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Wei M, Yang L, Su F, Liu Y, Zhao X, Luo L, Sun X, Liu S, Dong Z, Zhang Y, Shi YS, Liang J, Zhang C. ABHD6 drives endocytosis of AMPA receptors to regulate synaptic plasticity and learning flexibility. Prog Neurobiol 2024; 233:102559. [PMID: 38159878 DOI: 10.1016/j.pneurobio.2023.102559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/26/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
Trafficking of α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors (AMPARs), mediated by AMPAR interacting proteins, enabled neurons to maintain tuning capabilities at rest or active state. α/β-Hydrolase domain-containing 6 (ABHD6), an endocannabinoid hydrolase, was an AMPAR auxiliary subunit found to negatively regulate the surface delivery of AMPARs. While ABHD6 was found to prevent AMPAR tetramerization in endoplasmic reticulum, ABHD6 was also reported to localize at postsynaptic site. Yet, the role of ABHD6 interacting with AMPAR at postsynaptic site, and the physiological significance of ABHD6 regulating AMPAR trafficking remains elusive. Here, we generated the ABHD6 knockout (ABHD6KO) mice and found that deletion of ABHD6 selectively enhanced AMPAR-mediated basal synaptic responses and the surface expression of postsynaptic AMPARs. Furthermore, we found that loss of ABHD6 impaired hippocampal long-term depression (LTD) and synaptic downscaling in hippocampal synapses. AMPAR internalization assays revealed that ABHD6 was essential for neuronal activity-dependent endocytosis of surface AMPARs, which is independent of ABHD6's hydrolase activity. The defects of AMPAR endocytosis and LTD are expressed as deficits in learning flexibility in ABHD6KO mice. Collectively, we demonstrated that ABHD6 is an endocytic accessory protein promoting AMPAR endocytosis, thereby contributes to the formation of LTD, synaptic downscaling and reversal learning.
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Affiliation(s)
- Mengping Wei
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
| | - Lei Yang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Feng Su
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Ying Liu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China
| | - Xinyi Zhao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Lin Luo
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Xinyue Sun
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Sen Liu
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Zhaoqi Dong
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China
| | - Yong Zhang
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Key Lab for Neuroscience, Ministry of Education of China and National Health Commission of the PR China, IDG/McGovern Institute for Brain Research at PKU, Peking University, Beijing 100083, China
| | - Yun Stone Shi
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Medical School, Nanjing University, Nanjing 210032, China
| | - Jing Liang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China.
| | - Chen Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
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Buszka A, Pytyś A, Colvin D, Włodarczyk J, Wójtowicz T. S-Palmitoylation of Synaptic Proteins in Neuronal Plasticity in Normal and Pathological Brains. Cells 2023; 12:cells12030387. [PMID: 36766729 PMCID: PMC9913408 DOI: 10.3390/cells12030387] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Protein lipidation is a common post-translational modification of proteins that plays an important role in human physiology and pathology. One form of protein lipidation, S-palmitoylation, involves the addition of a 16-carbon fatty acid (palmitate) onto proteins. This reversible modification may affect the regulation of protein trafficking and stability in membranes. From multiple recent experimental studies, a picture emerges whereby protein S-palmitoylation is a ubiquitous yet discrete molecular switch enabling the expansion of protein functions and subcellular localization in minutes to hours. Neural tissue is particularly rich in proteins that are regulated by S-palmitoylation. A surge of novel methods of detection of protein lipidation at high resolution allowed us to get better insights into the roles of protein palmitoylation in brain physiology and pathophysiology. In this review, we specifically discuss experimental work devoted to understanding the impact of protein palmitoylation on functional changes in the excitatory and inhibitory synapses associated with neuronal activity and neuronal plasticity. The accumulated evidence also implies a crucial role of S-palmitoylation in learning and memory, and brain disorders associated with impaired cognitive functions.
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Inouye MO, Colameo D, Ammann I, Winterer J, Schratt G. miR-329- and miR-495-mediated Prr7 down-regulation is required for homeostatic synaptic depression in rat hippocampal neurons. Life Sci Alliance 2022; 5:5/12/e202201520. [PMID: 36150742 PMCID: PMC9510147 DOI: 10.26508/lsa.202201520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 12/03/2022] Open
Abstract
In rat hippocampal neurons, miRNA-dependent regulation of the synaptic Prr7 protein is required for the homeostatic synaptic depression of excitatory synapses upstream of the CDK5-SPAR pathway. Homeostatic synaptic depression (HSD) in excitatory neurons is a cell-autonomous mechanism which protects excitatory neurons from over-excitation as a consequence of chronic increases in network activity. In this process, excitatory synapses are weakened and eventually eliminated, as evidenced by a reduction in synaptic AMPA receptor expression and dendritic spine loss. Originally considered a global, cell-wide mechanism, local forms of regulation, such as the local control of mRNA translation in dendrites, are being increasingly recognized in HSD. Yet, identification of excitatory proteins whose local regulation is required for HSD is still limited. Here, we show that proline-rich protein 7/transmembrane adapter protein 3 (Prr7) down-regulation in dendrites of rat hippocampal neurons is necessary for HSD induced by chronic increase in network activity resulting from a blockade of inhibitory synaptic transmission by picrotoxin (PTX). We further identify two activity-regulated miRNAs, miR-329-3p and miR-495-3p, which inhibit Prr7 mRNA translation and are required for HSD. Moreover, we found that Prr7 knockdown reduces expression of the synaptic scaffolding protein SPAR, which is rescued by pharmacological inhibition of CDK5, indicating a role of Prr7 protein in the maintenance of excitatory synapses via protection of SPAR from degradation. Together, our findings highlight a novel HSD mechanism in which chronic activity leads to miR-329– and miR-495–mediated Prr7 reduction upstream of the CDK5-SPAR pathway.
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Affiliation(s)
- Michiko O Inouye
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - David Colameo
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Irina Ammann
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Jochen Winterer
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Gerhard Schratt
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
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Yasuda R, Hayashi Y, Hell JW. CaMKII: a central molecular organizer of synaptic plasticity, learning and memory. Nat Rev Neurosci 2022; 23:666-682. [PMID: 36056211 DOI: 10.1038/s41583-022-00624-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 12/30/2022]
Abstract
Calcium-calmodulin (CaM)-dependent protein kinase II (CaMKII) is the most abundant protein in excitatory synapses and is central to synaptic plasticity, learning and memory. It is activated by intracellular increases in calcium ion levels and triggers molecular processes necessary for synaptic plasticity. CaMKII phosphorylates numerous synaptic proteins, thereby regulating their structure and functions. This leads to molecular events crucial for synaptic plasticity, such as receptor trafficking, localization and activity; actin cytoskeletal dynamics; translation; and even transcription through synapse-nucleus shuttling. Several new tools affording increasingly greater spatiotemporal resolution have revealed the link between CaMKII activity and downstream signalling processes in dendritic spines during synaptic and behavioural plasticity. These technologies have provided insights into the function of CaMKII in learning and memory.
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Affiliation(s)
- Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA.
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA, USA.
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Zhang Y, Hu Y, Han Z, Geng Y, Xia Z, Zhou Y, Wang Z, Wang Y, Kong E, Wang X, Jia J, Zhang H. Cattle Encephalon Glycoside and Ignotin Ameliorate Palmitoylation of PSD-95 and Enhance Expression of Synaptic Proteins in the Frontal Cortex of a APPswe/PS1dE9 Mouse Model of Alzheimer’s Disease. J Alzheimers Dis 2022; 88:141-154. [PMID: 35570485 DOI: 10.3233/jad-220009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: Synaptic abnormalities in synaptic proteins are the initial hallmarks of Alzheimer’s disease (AD). The higher level of palmitoylation of synaptic proteins was closely associated with amyloid-β (Aβ) in AD. Cattle encephalon glycoside and ignotin (CEGI) have been shown to act as multitarget neurotrophic agents in APPswe/PS1dE9 (APP/PS1) transgenic AD mice. However, it is not clear whether CEGI can influence Aβ deposition or whether it does so by the regulation of protein palmitoylation and expression of synaptic proteins in transgenic AD mice. Objective: In this study, we investigated the roles of CEGI in modulating postsynaptic density protein 95 (PSD-95) palmitoylation, Aβ pathologies, and expression of synaptic-associated proteins in APP/PS1 mice. Methods: Five-month-old APP/PS1 mice were treated intraperitoneally with 6.6 mL/kg of CEGI for 6 weeks. At the end of the treatment period, APP/PS1 mice were subjected to Morris water maze to test their cognitive functions. Acyl-biotinyl exchange (ABE) for PSD-95 palmitoylation, immunofluorescent staining for expression of PSD-95, N-methyl-D-aspartic acid receptor subunit 2B (NR2B), and synaptotagmin 1 (SYT1) were assessed in mouse brain sections. Results: CEGI treatment in APP/PS1 mice significantly reduced Aβ deposition, relieved memory deficits, and decreased PSD-95 palmitoylation while markedly increasing the expression of PSD-95, NR2B, and SYT1 in the frontal cortex. There was a significant correlation between Aβ expression and PSD-95 palmitoylation in APP/PS1 mice. Conclusion: Our findings demonstrate that CEGI improved AD-like neuropathology, possibly by inhibiting PSD-95 palmitoylation, improving learning memory, and enhancing expression of synaptic-associated proteins, representing a potential therapy for AD treatment.
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Affiliation(s)
- Yinghan Zhang
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
- Department of Neurology, Xuchang Hospital, Xuchang, Henan, China
| | - Yazhuo Hu
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Zhitao Han
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Yan Geng
- Department of Neurology, The 3rd Medical Center, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Zheng Xia
- Department of Neurology, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Yongsheng Zhou
- Department of Neurology, Xuchang Hospital, Xuchang, Henan, China
| | - Zhenfu Wang
- Department of Zhantansi, Medical District of Central Beijing, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Yuanyuan Wang
- Department of Zhantansi, Medical District of Central Beijing, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Eryan Kong
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang Henan, China
| | - Xiaoning Wang
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Jianjun Jia
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Honghong Zhang
- Institute of Geriatrics, The 2nd Medical Center, Beijing Key Laboratory of Aging and Geriatrics, China National Clinical Research Center for Geriatric Disease, Chinese People’s Liberation Army General Hospital, Beijing, China
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6
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Moulin TC, Rayêe D, Schiöth HB. Dendritic spine density changes and homeostatic synaptic scaling: a meta-analysis of animal studies. Neural Regen Res 2022; 17:20-24. [PMID: 34100421 PMCID: PMC8451564 DOI: 10.4103/1673-5374.314283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mechanisms of homeostatic plasticity promote compensatory changes of cellular excitability in response to chronic changes in the network activity. This type of plasticity is essential for the maintenance of brain circuits and is involved in the regulation of neural regeneration and the progress of neurodegenerative disorders. One of the most studied homeostatic processes is synaptic scaling, where global synaptic adjustments take place to restore the neuronal firing rate to a physiological range by the modulation of synaptic receptors, neurotransmitters, and morphology. However, despite the comprehensive literature on the electrophysiological properties of homeostatic scaling, less is known about the structural adjustments that occur in the synapses and dendritic tree. In this study, we performed a meta-analysis of articles investigating the effects of chronic network excitation (synaptic downscaling) or inhibition (synaptic upscaling) on the dendritic spine density of neurons. Our results indicate that spine density is consistently reduced after protocols that induce synaptic scaling, independent of the intervention type. Then, we discuss the implication of our findings to the current knowledge on the morphological changes induced by homeostatic plasticity.
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Affiliation(s)
- Thiago C Moulin
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden; Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Danielle Rayêe
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY, USA
| | - Helgi B Schiöth
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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Zhang Y, Hell JW, Ames JB. Chemical shift assignments of the N-terminal domain of PSD95 (PSD95-NT). BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:347-350. [PMID: 33929702 PMCID: PMC8481135 DOI: 10.1007/s12104-021-10028-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/24/2021] [Indexed: 06/12/2023]
Abstract
Postsynaptic density protein-95 (PSD95) contributes to the postsynaptic architecture of neuronal synapses and plays an important role in controlling synaptic plasticity. The N-terminal domain of PSD95 (residues 1-71, called PSD95-NT) interacts with target proteins (calmodulin, α-actinin-1 and CDKL5), which regulate the Ca2+-dependent degradation of glutamate receptors. We report complete backbone NMR chemical shift assignments of PSD95-NT (BMRB No. 50752).
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Affiliation(s)
- Yonghong Zhang
- Department of Chemistry, University of California, Davis, CA, 95616, USA
- Department of Chemistry, The University of Texas Rio Grande Valley, Edinburg, TX, 78539, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, 95616, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, 95616, USA.
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Pubertal LPS treatment selectively alters PSD-95 expression in male CD-1 mice. Brain Res Bull 2021; 175:186-195. [PMID: 34333052 DOI: 10.1016/j.brainresbull.2021.07.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/11/2021] [Accepted: 07/26/2021] [Indexed: 12/22/2022]
Abstract
Puberty includes a highly stress-sensitive period with significant sex differences in the neurophysiological and behavioural outcomes of a peripheral immune challenge. Sex differences in the pubertal neuroimmune network's responses to systemic LPS may explain some of these enduring sex-specific outcomes of a pubertal immune challenge. However, the functional implications of these sex-specific neuroimmune responses on the local microenvironment are unclear. Western blots were used to examine treatment- and sex-related changes in expression of regulatory proteins in inflammation (NFκB), cell death (AIF), oxidative stress (SOD-1), and synaptic plasticity (PSD-95) following symptomatic recovery (i.e., one week post-treatment) from pubertal immune challenge. Across the four examined brain regions (i.e., hippocampus, PFC, hypothalamus, and cerebellum), only PSD-95 levels were altered one week post-treatment by the pubertal LPS treatment. Unlike their female counterparts, seven-week-old males showed increased PSD-95 expression in the hippocampus (p < .05). AIF, SOD-1, and NFκB levels in both sexes were unaffected by treatment (all p > .05), which suggests appropriate resolution of NFκB-mediated immune responses to pubertal LPS without stimulating AIF-mediated apoptosis and oxidative stress. We also report a significant male-biased sex difference in PSD-95 levels in the PFC and in cerebellar expression of SOD-1 during puberty (all p < .05). These findings highlight the sex-specific vulnerability of the pubertal hippocampus to systemic LPS and suggest that a pubertal immune challenge may expedite neurodevelopment in the hippocampus in a sex-specific manner.
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Abstract
A new study explores the neural-circuit and synaptic processes that support the transition from general to specific aversive memory formation. A critical role for homeostatic synaptic down-scaling in shaping the specificity of an associative memory is identified.
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Affiliation(s)
- Carola I Radulescu
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Samuel J Barnes
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.
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10
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Wu CH, Ramos R, Katz DB, Turrigiano GG. Homeostatic synaptic scaling establishes the specificity of an associative memory. Curr Biol 2021; 31:2274-2285.e5. [PMID: 33798429 PMCID: PMC8187282 DOI: 10.1016/j.cub.2021.03.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Correlation-based (Hebbian) forms of synaptic plasticity are crucial for the initial encoding of associative memories but likely insufficient to enable the stable storage of multiple specific memories within neural circuits. Theoretical studies have suggested that homeostatic synaptic normalization rules provide an essential countervailing force that can stabilize and expand memory storage capacity. Although such homeostatic mechanisms have been identified and studied for decades, experimental evidence that they play an important role in associative memory is lacking. Here, we show that synaptic scaling, a widely studied form of homeostatic synaptic plasticity that globally renormalizes synaptic strengths, is dispensable for initial associative memory formation but crucial for the establishment of memory specificity. We used conditioned taste aversion (CTA) learning, a form of associative learning that relies on Hebbian mechanisms within gustatory cortex (GC), to show that animals conditioned to avoid saccharin initially generalized this aversion to other novel tastants. Specificity of the aversion to saccharin emerged slowly over a time course of many hours and was associated with synaptic scaling down of excitatory synapses onto conditioning-active neuronal ensembles within gustatory cortex. Blocking synaptic scaling down in the gustatory cortex enhanced the persistence of synaptic strength increases induced by conditioning and prolonged the duration of memory generalization. Taken together, these findings demonstrate that synaptic scaling is crucial for sculpting the specificity of an associative memory and suggest that the relative strengths of Hebbian and homeostatic plasticity can modulate the balance between stable memory formation and memory generalization.
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Affiliation(s)
- Chi-Hong Wu
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - Raul Ramos
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - Donald B Katz
- Department of Psychology, Brandeis University, Waltham, MA 02453, USA
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Compans B, Camus C, Kallergi E, Sposini S, Martineau M, Butler C, Kechkar A, Klaassen RV, Retailleau N, Sejnowski TJ, Smit AB, Sibarita JB, Bartol TM, Perrais D, Nikoletopoulou V, Choquet D, Hosy E. NMDAR-dependent long-term depression is associated with increased short term plasticity through autophagy mediated loss of PSD-95. Nat Commun 2021; 12:2849. [PMID: 33990590 PMCID: PMC8121912 DOI: 10.1038/s41467-021-23133-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 04/07/2021] [Indexed: 01/27/2023] Open
Abstract
Long-term depression (LTD) of synaptic strength can take multiple forms and contribute to circuit remodeling, memory encoding or erasure. The generic term LTD encompasses various induction pathways, including activation of NMDA, mGlu or P2X receptors. However, the associated specific molecular mechanisms and effects on synaptic physiology are still unclear. We here compare how NMDAR- or P2XR-dependent LTD affect synaptic nanoscale organization and function in rodents. While both LTDs are associated with a loss and reorganization of synaptic AMPARs, only NMDAR-dependent LTD induction triggers a profound reorganization of PSD-95. This modification, which requires the autophagy machinery to remove the T19-phosphorylated form of PSD-95 from synapses, leads to an increase in AMPAR surface mobility. We demonstrate that these post-synaptic changes that occur specifically during NMDAR-dependent LTD result in an increased short-term plasticity improving neuronal responsiveness of depressed synapses. Our results establish that P2XR- and NMDAR-mediated LTD are associated to functionally distinct forms of LTD.
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Affiliation(s)
- Benjamin Compans
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Come Camus
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Emmanouela Kallergi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Silvia Sposini
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Magalie Martineau
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Corey Butler
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Adel Kechkar
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Remco V Klaassen
- Department Molecular and Cellular Neurobiology, Amsterdam, HV, The Netherlands
| | - Natacha Retailleau
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Terrence J Sejnowski
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - August B Smit
- Department Molecular and Cellular Neurobiology, Amsterdam, HV, The Netherlands
| | - Jean-Baptiste Sibarita
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | - Thomas M Bartol
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - David Perrais
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
| | | | - Daniel Choquet
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, Bordeaux, France
| | - Eric Hosy
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France.
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12
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The aging mouse brain: cognition, connectivity and calcium. Cell Calcium 2021; 94:102358. [PMID: 33517250 DOI: 10.1016/j.ceca.2021.102358] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 02/08/2023]
Abstract
Aging is a complex process that differentially impacts multiple cognitive, sensory, neuronal and molecular processes. Technological innovations now allow for parallel investigation of neuronal circuit function, structure and molecular composition in the brain of awake behaving adult mice. Thus, mice have become a critical tool to better understand how aging impacts the brain. However, a more granular systems-based approach, which considers the impact of age on key features relating to neural processing, is required. Here, we review evidence probing the impact of age on the mouse brain. We focus on a range of processes relating to neuronal function, including cognitive abilities, sensory systems, synaptic plasticity and calcium regulation. Across many systems, we find evidence for prominent age-related dysregulation even before 12 months of age, suggesting that emerging age-related alterations can manifest by late adulthood. However, we also find reports suggesting that some processes are remarkably resilient to aging. The evidence suggests that aging does not drive a parallel, linear dysregulation of all systems, but instead impacts some processes earlier, and more severely, than others. We propose that capturing the more fine-scale emerging features of age-related vulnerability and resilience may provide better opportunities for the rejuvenation of the aged brain.
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13
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Lignani G, Baldelli P, Marra V. Homeostatic Plasticity in Epilepsy. Front Cell Neurosci 2020; 14:197. [PMID: 32676011 PMCID: PMC7333442 DOI: 10.3389/fncel.2020.00197] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/05/2020] [Indexed: 11/26/2022] Open
Abstract
In the healthy brain, neuronal excitability and synaptic strength are homeostatically regulated to keep neuronal network activity within physiological boundaries. Epilepsy is characterized by episodes of highly synchronized firing across in widespread neuronal populations, due to a failure in regulation of network activity. Here we consider epilepsy as a failure of homeostatic plasticity or as a maladaptive response to perturbations in the activity. How homeostatic compensation is involved in epileptogenic processes or in the chronic phase of epilepsy, is still debated. Although several theories have been proposed, there is relatively little experimental evidence to evaluate them. In this perspective, we will discuss recent results that shed light on the potential role of homeostatic plasticity in epilepsy. First, we will present some recent insights on how homeostatic compensations are probably active before and during epileptogenesis and how their actions are temporally regulated and closely dependent on the progression of pathology. Then, we will consider the dual role of transcriptional regulation during epileptogenesis, and finally, we will underline the importance of homeostatic plasticity in the context of therapeutic interventions for epilepsy. While classic pharmacological interventions may be counteracted by the epileptic brain to maintain its potentially dysfunctional set point, novel therapeutic approaches may provide the neuronal network with the tools necessary to restore its physiological balance.
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Affiliation(s)
- Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Vincenzo Marra
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
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14
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Lu W, Ai H, Xue F, Luan Y, Zhang B. The Noonan syndrome-associated D61G variant of the protein tyrosine phosphatase SHP2 prevents synaptic down-scaling. J Biol Chem 2020; 295:10023-10031. [PMID: 32499374 DOI: 10.1074/jbc.ra119.010331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 06/01/2020] [Indexed: 11/06/2022] Open
Abstract
Homeostatic scaling of the synapse, such as synaptic down-scaling, has been proposed to offset deleterious effects induced by sustained synaptic strength enhancement. Proper function and subcellular distribution of Src homology 2 domain-containing nonreceptor protein tyrosine phosphatase (SHP2) are required for synaptic plasticity. However, the role of SHP2 in synaptic down-scaling remains largely unknown. Here, using biochemical assays and cell-imaging techniques, we found that synaptic SHP2 levels are temporally regulated during synaptic down-scaling in cultured hippocampal neurons. Furthermore, we observed that a Noonan syndrome-associated mutation of SHP2, resulting in a D61G substitution, prevents synaptic down-scaling. We further show that this effect is due to an inability of the SHP2-D61G variant to properly disassociate from postsynaptic density protein 95, leading to impaired SHP2 dispersion from synaptic sites after synaptic down-scaling. Our findings reveal a molecular mechanism of the Noonan syndrome-associated genetic variant SHP2-D61G that contributes to deficient synaptic down-scaling.
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Affiliation(s)
- Wen Lu
- Department of Biochemistry and Molecular Biology, Hainan Medical University, Haikou, China.,Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, China
| | - Heng Ai
- Department of Physiology, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Fusheng Xue
- Zhejiang Key Laboratory of Organ Development and Regeneration, Institute of Life Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yifei Luan
- Department of Physiology, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Bin Zhang
- Zhejiang Key Laboratory of Organ Development and Regeneration, Institute of Life Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China
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15
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Luo S, Hou Y, Zhang Y, Ma T, Shao W, Xiao C. Adenosine A 2A Receptor Agonist PSB-0777 Modulates Synaptic Proteins and AMPA Receptor Expression in a Dose- and Time-Dependent Manner in Rat Primary Cortical Neurons. Biol Pharm Bull 2020; 43:1159-1171. [PMID: 32448843 DOI: 10.1248/bpb.b19-01007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulating synaptic formation and transmission is critical for the physiology and pathology of psychiatric disorders. The adenosine A2A receptor subtype has attracted widespread attention as a key regulator of neuropsychiatric activity, neuroprotection and injury. In this study, we systematically investigated the regulatory effects of a novel A2A receptor agonist, PSB-0777, on the expression of synaptic proteins and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors (AMPA receptors) at the cellular level in a time- and dose-dependent manner. After 30 min of high-dose PSB-0777 stimulation, the expression of Synapsin-1 (Syn-1), postsynaptic density protein 95 (PSD95), and AMPA receptors and the number of synapses were rapidly and significantly increased in rat primary cortical neurons compared with the control. Sustained elevation was found in the low and medium-dose groups after 24 h and 3 d of treatment. In contrast, after stimulation with PSB-0777 for 3 consecutive days, the expression of Syn-1 was decreased, and PSD95, AMPA receptors and the number of synapses were no longer increased in the high-dose group. Our study focuses on the detailed and systematic regulation of synaptic proteins and AMPA receptors by an A2A receptor agonist, PSB-0777, which may result in both beneficial and detrimental effects on neurotransmission and neuroprotection and may contribute to the pathophysiology of psychiatric disorders related to A2A receptors. These experimental data may contribute to understanding of the mechanisms for neuroprotective and therapeutic effect of A2A receptor agonists.
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Affiliation(s)
| | | | | | - Tengfei Ma
- Yunnan University, School of Life Sciences, Center for Life Sciences
| | - Wenping Shao
- First Affiliated Hospital of Kunming Medical University, Department of Medical Examination
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16
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Delgado JY. An Alternative Pin1 Binding and Isomerization Site in the N-Terminus Domain of PSD-95. Front Mol Neurosci 2020; 13:31. [PMID: 32256312 PMCID: PMC7094161 DOI: 10.3389/fnmol.2020.00031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 02/11/2020] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation-dependent peptidyl-prolyl cis-trans isomerization plays key roles in cell cycle progression, the pathogenesis of cancer, and age-related neurodegeneration. Most of our knowledge about the role of phosphorylation-dependent peptidyl-prolyl cis-trans isomerization and the enzyme catalyzing this reaction, the peptidyl-prolyl isomerase (Pin1), is largely limited to proteins not present in neurons. Only a handful of examples have shown that phosphorylation-dependent peptidyl-prolyl cis-trans isomerization, Pin1 binding, or Pin1-mediated peptidyl-prolyl cis-trans isomerization regulate proteins present at excitatory synapses. In this work, I confirm previous findings showing that Pin1 binds postsynaptic density protein-95 (PSD-95) and identify an alternative binding site in the phosphorylated N-terminus of the PSD-95. Pin1 associates via its WW domain with phosphorylated threonine (T19) and serine (S25) in the N-terminus domain of PSD-95 and this association alters the local conformation of PSD-95. Most importantly, I show that proline-directed phosphorylation of the N-terminus domain of PSD-95 alters the local conformation of this region. Therefore, proline-directed phosphorylation of the N-terminus of PSD-95, Pin1 association, and peptidyl-prolyl cis-trans isomerization may all play a role in excitatory synaptic function and synapse development.
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Affiliation(s)
- Jary Y Delgado
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
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17
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Delgado JY, Nall D, Selvin PR. Pin1 Binding to Phosphorylated PSD-95 Regulates the Number of Functional Excitatory Synapses. Front Mol Neurosci 2020; 13:10. [PMID: 32231520 PMCID: PMC7082786 DOI: 10.3389/fnmol.2020.00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/14/2020] [Indexed: 12/23/2022] Open
Abstract
The post-synaptic density protein 95 (PSD-95) plays a central role in excitatory synapse development and synaptic plasticity. Phosphorylation of the N-terminus of PSD-95 at threonine 19 (T19) and serine 25 (S25) decreases PSD-95 stability at synapses; however, a molecular mechanism linking PSD-95 phosphorylation to altered synaptic stability is lacking. Here, we show that phosphorylation of T19/S25 recruits the phosphorylation-dependent peptidyl-prolyl cis-trans isomerase (Pin1) and reduces the palmitoylation of Cysteine 3 and Cysteine 5 in PSD-95. This reduction in PSD-95 palmitoylation accounts for the observed loss in the number of dendritic PSD-95 clusters, the increased AMPAR mobility, and the decreased number of functional excitatory synapses. We find the effects of Pin1 overexpression were all rescued by manipulations aimed at increasing the levels of PSD-95 palmitoylation. Therefore, Pin1 is a key signaling molecule that regulates the stability of excitatory synapses and may participate in the destabilization of PSD-95 following the induction of synaptic plasticity.
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Affiliation(s)
- Jary Y. Delgado
- Department of Neurobiology, The University of Chicago, Chicago, IL, United States
| | - Duncan Nall
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana–Champaign, Urbana, IL, United States
| | - Paul R. Selvin
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana–Champaign, Urbana, IL, United States
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18
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Dürvanger Z, Harmat V. Structural Diversity in Calmodulin - Peptide Interactions. Curr Protein Pept Sci 2020; 20:1102-1111. [PMID: 31553290 DOI: 10.2174/1389203720666190925101937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/13/2019] [Accepted: 04/12/2019] [Indexed: 01/17/2023]
Abstract
Calmodulin (CaM) is a highly conserved eukaryotic Ca2+ sensor protein that is able to bind a large variety of target sequences without a defined consensus sequence. The recognition of this diverse target set allows CaM to take part in the regulation of several vital cell functions. To fully understand the structural basis of the regulation functions of CaM, the investigation of complexes of CaM and its targets is essential. In this minireview we give an outline of the different types of CaM - peptide complexes with 3D structure determined, also providing an overview of recently determined structures. We discuss factors defining the orientations of peptides within the complexes, as well as roles of anchoring residues. The emphasis is on complexes where multiple binding modes were found.
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Affiliation(s)
- Zsolt Dürvanger
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Protein Modelling Research Group, Budapest, Hungary
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19
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Activity Dependent and Independent Determinants of Synaptic Size Diversity. J Neurosci 2020; 40:2828-2848. [PMID: 32127494 DOI: 10.1523/jneurosci.2181-19.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/04/2020] [Accepted: 02/13/2020] [Indexed: 11/21/2022] Open
Abstract
The extraordinary diversity of excitatory synapse sizes is commonly attributed to activity-dependent processes that drive synaptic growth and diminution. Recent studies also point to activity-independent size fluctuations, possibly driven by innate synaptic molecule dynamics, as important generators of size diversity. To examine the contributions of activity-dependent and independent processes to excitatory synapse size diversity, we studied glutamatergic synapse size dynamics and diversification in cultured rat cortical neurons (both sexes), silenced from plating. We found that in networks with no history of activity whatsoever, synaptic size diversity was no less extensive than that observed in spontaneously active networks. Synapses in silenced networks were larger, size distributions were broader, yet these were rightward-skewed and similar in shape when scaled by mean synaptic size. Silencing reduced the magnitude of size fluctuations and weakened constraints on size distributions, yet these were sufficient to explain synaptic size diversity in silenced networks. Model-based exploration followed by experimental testing indicated that silencing-associated changes in innate molecular dynamics and fluctuation characteristics might negatively impact synaptic persistence, resulting in reduced synaptic numbers. This, in turn, would increase synaptic molecule availability, promote synaptic enlargement, and ultimately alter fluctuation characteristics. These findings suggest that activity-independent size fluctuations are sufficient to fully diversify glutamatergic synaptic sizes, with activity-dependent processes primarily setting the scale rather than the shape of size distributions. Moreover, they point to reciprocal relationships between synaptic size fluctuations, size distributions, and synaptic numbers mediated by the innate dynamics of synaptic molecules as they move in, out, and between synapses.SIGNIFICANCE STATEMENT Sizes of glutamatergic synapses vary tremendously, even when formed on the same neuron. This diversity is commonly thought to reflect the outcome of activity-dependent forms of synaptic plasticity, yet activity-independent processes might also play some part. Here we show that in neurons with no history of activity whatsoever, synaptic sizes are no less diverse. We show that this diversity is the product of activity-independent size fluctuations, which are sufficient to generate a full repertoire of synaptic sizes at correct proportions. By combining modeling and experimentation we expose reciprocal relationships between size fluctuations, synaptic sizes and synaptic counts, and show how these phenomena might be connected through the dynamics of synaptic molecules as they move in, out, and between synapses.
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20
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Zhang Y, Meng X, Jiao Z, Liu Y, Zhang X, Qu S. Generation of a Novel Mouse Model of Parkinson's Disease via Targeted Knockdown of Glutamate Transporter GLT-1 in the Substantia Nigra. ACS Chem Neurosci 2020; 11:406-417. [PMID: 31909584 DOI: 10.1021/acschemneuro.9b00609] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease that is characterized by pathological dopaminergic (DA) neuronal death and α-synuclein aggregation. Glutamate excitotoxicity is a well-established pathogenesis of PD that involves dysfunctional expression of glutamate transporters. Glutamate transporter-1 (GLT-1) is mainly responsible for clearance of glutamate at synapses, including DA synapses. However, the role of GLT-1 in the aberrant synaptic transmission in PD remains elusive. In the present study, we generated small-interfering RNAs (siRNAs) to knockdown GLT-1 expression in primary astrocytes, and we report that siRNA knockdown of astrocytic GLT-1 decreased postsynaptic density-95 (PSD-95) expression in neuron-astrocyte cocultures in vitro. Using adeno-associated viruses (AAVs) targeting GLT-1 short-hairpin RNA (shRNA) sequences with a glial fibrillary acidic protein (GFAP) promoter, we abolished astrocytic GLT-1 expression in the substantia nigra pars compacta (SNpc) of mice. We found that GLT-1 deficiency in the SNpc induced parkinsonian phenotypes in terms of progressive motor deficits and nigral DA neuronal death in mice. We also found that there were reactive astrocytes and microglia in the SNpc upon GLT-1 knockdown. Furthermore, we used RNA sequencing to determine altered gene expression patterns upon GLT-1 knockdown in the SNpc, which revealed that disrupted calcium signaling pathways may be responsible for GLT-1 deficiency-mediated DA neuronal death in the SNpc. Taken together, our findings provide evidence for a novel role of GLT-1 in parkinsonian phenotypes in mice, which may contribute to further elucidation of the mechanisms of PD pathogenesis.
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Affiliation(s)
- Yunlong Zhang
- Institute of Neuroscience
and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
- Shenzhen Research Institute of Xiamen University, Shenzhen 518000, China
| | - Xingjun Meng
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528300, China
| | - Zhigang Jiao
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528300, China
| | - Yan Liu
- Department of Traditional Chinese Medicine, Medical College, Xiamen University, Xiamen 361102, China
| | - Xiuping Zhang
- Teaching Center of Experimental Medicine, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shaogang Qu
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528300, China
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21
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Chowdhury D, Hell JW. Ca 2+/Calmodulin Binding to PSD-95 Downregulates Its Palmitoylation and AMPARs in Long-Term Depression. Front Synaptic Neurosci 2019; 11:6. [PMID: 30914943 PMCID: PMC6422948 DOI: 10.3389/fnsyn.2019.00006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/18/2019] [Indexed: 12/17/2022] Open
Abstract
AMPA-type glutamate receptors (AMPARs) are clustered into functional nanodomains at postsynaptic sites through anchorage by the scaffolding protein, postsynaptic density protein-95 (PSD-95). The synaptic abundance of AMPARs is dynamically controlled in various forms of synaptic plasticity. Removal of AMPARs from the synapse in long-term depression (LTD) requires mobilization of PSD-95 away from the synapse. The molecular mechanisms underlying PSD-95 dispersal from the synapse during LTD are not completely understood. Here we show that, following Ca2+ influx, binding of Ca2+/calmodulin (CaM) to PSD-95 triggers loss of synaptic PSD-95 as well as surface AMPARs during chemically induced LTD in cultured rat neurons. Our data suggest that a reduction in PSD-95 palmitoylation mediates the effect of Ca2+/CaM on PSD-95 synaptic levels during LTD. These findings reveal a novel molecular mechanism for synaptic AMPAR regulation in LTD.
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Affiliation(s)
- Dhrubajyoti Chowdhury
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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22
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Matt L, Kim K, Chowdhury D, Hell JW. Role of Palmitoylation of Postsynaptic Proteins in Promoting Synaptic Plasticity. Front Mol Neurosci 2019; 12:8. [PMID: 30766476 PMCID: PMC6365469 DOI: 10.3389/fnmol.2019.00008] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/10/2019] [Indexed: 12/19/2022] Open
Abstract
Many postsynaptic proteins undergo palmitoylation, the reversible attachment of the fatty acid palmitate to cysteine residues, which influences trafficking, localization, and protein interaction dynamics. Both palmitoylation by palmitoyl acyl transferases (PAT) and depalmitoylation by palmitoyl-protein thioesterases (PPT) is regulated in an activity-dependent, localized fashion. Recently, palmitoylation has received attention for its pivotal contribution to various forms of synaptic plasticity, the dynamic modulation of synaptic strength in response to neuronal activity. For instance, palmitoylation and depalmitoylation of the central postsynaptic scaffold protein postsynaptic density-95 (PSD-95) is important for synaptic plasticity. Here, we provide a comprehensive review of studies linking palmitoylation of postsynaptic proteins to synaptic plasticity.
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Affiliation(s)
- Lucas Matt
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Karam Kim
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Dhrubajyoti Chowdhury
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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23
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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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24
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Patriarchi T, Buonarati OR, Hell JW. Postsynaptic localization and regulation of AMPA receptors and Cav1.2 by β2 adrenergic receptor/PKA and Ca 2+/CaMKII signaling. EMBO J 2018; 37:e99771. [PMID: 30249603 PMCID: PMC6187224 DOI: 10.15252/embj.201899771] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/25/2018] [Accepted: 08/17/2018] [Indexed: 11/09/2022] Open
Abstract
The synapse transmits, processes, and stores data within its tiny space. Effective and specific signaling requires precise alignment of the relevant components. This review examines current insights into mechanisms of AMPAR and NMDAR localization by PSD-95 and their spatial distribution at postsynaptic sites to illuminate the structural and functional framework of postsynaptic signaling. It subsequently delineates how β2 adrenergic receptor (β2 AR) signaling via adenylyl cyclase and the cAMP-dependent protein kinase PKA is organized within nanodomains. Here, we discuss targeting of β2 AR, adenylyl cyclase, and PKA to defined signaling complexes at postsynaptic sites, i.e., AMPARs and the L-type Ca2+ channel Cav1.2, and other subcellular surface localizations, the role of A kinase anchor proteins, the physiological relevance of the spatial restriction of corresponding signaling, and their interplay with signal transduction by the Ca2+- and calmodulin-dependent kinase CaMKII How localized and specific signaling by cAMP occurs is a central cellular question. The dendritic spine constitutes an ideal paradigm for elucidating the dimensions of spatially restricted signaling because of their small size and defined protein composition.
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MESH Headings
- Animals
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/physiology
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Cyclic AMP-Dependent Protein Kinases/genetics
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Humans
- Receptors, AMPA/genetics
- Receptors, AMPA/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Synapses/genetics
- Synapses/metabolism
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Affiliation(s)
- Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, CA, USA
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, USA
| | | | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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25
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Louros SR, Caldeira GL, Carvalho AL. Stargazin Dephosphorylation Mediates Homeostatic Synaptic Downscaling of Excitatory Synapses. Front Mol Neurosci 2018; 11:328. [PMID: 30271322 PMCID: PMC6146028 DOI: 10.3389/fnmol.2018.00328] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 08/24/2018] [Indexed: 11/13/2022] Open
Abstract
Synaptic scaling is a form of homeostatic plasticity that is critical for maintaining neuronal activity within a dynamic range, and which alters synaptic strength through changes in postsynaptic AMPA-type glutamate receptors. Homeostatic scaling down of excitatory synapses has been shown to occur during sleep, and to contribute to synapse remodeling and memory consolidation, but the underlying mechanisms are only partially known. Here, we report that synaptic downscaling in cortical neurons is accompanied by dephosphorylation of the transmembrane AMPA receptor regulatory protein stargazin, and by an increase in its cell surface mobility. The changes in stargazin surface diffusion were paralleled by an increase in the mobility of GluA1-containing AMPA receptors at synaptic sites. In addition, stargazin dephosphorylation was required for the downregulation of surface levels of GluA1-containing AMPA receptors promoted by chronic elevation of neuronal activity, specifically by mediating the interaction with the adaptor proteins AP-2 and AP-3A. Disruption of the stargazin-AP-3A interaction was sufficient to prevent the decrease in cell surface GluA1-AMPA receptor levels associated with chronically enhanced synaptic activity, suggesting that scaling down is accomplished through decreased AMPA receptor recycling and enhanced lysosomal degradation. Thus, synaptic downscaling is associated with both increased stargazin and AMPA receptor cell surface diffusion, as well as with stargazin-mediated AMPA receptor endocytosis and lysosomal degradation.
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Affiliation(s)
- Susana R Louros
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Gladys L Caldeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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26
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Matt L, Kim K, Hergarden AC, Patriarchi T, Malik ZA, Park DK, Chowdhury D, Buonarati OR, Henderson PB, Gökçek Saraç Ç, Zhang Y, Mohapatra D, Horne MC, Ames JB, Hell JW. α-Actinin Anchors PSD-95 at Postsynaptic Sites. Neuron 2018; 97:1094-1109.e9. [PMID: 29429936 PMCID: PMC5963734 DOI: 10.1016/j.neuron.2018.01.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/10/2017] [Accepted: 01/17/2018] [Indexed: 12/17/2022]
Abstract
Despite the central role PSD-95 plays in anchoring postsynaptic AMPARs, how PSD-95 itself is tethered to postsynaptic sites is not well understood. Here we show that the F-actin binding protein α-actinin binds to the very N terminus of PSD-95. Knockdown (KD) of α-actinin phenocopies KD of PSD-95. Mutating lysine at position 10 or lysine at position 11 of PSD-95 to glutamate, or glutamate at position 53 or glutamate and aspartate at positions 213 and 217 of α-actinin, respectively, to lysine impairs, in parallel, PSD-95 binding to α-actinin and postsynaptic localization of PSD-95 and AMPARs. These experiments identify α-actinin as a critical PSD-95 anchor tethering the AMPAR-PSD-95 complex to postsynaptic sites.
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Affiliation(s)
- Lucas Matt
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Karam Kim
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Anne C Hergarden
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Zulfiqar A Malik
- Department of Pharmacology, University of California, Davis, Davis, CA, USA; Department of Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Deborah K Park
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | | | - Olivia R Buonarati
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Peter B Henderson
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Çiğdem Gökçek Saraç
- Department of Pharmacology, University of California, Davis, Davis, CA, USA; Department of Biomedical Engineering, Faculty of Engineering, Akdeniz University, Antalya, Turkey
| | - Yonghong Zhang
- Department of Chemistry, University of California, Davis, Davis, CA, USA
| | - Durga Mohapatra
- Department of Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, Davis, CA, USA; Department of Pharmacology, University of Iowa, Iowa City, IA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA, USA; Department of Pharmacology, University of Iowa, Iowa City, IA, USA.
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27
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Chowdhury D, Hell JW. Homeostatic synaptic scaling: molecular regulators of synaptic AMPA-type glutamate receptors. F1000Res 2018; 7:234. [PMID: 29560257 PMCID: PMC5832907 DOI: 10.12688/f1000research.13561.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/20/2018] [Indexed: 01/31/2023] Open
Abstract
The ability of neurons and circuits to maintain their excitability and activity levels within the appropriate dynamic range by homeostatic mechanisms is fundamental for brain function. Neuronal hyperactivity, for instance, could cause seizures. One such homeostatic process is synaptic scaling, also known as synaptic homeostasis. It involves a negative feedback process by which neurons adjust (scale) their postsynaptic strength over their whole synapse population to compensate for increased or decreased overall input thereby preventing neuronal hyper- or hypoactivity that could otherwise result in neuronal network dysfunction. While synaptic scaling is well-established and critical, our understanding of the underlying molecular mechanisms is still in its infancy. Homeostatic adaptation of synaptic strength is achieved through upregulation (upscaling) or downregulation (downscaling) of the functional availability of AMPA-type glutamate receptors (AMPARs) at postsynaptic sites. Understanding how synaptic AMPARs are modulated in response to alterations in overall neuronal activity is essential to gain valuable insights into how neuronal networks adapt to changes in their environment, as well as the genesis of an array of neurological disorders. Here we discuss the key molecular mechanisms that have been implicated in tuning the synaptic abundance of postsynaptic AMPARs in order to maintain synaptic homeostasis.
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Affiliation(s)
| | - Johannes W Hell
- Department of Pharmacology, University of California Davis, Davis, California, USA
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28
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Chowdhury D, Turner M, Patriarchi T, Hergarden AC, Anderson D, Zhang Y, Sun J, Chen CY, Ames JB, Hell JW. Ca 2+/calmodulin binding to PSD-95 mediates homeostatic synaptic scaling down. EMBO J 2017; 37:122-138. [PMID: 29118000 DOI: 10.15252/embj.201695829] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 09/07/2017] [Accepted: 10/02/2017] [Indexed: 11/09/2022] Open
Abstract
Postsynaptic density protein-95 (PSD-95) localizes AMPA-type glutamate receptors (AMPARs) to postsynaptic sites of glutamatergic synapses. Its postsynaptic displacement is necessary for loss of AMPARs during homeostatic scaling down of synapses. Here, we demonstrate that upon Ca2+ influx, Ca2+/calmodulin (Ca2+/CaM) binding to the N-terminus of PSD-95 mediates postsynaptic loss of PSD-95 and AMPARs during homeostatic scaling down. Our NMR structural analysis identified E17 within the PSD-95 N-terminus as important for binding to Ca2+/CaM by interacting with R126 on CaM. Mutating E17 to R prevented homeostatic scaling down in primary hippocampal neurons, which is rescued via charge inversion by ectopic expression of CaMR126E, as determined by analysis of miniature excitatory postsynaptic currents. Accordingly, increased binding of Ca2+/CaM to PSD-95 induced by a chronic increase in Ca2+ influx is a critical molecular event in homeostatic downscaling of glutamatergic synaptic transmission.
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Affiliation(s)
| | - Matthew Turner
- Department of Chemistry, University of California, Davis, CA, USA
| | | | - Anne C Hergarden
- Department of Pharmacology, University of California, Davis, CA, USA
| | - David Anderson
- Department of Chemistry, University of California, Davis, CA, USA
| | - Yonghong Zhang
- Department of Chemistry, University of Texas, Edinburgh, TX, USA
| | - Junqing Sun
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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