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Jean Cartaud - One of the best experts on this subject based on the ideXlab platform.
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eLS - Postsynaptic Membranes at the Neuromuscular Junction: Molecular Organisation
Encyclopedia of Life Sciences, 2010Co-Authors: Jean Cartaud, Ekaterini Kordeli, Annie CartaudAbstract:Accurate neurotransmission between motor nerve and muscle fibres at the vertebrate cholinergic neuromuscular junction (NMJ) depends on the differentiation of highly specialised structures both pre- and Postsynaptically. The accumulation of nicotinic acetylcholine receptors (AChRs) and voltage-gated sodium channels represents the hallmark of Postsynaptic Membrane differentiation. Several synaptic organising proteins are required for the aggregation of Postsynaptic AChRs. The muscle-specific receptor tyrosine kinase (MuSK) provides a structural scaffold necessary to initiate aggregates of Postsynaptic molecules. Agrin – a nerve-derived extracellular matrix glycoprotein – is required for AChR clustering probably by activating MuSK activity. Rapsyn – the AChR-associated peripheral protein acting downstream of agrin–MuSK signalling – is essential for AChR clustering. These proteins, together with a wealth of other components of the synapse, cooperate in multiple ways to play both structural and signalling roles in synaptic differentiation. Synaptopathies of the NMJ result from mutations in several key players of synaptic differentiation. Key Concepts: Efficient communication between neurons or between neurons and their targets requires the enrichment of synaptic proteins, in particular, ligand-gated ion channels at Postsynaptic sites. The NMJ represents a particularly striking example of accumulation of nicotinic acetylcholine receptors in the Postsynaptic Membrane and is an ideal model to study receptor clustering. Formation and maintenance of the Postsynaptic Membrane is a complex mechanism involving synaptic organising molecules derived both from nerve and muscle. The muscle tyrosine kinase, MuSK, is the master organiser of the NMJ capable to initiate clustering of Postsynaptic components, even in the absence of neuronal cues. Mutations in several components of the Postsynaptic Membrane (not only in AChR subunits genes but also in agrin, ColQ, DOK-7, laminin, MuSK, rapsyn, etc.) result in severe dysfunction of the NMJ: the congenital myasthenic syndromes. Keywords: acetylcholinesterase; agrin; congenital myasthenic syndromes; nicotinic acetylcholine receptor; voltage-sensitive sodium channel; rapsyn; synapse
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Differential targeting of components of the dystrophin complex to the Postsynaptic Membrane.
The European journal of neuroscience, 2001Co-Authors: Sophie Marchand, Françoise Stetzkowski-marden, Jean CartaudAbstract:Accumulating evidence points to the participation of dystroglycan in the clustering of nicotinic acetylcholine receptors at the neuromuscular junction [Cote et al. (1999) Nature Genet., 3, 338--342]. Dystroglycan is part of a multimolecular complex, either associated with dystrophin (the dystrophin-associated protein complex) at the sarcolemma or with utrophin (the utrophin-associated protein complex) at the neuromuscular junction. Understanding the assembly of this complex at the developing synapse led us to investigate, in Torpedo electrocyte, the intracellular routing and the targeting of several of its components, including dystroglycan, syntrophin, dystrophin and dystrobrevin. We previously demonstrated that acetylcholine receptors and rapsyn, the 43-kDa receptor-associated protein at the synapse, are cotargeted to the Postsynaptic Membrane via the exocytic pathway [Marchand et al. (2000) J. Neurosci., 20, 521--528]. Using cell fractionation, immunopurification and immuno-electron microscope techniques, we show that beta-dystroglycan, an integral glycoprotein that constitutes the core of the dystrophin-associated protein complex localized at the innervated Membrane, is transported together with acetylcholine receptor and rapsyn in post-Golgi vesicles en route to the Postsynaptic Membrane. Syntrophin, a peripheral cytoplasmic protein of the complex, associates initially with these exocytic vesicles. Conversely, dystrophin and dystrobrevin were absent from these post-Golgi vesicles and associate directly with the Postsynaptic Membrane. This study provides the first evidence for a separate targeting of the various components of the dystrophin-associated protein complex and a step-by-step assembly at the Postsynaptic Membrane.
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The torpedo electrocyte: a model system to study Membrane-cytoskeleton interactions at the Postsynaptic Membrane.
Microscopy research and technique, 2000Co-Authors: Jean Cartaud, Annie Cartaud, Sophie Marchand, Ekaterini Kordeli, Marie Aline Ludosky, Françoise Stetzkowski-mardenAbstract:Many aspects of the organization of the electromotor synapse of electric fish resemble the nerve-muscle junction. In particular, the Postsynaptic Membrane in both systems share most of their proteins. As a remarquable source of cholinergic synapses, the Torpedo electrocyte model has served to identify the most important components involved in synaptic transmission such as the nicotinic acetylcholine receptor and the enzyme acetylcholinesterase, as well as proteins associated with the subsynaptic cytoskeleton and the extracellular matrix involved in the assembly of the Postsynaptic Membrane, namely the 43-kDa protein-rapsyn, the dystrophin/ utrophin complex, agrin, and others. This review encompasses some representative experiments that helped to clarify essential aspects of the supramolecular organization and assembly of the postsyn- aptic apparatus of cholinergic synapses. Microsc. Res. Tech. 49:73- 83, 2000. © 2000 Wiley-Liss, Inc.
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The Myristoylated Protein Rapsyn is Cotargeted with the Nicotinic Acetylcholine Receptor to the Postsynaptic Membrane via the Exocytic Pathway
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2000Co-Authors: Sophie Marchand, Françoise Stetzkowski-marden, Fabrizia Bignami, Jean CartaudAbstract:Rapsyn, a 43 kDa protein required to cluster nicotinic acetylcholine receptors (AChRs) at the neuromuscular junction, is tightly associated with the Postsynaptic Membrane via an N-terminal myristoylated site. Recent studies have shown that some acylated proteins associate with the exocytic pathway to become targeted to their correct destination. In this work, we used Torpedo electrocyte to investigate the intracellular routing of rapsyn compared to those of AChR and Na,K-ATPase, the respective components of the innervated and noninnervated Membranes. We previously demonstrated that these latter two proteins are sorted and targeted to plasma Membrane via distinct populations of post-Golgi vesicles ([Camus et al., 1998][1]). Biochemical and immunoelectron microscopy analyses of various populations of post-Golgi vesicles immunopurified with magnetic beads led us to identify post-Golgi transport vesicles containing both rapsyn and AChR. These data suggest that rapsyn, as for AChR, specifically follows the exocytic pathway. Furthermore, immunogold-labeling experiments provided in situ evidence that AChR and rapsyn are cotransported in the same post-Golgi vesicles. Taken together, our observations suggest that rapsyn and AChR are cotargeted to the Postsynaptic Membrane. [1]: #ref-7
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AnkyrinG is associated with the Postsynaptic Membrane and the sarcoplasmic reticulum in the skeletal muscle fiber
Journal of Cell Science, 1998Co-Authors: Ekaterini Kordeli, Marie Aline Ludosky, Christiane Deprette, Thierry Frappier, Jean CartaudAbstract:Ankyrins are a multi-gene family of peripheral proteins that link ion channels and cell adhesion molecules to the spectrin-based skeleton in specialized Membrane domains. In the mammalian skeletal myofiber, ankyrins were immunolocalized in several Membrane domains, namely the costameres, the Postsynaptic Membrane and the triads. Ank1 and Ank3 transcripts were previously detected in skeletal muscle by northern blot analysis. However, the ankyrin isoforms associated with these domains were not identified, with the exception of an unconventional Ank1 gene product that was recently localized at discrete sites of the sarcoplasmic reticulum. Here we study the expression and subcellular distribution of the Ank3 gene products, the ankyrinsG, in the rat skeletal muscle fiber. Northern blot analysis of rat skeletal muscle mRNAs using domain-specific Ank3 cDNA probes revealed two transcripts of 8.0 kb and 5.6 kb containing the spectrin-binding and C-terminal, but not the serine-rich, domains. Reverse transcriptase PCR analysis of rat skeletal muscle total RNA confirmed the presence of Ank3 transcripts that lacked the serine-rich and tail domains, a major insert of 7813 bp at the junction of the spectrin-binding and C-terminal domains that was previously identified in brain Ank3 transcripts. Immunoblot analysis of total skeletal muscle homogenates using ankyrinG-specific antibodies revealed one major 100 kDa ankyrinG polypeptide. Immunofluorescence labeling of rat diaphragm cryosections showed that ankyrin(s)G are selectively associated with (1) the depths of the Postsynaptic Membrane folds, where the voltage-dependent sodium channel and N-CAM accumulate, and (2) the sarcoplasmic reticulum, as confirmed by codistribution with the sarcoplasmic reticulum Ca2+-ATPase (SERCA 1). At variance with ankyrin(s)G, ankyrin(s)R (ank1 gene products) accumulate at the sarcolemma and at sarcoplasmic structures, in register with A-bands. Both ankyrin isoforms codistributed over Z-lines and at the Postsynaptic Membrane. These data extend the notion that ankyrins are differentially localized within myofibers, and point to a role of the ankyrinG family in the organization of the sarcoplasmic reticulum and the Postsynaptic Membrane.
Ming Tian - One of the best experts on this subject based on the ideXlab platform.
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changes in expression of neuroligin1 in excitatory Postsynaptic Membrane of spinal dorsal horn in a rat model of incisional pain
Chinese Journal of Anesthesiology, 2017Co-Authors: Ruijuan Guo, Zhaojing Xue, Yun Wang, Ming TianAbstract:Objective To evaluate the changes in the expression of neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn in a rat model of incisional pain. Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 280-320 g, were divided into control group(group C, n=12)and incisional pain group(group I, n=36)using a random number table.A 1 cm long incision was made in the plantar surface of the right hindpaw in group I. Cumulative pain score(CPS)was assessed and mechanical paw withdrawal threshold to von Frey stimuli was measured at 3 h and 1 and 3 days after operation(T1, 2, 3). The animals were then sacrificed and their lumbar segments(L3-6)of the spinal cord were removed for detection of the expression of neuroligin1, Postsynaptic density-95 protein(PSD-95), glutamate receptor 1(GluR1)and GluR2 in the Postsynaptic Membrane of spinal dorsal horn(by Western blot)and co-expression of neuroligin1 with PSD-95 in spinal dorsal horn(by co-immuno-precipitation). Results Compared with group C, CPS was significantly increased and mechanical paw withdrawal threshold was decreased at T1-3, and the expression of neuroligin1 and GluR1 in the Postsynaptic Membrane of spinal dorsal horn at T1, 2 and co-expression of neuroligin1 with PSD-95 at T1 were up-regulated in group I(P<0.01 or 0.05). Conclusion The development and maintenance of incisional pain is related to the signaling pathway regulated by neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn of rats. Key words: Cell Adhesion Molecules; Pain; Spinal cord; Receptors, AMPA
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Changes in expression of neuroligin1 in excitatory Postsynaptic Membrane of spinal dorsal horn in a rat model of incisional pain
Chinese Journal of Anesthesiology, 2017Co-Authors: Ruijuan Guo, Zhaojing Xue, Yun Wang, Ming TianAbstract:Objective To evaluate the changes in the expression of neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn in a rat model of incisional pain. Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 280-320 g, were divided into control group(group C, n=12)and incisional pain group(group I, n=36)using a random number table.A 1 cm long incision was made in the plantar surface of the right hindpaw in group I. Cumulative pain score(CPS)was assessed and mechanical paw withdrawal threshold to von Frey stimuli was measured at 3 h and 1 and 3 days after operation(T1, 2, 3). The animals were then sacrificed and their lumbar segments(L3-6)of the spinal cord were removed for detection of the expression of neuroligin1, Postsynaptic density-95 protein(PSD-95), glutamate receptor 1(GluR1)and GluR2 in the Postsynaptic Membrane of spinal dorsal horn(by Western blot)and co-expression of neuroligin1 with PSD-95 in spinal dorsal horn(by co-immuno-precipitation). Results Compared with group C, CPS was significantly increased and mechanical paw withdrawal threshold was decreased at T1-3, and the expression of neuroligin1 and GluR1 in the Postsynaptic Membrane of spinal dorsal horn at T1, 2 and co-expression of neuroligin1 with PSD-95 at T1 were up-regulated in group I(P
Joachim Kirsch - One of the best experts on this subject based on the ideXlab platform.
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Molecular architecture of glycinergic synapses
Histochemistry and Cell Biology, 2008Co-Authors: Thomas Dresbach, Jochen Kuhse, Ralph Nawrotzki, Thomas Kremer, Stefanie Schumacher, Daniel Quinones, Martin Kluska, Joachim KirschAbstract:Synapses can be considered chemical machines, which are optimized for fast and repeated exocytosis of neurotransmitters from presynaptic nerve terminals and the reliable electrical or chemical transduction of neurotransmitter binding to the appropriate receptors in the Postsynaptic Membrane. Therefore, synapses share a common repertoire of proteins like, e.g., the release machinery and certain cell adhesion molecules. This basic repertoire must be extended in order to generate specificity of neurotransmission and allow plastic changes, which are considered the basis of developmental and/or learning processes. Here, we focus on these complementary molecules located in the presynaptic terminal and Postsynaptic Membrane specializations of glycinergic synapses. Moreover, as specificity of neurotransmission in this system is established by the specific binding of the neurotransmitter to its receptor, we review the molecular properties of glycine receptor subunits and their assembly into functional glycine receptors with different functional characteristics. The past years have revealed that the molecular machinery underlying inhibitory and especially glycinergic Postsynaptic Membrane specializations is more complex and dynamic than previously anticipated from morphological studies. The emerging features include structural components as well as signaling modules, which could confer the plasticity required for the proper function of distinct motor and sensory functions.
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Assembly of signaling machinery at the Postsynaptic Membrane.
Current opinion in neurobiology, 1999Co-Authors: Joachim KirschAbstract:The Postsynaptic Membrane and the subsynaptic cell compartment are specialized for inter- and intracellular signaling. Recent work has focused on the role of synaptic activity in regulating the surface distribution of neurotransmitter receptors. In addition, several components of secondary signaling pathways involved in the long-term regulation of synaptic efficacy have been identified.
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molecular mechanisms that underlie structural and functional changes at the Postsynaptic Membrane during synaptic plasticity
Progress in Neurobiology, 1998Co-Authors: H V Wheal, Melitta Schachner, Ying Chen, J Mitchell, W Maerz, H Wieland, D Van Rossum, Joachim KirschAbstract:The synaptic plasticity that is addressed in this review follows neurodegeneration in the brain and thus has both structural as well as functional components. The model of neurodegeneration that has been selected is the kainic acid lesioned hippocampus. Degeneration of the CA3 pyramidal cells results in a loss of the Schaffer collateral afferents innervating the CA1 pyramidal cells. This is followed by a period of structural plasticity where new synapses are formed. These are associated with changes in the numbers and shapes of spines as well as changes in the morphometry of the dendrites. It is suggested that this synaptogenesis is responsible for an increase in the ratio of NMDA to AMPA receptors mediating excitatory synaptic transmission at these synapses. Changes in the temporal and spatial properties of these synapses resulted in an altered balance between LTP and LTD. These properties together with a reduction in the inhibitory drive increased the excitability of the surviving CA1 pyramidal cells which in turn triggered epileptiform bursting activity. In this review we discuss the insights that may be gained from studies of the underlying molecular machinery. Developments in one of the collections of the cogs in this machinery has been summarized through recent studies characterizing the roles of neural recognition molecules in synaptic plasticity in the adult nervous systems of vertebrates and invertebrates. Such investigations of neural cell adhesion molecules, cadherins and amyloid precursor protein have shown the involvement of these molecules on the morphogenetic level of synaptic changes, on the one hand, and signal transduction effects, on the other. Further complex cogs are found in the forms of the low-density lipoprotein receptor (LDL-R) family of genes and their ligands play pivotal roles in the brain development and in regulating the growth and remodelling of neurones. Evidence is discussed for their role in the maintenance of cognitive function as well as Alzheimer's. The molecular mechanisms responsible for the clustering and maintenance of transmitter receptors at Postsynaptic sites are the final cogs in the machinery that we have reviewed. Postsynaptic densities (PSD) from excitatory synapses have yielded many cytoskeletal proteins including actin, spectrin, tubulin, microtubule-associated proteins and calcium/calmodulin-dependent protein kinase II. Isolated PSDs have also been shown to be enriched in AMPA, kainate and NMDA receptors. However, recently, a new family of proteins, the MAGUKs (for Membrane-associated guanylate kinase) has emerged. The role of these proteins in clustering different NMDA receptor subunits is discussed. The MAGUK proteins are also thought to play a role in synaptic plasticity mediated by nitric oxide (NO). Both NMDA and non-NMDA receptors are highly clustered at excitatory Postsynaptic sites in cortical and hippocampal neurones but have revealed differences in their choice of molecular components. Both GABAA and glycine (Gly) receptors mediate synaptic inhibition in the brain and spinal cord. Whilst little is known about how GABAA receptors are localized in the Postsynaptic Membrane, considerable progress has been made towards the elucidation of the molecular mechanisms underlying the formation of Gly receptors. It has been shown that the peripheral Membrane protein gephyrin plays a pivotal role in the formation of Gly receptor clusters most likely by anchoring the receptor to the subsynaptic cytoskeleton. Evidence for the distribution as well as function of gephyrin and Gly receptors is discussed. Postsynaptic Membrane specializations are complex molecular machinery subserving a multitude of functions in the proper communication between neurones. Despite the fact that only a few key players have been identified it will be a fascinating to watch the story as to how they contribute to structural and functional plasticity unfold.
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■ REVIEW : Postsynaptic Anchoring of Receptors: A Cellular Approach to Neuronal and Muscular Sensitivity
The Neuroscientist, 1996Co-Authors: Joachim Kirsch, Stephan KrögerAbstract:Significant progress has been made toward the elucidation of the molecular mechanisms underlying the biogenesis and stabilization of Postsynaptic Membrane specializations at the neuromuscular junction of vertebrate skeletal muscle. The emerging picture reveals a continuous molecular link from the extracellular matrix within the synaptic cleft via integral and peripheral Membrane proteins to the subsarcolemmal cytoskeleton. The formation and maintenance of synaptic contacts between neurons in the CNS might follow similar architectural principles but involve different molecules. The biogenesis of glycinergic Postsynaptic Membrane specializations depends on the widely expressed peripheral Membrane protein gephyrin, which anchors the neurotransmitter receptor to underlying cytoskeletal elements in a dynamic manner. This anchoring mechanism could also contribute to the plasticity of glycinergic synapses. Other types of neurotransmitter receptors, like GABAA- and glutamate receptors, may have evolved different ...
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How to build a glycinergic Postsynaptic Membrane.
Journal of cell science. Supplement, 1991Co-Authors: Heinrich Betz, Jochen Kuhse, Volker Schmieden, Maria Luisa Malosio, Dieter Langosch, Peter Prior, Bertram Schmitt, Joachim KirschAbstract:Summary The inhibitory glycine receptor (GlyR) is a ligand-gated chloride channel protein found at many synapses of the mammalian central nervous system. During development, distinct isoforms of the GlyR are generated by the sequential expression of different α subunit variants. The appearance of adult-type GlyRs in spinal cord is accompanied by the accumulation of a 93×10 3 M r , receptor-associated peripheral Membrane protein. The latter has been localized at the cytoplasmic face of glycinergic Postsynaptic Membranes and is thought to anchor GlyRs beneath glycinergic nerve terminals. The 93×10 3 M r protein binds with high affinity to polymerized tubulin, suggesting that it functions as a receptor–microtubule linking component. Our data suggest that the interaction of developmentally regulated receptor isoforms with specialized microtubule–associated proteins represents a crucial step in the assembly of Postsynaptic receptor matrices.
Ruijuan Guo - One of the best experts on this subject based on the ideXlab platform.
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changes in expression of neuroligin1 in excitatory Postsynaptic Membrane of spinal dorsal horn in a rat model of incisional pain
Chinese Journal of Anesthesiology, 2017Co-Authors: Ruijuan Guo, Zhaojing Xue, Yun Wang, Ming TianAbstract:Objective To evaluate the changes in the expression of neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn in a rat model of incisional pain. Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 280-320 g, were divided into control group(group C, n=12)and incisional pain group(group I, n=36)using a random number table.A 1 cm long incision was made in the plantar surface of the right hindpaw in group I. Cumulative pain score(CPS)was assessed and mechanical paw withdrawal threshold to von Frey stimuli was measured at 3 h and 1 and 3 days after operation(T1, 2, 3). The animals were then sacrificed and their lumbar segments(L3-6)of the spinal cord were removed for detection of the expression of neuroligin1, Postsynaptic density-95 protein(PSD-95), glutamate receptor 1(GluR1)and GluR2 in the Postsynaptic Membrane of spinal dorsal horn(by Western blot)and co-expression of neuroligin1 with PSD-95 in spinal dorsal horn(by co-immuno-precipitation). Results Compared with group C, CPS was significantly increased and mechanical paw withdrawal threshold was decreased at T1-3, and the expression of neuroligin1 and GluR1 in the Postsynaptic Membrane of spinal dorsal horn at T1, 2 and co-expression of neuroligin1 with PSD-95 at T1 were up-regulated in group I(P<0.01 or 0.05). Conclusion The development and maintenance of incisional pain is related to the signaling pathway regulated by neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn of rats. Key words: Cell Adhesion Molecules; Pain; Spinal cord; Receptors, AMPA
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Changes in expression of neuroligin1 in excitatory Postsynaptic Membrane of spinal dorsal horn in a rat model of incisional pain
Chinese Journal of Anesthesiology, 2017Co-Authors: Ruijuan Guo, Zhaojing Xue, Yun Wang, Ming TianAbstract:Objective To evaluate the changes in the expression of neuroligin1 in excitatory Postsynaptic Membrane of the spinal dorsal horn in a rat model of incisional pain. Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 280-320 g, were divided into control group(group C, n=12)and incisional pain group(group I, n=36)using a random number table.A 1 cm long incision was made in the plantar surface of the right hindpaw in group I. Cumulative pain score(CPS)was assessed and mechanical paw withdrawal threshold to von Frey stimuli was measured at 3 h and 1 and 3 days after operation(T1, 2, 3). The animals were then sacrificed and their lumbar segments(L3-6)of the spinal cord were removed for detection of the expression of neuroligin1, Postsynaptic density-95 protein(PSD-95), glutamate receptor 1(GluR1)and GluR2 in the Postsynaptic Membrane of spinal dorsal horn(by Western blot)and co-expression of neuroligin1 with PSD-95 in spinal dorsal horn(by co-immuno-precipitation). Results Compared with group C, CPS was significantly increased and mechanical paw withdrawal threshold was decreased at T1-3, and the expression of neuroligin1 and GluR1 in the Postsynaptic Membrane of spinal dorsal horn at T1, 2 and co-expression of neuroligin1 with PSD-95 at T1 were up-regulated in group I(P
J Cartaud - One of the best experts on this subject based on the ideXlab platform.
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Targeting of acetylcholine receptor and 43 kDa rapsyn to the Postsynaptic Membrane in Torpedo marmorata electrocyte.
Journal of physiology Paris, 1998Co-Authors: F Bignami, Gilles Camus, S Marchand, L Bailly, F Stetzkowski-marden, J CartaudAbstract:In this study we have investigated the intracellular routing of two major components of the Postsynaptic Membrane in Torpedo electrocytes, the nicotinic acetylcholine receptor and the extrinsic 43 kDa protein rapsyn, and of a protein from the non-innervated Membrane, the Na+,K+ ATPase. We isolated subpopulations of post-Golgi vesicles (PGVs) enriched either in AChR or in Na+,K+ ATPase. Rapsyn was associated to AChR-containing PGVs suggesting that both AChR and rapsyn are targeted to intracellular organelles in the secretory pathway before delivery to the Postsynaptic Membrane. In vitro assays further show that rapsyn-containing PVGs do bind more efficiently to microtubules compared to Na+,K+ ATPase-enriched PVGs. These data provide evidence in favor of the contribution of the secretory pathway to the delivery of synaptic components.
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Direct involvement of a lamin-B-related (54 kDa) protein in the association of intermediate filaments with the Postsynaptic Membrane of the Torpedo marmorata electrocyte.
Journal of cell science, 1995Co-Authors: Annie Cartaud, B J Jasmin, J P Changeux, J CartaudAbstract:Mechanisms by which motor innervation induces Postsynaptic Membrane differentiation and functional compartmentalization of the subneural sarcoplasm in skeletal muscle fibres are still poorly understood. However, transMembrane control of cytoskeletal activities by the nerve terminal may be considered. Here, we examine several properties of a 54 kDa protein, previously identified in the Postsynaptic Membrane of the Torpedo marmorata electrocyte with anti-lamin B antibodies, in order to study its role in the assembly of the subneural intermediate filament meshwork. Using a ligand blot assay, we show that this protein binds desmin, a type III intermediate filaments protein, at micromolar concentrations. Moreover, purified acetylcholine receptor-rich Membrane fragments are able to generate arrays of desmin filaments in vitro. Immunofluorescence experiments indicate that the 54 kDa protein becomes associated with the acetylcholine receptor-rich Membrane at an early stage of development of the electrocyte, and that a polarized desmin network develops concomitantly from the Postsynaptic Membrane. Taken together, these data show that, like karyoskeletal lamin B, the 54 kDa protein is involved in the organization of the subneural intermediate filament meshwork. Control of the assembly of the subneural cytoskeleton by components of the Postsynaptic Membrane may thus be a prerequisite for the functional compartmentalization of the muscle fibre triggered by motor innervation.