1
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Kim S, Jang G, Kim H, Lim D, Han KA, Um JW, Ko J. MDGAs perform activity-dependent synapse type-specific suppression via distinct extracellular mechanisms. Proc Natl Acad Sci U S A 2024; 121:e2322978121. [PMID: 38900791 PMCID: PMC11214077 DOI: 10.1073/pnas.2322978121] [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: 12/29/2023] [Accepted: 05/15/2024] [Indexed: 06/22/2024] Open
Abstract
MDGA (MAM domain containing glycosylphosphatidylinositol anchor) family proteins were previously identified as synaptic suppressive factors. However, various genetic manipulations have yielded often irreconcilable results, precluding precise evaluation of MDGA functions. Here, we found that, in cultured hippocampal neurons, conditional deletion of MDGA1 and MDGA2 causes specific alterations in synapse numbers, basal synaptic transmission, and synaptic strength at GABAergic and glutamatergic synapses, respectively. Moreover, MDGA2 deletion enhanced both N-methyl-D-aspartate (NMDA) receptor- and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated postsynaptic responses. Strikingly, ablation of both MDGA1 and MDGA2 abolished the effect of deleting individual MDGAs that is abrogated by chronic blockade of synaptic activity. Molecular replacement experiments further showed that MDGA1 requires the meprin/A5 protein/PTPmu (MAM) domain, whereas MDGA2 acts via neuroligin-dependent and/or MAM domain-dependent pathways to regulate distinct postsynaptic properties. Together, our data demonstrate that MDGA paralogs act as unique negative regulators of activity-dependent postsynaptic organization at distinct synapse types, and cooperatively contribute to adjustment of excitation-inhibition balance.
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Affiliation(s)
- Seungjoon Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Gyubin Jang
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Hyeonho Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Dongseok Lim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Kyung Ah Han
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Ji Won Um
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
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2
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Wang X, Lin D, Jiang J, Liu Y, Dong X, Fan J, Gong L, Shen W, Zeng L, Xu T, Jiang K, Connor SA, Xie Y. MDGA2 Constrains Glutamatergic Inputs Selectively onto CA1 Pyramidal Neurons to Optimize Neural Circuits for Plasticity, Memory, and Social Behavior. Neurosci Bull 2024:10.1007/s12264-023-01171-1. [PMID: 38321347 DOI: 10.1007/s12264-023-01171-1] [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: 06/30/2023] [Accepted: 10/08/2023] [Indexed: 02/08/2024] Open
Abstract
Synapse organizers are essential for the development, transmission, and plasticity of synapses. Acting as rare synapse suppressors, the MAM domain containing glycosylphosphatidylinositol anchor (MDGA) proteins contributes to synapse organization by inhibiting the formation of the synaptogenic neuroligin-neurexin complex. A previous analysis of MDGA2 mice lacking a single copy of Mdga2 revealed upregulated glutamatergic synapses and behaviors consistent with autism. However, MDGA2 is expressed in diverse cell types and is localized to both excitatory and inhibitory synapses. Differentiating the network versus cell-specific effects of MDGA2 loss-of-function requires a cell-type and brain region-selective strategy. To address this, we generated mice harboring a conditional knockout of Mdga2 restricted to CA1 pyramidal neurons. Here we report that MDGA2 suppresses the density and function of excitatory synapses selectively on pyramidal neurons in the mature hippocampus. Conditional deletion of Mdga2 in CA1 pyramidal neurons of adult mice upregulated miniature and spontaneous excitatory postsynaptic potentials, vesicular glutamate transporter 1 intensity, and neuronal excitability. These effects were limited to glutamatergic synapses as no changes were detected in miniature and spontaneous inhibitory postsynaptic potential properties or vesicular GABA transporter intensity. Functionally, evoked basal synaptic transmission and AMPAR receptor currents were enhanced at glutamatergic inputs. At a behavioral level, memory appeared to be compromised in Mdga2 cKO mice as both novel object recognition and contextual fear conditioning performance were impaired, consistent with deficits in long-term potentiation in the CA3-CA1 pathway. Social affiliation, a behavioral analog of social deficits in autism, was similarly compromised. These results demonstrate that MDGA2 confines the properties of excitatory synapses to CA1 neurons in mature hippocampal circuits, thereby optimizing this network for plasticity, cognition, and social behaviors.
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Affiliation(s)
- Xuehui Wang
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Donghui Lin
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Jie Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Yuhua Liu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Xinyan Dong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Jianchen Fan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Lifen Gong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Weida Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Linghui Zeng
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Tonghui Xu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Kewen Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China.
| | - Steven A Connor
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
| | - Yicheng Xie
- School of Life Sciences, Nanchang University, Nanchang, 330031, China.
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China.
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3
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Li HL, Guo RJ, Ai ZR, Han S, Guan Y, Li JF, Wang Y. Upregulation of Spinal MDGA1 in Rats After Nerve Injury Alters Interactions Between Neuroligin-2 and Postsynaptic Scaffolding Proteins and Increases GluR1 Subunit Surface Delivery in the Spinal Cord Dorsal Horn. Neurochem Res 2024; 49:507-518. [PMID: 37955815 DOI: 10.1007/s11064-023-04049-w] [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: 08/20/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/14/2023]
Abstract
Previous studies suggested that postsynaptic neuroligin-2 may shift from inhibitory toward excitatory function under pathological pain conditions. We hypothesize that nerve injury may increase the expression of spinal MAM-domain GPI-anchored molecule 1 (MDGA1), which can bind to neuroligin-2 and thereby, alter its interactions with postsynaptic scaffolding proteins and increase spinal excitatory synaptic transmission, leading to neuropathic pain. Western blot, immunofluorescence staining, and co-immunoprecipitation studies were conducted to examine the critical role of MDGA1 in the lumbar spinal cord dorsal horn in rats after spinal nerve ligation (SNL). Small interfering ribonucleic acids (siRNAs) targeting MDGA1 were used to examine the functional roles of MDGA1 in neuropathic pain. Protein levels of MDGA1 in the ipsilateral dorsal horn were significantly upregulated at day 7 post-SNL, as compared to that in naïve or sham rats. The increased levels of GluR1 in the synaptosomal membrane fraction of the ipsilateral dorsal horn tissues at day 7 post-SNL was normalized to near sham level by pretreatment with intrathecal MDGA1 siRNA2308, but not scrambled siRNA or vehicle. Notably, knocking down MDGA1 with siRNAs reduced the mechanical and thermal pain hypersensitivities, and inhibited the increased excitatory synaptic interaction between neuroligin-2 with PSD-95, and prevented the decreased inhibitory postsynaptic interactions between neuroligin-2 and Gephyrin. Our findings suggest that SNL upregulated MDGA1 expression in the dorsal horn, which contributes to the pain hypersensitivity through increasing the net excitatory interaction mediated by neuroligin-2 and surface delivery of GluR1 subunit in dorsal horn neurons.
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Affiliation(s)
- Hui-Li Li
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, No. 95, Yongan Road, Xicheng District, Beijing, 100050, China
| | - Rui-Juan Guo
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, No. 95, Yongan Road, Xicheng District, Beijing, 100050, China
| | - Zhang-Ran Ai
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Song Han
- Department of Neurobiology, Capital Medical University, Beijing, 100069, China
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Jun-Fa Li
- Department of Neurobiology, Capital Medical University, Beijing, 100069, China
| | - Yun Wang
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, No. 95, Yongan Road, Xicheng District, Beijing, 100050, China.
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4
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Benner O, Cast TP, Minamide LS, Lenninger Z, Bamburg JR, Chanda S. Multiple N-linked glycosylation sites critically modulate the synaptic abundance of neuroligin isoforms. J Biol Chem 2023; 299:105361. [PMID: 37865312 PMCID: PMC10679506 DOI: 10.1016/j.jbc.2023.105361] [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: 09/05/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/23/2023] Open
Abstract
In recent years, elegant glycomic and glycoproteomic approaches have revealed an intricate glycosylation profile of mammalian brain with enormous spatial and temporal diversities. Nevertheless, at a cellular level, it is unclear how these post-translational modifications affect various proteins to influence crucial neuronal properties. Here, we have investigated the impact of N-linked glycosylation on neuroligins (NLGNs), a class of cell-adhesion molecules that play instructive roles in synapse organization. We found that endogenous NLGN proteins are differentially glycosylated across several regions of murine brain in a sex-independent but isoform-dependent manner. In both rodent primary neurons derived from brain sections and human neurons differentiated from stem cells, all NLGN variants were highly enriched with multiple N-glycan subtypes, which cumulatively ensured their efficient trafficking to the cell surface. Removal of these N-glycosylation residues only had a moderate effect on NLGNs' stability or expression levels but particularly enhanced their retention at the endoplasmic reticulum. As a result, the glycosylation-deficient NLGNs exhibited considerable impairments in their dendritic distribution and postsynaptic accumulation, which in turn, virtually eliminated their ability to recruit presynaptic terminals and significantly reduced NLGN overexpression-induced assemblies of both glutamatergic and GABAergic synapse structures. Therefore, our results highlight an essential mechanistic contribution of N-linked glycosylations in facilitating the appropriate secretory transport of a major synaptic cell-adhesion molecule and promoting its cellular function in neurons.
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Affiliation(s)
- Orion Benner
- Biochemistry & Molecular Biology, Colorado State University, Fort Collins, USA
| | - Thomas P Cast
- Biochemistry & Molecular Biology, Colorado State University, Fort Collins, USA
| | - Laurie S Minamide
- Biochemistry & Molecular Biology, Colorado State University, Fort Collins, USA
| | - Zephyr Lenninger
- Molecular, Cellular & Integrated Neurosciences, Colorado State University, Fort Collins, Colorado, USA
| | - James R Bamburg
- Biochemistry & Molecular Biology, Colorado State University, Fort Collins, USA; Molecular, Cellular & Integrated Neurosciences, Colorado State University, Fort Collins, Colorado, USA; Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Soham Chanda
- Biochemistry & Molecular Biology, Colorado State University, Fort Collins, USA; Molecular, Cellular & Integrated Neurosciences, Colorado State University, Fort Collins, Colorado, USA; Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA.
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5
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Connor SA, Siddiqui TJ. Synapse organizers as molecular codes for synaptic plasticity. Trends Neurosci 2023; 46:971-985. [PMID: 37652840 DOI: 10.1016/j.tins.2023.08.001] [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: 05/21/2023] [Revised: 07/13/2023] [Accepted: 08/03/2023] [Indexed: 09/02/2023]
Abstract
Synapse organizing proteins are multifaceted molecules that coordinate the complex processes of brain development and plasticity at the level of individual synapses. Their importance is demonstrated by the major brain disorders that emerge when their function is compromised. The mechanisms whereby the various families of organizers govern synapses are diverse, but converge on the structure, function, and plasticity of synapses. Therefore, synapse organizers regulate how synapses adapt to ongoing activity, a process central for determining the developmental trajectory of the brain and critical to all forms of cognition. Here, we explore how synapse organizers set the conditions for synaptic plasticity and the associated molecular events, which eventually link to behavioral features of neurodevelopmental and neuropsychiatric disorders. We also propose central questions on how synapse organizers influence network function through integrating nanoscale and circuit-level organization of the brain.
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Affiliation(s)
- Steven A Connor
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
| | - Tabrez J Siddiqui
- PrairieNeuro Research Centre, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, MB R3E 0Z3, Canada; Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; The Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Program in Biomedical Engineering, University of Manitoba, Winnipeg, MB, Canada.
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6
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Bemben MA, Sandoval M, Le AA, Won S, Chau VN, Lauterborn JC, Incontro S, Li KH, Burlingame AL, Roche KW, Gall CM, Nicoll RA, Diaz-Alonso J. Contrastsing synaptic roles of MDGA1 and MDGA2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.25.542333. [PMID: 37720016 PMCID: PMC10503827 DOI: 10.1101/2023.05.25.542333] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Neurodevelopmental disorders are frequently linked to mutations in synaptic organizing molecules. MAM domain containing glycosylphosphatidylinositol anchor 1 and 2 (MDGA1 and MDGA2) are a family of synaptic organizers suggested to play an unusual role as synaptic repressors, but studies offer conflicting evidence for their localization. Using epitope-tagged MDGA1 and MDGA2 knock-in mice, we found that native MDGAs are expressed throughout the brain, peaking early in postnatal development. Surprisingly, endogenous MDGA1 was enriched at excitatory, but not inhibitory, synapses. Both shRNA knockdown and CRISPR/Cas9 knockout of MDGA1 resulted in cell-autonomous, specific impairment of AMPA receptor-mediated synaptic transmission, without affecting GABAergic transmission. Conversely, MDGA2 knockdown/knockout selectively depressed NMDA receptor-mediated transmission but enhanced inhibitory transmission. Our results establish that MDGA2 acts as a synaptic repressor, but only at inhibitory synapses, whereas both MDGAs are required for excitatory transmission. This nonoverlapping division of labor between two highly conserved synaptic proteins is unprecedented.
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Affiliation(s)
- Michael A. Bemben
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Matthew Sandoval
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
| | - Aliza A. Le
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
| | - Sehoon Won
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Vivian N. Chau
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
| | - Julie C. Lauterborn
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
| | - Salvatore Incontro
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA 94158, USA
- Present address: Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR1072, INSERM, Aix-Marseille University, Marseille, 13015, France
| | - Kathy H. Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alma L. Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Katherine W. Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Christine M. Gall
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
| | - Roger A. Nicoll
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA 94158, USA
- Department of Physiology, University of California at San Francisco, San Francisco, CA, 94158, USA
| | - Javier Diaz-Alonso
- Department of Anatomy & Neurobiology, University of California at Irvine, CA, 92617, USA
- Center for the Neurobiology of Learning and Memory, University of California at Irvine, CA, USA
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7
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Zhou Q. Organizing the synaptic junctions. J Biol Chem 2023; 299:104716. [PMID: 37060998 PMCID: PMC10192912 DOI: 10.1016/j.jbc.2023.104716] [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] [Accepted: 04/11/2023] [Indexed: 04/17/2023] Open
Abstract
Synaptic adhesion molecules (SAMs) are essential for driving the formation, maturation, and plasticity of synaptic connections for neural networks. MAM domain-containing glycosylphosphatidylinositol anchors (MDGAs) are a type of SAM that regulates the formation of trans-synaptic bridges, which are critical for neurotransmission and synaptic differentiation. In a recent issue of the JBC, Lee et al. uncovered that MDGA1 can control protein-protein interactions and synaptic cleft activity by adopting different global 3D conformations. This novel molecular mechanism may be applicable to other SAMs that regulate protein-protein interactions and nanoscale organization in the synaptic cleft.
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Affiliation(s)
- Qiangjun Zhou
- Department of Cell and Developmental Biology, Vanderbilt Brain Institute, Center for Structural Biology, Vanderbilt Kennedy Center, Vanderbilt University, Nashville, Tennessee, USA.
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8
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Lee H, Chofflet N, Liu J, Fan S, Lu Z, Resua Rojas M, Penndorf P, Bailey AO, Russell WK, Machius M, Ren G, Takahashi H, Rudenko G. Designer molecules of the synaptic organizer MDGA1 reveal 3D conformational control of biological function. J Biol Chem 2023; 299:104586. [PMID: 36889589 PMCID: PMC10131064 DOI: 10.1016/j.jbc.2023.104586] [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: 01/10/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/08/2023] Open
Abstract
MDGAs (MAM domain-containing glycosylphosphatidylinositol anchors) are synaptic cell surface molecules that regulate the formation of trans-synaptic bridges between neurexins (NRXNs) and neuroligins (NLGNs), which promote synaptic development. Mutations in MDGAs are implicated in various neuropsychiatric diseases. MDGAs bind NLGNs in cis on the postsynaptic membrane and physically block NLGNs from binding to NRXNs. In crystal structures, the six immunoglobulin (Ig) and single fibronectin III domains of MDGA1 reveal a striking compact, triangular shape, both alone and in complex with NLGNs. Whether this unusual domain arrangement is required for biological function or other arrangements occur with different functional outcomes is unknown. Here, we show that WT MDGA1 can adopt both compact and extended 3D conformations that bind NLGN2. Designer mutants targeting strategic molecular elbows in MDGA1 alter the distribution of 3D conformations while leaving the binding affinity between soluble ectodomains of MDGA1 and NLGN2 intact. In contrast, in a cellular context, these mutants result in unique combinations of functional consequences, including altered binding to NLGN2, decreased capacity to conceal NLGN2 from NRXN1β, and/or suppressed NLGN2-mediated inhibitory presynaptic differentiation, despite the mutations being located far from the MDGA1-NLGN2 interaction site. Thus, the 3D conformation of the entire MDGA1 ectodomain appears critical for its function, and its NLGN-binding site on Ig1-Ig2 is not independent of the rest of the molecule. As a result, global 3D conformational changes to the MDGA1 ectodomain via strategic elbows may form a molecular mechanism to regulate MDGA1 action within the synaptic cleft.
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Affiliation(s)
- Hubert Lee
- Deptartment of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Nicolas Chofflet
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Quebec, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Shanghua Fan
- Deptartment of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Zhuoyang Lu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Martin Resua Rojas
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Quebec, Canada
| | - Patrick Penndorf
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Quebec, Canada
| | - Aaron O Bailey
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Mischa Machius
- Deptartment of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Quebec, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montréal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montréal, Quebec, Canada.
| | - Gabby Rudenko
- Deptartment of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA.
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9
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Li L, Ji J, Song F, Hu J. Intercellular Receptor-ligand Binding: Effect of Protein-membrane Interaction. J Mol Biol 2023; 435:167787. [PMID: 35952805 DOI: 10.1016/j.jmb.2022.167787] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/03/2022] [Accepted: 08/04/2022] [Indexed: 02/04/2023]
Abstract
Gaining insights into the intercellular receptor-ligand binding is of great importance for understanding numerous physiological and pathological processes, and stimulating new strategies in drug design and discovery. In contrast to the in vitro protein interaction in solution, the anchored receptor and ligand molecules interact with membrane in situ, which affects the intercellular receptor-ligand binding. Here, we review theoretical, simulation and experimental works regarding the regulatory effects of protein-membrane interactions on intercellular receptor-ligand binding mainly from the following aspects: membrane fluctuations, membrane curvature, glycocalyx, and lipid raft. In addition, we discuss biomedical significances and possible research directions to advance the field and highlight the importance of understanding of coupling effects of these factors in pharmaceutical development.
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Affiliation(s)
- Long Li
- Kuang Yaming Honors School and Institute for Brain Sciences, Nanjing University, 210023 Nanjing, China; State Key Laboratory of Nonlinear Mechanics and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, 100190 Beijing, China
| | - Jing Ji
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Fan Song
- State Key Laboratory of Nonlinear Mechanics and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, 100190 Beijing, China; School of Engineering Science, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jinglei Hu
- Kuang Yaming Honors School and Institute for Brain Sciences, Nanjing University, 210023 Nanjing, China.
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10
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Zheng S, Zou M, Shao Y, Wu H, Wu H, Wang X. Two-dimensional measurements of receptor-ligand interactions. Front Mol Biosci 2023; 10:1154074. [PMID: 36876050 PMCID: PMC9981951 DOI: 10.3389/fmolb.2023.1154074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/08/2023] [Indexed: 02/19/2023] Open
Abstract
Gaining insight into the two-dimensional receptor-ligand interactions, which play a significant role in various pivotal biological processes such as immune response and cancer metastasis, will deepen our understanding of numerous physiological and pathological mechanisms and contribute to biomedical applications and drug design. A central issue involved is how to measure the in situ receptor-ligand binding kinetics. Here, we review several representative mechanical-based and fluorescence-based methods, and briefly discuss the strengths and weaknesses for each method. In addition, we emphasize the great importance of the combination of experimental and computational methods in studying the receptor-ligand interactions, and further studies should focus on the synergistic development of experimental and computational methods.
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Affiliation(s)
- Songjie Zheng
- Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.,School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Min Zou
- Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.,School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Yingfeng Shao
- Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Huaping Wu
- College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Helong Wu
- College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Xiaohuan Wang
- Department of Rehabilitation Medicine, Peking University Third Hospital, Beijing, China
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11
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Li H, Guo R, Guan Y, Li J, Wang Y. Modulation of Trans-Synaptic Neurexin-Neuroligin Interaction in Pathological Pain. Cells 2022; 11:cells11121940. [PMID: 35741069 PMCID: PMC9222181 DOI: 10.3390/cells11121940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 11/16/2022] Open
Abstract
Synapses serve as the interface for the transmission of information between neurons in the central nervous system. The structural and functional characteristics of synapses are highly dynamic, exhibiting extensive plasticity that is shaped by neural activity and regulated primarily by trans-synaptic cell-adhesion molecules (CAMs). Prototypical trans-synaptic CAMs, such as neurexins (Nrxs) and neuroligins (Nlgs), directly regulate the assembly of presynaptic and postsynaptic molecules, including synaptic vesicles, active zone proteins, and receptors. Therefore, the trans-synaptic adhesion mechanisms mediated by Nrx-Nlg interaction can contribute to a range of synaptopathies in the context of pathological pain and other neurological disorders. The present review provides an overview of the current understanding of the roles of Nrx-Nlg interaction in the regulation of trans-synaptic connections, with a specific focus on Nrx and Nlg structures, the dynamic shaping of synaptic function, and the dysregulation of Nrx-Nlg in pathological pain. Additionally, we discuss a range of proteins capable of modulating Nrx-Nlg interactions at the synaptic cleft, with the objective of providing a foundation to guide the future development of novel therapeutic agents for managing pathological pain.
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Affiliation(s)
- Huili Li
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China;
| | - Ruijuan Guo
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100030, China;
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
| | - Junfa Li
- Department of Neurobiology, Capital Medical University, Beijing 100069, China;
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China;
- Correspondence: ; Tel.: +86-10-85231463
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12
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Toledo A, Letellier M, Bimbi G, Tessier B, Daburon S, Favereaux A, Chamma I, Vennekens K, Vanderlinden J, Sainlos M, de Wit J, Choquet D, Thoumine O. MDGAs are fast-diffusing molecules that delay excitatory synapse development by altering neuroligin behavior. eLife 2022; 11:75233. [PMID: 35532105 PMCID: PMC9084894 DOI: 10.7554/elife.75233] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 04/11/2022] [Indexed: 12/28/2022] Open
Abstract
MDGA molecules can bind neuroligins and interfere with trans-synaptic interactions to neurexins, thereby impairing synapse development. However, the subcellular localization and dynamics of MDGAs, or their specific action mode in neurons remain unclear. Here, surface immunostaining of endogenous MDGAs and single molecule tracking of recombinant MDGAs in dissociated hippocampal neurons reveal that MDGAs are homogeneously distributed and exhibit fast membrane diffusion, with a small reduction in mobility across neuronal maturation. Knocking-down/out MDGAs using shRNAs and CRISPR/Cas9 strategies increases the density of excitatory synapses, the membrane confinement of neuroligin-1, and the phosphotyrosine level of neuroligins associated with excitatory post-synaptic differentiation. Finally, MDGA silencing reduces the mobility of AMPA receptors, increases the frequency of miniature EPSCs (but not IPSCs), and selectively enhances evoked AMPA-receptor-mediated EPSCs in CA1 pyramidal neurons. Overall, our results support a mechanism by which interactions between MDGAs and neuroligin-1 delays the assembly of functional excitatory synapses containing AMPA receptors.
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Affiliation(s)
- Andrea Toledo
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Mathieu Letellier
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Giorgia Bimbi
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Béatrice Tessier
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Sophie Daburon
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Alexandre Favereaux
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Ingrid Chamma
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Kristel Vennekens
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Jeroen Vanderlinden
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Matthieu Sainlos
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Joris de Wit
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Daniel Choquet
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
- University of Bordeaux, CNRS UAR 3420, INSERM, Bordeaux Imaging Center
| | - Olivier Thoumine
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
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13
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Kim J, Roh JD, Kim S, Kang H, Bae M, Kim E. Slc6a20a Heterozygous and Homozygous Mutant Mice Display Differential Behavioral and Transcriptomic Changes. Front Mol Neurosci 2022; 15:857820. [PMID: 35321029 PMCID: PMC8936588 DOI: 10.3389/fnmol.2022.857820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/28/2022] [Indexed: 11/23/2022] Open
Abstract
SLC6A20A is a proline and glycine transporter known to regulate glycine homeostasis and NMDA receptor (NMDAR) function in the brain. A previous study found increases in ambient glycine levels and NMDA receptor-mediated synaptic transmission in the brains of Slc6a20a-haploinsufficient mice, but it remained unknown whether Slc6a20a deficiency leads to disease-related behavioral deficits in mice. Here, we report that Slc6a20a heterozygous and homozygous mutant mice display differential behavioral phenotypes in locomotor, repetitive behavioral, and spatial and fear memory domains. In addition, these mice show differential transcriptomic changes in synapse, ribosome, mitochondria, autism, epilepsy, and neuron-related genes. These results suggest that heterozygous and homozygous Slc6a20a deletions in mice lead to differential changes in behaviors and transcriptomes.
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Affiliation(s)
- Junhyung Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea
| | - Junyeop Daniel Roh
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Seongbin Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea
| | - Hyojin Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information (KISTI), Daejeon, South Korea
| | - Mihyun Bae
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
- *Correspondence: Eunjoon Kim,
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14
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Kim J, Kim S, Kim H, Hwang IW, Bae S, Karki S, Kim D, Ogelman R, Bang G, Kim JY, Kajander T, Um JW, Oh WC, Ko J. MDGA1 negatively regulates amyloid precursor protein-mediated synapse inhibition in the hippocampus. Proc Natl Acad Sci U S A 2022; 119:e2115326119. [PMID: 35074912 PMCID: PMC8795569 DOI: 10.1073/pnas.2115326119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/05/2021] [Indexed: 12/20/2022] Open
Abstract
Balanced synaptic inhibition, controlled by multiple synaptic adhesion proteins, is critical for proper brain function. MDGA1 (meprin, A-5 protein, and receptor protein-tyrosine phosphatase mu [MAM] domain-containing glycosylphosphatidylinositol anchor protein 1) suppresses synaptic inhibition in mammalian neurons, yet the molecular mechanisms underlying MDGA1-mediated negative regulation of GABAergic synapses remain unresolved. Here, we show that the MDGA1 MAM domain directly interacts with the extension domain of amyloid precursor protein (APP). Strikingly, MDGA1-mediated synaptic disinhibition requires the MDGA1 MAM domain and is prominent at distal dendrites of hippocampal CA1 pyramidal neurons. Down-regulation of APP in presynaptic GABAergic interneurons specifically suppressed GABAergic, but not glutamatergic, synaptic transmission strength and inputs onto both the somatic and dendritic compartments of hippocampal CA1 pyramidal neurons. Moreover, APP deletion manifested differential effects in somatostatin- and parvalbumin-positive interneurons in the hippocampal CA1, resulting in distinct alterations in inhibitory synapse numbers, transmission, and excitability. The infusion of MDGA1 MAM protein mimicked postsynaptic MDGA1 gain-of-function phenotypes that involve the presence of presynaptic APP. The overexpression of MDGA1 wild type or MAM, but not MAM-deleted MDGA1, in the hippocampal CA1 impaired novel object-recognition memory in mice. Thus, our results establish unique roles of APP-MDGA1 complexes in hippocampal neural circuits, providing unprecedented insight into trans-synaptic mechanisms underlying differential tuning of neuronal compartment-specific synaptic inhibition.
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Affiliation(s)
- Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Seungjoon Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - In-Wook Hwang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Sungwon Bae
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Sudeep Karki
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Roberto Ogelman
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Geul Bang
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang 305-732, Korea
| | - Jin Young Kim
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang 305-732, Korea
| | - Tommi Kajander
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Won Chan Oh
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045;
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea;
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15
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Zhang Z, Hou M, Ou H, Wang D, Li Z, Zhang H, Lu J. Expression and structural analysis of human neuroligin 2 and neuroligin 3 implicated in autism spectrum disorders. Front Endocrinol (Lausanne) 2022; 13:1067529. [PMID: 36479216 PMCID: PMC9719943 DOI: 10.3389/fendo.2022.1067529] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 10/31/2022] [Indexed: 11/22/2022] Open
Abstract
The development of autism spectrum disorders (ASDs) involves both environmental factors such as maternal diabetes and genetic factors such as neuroligins (NLGNs). NLGN2 and NLGN3 are two members of NLGNs with distinct distributions and functions in synapse development and plasticity. The relationship between maternal diabetes and NLGNs, and the distinct working mechanisms of different NLGNs currently remain unclear. Here, we first analyzed the expression levels of NLGN2 and NLGN3 in a streptozotocin-induced ASD mouse model and different brain regions to reveal their differences and similarities. Then, cryogenic electron microscopy (cryo-EM) structures of human NLGN2 and NLGN3 were determined. The overall structures are similar to their homologs in previous reports. However, structural comparisons revealed the relative rotations of two protomers in the homodimers of NLGN2 and NLGN3. Taken together with the previously reported NLGN2-MDGA1 complex, we speculate that the distinct assembly adopted by NLGN2 and NLGN3 may affect their interactions with MDGAs. Our results provide structural insights into the potential distinct mechanisms of NLGN2 and NLGN3 implicated in the development of ASD.
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Affiliation(s)
- Zhenzhen Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Mengzhuo Hou
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Huaxing Ou
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Daping Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Department of Orthopedics, Shenzhen Intelligent Orthopaedics and Biomedical Innovation Platform, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Zhifang Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Jianping Lu, ; Huawei Zhang, ; Zhifang Li,
| | - Huawei Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Jianping Lu, ; Huawei Zhang, ; Zhifang Li,
| | - Jianping Lu
- Department of Child and Adolescent Psychiatry, Shenzhen Kangning Hospital, Shenzhen Mental Health Center, Shenzhen, China
- *Correspondence: Jianping Lu, ; Huawei Zhang, ; Zhifang Li,
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16
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Lie E, Yeo Y, Lee EJ, Shin W, Kim K, Han KA, Yang E, Choi TY, Bae M, Lee S, Um SM, Choi SY, Kim H, Ko J, Kim E. SALM4 negatively regulates NMDA receptor function and fear memory consolidation. Commun Biol 2021; 4:1138. [PMID: 34588597 PMCID: PMC8481232 DOI: 10.1038/s42003-021-02656-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 09/09/2021] [Indexed: 02/08/2023] Open
Abstract
Many synaptic adhesion molecules positively regulate synapse development and function, but relatively little is known about negative regulation. SALM4/Lrfn3 (synaptic adhesion-like molecule 4/leucine rich repeat and fibronectin type III domain containing 3) inhibits synapse development by suppressing other SALM family proteins, but whether SALM4 also inhibits synaptic function and specific behaviors remains unclear. Here we show that SALM4-knockout (Lrfn3-/-) male mice display enhanced contextual fear memory consolidation (7-day post-training) but not acquisition or 1-day retention, and exhibit normal cued fear, spatial, and object-recognition memory. The Lrfn3-/- hippocampus show increased currents of GluN2B-containing N-methyl-D-aspartate (NMDA) receptors (GluN2B-NMDARs), but not α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors (AMPARs), which requires the presynaptic receptor tyrosine phosphatase PTPσ. Chronic treatment of Lrfn3-/- mice with fluoxetine, a selective serotonin reuptake inhibitor used to treat excessive fear memory that directly inhibits GluN2B-NMDARs, normalizes NMDAR function and contextual fear memory consolidation in Lrfn3-/- mice, although the GluN2B-specific NMDAR antagonist ifenprodil was not sufficient to reverse the enhanced fear memory consolidation. These results suggest that SALM4 suppresses excessive GluN2B-NMDAR (not AMPAR) function and fear memory consolidation (not acquisition).
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Affiliation(s)
- Eunkyung Lie
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea ,grid.255168.d0000 0001 0671 5021Department of Chemistry, Dongguk University, Seoul, 04620 Korea
| | - Yeji Yeo
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141 Korea
| | - Eun-Jae Lee
- grid.267370.70000 0004 0533 4667Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, 05505 Korea
| | - Wangyong Shin
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Kyungdeok Kim
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Kyung Ah Han
- grid.417736.00000 0004 0438 6721Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988 Korea
| | - Esther Yang
- grid.222754.40000 0001 0840 2678Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, 02841 Korea
| | - Tae-Yong Choi
- grid.31501.360000 0004 0470 5905Department of Physiology and Neuroscience, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080 Korea
| | - Mihyun Bae
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Suho Lee
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Seung Min Um
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141 Korea
| | - Se-Young Choi
- grid.31501.360000 0004 0470 5905Department of Physiology and Neuroscience, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080 Korea
| | - Hyun Kim
- grid.222754.40000 0001 0840 2678Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, 02841 Korea
| | - Jaewon Ko
- grid.417736.00000 0004 0438 6721Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988 Korea
| | - Eunjoon Kim
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea ,grid.267370.70000 0004 0533 4667Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, 05505 Korea
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17
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Xiao Y, Wang X, Wang S, Li J, Xu X, Wang M, Li G, Shen W. Celastrol Attenuates Learning and Memory Deficits in an Alzheimer's Disease Rat Model. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5574207. [PMID: 34350293 PMCID: PMC8328733 DOI: 10.1155/2021/5574207] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/19/2021] [Accepted: 07/08/2021] [Indexed: 01/31/2023]
Abstract
Alzheimer's disease (AD) is a chronic progressive neurodegenerative disorder that is associated with learning, memory, and cognitive deficits. Neuroinflammation and synapse loss are involved in the pathology of AD. Diverse measures have been applied to treat AD, but currently, there is no effective treatment. Celastrol (CEL) is a pentacyclic triterpene isolated from Tripterygium wilfordii Hook F that has been shown to enhance cell viability and inhibit amyloid-β production induced by lipopolysaccharides in vitro. In the present study, the protective effect of CEL on Aβ 25-35-induced rat model of AD was assessed. Our results showed that CEL administration at a dose of 2 mg/kg/day improved spatial memory in the Morris water maze. Further biochemical analysis showed that CEL treatment of intrahippocampal Aβ 25-35-microinjected rats attenuated hippocampal NF-κB activity; inhibited proinflammatory markers, namely, IL-1β, IL-6, and TNF-α; and upregulated anti-inflammatory factors, such as IL-4 and IL-10. Furthermore, CEL upregulated hippocampal neurexin-1β, neuroligin-1, CA1, and PSD95 expression levels, which may improve synaptic function. Simultaneously, CEL also increased glucose metabolism in Aβ 25-35-microinjected rats. In conclusion, CEL could exert protective effects against learning and memory decline induced by intrahippocampal Aβ 25-35 through anti-inflammation, promote synaptic development, and maintain hippocampal energy metabolism.
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Affiliation(s)
- Yao Xiao
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xifeng Wang
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Siyi Wang
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Li
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xueyu Xu
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Min Wang
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Li
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Shen
- Department of Neurology, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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18
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Steffen DM, Ferri SL, Marcucci CG, Blocklinger KL, Molumby MJ, Abel T, Weiner JA. The γ-Protocadherins Interact Physically and Functionally with Neuroligin-2 to Negatively Regulate Inhibitory Synapse Density and Are Required for Normal Social Interaction. Mol Neurobiol 2021; 58:2574-2589. [PMID: 33471287 PMCID: PMC8137559 DOI: 10.1007/s12035-020-02263-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 12/15/2020] [Indexed: 12/16/2022]
Abstract
Cell adhesion molecules (CAMs) are key players in the formation of neural circuits during development. The γ-protocadherins (γ-Pcdhs), a family of 22 CAMs encoded by the Pcdhg gene cluster, are known to play important roles in dendrite arborization, axon targeting, and synapse development. We showed previously that multiple γ-Pcdhs interact physically with the autism-associated CAM neuroligin-1, and inhibit the latter's ability to promote excitatory synapse maturation. Here, we show that γ-Pcdhs can also interact physically with the related neuroligin-2, and inhibit this CAM's ability to promote inhibitory synapse development. In an artificial synapse assay, γ-Pcdhs co-expressed with neuroligin-2 in non-neuronal cells reduce inhibitory presynaptic maturation in contacting hippocampal axons. Mice lacking the γ-Pcdhs from the forebrain (including the cortex, the hippocampus, and portions of the amygdala) exhibit increased inhibitory synapse density and increased co-localization of neuroligin-2 with inhibitory postsynaptic markers in vivo. These Pcdhg mutants also exhibit defective social affiliation and an anxiety-like phenotype in behavioral assays. Together, these results suggest that γ-Pcdhs negatively regulate neuroligins to limit synapse density in a manner that is important for normal behavior.
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Affiliation(s)
- David M Steffen
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Biology, The University of Iowa, Iowa City, IA, 52242, USA
| | - Sarah L Ferri
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Neuroscience and Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA, 52242, USA
| | - Charles G Marcucci
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Biology, The University of Iowa, Iowa City, IA, 52242, USA
| | - Kelsey L Blocklinger
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Neuroscience and Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA, 52242, USA
| | - Michael J Molumby
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Biology, The University of Iowa, Iowa City, IA, 52242, USA
| | - Ted Abel
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Neuroscience and Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA, 52242, USA
| | - Joshua A Weiner
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, 52242, USA.
- Department of Biology, The University of Iowa, Iowa City, IA, 52242, USA.
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19
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Xue K, Hu Y, Gu S, Wang C, Kong R, Xie W, Li J. Using structural analysis to clarify the impact of single nucleotide variants in neurexin/neuroligin revealed in clinical genomic sequencing. J Biomol Struct Dyn 2021; 40:8085-8099. [PMID: 33818307 DOI: 10.1080/07391102.2021.1907225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The synapse is a highly specialized and dynamic structure, which is involved in regulating neurotransmission. Nerve cell adhesion molecule is a kind of transmembrane protein that mediates the interaction between cells and cells, cells and extracellular matrix, and plays a role in cell recognition, metastasis, and transmembrane signal transduction. Among nerve cell adhesion molecules, Neurexins (NRXNs) and Neuroligins (NLGNs) have been focused due to the relation with autism and other neuropsychiatric diseases. The previous research discovered numerous variants in NRXNs and NLGNs reported in neurodevelopmental disorders by genomic sequencing. However, structural variants in synaptic molecules caused by genome variants still prevent us from understanding the molecular mechanism of diseases. Thus, we sought to conduct a comprehensive risk assessment of the known NRXN and NLGN gene variants by protein structure analysis. In this study, we analyzed the structural properties of the NRXN/NLGN complex by calculating free energy in residue scanning, in combination with existing risk evaluation tools to focus on candidate missense mutations. Our calculations show that five candidate missense mutations in NLGNs can reduce the stability of NLGNs and even prevent the formation of NRXN/NLGN complexes, namely R87W, R204H, R437H, R437C and R583W. In addition, we found that the affinity of the amino acid substitution (Leu593Phe) (ΔΔG(affinity)) changes the affinity of the NLGN dimer. Overall, we have identified important potential pathological variants that provide clues to biomarkers.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kaiyu Xue
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Yunyun Hu
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Shuanglin Gu
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Chao Wang
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Ren Kong
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou, China
| | - Wei Xie
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Jian Li
- Key Laboratory of DGHD, MOE, Institute of Life Sciences, Southeast University, Nanjing, China
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20
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Interplay between hevin, SPARC, and MDGAs: Modulators of neurexin-neuroligin transsynaptic bridges. Structure 2021; 29:664-678.e6. [PMID: 33535026 DOI: 10.1016/j.str.2021.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/20/2020] [Accepted: 01/08/2021] [Indexed: 12/18/2022]
Abstract
Hevin is secreted by astrocytes and its synaptogenic effects are antagonized by the related protein, SPARC. Hevin stabilizes neurexin-neuroligin transsynaptic bridges in vivo. A third protein, membrane-tethered MDGA, blocks these bridges. Here, we reveal the molecular underpinnings of a regulatory network formed by this trio of proteins. The hevin FS-EC structure differs from SPARC, in that the EC domain appears rearranged around a conserved core. The FS domain is structurally conserved and it houses nanomolar affinity binding sites for neurexin and neuroligin. SPARC also binds neurexin and neuroligin, competing with hevin, so its antagonist action is rooted in its shortened N-terminal region. Strikingly, the hevin FS domain competes with MDGA for an overlapping binding site on neuroligin, while the hevin EC domain binds the extracellular matrix protein collagen (like SPARC), so that this trio of proteins can regulate neurexin-neuroligin transsynaptic bridges and also extracellular matrix interactions, impacting synapse formation and ultimately neural circuits.
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21
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Kim HY, Um JW, Ko J. Proper synaptic adhesion signaling in the control of neural circuit architecture and brain function. Prog Neurobiol 2021; 200:101983. [PMID: 33422662 DOI: 10.1016/j.pneurobio.2020.101983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Trans-synaptic cell-adhesion molecules are critical for governing various stages of synapse development and specifying neural circuit properties via the formation of multifarious signaling pathways. Recent studies have pinpointed the putative roles of trans-synaptic cell-adhesion molecules in mediating various cognitive functions. Here, we review the literature on the roles of a diverse group of central synaptic organizers, including neurexins (Nrxns), leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs), and their associated binding proteins, in regulating properties of specific type of synapses and neural circuits. In addition, we highlight the findings that aberrant synaptic adhesion signaling leads to alterations in the structures, transmission, and plasticity of specific synapses across diverse brain areas. These results seem to suggest that proper trans-synaptic signaling pathways by Nrxns, LAR-RPTPs, and their interacting network is likely to constitute central molecular complexes that form the basis for cognitive functions, and that these complexes are heterogeneously and complexly disrupted in many neuropsychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Hee Young Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea; Core Protein Resources Center, DGIST, Daegu, 42988, South Korea.
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea.
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22
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Comoletti D, Trobiani L, Chatonnet A, Bourne Y, Marchot P. Comparative mapping of selected structural determinants on the extracellular domains of cholinesterase-like cell-adhesion molecules. Neuropharmacology 2020; 184:108381. [PMID: 33166544 DOI: 10.1016/j.neuropharm.2020.108381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/10/2020] [Accepted: 10/29/2020] [Indexed: 11/18/2022]
Abstract
Cell adhesion generally involves formation of homophilic or heterophilic protein complexes between two cells to form transcellular junctions. Neural cell-adhesion members of the α/β-hydrolase fold superfamily of proteins use their extracellular or soluble cholinesterase-like domain to bind cognate partners across cell membranes, as illustrated by the neuroligins. These cell-adhesion molecules currently comprise the synaptic organizers neuroligins found in all animal phyla, along with three proteins found only in invertebrates: the guidance molecule neurotactin, the glia-specific gliotactin, and the basement membrane protein glutactin. Although these proteins share a cholinesterase-like fold, they lack one or more residues composing the catalytic triad responsible for the enzymatic activity of the cholinesterases. Conversely, they are found in various subcellular localisations and display specific disulfide bonding and N-glycosylation patterns, along with individual surface determinants possibly associated with recognition and binding of protein partners. Formation of non-covalent dimers typical of the cholinesterases is documented for mammalian neuroligins, yet whether invertebrate neuroligins and their neurotactin, gliotactin and glutactin relatives also form dimers in physiological conditions is unknown. Here we provide a brief overview of the localization, function, evolution, and conserved versus individual structural determinants of these cholinesterase-like cell-adhesion proteins. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.
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Affiliation(s)
- Davide Comoletti
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand; Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Laura Trobiani
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Arnaud Chatonnet
- Lab 'Dynamique Musculaire et Métabolisme', Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE) / Université Montpellier, Montpellier, France
| | - Yves Bourne
- Lab 'Architecture et Fonction des Macromolécules Biologiques (AFMB)', Centre National de la Recherche Scientifique (CNRS)/Aix-Marseille Univ, Faculté des Sciences - Campus Luminy, Marseille, France
| | - Pascale Marchot
- Lab 'Architecture et Fonction des Macromolécules Biologiques (AFMB)', Centre National de la Recherche Scientifique (CNRS)/Aix-Marseille Univ, Faculté des Sciences - Campus Luminy, Marseille, France.
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23
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The soluble neurexin-1β ectodomain causes calcium influx and augments dendritic outgrowth and synaptic transmission. Sci Rep 2020; 10:18041. [PMID: 33093500 PMCID: PMC7582164 DOI: 10.1038/s41598-020-75047-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/08/2020] [Indexed: 12/15/2022] Open
Abstract
Classically, neurexins are thought to mediate synaptic connections through trans interactions with a number of different postsynaptic partners. Neurexins are cleaved by metalloproteases in an activity-dependent manner, releasing the soluble extracellular domain. Here, we report that in both immature (before synaptogenesis) and mature (after synaptogenesis) hippocampal neurons, the soluble neurexin-1β ectodomain triggers acute Ca2+-influx at the dendritic/postsynaptic side. In both cases, neuroligin-1 expression was required. In immature neurons, calcium influx required N-type calcium channels and stimulated dendritic outgrowth and neuronal survival. In mature glutamatergic neurons the neurexin-1β ectodomain stimulated calcium influx through NMDA-receptors, which increased presynaptic release probability. In contrast, prolonged exposure to the ectodomain led to inhibition of synaptic transmission. This secondary inhibition was activity- and neuroligin-1 dependent and caused by a reduction in the readily-releasable pool of vesicles. A synthetic peptide modeled after the neurexin-1β:neuroligin-1 interaction site reproduced the cellular effects of the neurexin-1β ectodomain. Collectively, our findings demonstrate that the soluble neurexin ectodomain stimulates growth of neurons and exerts acute and chronic effects on trans-synaptic signaling involved in setting synaptic strength.
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24
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Mares-Mejía I, García-Ramírez B, Torres-Larios A, Rodríguez-Hernández A, Osornio-Hernández AI, Terán-Olvera G, Ortega E, Rodríguez-Romero A. Novel murine mAbs define specific and cross-reactive epitopes on the latex profilin panallergen Hev b 8. Mol Immunol 2020; 128:10-21. [PMID: 33045539 DOI: 10.1016/j.molimm.2020.09.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 09/10/2020] [Accepted: 09/25/2020] [Indexed: 01/06/2023]
Abstract
The production of specific antibodies able to recognize allergens from different sources or block interactions between allergens and antibodies mediating allergic reactions is crucial for developing successful tools for diagnostics and therapeutics. Panallergens are highly conserved proteins present in widely different species, implicated in relevant cross-reactions. The panallergen latex profilin (Hev b 8) has been associated with the latex-food-pollen syndrome. We generated five monoclonal IgGs and one IgE from murine hybridomas against recombinant Hev b 8 and evaluated their interaction with this allergen using ELISA and biolayer interferometry (BLI). Affinity purified mAbs exhibited high binding affinities towards rHev b 8, with KD1 values ranging from 10-10 M to 10-11 M. Some of these antibodies also recognized the recombinant profilins from maize and tomato (Zea m 12 and Sola l 1), and the ash tree pollen (Fra e 2). Competition ELISA demonstrated that some mAb pairs could bind simultaneously to rHev b 8. Using BLI, we detected competitive, non-competitive, and partial-competition interactions between pairs of mAbs with rHev b 8, suggesting the existence of at least two non-overlapping epitopes on the surface of this allergen. Three-dimensional models of the Fv of 1B4 and 2D10 IgGs and docking simulations of these Fvs with rHev b 8 revealed these epitopes. Furthermore, these two mAbs inhibited the interaction of polyclonal IgE and IgG4 antibodies from profilin-allergic patients with rHev b 8, indicating that the mAbs and the antibodies present in sera from allergic patients bind to overlapping epitopes on the allergen. These mAbs can be useful tools for immune-localization studies, immunoassay development, or standardization of allergenic products.
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Affiliation(s)
- Israel Mares-Mejía
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Benjamín García-Ramírez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Alfredo Torres-Larios
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Annia Rodríguez-Hernández
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Ana Isabel Osornio-Hernández
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Gabriela Terán-Olvera
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
| | - Enrique Ortega
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico.
| | - Adela Rodríguez-Romero
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, Coyoacán, Ciudad de México, 04510, Mexico.
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25
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Trobiani L, Meringolo M, Diamanti T, Bourne Y, Marchot P, Martella G, Dini L, Pisani A, De Jaco A, Bonsi P. The neuroligins and the synaptic pathway in Autism Spectrum Disorder. Neurosci Biobehav Rev 2020; 119:37-51. [PMID: 32991906 DOI: 10.1016/j.neubiorev.2020.09.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/11/2020] [Accepted: 09/19/2020] [Indexed: 12/13/2022]
Abstract
The genetics underlying autism spectrum disorder (ASD) is complex and heterogeneous, and de novo variants are found in genes converging in functional biological processes. Neuronal communication, including trans-synaptic signaling involving two families of cell-adhesion proteins, the presynaptic neurexins and the postsynaptic neuroligins, is one of the most recurrently affected pathways in ASD. Given the role of these proteins in determining synaptic function, abnormal synaptic plasticity and failure to establish proper synaptic contacts might represent mechanisms underlying risk of ASD. More than 30 mutations have been found in the neuroligin genes. Most of the resulting residue substitutions map in the extracellular, cholinesterase-like domain of the protein, and impair protein folding and trafficking. Conversely, the stalk and intracellular domains are less affected. Accordingly, several genetic animal models of ASD have been generated, showing behavioral and synaptic alterations. The aim of this review is to discuss the current knowledge on ASD-linked mutations in the neuroligin proteins and their effect on synaptic function, in various brain areas and circuits.
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Affiliation(s)
- Laura Trobiani
- Dept. Biology and Biotechnology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Maria Meringolo
- Lab. Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy; Dept. Systems Medicine, University Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Tamara Diamanti
- Dept. Biology and Biotechnology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Yves Bourne
- Lab. "Architecture et Fonction des Macromolécules Biologiques", CNRS/Aix Marseille Univ, Faculté des Sciences - Campus Luminy, 163 Avenue de Luminy, 13288 Marseille cedex 09, France
| | - Pascale Marchot
- Lab. "Architecture et Fonction des Macromolécules Biologiques", CNRS/Aix Marseille Univ, Faculté des Sciences - Campus Luminy, 163 Avenue de Luminy, 13288 Marseille cedex 09, France
| | - Giuseppina Martella
- Lab. Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy; Dept. Systems Medicine, University Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Luciana Dini
- Dept. Biology and Biotechnology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Antonio Pisani
- Lab. Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy; Dept. Systems Medicine, University Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Antonella De Jaco
- Dept. Biology and Biotechnology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
| | - Paola Bonsi
- Lab. Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143 Rome, Italy.
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26
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Platsaki S, Zhou X, Pinan-Lucarré B, Delauzun V, Tu H, Mansuelle P, Fourquet P, Bourne Y, Bessereau JL, Marchot P. The Ig-like domain of Punctin/MADD-4 is the primary determinant for interaction with the ectodomain of neuroligin NLG-1. J Biol Chem 2020; 295:16267-16279. [PMID: 32928959 DOI: 10.1074/jbc.ra120.014591] [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: 05/27/2020] [Revised: 09/02/2020] [Indexed: 02/01/2023] Open
Abstract
Punctin/MADD-4, a member of the ADAMTSL extracellular matrix protein family, was identified as an anterograde synaptic organizer in the nematode Caenorhabditis elegans. At GABAergic neuromuscular junctions, the short isoform MADD-4B binds the ectodomain of neuroligin NLG-1, itself a postsynaptic organizer of inhibitory synapses. To identify the molecular bases of their partnership, we generated recombinant forms of the two proteins and carried out a comprehensive biochemical and biophysical study of their interaction, complemented by an in vivo localization study. We show that spontaneous proteolysis of MADD-4B first generates a shorter N-MADD-4B form, which comprises four thrombospondin (TSP) domains and one Ig-like domain and binds NLG-1. A second processing event eliminates the C-terminal Ig-like domain along with the ability of N-MADD-4B to bind NLG-1. These data identify the Ig-like domain as the primary determinant for N-MADD-4B interaction with NLG-1 in vitro We further demonstrate in vivo that this Ig-like domain is essential, albeit not sufficient per se, for efficient recruitment of GABAA receptors at GABAergic synapses in C. elegans The interaction of N-MADD-4B with NLG-1 is also disrupted by heparin, used as a surrogate for the extracellular matrix component, heparan sulfate. High-affinity binding of heparin/heparan sulfate to the Ig-like domain may proceed from surface charge complementarity, as suggested by homology three-dimensional modeling. These data point to N-MADD-4B processing and cell-surface proteoglycan binding as two possible mechanisms to regulate the interaction between MADD-4B and NLG-1 at GABAergic synapses.
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Affiliation(s)
- Semeli Platsaki
- CNRS/Aix-Marseille Univ, Laboratory "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Marseille, France
| | - Xin Zhou
- Univ Lyon/Univ Claude Bernard Lyon 1/CNRS/INSERM, Institut NeuroMyoGène (INMG), Lyon, France
| | - Bérangère Pinan-Lucarré
- Univ Lyon/Univ Claude Bernard Lyon 1/CNRS/INSERM, Institut NeuroMyoGène (INMG), Lyon, France
| | - Vincent Delauzun
- CNRS/Aix-Marseille Univ, Laboratory "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Marseille, France
| | - Haijun Tu
- Univ Lyon/Univ Claude Bernard Lyon 1/CNRS/INSERM, Institut NeuroMyoGène (INMG), Lyon, France
| | - Pascal Mansuelle
- CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée (IMM), Marseille Proteomics (MaP), Marseille, France
| | - Patrick Fourquet
- Aix-Marseille Univ/INSERM/CNRS, Institut Paoli-Calmettes, Centre de Recherche en Cancérologie de Marseille (CRCM), Marseille Proteomics (MaP), Marseille, France
| | - Yves Bourne
- CNRS/Aix-Marseille Univ, Laboratory "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Marseille, France
| | - Jean-Louis Bessereau
- Univ Lyon/Univ Claude Bernard Lyon 1/CNRS/INSERM, Institut NeuroMyoGène (INMG), Lyon, France
| | - Pascale Marchot
- CNRS/Aix-Marseille Univ, Laboratory "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Marseille, France.
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27
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Interplay between Anakonda, Gliotactin, and M6 for Tricellular Junction Assembly and Anchoring of Septate Junctions in Drosophila Epithelium. Curr Biol 2020; 30:4245-4253.e4. [PMID: 32857971 DOI: 10.1016/j.cub.2020.07.090] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 11/22/2022]
Abstract
In epithelia, tricellular junctions (TCJs) serve as pivotal sites for barrier function and integration of both biochemical and mechanical signals [1-3]. In Drosophila, TCJs are composed of the transmembrane protein Sidekick at the adherens junction (AJ) level, which plays a role in cell-cell contact rearrangement [4-6]. At the septate junction (SJ) level, TCJs are formed by Gliotactin (Gli) [7], Anakonda (Aka) [8, 9], and the Myelin proteolipid protein (PLP) M6 [10, 11]. Despite previous data on TCJ organization [12-14], TCJ assembly, composition, and links to adjacent bicellular junctions (BCJs) remain poorly understood. Here, we have characterized the making of TCJs within the plane of adherens junctions (tricellular adherens junction [tAJ]) and the plane of septate junctions (tricellular septate junction [tSJ]) and report that their assembly is independent of each other. Aka and M6, whose localizations are interdependent, act upstream to localize Gli. In turn, Gli stabilizes Aka at tSJ. Moreover, tSJ components are not only essential at vertex, as we found that loss of tSJ integrity induces micron-length bicellular SJ (bSJ) deformations. This phenotype is associated with the disappearance of SJ components at tricellular contacts, indicating that bSJs are no longer connected to tSJs. Reciprocally, SJ components are required to restrict the localization of Aka and Gli at vertex. We propose that tSJs function as pillars to anchor bSJs to ensure the maintenance of tissue integrity in Drosophila proliferative epithelia.
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28
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Rudan Njavro J, Klotz J, Dislich B, Wanngren J, Shmueli MD, Herber J, Kuhn PH, Kumar R, Koeglsperger T, Conrad M, Wurst W, Feederle R, Vlachos A, Michalakis S, Jedlicka P, Müller SA, Lichtenthaler SF. Mouse brain proteomics establishes MDGA1 and CACHD1 as in vivo substrates of the Alzheimer protease BACE1. FASEB J 2019; 34:2465-2482. [PMID: 31908000 DOI: 10.1096/fj.201902347r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/22/2019] [Accepted: 12/03/2019] [Indexed: 01/18/2023]
Abstract
The protease beta-site APP cleaving enzyme 1 (BACE1) has fundamental functions in the nervous system. Its inhibition is a major therapeutic approach in Alzheimer's disease, because BACE1 cleaves the amyloid precursor protein (APP), thereby catalyzing the first step in the generation of the pathogenic amyloid beta (Aβ) peptide. Yet, BACE1 cleaves numerous additional membrane proteins besides APP. Most of these substrates have been identified in vitro, but only few were further validated or characterized in vivo. To identify BACE1 substrates with in vivo relevance, we used isotope label-based quantitative proteomics of wild type and BACE1-deficient (BACE1 KO) mouse brains. This approach identified known BACE1 substrates, including Close homolog of L1 and contactin-2, which were found to be enriched in the membrane fraction of BACE1 KO brains. VWFA and cache domain-containing protein 1 (CACHD)1 and MAM domain-containing glycosylphosphatidylinositol anchor protein 1 (MDGA1), which have functions in synaptic transmission, were identified and validated as new BACE1 substrates in vivo by immunoblots using primary neurons and mouse brains. Inhibition or deletion of BACE1 from primary neurons resulted in a pronounced inhibition of substrate cleavage and a concomitant increase in full-length protein levels of CACHD1 and MDGA1. The BACE1 cleavage site in both proteins was determined to be located within the juxtamembrane domain. In summary, this study identifies and validates CACHD1 and MDGA1 as novel in vivo substrates for BACE1, suggesting that cleavage of both proteins may contribute to the numerous functions of BACE1 in the nervous system.
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Affiliation(s)
- Jasenka Rudan Njavro
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jakob Klotz
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Bastian Dislich
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Institute of Pathology, University of Bern, Switzerland
| | - Johanna Wanngren
- Division of Neurogeriatrics, Department of NVS, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Merav D Shmueli
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Julia Herber
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Peer-Hendrik Kuhn
- Institute of Pathology, Technical University of Munich, Munich, Germany
| | - Rohit Kumar
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Department of Neurology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Thomas Koeglsperger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Department of Neurology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Marcus Conrad
- Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Genome Engineering, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Developmental Genetics, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Regina Feederle
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,German Research Center for Environmental Health, Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Zentrum München, Neuherberg, Germany.,Core Facility Monoclonal Antibodies, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Germany.,Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Peter Jedlicka
- Faculty of Medicine, ICAR3R - Interdisciplinary Centre for 3Rs in Animal Research, Justus-Liebig-University, Giessen, Germany.,Neuroscience Center, Institute of Clinical Neuroanatomy, Goethe University, Frankfurt am Main, Germany.,Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
| | - Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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29
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A negative regulator of synaptic development: MDGA and its links to neurodevelopmental disorders. World J Pediatr 2019; 15:415-421. [PMID: 30997654 DOI: 10.1007/s12519-019-00253-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 03/28/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Formation of protein complexes across synapses is a critical process in neurodevelopment, having direct implications on brain function and animal behavior. Here, we present the understanding, importance, and potential impact of a newly found regulator of such a key interaction. DATA SOURCES A systematic search of the literature was conducted on PubMed (Medline), Embase, and Central-Cochrane Database. RESULTS Membrane-associated mucin domain-containing glycosylphosphatidylinositol anchor proteins (MDGAs) were recently discovered to regulate synaptic development and transmission via suppression of neurexins-neuroligins trans-synaptic complex formation. MDGAs also regulate axonal migration and outgrowth. In the context of their physiological role, we begin to consider the potential links to the etiology of certain neurodevelopmental disorders. We present the gene expression and protein structure of MDGAs and discuss recent progress in our understanding of the neurobiological role of MDGAs to explore its potential as a therapeutic target. CONCLUSION MDGAs play a key role in neuron migration, axon guidance and synapse development, as well as in regulating brain excitation and inhibition balance.
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Connor SA, Ammendrup-Johnsen I, Kishimoto Y, Karimi Tari P, Cvetkovska V, Harada T, Ojima D, Yamamoto T, Wang YT, Craig AM. Loss of Synapse Repressor MDGA1 Enhances Perisomatic Inhibition, Confers Resistance to Network Excitation, and Impairs Cognitive Function. Cell Rep 2019; 21:3637-3645. [PMID: 29281813 DOI: 10.1016/j.celrep.2017.11.109] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 10/10/2017] [Accepted: 11/29/2017] [Indexed: 01/27/2023] Open
Abstract
Synaptopathies contributing to neurodevelopmental disorders are linked to mutations in synaptic organizing molecules, including postsynaptic neuroligins, presynaptic neurexins, and MDGAs, which regulate their interaction. The role of MDGA1 in suppressing inhibitory versus excitatory synapses is controversial based on in vitro studies. We show that genetic deletion of MDGA1 in vivo elevates hippocampal CA1 inhibitory, but not excitatory, synapse density and transmission. Furthermore, MDGA1 is selectively expressed by pyramidal neurons and regulates perisomatic, but not distal dendritic, inhibitory synapses. Mdga1-/- hippocampal networks demonstrate muted responses to neural excitation, and Mdga1-/- mice are resistant to induced seizures. Mdga1-/- mice further demonstrate compromised hippocampal long-term potentiation, consistent with observed deficits in spatial and context-dependent learning and memory. These results suggest that mutations in MDGA1 may contribute to cognitive deficits through altered synaptic transmission and plasticity by loss of suppression of inhibitory synapse development in a subcellular domain- and cell-type-selective manner.
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Affiliation(s)
- Steven A Connor
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada; Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ina Ammendrup-Johnsen
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yasushi Kishimoto
- Department of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2101, Japan
| | - Parisa Karimi Tari
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Vedrana Cvetkovska
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Takashi Harada
- Department of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2101, Japan
| | - Daiki Ojima
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa 761-0793, Japan
| | - Tohru Yamamoto
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa 761-0793, Japan
| | - Yu Tian Wang
- Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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Neurexins - versatile molecular platforms in the synaptic cleft. Curr Opin Struct Biol 2019; 54:112-121. [PMID: 30831539 DOI: 10.1016/j.sbi.2019.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 01/05/2023]
Abstract
Neurexins constitute a large family of synaptic organizers. Their extracellular domains protrude into the synaptic cleft where they can form transsynaptic bridges with different partners. A unique constellation of structural elements within their ectodomains enables neurexins to create molecular platforms within the synaptic cleft that permit a large portfolio of partners to be recruited, assembled and their interactions to be dynamically regulated. Neurexins and their partners are implicated in neuropsychiatric diseases including autism spectrum disorder and schizophrenia. Detailed understanding of the mechanisms that underlie neurexin interactions may in future guide the design of tools to manipulate synaptic connections and their function, in particular those involved in the pathogenesis of neuropsychiatric disease.
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Chamma I, Sainlos M, Thoumine O. Biophysical mechanisms underlying the membrane trafficking of synaptic adhesion molecules. Neuropharmacology 2019; 169:107555. [PMID: 30831159 DOI: 10.1016/j.neuropharm.2019.02.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/14/2019] [Accepted: 02/27/2019] [Indexed: 01/13/2023]
Abstract
Adhesion proteins play crucial roles at synapses, not only by providing a physical trans-synaptic linkage between axonal and dendritic membranes, but also by connecting to functional elements including the pre-synaptic neurotransmitter release machinery and post-synaptic receptors. To mediate these functions, adhesion proteins must be organized on the neuronal surface in a precise and controlled manner. Recent studies have started to describe the mobility, nanoscale organization, and turnover rate of key synaptic adhesion molecules including cadherins, neurexins, neuroligins, SynCAMs, and LRRTMs, and show that some of these proteins are highly mobile in the plasma membrane while others are confined at sub-synaptic compartments, providing evidence for different regulatory pathways. In this review article, we provide a biophysical view of the diffusional trapping of adhesion molecules at synapses, involving both extracellular and intracellular protein interactions. We review the methodology underlying these measurements, including biomimetic systems with purified adhesion proteins, means to perturb protein expression or function, single molecule imaging in cultured neurons, and analytical models to interpret the data. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Ingrid Chamma
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France
| | - Matthieu Sainlos
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France
| | - Olivier Thoumine
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France.
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Tomita S. Molecular constituents and localization of the ionotropic GABA receptor complex in vivo. Curr Opin Neurobiol 2019; 57:81-86. [PMID: 30784980 DOI: 10.1016/j.conb.2019.01.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 01/14/2019] [Indexed: 01/24/2023]
Abstract
The ionotropic GABA receptor (GABAAR) mediates fast inhibition in the brain. The GABAAR pore-forming (α, β, and non-α/β) subunits were isolated approximately 30 years ago and have since been the focus of extensive studies. As a result, many properties of GABAARs, including subunit assembly and channel and pharmacological properties, have been discovered. However, several of the underlying mechanisms such as the process for the synaptic localization of GABAARs remain unsolved. A reinvestigation of native GABAAR complexes in the brain and primary neurons identified two major molecular constituents, namely, the transmembrane GARLH/LHFPL protein family and the inhibitory synaptic protein neuroligin 2. This identification of the principal components of native receptor complexes may provide new mechanistic insight on receptor regulation.
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Affiliation(s)
- Susumu Tomita
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, United States.
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Connor SA, Elegheert J, Xie Y, Craig AM. Pumping the brakes: suppression of synapse development by MDGA-neuroligin interactions. Curr Opin Neurobiol 2019; 57:71-80. [PMID: 30771697 DOI: 10.1016/j.conb.2019.01.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 12/22/2022]
Abstract
Synapse development depends on a dynamic balance between synapse promoters and suppressors. MDGAs, immunoglobulin superfamily proteins, negatively regulate synapse development through blocking neuroligin-neurexin interactions. Recent analyses of MDGA-neuroligin complexes revealed the structural basis of this activity and indicate that MDGAs interact with all neuroligins with differential affinities. Surprisingly, analyses of mouse mutants revealed a functional divergence, with targeted mutation of Mdga1 and Mdga2 elevating inhibitory and excitatory synapses, respectively, on hippocampal pyramidal neurons. Further research is needed to determine the synapse-specific organizing properties of MDGAs in neural circuits, which may depend on relative levels and subcellular distributions of each MDGA, neuroligin and neurexin. Behavioral deficits in Mdga mutant mice support genetic links to schizophrenia and autism spectrum disorders and raise the possibility of harnessing these interactions for therapeutic purposes.
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Affiliation(s)
- Steven A Connor
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
| | - Jonathan Elegheert
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Yicheng Xie
- The Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada.
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Abstract
Synapse formation is mediated by a surprisingly large number and wide variety of genes encoding many different protein classes. One of the families increasingly implicated in synapse wiring is the immunoglobulin superfamily (IgSF). IgSF molecules are by definition any protein containing at least one Ig-like domain, making this family one of the most common protein classes encoded by the genome. Here, we review the emerging roles for IgSF molecules in synapse formation specifically in the vertebrate brain, focusing on examples from three classes of IgSF members: ( a) cell adhesion molecules, ( b) signaling molecules, and ( c) immune molecules expressed in the brain. The critical roles for IgSF members in regulating synapse formation may explain their extensive involvement in neuropsychiatric and neurodevelopmental disorders. Solving the IgSF code for synapse formation may reveal multiple new targets for rescuing IgSF-mediated deficits in synapse formation and, eventually, new treatments for psychiatric disorders caused by altered IgSF-induced synapse wiring.
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Affiliation(s)
- Scott Cameron
- Center for Neuroscience, University of California, Davis, California 95618, USA; ,
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36
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Guo R, Li H, Li X, Xue Z, Sun Y, Ma D, Guan Y, Li J, Tian M, Wang Y. Downregulation of neuroligin1 ameliorates postoperative pain through inhibiting neuroligin1/postsynaptic density 95-mediated synaptic targeting of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor GluA1 subunits in rat dorsal horns. Mol Pain 2018; 14:1744806918766745. [PMID: 29592780 PMCID: PMC5881971 DOI: 10.1177/1744806918766745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuroligin1 is an important synaptic cell adhesion molecule that modulates the function of synapses through protein-protein interactions. Yet, it remains unclear whether the regulation of synaptic transmission in the spinal cord by neruoligin1 contributes to the development of postoperative pain. In a rat model of postoperative pain induced by plantar incision, we conducted Western blot study to examine changes in the expression of postsynaptic membrane of neuroligin1, postsynaptic density 95 (PSD-95), and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor GluA1 and GluA2 subunits in the spinal cord dorsal horn after injury. The interaction between neuroligin1 and PSD-95 was further determined by using coimmunoprecipitation. Protein levels of neuroligin1 and GluA1, but not GluA2 and PSD-95, were significantly increased in the postsynaptic membrane of the ipsilateral dorsal horn at 3 h and 1 day after incision, as compared to that in control group (naïve). A greater amount of PSD-95 was coimmunoprecipitated with neuroligin1 at 3 h after incision than that in the control group. Intrathecal administration of small interfering RNAs (siRNAs) targeting neuroligin1 suppressed the expression of neuroligin1 in the spinal cord. Importantly, pretreatment with intrathecal neuroligin1 siRNA2497, but not scrambled siRNA or vehicle, prevented the upregulation of GluA1 expression at 3 h after incision, inhibited the enhanced neuroligin1/PSD-95 interaction, and attenuated postoperative pain. Together, current findings suggest that downregulation of spinal neuroligin1 expression may ameliorate postoperative pain through inhibiting neuroligin1/PSD-95 interaction and synaptic targeting of GluA1 subunit. Accordingly, spinal neuroligin1 may be a potential new target for postoperative pain treatment.
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Affiliation(s)
- Ruijuan Guo
- 1 Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Huili Li
- 2 Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xueyang Li
- 2 Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Zhaojing Xue
- 1 Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yuqing Sun
- 2 Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Danxu Ma
- 2 Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Yun Guan
- 3 Department of Anesthesiology and Critical Care Medicine, The 1466 Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Junfa Li
- 4 Department of Neurobiology, Capital Medical University, Beijing, China
| | - Ming Tian
- 1 Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yun Wang
- 2 Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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37
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Dynamics, nanoscale organization, and function of synaptic adhesion molecules. Mol Cell Neurosci 2018; 91:95-107. [DOI: 10.1016/j.mcn.2018.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 04/12/2018] [Accepted: 04/13/2018] [Indexed: 12/13/2022] Open
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Park D, Bae S, Yoon TH, Ko J. Molecular Mechanisms of Synaptic Specificity: Spotlight on Hippocampal and Cerebellar Synapse Organizers. Mol Cells 2018; 41:373-380. [PMID: 29665671 PMCID: PMC5974614 DOI: 10.14348/molcells.2018.0081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 03/30/2018] [Accepted: 04/02/2018] [Indexed: 12/13/2022] Open
Abstract
Synapses and neural circuits form with exquisite specificity during brain development to allow the precise and appropriate flow of neural information. Although this property of synapses and neural circuits has been extensively investigated for more than a century, molecular mechanisms underlying this property are only recently being unveiled. Recent studies highlight several classes of cell-surface proteins as organizing hubs in building structural and functional architectures of specific synapses and neural circuits. In the present mini-review, we discuss recent findings on various synapse organizers that confer the distinct properties of specific synapse types and neural circuit architectures in mammalian brains, with a particular focus on the hippocampus and cerebellum.
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Affiliation(s)
- Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Sungwon Bae
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Taek Han Yoon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
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Lie E, Li Y, Kim R, Kim E. SALM/Lrfn Family Synaptic Adhesion Molecules. Front Mol Neurosci 2018; 11:105. [PMID: 29674953 PMCID: PMC5895706 DOI: 10.3389/fnmol.2018.00105] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/19/2018] [Indexed: 12/31/2022] Open
Abstract
Synaptic adhesion-like molecules (SALMs) are a family of cell adhesion molecules involved in regulating neuronal and synapse development that have also been implicated in diverse brain dysfunctions, including autism spectrum disorders (ASDs). SALMs, also known as leucine-rich repeat (LRR) and fibronectin III domain-containing (LRFN) proteins, were originally identified as a group of novel adhesion-like molecules that contain LRRs in the extracellular region as well as a PDZ domain-binding tail that couples to PSD-95, an abundant excitatory postsynaptic scaffolding protein. While studies over the last decade have steadily explored the basic properties and synaptic and neuronal functions of SALMs, a number of recent studies have provided novel insights into molecular, structural, functional and clinical aspects of SALMs. Here we summarize these findings and discuss how SALMs act in concert with other synaptic proteins to regulate synapse development and function.
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Affiliation(s)
- Eunkyung Lie
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Yan Li
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Ryunhee Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
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40
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Bourne Y, Marchot P. Hot Spots for Protein Partnerships at the Surface of Cholinesterases and Related α/β Hydrolase Fold Proteins or Domains-A Structural Perspective. Molecules 2017; 23:molecules23010035. [PMID: 29295471 PMCID: PMC5943944 DOI: 10.3390/molecules23010035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/12/2022] Open
Abstract
The hydrolytic enzymes acetyl- and butyryl-cholinesterase, the cell adhesion molecules neuroligins, and the hormonogenic macromolecule thyroglobulin are a few of the many members of the α/β hydrolase fold superfamily of proteins. Despite their distinctive functions, their canonical subunits, with a molecular surface area of ~20,000 Å2, they share binding patches and determinants for forming homodimers and for accommodating structural subunits or protein partners. Several of these surface regions of high functional relevance have been mapped through structural or mutational studies, while others have been proposed based on biochemical data or molecular docking studies. Here, we review these binding interfaces and emphasize their specificity versus potentially multifunctional character.
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Affiliation(s)
- Yves Bourne
- Centre National de la Recherche Scientifique, Aix-Marseille Université, "Architecture et Fonction des Macromolécules Biologiques" Laboratory, 13288 Marseille, France.
| | - Pascale Marchot
- Centre National de la Recherche Scientifique, Aix-Marseille Université, "Architecture et Fonction des Macromolécules Biologiques" Laboratory, 13288 Marseille, France.
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41
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Südhof TC. Synaptic Neurexin Complexes: A Molecular Code for the Logic of Neural Circuits. Cell 2017; 171:745-769. [PMID: 29100073 DOI: 10.1016/j.cell.2017.10.024] [Citation(s) in RCA: 471] [Impact Index Per Article: 67.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/04/2017] [Accepted: 10/15/2017] [Indexed: 10/18/2022]
Abstract
Synapses are specialized junctions between neurons in brain that transmit and compute information, thereby connecting neurons into millions of overlapping and interdigitated neural circuits. Here, we posit that the establishment, properties, and dynamics of synapses are governed by a molecular logic that is controlled by diverse trans-synaptic signaling molecules. Neurexins, expressed in thousands of alternatively spliced isoforms, are central components of this dynamic code. Presynaptic neurexins regulate synapse properties via differential binding to multifarious postsynaptic ligands, such as neuroligins, cerebellin/GluD complexes, and latrophilins, thereby shaping the input/output relations of their resident neural circuits. Mutations in genes encoding neurexins and their ligands are associated with diverse neuropsychiatric disorders, especially schizophrenia, autism, and Tourette syndrome. Thus, neurexins nucleate an overall trans-synaptic signaling network that controls synapse properties, which thereby determines the precise responses of synapses to spike patterns in a neuron and circuit and which is vulnerable to impairments in neuropsychiatric disorders.
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Affiliation(s)
- Thomas C Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, CA 94305-5453, USA.
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Abstract
At each of the brain's vast number of synapses, the presynaptic nerve terminal, synaptic cleft, and postsynaptic specialization form a transcellular unit to enable efficient transmission of information between neurons. While we know much about the molecular machinery within each compartment, we are only beginning to understand how these compartments are structurally registered and functionally integrated with one another. This review will describe the organization of each compartment and then discuss their alignment across pre- and postsynaptic cells at a nanometer scale. We propose that this architecture may allow for precise synaptic information exchange and may be modulated to contribute to the remarkable plasticity of brain function.
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Affiliation(s)
- Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Biederer T, Kaeser PS, Blanpied TA. Transcellular Nanoalignment of Synaptic Function. Neuron 2017; 96:680-696. [PMID: 29096080 PMCID: PMC5777221 DOI: 10.1016/j.neuron.2017.10.006] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/29/2017] [Accepted: 10/03/2017] [Indexed: 12/21/2022]
Abstract
At each of the brain's vast number of synapses, the presynaptic nerve terminal, synaptic cleft, and postsynaptic specialization form a transcellular unit to enable efficient transmission of information between neurons. While we know much about the molecular machinery within each compartment, we are only beginning to understand how these compartments are structurally registered and functionally integrated with one another. This review will describe the organization of each compartment and then discuss their alignment across pre- and postsynaptic cells at a nanometer scale. We propose that this architecture may allow for precise synaptic information exchange and may be modulated to contribute to the remarkable plasticity of brain function.
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Affiliation(s)
- Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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44
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Abstract
Neurexins and neuroligins form trans-synaptic complexes that promote synapse development. In this issue of Neuron, Aricescu and colleagues (Elegheert et al., 2017) complement and strengthen two recent reports by the Kim and Rudenko teams (Kim et al., 2017; Gangwar et al., 2017) to dissect the molecular determinants by which MDGAs challenge the neurexin-neuroligin partnership.
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Affiliation(s)
- Olivier Thoumine
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, University of Bordeaux, 33000 Bordeaux, France.
| | - Pascale Marchot
- Centre National de la Recherche Scientifique, Aix-Marseille Université, "Architecture et Fonction des Macromolécules Biologiques" laboratory, Faculté des Sciences de Luminy, 13288 Marseille, France.
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45
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Neural Glycosylphosphatidylinositol-Anchored Proteins in Synaptic Specification. Trends Cell Biol 2017; 27:931-945. [PMID: 28743494 DOI: 10.1016/j.tcb.2017.06.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 12/15/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins are a specialized class of lipid-associated neuronal membrane proteins that perform diverse functions in the dynamic control of axon guidance, synaptic adhesion, cytoskeletal remodeling, and localized signal transduction, particularly at lipid raft domains. Recent studies have demonstrated that a subset of GPI-anchored proteins act as critical regulators of synapse development by modulating specific synaptic adhesion pathways via direct interactions with key synapse-organizing proteins. Additional studies have revealed that alteration of these regulatory mechanisms may underlie various brain disorders. In this review, we highlight the emerging role of GPI-anchored proteins as key synapse organizers that aid in shaping the properties of various types of synapses and circuits in mammals.
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