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Wang C, Zhai J, Chen Y. Novel KCNQ2 missense variant expands the genotype spectrum of DEE7. Neurol Sci 2024:10.1007/s10072-024-07655-w. [PMID: 38880853 DOI: 10.1007/s10072-024-07655-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 06/05/2024] [Indexed: 06/18/2024]
Abstract
BACKGROUND KCNQ is a voltage-gated K + channel that controls neuronal excitability and is mutated in epilepsy and autism spectrum disorder (ASD). We focus on the KV7.2 voltage-gated potassium channel gene (KCNQ2), which is known for its association with developmental delay and various seizures (including self-limited benign familial neonatal epilepsy and epileptic encephalopathy). But the pathogenicity of many variants remains unproven, potentially leading to misinterpretation of their functional consequences. METHODS In this study, we studied a patient who visited Nanhua Hospital. Targeted next-generation sequencing and Sanger sequencing were used to identify the pathogenic variants. Meanwhile, computational models, including hydrogen bonding and docking analyses, suggest that variants cause functional impairment. In addition, functional validation was performed in the drosophila to further evaluate the missense variant in the KCNQ2 gene as the cause of this patient. RESULTS A new missense variant in the KCNQ2 gene was identified: NM_172107.4:c.1007C > A(p.ALa336Glu), which resulted in the change from alanine to glutamate at amino acid position 336 in the KCNQ2 gene. After computational modeling, including hydrogen bond analysis and docking analysis, it is indicated that the variants cause functional impairment. Furthermore, RNAi-mediated KCNQ knockout in flies led to the onset of epileptic behavior, lifespan and climbing capacity were affected, expression of the normal human KCNQ2 rescues the in flies RNAi-mediated KCNQ knockout behavioral abnormalities. CONCLUSION Our findings expands the genetic profile of KCNQ2 and enhances the genotype - phenotype link.
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Affiliation(s)
- Chao Wang
- Department of Neurology, the Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - JinXia Zhai
- Department of Neurology, the Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - YongJun Chen
- Department of Neurology, the Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China.
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2
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Cao YY, Wu LL, Li XN, Yuan YL, Zhao WW, Qi JX, Zhao XY, Ward N, Wang J. Molecular Mechanisms of AMPA Receptor Trafficking in the Nervous System. Int J Mol Sci 2023; 25:111. [PMID: 38203282 PMCID: PMC10779435 DOI: 10.3390/ijms25010111] [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: 11/24/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Synaptic plasticity enhances or reduces connections between neurons, affecting learning and memory. Postsynaptic AMPARs mediate greater than 90% of the rapid excitatory synaptic transmission in glutamatergic neurons. The number and subunit composition of AMPARs are fundamental to synaptic plasticity and the formation of entire neural networks. Accordingly, the insertion and functionalization of AMPARs at the postsynaptic membrane have become a core issue related to neural circuit formation and information processing in the central nervous system. In this review, we summarize current knowledge regarding the related mechanisms of AMPAR expression and trafficking. The proteins related to AMPAR trafficking are discussed in detail, including vesicle-related proteins, cytoskeletal proteins, synaptic proteins, and protein kinases. Furthermore, significant emphasis was placed on the pivotal role of the actin cytoskeleton, which spans throughout the entire transport process in AMPAR transport, indicating that the actin cytoskeleton may serve as a fundamental basis for AMPAR trafficking. Additionally, we summarize the proteases involved in AMPAR post-translational modifications. Moreover, we provide an overview of AMPAR transport and localization to the postsynaptic membrane. Understanding the assembly, trafficking, and dynamic synaptic expression mechanisms of AMPAR may provide valuable insights into the cognitive decline associated with neurodegenerative diseases.
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Affiliation(s)
- Yi-Yang Cao
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Ling-Ling Wu
- School of Medicine, Shanghai University, Shanghai 200444, China;
| | - Xiao-Nan Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Yu-Lian Yuan
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Wan-Wei Zhao
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Jing-Xuan Qi
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Xu-Yu Zhao
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
| | - Natalie Ward
- Medical Laboratory, Exceptional Community Hospital, 19060 N John Wayne Pkwy, Maricopa, AZ 85139, USA;
| | - Jiao Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (Y.-Y.C.); (X.-N.L.); (Y.-L.Y.); (W.-W.Z.); (J.-X.Q.); (X.-Y.Z.)
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3
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Liu Z, Krstic A, Neve A, Casalou C, Rauch N, Wynne K, Cassidy H, McCann A, Kavanagh E, McCann B, Blanco A, Rauch J, Kolch W. Kinase Suppressor of RAS 1 (KSR1) Maintains the Transformed Phenotype of BRAFV600E Mutant Human Melanoma Cells. Int J Mol Sci 2023; 24:11821. [PMID: 37511580 PMCID: PMC10380721 DOI: 10.3390/ijms241411821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Kinase Suppressor of RAS 1 (KSR1) is a scaffolding protein for the RAS-RAF-MEK-ERK pathway, which is one of the most frequently altered pathways in human cancers. Previous results have shown that KSR1 has a critical role in mutant RAS-mediated transformation. Here, we examined the role of KSR1 in mutant BRAF transformation. We used CRISPR/Cas9 to knock out KSR1 in a BRAFV600E-transformed melanoma cell line. KSR1 loss produced a complex phenotype characterised by impaired proliferation, cell cycle defects, decreased transformation, decreased invasive migration, increased cellular senescence, and increased apoptosis. To decipher this phenotype, we used a combination of proteomic ERK substrate profiling, global protein expression profiling, and biochemical validation assays. The results suggest that KSR1 directs ERK to phosphorylate substrates that have a critical role in ensuring cell survival. The results further indicate that KSR1 loss induces the activation of p38 Mitogen-Activated Protein Kinase (MAPK) and subsequent cell cycle aberrations and senescence. In summary, KSR1 function plays a key role in oncogenic BRAF transformation.
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Affiliation(s)
- Zhi Liu
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Aleksandar Krstic
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Ashish Neve
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Cristina Casalou
- Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Nora Rauch
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Kieran Wynne
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Hilary Cassidy
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
- School of Biomolecular & Biomedical Science, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Amanda McCann
- School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
- Conway Institute, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Emma Kavanagh
- School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Brendan McCann
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Alfonso Blanco
- Conway Institute, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Jens Rauch
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
- School of Biomolecular & Biomedical Science, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Walter Kolch
- Systems Biology Ireland (SBI), School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
- School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland
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4
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Gu J, Ke P, Guo H, Liu J, Liu Y, Tian X, Huang Z, Xu X, Xu D, Ma Y, Wang X, Xiao F. KCTD13-mediated ubiquitination and degradation of GluN1 regulates excitatory synaptic transmission and seizure susceptibility. Cell Death Differ 2023; 30:1726-1741. [PMID: 37142655 PMCID: PMC10307852 DOI: 10.1038/s41418-023-01174-5] [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: 09/27/2022] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is the most common and severe form of epilepsy in adults; however, its underlying pathomechanisms remain elusive. Dysregulation of ubiquitination is increasingly recognized to contribute to the development and maintenance of epilepsy. Herein, we observed for the first time that potassium channel tetramerization domain containing 13 (KCTD13) protein, a substrate-specific adapter for cullin3-based E3 ubiquitin ligase, was markedly down-regulated in the brain tissue of patients with TLE. In a TLE mouse model, the protein expression of KCTD13 dynamically changed during epileptogenesis. Knockdown of KCTD13 in the mouse hippocampus significantly enhanced seizure susceptibility and severity, whereas overexpression of KCTD13 showed the opposite effect. Mechanistically, GluN1, an obligatory subunit of N-methyl-D-aspartic acid receptors (NMDARs), was identified as a potential substrate protein of KCTD13. Further investigation revealed that KCTD13 facilitates lysine-48-linked polyubiquitination of GluN1 and its degradation through the ubiquitin-proteasome pathway. Besides, the lysine residue 860 of GluN1 is the main ubiquitin site. Importantly, dysregulation of KCTD13 affected membrane expression of glutamate receptors and impaired glutamate synaptic transmission. Systemic administration of the NMDAR inhibitor memantine significantly rescued the epileptic phenotype aggravated by KCTD13 knockdown. In conclusion, our results demonstrated an unrecognized pathway of KCTD13-GluN1 in epilepsy, suggesting KCTD13 as a potential neuroprotective therapeutic target for epilepsy.
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Affiliation(s)
- Juan Gu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
- Department of Neurology, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Pingyang Ke
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Haokun Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Jing Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yan Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xin Tian
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 100191, Beijing, China
| | - Xin Xu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Demei Xu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yuanlin Ma
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.
| | - Fei Xiao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.
- Institute for Brain Science and Disease of Chongqing Medical University, Chongqing, 400016, China.
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5
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN inhibits dopamine D1 receptor-mediated seizure activity via DARPP-32 serine 97 dephosphorylation in the mouse hippocampus. Neuropharmacology 2023; 228:109462. [PMID: 36792029 DOI: 10.1016/j.neuropharm.2023.109462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/31/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023]
Abstract
Dopamine plays a central role in the regulation of psychomotor functions in the brain. Furthermore, the dopaminergic system is involved in the ictogenesis in human patients and animal models of epilepsy. Dopamine and cAMP-regulated phosphoprotein, 32 kDa (DARPP-32) plays an important role in the regulation of interactions between dopamine and glutamate receptors in neurons. Indeed, SKF 83822 (a specific D1 receptor agonist) facilitates DARPP-32-mediated protein phosphatase 1 (PP1) inhibition leading to the increase in phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR), which potentiates channel activities and currents and thereby generates seizure activity. In the present study, we found that pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN), a selective phosphatase for serine (S) residues, attenuated seizure susceptibility in response to SKF 83822 by dephosphorylating DARPP-32 S97 site. Similarly, inhibition of DARPP-32 S97 phosphorylation by 2-[4,5,6,7-Tetrabromo-2-(dimethylamino)-1H-benzo[d]imidazole-1-yl]acetic acid (TMCB; a selective casein kinase 2 inhibitor) attenuated SKF 83822-induced seizure activity. These inhibitory effects of PLPP/CIN and TMCB were relevant to the regulations of DARPP-32-PP1-AMPAR signaling pathway. Therefore, our findings suggest that PLPP/CIN may be a modulator in dopaminergic neurotransmission as well as glutamatergic systems, and that the PLPP/CIN-mediated DARPP-32 regulation may be one of the potential therapeutic targets for medication of seizure or epilepsy induced by D1 receptor hyperactivation.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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6
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated NF2 S10 dephosphorylation distinctly regulates kainate-induced seizure susceptibility and neuronal death through PAK1-NF-κB-COX-2-PTGES2 signaling pathway. J Neuroinflammation 2023; 20:99. [PMID: 37118736 PMCID: PMC10141957 DOI: 10.1186/s12974-023-02788-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/23/2023] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) selectively dephosphorylates serine (S) 10 site on neurofibromin 2 (NF2, also known as merlin (moesin-ezrin-radixin-like protein) or schwannomin). p21-activated kinase 1 (PAK1) is a serine/threonine protein kinase, which is involved in synaptic activity and plasticity in neurons. NF2 and PAK1 reciprocally regulate each other in a positive feedback manner. Thus, the aim of the present study is to investigate the effects of PLPP/CIN-mediated NF2 S10 dephosphorylation on PAK1-related signaling pathways under physiological and neuroinflammatory conditions, which are largely unknown. METHODS After kainate (KA) injection in wild-type, PLPP/CIN-/- and PLPP/CINTg mice, seizure susceptibility, PAK1 S204 autophosphorylation, nuclear factor-κB (NF-κB) p65 S276 phosphorylation, cyclooxygenase-2 (COX-2) upregulation, prostaglandin E synthase 2 (PTGES2) induction and neuronal damage were measured. The effects of 1,1'-dithiodi-2-naphthtol (IPA-3, a selective inhibitor of PAK1) pretreatment on these responses to KA were also validated. RESULTS PLPP/CIN overexpression increased PAK1 S204 autophosphorylation concomitant with the enhanced NF2 S10 dephosphorylation in hippocampal neurons under physiological condition. Following KA treatment, PLPP/CIN overexpression delayed the seizure on-set and accelerated PAK1 S204 phosphorylation, NF-κB p65 S276 phosphorylation, COX-2 upregulation and PTGES2 induction, which were ameliorated by PLPP/CIN deletion or IPA-3. Furthermore, IPA-3 pretreatment shortened the latency of seizure on-set without affecting seizure severity (intensity) and ameliorated CA3 neuronal death induced by KA. CONCLUSIONS These findings indicate that PLPP/CIN may regulate seizure susceptibility (the latency of seizure on-set) and CA3 neuronal death in response to KA through NF2-PAK1-NF-κB-COX-2-PTGES2 signaling pathway.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea.
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The role of post-translational modifications in synaptic AMPA receptor activity. Biochem Soc Trans 2023; 51:315-330. [PMID: 36629507 DOI: 10.1042/bst20220827] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
AMPA-type receptors for the neurotransmitter glutamate are very dynamic entities, and changes in their synaptic abundance underlie different forms of synaptic plasticity, including long-term synaptic potentiation (LTP), long-term depression (LTD) and homeostatic scaling. The different AMPA receptor subunits (GluA1-GluA4) share a common modular structure and membrane topology, and their intracellular C-terminus tail is responsible for the interaction with intracellular proteins important in receptor trafficking. The latter sequence differs between subunits and contains most sites for post-translational modifications of the receptors, including phosphorylation, O-GlcNAcylation, ubiquitination, acetylation, palmitoylation and nitrosylation, which affect differentially the various subunits. Considering that each single subunit may undergo modifications in multiple sites, and that AMPA receptors may be formed by the assembly of different subunits, this creates multiple layers of regulation of the receptors with impact in synaptic function and plasticity. This review discusses the diversity of mechanisms involved in the post-translational modification of AMPA receptor subunits, and their impact on the subcellular distribution and synaptic activity of the receptors.
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Bencsik N, Oueslati Morales CO, Hausser A, Schlett K. Endocytosis of AMPA receptors: Role in neurological conditions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:59-97. [PMID: 36813366 DOI: 10.1016/bs.pmbts.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AMPA receptors are glutamate-gated ion channels, present in a wide range of neuron types and in glial cells. Their main role is to mediate fast excitatory synaptic transmission, and therefore, they are critical for normal brain function. In neurons, AMPA receptors undergo constitutive and activity-dependent trafficking between the synaptic, extrasynaptic and intracellular pools. The kinetics of AMPA receptor trafficking is crucial for the precise functioning of both individual neurons and neural networks involved in information processing and learning. Many of the neurological diseases evoked by neurodevelopmental and neurodegenerative malfunctions or traumatic injuries are caused by impaired synaptic function in the central nervous system. For example, attention-deficit/hyperactivity disorder (ADHD), Alzheimer's disease (AD), tumors, seizures, ischemic strokes, and traumatic brain injury are all characterized by impaired glutamate homeostasis and associated neuronal death, typically caused by excitotoxicity. Given the important role of AMPA receptors in neuronal function, it is not surprising that perturbations in AMPA receptor trafficking are associated with these neurological disorders. In this book chapter, we will first introduce the structure, physiology and synthesis of AMPA receptors, followed by an in-depth description of the molecular mechanisms that control AMPA receptor endocytosis and surface levels under basal conditions or synaptic plasticity. Finally, we will discuss how impairments in AMPA receptor trafficking, particularly endocytosis, contribute to the pathophysiology of various neurological disorders and what efforts are being made to therapeutically target this process.
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Affiliation(s)
- Norbert Bencsik
- Neuronal Cell Biology Research Group, Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Carlos Omar Oueslati Morales
- Membrane Trafficking and Signalling Group, Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
| | - Angelika Hausser
- Membrane Trafficking and Signalling Group, Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany; Stuttgart Research Center Systems Biology, University of Stuttgart, Stuttgart, Germany
| | - Katalin Schlett
- Neuronal Cell Biology Research Group, Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary.
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9
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated DARPP-32 serine 97 dephosphorylation delays the seizure onset in response to kainic acid in the mouse hippocampus. Neuropharmacology 2022; 219:109238. [PMID: 36055413 DOI: 10.1016/j.neuropharm.2022.109238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022]
Abstract
Dopamine and cAMP-regulated phosphoprotein, 32 kDa (DARPP-32)-mediated protein phosphatase 1 (PP1) inhibition leads to the increase in phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR), which potentiates channel activity and current and thereby may facilitate seizure activity. In the present study, we found that pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) transiently dephosphorylated DARPP-32 serine (S) 97 site in the early time window, and casein kinase 2 (CK2) subsequently phosphorylated this site in the later time points after kainic acid (KA) injection, which increased the latency of seizure onset in response to KA, but exacerbated the intensity (severity), duration and progression of seizures. TMCB (a CK2 inhibitor) delayed the seizure onset in response to KA, concomitant with the reduced DARPP-32 S97 phosphorylation. Therefore, our findings suggest that PLPP/CIN may play an important role in the latency of seizure onset via DARPP-32-PP1-AMPAR signaling pathway, and may be one of the potential therapeutic targets for medication of seizure or epilepsy.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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Kim JE, Lee DS, Park H, Kim TH, Kang TC. AMPA Receptor Antagonists Facilitate NEDD4-2-Mediated GRIA1 Ubiquitination by Regulating PP2B-ERK1/2-SGK1 Pathway in Chronic Epilepsy Rats. Biomedicines 2021; 9:biomedicines9081069. [PMID: 34440273 PMCID: PMC8391511 DOI: 10.3390/biomedicines9081069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/12/2021] [Accepted: 08/19/2021] [Indexed: 11/16/2022] Open
Abstract
The neural precursor cell expressed by developmentally downregulated gene 4-2 (NEDD4-2) is a ubiquitin E3 ligase that has a high affinity toward binding and ubiquitinating glutamate ionotropic receptor α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) type subunit 1 (GRIA1, also referred to GluR1 or GluA1). Since dysregulation of GRIA1 surface expression is relevant to the responsiveness to AMPA receptor (AMPAR) antagonists (perampanel and GYKI 52466) in chronic epilepsy rats, it is likely that NEDD4-2 may be involved in the pathogenesis of intractable epilepsy. However, the role of NEDD4-2-mediated GRIA1 ubiquitination in refractory seizures to AMPAR antagonists is still unknown. In the present study, both AMPAR antagonists recovered the impaired GRIA1 ubiquitination by regulating protein phosphatase 2B (PP2B)-extracellular signal-regulated kinase 1/2 (ERK1/2)-serum and glucocorticoid-regulated kinase 1 (SGK1)-NEDD4-2 signaling pathway in responders (whose seizure activities are responsive to AMPAR), but not non-responders (whose seizure activities were uncontrolled by AMPAR antagonists). In addition, cyclosporin A (CsA, a PP2B inhibitor) co-treatment improved the effects of AMPAR antagonists in non-responders, independent of AKT signaling pathway. Therefore, our findings suggest that dysregulation of PP2B-ERK1/2-SGK1-NEDD4-2-mediated GRIA1 ubiquitination may be responsible for refractory seizures and that this pathway may be a potential therapeutic target for improving the treatment of intractable epilepsy in response to AMPAR antagonists.
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Affiliation(s)
- Ji-Eun Kim
- Correspondence: (J.-E.K.); (T.-C.K.); Tel.: +82-33-248-2522 (J.-E.K.); +82-33-248-2524 (T.-C.K.); Fax: +82-33-248-2525 (J.-E.K. & T.-C.K.)
| | | | | | | | - Tae-Cheon Kang
- Correspondence: (J.-E.K.); (T.-C.K.); Tel.: +82-33-248-2522 (J.-E.K.); +82-33-248-2524 (T.-C.K.); Fax: +82-33-248-2525 (J.-E.K. & T.-C.K.)
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11
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Historical perspective and progress on protein ubiquitination at glutamatergic synapses. Neuropharmacology 2021; 196:108690. [PMID: 34197891 DOI: 10.1016/j.neuropharm.2021.108690] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/07/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
Transcription-translation coupling leads to the production of proteins that are key for controlling essential neuronal processes that include neuronal development and changes in synaptic strength. Although these events have been a prevailing theme in neuroscience, the regulation of proteins via posttranslational signaling pathways are equally relevant for these neuronal processes. Ubiquitin is one type of posttranslational modification that covalently attaches to its targets/substrates. Ubiquitination of proteins play a key role in multiple signaling pathways, the predominant being removal of its substrates by a large molecular machine called the proteasome. Here, I review 40 years of progress on ubiquitination in the nervous system at glutamatergic synapses focusing on axon pathfinding, synapse formation, presynaptic release, dendritic spine formation, and regulation of postsynaptic glutamate receptors. Finally, I elucidate emerging themes in ubiquitin biology that may challenge our current understanding of ubiquitin signaling in the nervous system.
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12
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PLPP/CIN-mediated NF2-serine 10 dephosphorylation regulates F-actin stability and Mdm2 degradation in an activity-dependent manner. Cell Death Dis 2021; 12:37. [PMID: 33414453 PMCID: PMC7791067 DOI: 10.1038/s41419-020-03325-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/17/2022]
Abstract
Neurofibromin 2 (NF2, also known as merlin) is a tumor suppressor protein encoded by the neurofibromatosis type 2 gene NF2. NF2 is also an actin-binding protein that functions in an intrinsic signaling network critical for actin dynamics. Although protein kinase A (PKA)-mediated NF2-serin (S) 10 phosphorylation stabilizes filamentous actin (F-actin), the underlying mechanisms of NF2-S10 dephosphorylation and the role of NF2 in seizures have been elusive. Here, we demonstrate that pyridoxal-5′-phosphate phosphatase/chronophin (PLPP/CIN) dephosphorylated NF2-S10 site as well as cofilin-S3 site. In addition, NF2-S10 dephosphorylation reversely regulated murine double minute-2 (Mdm2) and postsynaptic density 95 (PSD95) degradations in an activity-dependent manner, which increased seizure intensity and its progression in response to kainic acid (KA). In addition, NF2 knockdown facilitated seizure intensity and its progress through F-actin instability independent of cofilin-mediated actin dynamics. Therefore, we suggest that PLPP/CIN may be a potential therapeutic target for epileptogenesis and NF2-associated diseases.
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13
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Eagleman DE, Zhu J, Liu DC, Seimetz J, Kalsotra A, Tsai NP. Unbiased proteomic screening identifies a novel role for the E3 ubiquitin ligase Nedd4-2 in translational suppression during ER stress. J Neurochem 2020; 157:1809-1820. [PMID: 33064840 DOI: 10.1111/jnc.15219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/11/2020] [Accepted: 09/30/2020] [Indexed: 01/15/2023]
Abstract
Endoplasmic reticulum (ER) stress occurs when protein folding or maturation is disrupted. A malfunction in the ER stress response can lead to cell death and has been observed in many neurological diseases. However, how the ER stress response is regulated in neuronal cells remains largely unclear. Here, we studied an E3 ubiquitin ligase named neural precursor cell expressed developmentally down-regulated protein 4-like (Nedd4-2). Nedd4-2 is highly expressed in the brain and has a high affinity toward ubiquitinating membrane-bound proteins. We first utilized unbiased proteomic profiling with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) of isolated membrane fractions from mouse whole brains to identify novel targets of Nedd4-2. Through this screen, we found that the expression and ubiquitination of ribosomal proteins are regulated by Nedd4-2 and we confirmed an association between Nedd4-2 and ribosomes through ribosome sedimentation and polysome profiling. Further, we utilized immunoprecipitation and western blotting to show that induction of ER stress promotes an association between Nedd4-2 and ribosomal proteins, which is mediated through dephosphorylation of Nedd4-2 at serine-342. This increased interaction between Nedd4-2 and ribosomal proteins in turn mediates ER stress-associated translational suppression. In summary, the results of this study demonstrate a novel regulatory mechanism underlying the ER stress response and a novel function of Nedd4-2 in translational control. Our findings may shed light on neurological diseases in which the ER stress response or the function of Nedd4-2 is dysregulated.
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Affiliation(s)
- Daphne E Eagleman
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jiuhe Zhu
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Dai-Chi Liu
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Joseph Seimetz
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Auinash Kalsotra
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Carl R.Woese Institute of Genomic Biology, University of Illinois, Champaign, IL, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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P2 × 7 Receptor Inhibits Astroglial Autophagy via Regulating FAK- and PHLPP1/2-Mediated AKT-S473 Phosphorylation Following Kainic Acid-Induced Seizures. Int J Mol Sci 2020; 21:ijms21186476. [PMID: 32899862 PMCID: PMC7555659 DOI: 10.3390/ijms21186476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 12/31/2022] Open
Abstract
Recently, we have reported that blockade/deletion of P2X7 receptor (P2X7R), an ATP-gated ion channel, exacerbates heat shock protein 25 (HSP25)-mediated astroglial autophagy (clasmatodendrosis) following kainic acid (KA) injection. In P2X7R knockout (KO) mice, prolonged astroglial HSP25 induction exerts 5′ adenosine monophosphate-activated protein kinase/unc-51 like autophagy activating kinase 1-mediated autophagic pathway independent of mammalian target of rapamycin (mTOR) activity following KA injection. Sustained HSP25 expression also enhances AKT-serine (S) 473 phosphorylation leading to astroglial autophagy via glycogen synthase kinase-3β/bax interacting factor 1 signaling pathway. However, it is unanswered how P2X7R deletion induces AKT-S473 hyperphosphorylation during autophagic process in astrocytes. In the present study, we found that AKT-S473 phosphorylation was increased by enhancing activity of focal adhesion kinase (FAK), independent of mTOR complex (mTORC) 1 and 2 activities in isolated astrocytes of P2X7R knockout (KO) mice following KA injection. In addition, HSP25 overexpression in P2X7R KO mice acted as a chaperone of AKT, which retained AKT-S473 phosphorylation by inhibiting the pleckstrin homology domain and leucine-rich repeat protein phosphatase (PHLPP) 1- and 2-binding to AKT. Therefore, our findings suggest that P2X7R may be a fine-tuner of AKT-S473 activity during astroglial autophagy by regulating FAK phosphorylation and HSP25-mediated inhibition of PHLPP1/2-AKT binding following KA treatment.
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15
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated Mdm2 dephosphorylation increases seizure susceptibility via abrogating PSD95 ubiquitination. Exp Neurol 2020; 331:113383. [DOI: 10.1016/j.expneurol.2020.113383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 01/29/2023]
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16
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Chen X, Bao G, Liu F. Inhibition of USP15 Prevent Glutamate-Induced Oxidative Damage by Activating Nrf2/HO-1 Signaling Pathway in HT22 Cells. Cell Mol Neurobiol 2020; 40:999-1010. [PMID: 31933062 DOI: 10.1007/s10571-020-00789-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/07/2020] [Indexed: 02/07/2023]
Abstract
Oxidative stress has been identified as the significant mediator in epilepsy, which is a chronic disorder in central nervous system. About 30% of epilepsy patients are refractory to antiepileptic drug treatment. However, the underlying mechanism of oxidative damage in epilepsy needs further investigation. In our study, we first find that ubiquitin-specific peptidase 15 (USP15) expression was upregulated in a pentylenetetrazole (PTZ) kindled rat model of epilepsy. Silencing USP15 protected against glutamate-mediated neuronal cell death, and inhibited the high expression levels of cleaved caspase-3. Knockout of USP15 significantly reduced intracellular reactive oxygen species (ROS) levels and enhanced superoxide dismutase (SOD) activity in HT22 cells under the exposure to glutamate treatment. Furthermore, USP15 inhibition induced nuclear factor erythroid-derived 2-related factor2 (Nrf2) nuclear translocation and promoted protein expression level of heme oxygenase (HO-1). Taken together, our findings first reveal a role of USP15 in the pathogenesis of epilepsy, and silencing USP15 in vitro protects against glutamate-mediated cytotoxicity in HT22 cells. Pharmacological inhibition of USP15 may alleviate epileptic seizures via fighting against oxidative damage, providing a novel antiepileptic target.
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Affiliation(s)
- Xiaojie Chen
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 201999, China
| | - Guanshui Bao
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 201999, China.
| | - Fangfang Liu
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 201999, China
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17
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Zhu J, Tsai NP. Ubiquitination and E3 Ubiquitin Ligases in Rare Neurological Diseases with Comorbid Epilepsy. Neuroscience 2020; 428:90-99. [DOI: 10.1016/j.neuroscience.2019.12.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022]
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