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Correa E, Mialon M, Cizeron M, Bessereau JL, Pinan-Lucarre B, Kratsios P. UNC-30/PITX coordinates neurotransmitter identity with postsynaptic GABA receptor clustering. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580278. [PMID: 38405977 PMCID: PMC10888783 DOI: 10.1101/2024.02.14.580278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Terminal selectors are transcription factors that control neuronal identity by regulating the expression of key effector molecules, such as neurotransmitter (NT) biosynthesis proteins, ion channels and neuropeptides. Whether and how terminal selectors control neuronal connectivity is poorly understood. Here, we report that UNC-30 (PITX2/3), the terminal selector of GABA motor neuron identity in C. elegans , is required for NT receptor clustering, a hallmark of postsynaptic differentiation. Animals lacking unc-30 or madd-4B, the short isoform of the MN-secreted synapse organizer madd-4 ( Punctin/ADAMTSL ), display severe GABA receptor type A (GABA A R) clustering defects in postsynaptic muscle cells. Mechanistically, UNC-30 acts directly to induce and maintain transcription of madd-4B and GABA biosynthesis genes (e.g., unc-25/GAD , unc-47/VGAT ). Hence, UNC-30 controls GABA A R clustering on postsynaptic muscle cells and GABA biosynthesis in presynaptic cells, transcriptionally coordinating two critical processes for GABA neurotransmission. Further, we uncover multiple target genes and a dual role for UNC-30 both as an activator and repressor of gene transcription. Our findings on UNC-30 function may contribute to our molecular understanding of human conditions, such as Axenfeld-Rieger syndrome, caused by PITX2 and PITX3 gene mutations.
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Florin F, Bonneau B, Briseño-Roa L, Bessereau JL, Jospin M. Calcineurin-Dependent Homeostatic Response of C. elegans Muscle Cells upon Prolonged Activation of Acetylcholine Receptors. Cells 2023; 12:2201. [PMID: 37681933 PMCID: PMC10486475 DOI: 10.3390/cells12172201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023] Open
Abstract
Pharmacological adaptation is a common phenomenon observed during prolonged drug exposure and often leads to drug resistance. Understanding the cellular events involved in adaptation could provide new strategies to circumvent this resistance issue. We used the nematode Caenorhabditis elegans to analyze the adaptation to levamisole, an ionotropic acetylcholine receptor agonist, used for decades to treat nematode parasitic infections. Genetic screens in C. elegans identified "adapting mutants" that initially paralyze upon exposure to levamisole as the wild type (WT), but recover locomotion after a few hours whereas WT remain paralyzed. Here, we show that levamisole induces a sustained increase in cytosolic calcium concentration in the muscle cells of adapting mutants, lasting several hours and preceding a decrease in levamisole-sensitive acetylcholine receptors (L-AChR) at the muscle plasma membrane. This decrease correlated with a drop in calcium concentration, a relaxation of the animal's body and a resumption of locomotion. The decrease in calcium and L-AChR content depends on calcineurin activation in muscle cells. We also showed that levamisole adaptation triggers homeostatic mechanisms in muscle cells including mitochondria remodeling, lysosomal tubulation and an increase in autophagic activity. Levamisole adaptation thus provides a new experimental paradigm for studying how cells cope with calcium stress.
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Affiliation(s)
- Franklin Florin
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
| | - Benjamin Bonneau
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
- Institut Curie, CNRS UMR3347, INSERM U1021, Université Paris-Saclay, F-91405 Orsay, France
| | - Luis Briseño-Roa
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
- Medetia Pharmaceuticals, Institut Imagine, F-75015 Paris, France
| | - Jean-Louis Bessereau
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
| | - Maëlle Jospin
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
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Nakayama M, Nishimura O, Nishimura Y, Kitaichi M, Kuraku S, Sone M, Hama C. Control of Synaptic Levels of Nicotinic Acetylcholine Receptor by the Sequestering Subunit Dα5 and Secreted Scaffold Protein Hig. J Neurosci 2023; 43:3989-4004. [PMID: 37117011 PMCID: PMC10255049 DOI: 10.1523/jneurosci.2243-21.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/30/2023] Open
Abstract
The presentation of nicotinic acetylcholine receptors (nAChRs) on synaptic membranes is crucial for generating cholinergic circuits, some of which are associated with memory function and neurodegenerative disorders. Although the physiology and structure of nAChR, a cation channel comprising five subunits, have been extensively studied, little is known about how the receptor levels in interneuronal synapses are determined and which nAChR subunits participate in the regulatory process in cooperation with synaptic cleft matrices and intracellular proteins. By a genetic screen of Drosophila, we identified mutations in the nAChR subunit Dα5 gene as suppressors that restored the mutant phenotypes of hig, which encodes a secretory matrix protein localized to cholinergic synaptic clefts in the brain. Only the loss of function of Dα5 among the 10 nAChR subunits suppressed hig mutant phenotypes in both male and female flies. Dα5 behaved as a lethal factor when Hig was defective; loss of Dα5 in hig mutants rescued lethality, upregulating Dα6 synaptic levels. By contrast, levels of Dα5, Dα6, and Dα7 subunits were all reduced in hig mutants. These three subunits have distinct properties for interaction with Hig or trafficking, as confirmed by chimeric subunit experiments. Notably, the chimeric Dα5 protein, which has the extracellular sequences that display no positive interaction with Hig, exhibited abnormal distribution and lethality even in the presence of Hig. We propose that the sequestering subunit Dα5 functions by reducing synaptic levels of nAChR through internalization, and this process is blocked by Hig, which tethers Dα5 to the synaptic cleft matrix.SIGNIFICANCE STATEMENT Because the cholinergic synapse is one of the major synapses that generate various brain functions, numerous studies have sought to reveal the physiology and structure of the nicotinic acetylcholine receptor (nAChR). However, little is known about how synaptic levels of nAChR are controlled and which nAChR subunits participate in the regulatory process in cooperation with synaptic cleft matrices. By a genetic screen of Drosophila, we identified mutations in the nAChR subunit Dα5 gene as suppressors that restored the mutant phenotypes of hig, which encodes a secretory matrix protein localized to cholinergic synaptic clefts. Our data indicate that Dα5 functions in reducing synaptic levels of nAChR, and this process is blocked by Hig, which tethers Dα5 to the synaptic cleft matrix.
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Affiliation(s)
- Minoru Nakayama
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
- Faculty of Science, Toho University, Funabashi 274-8510, Japan
| | - Osamu Nishimura
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, RIKEN, Kobe 650-0047, Japan
| | - Yuhi Nishimura
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Miwa Kitaichi
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Shigehiro Kuraku
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, RIKEN, Kobe 650-0047, Japan
| | - Masaki Sone
- Faculty of Science, Toho University, Funabashi 274-8510, Japan
| | - Chihiro Hama
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
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Laboy JT, Bonner J, Norman KR. DEC-7/SUSD2, a sushi domain-containing protein, regulates an ultradian behavior mediated by intestinal epithelial Ca 2+ oscillations in Caenorhabditis elegans. Am J Physiol Cell Physiol 2023; 324:C1158-C1170. [PMID: 37067458 PMCID: PMC10191124 DOI: 10.1152/ajpcell.00552.2022] [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: 12/13/2022] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
In Caenorhabditis elegans, rhythmic posterior body wall muscle contractions mediate the highly regular defecation cycle. These contractions are regulated by inositol-1,4,5-trisphosphate (InsP3) receptor-dependent Ca2+ oscillations in intestinal epithelial cells. Here, we find that mutations in dec-7, which encodes the nematode ortholog of the human Sushi domain-containing 2 protein (SUSD2), lead to an increase in InsP3 receptor-dependent rhythmic posterior body wall muscle contractions. DEC-7 is highly expressed in the intestinal epithelia and localizes to the cell-cell junction. The increase in rhythmic activity caused by the loss of dec-7 is dependent on the innexin gap junction protein INX-16. Moreover, DEC-7 is required for the clustering of INX-16 to the cell-cell junction of the intestinal epithelia. We hypothesize that DEC-7/SUSD2 regulates INX-16 activity to mediate the rhythmic frequency of the defecation motor program. Thus, our data indicate a critical role of a phylogenetically conserved cell-cell junction protein in mediating an ultradian rhythm in the intestinal epithelia of C. elegans.NEW & NOTEWORTHY The conserved complement group protein DEC-7/SUSD2 acts at the apical cell-cell junction of C. elegans intestinal epithelia to mediate gap junction protein organization and function to facilitate a Ca2+ wave-regulated ultradian behavior.
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Affiliation(s)
- Jocelyn T Laboy
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York, United States
| | - Jennifer Bonner
- Department of Biology, Skidmore College, Saratoga Springs, New York, United States
| | - Kenneth R Norman
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York, United States
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Cell context-dependent CFI-1/ARID3 functions control neuronal terminal differentiation. Cell Rep 2023; 42:112220. [PMID: 36897776 PMCID: PMC10124151 DOI: 10.1016/j.celrep.2023.112220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 12/21/2022] [Accepted: 02/20/2023] [Indexed: 03/11/2023] Open
Abstract
AT-rich interaction domain 3 (ARID3) transcription factors are expressed in the nervous system, but their mechanisms of action are largely unknown. Here, we provide, in vivo, a genome-wide binding map for CFI-1, the sole C. elegans ARID3 ortholog. We identify 6,396 protein-coding genes as putative direct targets of CFI-1, most of which encode neuronal terminal differentiation markers. In head sensory neurons, CFI-1 directly activates multiple terminal differentiation genes, thereby acting as a terminal selector. In motor neurons, however, CFI-1 acts as a direct repressor, continuously antagonizing three transcriptional activators. By focusing on the glr-4/GRIK4 glutamate receptor locus, we identify proximal CFI-1 binding sites and histone methyltransferase activity as necessary for glr-4 repression. Rescue assays reveal functional redundancy between core and extended DNA-binding ARID domains and a strict requirement for REKLES, the ARID3 oligomerization domain. Altogether, this study uncovers cell-context-dependent mechanisms through which a single ARID3 protein controls the terminal differentiation of distinct neuron types.
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Mizumoto K, Jin Y, Bessereau JL. Synaptogenesis: unmasking molecular mechanisms using Caenorhabditis elegans. Genetics 2023; 223:iyac176. [PMID: 36630525 PMCID: PMC9910414 DOI: 10.1093/genetics/iyac176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/22/2022] [Indexed: 01/13/2023] Open
Abstract
The nematode Caenorhabditis elegans is a research model organism particularly suited to the mechanistic understanding of synapse genesis in the nervous system. Armed with powerful genetics, knowledge of complete connectomics, and modern genomics, studies using C. elegans have unveiled multiple key regulators in the formation of a functional synapse. Importantly, many signaling networks display remarkable conservation throughout animals, underscoring the contributions of C. elegans research to advance the understanding of our brain. In this chapter, we will review up-to-date information of the contribution of C. elegans to the understanding of chemical synapses, from structure to molecules and to synaptic remodeling.
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Affiliation(s)
- Kota Mizumoto
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z3, Canada
| | - Yishi Jin
- Department of Neurobiology, University of California San Diego, La Jolla, CA 92093, USA
| | - Jean-Louis Bessereau
- Univ Lyon, University Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U 1314, Melis, 69008 Lyon, France
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7
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Izquierdo PG, Charvet CL, Neveu C, Green AC, Tattersall JEH, Holden-Dye L, O'Connor V. Modelling organophosphate intoxication in C. elegans highlights nicotinic acetylcholine receptor determinants that mitigate poisoning. PLoS One 2023; 18:e0284786. [PMID: 37083685 PMCID: PMC10121051 DOI: 10.1371/journal.pone.0284786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 04/06/2023] [Indexed: 04/22/2023] Open
Abstract
Organophosphate intoxication via acetylcholinesterase inhibition executes neurotoxicity via hyper stimulation of acetylcholine receptors. Here, we use the organophosphate paraoxon-ethyl to treat C. elegans and use its impact on pharyngeal pumping as a bio-assay to model poisoning through these neurotoxins. This assay provides a tractable measure of acetylcholine receptor mediated contraction of body wall muscle. Investigation of the time dependence of organophosphate treatment and the genetic determinants of the drug-induced inhibition of pumping highlight mitigating modulation of the effects of paraoxon-ethyl. We identified mutants that reduce acetylcholine receptor function protect against the consequence of intoxication by organophosphates. Data suggests that reorganization of cholinergic signalling is associated with organophosphate poisoning. This reinforces the under investigated potential of using therapeutic approaches which target a modulation of nicotinic acetylcholine receptor function to treat the poisoning effects of this important class of neurotoxins.
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Affiliation(s)
- Patricia G Izquierdo
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Claude L Charvet
- French National Institute for Agricultural Research (INRA), Infectiologie Animale et Santé Publique, Nouzilly, France
| | - Cedric Neveu
- French National Institute for Agricultural Research (INRA), Infectiologie Animale et Santé Publique, Nouzilly, France
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Vincent O'Connor
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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An extracellular scaffolding complex confers unusual rectification upon an ionotropic acetylcholine receptor in C. elegans. Proc Natl Acad Sci U S A 2022; 119:e2113545119. [PMID: 35858330 PMCID: PMC9304021 DOI: 10.1073/pnas.2113545119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Biophysical properties of ligand-gated receptors can be profoundly modified by auxiliary subunits or by the lipid microenvironment of the membrane. Hence, it is sometimes challenging to relate the properties of receptors reconstituted in heterologous expression systems to those of their native counterparts. Here we show that the properties of Caenorhabditis elegans levamisole-sensitive acetylcholine receptors (L-AChRs), the ionotropic acetylcholine receptors targeted by the cholinergic anthelmintic levamisole at neuromuscular junctions, can be profoundly modified by their clustering machinery. We uncovered that L-AChRs exhibit a strong outward rectification in vivo, which was not previously described in heterologous systems. This unusual feature for an ionotropic AChR is abolished by disrupting the interaction of the receptors with the extracellular complex required for their synaptic clustering. When recorded at -60 mV, levamisole-induced currents are similar in the wild type and in L-AChR-clustering-defective mutants, while they are halved in these mutants at more depolarized physiological membrane potentials. Consequently, levamisole causes a strong muscle depolarization in the wild type, which leads to complete inactivation of the voltage-gated calcium channels and to an irreversible flaccid paralysis. In mutants defective for L-AChR clustering, the levamisole-induced depolarization is weaker, allowing voltage-gated calcium channels to remain partially active, which eventually leads to adaptation and survival of the worms. This explains why historical screens for C. elegans mutants resistant to levamisole identified the components of the L-AChR clustering machinery, in addition to proteins required for receptor biosynthesis or efficacy. This work further emphasizes the importance of pursuing ligand-gated channel characterization in their native environment.
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Paredes GF, Viehboeck T, Markert S, Mausz MA, Sato Y, Liebeke M, König L, Bulgheresi S. Differential regulation of degradation and immune pathways underlies adaptation of the ectosymbiotic nematode Laxus oneistus to oxic-anoxic interfaces. Sci Rep 2022; 12:9725. [PMID: 35697683 PMCID: PMC9192688 DOI: 10.1038/s41598-022-13235-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 05/13/2022] [Indexed: 11/09/2022] Open
Abstract
Eukaryotes may experience oxygen deprivation under both physiological and pathological conditions. Because oxygen shortage leads to a reduction in cellular energy production, all eukaryotes studied so far conserve energy by suppressing their metabolism. However, the molecular physiology of animals that naturally and repeatedly experience anoxia is underexplored. One such animal is the marine nematode Laxus oneistus. It thrives, invariably coated by its sulfur-oxidizing symbiont Candidatus Thiosymbion oneisti, in anoxic sulfidic or hypoxic sand. Here, transcriptomics and proteomics showed that, whether in anoxia or not, L. oneistus mostly expressed genes involved in ubiquitination, energy generation, oxidative stress response, immune response, development, and translation. Importantly, ubiquitination genes were also highly expressed when the nematode was subjected to anoxic sulfidic conditions, together with genes involved in autophagy, detoxification and ribosome biogenesis. We hypothesize that these degradation pathways were induced to recycle damaged cellular components (mitochondria) and misfolded proteins into nutrients. Remarkably, when L. oneistus was subjected to anoxic sulfidic conditions, lectin and mucin genes were also upregulated, potentially to promote the attachment of its thiotrophic symbiont. Furthermore, the nematode appeared to survive oxygen deprivation by using an alternative electron carrier (rhodoquinone) and acceptor (fumarate), to rewire the electron transfer chain. On the other hand, under hypoxia, genes involved in costly processes (e.g., amino acid biosynthesis, development, feeding, mating) were upregulated, together with the worm's Toll-like innate immunity pathway and several immune effectors (e.g., bactericidal/permeability-increasing proteins, fungicides). In conclusion, we hypothesize that, in anoxic sulfidic sand, L. oneistus upregulates degradation processes, rewires the oxidative phosphorylation and reinforces its coat of bacterial sulfur-oxidizers. In upper sand layers, instead, it appears to produce broad-range antimicrobials and to exploit oxygen for biosynthesis and development.
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Affiliation(s)
- Gabriela F Paredes
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria
| | - Tobias Viehboeck
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria
- Vienna Doctoral School of Ecology and Evolution, Vienna, Austria
- Division of Microbial Ecology, Center for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Stephanie Markert
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | | | - Yui Sato
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Manuel Liebeke
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Lena König
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria
| | - Silvia Bulgheresi
- Department of Functional and Evolutionary Ecology, Environmental Cell Biology Group, University of Vienna, Vienna, Austria.
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10
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The signaling pathway of levamisole-sensitive-acetylcholine receptors involved in short-term forgetting of Caenorhabditis elegans. Mol Genet Genomics 2022; 297:1027-1038. [PMID: 35585325 DOI: 10.1007/s00438-022-01901-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/16/2022] [Indexed: 10/18/2022]
Abstract
In contrast to the popular opinion that forgetting is only the opposite of learning and memory, active forgetting explains the intrinsic instability of a labile memory that lasts for hours and has its own signal transduction pathways. However, the detailed mechanisms underlying forgetting are still lacking, though the investigations available in this field offer the first insights into their regulation. To identify the alternative signaling pathways that control the process of forgetting, we used the short-term forgetting model of Caenorhabditis elegans and discovered the involvement of lev-10, a scaffolded transmembrane protein of L-AChR, by screening the candidate genes that potentially functioned in synaptic plasticity. The LEV-9/LEV-10/L-AChR functional complex was confirmed to participate in forgetting occurrence. Furthermore, EGL-9 functioned upstream of LEV-10 and negatively regulated the latter during forgetting. Meanwhile, EGL-9 was also the target of miR-51, and hence the mutation of miR-51 similarly affected the function of L-AChR and delayed the short-term forgetting. Our findings have identified an integrated signaling pathway responsible for active forgetting, which provides the new experimental evidence on the cholinergic forgetting signal.
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11
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González-Calvo I, Cizeron M, Bessereau JL, Selimi F. Synapse Formation and Function Across Species: Ancient Roles for CCP, CUB, and TSP-1 Structural Domains. Front Neurosci 2022; 16:866444. [PMID: 35546877 PMCID: PMC9083331 DOI: 10.3389/fnins.2022.866444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/28/2022] [Indexed: 11/17/2022] Open
Abstract
The appearance of synapses was a crucial step in the creation of the variety of nervous systems that are found in the animal kingdom. With increased complexity of the organisms came a greater number of synaptic proteins. In this review we describe synaptic proteins that contain the structural domains CUB, CCP, or TSP-1. These domains are found in invertebrates and vertebrates, and CUB and CCP domains were initially described in proteins belonging to the complement system of innate immunity. Interestingly, they are found in synapses of the nematode C. elegans, which does not have a complement system, suggesting an ancient function. Comparison of the roles of CUB-, CCP-, and TSP-1 containing synaptic proteins in various species shows that in more complex nervous systems, these structural domains are combined with other domains and that there is partial conservation of their function. These three domains are thus basic building blocks of the synaptic architecture. Further studies of structural domains characteristic of synaptic proteins in invertebrates such as C. elegans and comparison of their role in mammals will help identify other conserved synaptic molecular building blocks. Furthermore, this type of functional comparison across species will also identify structural domains added during evolution in correlation with increased complexity, shedding light on mechanisms underlying cognition and brain diseases.
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Affiliation(s)
- Inés González-Calvo
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Mélissa Cizeron
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5284, INSERM U-1314, MeLiS, Institut NeuroMyoGène, Lyon, France
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5284, INSERM U-1314, MeLiS, Institut NeuroMyoGène, Lyon, France
| | - Fekrije Selimi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
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12
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Izquierdo PG, Calahorro F, Thisainathan T, Atkins JH, Haszczyn J, Lewis CJ, Tattersall JEH, Green AC, Holden-Dye L, O'Connor V. Cholinergic signaling at the body wall neuromuscular junction distally inhibits feeding behavior in Caenorhabditis elegans. J Biol Chem 2021; 298:101466. [PMID: 34864060 PMCID: PMC8801469 DOI: 10.1016/j.jbc.2021.101466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 12/27/2022] Open
Abstract
Complex biological functions within organisms are frequently orchestrated by systemic communication between tissues. In the model organism Caenorhabditis elegans, the pharyngeal and body wall neuromuscular junctions are two discrete structures that control feeding and locomotion, respectively. Separate, the well-defined neuromuscular circuits control these distinct tissues. Nonetheless, the emergent behaviors, feeding and locomotion, are coordinated to guarantee the efficiency of food intake. Here, we show that pharmacological hyperactivation of cholinergic transmission at the body wall muscle reduces the rate of pumping behavior. This was evidenced by a systematic screening of the effect of the cholinesterase inhibitor aldicarb on the rate of pharyngeal pumping on food in mutant worms. The screening revealed that the key determinants of the inhibitory effect of aldicarb on pharyngeal pumping are located at the body wall neuromuscular junction. In fact, the selective stimulation of the body wall muscle receptors with the agonist levamisole inhibited pumping in a lev-1-dependent fashion. Interestingly, this response was independent of unc-38, an alpha subunit of the nicotinic receptor classically expressed with lev-1 at the body wall muscle. This implies an uncharacterized lev-1-containing receptor underpins this effect. Overall, our results reveal that body wall cholinergic transmission not only controls locomotion but simultaneously inhibits feeding behavior.
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Affiliation(s)
- Patricia G Izquierdo
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Fernando Calahorro
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Thibana Thisainathan
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - James H Atkins
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Johanna Haszczyn
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Christian J Lewis
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
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13
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Sonobe Y, Aburas J, Krishnan G, Fleming AC, Ghadge G, Islam P, Warren EC, Gu Y, Kankel MW, Brown AEX, Kiskinis E, Gendron TF, Gao FB, Roos RP, Kratsios P. A C. elegans model of C9orf72-associated ALS/FTD uncovers a conserved role for eIF2D in RAN translation. Nat Commun 2021; 12:6025. [PMID: 34654821 PMCID: PMC8519953 DOI: 10.1038/s41467-021-26303-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/28/2021] [Indexed: 12/31/2022] Open
Abstract
A hexanucleotide repeat expansion GGGGCC in the non-coding region of C9orf72 is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Toxic dipeptide repeats (DPRs) are synthesized from GGGGCC via repeat-associated non-AUG (RAN) translation. Here, we develop C. elegans models that express, either ubiquitously or exclusively in neurons, 75 GGGGCC repeats flanked by intronic C9orf72 sequence. The worms generate DPRs (poly-glycine-alanine [poly-GA], poly-glycine-proline [poly-GP]) and poly-glycine-arginine [poly-GR]), display neurodegeneration, and exhibit locomotor and lifespan defects. Mutation of a non-canonical translation-initiating codon (CUG) upstream of the repeats selectively reduces poly-GA steady-state levels and ameliorates disease, suggesting poly-GA is pathogenic. Importantly, loss-of-function mutations in the eukaryotic translation initiation factor 2D (eif-2D/eIF2D) reduce poly-GA and poly-GP levels, and increase lifespan in both C. elegans models. Our in vitro studies in mammalian cells yield similar results. Here, we show a conserved role for eif-2D/eIF2D in DPR expression.
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Affiliation(s)
- Yoshifumi Sonobe
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Jihad Aburas
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA ,grid.170205.10000 0004 1936 7822Department of Neurobiology, University of Chicago, Chicago, IL USA
| | - Gopinath Krishnan
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Andrew C. Fleming
- grid.16753.360000 0001 2299 3507The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Ghanashyam Ghadge
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Priota Islam
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Eleanor C. Warren
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Yuanzheng Gu
- grid.417832.b0000 0004 0384 8146Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142 USA
| | - Mark W. Kankel
- grid.417832.b0000 0004 0384 8146Neuromuscular & Movement Disorders, Biogen, Cambridge, MA 02142 USA
| | - André E. X. Brown
- grid.14105.310000000122478951MRC London Institute of Medical Sciences, London, UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences, Imperial College London, London, UK
| | - Evangelos Kiskinis
- grid.16753.360000 0001 2299 3507The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Tania F. Gendron
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Fen-Biao Gao
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Raymond P. Roos
- grid.412578.d0000 0000 8736 9513University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.412578.d0000 0000 8736 9513Department of Neurology, University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL USA
| | - Paschalis Kratsios
- University of Chicago Medical Center, 5841S. Maryland Avenue, Chicago, IL, 60637, USA. .,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, IL, USA. .,Department of Neurobiology, University of Chicago, Chicago, IL, USA.
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14
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Nash A, Aumann TD, Pigoni M, Lichtenthaler SF, Takeshima H, Munro KM, Gunnersen JM. Lack of Sez6 Family Proteins Impairs Motor Functions, Short-Term Memory, and Cognitive Flexibility and Alters Dendritic Spine Properties. Cereb Cortex 2021; 30:2167-2184. [PMID: 31711114 DOI: 10.1093/cercor/bhz230] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/22/2019] [Accepted: 09/02/2019] [Indexed: 02/05/2023] Open
Abstract
Seizure-related gene 6 (Sez6), Sez6-Like (Sez6L), and Sez6-Like 2 (Sez6L2) comprise a family of homologous proteins widely expressed throughout the brain that have been linked to neurodevelopmental and psychiatric disorders. Here, we use Sez6 triple knockout (TKO) mice, which lack all three Sez6 family proteins, to demonstrate that Sez6 family proteins regulate dendritic spine structure and cognitive functions, motor learning, and maintenance of motor functions across the lifespan. Compared to WT controls, we found that Sez6 TKO mice had impaired motor learning and their motor coordination was negatively affected from 6 weeks old and declined more rapidly as they aged. Sez6 TKO mice had reduced spine density in the hippocampus and dendritic spines were shifted to more immature morphologies in the somatosensory cortex. Cognitive testing revealed that they had enhanced stress responsiveness, impaired working, and spatial short-term memory but intact spatial long-term memory in the Morris water maze albeit accompanied by a reversal deficit. Our study demonstrates that the lack of Sez6 family proteins results in phenotypes commonly associated with neuropsychiatric disorders making it likely that Sez6 family proteins contribute to the complex etiologies of these disorders.
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Affiliation(s)
- Amelia Nash
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Timothy D Aumann
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Martina Pigoni
- German Centre for Neurodegenerative Diseases (DZNE), Munich 81377, Germany
| | - Stefan F Lichtenthaler
- German Centre for Neurodegenerative Diseases (DZNE), Munich 81377, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, and Institute for Advanced Study, Technical University of Munich, Munich 81675, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich 81377, Germany
| | - Hiroshi Takeshima
- Division of Pharmaceutical Sciences, Graduate School and Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Kathryn M Munro
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jenny M Gunnersen
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC 3010, Australia.,The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
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15
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Rapti G. A perspective on C. elegans neurodevelopment: from early visionaries to a booming neuroscience research. J Neurogenet 2021; 34:259-272. [PMID: 33446023 DOI: 10.1080/01677063.2020.1837799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The formation of the nervous system and its striking complexity is a remarkable feat of development. C. elegans served as a unique model to dissect the molecular events in neurodevelopment, from its early visionaries to the current booming neuroscience community. Soon after being introduced as a model, C. elegans was mapped at the level of genes, cells, and synapses, providing the first metazoan with a complete cell lineage, sequenced genome, and connectome. Here, I summarize mechanisms underlying C. elegans neurodevelopment, from the generation and diversification of neural components to their navigation and connectivity. I point out recent noteworthy findings in the fields of glia biology, sex dimorphism and plasticity in neurodevelopment, highlighting how current research connects back to the pioneering studies by Brenner, Sulston and colleagues. Multifaceted investigations in model organisms, connecting genes to cell function and behavior, expand our mechanistic understanding of neurodevelopment while allowing us to formulate emerging questions for future discoveries.
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Affiliation(s)
- Georgia Rapti
- European Molecular Biology Laboratory, Unit of Developmental Biology, Heidelberg, Germany
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16
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Zhou X, Vachon C, Cizeron M, Romatif O, Bülow HE, Jospin M, Bessereau JL. The HSPG syndecan is a core organizer of cholinergic synapses. J Cell Biol 2021; 220:212450. [PMID: 34213535 PMCID: PMC8258370 DOI: 10.1083/jcb.202011144] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 04/13/2021] [Accepted: 05/26/2021] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix has emerged as an active component of chemical synapses regulating synaptic formation, maintenance, and homeostasis. The heparan sulfate proteoglycan (HSPG) syndecans are known to regulate cellular and axonal migration in the brain. They are also enriched at synapses, but their synaptic functions remain more elusive. Here, we show that SDN-1, the sole orthologue of syndecan in C. elegans, is absolutely required for the synaptic clustering of homomeric α7-like acetylcholine receptors (AChRs) and regulates the synaptic content of heteromeric AChRs. SDN-1 is concentrated at neuromuscular junctions (NMJs) by the neurally secreted synaptic organizer Ce-Punctin/MADD-4, which also activates the transmembrane netrin receptor DCC. Those cooperatively recruit the FARP and CASK orthologues that localize α7-like-AChRs at cholinergic NMJs through physical interactions. Therefore, SDN-1 stands at the core of the cholinergic synapse organization by bridging the extracellular synaptic determinants to the intracellular synaptic scaffold that controls the postsynaptic receptor content.
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Affiliation(s)
- Xin Zhou
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Camille Vachon
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Mélissa Cizeron
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Océane Romatif
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Hannes E Bülow
- Department of Genetics and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY
| | - Maëlle Jospin
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Jean-Louis Bessereau
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
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17
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Cizeron M, Granger L, Bülow HE, Bessereau JL. Specific heparan sulfate modifications stabilize the synaptic organizer MADD-4/Punctin at C. elegans neuromuscular junctions. Genetics 2021; 218:6275221. [PMID: 33983408 DOI: 10.1093/genetics/iyab073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023] Open
Abstract
Heparan sulfate proteoglycans contribute to the structural organization of various neurochemical synapses. Depending on the system, their role involves either the core protein or the glycosaminoglycan chains. These linear sugar chains are extensively modified by heparan sulfate modification enzymes, resulting in highly diverse molecules. Specific modifications of glycosaminoglycan chains may thus contribute to a sugar code involved in synapse specificity. Caenorhabditis elegans is particularly useful to address this question because of the low level of genomic redundancy of these enzymes, as opposed to mammals. Here, we systematically mutated the genes encoding heparan sulfate modification enzymes in C. elegans and analyzed their impact on excitatory and inhibitory neuromuscular junctions. Using single chain antibodies that recognize different heparan sulfate modification patterns, we show in vivo that these two heparan sulfate epitopes are carried by the SDN-1 core protein, the unique C. elegans syndecan orthologue, at neuromuscular junctions. Intriguingly, these antibodies differentially bind to excitatory and inhibitory synapses, implying unique heparan sulfate modification patterns at different neuromuscular junctions. Moreover, while most enzymes are individually dispensable for proper organization of neuromuscular junctions, we show that 3-O-sulfation of SDN-1 is required to maintain wild-type levels of the extracellular matrix protein MADD-4/Punctin, a central synaptic organizer that defines the identity of excitatory and inhibitory synaptic domains at the plasma membrane of muscle cells.
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Affiliation(s)
- Mélissa Cizeron
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, 69008 Lyon, France
| | - Laure Granger
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, 69008 Lyon, France
| | - Hannes E Bülow
- Department of Genetics & Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, 69008 Lyon, France
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18
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A complement factor H homolog, heparan sulfation, and syndecan maintain inversin compartment boundaries in C. elegans cilia. Proc Natl Acad Sci U S A 2021; 118:2016698118. [PMID: 33859044 DOI: 10.1073/pnas.2016698118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly. Canonical disease models suggest that defective interactions between complement factor H (CFH) and cell surface heparan sulfate (HS) result in increased alternative complement pathway activity, cytolytic damage, and tissue inflammation in the retina. Although these factors are thought to contribute to increased disease risk, multiple studies indicate that noncanonical mechanisms that result from defective CFH and HS interaction may contribute to the progression of AMD as well. A total of 60 ciliated sensory neurons in the nematode Caenorhabditis elegans detect chemical, olfactory, mechanical, and thermal cues in the environment. Here, we find that a C. elegans CFH homolog localizes on CEP mechanosensory neuron cilia where it has noncanonical roles in maintaining inversin/NPHP-2 within its namesake proximal compartment and preventing inversin/NPHP-2 accumulation in distal cilia compartments in aging adults. CFH localization and maintenance of inversin/NPHP-2 compartment integrity depend on the HS 3-O sulfotransferase HST-3.1 and the transmembrane proteoglycan syndecan/SDN-1. Defective inversin/NPHP-2 localization in mouse and human photoreceptors with CFH mutations indicates that these functions and interactions may be conserved in vertebrate sensory neurons, suggesting that previously unappreciated defects in cilia structure may contribute to the progressive photoreceptor dysfunction associated with CFH loss-of-function mutations in some AMD patients.
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19
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Chaya T, Patel S, Smith EM, Lam A, Miller EN, Clupper M, Kervin K, Tanis JE. A C. elegans genome-wide RNAi screen for altered levamisole sensitivity identifies genes required for muscle function. G3-GENES GENOMES GENETICS 2021; 11:6169532. [PMID: 33713125 PMCID: PMC8049432 DOI: 10.1093/g3journal/jkab047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/09/2021] [Indexed: 01/17/2023]
Abstract
At the neuromuscular junction (NMJ), postsynaptic ionotropic acetylcholine receptors (AChRs) transduce a chemical signal released from a cholinergic motor neuron into an electrical signal to induce muscle contraction. To identify regulators of postsynaptic function, we conducted a genome-wide RNAi screen for genes required for proper response to levamisole, a pharmacological agonist of ionotropic L-AChRs at the Caenorhabditis elegans NMJ. A total of 117 gene knockdowns were found to cause levamisole hypersensitivity, while 18 resulted in levamisole resistance. Our screen identified conserved genes important for muscle function including some that are mutated in congenital myasthenic syndrome, congenital muscular dystrophy, congenital myopathy, myotonic dystrophy, and mitochondrial myopathy. Of the genes found in the screen, we further investigated those predicted to play a role in endocytosis of cell surface receptors. Loss of the Epsin homolog epn-1 caused levamisole hypersensitivity and had opposing effects on the levels of postsynaptic L-AChRs and GABAA receptors, resulting in increased and decreased abundance, respectively. We also examined other genes that resulted in a levamisole-hypersensitive phenotype when knocked down including gas-1, which functions in Complex I of the mitochondrial electron transport chain. Consistent with altered ATP synthesis impacting levamisole response, treatment of wild-type animals with levamisole resulted in L-AChR–dependent depletion of ATP levels. These results suggest that the paralytic effects of levamisole ultimately lead to metabolic exhaustion.
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Affiliation(s)
- Timothy Chaya
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shrey Patel
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Erin M Smith
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Andy Lam
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Elaine N Miller
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Michael Clupper
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Kirsten Kervin
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jessica E Tanis
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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20
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González-Calvo I, Iyer K, Carquin M, Khayachi A, Giuliani FA, Sigoillot SM, Vincent J, Séveno M, Veleanu M, Tahraoui S, Albert M, Vigy O, Bosso-Lefèvre C, Nadjar Y, Dumoulin A, Triller A, Bessereau JL, Rondi-Reig L, Isope P, Selimi F. Sushi domain-containing protein 4 controls synaptic plasticity and motor learning. eLife 2021; 10:65712. [PMID: 33661101 PMCID: PMC7972451 DOI: 10.7554/elife.65712] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/03/2021] [Indexed: 01/28/2023] Open
Abstract
Fine control of protein stoichiometry at synapses underlies brain function and plasticity. How proteostasis is controlled independently for each type of synaptic protein in a synapse-specific and activity-dependent manner remains unclear. Here, we show that Susd4, a gene coding for a complement-related transmembrane protein, is expressed by many neuronal populations starting at the time of synapse formation. Constitutive loss-of-function of Susd4 in the mouse impairs motor coordination adaptation and learning, prevents long-term depression at cerebellar synapses, and leads to misregulation of activity-dependent AMPA receptor subunit GluA2 degradation. We identified several proteins with known roles in the regulation of AMPA receptor turnover, in particular ubiquitin ligases of the NEDD4 subfamily, as SUSD4 binding partners. Our findings shed light on the potential role of SUSD4 mutations in neurodevelopmental diseases.
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Affiliation(s)
- Inés González-Calvo
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France.,Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS, Université de Strasbourg, Strasbourg, France
| | - Keerthana Iyer
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Mélanie Carquin
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Anouar Khayachi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Fernando A Giuliani
- Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS, Université de Strasbourg, Strasbourg, France
| | - Séverine M Sigoillot
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Jean Vincent
- Institut Biology Paris Seine (IBPS), Neuroscience Paris Seine (NPS), CeZaMe, CNRS, Sorbonne University, INSERM, Paris, France
| | - Martial Séveno
- BioCampus Montpellier, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Maxime Veleanu
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Sylvana Tahraoui
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Mélanie Albert
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Oana Vigy
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Célia Bosso-Lefèvre
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Yann Nadjar
- École Normale Supérieure, Institut de Biologie de l'ENS, INSERM, CNRS, PSL Research University, Paris, France
| | - Andréa Dumoulin
- École Normale Supérieure, Institut de Biologie de l'ENS, INSERM, CNRS, PSL Research University, Paris, France
| | - Antoine Triller
- École Normale Supérieure, Institut de Biologie de l'ENS, INSERM, CNRS, PSL Research University, Paris, France
| | - Jean-Louis Bessereau
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut Neuromyogène, Lyon, France
| | - Laure Rondi-Reig
- Institut Biology Paris Seine (IBPS), Neuroscience Paris Seine (NPS), CeZaMe, CNRS, Sorbonne University, INSERM, Paris, France
| | - Philippe Isope
- Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS, Université de Strasbourg, Strasbourg, France
| | - Fekrije Selimi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
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21
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Fossati M, Charrier C. Trans-synaptic interactions of ionotropic glutamate receptors. Curr Opin Neurobiol 2020; 66:85-92. [PMID: 33130410 DOI: 10.1016/j.conb.2020.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/01/2020] [Accepted: 09/01/2020] [Indexed: 01/29/2023]
Abstract
Trans-synaptic interactions organize the multiple steps of synaptic development and are critical to generate fully functional neuronal circuits. While trans-synaptic interactions are primarily mediated by cell adhesion molecules (CAMs), some directly involve ionotropic glutamate receptors (iGluRs). Here, we review the expanding extracellular and trans-synaptic proteome of iGluRs. We discuss the role of these molecular networks in specifying the formation of excitatory and inhibitory circuits and in the input-specific recruitment of iGluRs at synapses in various cell types and brain regions. We also shed light on human-specific mutations affecting iGluR-mediated trans-synaptic interactions that may provide unique features to the human brain and contribute to its susceptibility to neurodevelopmental disorders. Together, these data support a view in which iGluR function goes far beyond fast excitatory synaptic transmission by shaping the wiring and the functional properties of neural circuits.
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Affiliation(s)
- Matteo Fossati
- CNR - Institute of Neuroscience, via Manzoni 56, Rozzano (MI), 20089, Italy; Humanitas Clinical and Research Center - IRCCS, via Manzoni 56, Rozzano (MI), 20089, Italy.
| | - Cécile Charrier
- Institut de Biologie de l'École Normale Supérieure (IBENS), CNRS, Inserm, École Normale Supérieure, PSL Research University, Paris, 75005, France.
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22
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Treinin M, Jin Y. Cholinergic transmission in C. elegans: Functions, diversity, and maturation of ACh-activated ion channels. J Neurochem 2020; 158:1274-1291. [PMID: 32869293 DOI: 10.1111/jnc.15164] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023]
Abstract
Acetylcholine is an abundant neurotransmitter in all animals. Effects of acetylcholine are excitatory, inhibitory, or modulatory depending on the receptor and cell type. Research using the nematode C. elegans has made ground-breaking contributions to the mechanistic understanding of cholinergic transmission. Powerful genetic screens for behavioral mutants or for responses to pharmacological reagents identified the core cellular machinery for synaptic transmission. Pharmacological reagents that perturb acetylcholine-mediated processes led to the discovery and also uncovered the composition and regulators of acetylcholine-activated channels and receptors. From a combination of electrophysiological and molecular cellular studies, we have gained a profound understanding of cholinergic signaling at the levels of synapses, neural circuits, and animal behaviors. This review will begin with a historical overview, then cover in-depth current knowledge on acetylcholine-activated ionotropic receptors, mechanisms regulating their functional expression and their functions in regulating locomotion.
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Affiliation(s)
- Millet Treinin
- Department of Medical Neurobiology, Hadassah Medical school - Hebrew University, Jerusalem, Israel
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
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23
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Pigoni M, Hsia H, Hartmann J, Rudan Njavro J, Shmueli MD, Müller SA, Güner G, Tüshaus J, Kuhn P, Kumar R, Gao P, Tran ML, Ramazanov B, Blank B, Hipgrave Ederveen AL, Von Blume J, Mulle C, Gunnersen JM, Wuhrer M, Rammes G, Busche MA, Koeglsperger T, Lichtenthaler SF. Seizure protein 6 controls glycosylation and trafficking of kainate receptor subunits GluK2 and GluK3. EMBO J 2020; 39:e103457. [PMID: 32567721 PMCID: PMC7396870 DOI: 10.15252/embj.2019103457] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 12/19/2022] Open
Abstract
Seizure protein 6 (SEZ6) is required for the development and maintenance of the nervous system, is a major substrate of the protease BACE1 and is linked to Alzheimer's disease (AD) and psychiatric disorders, but its molecular functions are not well understood. Here, we demonstrate that SEZ6 controls glycosylation and cell surface localization of kainate receptors composed of GluK2/3 subunits. Loss of SEZ6 reduced surface levels of GluK2/3 in primary neurons and reduced kainate-evoked currents in CA1 pyramidal neurons in acute hippocampal slices. Mechanistically, loss of SEZ6 in vitro and in vivo prevented modification of GluK2/3 with the human natural killer-1 (HNK-1) glycan, a modulator of GluK2/3 function. SEZ6 interacted with GluK2 through its ectodomain and promoted post-endoplasmic reticulum transport of GluK2 in the secretory pathway in heterologous cells and primary neurons. Taken together, SEZ6 acts as a new trafficking factor for GluK2/3. This novel function may help to better understand the role of SEZ6 in neurologic and psychiatric diseases.
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Hendi A, Kurashina M, Mizumoto K. Intrinsic and extrinsic mechanisms of synapse formation and specificity in C. elegans. Cell Mol Life Sci 2019; 76:2719-2738. [PMID: 31037336 PMCID: PMC11105629 DOI: 10.1007/s00018-019-03109-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/11/2019] [Accepted: 04/15/2019] [Indexed: 12/18/2022]
Abstract
Precise neuronal wiring is critical for the function of the nervous system and is ultimately determined at the level of individual synapses. Neurons integrate various intrinsic and extrinsic cues to form synapses onto their correct targets in a stereotyped manner. In the past decades, the nervous system of nematode (Caenorhabditis elegans) has provided the genetic platform to reveal the genetic and molecular mechanisms of synapse formation and specificity. In this review, we will summarize the recent discoveries in synapse formation and specificity in C. elegans.
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Affiliation(s)
- Ardalan Hendi
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Mizuki Kurashina
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Kota Mizumoto
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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25
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Csmd2 Is a Synaptic Transmembrane Protein that Interacts with PSD-95 and Is Required for Neuronal Maturation. eNeuro 2019; 6:ENEURO.0434-18.2019. [PMID: 31068362 PMCID: PMC6506821 DOI: 10.1523/eneuro.0434-18.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 04/01/2019] [Accepted: 04/05/2019] [Indexed: 12/21/2022] Open
Abstract
Mutations and copy number variants of the CUB and Sushi multiple domains 2 (CSMD2) gene are associated with neuropsychiatric disease. CSMD2 encodes a single-pass transmembrane protein with a large extracellular domain comprising repeats of CUB and Sushi domains. High expression of CSMD2 in the developing and mature brain suggests possible roles in neuron development or function, but the cellular functions of CSMD2 are not known. In this study, we show that mouse Csmd2 is expressed in excitatory and inhibitory neurons in the forebrain. Csmd2 protein exhibits a somatodendritic localization in the neocortex and hippocampus, with smaller puncta localizing to the neuropil. Using immunohistochemical and biochemical methods, we demonstrate that Csmd2 localizes to dendritic spines and is enriched in the postsynaptic density (PSD). Accordingly, we show that the cytoplasmic tail domain of Csmd2 interacts with synaptic scaffolding proteins of the membrane-associated guanylate kinase (MAGUK) family. The association between Csmd2 and MAGUK member PSD-95 is dependent on a PDZ-binding domain on the Csmd2 tail, which is also required for synaptic targeting of Csmd2. Finally, we show that knock-down of Csmd2 expression in hippocampal neuron cultures results in reduced complexity of dendritic arbors and deficits in dendritic spine density. Knock-down of Csmd2 in immature developing neurons results in reduced filopodia density, whereas Csmd2 knock-down in mature neurons causes significant reductions in dendritic spine density and dendrite complexity. Together, these results point toward a function for Csmd2 in development and maintenance of dendrites and synapses, which may account for its association with certain psychiatric disorders.
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26
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Marsac R, Pinson B, Saint-Marc C, Olmedo M, Artal-Sanz M, Daignan-Fornier B, Gomes JE. Purine Homeostasis Is Necessary for Developmental Timing, Germline Maintenance and Muscle Integrity in Caenorhabditis elegans. Genetics 2019; 211:1297-1313. [PMID: 30700528 PMCID: PMC6456310 DOI: 10.1534/genetics.118.301062] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 01/24/2019] [Indexed: 12/12/2022] Open
Abstract
Purine homeostasis is ensured through a metabolic network widely conserved from prokaryotes to humans. Purines can either be synthesized de novo, reused, or produced by interconversion of extant metabolites using the so-called recycling pathway. Although thoroughly characterized in microorganisms, such as yeast or bacteria, little is known about regulation of the purine biosynthesis network in metazoans. In humans, several diseases are linked to purine metabolism through as yet poorly understood etiologies. Particularly, the deficiency in adenylosuccinate lyase (ADSL)-an enzyme involved both in the purine de novo and recycling pathways-causes severe muscular and neuronal symptoms. In order to address the mechanisms underlying this deficiency, we established Caenorhabditis elegans as a metazoan model organism to study purine metabolism, while focusing on ADSL. We show that the purine biosynthesis network is functionally conserved in C. elegans Moreover, adsl-1 (the gene encoding ADSL in C. elegans) is required for developmental timing, germline stem cell maintenance and muscle integrity. Importantly, these traits are not affected when solely the de novo pathway is abolished, and we present evidence that germline maintenance is linked specifically to ADSL activity in the recycling pathway. Hence, our results allow developmental and tissue specific phenotypes to be ascribed to separable steps of the purine metabolic network in an animal model.
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Affiliation(s)
- Roxane Marsac
- Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux and CNRS UMR5095, 33077 Bordeaux cedex, France
| | - Benoît Pinson
- Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux and CNRS UMR5095, 33077 Bordeaux cedex, France
| | - Christelle Saint-Marc
- Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux and CNRS UMR5095, 33077 Bordeaux cedex, France
| | - María Olmedo
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Department of Molecular Biology and Biochemical Engineering, 41013 Seville, Spain
| | - Marta Artal-Sanz
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Department of Molecular Biology and Biochemical Engineering, 41013 Seville, Spain
| | - Bertrand Daignan-Fornier
- Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux and CNRS UMR5095, 33077 Bordeaux cedex, France
| | - José-Eduardo Gomes
- Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux and CNRS UMR5095, 33077 Bordeaux cedex, France
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27
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D'Alessandro M, Richard M, Stigloher C, Gache V, Boulin T, Richmond JE, Bessereau JL. CRELD1 is an evolutionarily-conserved maturational enhancer of ionotropic acetylcholine receptors. eLife 2018; 7:39649. [PMID: 30407909 PMCID: PMC6245729 DOI: 10.7554/elife.39649] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/05/2018] [Indexed: 12/22/2022] Open
Abstract
The assembly of neurotransmitter receptors in the endoplasmic reticulum limits the number of receptors delivered to the plasma membrane, ultimately controlling neurotransmitter sensitivity and synaptic transfer function. In a forward genetic screen conducted in the nematode C. elegans, we identified crld-1 as a gene required for the synaptic expression of ionotropic acetylcholine receptors (AChR). We demonstrated that the CRLD-1A isoform is a membrane-associated ER-resident protein disulfide isomerase (PDI). It physically interacts with AChRs and promotes the assembly of AChR subunits in the ER. Mutations of Creld1, the human ortholog of crld-1a, are responsible for developmental cardiac defects. We showed that Creld1 knockdown in mouse muscle cells decreased surface expression of AChRs and that expression of mouse Creld1 in C. elegans rescued crld-1a mutant phenotypes. Altogether these results identify a novel and evolutionarily-conserved maturational enhancer of AChR biogenesis, which controls the abundance of functional receptors at the cell surface.
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Affiliation(s)
- Manuela D'Alessandro
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Magali Richard
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Christian Stigloher
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Vincent Gache
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Thomas Boulin
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, United States
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
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28
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Blazie SM, Jin Y. Pharming for Genes in Neurotransmission: Combining Chemical and Genetic Approaches in Caenorhabditis elegans. ACS Chem Neurosci 2018; 9:1963-1974. [PMID: 29432681 DOI: 10.1021/acschemneuro.7b00509] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission is central to nervous system function. Chemical and genetic screens are valuable approaches to probe synaptic mechanisms in living animals. The nematode Caenorhabditis elegans is a prime system to apply these methods to discover genes and dissect the cellular pathways underlying neurotransmission. Here, we review key approaches to understand neurotransmission and the action of psychiatric drugs in C. elegans. We start with early studies on cholinergic excitatory signaling at the neuromuscular junction, and move into mechanisms mediated by biogenic amines. Finally, we discuss emerging work toward understanding the mechanisms driving synaptic plasticity with a focus on regulation of protein translation.
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Affiliation(s)
- Stephen M. Blazie
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
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29
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Philbrook A, Ramachandran S, Lambert CM, Oliver D, Florman J, Alkema MJ, Lemons M, Francis MM. Neurexin directs partner-specific synaptic connectivity in C. elegans. eLife 2018; 7:35692. [PMID: 30039797 PMCID: PMC6057746 DOI: 10.7554/elife.35692] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/21/2018] [Indexed: 01/14/2023] Open
Abstract
In neural circuits, individual neurons often make projections onto multiple postsynaptic partners. Here, we investigate molecular mechanisms by which these divergent connections are generated, using dyadic synapses in C. elegans as a model. We report that C. elegans nrx-1/neurexin directs divergent connectivity through differential actions at synapses with partnering neurons and muscles. We show that cholinergic outputs onto neurons are, unexpectedly, located at previously undefined spine-like protrusions from GABAergic dendrites. Both these spine-like features and cholinergic receptor clustering are strikingly disrupted in the absence of nrx-1. Excitatory transmission onto GABAergic neurons, but not neuromuscular transmission, is also disrupted. Our data indicate that NRX-1 located at presynaptic sites specifically directs postsynaptic development in GABAergic neurons. Our findings provide evidence that individual neurons can direct differential patterns of connectivity with their post-synaptic partners through partner-specific utilization of synaptic organizers, offering a novel view into molecular control of divergent connectivity. Nervous systems are complex networks of interconnected cells called neurons. These networks vary in size from a few hundred cells in worms, to tens of billions in the human brain. Within these networks, each individual neuron forms connections – called synapses – with many others. But these partner neurons are not necessarily alike. In fact, they may be different cell types. How neurons form distinct connections with different partner cells remains unclear. Part of the answer may lie in specialized proteins called cell adhesion molecules. These proteins occur on the cell surface and enable neurons to recognize one another. This helps ensure that the cells form appropriate connections via synapses. Cell adhesion molecules are therefore also known as synaptic organizers. Philbrook et al. have now examined the role of synaptic organizers in wiring up the nervous system of the nematode worm and model organism Caenorhabditis elegans. Motor neurons form connections with two types of partner cell: muscle cells and neurons. Philbrook et al. screened C. elegans that have mutations in genes encoding various synaptic organizers. This revealed that a protein called neurexin must be present for motor neurons to form synapses with other neurons. By contrast, neurexin is not required for the same neurons to establish synapses with muscles. Philbrook et al. found that neuron-to-neuron synapses arise at specialized finger-like projections. These resemble the dendritic spines at which synapses form in the brains of mammals, and had not been previously identified in C. elegans. In worms that lack neurexin, these spine-like structures do not form correctly, disrupting the formation of neuron-to-neuron connections. Previous work has implicated neurexin in synapse formation in the mammalian brain. But this is the first study to reveal a role for neurexin in establishing partner-specific synaptic connections. Mutations in synaptic organizers, including neurexin, contribute to disorders of brain development. These include schizophrenia and autism spectrum disorders. Learning more about how neurexin helps establish specific synaptic connections may help us understand how these disorders arise.
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Affiliation(s)
- Alison Philbrook
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Shankar Ramachandran
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Christopher M Lambert
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Devyn Oliver
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Jeremy Florman
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Mark J Alkema
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Michele Lemons
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States.,Department of Natural Sciences, Assumption College, Worcester, United States
| | - Michael M Francis
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
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30
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The Claudin-like Protein HPO-30 Is Required to Maintain LAChRs at the C. elegans Neuromuscular Junction. J Neurosci 2018; 38:7072-7087. [PMID: 29950505 PMCID: PMC6083452 DOI: 10.1523/jneurosci.3487-17.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 06/07/2018] [Accepted: 06/07/2018] [Indexed: 12/22/2022] Open
Abstract
Communications across chemical synapses are primarily mediated by neurotransmitters and their postsynaptic receptors. There are diverse molecular systems to localize and regulate the receptors at the synapse. Here, we identify HPO-30, a member of the claudin superfamily of membrane proteins, as a positive regulator for synaptic localization of levamisole-dependent AChRs (LAChRs) at the Caenorhabditis elegans neuromuscular junction (NMJ). The HPO-30 protein localizes at the NMJ and shows genetic and physical association with the LAChR subunits LEV-8, UNC-29, and UNC-38. Using genetic and electrophysiological assays in the hermaphrodite C. elegans, we demonstrate that HPO-30 functions through Neuroligin at the NMJ to maintain postsynaptic LAChR levels at the synapse. Together, this work suggests a novel function for a tight junction protein in maintaining normal receptor levels at the NMJ. SIGNIFICANCE STATEMENT Claudins are a large superfamily of membrane proteins. Their role in maintaining the functional integrity of tight junctions has been widely explored. Our experiments suggest a critical role for the claudin-like protein, HPO-30, in maintaining synaptic levamisole-dependent AChR (LAChR) levels. LAChRs contribute to <20% of the acetylcholine-mediated conductance in adult Caenorhabditis elegans; however, they play a significant functional role in worm locomotion. This study provides a new perspective in the study of LAChR physiology.
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31
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Soteros BM, Cong Q, Palmer CR, Sia GM. Sociability and synapse subtype-specific defects in mice lacking SRPX2, a language-associated gene. PLoS One 2018; 13:e0199399. [PMID: 29920554 PMCID: PMC6007900 DOI: 10.1371/journal.pone.0199399] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/06/2018] [Indexed: 01/05/2023] Open
Abstract
The FoxP2 transcription factor and its target genes have been implicated in developmental brain diseases with a prominent language component, such as developmental verbal dyspraxia and specific language impairment. How FoxP2 affects neural circuitry development remains poorly understood. The sushi domain protein SRPX2 is a target of FoxP2, and mutations in SRPX2 are associated with language defects in humans. We have previously shown that SRPX2 is a synaptogenic protein that increases excitatory synapse density. Here we provide the first characterization of mice lacking the SRPX2 gene, and show that these mice exhibit defects in both neural circuitry and communication and social behaviors. Specifically, we show that mice lacking SRPX2 show a specific reduction in excitatory VGlut2 synapses in the cerebral cortex, while VGlut1 and inhibitory synapses were largely unaffected. SRPX2 KO mice also exhibit an abnormal ultrasonic vocalization ontogenetic profile in neonatal pups, and reduced preference for social novelty. These data demonstrate a functional role for SRPX2 during brain development, and further implicate FoxP2 and its targets in regulating the development of vocalization and social circuits.
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Affiliation(s)
- Breeanne M. Soteros
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Qifei Cong
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Christian R. Palmer
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, United States of America
| | - Gek-Ming Sia
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
- * E-mail:
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32
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Martin AA, Richmond JE. The sarco(endo)plasmic reticulum calcium ATPase SCA-1 regulates the Caenorhabditis elegans nicotinic acetylcholine receptor ACR-16. Cell Calcium 2018; 72:104-115. [PMID: 29748129 DOI: 10.1016/j.ceca.2018.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 12/26/2022]
Abstract
Nicotinic acetylcholine receptors (nAChR) are present in many excitable tissues and are found both pre and post-synaptically. Through their non-specific cationic permeability, these nAChRs have excitatory roles in neurotransmission, neuromodulation, synaptic plasticity, and neuroprotection. Thus, nAChR mislocalization or functional deficits are associated with many neurological disease states. Therefore identifying the mechanisms that regulate nAChR expression and function will inform our understanding of normal as well as pathological physiological conditions and offer avenues for potential therapeutic advances. Taking advantage of the genetic tractability of the soil nematode Caenorhabditis elegans, a forward genetic screen was performed to isolate regulators of the vertebrate α7 nAChR homologue ACR-16. From this screen a novel regulator of the ACR-16 receptor was identified, the sarco(endo)plasmic reticulum calcium ATPase sca-1. The sca-1 mutant affects ACR-16 receptor level at the NMJ, receptor functionality, and synaptic transmission. Responses to pressure-ejected nicotine in sca-1 mutants are indistinguishable from wild type, which implies the ACR-16 receptors are mislocalized at the NMJ. Changes in cytosolic baseline calcium levels in sca-1 and other mutants indicates a calcium-driven regulation mechanism of the α7-like NAChR ACR-16.
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Affiliation(s)
- Ashley A Martin
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, United States.
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, United States
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Yin W, Wei X, Jiang J, Fan K, Zhao J, Sun N, Wang Z, Sun Y, Ma H, Zhao X, Li H. Complement receptor activity of recombinant porcine CR1-like protein expressed in a eukaryotic system. Immunol Res 2017; 64:1025-32. [PMID: 26903010 DOI: 10.1007/s12026-016-8792-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Primate complement receptor type 1 (CR1) protein, a single-chain transmembrane glycoprotein, plays an important role in immune adherence and clearing complement-opsonized immune complexes. Here, the mRNA of the porcine primate-like complement receptor (CR1-like) gene was analyzed, and two domain sequences with potential functions were cloned into the pwPICZalpha vector for expression in Pichia pastoris. The recombinant proteins were purified with both Protein Pure Ni-NTA resin and strong anion exchange resin. The activities of the purified recombinant proteins were evaluated by SDS-PAGE, western blotting, and complement receptor assays. The results indicated that two domains of the CR1-like protein, CCP36 and CCP811 with molecular weights of 29.8 kDa and 30 kDa, respectively, were successfully expressed in P. pastoris. These two recombinant proteins possess some of the functions of the primate CR1 protein. Using these two proteins coupled with an antibody blocking technique, we also showed that CR1-like is expressed on natural porcine erythrocytes.
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Affiliation(s)
- Wei Yin
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Xiaoming Wei
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Junbing Jiang
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Kuohai Fan
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Junxing Zhao
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Na Sun
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Zhiwei Wang
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Yaogui Sun
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Haili Ma
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Xin Zhao
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China
| | - Hongquan Li
- College of Animal Science and Veterinary Medicine, Shanxi Agriculture University, Taigu, 030801, Shanxi, People's Republic of China.
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34
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Yamasaki T, Hoyos-Ramirez E, Martenson JS, Morimoto-Tomita M, Tomita S. GARLH Family Proteins Stabilize GABA A Receptors at Synapses. Neuron 2017; 93:1138-1152.e6. [PMID: 28279354 DOI: 10.1016/j.neuron.2017.02.023] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 05/26/2016] [Accepted: 02/09/2017] [Indexed: 10/20/2022]
Abstract
Ionotropic neurotransmitter receptors mediate fast synaptic transmission by functioning as ligand-gated ion channels. Fast inhibitory transmission in the brain is mediated mostly by ionotropic GABAA receptors (GABAARs), but their essential components for synaptic localization remain unknown. Here, we identify putative auxiliary subunits of GABAARs, which we term GARLHs, consisting of LH4 and LH3 proteins. LH4 forms a stable tripartite complex with GABAARs and neuroligin-2 in the brain. Moreover, LH4 is required for the synaptic localization of GABAARs and inhibitory synaptic transmission in the hippocampus. Our findings propose GARLHs as the first identified auxiliary subunits for anion channels. These findings provide new insights into the regulation of inhibitory transmission and the molecular constituents of native anion channels in vivo.
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Affiliation(s)
- Tokiwa Yamasaki
- Department of Cellular and Molecular Physiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Erika Hoyos-Ramirez
- Department of Cellular and Molecular Physiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - James S Martenson
- Department of Cellular and Molecular Physiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Megumi Morimoto-Tomita
- Department of Cellular and Molecular Physiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susumu Tomita
- Department of Cellular and Molecular Physiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA.
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35
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Preventing Illegitimate Extrasynaptic Acetylcholine Receptor Clustering Requires the RSU-1 Protein. J Neurosci 2017; 36:6525-37. [PMID: 27307240 DOI: 10.1523/jneurosci.3733-15.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 05/06/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Diffuse extrasynaptic neurotransmitter receptors constitute an abundant pool of receptors that can be recruited to modulate synaptic strength. Whether the diffuse distribution of receptors in extrasynaptic membranes is a default state or is actively controlled remains essentially unknown. Here we show that RSU-1 (Ras Suppressor-1) is required for the proper distribution of extrasynaptic acetylcholine receptors (AChRs) in Caenorhabditis elegans muscle cells. RSU-1 is an evolutionary conserved cytoplasmic protein that contains multiple leucine-rich repeats (LRRs) and interacts with integrin-dependent adhesion complexes. In rsu-1 mutants, neuromuscular junctions differentiate as in the wild type, but AChRs assemble into ectopic clusters that progressively enlarge during development. As a consequence, the synaptic content of AChRs is reduced. Our study provides the first evidence that an RSU-1-dependent active mechanism maintains extrasynaptic receptors dispersed and indirectly regulates synapse maturation. SIGNIFICANCE STATEMENT Using Caenorhabditis elegans neuromuscular junction as a model synapse, we uncovered a novel mechanism that regulates the distribution of acetylcholine receptors (AChRs). In an unbiased visual screen for mutants with abnormal AChR distribution, we isolated the ras suppressor 1 (rsu-1) mutant based on the presence of large extrasynaptic clusters. We show that disrupting rsu-1 causes spontaneous clustering of extrasynaptic receptors that are normally dispersed, independently of synaptic cues. These clusters outcompete synaptic domains and cause a decrease of synaptic receptor content. These results indicate that the diffuse state of extrasynaptic receptors is not a default state that is simply explained by the lack of synaptic cues but necessitates additional proteins to prevent spontaneous clustering, a concept that is relevant for developmental and pathological situations.
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El Mouridi S, Lecroisey C, Tardy P, Mercier M, Leclercq-Blondel A, Zariohi N, Boulin T. Reliable CRISPR/Cas9 Genome Engineering in Caenorhabditis elegans Using a Single Efficient sgRNA and an Easily Recognizable Phenotype. G3 (BETHESDA, MD.) 2017; 7:1429-1437. [PMID: 28280211 PMCID: PMC5427500 DOI: 10.1534/g3.117.040824] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/02/2017] [Indexed: 12/26/2022]
Abstract
CRISPR/Cas9 genome engineering strategies allow the directed modification of the Caenorhabditis elegans genome to introduce point mutations, generate knock-out mutants, and insert coding sequences for epitope or fluorescent tags. Three practical aspects, however, complicate such experiments. First, the efficiency and specificity of single-guide RNAs (sgRNA) cannot be reliably predicted. Second, the detection of animals carrying genome edits can be challenging in the absence of clearly visible or selectable phenotypes. Third, the sgRNA target site must be inactivated after editing to avoid further double-strand break events. We describe here a strategy that addresses these complications by transplanting the protospacer of a highly efficient sgRNA into a gene of interest to render it amenable to genome engineering. This sgRNA targeting the dpy-10 gene generates genome edits at comparatively high frequency. We demonstrate that the transplanted protospacer is cleaved at the same time as the dpy-10 gene. Our strategy generates scarless genome edits because it no longer requires the introduction of mutations in endogenous sgRNA target sites. Modified progeny can be easily identified in the F1 generation, which drastically reduces the number of animals to be tested by PCR or phenotypic analysis. Using this strategy, we reliably generated precise deletion mutants, transcriptional reporters, and translational fusions with epitope tags and fluorescent reporter genes. In particular, we report here the first use of the new red fluorescent protein mScarlet in a multicellular organism. wrmScarlet, a C. elegans-optimized version, dramatically surpassed TagRFP-T by showing an eightfold increase in fluorescence in a direct comparison.
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Affiliation(s)
- Sonia El Mouridi
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Claire Lecroisey
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Philippe Tardy
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Marine Mercier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Alice Leclercq-Blondel
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Nora Zariohi
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
| | - Thomas Boulin
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, F-69622 Villeurbanne, France
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Bocharova AV, Stepanov VA, Marusin AV, Kharkov VN, Vagaitseva KV, Fedorenko OY, Bokhan NA, Semke AV, Ivanova SA. Association study of genetic markers of schizophrenia and its cognitive endophenotypes. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417010033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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The Matrix Proteins Hasp and Hig Exhibit Segregated Distribution within Synaptic Clefts and Play Distinct Roles in Synaptogenesis. J Neurosci 2016; 36:590-606. [PMID: 26758847 DOI: 10.1523/jneurosci.2300-15.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED The synaptic cleft is the space through which neurotransmitters convey neural information between two synaptic terminals. This space is presumably filled with extracellular matrix molecules involved in synaptic function or differentiation. However, little is known about the identities of the matrix components, and it remains unclear how these molecules organize the matrix in synaptic clefts. In this study, we identified Hasp, a Drosophila secretory protein containing CCP and WAP domains. Molecular genetic analysis revealed that Hasp diffuses extracellularly and is predominantly captured at synaptic clefts of cholinergic synapses. Furthermore, Hasp regulates levels of DLG and the nAChR subunits Dα6 and Dα7 at postsynaptic terminals. Hasp is required for trapping of another matrix protein, Hig, which is also secreted and diffused in the brain, at synaptic clefts of cholinergic synapses; however, Hig is dispensable for localization of Hasp at synaptic clefts. In addition, in the brains of triple mutants for the nAChR subunits Dα5, Dα6, and Dα7, the level of Hig, but not Hasp, was markedly reduced in synaptic regions, indicating that these nAChR subunits are required to anchor Hig to synaptic clefts. High-resolution microscopy revealed that Hasp and Hig exhibit segregated distribution within individual synaptic clefts, reflecting their differing roles in synaptogenesis. These data provide insight into how Hasp and Hig construct the synaptic cleft matrix and regulate the differentiation of cholinergic synapses, and also illuminate a previously unidentified architecture within synaptic clefts. SIGNIFICANCE STATEMENT The synapse has been extensively studied because it is essential for neurotransmission. By contrast, the space between the synaptic terminals, the synaptic cleft, is still an undeveloped research area despite its ubiquity in synapses. In fruit fly brains, we obtained evidence that the matrix protein Hasp and the previously identified Hig, both of which are secreted extracellularly, localize predominantly to synaptic clefts of cholinergic synapses, and modulate the levels of nAChR subunits on postsynaptic membranes. However, Hasp and Hig play differential roles in matrix formation and exhibit segregated distribution within synaptic clefts. These results reveal the molecular mechanisms of synaptic matrix construction and illuminate a molecular architecture within synaptic clefts previously unrevealed in any animal species.
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Cherra SJ, Jin Y. A Two-Immunoglobulin-Domain Transmembrane Protein Mediates an Epidermal-Neuronal Interaction to Maintain Synapse Density. Neuron 2016; 89:325-36. [PMID: 26777275 PMCID: PMC4871750 DOI: 10.1016/j.neuron.2015.12.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/17/2015] [Accepted: 12/08/2015] [Indexed: 02/06/2023]
Abstract
Synaptic maintenance is essential for neural circuit function. In the C. elegans locomotor circuit, motor neurons are in direct contact with the epidermis. Here, we reveal a novel epidermal-neuronal interaction mediated by a two-immunoglobulin domain transmembrane protein, ZIG-10, that is necessary for maintaining cholinergic synapse density. ZIG-10 is localized at the cell surface of epidermis and cholinergic motor neurons, with high levels at areas adjacent to synapses. Loss of zig-10 increases the number of cholinergic excitatory synapses and exacerbates convulsion behavior in a seizure model. Mis-expression of zig-10 in GABAergic inhibitory neurons reduces GABAergic synapse number, dependent on the presence of ZIG-10 in the epidermis. Furthermore, ZIG-10 interacts with the tyrosine kinase SRC-2 to regulate the phagocytic activity of the epidermis to restrict cholinergic synapse number. Our studies demonstrate the highly specific roles of non-neuronal cells in modulating neural circuit function, through neuron-type-specific maintenance of synapse density.
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Affiliation(s)
- Salvatore J. Cherra
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yishi Jin
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
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Howell K, White JG, Hobert O. Spatiotemporal control of a novel synaptic organizer molecule. Nature 2015; 523:83-7. [PMID: 26083757 PMCID: PMC9134992 DOI: 10.1038/nature14545] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 05/12/2015] [Indexed: 12/13/2022]
Abstract
Synapse formation is a process tightly controlled in space and time. How gene regulatory mechanisms specify spatial and temporal aspects of synapse formation is not well understood. In the nematode C.elegans, two subtypes of the D-type inhibitory motor neuron (MN) classes, the dorsal D (DD) and ventral D (VD) neurons, extend axons along both the dorsal and ventral nerve cords 1. The embryonically generated DD MNs initially innervate ventral muscles in the first (L1) larval stage and receive their synaptic input from cholinergic MNs in the dorsal cord. They rewire by the end of the L1 molt to innervate dorsal muscles and to be innervated by newly formed ventral cholinergic MNs 1. VD MNs develop after the L1 molt; they take over the innervation of ventral muscles and receive their synaptic input from dorsal cholinergic MNs. We show here that the spatiotemporal control of synaptic wiring of the D-type neurons is controlled by an intersectional transcriptional strategy in which the UNC-30 Pitx-type homeodomain transcription factor acts together in embryonic and early larval stages with the temporally controlled LIN-14 transcription factor to prevent premature synapse rewiring of the DD MNs and, together with the UNC-55 nuclear hormone receptor, to prevent aberrant VD synaptic wiring in later larval and adult stages. A key effector of this intersectional transcription factor combination is a novel synaptic organizer molecule, the single immunoglobulin domain protein OIG-1. OIG-1 is perisynaptically localized along the synaptic outputs of the D-type MNs in a temporally controlled manner and is required for appropriate selection of both pre- and post-synaptic partners.
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C. elegans Punctin Clusters GABAA Receptors via Neuroligin Binding and UNC-40/DCC Recruitment. Neuron 2015; 86:1407-19. [DOI: 10.1016/j.neuron.2015.05.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/13/2015] [Accepted: 03/27/2015] [Indexed: 12/21/2022]
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Cherra SJ, Jin Y. Advances in synapse formation: forging connections in the worm. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:85-97. [PMID: 25472860 PMCID: PMC4339659 DOI: 10.1002/wdev.165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 10/09/2014] [Accepted: 10/24/2014] [Indexed: 12/27/2022]
Abstract
UNLABELLED Synapse formation is the quintessential process by which neurons form specific connections with their targets to enable the development of functional circuits. Over the past few decades, intense research efforts have identified thousands of proteins that localize to the pre- and postsynaptic compartments. Genetic dissection has provided important insights into the nexus of the molecular and cellular network, and has greatly advanced our knowledge about how synapses form and function physiologically. Moreover, recent studies have highlighted the complex regulation of synapse formation with the identification of novel mechanisms involving cell interactions from non-neuronal sources. In this review, we cover the conserved pathways required for synaptogenesis and place specific focus on new themes of synapse modulation arising from studies in Caenorhabditis elegans. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.
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Affiliation(s)
- Salvatore J. Cherra
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego
- Howard Hughes Medical Institute
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Nadjar Y, Triller A, Bessereau JL, Dumoulin A. The Susd2 protein regulates neurite growth and excitatory synaptic density in hippocampal cultures. Mol Cell Neurosci 2015; 65:82-91. [PMID: 25724483 DOI: 10.1016/j.mcn.2015.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 12/12/2014] [Accepted: 02/12/2015] [Indexed: 10/24/2022] Open
Abstract
Complement control protein (CCP) domains have adhesion properties and are commonly found in proteins that control the complement immune system. However, an increasing number of proteins containing CCP domains have been reported to display neuronal functions. Susd2 is a transmembrane protein containing one CCP domain. It was previously identified as a tumor-reversing protein, but has no characterized function in the CNS. The present study investigates the expression and function of Susd2 in the rat hippocampus. Characterization of Susd2 during development showed a peak in mRNA expression two weeks after birth. In hippocampal neuronal cultures, the same expression profile was observed at 15days in vitro for both mRNA and protein, a time consistent with synaptogenesis in our model. At the subcellular level, Susd2 was located on the soma, axons and dendrites, and appeared to associate preferentially with excitatory synapses. Inhibition of Susd2 by shRNAs led to decreased numbers of excitatory synaptic profiles, exclusively. Also, morphological parameters were studied on young (5DIV) developing neurons. After Susd2 inhibition, an increase in dendritic tree length but a decrease in axon elongation were observed, suggesting changes in adhesion properties. Our results demonstrate a dual role for Susd2 at different developmental stages, and raise the question whether Susd2 and other CCP-containing proteins expressed in the CNS could be function-related.
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Affiliation(s)
- Yann Nadjar
- Ecole Normale Supérieure, IBENS, INSERM U1024, 75005 Paris, France
| | - Antoine Triller
- Ecole Normale Supérieure, IBENS, INSERM U1024, 75005 Paris, France
| | | | - Andrea Dumoulin
- Ecole Normale Supérieure, IBENS, INSERM U1024, 75005 Paris, France.
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Stepanov VA, Bocharova AV, Marusin AV, Zhukova NG, Alifirova VM, Zhukova IA. Replicative association analysis of genetic markers of cognitive traits with Alzheimer’s disease in the Russian population. Mol Biol 2014. [DOI: 10.1134/s0026893314060168] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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45
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Barrantes FJ. Cell-surface translational dynamics of nicotinic acetylcholine receptors. Front Synaptic Neurosci 2014; 6:25. [PMID: 25414663 PMCID: PMC4220116 DOI: 10.3389/fnsyn.2014.00025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 10/08/2014] [Indexed: 12/20/2022] Open
Abstract
Synapse efficacy heavily relies on the number of neurotransmitter receptors available at a given time. In addition to the equilibrium between the biosynthetic production, exocytic delivery and recycling of receptors on the one hand, and the endocytic internalization on the other, lateral diffusion and clustering of receptors at the cell membrane play key roles in determining the amount of active receptors at the synapse. Mobile receptors traffic between reservoir compartments and the synapse by thermally driven Brownian motion, and become immobilized at the peri-synaptic region or the synapse by: (a) clustering mediated by homotropic inter-molecular receptor–receptor associations; (b) heterotropic associations with non-receptor scaffolding proteins or the subjacent cytoskeletal meshwork, leading to diffusional “trapping,” and (c) protein-lipid interactions, particularly with the neutral lipid cholesterol. This review assesses the contribution of some of these mechanisms to the supramolecular organization and dynamics of the paradigm neurotransmitter receptor of muscle and neuronal cells -the nicotinic acetylcholine receptor (nAChR). Currently available information stemming from various complementary biophysical techniques commonly used to interrogate the dynamics of cell-surface components is critically discussed. The translational mobility of nAChRs at the cell surface differs between muscle and neuronal receptors in terms of diffusion coefficients and residence intervals at the synapse, which cover an ample range of time regimes. A peculiar feature of brain α7 nAChR is its ability to spend much of its time confined peri-synaptically, vicinal to glutamatergic (excitatory) and GABAergic (inhibitory) synapses. An important function of the α7 nAChR may thus be visiting the territories of other neurotransmitter receptors, differentially regulating the dynamic equilibrium between excitation and inhibition, depending on its residence time in each domain.
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Affiliation(s)
- Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Institute of Biomedical Research, Faculty of Medical Sciences, Pontifical Catholic University of Argentina-National Scientific and Technical Research Council Buenos Aires, Argentina
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46
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Exciting prospects for precise engineering of Caenorhabditis elegans genomes with CRISPR/Cas9. Genetics 2014; 195:635-42. [PMID: 24190921 DOI: 10.1534/genetics.113.156521] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
With remarkable speed, the CRISPR-Cas9 nuclease has become the genome-editing tool of choice for essentially all genetically tractable organisms. Targeting specific DNA sequences is conceptually simple because the Cas9 nuclease can be guided by a single, short RNA (sgRNA) to introduce double-strand DNA breaks (DSBs) at precise locations. Here I contrast and highlight protocols recently developed by eight different research groups, six of which are published in GENETICS, to modify the Caenorhabditis elegans genome using CRISPR/Cas9. This reverse engineering tool levels the playing field for experimental geneticists.
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47
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Pinan-Lucarré B, Tu H, Pierron M, Cruceyra PI, Zhan H, Stigloher C, Richmond JE, Bessereau JL. C. elegans Punctin specifies cholinergic versus GABAergic identity of postsynaptic domains. Nature 2014; 511:466-70. [DOI: 10.1038/nature13313] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 04/07/2014] [Indexed: 11/09/2022]
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Briseño-Roa L, Bessereau JL. Proteolytic processing of the extracellular scaffolding protein LEV-9 is required for clustering acetylcholine receptors. J Biol Chem 2014; 289:10967-10974. [PMID: 24619422 DOI: 10.1074/jbc.c113.534677] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Correct positioning of neurotransmitter-gated receptors at postsynapses is essential for synaptic transmission. At Caenorhabditis elegans neuromuscular junctions, clustering of levamisole-sensitive acetylcholine receptors (L-AChRs) requires the muscle-secreted scaffolding protein LEV-9, a multidomain factor containing complement control protein (CCP) modules. Here we show that LEV-9 needs to be cleaved at its C terminus to exert its function. LEV-9 cleavage is not required for trafficking nor secretion but directly controls scaffolding activity. The cleavage site is evolutionarily conserved, and post-translational cleavage ensures the structural and functional decoupling between different isoforms encoded by the lev-9 gene. Data mining indicates that most human CCP-containing factors are likely cleaved C-terminally from CCP tandems, suggesting that not only domain architectures but also cleavage location can be conserved in distant architecturally related proteins.
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Affiliation(s)
- Luis Briseño-Roa
- Institute of Biology of Ecole Normale Supérieure, 75005 Paris,; INSERM, U1024, 75005 Paris,; Institut Jacques Monod UMR CNRS 7592, 75013 Paris, France.
| | - Jean-Louis Bessereau
- Institute of Biology of Ecole Normale Supérieure, 75005 Paris,; INSERM, U1024, 75005 Paris,; University Claude Bernard Lyon 1, Centre de Génétique et de Physiologie Moléculaire et Cellulaire (CGphiMC) UMR CNRS 5534, 69622 Villeurbanne, and.
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Xu W, Cohen-Woods S, Chen Q, Noor A, Knight J, Hosang G, Parikh SV, De Luca V, Tozzi F, Muglia P, Forte J, McQuillin A, Hu P, Gurling HMD, Kennedy JL, McGuffin P, Farmer A, Strauss J, Vincent JB. Genome-wide association study of bipolar disorder in Canadian and UK populations corroborates disease loci including SYNE1 and CSMD1. BMC MEDICAL GENETICS 2014; 15:2. [PMID: 24387768 PMCID: PMC3901032 DOI: 10.1186/1471-2350-15-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 12/20/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND Recently, genome-wide association studies (GWAS) for cases versus controls using single nucleotide polymorphism microarray data have shown promising findings for complex neuropsychiatric disorders, including bipolar disorder (BD). METHODS Here we describe a comprehensive genome-wide study of bipolar disorder (BD), cross-referencing analysis from a family-based study of 229 small families with association analysis from over 950 cases and 950 ethnicity-matched controls from the UK and Canada. Further, loci identified in these analyses were supported by pathways identified through pathway analysis on the samples. RESULTS Although no genome-wide significant markers were identified, the combined GWAS findings have pointed to several genes of interest that support GWAS findings for BD from other groups or consortia, such as at SYNE1 on 6q25, PPP2R2C on 4p16.1, ZNF659 on 3p24.3, CNTNAP5 (2q14.3), and CDH13 (16q23.3). This apparent corroboration across multiple sites gives much confidence to the likelihood of genetic involvement in BD at these loci. In particular, our two-stage strategy found association in both our combined case/control analysis and the family-based analysis on 1q21.2 (closest gene: sphingosine-1-phosphate receptor 1 gene, S1PR1) and on 1q24.1 near the gene TMCO1, and at CSMD1 on 8p23.2, supporting several previous GWAS reports for BD and for schizophrenia. Pathway analysis suggests association of pathways involved in calcium signalling, neuropathic pain signalling, CREB signalling in neurons, glutamate receptor signalling and axonal guidance signalling. CONCLUSIONS The findings presented here show support for a number of genes previously implicated genes in the etiology of BD, including CSMD1 and SYNE1, as well as evidence for previously unreported genes such as the brain-expressed genes ADCY2, NCALD, WDR60, SCN7A and SPAG16.
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Affiliation(s)
- Wei Xu
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Sarah Cohen-Woods
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Qian Chen
- Cancer Care Ontario, Toronto, Canada
| | - Abdul Noor
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Jo Knight
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Georgina Hosang
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Sagar V Parikh
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | | | - Federica Tozzi
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Pierandrea Muglia
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- Exploratory Medicine & Early Development, NeuroSearch, Copenhagen, Denmark
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Julia Forte
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Via Fleming 4, Verona, Italy
- GSK Research & Development, Medical Genetics, Clinical Pharmacology and Discovery Medicine, Greenford Road, Greenford, Middlesex UB6 OHE, UK
| | - Andrew McQuillin
- Molecular Psychiatry Laboratory, Mental Health Sciences Unit, Faculty of Brain Sciences, University College London, London, UK
| | - Pingzhao Hu
- The Centre for Applied Genomics, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Hugh MD Gurling
- Molecular Psychiatry Laboratory, Mental Health Sciences Unit, Faculty of Brain Sciences, University College London, London, UK
| | - James L Kennedy
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Peter McGuffin
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - Anne Farmer
- MRC SGDP Centre, King’s College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
| | - John Strauss
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - John B Vincent
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), R-32, 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- The Institute of Medical Science, University of Toronto, Toronto, Canada
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Sia GM, Clem RL, Huganir RL. The human language-associated gene SRPX2 regulates synapse formation and vocalization in mice. Science 2013; 342:987-91. [PMID: 24179158 DOI: 10.1126/science.1245079] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Synapse formation in the developing brain depends on the coordinated activity of synaptogenic proteins, some of which have been implicated in a number of neurodevelopmental disorders. Here, we show that the sushi repeat-containing protein X-linked 2 (SRPX2) gene encodes a protein that promotes synaptogenesis in the cerebral cortex. In humans, SRPX2 is an epilepsy- and language-associated gene that is a target of the foxhead box protein P2 (FoxP2) transcription factor. We also show that FoxP2 modulates synapse formation through regulating SRPX2 levels and that SRPX2 reduction impairs development of ultrasonic vocalization in mice. Our results suggest FoxP2 modulates the development of neural circuits through regulating synaptogenesis and that SRPX2 is a synaptogenic factor that plays a role in the pathogenesis of language disorders.
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Affiliation(s)
- G M Sia
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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