the endoplasmic reticulum. Protein modelling and in vivo analysis of tuning IR and co-receptor subunit interactions by a fluorescent protein fragment complementation assay reveal that the CREL N-glycosylation site is likely to be located on the external face of a heterotetrameric IR complex. Conclusions Our data reveal an important role for the IR co-receptor LBD in control of intracellular transport, provide novel insights into the stoichiometry and assembly of IR complexes and uncover an unexpected heterogeneity in the trafficking regulation of this sensory receptor family. Electronic supplementary material The online version of this article (10.1186/s12915-019-0651-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liliane Abuin
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Lucia L Prieto-Godino
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.,Present address: The Francis Crick Institute, 1 Brill Place, London, NW1 1BF, UK
| | - Haiyun Pan
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA.,Conagen, 15 DeAngelo Dr, Bedford, MA, 01730, USA
| | - Craig Gutierrez
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
| | - Richard Benton
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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17
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AMPA Receptor Auxiliary Proteins of the CKAMP Family. Int J Mol Sci 2019; 20:ijms20061460. [PMID: 30909450 PMCID: PMC6470934 DOI: 10.3390/ijms20061460] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 12/26/2022] Open
Abstract
α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are assembled of four core subunits and several additional interacting proteins. Cystine-knot AMPA receptor-modulating proteins (CKAMPs) constitute a family of four proteins that influence the trafficking, subcellular localization and function of AMPA receptors. The four CKAMP family members CKAMP39/shisa8, CKAMP44/shisa9, CKAMP52/shisa6 and CKAMP59/shisa7 differ in their expression profile and their modulatory influence on AMPA receptor function. In this review, I report about recent findings on the differential roles of CKAMP family members.
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18
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Mueller TM, Kim P, Meador-Woodruff JH. Fractionation of Subcellular Compartments from Human Brain Tissue. Methods Mol Biol 2019; 1941:201-223. [PMID: 30707436 DOI: 10.1007/978-1-4939-9077-1_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Subcellular fractionation methods permit the isolation, purification, and/or enrichment of specific cellular compartments from complex tissue samples. Enrichment of multiple subcellular compartments from the same tissue sample permits comparisons of the spatial distribution of target proteins between specific intracellular compartments and, in some cases, can provide information about spatiotemporal processing of key cellular components. Here we describe a method to generate subcellular fractions enriched for heavy membranes and nuclei, rough and smooth endoplasmic reticulum membranes, light membranes and cytosol, synapses, and other intermediate cellular membranes from postmortem human brain tissue. These subcellular fractions can be used in a variety of downstream applications to assess the localization, relative abundance, and stoichiometry of glutamate receptor subunits along the forward trafficking pathway.
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Affiliation(s)
- Toni M Mueller
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Pitna Kim
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - James H Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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19
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Buonarati OR, Hammes EA, Watson JF, Greger IH, Hell JW. Mechanisms of postsynaptic localization of AMPA-type glutamate receptors and their regulation during long-term potentiation. Sci Signal 2019; 12:12/562/eaar6889. [PMID: 30600260 PMCID: PMC7175813 DOI: 10.1126/scisignal.aar6889] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
l-Glutamate is the main excitatory neurotransmitter in the brain, with postsynaptic responses to its release predominantly mediated by AMPA-type glutamate receptors (AMPARs). A critical component of synaptic plasticity involves changes in the number of responding postsynaptic receptors, which are dynamically recruited to and anchored at postsynaptic sites. Emerging findings continue to shed new light on molecular mechanisms that mediate AMPAR postsynaptic trafficking and localization. Accordingly, unconventional secretory trafficking of AMPARs occurs in dendrites, from the endoplasmic reticulum (ER) through the ER-Golgi intermediary compartment directly to recycling endosomes, independent of the Golgi apparatus. Upon exocytosis, AMPARs diffuse in the plasma membrane to reach the postsynaptic site, where they are trapped to contribute to transmission. This trapping occurs through a combination of both intracellular interactions, such as TARP (transmembrane AMPAR regulatory protein) binding to α-actinin-stabilized PSD-95, and extracellular interactions through the receptor amino-terminal domain. These anchoring mechanisms may facilitate precise receptor positioning with respect to glutamate release sites to enable efficient synaptic transmission.
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Affiliation(s)
- Olivia R. Buonarati
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - Erik A. Hammes
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - Jake F. Watson
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Ingo H. Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Johannes W. Hell
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA,Correspondence:
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20
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Jacobi E, von Engelhardt J. AMPA receptor complex constituents: Control of receptor assembly, membrane trafficking and subcellular localization. Mol Cell Neurosci 2018; 91:67-75. [DOI: 10.1016/j.mcn.2018.05.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 05/15/2018] [Accepted: 05/24/2018] [Indexed: 11/29/2022] Open
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21
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Gratacòs-Batlle E, Olivella M, Sánchez-Fernández N, Yefimenko N, Miguez-Cabello F, Fadó R, Casals N, Gasull X, Ambrosio S, Soto D. Mechanisms of CPT1C-Dependent AMPAR Trafficking Enhancement. Front Mol Neurosci 2018; 11:275. [PMID: 30135643 PMCID: PMC6092487 DOI: 10.3389/fnmol.2018.00275] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/20/2018] [Indexed: 12/19/2022] Open
Abstract
In neurons, AMPA receptor (AMPAR) function depends essentially on their constituent components:the ion channel forming subunits and ion channel associated proteins. On the other hand, AMPAR trafficking is tightly regulated by a vast number of intracellular neuronal proteins that bind to AMPAR subunits. It has been recently shown that the interaction between the GluA1 subunit of AMPARs and carnitine palmitoyltransferase 1C (CPT1C), a novel protein partner of AMPARs, is important in modulating surface expression of these ionotropic glutamate receptors. Indeed, synaptic transmission in CPT1C knockout (KO) mice is diminished supporting a positive trafficking role for that protein. However, the molecular mechanisms of such modulation remain unknown although a putative role of CPT1C in depalmitoylating GluA1 has been hypothesized. Here, we explore that possibility and show that CPT1C effect on AMPARs is likely due to changes in the palmitoylation state of GluA1. Based on in silico analysis, Ser 252, His 470 and Asp 474 are predicted to be the catalytic triad responsible for CPT1C palmitoyl thioesterase (PTE) activity. When these residues are mutated or when PTE activity is inhibited, the CPT1C effect on AMPAR trafficking is abolished, validating the CPT1C catalytic triad as being responsible for PTE activity on AMPAR. Moreover, the histidine residue (His 470) of CPT1C is crucial for the increase in GluA1 surface expression in neurons and the H470A mutation impairs the depalmitoylating catalytic activity of CPT1C. Finally, we show that CPT1C effect seems to be specific for this CPT1 isoform and it takes place solely at endoplasmic reticulum (ER). This work adds another facet to the impressive degree of molecular mechanisms regulating AMPAR physiology.
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Affiliation(s)
- Esther Gratacòs-Batlle
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Mireia Olivella
- Grup de Recerca en Bioinformàtica i Estadística Mèdica, Universitat de Vic, Barcelona, Spain
| | - Nuria Sánchez-Fernández
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Natalia Yefimenko
- Laboratori de Neurobiologia, Department de Patologia i Terapèutica Experimental, Facultat de Medicina i Ciències de la Salut, Campus Universitari de Bellvitge, Universitat de Barcelona, Barcelona, Spain
| | - Federico Miguez-Cabello
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Rut Fadó
- Department de Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Barcelona, Spain
| | - Núria Casals
- Department de Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Barcelona, Spain
| | - Xavier Gasull
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Santiago Ambrosio
- Unitat de Bioquímica, Departament de Ciències Fisiològiques, Facultat de Medicina i Ciències de la Salut, Campus Universitari de Bellvitge, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques de Bellvitge (IDIBELL), Barcelona, Spain
| | - David Soto
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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22
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Abstract
Pharmacological chaperones (PCs) are small molecules that bind to nascent protein targets to facilitate their biogenesis. The ability of PCs to assist in the folding and subsequent forward trafficking of disease-causative protein misfolding mutants has opened new avenues for the treatment of conformational diseases such as cystic fibrosis and lysosomal storage disorders. In this chapter, an overview of the use of PCs for the treatment of conformational disorders is provided. Beyond the therapeutic application of PCs for the treatment of these disorders, pharmacological chaperoning of wild-type integral membrane proteins is discussed. Central to this discussion is the notion that the endoplasmic reticulum is a reservoir of viable but inefficiently processed wild-type protein folding intermediates whose biogenesis can be facilitated by PCs to increase functional pools. To date, the potential therapeutic use of PCs to enhance the biogenesis of wild-type proteins has received little attention. Here the rationale for the development of PCs that target WT proteins is discussed. Also considered is the likelihood that some commonly used therapeutic agents may exert unrecognized pharmacological chaperoning activity on wild-type targets in patient populations.
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Affiliation(s)
- Nancy J Leidenheimer
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA.
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Leidenheimer NJ. Cognate Ligand Chaperoning: a Novel Mechanism for the Post-translational Regulation of Neurotransmitter Receptor Biogenesis. Front Cell Neurosci 2017; 11:245. [PMID: 28860972 PMCID: PMC5559506 DOI: 10.3389/fncel.2017.00245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/02/2017] [Indexed: 11/13/2022] Open
Abstract
The functional unit for inter-neuronal communication in the central nervous system is the neuronal synapse. The number of postsynaptic neurotransmitter receptors at the cell surface is an important determinant of synaptic efficacy and plasticity. A diverse array of post-translational processes regulate postsynaptic receptor number, including receptor exocytosis, lateral diffusion, surface stabilization, endocytosis, and recycling, thus highlighting the importance of mechanisms that control postsynaptic receptor levels. Another putative post-translational mechanism for regulating receptor surface expression is cognate ligand chaperoning. It has been proposed that neurotransmitters function as cognate ligand chaperones by binding, within the endoplasmic reticulum (ER) lumen, to their nascent neurotransmitter receptors and facilitating receptor biogenesis. Here we discuss proof-of-concept evidence that small molecules can selectively facilitate the biogenesis of their targets and examine the specific evidence in support of cognate ligand chaperoning of neurotransmitter receptor biogenesis.
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Affiliation(s)
- Nancy J Leidenheimer
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences CenterShreveport, LA, United States
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24
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Tseng YH, Chuang PH, Huang YR, Chen CL. Computational Investigation into the Interactions of Traditional Chinese Medicine Molecules of WenQingYin with GluR2. Int J Mol Sci 2017; 18:ijms18071443. [PMID: 28678159 PMCID: PMC5535934 DOI: 10.3390/ijms18071443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/21/2017] [Accepted: 07/01/2017] [Indexed: 01/27/2023] Open
Abstract
Docking and molecular dynamics simulations have been carried out to investigate the interaction of a traditional Chinese medicine, WenQingYin, with the glutamate receptor 2 (GluR2) subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. Four representative drug components of WenQingYin, namely 2-(3,4-dihydroxyphenyl)-5,6,7-trihydroxy-4H-chromen-4-one (PHF), 4-hydroxy-3-methoxybenzoic acid (HMB), 4-(2,3-dihydroxy-3-methylbutoxy)-7H-furo[3,2-g]chromen-7-one (DHMBP) and methyl 7-formylcyclopenta[c]pyran-4-carboxylate (cerbinal), and their complexes with GluR2 were simulated. Our results show that PHF, HMB, and DHMBP formed a partial hydrogen bond with GluR2 in its ligand-binding domain. However, cerbinal was not stable in the ligand-binding domain of GluR2 and induced a significant change in the structure of GluR2. Three-dimensional plots represent the contact and movement situation of the traditional Chinese medicine molecules in the ligand-binding domain. The combined results of the docking and molecular dynamics simulations provide insight into the interaction between these traditional Chinese medicine molecules and proteins.
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Affiliation(s)
- Yu-Hui Tseng
- Department of Chemistry, National Sun Yat-Sen University, 80424 Kaohsiung, Taiwan.
| | - Po-Hsiang Chuang
- Department of Chemistry, National Sun Yat-Sen University, 80424 Kaohsiung, Taiwan.
| | - Yu-Ren Huang
- Department of Chemistry, National Sun Yat-Sen University, 80424 Kaohsiung, Taiwan.
- Department of Applied Science, R.O.C. Naval Academy, 81345 Kaohsiung, Taiwan.
| | - Cheng-Lung Chen
- Department of Chemistry, National Sun Yat-Sen University, 80424 Kaohsiung, Taiwan.
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25
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Brechet A, Buchert R, Schwenk J, Boudkkazi S, Zolles G, Siquier-Pernet K, Schaber I, Bildl W, Saadi A, Bole-Feysot C, Nitschke P, Reis A, Sticht H, Al-Sanna'a N, Rolfs A, Kulik A, Schulte U, Colleaux L, Abou Jamra R, Fakler B. AMPA-receptor specific biogenesis complexes control synaptic transmission and intellectual ability. Nat Commun 2017; 8:15910. [PMID: 28675162 PMCID: PMC5500892 DOI: 10.1038/ncomms15910] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/11/2017] [Indexed: 11/25/2022] Open
Abstract
AMPA-type glutamate receptors (AMPARs), key elements in excitatory neurotransmission in the brain, are macromolecular complexes whose properties and cellular functions are determined by the co-assembled constituents of their proteome. Here we identify AMPAR complexes that transiently form in the endoplasmic reticulum (ER) and lack the core-subunits typical for AMPARs in the plasma membrane. Central components of these ER AMPARs are the proteome constituents FRRS1l (C9orf4) and CPT1c that specifically and cooperatively bind to the pore-forming GluA1-4 proteins of AMPARs. Bi-allelic mutations in the human FRRS1L gene are shown to cause severe intellectual disability with cognitive impairment, speech delay and epileptic activity. Virus-directed deletion or overexpression of FRRS1l strongly impact synaptic transmission in adult rat brain by decreasing or increasing the number of AMPARs in synapses and extra-synaptic sites. Our results provide insight into the early biogenesis of AMPARs and demonstrate its pronounced impact on synaptic transmission and brain function. The biogenesis of AMPA-type glutamate receptor (AMPAR) complexes is only partially understood. Here the authors identify transient assemblies of GluA1-4 proteins and proteins FRRS1l/CPT1c that drive formation of mature AMPAR complexes in the ER. Mutations in FRRS1l are associated with intellectual disability and epilepsy in three families.
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Affiliation(s)
- Aline Brechet
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany
| | - Rebecca Buchert
- Institute of Human Genetics, University of Erlangen, Schwabachanlage 10, Erlangen 91054, Germany
| | - Jochen Schwenk
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany.,Center for Biological Signaling Studies (BIOSS), Schänzlestr. 18, Freiburg 79104, Germany
| | - Sami Boudkkazi
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany
| | - Gerd Zolles
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany
| | - Karine Siquier-Pernet
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, Paris 75015, France
| | - Irene Schaber
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany
| | - Wolfgang Bildl
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany
| | - Abdelkrim Saadi
- Department de Neurologie, Etablissement Hospitalier Specialisé de Benaknoun, Algers, Algeria
| | - Christine Bole-Feysot
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, Paris 75015, France
| | - Patrick Nitschke
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, Paris 75015, France
| | - Andre Reis
- Institute of Human Genetics, University of Erlangen, Schwabachanlage 10, Erlangen 91054, Germany
| | - Heinrich Sticht
- Institute of Biochemistry, Emil-Fischer Center, Fahrstraße 17, Erlangen 91054, Germany
| | - Nouriya Al-Sanna'a
- Dharan Health Center, 8131 Medical Access Rd 1, Gharb al Dharan, Dharan 34465, Saudi Arabia
| | - Arndt Rolfs
- Center for Biological Signaling Studies (BIOSS), Schänzlestr. 18, Freiburg 79104, Germany.,Albrecht-Kossel-Institute for Neuroregeneration, Medical University Rostock, Gehlsheimerstr. 20, Rostock 18147, Germany
| | - Akos Kulik
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany.,Center for Biological Signaling Studies (BIOSS), Schänzlestr. 18, Freiburg 79104, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany.,Center for Biological Signaling Studies (BIOSS), Schänzlestr. 18, Freiburg 79104, Germany.,Logopharm GmbH, Schlossstr. 14, March-Buchheim 79232, Germany
| | - Laurence Colleaux
- INSERM UMR 1163, Paris-Descartes-Sorbonne Paris Cité University, Institut IMAGINE, Necker-Enfants Malades Hospital, Paris 75015, France
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Erlangen, Schwabachanlage 10, Erlangen 91054, Germany.,Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Philipp-Rosenthal-Str. 55, 04103 Leipzig, Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, Freiburg 79104, Germany.,Center for Biological Signaling Studies (BIOSS), Schänzlestr. 18, Freiburg 79104, Germany
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26
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Greger IH, Watson JF, Cull-Candy SG. Structural and Functional Architecture of AMPA-Type Glutamate Receptors and Their Auxiliary Proteins. Neuron 2017; 94:713-730. [DOI: 10.1016/j.neuron.2017.04.009] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 12/20/2022]
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27
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Han Y, Lin CY, Niu L. Functional Roles of the Edited Isoform of GluA2 in GluA2-Containing AMPA Receptor Channels. Biochemistry 2017; 56:1620-1631. [DOI: 10.1021/acs.biochem.6b01041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Yan Han
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
| | - Chi-Yen Lin
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
| | - Li Niu
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
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28
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Swanger SA, Chen W, Wells G, Burger PB, Tankovic A, Bhattacharya S, Strong KL, Hu C, Kusumoto H, Zhang J, Adams DR, Millichap JJ, Petrovski S, Traynelis SF, Yuan H. Mechanistic Insight into NMDA Receptor Dysregulation by Rare Variants in the GluN2A and GluN2B Agonist Binding Domains. Am J Hum Genet 2016; 99:1261-1280. [PMID: 27839871 PMCID: PMC5142120 DOI: 10.1016/j.ajhg.2016.10.002] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/03/2016] [Indexed: 12/30/2022] Open
Abstract
Epilepsy and intellectual disability are associated with rare variants in the GluN2A and GluN2B (encoded by GRIN2A and GRIN2B) subunits of the N-methyl-D-aspartate receptor (NMDAR), a ligand-gated ion channel with essential roles in brain development and function. By assessing genetic variation across GluN2 domains, we determined that the agonist binding domain, transmembrane domain, and the linker regions between these domains were particularly intolerant to functional variation. Notably, the agonist binding domain of GluN2B exhibited significantly more variation intolerance than that of GluN2A. To understand the ramifications of missense variation in the agonist binding domain, we investigated the mechanisms by which 25 rare variants in the GluN2A and GluN2B agonist binding domains dysregulated NMDAR activity. When introduced into recombinant human NMDARs, these rare variants identified in individuals with neurologic disease had complex, and sometimes opposing, consequences on agonist binding, channel gating, receptor biogenesis, and forward trafficking. Our approach combined quantitative assessments of these effects to estimate the overall impact on synaptic and non-synaptic NMDAR function. Interestingly, similar neurologic diseases were associated with both gain- and loss-of-function variants in the same gene. Most rare variants in GluN2A were associated with epilepsy, whereas GluN2B variants were associated with intellectual disability with or without seizures. Finally, discerning the mechanisms underlying NMDAR dysregulation by these rare variants allowed investigations of pharmacologic strategies to correct NMDAR function.
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Affiliation(s)
- Sharon A Swanger
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wenjuan Chen
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gordon Wells
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Pieter B Burger
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Anel Tankovic
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Katie L Strong
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Chun Hu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hirofumi Kusumoto
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jing Zhang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David R Adams
- Undiagnosed Diseases Network, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - John J Millichap
- Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Slavé Petrovski
- Department of Medicine, The University of Melbourne, Austin Health and Royal Melbourne Hospital, Melbourne, VIC 3050, Australia
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Hongjie Yuan
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
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29
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Structural rearrangement of the intracellular domains during AMPA receptor activation. Proc Natl Acad Sci U S A 2016; 113:E3950-9. [PMID: 27313205 DOI: 10.1073/pnas.1601747113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are ligand-gated ion channels that mediate the majority of fast excitatory neurotransmission in the central nervous system. Despite recent advances in structural studies of AMPARs, information about the specific conformational changes that underlie receptor function is lacking. Here, we used single and dual insertion of GFP variants at various positions in AMPAR subunits to enable measurements of conformational changes using fluorescence resonance energy transfer (FRET) in live cells. We produced dual CFP/YFP-tagged GluA2 subunit constructs that had normal activity and displayed intrareceptor FRET. We used fluorescence lifetime imaging microscopy (FLIM) in live HEK293 cells to determine distinct steady-state FRET efficiencies in the presence of different ligands, suggesting a dynamic picture of the resting state. Patch-clamp fluorometry of the double- and single-insert constructs showed that both the intracellular C-terminal domain (CTD) and the loop region between the M1 and M2 helices move during activation and the CTD is detached from the membrane. Our time-resolved measurements revealed unexpectedly complex fluorescence changes within these intracellular domains, providing clues as to how posttranslational modifications and receptor function interact.
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30
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Coleman SK, Hou Y, Willibald M, Semenov A, Möykkynen T, Keinänen K. Aggregation Limits Surface Expression of Homomeric GluA3 Receptors. J Biol Chem 2016; 291:8784-94. [PMID: 26912664 DOI: 10.1074/jbc.m115.689125] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Indexed: 11/06/2022] Open
Abstract
AMPA receptors are glutamate-gated cation channels assembled from GluA1-4 subunits and have properties that are strongly dependent on the subunit composition. The subunits have different propensities to form homomeric or various heteromeric receptors expressed on cell surface, but the underlying mechanisms are still poorly understood. Here, we examined the biochemical basis for the poor ability of GluA3 subunits to form homomeric receptors, linked previously to two amino acid residues, Tyr-454 and Arg-461, in its ligand binding domain (LBD). Surface expression of GluA3 was improved by co-assembly with GluA2 but not with stargazin, a trafficking chaperone and modulator of AMPA receptors. The secretion efficiency of GluA2 and GluA3 LBDs paralleled the transport difference between the respective full-length receptors and was similarly dependent on Tyr-454/Arg-461 but not on LBD stability. In comparison to GluA2, GluA3 homomeric receptors showed a strong and Tyr-454/Arg-461-dependent tendency to aggregate both in the macroscopic scale measured as lower solubility in nonionic detergent and in the microscopic scale evident as the preponderance of hydrodynamically large structures in density gradient centrifugation and native gel electrophoresis. We conclude that the impaired surface expression of homomeric GluA3 receptors is caused by nonproductive assembly and aggregation to which LBD residues Tyr-454 and Arg-461 strongly contribute. This aggregation inhibits the entry of newly synthesized GluA3 receptors to the secretory pathway.
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Affiliation(s)
- Sarah K Coleman
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Ying Hou
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Marina Willibald
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Artur Semenov
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Tommi Möykkynen
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Kari Keinänen
- From the Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
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31
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Gan Q, Dai J, Zhou HX, Wollmuth LP. The Transmembrane Domain Mediates Tetramerization of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors. J Biol Chem 2016; 291:6595-606. [PMID: 26839312 DOI: 10.1074/jbc.m115.686246] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 11/06/2022] Open
Abstract
AMPA receptors (AMPARs) mediate fast excitatory neurotransmission in the central nervous system. Functional AMPARs are tetrameric complexes with a highly modular structure, consisting of four evolutionarily distinct structural domains: an amino-terminal domain (ATD), a ligand-binding domain (LBD), a channel-forming transmembrane domain (TMD), and a carboxyl-terminal domain (CTD). Here we show that the isolated TMD of the GluA1 AMPAR is fully capable of tetramerization. Additionally, removal of the extracellular domains from the receptor did not affect membrane topology or surface delivery. Furthermore, whereas the ATD and CTD contribute positively to tetramerization, the LBD presents a barrier to the process by reducing the stability of the receptor complex. These experiments pinpoint the TMD as the "tetramerization domain" for AMPARs, with other domains playing modulatory roles. They also raise intriguing questions about the evolution of iGluRs as well as the mechanisms regulating the biogenesis of AMPAR complexes.
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Affiliation(s)
- Quan Gan
- Graduate Program in Neuroscience, From the Department of Neurobiology and Behavior
| | - Jian Dai
- the Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Huan-Xiang Zhou
- the Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Lonnie P Wollmuth
- From the Department of Neurobiology and Behavior, the Department of Biochemistry and Cell Biology, and the Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York 11794-5230 and
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32
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Lichnerova K, Kaniakova M, Park SP, Skrenkova K, Wang YX, Petralia RS, Suh YH, Horak M. Two N-glycosylation Sites in the GluN1 Subunit Are Essential for Releasing N-methyl-d-aspartate (NMDA) Receptors from the Endoplasmic Reticulum. J Biol Chem 2015; 290:18379-90. [PMID: 26045554 DOI: 10.1074/jbc.m115.656546] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Indexed: 11/06/2022] Open
Abstract
NMDA receptors (NMDARs) comprise a subclass of neurotransmitter receptors whose surface expression is regulated at multiple levels, including processing in the endoplasmic reticulum (ER), intracellular trafficking via the Golgi apparatus, internalization, recycling, and degradation. With respect to early processing, NMDARs are regulated by the availability of GluN subunits within the ER, the presence of ER retention and export signals, and posttranslational modifications, including phosphorylation and palmitoylation. However, the role of N-glycosylation, one of the most common posttranslational modifications, in regulating NMDAR processing has not been studied in detail. Using biochemistry, confocal and electron microscopy, and electrophysiology in conjunction with a lentivirus-based molecular replacement strategy, we found that NMDARs are released from the ER only when two asparagine residues in the GluN1 subunit (Asn-203 and Asn-368) are N-glycosylated. Although the GluN2A and GluN2B subunits are also N-glycosylated, their N-glycosylation sites do not appear to be essential for surface delivery of NMDARs. Furthermore, we found that removing N-glycans from native NMDARs altered the receptor affinity for glutamate. Our results suggest a novel mechanism by which neurons ensure that postsynaptic membranes contain sufficient numbers of functional NMDARs.
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Affiliation(s)
- Katarina Lichnerova
- From the Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 14220 Prague 4, Czech Republic, the Department of Physiology, Faculty of Science, Charles University in Prague, Albertov 6, 12843 Prague 2, Czech Republic
| | - Martina Kaniakova
- From the Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 14220 Prague 4, Czech Republic
| | - Seung Pyo Park
- the Department of Biomedical Sciences, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 110-799, South Korea, and
| | - Kristyna Skrenkova
- From the Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 14220 Prague 4, Czech Republic
| | - Ya-Xian Wang
- the Advanced Imaging Core, NIDCD/National Institutes of Health, Bethesda, Maryland 20892
| | - Ronald S Petralia
- the Advanced Imaging Core, NIDCD/National Institutes of Health, Bethesda, Maryland 20892
| | - Young Ho Suh
- the Department of Biomedical Sciences, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 110-799, South Korea, and
| | - Martin Horak
- From the Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 14220 Prague 4, Czech Republic,
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34
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Wang P, Eshaq RS, Meshul CK, Moore C, Hood RL, Leidenheimer NJ. Neuronal gamma-aminobutyric acid (GABA) type A receptors undergo cognate ligand chaperoning in the endoplasmic reticulum by endogenous GABA. Front Cell Neurosci 2015; 9:188. [PMID: 26041994 PMCID: PMC4435044 DOI: 10.3389/fncel.2015.00188] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/28/2015] [Indexed: 01/01/2023] Open
Abstract
GABAA receptors mediate fast inhibitory neurotransmission in the brain. Dysfunction of these receptors is associated with various psychiatric/neurological disorders and drugs targeting this receptor are widely used therapeutic agents. Both the efficacy and plasticity of GABAA receptor-mediated neurotransmission depends on the number of surface GABAA receptors. An understudied aspect of receptor cell surface expression is the post-translational regulation of receptor biogenesis within the endoplasmic reticulum (ER). We have previously shown that exogenous GABA can act as a ligand chaperone of recombinant GABAA receptors in the early secretory pathway leading us to now investigate whether endogenous GABA facilitates the biogenesis of GABAA receptors in primary cerebral cortical cultures. In immunofluorescence labeling experiments, we have determined that neurons expressing surface GABAA receptors contain both GABA and its degradative enzyme GABA transaminase (GABA-T). Treatment of neurons with GABA-T inhibitors, a treatment known to increase intracellular GABA levels, decreases the interaction of the receptor with the ER quality control protein calnexin, concomittantly increasing receptor forward-trafficking and plasma membrane insertion. The effect of GABA-T inhibition on the receptor/calnexin interaction is not due to the activation of surface GABAA or GABAB receptors. Consistent with our hypothesis that GABA acts as a cognate ligand chaperone in the ER, immunogold-labeling of rodent brain slices reveals the presence of GABA within the rough ER. The density of this labeling is similar to that present in mitochondria, the organelle in which GABA is degraded. Lastly, the effect of GABA-T inhibition on the receptor/calnexin interaction was prevented by pretreatment with a GABA transporter inhibitor. Together, these data indicate that endogenous GABA acts in the rough ER as a cognate ligand chaperone to facilitate the biogenesis of neuronal GABAA receptors.
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Affiliation(s)
- Ping Wang
- Department of Biochemistry and Molecular Biology, Louisiana State University, Health Sciences Center-Shreveport Shreveport, LA, USA
| | - Randa S Eshaq
- Department of Biochemistry and Molecular Biology, Louisiana State University, Health Sciences Center-Shreveport Shreveport, LA, USA
| | - Charles K Meshul
- Veterans Hospital Portland/Research Services/Neurocytology Laboratory and Department of Behavioral Neuroscience, Oregon Health & Science University Portland, OR, USA
| | - Cynthia Moore
- Veterans Hospital Portland/Research Services/Neurocytology Laboratory and Department of Behavioral Neuroscience, Oregon Health & Science University Portland, OR, USA
| | - Rebecca L Hood
- Veterans Hospital Portland/Research Services/Neurocytology Laboratory and Department of Behavioral Neuroscience, Oregon Health & Science University Portland, OR, USA
| | - Nancy J Leidenheimer
- Department of Biochemistry and Molecular Biology, Louisiana State University, Health Sciences Center-Shreveport Shreveport, LA, USA
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35
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Weiland M, Mancuso S, Baluska F. Signalling via glutamate and GLRs in Arabidopsis thaliana. FUNCTIONAL PLANT BIOLOGY : FPB 2015; 43:1-25. [PMID: 32480438 DOI: 10.1071/fp15109] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/14/2015] [Indexed: 05/14/2023]
Abstract
The genome of Arabidopsis thaliana (L. Heynh.) contains 20 coding sequences for homologues of animal ionotropic glutamate receptors. These glutamate receptor-like receptors act as sensors and mediators of a multitude of exogenous as well as endogenous signals and are found in all analysed plant species. Their molecular structure clearly indicates a function as integral membrane proteins with a ligand-gated ion channel activity. Altered gene expressions and the occurrence of mRNA splice variants confer a high flexibility on the gene as well as on the RNA level. An individual glutamate receptor of A. thaliana is able to bind two different ligands (most probable amino acids and their derivatives), whereas a functional receptor complex is likely to consist of four single proteins. These features enable an immense number of sensitivities against various local and temporal stimuli. This review encompasses the last 15 years of research concerning glutamate signalling and glutamate receptors in plants. It is aimed at summarising their major characteristics and involvements to obtain a broader and farer reaching perspective of these fundamental components of plant signal transduction.
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Affiliation(s)
- Matthias Weiland
- Department of Plant, Soil and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy
| | - Stefano Mancuso
- Department of Plant, Soil and Environmental Science, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy
| | - Frantisek Baluska
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany (IZMB), University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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Garcia-Alvarez G, Lu B, Yap KAF, Wong LC, Thevathasan JV, Lim L, Ji F, Tan KW, Mancuso JJ, Tang W, Poon SY, Augustine GJ, Fivaz M. STIM2 regulates PKA-dependent phosphorylation and trafficking of AMPARs. Mol Biol Cell 2015; 26:1141-59. [PMID: 25609091 PMCID: PMC4357513 DOI: 10.1091/mbc.e14-07-1222] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum and regulate store-operated Ca2+ entry. STIM2 mediates cAMP/PKA-dependent phosphorylation of the AMPA receptor subunit GluA1 in excitatory neurons. In addition, STIM2 promotes cAMP-dependent surface delivery of GluA1. STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum (ER) and regulate store-operated Ca2+ entry (SOCE). The function of STIMs in the brain is only beginning to be explored, and the relevance of SOCE in nerve cells is being debated. Here we identify STIM2 as a central organizer of excitatory synapses. STIM2, but not its paralogue STIM1, influences the formation of dendritic spines and shapes basal synaptic transmission in excitatory neurons. We further demonstrate that STIM2 is essential for cAMP/PKA-dependent phosphorylation of the AMPA receptor (AMPAR) subunit GluA1. cAMP triggers rapid migration of STIM2 to ER–plasma membrane (PM) contact sites, enhances recruitment of GluA1 to these ER-PM junctions, and promotes localization of STIM2 in dendritic spines. Both biochemical and imaging data suggest that STIM2 regulates GluA1 phosphorylation by coupling PKA to the AMPAR in a SOCE-independent manner. Consistent with a central role of STIM2 in regulating AMPAR phosphorylation, STIM2 promotes cAMP-dependent surface delivery of GluA1 through combined effects on exocytosis and endocytosis. Collectively our results point to a unique mechanism of synaptic plasticity driven by dynamic assembly of a STIM2 signaling complex at ER-PM contact sites.
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Affiliation(s)
- Gisela Garcia-Alvarez
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Bo Lu
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Kenrick An Fu Yap
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Loo Chin Wong
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Jervis Vermal Thevathasan
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Lynette Lim
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Fang Ji
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Kia Wee Tan
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - James J Mancuso
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Willcyn Tang
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Shou Yu Poon
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637553 Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
| | - Marc Fivaz
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857 Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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Horak M, Petralia RS, Kaniakova M, Sans N. ER to synapse trafficking of NMDA receptors. Front Cell Neurosci 2014; 8:394. [PMID: 25505872 PMCID: PMC4245912 DOI: 10.3389/fncel.2014.00394] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/04/2014] [Indexed: 11/26/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. There are three distinct subtypes of ionotropic glutamate receptors (GluRs) that have been identified including 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptors (AMPARs), N-methyl-D-aspartate receptors (NMDARs) and kainate receptors. The most common GluRs in mature synapses are AMPARs that mediate the fast excitatory neurotransmission and NMDARs that mediate the slow excitatory neurotransmission. There have been large numbers of recent reports studying how a single neuron regulates synaptic numbers and types of AMPARs and NMDARs. Our current research is centered primarily on NMDARs and, therefore, we will focus in this review on recent knowledge of molecular mechanisms occurring (1) early in the biosynthetic pathway of NMDARs, (2) in the transport of NMDARs after their release from the endoplasmic reticulum (ER); and (3) at the plasma membrane including excitatory synapses. Because a growing body of evidence also indicates that abnormalities in NMDAR functioning are associated with a number of human psychiatric and neurological diseases, this review together with other chapters in this issue may help to enhance research and to gain further knowledge of normal synaptic physiology as well as of the etiology of many human brain diseases.
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Affiliation(s)
- Martin Horak
- Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i. Prague, Czech Republic
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA
| | - Martina Kaniakova
- Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i. Prague, Czech Republic
| | - Nathalie Sans
- Neurocentre Magendie, Institut National de la Santé et de la Recherche Médicale, U862 Bordeaux, France ; Neurocentre Magendie, University of Bordeaux, U862 Bordeaux, France
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Furutani S, Ihara M, Nishino Y, Akamatsu M, Jones AK, Sattelle DB, Matsuda K. Exon 3 splicing and mutagenesis identify residues influencing cell surface density of heterologously expressed silkworm (Bombyx mori) glutamate-gated chloride channels. Mol Pharmacol 2014; 86:686-95. [PMID: 25261427 DOI: 10.1124/mol.114.095869] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glutamate-gated chloride channels (GluCls) mediate fast inhibitory neurotransmission in invertebrate nervous systems. Insect GluCls show alternative splicing, and, to determine its impact on channel function and pharmacology, we isolated GluCl cDNAs from larvae of the silkworm (Bombyx mori). We show that six B. mori glutamate-gated chloride channel variants are generated by splicing in exons 3 and 9 and that exons 3b and 3c are common in the brain and third thoracic ganglion. When expressed in Xenopus laevis oocytes, the three functional exon 3 variants (3a, b, c) all had similar EC50 values for l-glutamate and ivermectin (IVM); however, Imax (the maximum l-glutamate- and IVM-induced response of the channels at saturating concentrations) differed strikingly between variants, with the 3c variant showing the largest l-glutamate- and IVM-induced responses. By contrast, a partial deletion detected in exon 9 had a much smaller impact on l-glutamate and IVM actions. Binding assays using [(3)H]IVM indicate that diversity in IVM responses among the GluCl variants is mainly due to the impact on channel assembly, altering receptor cell surface numbers. GluCl variants expressed in HEK293 cells show that structural differences influenced Bmax but not Kd values of [(3)H]IVM. Domain swapping and site-directed mutagenesis identified four amino acids in exon 3c as hot spots determining the highest amplitude of the l-glutamate and IVM responses. Modeling the GluCl 3a and 3c variants suggested that three of the four amino acids contribute to intersubunit contacts, whereas the other interacts with the TM2-TM3 linker, influencing the receptor response.
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Affiliation(s)
- Shogo Furutani
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - Makoto Ihara
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - Yuri Nishino
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - Miki Akamatsu
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - Andrew K Jones
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - David B Sattelle
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
| | - Kazuhiko Matsuda
- Department of Applied Biological Chemistry, Faculty of Agriculture, Kinki University, Nakamachi Nara, Japan (S.F., M.I., K.M.); Graduate School of Life Science, University of Hyogo, Koto, Kamigori-cho, Ako-gun, Hyogo, Japan (Y.N.); Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto, Japan (M.A.); Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom (A.K.J.); and Department of Medicine, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom (D.B.S.)
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Gan Q, Salussolia CL, Wollmuth LP. Assembly of AMPA receptors: mechanisms and regulation. J Physiol 2014; 593:39-48. [PMID: 25556786 DOI: 10.1113/jphysiol.2014.273755] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/01/2014] [Indexed: 12/16/2022] Open
Abstract
AMPA receptors (AMPARs) play a critical role in excitatory glutamatergic neurotransmission. The number and subunit composition of AMPARs at synapses determines the dynamics of fast glutamatergic signalling. Functional AMPARs on the cell surface are tetramers. Thus tetrameric assembly of AMPARs represents a promising target for modulating AMPAR-mediated signalling in health and disease. Multiple structural domains within the receptor influence AMPAR assembly. In a proposed model for AMPAR assembly, the amino-terminal domain underlies the formation of a dimer pool. The transmembrane domain facilitates the formation and enhances the stability of the tetramer. The ligand-binding domain influences assembly through a process referred to as 'domain swapping'. We propose that this core AMPAR assembly process could be regulated by neuronal signals and speculate on possible mechanisms for such regulation.
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Affiliation(s)
- Quan Gan
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, NY, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behaviour, Stony Brook University, Stony Brook, NY, USA
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40
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Khodosevich K, Jacobi E, Farrow P, Schulmann A, Rusu A, Zhang L, Sprengel R, Monyer H, von Engelhardt J. Coexpressed auxiliary subunits exhibit distinct modulatory profiles on AMPA receptor function. Neuron 2014; 83:601-15. [PMID: 25066086 DOI: 10.1016/j.neuron.2014.07.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 01/30/2023]
Abstract
Gating properties and surface trafficking of AMPA receptors (AMPARs) are modulated by auxiliary subunits. Here we studied the function of coexpressed auxiliary subunits belonging to two different classes. We focused on TARP γ-8 and CKAMP44 in dentate gyrus (DG) granule cells, since both subunits are highly expressed in this cell type. TARP γ-8 and CKAMP44 decrease the rate of deactivation but have an opposing influence on receptor desensitization, which accounts for their differential modulation of synaptic short-term plasticity. Furthermore, long-term plasticity (LTP) requires TARP γ-8 but not CKAMP44. The coexpression of both auxiliary subunits is necessary for the efficient targeting of AMPARs to the cell surface of DG granule cells. Finally, electrophysiological and biochemical evidence support the notion that CKAMP44 and TARP γ-8 can be contained in the same AMPAR complex.
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Affiliation(s)
- Konstantin Khodosevich
- Department of Clinical Neurobiology, University Hospital and DKFZ Heidelberg, 69120 Heidelberg, Germany
| | - Eric Jacobi
- Synaptic Signalling and Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany; Synaptic Signalling and Neurodegeneration, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Paul Farrow
- Synaptic Signalling and Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany; Synaptic Signalling and Neurodegeneration, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Anton Schulmann
- Department of Clinical Neurobiology, University Hospital and DKFZ Heidelberg, 69120 Heidelberg, Germany
| | - Alexandru Rusu
- Department of Clinical Neurobiology, University Hospital and DKFZ Heidelberg, 69120 Heidelberg, Germany
| | - Ling Zhang
- Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Rolf Sprengel
- Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology, University Hospital and DKFZ Heidelberg, 69120 Heidelberg, Germany
| | - Jakob von Engelhardt
- Synaptic Signalling and Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany; Synaptic Signalling and Neurodegeneration, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
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41
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Fisher JL, Housley PR. Agonist binding to the GluK5 subunit is sufficient for functional surface expression of heteromeric GluK2/GluK5 kainate receptors. Cell Mol Neurobiol 2013; 33:1099-108. [PMID: 23975096 PMCID: PMC3806634 DOI: 10.1007/s10571-013-9976-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 08/12/2013] [Indexed: 10/26/2022]
Abstract
Trafficking of ionotropic glutamate receptors to the plasma membrane commonly requires occupation of the agonist binding sites. This quality control check does not typically involve receptor activation, as binding by competitive antagonists or to non-functional channels may also permit surface expression. The tetrameric kainate receptors can be assembled from five different subunits (GluK1-GluK5). While the "low-affinity" GluK1-3 subunits are able to produce functional homomeric receptors, the "high-affinity" GluK4 and GluK5 subunits require co-assembly with GluK1, 2, or 3 for surface expression. These two different types of subunits have distinct functional roles in the receptor. Therefore, we examined the relative importance of occupancy of the agonist site of the GluK2 or GluK5 subunit for surface expression of heteromeric receptors. We created subunits with a mutation within the S2 ligand-binding domain which decreased agonist affinity. Mutations at this site reduced functional surface expression of homomeric GluK2 receptors, but surface expression of these receptors could be increased with either a competitive antagonist or co-assembly with wild-type GluK5. In contrast, mutations in the GluK5 subunit reduced the production of functional heteromeric receptors at the membrane, and could not be rescued with either an antagonist or wild-type GluK2. These findings indicate that ligand binding to only the GluK5 subunit is both necessary and sufficient to allow trafficking of recombinant GluK2/K5 heteromers to the cell membrane, but that occupancy of the GluK2 site alone is not. Our results suggest a distinct role for the GluK5 subunit in regulating surface expression of heteromeric kainate receptors.
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Affiliation(s)
- Janet L Fisher
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, USA,
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Herguedas B, Krieger J, Greger IH. Receptor Heteromeric Assembly—How It Works and Why It Matters. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:361-86. [DOI: 10.1016/b978-0-12-386931-9.00013-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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43
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Balik A, Penn AC, Nemoda Z, Greger IH. Activity-regulated RNA editing in select neuronal subfields in hippocampus. Nucleic Acids Res 2012; 41:1124-34. [PMID: 23172290 PMCID: PMC3553983 DOI: 10.1093/nar/gks1045] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
RNA editing by adensosine deaminases is a widespread mechanism to alter genetic information in metazoa. In addition to modifications in non-coding regions, editing contributes to diversification of protein function, in analogy to alternative splicing. However, although splicing programs respond to external signals, facilitating fine tuning and homeostasis of cellular functions, a similar regulation has not been described for RNA editing. Here, we show that the AMPA receptor R/G editing site is dynamically regulated in the hippocampus in response to activity. These changes are bi-directional, reversible and correlate with levels of the editase Adar2. This regulation is observed in the CA1 hippocampal subfield but not in CA3 and is thus subfield/celltype-specific. Moreover, alternative splicing of the flip/flop cassette downstream of the R/G site is closely linked to the editing state, which is regulated by Ca2+. Our data show that A-to-I RNA editing has the capacity to tune protein function in response to external stimuli.
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Affiliation(s)
- Ales Balik
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
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44
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Penn A, Balik A, Wozny C, Cais O, Greger I. Activity-mediated AMPA receptor remodeling, driven by alternative splicing in the ligand-binding domain. Neuron 2012; 76:503-10. [PMID: 23141062 PMCID: PMC3500689 DOI: 10.1016/j.neuron.2012.08.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2012] [Indexed: 02/01/2023]
Abstract
The AMPA-type glutamate receptor (AMPAR) subunit composition shapes synaptic transmission and varies throughout development and in response to different input patterns. Here, we show that chronic activity deprivation gives rise to synaptic AMPAR responses with enhanced fidelity. Extrasynaptic AMPARs exhibited changes in kinetics and pharmacology associated with splicing of the alternative flip/flop exons. AMPAR mRNA indeed exhibited reprogramming of the flip/flop exons for GluA1 and GluA2 subunits in response to activity, selectively in the CA1 subfield. However, the functional changes did not directly correlate with the mRNA expression profiles but result from altered assembly of GluA1/GluA2 subunit splice variants, uncovering an additional regulatory role for flip/flop splicing in excitatory signaling. Our results suggest that activity-dependent AMPAR remodeling underlies changes in short-term synaptic plasticity and provides a mechanism for neuronal homeostasis.
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Affiliation(s)
- Andrew C. Penn
- Neurobiology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Ales Balik
- Neurobiology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Christian Wozny
- Neurobiology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Ondrej Cais
- Neurobiology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Ingo H. Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
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45
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Abstract
Ionotropic glutamate receptors, which underlie a majority of excitatory synaptic transmission in the CNS, associate with transmembrane proteins that modify their intracellular trafficking and channel gating. Significant advances have been made in our understanding of AMPA-type glutamate receptor (AMPAR) regulation by transmembrane AMPAR regulatory proteins. Less is known about the functional influence of cornichons-unrelated AMPAR-interacting proteins, identified by proteomic analysis. Here we confirm that cornichon homologs 2 and 3 (CNIH-2 and CNIH-3), but not CNIH-1, slow the deactivation and desensitization of both GluA2-containing calcium-impermeable and GluA2-lacking calcium-permeable (CP) AMPARs expressed in tsA201 cells. CNIH-2 and -3 also enhanced the glutamate sensitivity, single-channel conductance, and calcium permeability of CP-AMPARs while decreasing their block by intracellular polyamines. We examined the potential effects of CNIHs on native AMPARs by recording from rat optic nerve oligodendrocyte precursor cells (OPCs), known to express a significant population of CP-AMPARs. These glial cells exhibited surface labeling with an anti-CNIH-2/3 antibody. Two features of their AMPAR-mediated currents-the relative efficacy of the partial agonist kainate (I(KA)/I(Glu) ratio 0.4) and a greater than fivefold potentiation of kainate responses by cyclothiazide-suggest AMPAR association with CNIHs. Additionally, overexpression of CNIH-3 in OPCs markedly slowed AMPAR desensitization. Together, our experiments support the view that CNIHs are capable of altering key properties of AMPARs and suggest that they may do so in glia.
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Kaniakova M, Lichnerova K, Vyklicky L, Horak M. Single amino acid residue in the M4 domain of GluN1 subunit regulates the surface delivery of NMDA receptors. J Neurochem 2012; 123:385-95. [DOI: 10.1111/jnc.12002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 06/29/2012] [Accepted: 08/29/2012] [Indexed: 12/14/2022]
Affiliation(s)
- Martina Kaniakova
- Institute of Physiology; Academy of Sciences of the Czech Republic v.v.i.; Prague Czech Republic
| | - Katarina Lichnerova
- Institute of Physiology; Academy of Sciences of the Czech Republic v.v.i.; Prague Czech Republic
| | - Ladislav Vyklicky
- Institute of Physiology; Academy of Sciences of the Czech Republic v.v.i.; Prague Czech Republic
| | - Martin Horak
- Institute of Physiology; Academy of Sciences of the Czech Republic v.v.i.; Prague Czech Republic
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Cavanaugh A, Huang Y, Breitwieser GE. Behind the curtain: cellular mechanisms for allosteric modulation of calcium-sensing receptors. Br J Pharmacol 2012; 165:1670-1677. [PMID: 21470201 DOI: 10.1111/j.1476-5381.2011.01403.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Calcium-sensing receptors (CaSR) are integral to regulation of systemic Ca(2+) homeostasis. Altered expression levels or mutations in CaSR cause Ca(2+) handling diseases. CaSR is regulated by both endogenous allosteric modulators and allosteric drugs, including the first Food and Drug Administration-approved allosteric agonist, Cinacalcet HCl (Sensipar®). Recent studies suggest that allosteric modulators not only alter function of plasma membrane-localized CaSR, but regulate CaSR stability at the endoplasmic reticulum. This brief review summarizes our current understanding of the role of membrane-permeant allosteric agonists in cotranslational stabilization of CaSR, and highlights additional, indirect, signalling-dependent role(s) for membrane-impermeant allosteric drugs. Overall, these studies suggest that allosteric drugs act at multiple cellular organelles to control receptor abundance and hence function, and that drug hydrophobicity can bias the relative contributions of plasma membrane and intracellular organelles to CaSR abundance and signalling.
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Affiliation(s)
- Alice Cavanaugh
- Weis Center for Research, Geisinger Clinic, Danville, PA, USACancer Drug Research Laboratory, McGill University/Royal Victoria Hospital, Montreal, QC, Canada
| | - Ying Huang
- Weis Center for Research, Geisinger Clinic, Danville, PA, USACancer Drug Research Laboratory, McGill University/Royal Victoria Hospital, Montreal, QC, Canada
| | - Gerda E Breitwieser
- Weis Center for Research, Geisinger Clinic, Danville, PA, USACancer Drug Research Laboratory, McGill University/Royal Victoria Hospital, Montreal, QC, Canada
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48
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Breitwieser GE. Minireview: the intimate link between calcium sensing receptor trafficking and signaling: implications for disorders of calcium homeostasis. Mol Endocrinol 2012; 26:1482-95. [PMID: 22745192 DOI: 10.1210/me.2011-1370] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The calcium-sensing receptor (CaSR) regulates organismal Ca(2+) homeostasis. Dysregulation of CaSR expression or mutations in the CASR gene cause disorders of Ca(2+) homeostasis and contribute to the progression or severity of cancers and cardiovascular disease. This brief review highlights recent findings that define the CaSR life cycle, which controls the cellular abundance of CaSR and CaSR signaling. A novel mechanism, termed agonist-driven insertional signaling (ADIS), contributes to the unique hallmarks of CaSR signaling, including the high degree of cooperativity and the lack of functional desensitization. Agonist-mediated activation of plasma membrane-localized CaSR increases the rate of insertion of CaSR at the plasma membrane without altering the constitutive endocytosis rate, thereby acutely increasing the maximum signaling response. Prolonged CaSR signaling requires a large intracellular ADIS-mobilizable pool of CaSR, which is maintained by signaling-mediated increases in biosynthesis. This model provides a rational framework for characterizing the defects caused by CaSR mutations and the altered functional expression of wild-type CaSR in disease states. Mechanistic dissection of ADIS of CaSR should lead to optimized pharmacological approaches to normalize CaSR signaling in disorders of Ca(2+) homeostasis.
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Affiliation(s)
- Gerda E Breitwieser
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania 17822-2604, USA.
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She K, Ferreira JS, Carvalho AL, Craig AM. Glutamate binding to the GluN2B subunit controls surface trafficking of N-methyl-D-aspartate (NMDA) receptors. J Biol Chem 2012; 287:27432-45. [PMID: 22740692 DOI: 10.1074/jbc.m112.345108] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Trafficking of NMDA receptors to the surface of neurons and to synapses is critical for proper brain function and activity-dependent plasticity. Recent evidence suggests that surface trafficking of other ionotropic glutamate receptors requires ligand binding for exit from the endoplasmic reticulum. Here, we show that glutamate binding to GluN2 is required for trafficking of NMDA receptors to the cell surface. We expressed a panel of GluN2B ligand binding mutants in heterologous cells with GluN1 or in rat cultured neurons and found that surface expression correlates with glutamate efficacy. Such a correlation was found even in the presence of dominant negative dynamin to inhibit endocytosis and surface expression correlated with Golgi localization, indicating differences in forward trafficking. Co-expression of wild type GluN2B did not enhance surface expression of the mutants, suggesting that glutamate must bind to both GluN2 subunits in a tetramer and that surface expression is limited by the least avid of the two glutamate binding sites. Surface trafficking of a constitutively closed cleft GluN2B was indistinguishable from that of wild type, suggesting that glutamate concentrations are typically not limiting for forward trafficking. YFP-GluN2B expressed in hippocampal neurons from GluN2B(-/-) mice rescued synaptic accumulation at similar levels to wild type. Under these conditions, surface synaptic accumulation of YFP-GluN2B mutants also correlated with apparent glutamate affinity. Altogether, these results indicate that glutamate controls forward trafficking of NMDA receptors to the cell surface and to synapses and raise the intriguing idea that NMDA receptors may be functional at intracellular sites.
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Affiliation(s)
- Kevin She
- Brain Research Centre and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
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Kaniakova M, Krausova B, Vyklicky V, Korinek M, Lichnerova K, Vyklicky L, Horak M. Key amino acid residues within the third membrane domains of NR1 and NR2 subunits contribute to the regulation of the surface delivery of N-methyl-D-aspartate receptors. J Biol Chem 2012; 287:26423-34. [PMID: 22711533 DOI: 10.1074/jbc.m112.339085] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
N-methyl-d-aspartate (NMDA) receptors are glutamate ionotropic receptors that play critical roles in synaptic transmission, plasticity, and excitotoxicity. The functional NMDA receptors, heterotetramers composed mainly of two NR1 and two NR2 subunits, likely pass endoplasmic reticulum quality control before they are released from the endoplasmic reticulum and trafficked to the cell surface. However, the mechanism underlying this process is not clear. Using truncated and mutated NMDA receptor subunits expressed in heterologous cells, we found that the M3 domains of both NR1 and NR2 subunits contain key amino acid residues that contribute to the regulation of the number of surface functional NMDA receptors. These key residues are critical neither for the interaction between the NR1 and NR2 subunits nor for the formation of the functional receptors, but rather they regulate the early trafficking of the receptors. We also found that the identified key amino acid residues within both NR1 and NR2 M3 domains contribute to the regulation of the surface expression of unassembled NR1 and NR2 subunits. Thus, our data identify the unique role of the membrane domains in the regulation of the number of surface NMDA receptors.
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Affiliation(s)
- Martina Kaniakova
- Institute of Physiology, Academy of Sciences of the Czech Republic v.v.i., Videnska 1083, 14220 Prague 4, Czech Republic
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