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Hauser D, Behr K, Konno K, Schreiner D, Schmidt A, Watanabe M, Bischofberger J, Scheiffele P. Targeted proteoform mapping uncovers specific Neurexin-3 variants required for dendritic inhibition. Neuron 2022; 110:2094-2109.e10. [PMID: 35550065 PMCID: PMC9275415 DOI: 10.1016/j.neuron.2022.04.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 02/05/2022] [Accepted: 04/15/2022] [Indexed: 12/21/2022]
Abstract
The diversification of cell adhesion molecules by alternative splicing is proposed to underlie molecular codes for neuronal wiring. Transcriptomic approaches mapped detailed cell-type-specific mRNA splicing programs. However, it has been hard to probe the synapse-specific localization and function of the resulting protein splice isoforms, or “proteoforms,” in vivo. We here apply a proteoform-centric workflow in mice to test the synapse-specific functions of the splice isoforms of the synaptic adhesion molecule Neurexin-3 (NRXN3). We uncover a major proteoform, NRXN3 AS5, that is highly expressed in GABAergic interneurons and at dendrite-targeting GABAergic terminals. NRXN3 AS5 abundance significantly diverges from Nrxn3 mRNA distribution and is gated by translation-repressive elements. Nrxn3 AS5 isoform deletion results in a selective impairment of dendrite-targeting interneuron synapses in the dentate gyrus without affecting somatic inhibition or glutamatergic perforant-path synapses. This work establishes cell- and synapse-specific functions of a specific neurexin proteoform and highlights the importance of alternative splicing regulation for synapse specification. Translational regulation guides alternative Neurexin proteoform expression NRXN3 AS5 proteoforms are concentrated at dendrite-targeting interneuron synapses A proteome-centric workflow uncovers NRXN3 AS5 interactors in vivo Loss of NRXN3 AS5 leads to selective impairments in dendritic inhibition
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Affiliation(s)
- David Hauser
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Katharina Behr
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Kohtarou Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Dietmar Schreiner
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Alexander Schmidt
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Josef Bischofberger
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Peter Scheiffele
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.
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2
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Karki S, Kajander T. Crystallization and low-resolution structure solution of the SALM3-PTPσ synaptic adhesion complex. Acta Crystallogr F Struct Biol Commun 2022; 78:39-44. [PMID: 34981774 PMCID: PMC8725006 DOI: 10.1107/s2053230x21012905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/03/2021] [Indexed: 01/03/2023] Open
Abstract
Synaptic adhesion molecules are major organizers of the neuronal network and play a crucial role in the regulation of synapse development and maintenance in the brain. Synaptic adhesion-like molecules (SALMs) and leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-PTPs) are adhesion protein families with established synaptic function. Dysfunction of several synaptic adhesion molecules has been linked to cognitive disorders such as autism spectrum disorders and schizophrenia. A recent study of the binding and complex structure of SALM3 and PTPσ using small-angle X-ray scattering revealed a 2:2 complex similar to that observed for the interaction of human SALM5 and PTPδ. However, the molecular structure of the SALM3-PTPσ complex remains to be determined beyond the small-angle X-ray scattering model. Here, the expression, purification, crystallization and initial 6.5 Å resolution structure of the mouse SALM3-PTPσ complex are reported, which further verifies the formation of a 2:2 trans-heterotetrameric complex similar to the crystal structure of human SALM5-PTPδ and validates the architecture of the previously reported small-angle scattering-based solution structure of the SALM3-PTPσ complex. Details of the protein expression and purification, crystal optimization trials, and the initial structure solution and data analysis are provided.
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Affiliation(s)
- Sudeep Karki
- Institute of Biotechnology, Helsinki Institute of Life Sciences, University of Helsinki, Viikinkaari 1, 00014 Helsinki, Finland
| | - Tommi Kajander
- Institute of Biotechnology, Helsinki Institute of Life Sciences, University of Helsinki, Viikinkaari 1, 00014 Helsinki, Finland,Correspondence e-mail:
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Soheili-Nezhad S, van der Linden RJ, Olde Rikkert M, Sprooten E, Poelmans G. Long genes are more frequently affected by somatic mutations and show reduced expression in Alzheimer's disease: Implications for disease etiology. Alzheimers Dement 2020; 17:489-499. [PMID: 33075204 PMCID: PMC8048495 DOI: 10.1002/alz.12211] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/11/2020] [Accepted: 10/21/2020] [Indexed: 12/17/2022]
Abstract
Aging, the greatest risk factor for Alzheimer's disease (AD), may lead to the accumulation of somatic mutations in neurons. We investigated whether somatic mutations, specifically in longer genes, are implicated in AD etiology. First, we modeled the theoretical likelihood of genes being affected by aging‐induced somatic mutations, dependent on their length. We then tested this model and found that long genes are indeed more affected by somatic mutations and that their expression is more frequently reduced in AD brains. Furthermore, using gene‐set enrichment analysis, we investigated the potential consequences of such long gene disruption. We found that long genes are involved in synaptic adhesion and other synaptic pathways that are predicted to be inhibited in the brains of AD patients. Taken together, our findings indicate that long gene–dependent synaptic impairment may contribute to AD pathogenesis.
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Affiliation(s)
- Sourena Soheili-Nezhad
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Marcel Olde Rikkert
- Department of Geriatric Medicine, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboudumc Alzheimer Center, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Emma Sprooten
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Geert Poelmans
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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4
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Han KA, Kim YJ, Yoon TH, Kim H, Bae S, Um JW, Choi SY, Ko J. LAR-RPTPs Directly Interact with Neurexins to Coordinate Bidirectional Assembly of Molecular Machineries. J Neurosci 2020; 40:8438-62. [PMID: 33037075 DOI: 10.1523/JNEUROSCI.1091-20.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/27/2020] [Accepted: 09/30/2020] [Indexed: 11/21/2022] Open
Abstract
Neurexins (Nrxns) and LAR-RPTPs (leukocyte common antigen-related protein tyrosine phosphatases) are presynaptic adhesion proteins responsible for organizing presynaptic machineries through interactions with nonoverlapping extracellular ligands. Here, we report that two members of the LAR-RPTP family, PTPσ and PTPδ, are required for the presynaptogenic activity of Nrxns. Intriguingly, Nrxn1 and PTPσ require distinct sets of intracellular proteins for the assembly of specific presynaptic terminals. In addition, Nrxn1α showed robust heparan sulfate (HS)-dependent, high-affinity interactions with Ig domains of PTPσ that were regulated by the splicing status of PTPσ. Furthermore, Nrxn1α WT, but not a Nrxn1α mutant lacking HS moieties (Nrxn1α ΔHS), inhibited postsynapse-inducing activity of PTPσ at excitatory, but not inhibitory, synapses. Similarly, cis expression of Nrxn1α WT, but not Nrxn1α ΔHS, suppressed the PTPσ-mediated maintenance of excitatory postsynaptic specializations in mouse cultured hippocampal neurons. Lastly, genetics analyses using male or female Drosophila Dlar and Dnrx mutant larvae identified epistatic interactions that control synapse formation and synaptic transmission at neuromuscular junctions. Our results suggest a novel synaptogenesis model whereby different presynaptic adhesion molecules combine with distinct regulatory codes to orchestrate specific synaptic adhesion pathways.SIGNIFICANCE STATEMENT We provide evidence supporting the physical interactions of neurexins with leukocyte common-antigen related receptor tyrosine phosphatases (LAR-RPTPs). The availability of heparan sulfates and alternative splicing of LAR-RPTPs regulate the binding affinity of these interactions. A set of intracellular presynaptic proteins is involved in common for Nrxn- and LAR-RPTP-mediated presynaptic assembly. PTPσ triggers glutamatergic and GABAergic postsynaptic differentiation in an alternative splicing-dependent manner, whereas Nrxn1α induces GABAergic postsynaptic differentiation in an alternative splicing-independent manner. Strikingly, Nrxn1α inhibits the glutamatergic postsynapse-inducing activity of PTPσ, suggesting that PTPσ and Nrxn1α might control recruitment of a different pool of postsynaptic machinery. Drosophila orthologs of Nrxns and LAR-RPTPs mediate epistatic interactions in controlling synapse structure and strength at neuromuscular junctions, underscoring the physiological significance in vivo.
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Kim H, Kim D, Kim J, Lee HY, Park D, Kang H, Matsuda K, Sterky FH, Yuzaki M, Kim JY, Choi SY, Ko J, Um JW. Calsyntenin-3 interacts with both α- and β-neurexins in the regulation of excitatory synaptic innervation in specific Schaffer collateral pathways. J Biol Chem 2020; 295:9244-9262. [PMID: 32434929 PMCID: PMC7335786 DOI: 10.1074/jbc.ra120.013077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/15/2020] [Indexed: 12/13/2022] Open
Abstract
Calsyntenin-3 (Clstn3) is a postsynaptic adhesion molecule that induces presynaptic differentiation via presynaptic neurexins (Nrxns), but whether Nrxns directly bind to Clstn3 has been a matter of debate. Here, using LC-MS/MS-based protein analysis, confocal microscopy, RNAscope assays, and electrophysiological recordings, we show that β-Nrxns directly interact via their LNS domain with Clstn3 and Clstn3 cadherin domains. Expression of splice site 4 (SS4) insert-positive β-Nrxn variants, but not insert-negative variants, reversed the impaired Clstn3 synaptogenic activity observed in Nrxn-deficient neurons. Consistently, Clstn3 selectively formed complexes with SS4-positive Nrxns in vivo Neuron-specific Clstn3 deletion caused significant reductions in number of excitatory synaptic inputs. Moreover, expression of Clstn3 cadherin domains in CA1 neurons of Clstn3 conditional knockout mice rescued structural deficits in excitatory synapses, especially within the stratum radiatum layer. Collectively, our results suggest that Clstn3 links to SS4-positive Nrxns to induce presynaptic differentiation and orchestrate excitatory synapse development in specific hippocampal neural circuits, including Schaffer collateral afferents.
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Affiliation(s)
- Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea
| | - Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea
| | - Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea
| | - Hee-Yoon Lee
- Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea
| | - Hyeyeon Kang
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea
| | - Keiko Matsuda
- Department of Physiology, School of Medicine, Keio University, Tokyo, Japan
| | - Fredrik H Sterky
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden; Department of Laboratory Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo, Japan
| | - Jin Young Kim
- Biomedical Omics Group, Korea Basic Science Institute, Cheongju, Chungbuk, Korea
| | - Se-Young Choi
- Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea.
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-gun, Daegu, Korea; Core Protein Resources Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-Gun, Daegu, Korea.
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6
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Soheili-Nezhad S, Jahanshad N, Guelfi S, Khosrowabadi R, Saykin AJ, Thompson PM, Beckmann CF, Sprooten E, Zarei M. Imaging genomics discovery of a new risk variant for Alzheimer's disease in the postsynaptic SHARPIN gene. Hum Brain Mapp 2020; 41:3737-3748. [PMID: 32558014 PMCID: PMC7416020 DOI: 10.1002/hbm.25083] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/29/2020] [Accepted: 05/14/2020] [Indexed: 12/26/2022] Open
Abstract
Molecular mechanisms underlying Alzheimer's disease (AD) are difficult to investigate, partly because diagnosis lags behind the insidious pathological processes. Therefore, identifying AD neuroimaging markers and their genetic modifiers may help study early mechanisms of neurodegeneration. We aimed to identify brain regions of the highest vulnerability to AD using a data-driven search in the AD Neuroimaging Initiative (ADNI, n = 1,100 subjects), and further explored genetic variants affecting this critical brain trait using both ADNI and the younger UK Biobank cohort (n = 8,428 subjects). Tensor-Based Morphometry (TBM) and Independent Component Analysis (ICA) identified the limbic system and its interconnecting white-matter as the most AD-vulnerable brain feature. Whole-genome analysis revealed a common variant in SHARPIN that was associated with this imaging feature (rs34173062, p = 2.1 × 10-10 ). This genetic association was validated in the UK Biobank, where it was correlated with entorhinal cortical thickness bilaterally (p = .002 left and p = 8.6 × 10-4 right), and with parental history of AD (p = 2.3 × 10-6 ). Our findings suggest that neuroanatomical variation in the limbic system and AD risk are associated with a novel variant in SHARPIN. The role of this postsynaptic density gene product in β1-integrin adhesion is in line with the amyloid precursor protein (APP) intracellular signaling pathway and the recent genome-wide evidence.
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Affiliation(s)
- Sourena Soheili-Nezhad
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran.,Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands.,Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - Neda Jahanshad
- Imaging Genetics Center, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Marina del Rey, California, USA
| | - Sebastian Guelfi
- Reta Lila Weston Research Laboratories, Department of Molecular Neuroscience, University College London (UCL) Institute of Neurology, London, UK
| | - Reza Khosrowabadi
- Institute for Cognitive and Brain Science, Shahid Beheshti University, Tehran, Iran
| | - Andrew J Saykin
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Paul M Thompson
- Imaging Genetics Center, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Marina del Rey, California, USA
| | - Christian F Beckmann
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands.,Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands.,Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - Emma Sprooten
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Mojtaba Zarei
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
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7
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Park H, Choi Y, Jung H, Kim S, Lee S, Han H, Kweon H, Kang S, Sim WS, Koopmans F, Yang E, Kim H, Smit AB, Bae YC, Kim E. Splice-dependent trans-synaptic PTPδ-IL1RAPL1 interaction regulates synapse formation and non-REM sleep. EMBO J 2020; 39:e104150. [PMID: 32347567 PMCID: PMC7265247 DOI: 10.15252/embj.2019104150] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/17/2020] [Accepted: 03/23/2020] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing regulates trans‐synaptic adhesions and synapse development, but supporting in vivo evidence is limited. PTPδ, a receptor tyrosine phosphatase adhering to multiple synaptic adhesion molecules, is associated with various neuropsychiatric disorders; however, its in vivo functions remain unclear. Here, we show that PTPδ is mainly present at excitatory presynaptic sites by endogenous PTPδ tagging. Global PTPδ deletion in mice leads to input‐specific decreases in excitatory synapse development and strength. This involves tyrosine dephosphorylation and synaptic loss of IL1RAPL1, a postsynaptic partner of PTPδ requiring the PTPδ‐meA splice insert for binding. Importantly, PTPδ‐mutant mice lacking the PTPδ‐meA insert, and thus lacking the PTPδ interaction with IL1RAPL1 but not other postsynaptic partners, recapitulate biochemical and synaptic phenotypes of global PTPδ‐mutant mice. Behaviorally, both global and meA‐specific PTPδ‐mutant mice display abnormal sleep behavior and non‐REM rhythms. Therefore, alternative splicing in PTPδ regulates excitatory synapse development and sleep by modulating a specific trans‐synaptic adhesion.
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Affiliation(s)
- Haram Park
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Yeonsoo Choi
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hwajin Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Seoyeong Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hyemin Han
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Hanseul Kweon
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suwon Kang
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Woong Seob Sim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Frank Koopmans
- Department of Functional Genomics, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands.,Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea.,Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
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8
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Kim K, Shin W, Kang M, Lee S, Kim D, Kang R, Jung Y, Cho Y, Yang E, Kim H, Bae YC, Kim E. Presynaptic PTPσ regulates postsynaptic NMDA receptor function through direct adhesion-independent mechanisms. eLife 2020; 9:54224. [PMID: 32142410 PMCID: PMC7069723 DOI: 10.7554/elife.54224] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/04/2020] [Indexed: 12/14/2022] Open
Abstract
Synaptic adhesion molecules regulate synapse development and function. However, whether and how presynaptic adhesion molecules regulate postsynaptic NMDAR function remains largely unclear. Presynaptic LAR family receptor tyrosine phosphatases (LAR-RPTPs) regulate synapse development through mechanisms that include trans-synaptic adhesion; however, whether they regulate postsynaptic receptor functions remains unknown. Here we report that presynaptic PTPσ, a LAR-RPTP, enhances postsynaptic NMDA receptor (NMDAR) currents and NMDAR-dependent synaptic plasticity in the hippocampus. This regulation does not involve trans-synaptic adhesions of PTPσ, suggesting that the cytoplasmic domains of PTPσ, known to have tyrosine phosphatase activity and mediate protein-protein interactions, are important. In line with this, phosphotyrosine levels of presynaptic proteins, including neurexin-1, are strongly increased in PTPσ-mutant mice. Behaviorally, PTPσ-dependent NMDAR regulation is important for social and reward-related novelty recognition. These results suggest that presynaptic PTPσ regulates postsynaptic NMDAR function through trans-synaptic and direct adhesion-independent mechanisms and novelty recognition in social and reward contexts.
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Affiliation(s)
- Kyungdeok Kim
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Wangyong Shin
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea.,Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Muwon Kang
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Doyoun Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Ryeonghwa Kang
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Yewon Jung
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Yisul Cho
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Eunjoon Kim
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea.,Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Republic of Korea
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9
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Roppongi RT, Dhume SH, Padmanabhan N, Silwal P, Zahra N, Karimi B, Bomkamp C, Patil CS, Champagne-Jorgensen K, Twilley RE, Zhang P, Jackson MF, Siddiqui TJ. LRRTMs Organize Synapses through Differential Engagement of Neurexin and PTPσ. Neuron 2020; 106:108-125.e12. [PMID: 31995730 DOI: 10.1016/j.neuron.2020.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 08/07/2019] [Accepted: 01/02/2020] [Indexed: 02/07/2023]
Abstract
Presynaptic neurexins (Nrxs) and type IIa receptor-type protein tyrosine phosphatases (RPTPs) organize synapses through a network of postsynaptic ligands. We show that leucine-rich-repeat transmembrane neuronal proteins (LRRTMs) differentially engage the protein domains of Nrx but require its heparan sulfate (HS) modification to induce presynaptic differentiation. Binding to the HS of Nrx is sufficient for LRRTM3 and LRRTM4 to induce synaptogenesis. We identify mammalian Nrx1γ as a potent synapse organizer and reveal LRRTM4 as its postsynaptic ligand. Mice expressing a mutant form of LRRTM4 that cannot bind to HS show structural and functional deficits at dentate gyrus excitatory synapses. Through the HS of Nrx, LRRTMs also recruit PTPσ to induce presynaptic differentiation but function to varying degrees in its absence. PTPσ forms a robust complex with Nrx, revealing an unexpected interaction between the two presynaptic hubs. These findings underscore the complex interplay of synapse organizers in specifying the molecular logic of a neural circuit.
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Affiliation(s)
- Reiko T Roppongi
- Neuroscience Research Program, 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
| | - Shreya H Dhume
- Neuroscience Research Program, 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
| | - Nirmala Padmanabhan
- Neuroscience Research Program, 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
| | - Prabhisha Silwal
- Neuroscience Research Program, 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
| | - Nazmeena Zahra
- Neuroscience Research Program, 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
| | - Benyamin Karimi
- Neuroscience Research Program, 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
| | - Claire Bomkamp
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B, Canada
| | - Chetan S Patil
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, MB R3E 0Z3, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada
| | - Kevin Champagne-Jorgensen
- Neuroscience Research Program, 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
| | - Rebecca E Twilley
- Neuroscience Research Program, 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
| | - Peng Zhang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B, Canada
| | - Michael F Jackson
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, MB R3E 0Z3, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada
| | - Tabrez J Siddiqui
- Neuroscience Research Program, 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.
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10
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Dagar S, Gottmann K. Differential Properties of the Synaptogenic Activities of the Neurexin Ligands Neuroligin1 and LRRTM2. Front Mol Neurosci 2019; 12:269. [PMID: 31780894 PMCID: PMC6856695 DOI: 10.3389/fnmol.2019.00269] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/22/2019] [Indexed: 12/03/2022] Open
Abstract
Synaptic cell adhesion molecules are well established to exhibit synaptogenic activity when overexpressed in target cells, indicating that they are involved in formation and functional maturation of synapses. The postsynaptic adhesion proteins Neuroligin1 and LRRTM2 both induce synaptic vesicle clusters in presynaptic axons in vitro by transsynaptically interacting with neurexins. In neurons, this is accompanied by the induction of glutamatergic, but not GABAergic synapses. Although the synaptogenic activity of Neuroligin1 has been well characterized, the properties of the synaptogenic activities of other synaptic adhesion molecules are largely unknown. In this paper, we now compared characteristics of the synaptogenic activities of Neuroligin1 and LRRTM2 upon overexpression in cultured mouse cortical neurons. Individual cortical neurons were transfected with Neuroligin1 and LRRTM2 expression plasmids, respectively, and synaptic vesicle clustering in contacting axons was examined by immunostaining for the vesicle membrane protein VAMP2. In immature neurons at 6–7 days in vitro (DIV) both Neuroligin1 and LRRTM2 exhibited strong synaptogenic activity. However, upon further neuronal differentiation only LRRTM2 retained significant synaptogenic activity at 12–13 DIV. A similar differential developmental maturation of the synaptogenic activities of Neuroligin1 and LRRTM2 was observed for the induction of glutamatergic synapses, which were detected by co-immunostaining for VGLUT1 and Homer1. Most interestingly, the synaptogenic activity of Neuroligin1 was strongly dependent on the expression and function of the synaptic adhesion molecule N-cadherin in immature neurons. In contrast, the synaptogenic activity of LRRTM2 was independent of N-cadherin expression and function in both immature (6–7 DIV) and more mature neurons (14–15 DIV). Taken together, our results with overexpression in cultured cortical neurons revealed striking differences in the properties of the synaptogenic activities of Neuroligin1 and LRRTM2, although both transsynaptically interact with presynaptic neurexins.
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Affiliation(s)
- Sushma Dagar
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Kurt Gottmann
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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11
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West RJH, Briggs L, Perona Fjeldstad M, Ribchester RR, Sweeney ST. Sphingolipids regulate neuromuscular synapse structure and function in Drosophila. J Comp Neurol 2018; 526:1995-2009. [PMID: 29761896 PMCID: PMC6175220 DOI: 10.1002/cne.24466] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/10/2018] [Accepted: 04/10/2018] [Indexed: 12/27/2022]
Abstract
Sphingolipids are found in abundance at synapses and have been implicated in regulation of synapse structure, function, and degeneration. Their precise role in these processes, however, remains obscure. Serine Palmitoyl-transferase (SPT) is the first enzymatic step for synthesis of sphingolipids. Analysis of the Drosophila larval neuromuscular junction (NMJ) revealed mutations in the SPT enzyme subunit, lace/SPTLC2 resulted in deficits in synaptic structure and function. Although NMJ length is normal in lace mutants, the number of boutons per NMJ is reduced to ∼50% of the wild type number. Synaptic boutons in lace mutants are much larger but show little perturbation to the general ultrastructure. Electrophysiological analysis of lace mutant synapses revealed strong synaptic transmission coupled with predominance of depression over facilitation. The structural and functional phenotypes of lace mirrored aspects of Basigin (Bsg), a small Ig-domain adhesion molecule also known to regulate synaptic structure and function. Mutant combinations of lace and Bsg generated large synaptic boutons, while lace mutants showed abnormal accumulation of Bsg at synapses, suggesting that Bsg requires sphingolipid to regulate structure of the synapse. In support of this, we found Bsg to be enriched in lipid rafts. Our data points to a role for sphingolipids in the regulation and fine-tuning of synaptic structure and function while sphingolipid regulation of synaptic structure may be mediated via the activity of Bsg.
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Affiliation(s)
- Ryan J. H. West
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
| | - Laura Briggs
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
| | - Maria Perona Fjeldstad
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Discovery Brain SciencesUniversity of EdinburghEdinburgh EH8 9JZUK
| | - Richard R. Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Discovery Brain SciencesUniversity of EdinburghEdinburgh EH8 9JZUK
| | - Sean T. Sweeney
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
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12
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Schroeder A, Vanderlinden J, Vints K, Ribeiro LF, Vennekens KM, Gounko NV, Wierda KD, de Wit J. A Modular Organization of LRR Protein-Mediated Synaptic Adhesion Defines Synapse Identity. Neuron 2018; 99:329-344.e7. [PMID: 29983322 DOI: 10.1016/j.neuron.2018.06.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 05/04/2018] [Accepted: 06/14/2018] [Indexed: 10/28/2022]
Abstract
Pyramidal neurons express rich repertoires of leucine-rich repeat (LRR)-containing adhesion molecules with similar synaptogenic activity in culture. The in vivo relevance of this molecular diversity is unclear. We show that hippocampal CA1 pyramidal neurons express multiple synaptogenic LRR proteins that differentially distribute to the major excitatory inputs on their apical dendrites. At Schaffer collateral (SC) inputs, FLRT2, LRRTM1, and Slitrk1 are postsynaptically localized and differentially regulate synaptic structure and function. FLRT2 controls spine density, whereas LRRTM1 and Slitrk1 exert opposing effects on synaptic vesicle distribution at the active zone. All LRR proteins differentially affect synaptic transmission, and their combinatorial loss results in a cumulative phenotype. At temporoammonic (TA) inputs, LRRTM1 is absent; FLRT2 similarly controls functional synapse number, whereas Slitrk1 function diverges to regulate postsynaptic AMPA receptor density. Thus, LRR proteins differentially control synaptic architecture and function and act in input-specific combinations and a context-dependent manner to specify synaptic properties.
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Affiliation(s)
- Anna Schroeder
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Jeroen Vanderlinden
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Katlijn Vints
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium; Electron Microscopy Platform & VIB BioImaging Core, Herestraat 49, 3000 Leuven, Belgium
| | - Luís F Ribeiro
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Kristel M Vennekens
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Natalia V Gounko
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium; Electron Microscopy Platform & VIB BioImaging Core, Herestraat 49, 3000 Leuven, Belgium
| | - Keimpe D Wierda
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium.
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Servián-Morilla E, Robles-Lanuza E, Sánchez-Hidalgo AC, Camacho-Garcia RJ, Paez-Gomez JA, Mavillard F, Saura CA, Martinez-Mir A, Scholl FG. Proteolytic Processing of Neurexins by Presenilins Sustains Synaptic Vesicle Release. J Neurosci 2018; 38:901-17. [PMID: 29229705 DOI: 10.1523/JNEUROSCI.1357-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 11/03/2017] [Accepted: 11/26/2017] [Indexed: 11/21/2022] Open
Abstract
Proteolytic processing of synaptic adhesion components can accommodate the function of synapses to activity-dependent changes. The adhesion system formed by neurexins (Nrxns) and neuroligins (Nlgns) bidirectionally orchestrate the function of presynaptic and postsynaptic terminals. Previous studies have shown that presenilins (PS), components of the gamma-secretase complex frequently mutated in familial Alzheimer's disease, clear from glutamatergic terminals the accumulation of Nrxn C-terminal fragments (Nrxn-CTF) generated by ectodomain shedding. Here, we characterized the synaptic consequences of the proteolytic processing of Nrxns in cultured hippocampal neurons from mice and rats of both sexes. We show that activation of presynaptic Nrxns with postsynaptic Nlgn1 or inhibition of ectodomain shedding in axonal Nrxn1-β increases presynaptic release at individual terminals, likely reflecting an increase in the number of functional release sites. Importantly, inactivation of PS inhibits presynaptic release downstream of Nrxn activation, leaving synaptic vesicle recruitment unaltered. Glutamate-receptor signaling initiates the activity-dependent generation of Nrxn-CTF, which accumulate at presynaptic terminals lacking PS function. The sole expression of Nrxn-CTF decreases presynaptic release and calcium flux, recapitulating the deficits due to loss of PS function. Our data indicate that inhibition of Nrxn processing by PS is deleterious to glutamatergic function.SIGNIFICANCE STATEMENT To gain insight into the role of presenilins (PS) in excitatory synaptic function, we address the relevance of the proteolytic processing of presynaptic neurexins (Nrxns) in glutamatergic differentiation. Using synaptic fluorescence probes in cultured hippocampal neurons, we report that trans-synaptic activation of Nrxns produces a robust increase in presynaptic calcium levels and neurotransmitter release at individual glutamatergic terminals by a mechanism that depends on normal PS activity. Abnormal accumulation of Nrxn C-terminal fragments resulting from impaired PS activity inhibits presynaptic calcium signal and neurotransmitter release, assigning synaptic defects to Nrxns as a specific PS substrate. These data may provide links into how loss of PS activity inhibits glutamatergic synaptic function in Alzheimer's disease patients.
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15
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Kim JA, Kim D, Won SY, Han KA, Park D, Cho E, Yun N, An HJ, Um JW, Kim E, Lee JO, Ko J, Kim HM. Structural Insights into Modulation of Neurexin-Neuroligin Trans- synaptic Adhesion by MDGA1/Neuroligin-2 Complex. Neuron 2017. [PMID: 28641111 DOI: 10.1016/j.neuron.2017.05.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane-associated mucin domain-containing glycosylphosphatidylinositol anchor proteins (MDGAs) bind directly to neuroligin-1 (NL1) and neuroligin-2 (NL2), thereby respectively regulating excitatory and inhibitory synapse development. However, the mechanisms by which MDGAs modulate NL activity to specify development of the two synapse types remain unclear. Here, we determined the crystal structures of human NL2/MDGA1 Ig1-3 complex, revealing their stable 2:2 arrangement with three interaction interfaces. Cell-based assays using structure-guided, site-directed MDGA1 mutants showed that all three contact patches were required for the MDGA's negative regulation of NL2-mediated synaptogenic activity. Furthermore, MDGA1 competed with neurexins for NL2 via its Ig1 domain. The binding affinities of both MDGA1 and MDGA2 for NL1 and NL2 were similar, consistent with the structural prediction of similar binding interfaces. However, MDGA1 selectively associated with NL2, but not NL1, in vivo. These findings collectively provide structural insights into the mechanism by which MDGAs negatively modulate synapse development governed by NLs/neurexins.
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Affiliation(s)
- Jung A Kim
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Doyoun Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 34141, Korea
| | | | - Kyung Ah Han
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Dongseok Park
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Eunju Cho
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Nayoung Yun
- Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Korea
| | - Hyun Joo An
- Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Korea
| | - Ji Won Um
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 34141, Korea; Department of Biological Sciences, KAIST, Daejeon 34141, Korea
| | - Jie-Oh Lee
- Department of Chemistry, KAIST, Daejeon 34141, Korea
| | - Jaewon Ko
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Ho Min Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 34141, Korea; Graduate School of Medical Science & Engineering, KAIST, Daejeon 34141, Korea.
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16
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Um JW, Ko J. Neural Glycosylphosphatidylinositol-Anchored Proteins in Synaptic Specification. Trends Cell Biol 2017; 27:931-45. [PMID: 28743494 DOI: 10.1016/j.tcb.2017.06.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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17
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Abstract
Leukocyte common antigen-related receptor tyrosine phosphatases (LAR-RPTPs) have emerged as key players that organize various aspects of neuronal development, including axon guidance, neurite extension, and synapse formation and function. Recent research has highlighted the roles of LAR-RPTPs at neuronal synapses in mediating distinct synaptic adhesion pathways through interactions with a host of extracellular ligands and in governing a variety of intracellular signaling cascades through binding to various scaffolds and signaling proteins. In this chapter, we review and update current research progress on the extracellular ligands of LAR-RPTPs, regulation of their extracellular interactions by alternative splicing and heparan sulfates, and their intracellular signaling machineries. In particular, we review structural insights on complexes of LAR-RPTPs with their various ligands. These studies lend support to general molecular mechanisms underlying LAR-RPTP-mediated synaptic adhesion and signaling pathways.
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Affiliation(s)
- K A Han
- Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
| | - S Jeon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - J W Um
- Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
| | - J Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
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18
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Lai JKY, Doering LC, Foster JA. Developmental expression of the neuroligins and neurexins in fragile X mice. J Comp Neurol 2015; 524:807-28. [PMID: 26235839 DOI: 10.1002/cne.23868] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 07/20/2015] [Accepted: 07/21/2015] [Indexed: 11/08/2022]
Abstract
Neuroligins and neurexins are transsynaptic proteins involved in the maturation of glutamatergic and GABAergic synapses. Research has identified synaptic proteins and function as primary contributors to the development of fragile X syndrome. Fragile X mental retardation protein (FMRP), the protein that is lacking in fragile X syndrome, binds neuroligin-1 and -3 mRNA. Using in situ hybridization, we examined temporal and spatial expression patterns of neuroligin (NLGN) and neurexin (NRXN) mRNAs in the somatosensory (S1) cortex and hippocampus in wild-type (WT) and fragile X knockout (FMR1-KO) mice during the first 5 weeks of postnatal life. Genotype-based differences in expression included increased NLGN1 mRNA in CA1 and S1 cortex, decreased NLGN2 mRNA in CA1 and dentate gyrus (DG) regions of the hippocampus, and increased NRXN3 mRNA in CA1, DG, and S1 cortex between female WT and FMR1-KO mice. In male mice, decreased expression of NRXN3 mRNA was observed in CA1 and DG regions of FMR1-KO mice. Sex differences in hippocampal expression of NLGN2, NRXN1, NRXN2, and NRXN3 mRNAs and in S1 cortex expression of NRXN3 mRNAs were observed WT mice, whereas sex differences in NLGN3, NRXN1, NRXN2, and NRXN3 mRNA expression in the hippocampus and in NLGN1, NRXN2 and NRXN3 mRNA expression in S1 cortex were detected in FMR1-KO mice. These results provide a neuroanatomical map of NLGN and NRXN expression patterns over postnatal development in WT and FMR1-KO mice. The differences in developmental trajectory of these synaptic proteins could contribute to long-term differences in CNS wiring and synaptic function.
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Affiliation(s)
- Jonathan K Y Lai
- Department of Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, L8N 4L8, Canada.,Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, L8N 4A6, Canada
| | - Laurie C Doering
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, L8N 4L8, Canada
| | - Jane A Foster
- Department of Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, L8N 4L8, Canada.,Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, L8N 4A6, Canada
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19
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Choi SY, Han K, Cutforth T, Chung W, Park H, Lee D, Kim R, Kim MH, Choi Y, Shen K, Kim E. Mice lacking the synaptic adhesion molecule Neph2/Kirrel3 display moderate hyperactivity and defective novel object preference. Front Cell Neurosci 2015; 9:283. [PMID: 26283919 PMCID: PMC4517382 DOI: 10.3389/fncel.2015.00283] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/10/2015] [Indexed: 11/13/2022] Open
Abstract
Synaptic adhesion molecules regulate diverse aspects of neuronal synapse development, including synapse specificity, formation, and maturation. Neph2, also known as Kirrel3, is an immunoglobulin superfamily adhesion molecule implicated in intellectual disability, neurocognitive delay associated with Jacobsen syndrome, and autism spectrum disorders. We here report mice lacking Neph2 (Neph2(-/-) mice) display moderate hyperactivity in a familiar, but not novel, environment and defective novel object recognition with normal performances in Morris water maze spatial learning and memory, contextual fear conditioning and extinction, and pattern separation tests. These mice also show normal levels of anxiety-like behaviors, social interaction, and repetitive behaviors. At the synapse level, Neph2(-/-) dentate gyrus granule cells exhibit unaltered dendritic spine density and spontaneous excitatory synaptic transmission. These results suggest that Neph2 is important for normal locomotor activity and object recognition memory.
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Affiliation(s)
- Su-Yeon Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Kihoon Han
- Department of Neuroscience and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University Seoul, South Korea
| | - Tyler Cutforth
- Department of Neurology, Columbia University Medical Center New York, NY, USA
| | - Woosuk Chung
- Department of Biomedical Sciences, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Haram Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Dongsoo Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, South Korea
| | - Ryunhee Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Myeong-Heui Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Yeeun Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Kang Shen
- Department of Biology, Stanford University Stanford, CA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea ; Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, South Korea
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20
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Abstract
The function of neural circuits depends on the precise connectivity between populations of neurons. Increasing evidence indicates that disruptions in excitatory or inhibitory synapse formation or function lead to excitation/inhibition (E/I) imbalances and contribute to neurodevelopmental and psychiatric disorders. Leucine-rich repeat (LRR)-containing surface proteins have emerged as key organizers of excitatory and inhibitory synapses. Distinct LRR proteins are expressed in different cell types and interact with key pre- and postsynaptic proteins. These protein interaction networks allow LRR proteins to coordinate pre- and postsynaptic elements during synapse formation and differentiation, pathway-specific synapse development, and synaptic plasticity. LRR proteins, therefore, play a critical role in organizing synaptic connections into functional neural circuits, and their dysfunction may contribute to neuropsychiatric disorders.
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Affiliation(s)
- Joris de Wit
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium; KU Leuven, Center for Human Genetics, 3000 Leuven, Belgium.
| | - Anirvan Ghosh
- Neuroscience Discovery, F. Hoffman-La Roche, 4070 Basel, Switzerland
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21
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Fuchs C, Abitbol K, Burden JJ, Mercer A, Brown L, Iball J, Anne Stephenson F, Thomson AM, Jovanovic JN. GABA(A) receptors can initiate the formation of functional inhibitory GABAergic synapses. Eur J Neurosci 2013; 38:3146-58. [PMID: 23909897 PMCID: PMC4028986 DOI: 10.1111/ejn.12331] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 01/16/2023]
Abstract
The mechanisms that underlie the selection of an inhibitory GABAergic axon's postsynaptic targets and the formation of the first contacts are currently unknown. To determine whether expression of GABAA receptors (GABAA Rs) themselves--the essential functional postsynaptic components of GABAergic synapses--can be sufficient to initiate formation of synaptic contacts, a novel co-culture system was devised. In this system, the presynaptic GABAergic axons originated from embryonic rat basal ganglia medium spiny neurones, whereas their most prevalent postsynaptic targets, i.e., α1/β2/γ2-GABAA Rs, were expressed constitutively in a stably transfected human embryonic kidney 293 (HEK293) cell line. The first synapse-like contacts in these co-cultures were detected by colocalization of presynaptic and postsynaptic markers within 2 h. The number of contacts reached a plateau at 24 h. These contacts were stable, as assessed by live cell imaging; they were active, as determined by uptake of a fluorescently labelled synaptotagmin vesicle-luminal domain-specific antibody; and they supported spontaneous and action potential-driven postsynaptic GABAergic currents. Ultrastructural analysis confirmed the presence of characteristics typical of active synapses. Synapse formation was not observed with control or N-methyl-d-aspartate receptor-expressing HEK293 cells. A prominent increase in synapse formation and strength was observed when neuroligin-2 was co-expressed with GABAA Rs, suggesting a cooperative relationship between these proteins. Thus, in addition to fulfilling an essential functional role, postsynaptic GABAA Rs can promote the adhesion of inhibitory axons and the development of functional synapses.
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Affiliation(s)
- Celine Fuchs
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Karine Abitbol
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jemima J Burden
- MRC Laboratory of Molecular Cell Biology, University College LondonLondon, UK
| | - Audrey Mercer
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Laura Brown
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jonathan Iball
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - F Anne Stephenson
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Alex M Thomson
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
| | - Jasmina N Jovanovic
- UCL School of Pharmacy, University College London29–39 Brunswick Square, London, WC1N 1AX, UK
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22
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Abstract
Dramatic morphogenetic processes underpin nearly every step of nervous system development, from initial neuronal migration and axon guidance to synaptogenesis. Underlying this morphogenesis are dynamic rearrangements of cytoskeletal architecture. Here we discuss the roles of the actin cytoskeleton in the development of presynaptic terminals, from the elaboration of terminal arbors to the recruitment of presynaptic vesicles and active zone components. The studies discussed here underscore the importance of actin regulation at every step in neuronal circuit assembly.
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Affiliation(s)
- Jessica C Nelson
- Program in Cellular Neuroscience, Neurodegeneration and Repair; Department of Cell Biology; Yale University; New Haven, CT USA
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23
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Shan WS, Tanaka H, Phillips GR, Arndt K, Yoshida M, Colman DR, Shapiro L. Functional cis-heterodimers of N- and R-cadherins. J Cell Biol 2000; 148:579-90. [PMID: 10662782 PMCID: PMC2174798 DOI: 10.1083/jcb.148.3.579] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/1999] [Accepted: 12/24/1999] [Indexed: 12/03/2022] Open
Abstract
Classical cadherins form parallel cis-dimers that emanate from a single cell surface. It is thought that the cis-dimeric form is active in cell-cell adhesion, whereas cadherin monomers are likely to be inactive. Currently, cis-dimers have been shown to exist only between cadherins of the same type. Here, we show the specific formation of cis-heterodimers between N- and R-cadherins. E-cadherin cannot participate in these complexes. Cells coexpressing N- and R-cadherins show homophilic adhesion in which these proteins coassociate at cell-cell interfaces. We performed site- directed mutagenesis studies, the results of which support the strand dimer model for cis-dimerization. Furthermore, we show that when N- and R-cadherins are coexpressed in neurons in vitro, the two cadherins colocalize at certain neural synapses, implying biological relevance for these complexes. The present study provides a novel paradigm for cadherin interaction whereby selective cis-heterodimer formation may generate new functional units to mediate cell-cell adhesion.
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Affiliation(s)
- Wei-Song Shan
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - Hidekazu Tanaka
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - Greg R. Phillips
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - Kirsten Arndt
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - Mika Yoshida
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - David R. Colman
- Department of Biochemistry and Molecular Biology, Programs in Cell Adhesion and Structural Biology
| | - Lawrence Shapiro
- Department of Physiology and Biophysics, The Mount Sinai School of Medicine of New York University, New York, New York 10029
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