We used a novel mammalian coculture system to study ACh receptor (AChR) redistribution and synaptic structure at nerve-muscle contacts. Ventral spinal cord (VSC) neurons were plated on cultures containing extensive myotubes but few fibroblasts. Neurite-induced redistribution of AChRs occurred within 6 hr after plating neurons and was maximal between 36-48 ... More
Signaling by insulin-like growth factors in paralyzed skeletal muscle: rapid induction of IGF1 expression in muscle fibers and prevention of interstitial cell proliferation by IGF-BP5 and IGF-BP4.
AuthorsCaroni P, Schneider C
JournalJ Neurosci
PubMed ID7514217
'In the absence of muscle activity, muscle fibers, muscle interstitial cells, and intramuscular nerves display characteristic reactions presumably aimed at restoring a functioning neuromuscular system and avoiding degenerative events. In partially denervated muscle these include proliferation of interstitial cells, followed by nerve sprouting. The same reactions can be induced in ... More
Identification of nicotinic acetylcholine receptor recycling and its role in maintaining receptor density at the neuromuscular junction in vivo.
AuthorsBruneau E, Sutter D, Hume RI, Akaaboune M
JournalJ Neurosci
PubMed ID16251443
'In the CNS, receptor recycling is critical for synaptic plasticity; however, the recycling of receptors has never been observed at peripheral synapses. Using a novel imaging technique, we show here that nicotinic acetylcholine receptors (AChRs) recycle into the postsynaptic membrane of the neuromuscular junction. By sequentially labeling AChRs with biotin-bungarotoxin ... More
The dystroglycan complex is necessary for stabilization of acetylcholine receptor clusters at neuromuscular junctions and formation of the synaptic basement membrane.
AuthorsJacobson C, Côté PD, Rossi SG, Rotundo RL, Carbonetto S
JournalJ Cell Biol
PubMed ID11157973
'The dystrophin-associated protein (DAP) complex spans the sarcolemmal membrane linking the cytoskeleton to the basement membrane surrounding each myofiber. Defects in the DAP complex have been linked previously to a variety of muscular dystrophies. Other evidence points to a role for the DAP complex in formation of nerve-muscle synapses. We ... More
Long-term maintenance of presynaptic function in the absence of target muscle fibers.
AuthorsDunaevsky A, Connor EA
JournalJ Neurosci
PubMed ID7666196
'Here we have investigated the role of the muscle fiber in the maintenance of presynaptic function at frog motor nerve terminals. Muscle fibers were selectively damaged and prevented from regenerating while leaving the motor innervation intact. Presynaptic activity of the resulting target-deprived nerve terminals was assayed using the fluorescent dye, ... More
Imaging of receptor trafficking by using alpha-bungarotoxin-binding-site-tagged receptors.
AuthorsSekine-Aizawa Y, Huganir RL,
JournalProc Natl Acad Sci U S A
PubMed ID15563595
'alpha-Amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors mediate excitatory synaptic transmission and are dynamically regulated during synaptic plasticity in the CNS. The membrane trafficking of AMPA receptors to synapses is critical for the regulation of the efficacy of excitatory synaptic transmission. Direct imaging of AMPA receptors in various cell compartments is important to dissecting ... More
Acetylcholine receptor in a C2 muscle cell variant is retained in the endoplasmic reticulum.
AuthorsGu Y, Ralston E, Murphy-Erdosh C, Black RA, Hall ZW
JournalJ Cell Biol
PubMed ID2668304
'We have examined the properties and intracellular localization of acetylcholine receptors in the C2 muscle cell line and in a variant (T-) that accumulates AChR intracellularly. On immunoblots, the subunit structures of the AChR from wild-type and T- cells were similar except that the gamma and delta subunits of the ... More
Motor axon guidance of the mammalian trochlear and phrenic nerves: dependence on the netrin receptor Unc5c and modifier loci.
AuthorsBurgess RW, Jucius TJ, Ackerman SL
JournalJ Neurosci
PubMed ID16723533
'Netrin signaling is important to guide migrating neurons and axons in many systems. Experiments with vertebrate CNS explants suggested netrin is bifunctional, attracting some axons and repelling others. Netrin1-expressing cells attracted spinal commissural axons and repelled trochlear cranial nerve axons in these experiments. Subsequent genetic studies demonstrated that multiple axon ... More
Subtle neuromuscular defects in utrophin-deficient mice.
AuthorsGrady RM, Merlie JP, Sanes JR
JournalJ Cell Biol
PubMed ID9049252
'Utrophin is a large cytoskeletal protein that is homologous to dystrophin, the protein mutated in Duchenne and Becker muscular dystrophy. In skeletal muscle, dystrophin is broadly distributed along the sarcolemma whereas utrophin is concentrated at the neuromuscular junction. This differential localization, along with studies on cultured cells, led to the ... More
alpha-Bungarotoxin binding sites in rat hippocampal and cortical cultures: initial characterisation, colocalisation with alpha 7 subunits and up-regulation by chronic nicotine treatment.
AuthorsBarrantes GE, Rogers AT, Lindstrom J, Wonnacott S
JournalBrain Res
PubMed ID7749744
'High density neuronal cultures from rat E18 hippocampus and cortex have been characterised with respect to cholinergic binding sites. No specific binding of [3H]nicotine or [3H]cytisine to live cells in situ was detected although the limit for detection was estimated to be 30 fmol/mg protein. Muscarinic binding sites labelled with ... More
Transplantation of quail collagen-tailed acetylcholinesterase molecules onto the frog neuromuscular synapse.
AuthorsRotundo RL, Rossi SG, Anglister L
JournalJ Cell Biol
PubMed ID9015307
'The highly organized pattern of acetylcholinesterase (AChE) molecules attached to the basal lamina of the neuromuscular junction (NMJ) suggests the existence of specific binding sites for their precise localization. To test this hypothesis we immunoaffinity purified quail globular and collagen-tailed AChE forms and determined their ability to attach to frog ... More
An unusual beta-spectrin associated with clustered acetylcholine receptors.
AuthorsBloch RJ, Morrow JS
JournalJ Cell Biol
PubMed ID2645300
'The clustering of acetylcholine receptors (AChR) in the postsynaptic membrane is an early event in the formation of the neuromuscular junction. The mechanism of clustering is still unknown, but is generally believed to be mediated by the postsynaptic cytoskeleton. We have identified an unusual isoform of beta-spectrin which colocalizes with ... More
Receptor (CD155)-dependent endocytosis of poliovirus and retrograde axonal transport of the endosome.
AuthorsOhka S, Matsuda N, Tohyama K, Oda T, Morikawa M, Kuge S, Nomoto A
JournalJ Virol
PubMed ID15194795
'Poliovirus (PV), when injected intramuscularly into the calf, is incorporated into the sciatic nerve and causes an initial paralysis of the inoculated limb in transgenic mice carrying the human PV receptor (hPVR/CD155) gene. Here, we demonstrated by using an immunoelectron microscope that PV particles exist on vesicle structures in nerve ... More
Agrin is a heparan sulfate proteoglycan.
AuthorsTsen G, Halfter W, Kröger S, Cole GJ
JournalJ Biol Chem
PubMed ID7852425
'In the present study we have identified the extracellular matrix protein agrin as a major heparan sulfate proteoglycan (HSPG) in embryonic chick brain. Using monoclonal antibodies and a polyclonal antiserum to the core protein of a previously identified HSPG from embryonic chick brain, our expression screened a random-primed E9 chick ... More
A role of tyrosine phosphorylation in the formation of acetylcholine receptor clusters induced by electric fields in cultured Xenopus muscle cells.
AuthorsPeng HB, Baker LP, Dai Z
JournalJ Cell Biol
PubMed ID7678012
'During the development of the neuromuscular junction, acetylcholine receptors (AChRs) become clustered in the postsynaptic membrane in response to innervation. In vitro, several non-neuronal stimuli can also induce the formation of AChR clusters. DC electric field (E field) is one of them. When cultured Xenopus muscle cells are exposed to ... More
Presynaptic localization of sodium/calcium exchangers in neuromuscular preparations.
'Calcium ions play a critical role in neurotransmitter release. The cytosolic Ca2+ concentration ([Ca2+]cyt) at nerve terminals must therefore be carefully controlled. Several different mechanisms, including a plasmalemmal Na/Ca exchanger, are involved in regulating [Ca2+]cyt. We employed immunofluorescence microscopy with polyclonal antiserum raised against dog cardiac sarcolemmal Na/Ca exchanger to ... More
Differentiation of muscle, fat, cartilage, and bone from progenitor cells present in a bone-derived clonal cell population: effect of dexamethasone.
AuthorsGrigoriadis AE, Heersche JN, Aubin JE
JournalJ Cell Biol
PubMed ID3384856
'RCJ 3.1, a clonally derived cell population isolated from 21-d fetal rat calvaria, expresses the osteoblast-associated characteristics of polygonal morphology, a cAMP response to parathyroid hormone, synthesis of predominantly type I collagen, and the presence of 1,25-dihydroxyvitamin D3-regulated alkaline phosphatase activity. When cultured in the presence of ascorbic acid, sodium ... More
The role of lateral migration in the formation of acetylcholine receptor clusters induced by basic polypeptide-coated latex beads.
AuthorsPeng HB, Zhao DY, Xie MZ, Shen ZW, Jacobson K
JournalDev Biol
PubMed ID2909404
'During the formation of the neuromuscular junction, the nerve induces the clustering of acetylcholine receptors (AChR) in the postsynaptic membrane. This process can be mimicked by treating cultured Xenopus myotomal muscle cells with basic polypeptide-coated latex beads. Using this bead-muscle coculture system, we examined the role of lateral migration of ... More
Sodium channels aggregate at former synaptic sites in innervated and denervated regenerating muscles.
AuthorsLupa MT, Caldwell JH
JournalJ Cell Biol
PubMed ID8294497
'The role of innervation in the establishment and regulation of the synaptic density of voltage-activated Na channels (NaChs) was investigated at regenerating neuromuscular junctions. Rat muscles were induced to degenerate after injection of the Australian tiger snake toxin, notexin. The loose-patch voltage clamp technique was used to measure the density ... More
Acetylcholine receptor aggregation parallels the deposition of a basal lamina proteoglycan during development of the neuromuscular junction.
AuthorsAnderson MJ, Klier FG, Tanguay KE
JournalJ Cell Biol
PubMed ID6386827
'To determine the time course of synaptic differentiation, we made successive observations on identified, nerve-contacted muscle cells developing in culture. The cultures had either been stained with fluorescent alpha-bungarotoxin, or were maintained in the presence of a fluorescent monoclonal antibody. These probes are directed at acetylcholine receptors (AChR) and a ... More
Aberrant motor axon projection, acetylcholine receptor clustering, and neurotransmission in cyclin-dependent kinase 5 null mice.
AuthorsFu AK, Ip FC, Fu WY, Cheung J, Wang JH, Yung WH, Ip NY
JournalProc Natl Acad Sci U S A
PubMed ID16203963
'Cyclin-dependent kinase (Cdk)5 is a key regulator of neural development. We have previously demonstrated that Cdk5/p35 are localized to the postsynaptic muscle and are implicated in the regulation of neuregulin/ErbB signaling in myotube culture. To further elucidate whether Cdk5 activity contributes to neuromuscular junction (NMJ) development in vivo, the NMJ ... More
A functional role for specific spliced variants of the alpha7beta1 integrin in acetylcholine receptor clustering.
AuthorsBurkin DJ, Gu M, Hodges BL, Campanelli JT, Kaufman SJ
JournalJ Cell Biol
PubMed ID9817762
'The clustering of acetylcholine receptors (AChR) on skeletal muscle fibers is an early event in the formation of neuromuscular junctions. Recent studies show that laminin as well as agrin can induce AChR clustering. Since the alpha7beta1 integrin is a major laminin receptor in skeletal muscle, we determined if this integrin ... More
Variation among acetylcholine receptor clusters induced by ciliary ganglion neurons in vitro.
AuthorsDubinsky JM, Morgan M, Fischbach GD
JournalDev Biol
PubMed ID2846386
'We have examined the variation in receptor density and area among neurite-associated acetylcholine receptor patches (NARPs) induced by chick ciliary ganglion neurons on nearby myotubes in vitro. Quantitative analysis of rhodamine-alpha-bungarotoxin (RBTX) NARPs revealed that about 15% of the NARPs were "outstanding" in terms of size (greater than 60 micron ... More
Vitronectin at sites of cell-substrate contact in cultures of rat myotubes.
AuthorsBaetscher M, Pumplin DW, Bloch RJ
JournalJ Cell Biol
PubMed ID2426279
'Affinity-purified antibodies to the serum glycoprotein, vitronectin, were used to study sites of cell-substrate contact in cultures of rat myotubes and fibroblasts. Cells were removed from the substrate by treatment with saponin, leaving fragments of plasma membrane attached to the glass coverslip. When stained for vitronectin by indirect immunofluorescence, large ... More
Developmental and neural regulation of a subsarcolemmal component of the rat neuromuscular junction.
AuthorsAstrow SH, Sutton LA, Thompson WJ
JournalJ Neurosci
PubMed ID1374459
'We have generated a monoclonal antibody, designated mAb 3G2, which reacts with a subsarcolemmal component of the neuromuscular junction in adult rats. mAb 3G2 immunoreactivity lies beneath and between the ACh receptor-rich synaptic gutters, around the sole plate nuclei, and at/near sarcomeric Z-disks in the vicinity of the synapse. Localization ... More
Formation of acetylcholine receptor clusters in chick myotubes: migration or new insertion?
AuthorsDubinsky JM, Loftus DJ, Fischbach GD, Elson EL
JournalJ Cell Biol
PubMed ID2793937
'Experiments were performed to study the feasibility of two mechanisms of acetylcholine receptor (ACHR) accumulation in chick myotubes: diffusion and trapping of previously dispersed surface receptors and localized insertion of new receptors at accumulation sites. Fluorescence photobleaching recovery (FPR) measurements indicated that the majority of diffusely distributed ACHRs in chick ... More
Vinculin in subsarcolemmal densities in chicken skeletal muscle: localization and relationship to intracellular and extracellular structures.
AuthorsShear CR, Bloch RJ
JournalJ Cell Biol
PubMed ID3924918
'Using immunocytochemical methods we have studied the distribution of vinculin in the anterior and posterior latissimus dorsi skeletal (ALD and PLD, respectively) muscles of the adult chicken. The ALD muscle is made up of both tonic (85%) and twitch (15%) myofibers, and the PLD muscle is made up entirely of ... More
An extracellular pathway for dystroglycan function in acetylcholine receptor aggregation and laminin deposition in skeletal myotubes.
AuthorsTremblay MR, Carbonetto S
JournalJ Biol Chem
PubMed ID16531403
'The dystroglycan (DG) complex is involved in agrin-induced acetylcholine receptor clustering downstream of muscle-specific kinase where it regulates the stability of acetylcholine receptor aggregates as well as assembly of the synaptic basement membrane. We have previously proposed that this entails coordinate extracellular and intracellular interactions of its two subunits, alpha- ... More
Distribution of N-CAM in synaptic and extrasynaptic portions of developing and adult skeletal muscle.
AuthorsCovault J, Sanes JR
JournalJ Cell Biol
PubMed ID3512581
'Previous studies of denervated and cultured muscle have shown that the expression of the neural cell adhesion molecule (N-CAM) in muscle is regulated by the muscle's state of innervation and that N-CAM might mediate some developmentally important nerve-muscle interactions. As a first step in learning whether N-CAM might regulate or ... More
Membrane tethering enables an extracellular domain of the acetylcholine receptor alpha subunit to form a heterodimeric ligand-binding site.
AuthorsWang ZZ, Hardy SF, Hall ZW
JournalJ Cell Biol
PubMed ID8909552
'The first step of assembly of the nicotinic acetylcholine receptor (AChR) of adult skeletal muscle is the specific association of the alpha subunit with either delta or epsilon subunits to form a heterodimer with a ligand-binding site. Previous experiments have suggested that het erodimer formation in the ER arises from ... More
Evidence for a polarity in the distribution of proteins from the cytoskeleton in Torpedo marmorata electrocytes.
'The subcellular distribution of the 43,000-D protein (43 kD or v1) and of some major cytoskeletal proteins was investigated in Torpedo marmorata electrocytes by immunocytochemical methods (immunofluorescence and immunogold at the electron microscope level) on frozen-fixed sections and homogenates of electric tissue. A monoclonal antibody directed against the 43-kD protein ... More
In vivo observations of pre- and postsynaptic changes during the transition from multiple to single innervation at developing neuromuscular junctions.
AuthorsBalice-Gordon RJ, Lichtman JW
JournalJ Neurosci
PubMed ID8426240
'Synaptic rearrangements in developing muscle were studied by visualizing individual neuromuscular junctions in the sternomastoid muscle of living neonatal mice as they underwent the transition from multiple to single innervation. Vital staining of ACh receptors (AChRs) with rhodamine-conjugated alpha-bungarotoxin showed that while junctions were still multiply innervated (usually by two ... More
Cytoplasmic components of acetylcholine receptor clusters of cultured rat myotubes: the 58-kD protein.
AuthorsBloch RJ, Resneck WG, O'Neill A, Strong J, Pumplin DW
JournalJ Cell Biol
PubMed ID1918149
'A 58-kD protein, identified in extracts of postsynaptic membrane from Torpedo electric organ, is enriched at sites where acetylcholine receptors (AChR) are concentrated in vertebrate muscle (Froehner, S. C., A. A. Murnane, M. Tobler, H. B. Peng, and R. Sealock. 1987. J. Cell Biol. 104:1633-1646). We have studied the 58-kD ... More
Cell surface acetylcholinesterase molecules on multinucleated myotubes are clustered over the nucleus of origin.
AuthorsRossi SG, Rotundo RL
JournalJ Cell Biol
PubMed ID1469054
'Multinucleated skeletal muscle fibers are compartmentalized with respect to the expression and organization of several intracellular and cell surface proteins including acetylcholinesterase (AChE). Mosaic muscle fibers formed from homozygous myoblasts expressing two allelic variants of AChE preferentially translate and assemble the polypeptides in the vicinity of the nucleus encoding the ... More
Vital imaging and ultrastructural analysis of individual axon terminals labeled by iontophoretic application of lipophilic dye.
AuthorsGan WB, Bishop DL, Turney SG, Lichtman JW
JournalJ Neurosci Methods
PubMed ID10598860
'We describe a method for in vivo confocal fluorescence imaging of synaptic terminals and subsequent electron microscopic reconstructions of the same terminals. By iontophoretically applying lipophilic dye to nerve terminals at a single neuromuscular junction with a sharp microelectrode in living neonatal mice, we were able to quickly label other ... More
Agrin-deficient myotube retains its acetylcholine receptor aggregation ability when challenged with agrin.
AuthorsPun S, Ng YP, Yang JF, Ip NY, Tsim KW
JournalJ Neurochem
PubMed ID9375689
'Agrin is a synapse-organizing molecule that mediates the nerve-induced aggregation of acetylcholine receptors (AChRs) and other postsynaptic components at the developing and regenerating vertebrate neuromuscular junctions. At the neuromuscular junction, three different cell types can express agrin, i.e., neuron, muscle, and Schwann cell. Several lines of evidence suggested that neuron-derived ... More
Role of the cytoskeleton in the formation, stabilization, and removal of acetylcholine receptor clusters in cultured muscle cells.
AuthorsConnolly JA
JournalJ Cell Biol
PubMed ID6539781
'We have examined the effects of microtubule- and microfilament-disrupting drugs on the stability, formation, and removal of acetylcholine (ACh) receptors and ACh receptor clusters on the surface of aneurally cultured chick embryonic myotubes. (a) In muscle cell cultures, cytochalasin D (0.2 microgram/ml) or B (2.0 micrograms/ml) causes the dispersal of ... More
'Agrin is an extracellular matrix protein that directs neuromuscular junction formation. Early signal transduction events in agrin-mediated postsynaptic differentiation include activation of a receptor tyrosine kinase and phosphorylation of acetylcholine receptors (AChRs), but later steps in this pathway are unknown. Here, we have investigated the role of intracellular calcium in ... More
Motor neurons contain agrin-like molecules.
AuthorsMagill-Solc C, McMahan UJ
JournalJ Cell Biol
PubMed ID2846587
'Molecules antigenically similar to agrin, a protein extracted from the electric organ of Torpedo californica, are highly concentrated in the synaptic basal lamina of neuromuscular junctions in vertebrate skeletal muscle. On the basis of several lines of evidence it has been proposed that agrin-like molecules mediate the nerve-induced formation of ... More
Expression of several adhesive macromolecules (N-CAM, L1, J1, NILE, uvomorulin, laminin, fibronectin, and a heparan sulfate proteoglycan) in embryonic, adult, and denervated adult skeletal muscle.
AuthorsSanes JR, Schachner M, Covault J
JournalJ Cell Biol
PubMed ID3511069
'Levels of the neural cell adhesion molecule N-CAM in muscle are regulated in parallel with the susceptibility of muscle to innervation: N-CAM is abundant on the surface of early embryonic myotubes, declines in level as development proceeds, reappears when adult muscles are denervated or paralyzed, and is lost after reinnervation ... More
Rotational diffusion of acetylcholine receptors on cultured rat myotubes.
AuthorsVelez M, Barald KF, Axelrod D
JournalJ Cell Biol
PubMed ID2351693
'The rotational mobility of acetylcholine receptors (AChR) in the plasma membrane of living rat myotubes in culture is measured in this study by polarized fluorescence recovery after photobleaching (PFRAP). These AChR are known to exist in two distinct classes, evident by labeling with rhodamine alpha-bungarotoxin; clustered AChR that are aggregated ... More
Laminin-induced acetylcholine receptor clustering: an alternative pathway.
AuthorsSugiyama JE, Glass DJ, Yancopoulos GD, Hall ZW
JournalJ Cell Biol
PubMed ID9314538
'The induction of acetylcholine receptor (AChR) clustering by neurally released agrin is a critical, early step in the formation of the neuromuscular junction. Laminin, a component of the muscle fiber basal lamina, also induces AChR clustering. We find that induction of AChR clustering in C2 myotubes is specific for laminin-1; ... More
Neuromuscular junctions and alpha-bungarotoxin-binding sites in denervated and contralateral cat skeletal muscles.
AuthorsSteinbach JH
JournalJ Physiol
PubMed ID7277234
'1. The distributions of cholinesterase (ChE) activity and acetylcholine (ACh) receptors were studied in normal and denervated cat hind-limb fast-twitch skeletal muscles and in muscles contralateral to denervated muscles. 2. On normal muscle fibres almost all receptors were confined to the immediately post-junctional membrane, although a perijunctional gradient of increased ... More
Acetylcholine receptor-aggregating proteins are associated with the extracellular matrix of many tissues in Torpedo.
AuthorsGodfrey EW, Dietz ME, Morstad AL, Wallskog PA, Yorde DE
JournalJ Cell Biol
PubMed ID2834403
'The synaptic basal lamina, a component of extracellular matrix (ECM) in the synaptic cleft at the neuromuscular junction, directs the formation of new postsynaptic specializations, including the aggregation of acetylcholine receptors (AChRs), during muscle regeneration in adult animals. Although the molecular basis of this phenomenon is unknown, it is mimicked ... More
Schwann cell apoptosis at developing neuromuscular junctions is regulated by glial growth factor.
AuthorsTrachtenberg JT, Thompson WJ
JournalNature
PubMed ID8538769
'Denervated adult mammalian muscle fibres are reinnervated by regenerating axons and, in the case of partially denervated muscles, by sprouts extended from remaining, intact axons. Recent experiments suggest that Schwann cells (SCs) regulate these events, inducing and guiding axonal outgrowth through the processes they extend. In contrast to adults, reinnervation ... More
The receptor tyrosine kinase MuSK is required for neuromuscular junction formation in vivo.
AuthorsDeChiara TM, Bowen DC, Valenzuela DM, Simmons MV, Poueymirou WT, Thomas S, Kinetz E, Compton DL, Rojas E, Park JS, Smith C, DiStefano PS, Glass DJ, Burden SJ, Yancopoulos GD
JournalCell
PubMed ID8653786
'Formation of neuromuscular synapses requires a series of inductive interactions between growing motor axons and differentiating muscle cells, culminating in the precise juxtaposition of a highly specialized nerve terminal with a complex molecular structure on the postsynaptic muscle surface. The receptors and signaling pathways mediating these inductive interactions are not ... More
A monoclonal antibody that blocks the activity of a neurite regeneration-promoting factor: studies on the binding site and its localization in vivo.
AuthorsChiu AY, Matthew WD, Patterson PH
JournalJ Cell Biol
PubMed ID2945826
'Work from several laboratories has identified a proteoglycan complex secreted by a variety of non-neuronal cells that can promote neurite regeneration when applied to the surface of culture dishes. Using a novel immunization protocol, a monoclonal antibody (INO) was produced that blocks the activity of this outgrowth-promoting factor (Matthew, W. ... More
Regenerating muscle fibers induce directional sprouting from nearby nerve terminals: studies in living mice.
Authorsvan Mier P, Lichtman JW
JournalJ Neurosci
PubMed ID8083762
'The principal aim of this work was to better understand how regenerating muscle fibers become innervated in adult animals. To induce muscle regeneration, individual identified muscle fibers in a mouse were damaged with a laser focused through a microscope. The muscle fiber that degenerated and the muscle fiber that was ... More
Agrin-induced phosphorylation of the acetylcholine receptor regulates cytoskeletal anchoring and clustering.
AuthorsBorges LS, Ferns M
JournalJ Cell Biol
PubMed ID11285269
'At the developing neuromuscular junction, a motoneuron-derived factor called agrin signals through the muscle-specific kinase receptor to induce postsynaptic aggregation of the acetylcholine receptor (AChR). The agrin signaling pathway involves tyrosine phosphorylation of the AChR beta subunit, and we have tested its role in receptor localization by expressing tagged, tyrosine-minus ... More
Hyperinnervation of neuromuscular junctions caused by GDNF overexpression in muscle.
'Overexpression of glial cell line-derived neurotrophic factor (GDNF) by muscle greatly increased the number of motor axons innervating neuromuscular junctions in neonatal mice. The extent of hyperinnervation correlated with the amount of GDNF expressed in four transgenic lines. Overexpression of GDNF by glia and overexpression of neurotrophin-3 and neurotrophin-4 in ... More
Identification of phosphorylation sites on AChR delta-subunit associated with dispersal of AChR clusters on the surface of muscle cells.
AuthorsNimnual AS, Chang W, Chang NS, Ross AF, Gelman MS, Prives JM
JournalBiochemistry
PubMed ID9778356
'The innervation of embryonic skeletal muscle cells is marked by the redistribution of nicotinic acetylcholine receptors (AChRs) on muscle surface membranes into high-density patches at nerve-muscle contacts. To investigate the role of protein phosphorylation pathways in the regulation of AChR surface distribution, we have identified the sites on AChR delta-subunits ... More
Synaptic differentiation can be evoked by polymer microbeads that mimic localized pericellular proteolysis by removing proteins from adjacent surfaces.
AuthorsAnderson MJ, Champaneria S, Swenarchuk LE
JournalDev Biol
PubMed ID1916019
'Synaptic differentiation is normally "induced" by regulatory signals that are exchanged only at close contacts between neurites and their predetermined target cells. These signals can, however, be mimicked by contact of either cell with some kinds of polymer microbeads. To find what bead action is responsible for this mimicry, we ... More
Clustering of muscle acetylcholine receptors requires motoneurons in live embryos, but not in cell culture.
AuthorsLiu DW, Westerfield M
JournalJ Neurosci
PubMed ID1315852
'Previous culture studies have demonstrated that muscle cells autonomously express and cluster ACh receptors (AChRs) and that contact by neurites induces a reorganization of these clusters. We studied these phenomena in zebrafish embryos where the same cells could be examined in vivo and in vitro, and where contacts between cells ... More
Treatment of motoneuron degeneration by intracerebroventricular delivery of VEGF in a rat model of ALS.
AuthorsStorkebaum E, Lambrechts D, Dewerchin M, Moreno-Murciano MP, Appelmans S, Oh H, Van Damme P, Rutten B, Man WY, De Mol M, Wyns S, Manka D, Vermeulen K, Van Den Bosch L, Mertens N, Schmitz C, Robberecht W, Conway EM, Collen D, Moons L, Carmeliet P
JournalNat Neurosci
PubMed ID15568021
'Neurotrophin treatment has so far failed to prolong the survival of individuals affected with amyotrophic lateral sclerosis (ALS), an incurable motoneuron degenerative disorder. Here we show that intracerebroventricular (i.c.v.) delivery of recombinant vascular endothelial growth factor (Vegf) in a SOD1(G93A) rat model of ALS delays onset of paralysis by 17 ... More
Induction of phosphorylation and cell surface redistribution of acetylcholine receptors by phorbol ester and carbamylcholine in cultured chick muscle cells.
AuthorsRoss A, Rapuano M, Prives J
JournalJ Cell Biol
PubMed ID3417778
'We have investigated the mechanisms regulating the clustering of nicotinic acetylcholine receptor (AChR) on the surface of cultured embryonic chick muscle cells. Treatment of these cells with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent activator of protein kinase C, was found to cause a rapid dispersal of AChR clusters, as ... More
Reduction of intramuscular nerve branching and synaptogenesis is correlated with decreased motoneuron survival.
AuthorsTang J, Landmesser L
JournalJ Neurosci
PubMed ID8331387
'Blockade of neuromuscular activity during the period of naturally occurring cell death increases intramuscular nerve branching, synaptogenesis, and survival of embryonic chicken motoneurons. These results suggested that the enhanced motoneuron survival observed might result not from increased production of a trophic factor by the target, as often suggested, but rather ... More
Heterogeneous distribution of a basement membrane heparan sulfate proteoglycan in rat tissues.
AuthorsCouchman JR
JournalJ Cell Biol
PubMed ID2959669
'A heparan sulfate proteoglycan (HSPG) synthesized by murine parietal yolk sac (PYS-2) cells has been characterized and purified from culture supernatants. A monospecific polyclonal antiserum was raised against it which showed activity against the HSPG core protein and basement membrane specificity in immunohistochemical studies on frozen tissue sections from many ... More
In vivo imaging of preferential motor axon outgrowth to and synaptogenesis at prepatterned acetylcholine receptor clusters in embryonic zebrafish skeletal muscle.
AuthorsPanzer JA, Song Y, Balice-Gordon RJ
JournalJ Neurosci
PubMed ID16421313
'Little is known about the spatial and temporal dynamics of presynaptic and postsynaptic specializations that culminate in synaptogenesis. Here, we imaged presynaptic vesicle clusters in motor axons and postsynaptic acetylcholine receptor (AChR) clusters in embryonic zebrafish to study the earliest events in synaptogenesis in vivo. Prepatterned AChR clusters are present ... More
Cell-substrate contacts illuminated by total internal reflection fluorescence.
AuthorsAxelrod D
JournalJ Cell Biol
PubMed ID7014571
'A technique for exciting fluorescence exclusively from regions of contact between cultured cells and the substrate is presented. The technique utilizes the evanescent wave of a totally internally reflecting laser beam to excite only those fluorescent molecules within one light wavelength or less of the substrate surface. Demonstrations of this ... More
The cholinergic antagonist alpha-bungarotoxin also binds and blocks a subset of GABA receptors.
AuthorsMcCann CM, Bracamontes J, Steinbach JH, Sanes JR
JournalProc Natl Acad Sci U S A
PubMed ID16549768
'The polypeptide snake toxin alpha-bungarotoxin (BTX) has been used in hundreds of studies on the structure, function, and development of the neuromuscular junction because it binds tightly and specifically to the nicotinic acetylcholine receptors (nAChRs) at this synapse. We show here that BTX also binds to and blocks a subset ... More
Synaptic segregation at the developing neuromuscular junction.
AuthorsGan WB, Lichtman JW
JournalScience
PubMed ID9822385
'Throughout the developing nervous system, competition between axons causes the permanent removal of some synaptic connections. In mouse neuromuscular junctions at birth, terminal branches of different axons are intermingled. However, during the several weeks after birth, these branches progressively segregated into nonoverlapping compartments before the complete withdrawal of all but ... More
Insertion and internalization of acetylcholine receptors at clustered and diffuse domains on cultured myotubes.
AuthorsBursztajn S, Berman SA, McManaman JL, Watson ML
JournalJ Cell Biol
PubMed ID4008524
'Two populations of acetylcholine receptors (AChRs) are present in cultured myotubes. One forms large aggregates or clusters and the other has a much lower density of AChRs, which are diffusely distributed. Both clustered and diffuse AChRs are inserted and removed (internalized) from the sarcolemma. To determine the insertion and removal ... More
Crosslinkage and visualization of acetylcholine receptors on myotubes with biotinylated alpha-bungarotoxin and fluorescent avidin.
AuthorsAxelrod D
JournalProc Natl Acad Sci U S A
PubMed ID6933533
'A biotinylated derivative of alpha-bungarotoxin and tetramethylrhodamine-labeled avidin were employed to fluorescence label the acetylcholine receptors (AcChoR) on the surface of rat myotubes in primary culture. Because of the multivalency of both the biotinylated bungarotoxin and the avidin, this treatment extensivey crosslinks the AcChoR. AcChoR crosslinking immobilizes more than 90% ... More
A factor from neurons induces partial immobilization of nonclustered acetylcholine receptors on cultured muscle cells.
AuthorsAxelrod D, Bauer HC, Stya M, Christian CN
JournalJ Cell Biol
PubMed ID7204502
'A factor or factors released by cultured NG108-15 neuroblastoma X glioma hybrid cells and added to the medium of rat myotube primary cultures was found to immobilize some of the previously mobile acetylcholine receptors in the myotube membrane. Partial receptor immobilization occurred within 3 h after the beginning of treatment ... More
The submembrane machinery for nicotinic acetylcholine receptor clustering.
AuthorsFroehner SC
JournalJ Cell Biol
PubMed ID2050736
Correlation between acetylcholine receptor localization and spontaneous synaptic potentials in cultures of nerve and muscle.
AuthorsAnderson MJ, Kidokoro Y, Gruener R
JournalBrain Res
PubMed ID217499
Fluorescent tetramethyl rhodamine derivatives of alpha-bungarotoxin: preparation, separation, and characterization.
AuthorsRavdin P, Axelrod D
JournalAnal Biochem
PubMed ID889094
Simultaneous visualization of acetylcholinesterase activity and acetylcholine receptor clusters at neuromuscular synapses in vivo and in vitro.
AuthorsDo Thi A, De La Porte S, Koenig J
JournalBiol Cell
PubMed ID6234043
Our double labelling method allows the junctional AChE and AChR distributions to be stained in the same preparation. This method which provides good definition of the fine morphology of synaptic structure and is capable of revealing a very weak AChE activity is of a particular value in studies of synaptogenesis. ... More
a2-Chimaerin regulates a key axon guidance transition during development of the oculomotor projection.
AuthorsClark C, Austen O, Poparic I, Guthrie S,
Journal
PubMed ID24133258
The ocular motor system consists of three nerves which innervate six muscles to control eye movements. In humans, defective development of this system leads to eye movement disorders, such as Duane Retraction Syndrome, which can result from mutations in the a2-chimaerin signaling molecule. We have used the zebrafish to model ... More
Increased expression of the 43-kD protein disrupts acetylcholine receptor clustering in myotubes.
AuthorsYoshihara CM, Hall ZW
JournalJ Cell Biol
PubMed ID7686162
The 43-kD protein is a peripheral membrane protein that is in approximately 1:1 stoichiometry with the acetylcholine receptor (AChR) in vertebrate muscle cells and colocalizes with it in the postsynaptic membrane. To investigate the role of the 43-kD protein in AChR clustering, we have isolated C2 muscle cell lines in ... More
One of the important events in synapse formation is the accumulation of neurotransmitter receptors beneath the presynaptic nerve terminal. Agrin is a component of the synaptic basal lamina that induces the clustering of acetylcholine receptors when bath-applied to muscle fibers in culture. When a cDNA encoding a putative agrin protein ... More
Organization of acetylcholine receptor clusters in cultured rat myotubes is calcium dependent.
AuthorsBursztajn S, McManaman JL, Appel SH
JournalJ Cell Biol
PubMed ID6693492
The effect of extracellular Ca2+ concentration and myasthenic globulin on the distribution and appearance of acetylcholine receptor (AChR) clusters on rat myotubes was studied with tetramethyl-rhodamine-labeled alpha BTX. Low Ca2+ medium (2.5 X 10(-5) M) caused a time-dependent loss of AChR clusters, and a concomitant increase in small punctate areas ... More
Pathfinding and synapse formation in a zebrafish mutant lacking functional acetylcholine receptors.
AuthorsWesterfield M, Liu DW, Kimmel CB, Walker C
JournalNeuron
PubMed ID2361010
We induced and characterized a recessive lethal mutation, nic-1, in zebrafish that blocks the function of muscle acetylcholine (ACh) receptors. Homozygous nic-1 embryos are nonmotile and fail to respond to exogenous application of cholinergic agonists, although their muscles contract in response to direct electrical stimulation. Moreover, we do not detect ... More
A synaptic localization domain in the synaptic cleft protein laminin beta 2 (s-laminin)
AuthorsMartin PT, Ettinger AJ, Sanes JR
JournalScience
PubMed ID7618109
The basal lamina that ensheaths skeletal muscle fibers traverses the synaptic cleft at the neuromuscular junction. Synaptic and extrasynaptic portions of the basal lamina contain different laminin beta chains: beta 2 (or s) at synapses and beta 1 (or B1) extrasynaptically. Laminin beta 2 is also confined to synapselike patches ... More
Microinjection of a monoclonal antibody against a 37-kD protein (tropomyosin 2) prevents the formation of new acetylcholine receptor clusters.
AuthorsMarazzi G, Bard F, Klymkowsky MW, Rubin LL
JournalJ Cell Biol
PubMed ID2808531
We have shown previously that chick muscle cells transformed with Rous sarcoma virus are unable to form clusters of acetylcholine receptors (AChRs) (Anthony, D. T., S. M. Schuetze, and L. L. Rubin. 1984. Proc. Natl. Acad. Sci. USA. 81:2265-2269) and are missing a 37-KD tropomyosin-like protein (TM-2) (Anthony, D. T., ... More
Aggregation of sodium channels during development and maturation of the neuromuscular junction.
The voltage-activated Na channel (NaCh) is an integral membrane protein that is enriched at the neuromuscular end plate. Using loose-patch voltage-clamp and immunofluorescence, we have found that the aggregation of NaChs occurs late, during maturation of the neuromuscular junction. A decline in expression of embryonic NaCh mRNA and increase in ... More
Fluorophore-assisted light inactivation produces both targeted and collateral effects on N-type calcium channel modulation in rat sympathetic neurons.
AuthorsGuo J, Chen H, Puhl HL, Ikeda SR,
JournalJ Physiol
PubMed ID16873413
Fluorophore-assisted light inactivation (FALI) is a method to inactivate specific proteins on a time scale of seconds to minutes using either diffuse or coherent light. Here we examine a novel FALI modality that utilizes a fluorescein-conjugated polypeptide, alpha-bungarotoxin (BTX) and a 13 amino acid BTX-binding site engineered into the N-terminus ... More
Visualization of integral and peripheral cell surface proteins in live Caenorhabditis elegans.
AuthorsGottschalk A, Schafer WR,
JournalJ Neurosci Methods
PubMed ID16466809
To study the abundance of specific receptors and other cell surface proteins at synapses, it would be advantageous to specifically label these proteins only when inserted in the plasma membrane. We describe a method that allows to fluorescently label cell surface proteins in live and behaving animals, namely in the ... More
Neurotransmitter receptor dynamics studied in vivo by reversible photo-unbinding of fluorescent ligands.
AuthorsAkaaboune M, Grady RM, Turney S, Sanes JR, Lichtman JW
JournalNeuron
PubMed ID12086635
We show that fluorescently tagged ligands with high affinity for their targets can be reversibly unbound by focused laser excitation. By sequential unbinding and relabeling with different colors of alpha-bungarotoxin, we selectively labeled adjacent pools of acetylcholine receptors (AChRs) at neuromuscular junctions of adult mice. Timelapse imaging in vivo revealed ... More
Dystrophin is a component of the subsynaptic membrane.
AuthorsYeadon JE, Lin H, Dyer SM, Burden SJ
JournalJ Cell Biol
PubMed ID1720119
A subsynaptic protein of Mr approximately 300 kD is a major component of Torpedo electric organ postsynaptic membranes and copurifies with the AChR and the 43-kD subsynaptic protein. mAbs against this protein react with neuromuscular synapses in higher vertebrates, but not at synapses in dystrophic muscle. The Torpedo 300-kD protein ... More
Isolation of acetylcholine receptor clusters in substrate-associated material from cultured rat myotubes using saponin.
AuthorsBloch RJ
JournalJ Cell Biol
PubMed ID6381511
After exposure of rat myotube cultures to saponin, less than 1% of the cellular protein was found to remain associated with the tissue culture substrate. This substrate-associated material contained approximately 10% of the acetylcholine receptors (AChRs) and greater than 80% of the large, ventral AChR clusters present in the original ... More
Asynchronous synapse elimination in neonatal motor units: studies using GFP transgenic mice.
In developing muscle, synapse elimination reduces the number of motor axons that innervate each postsynaptic cell. This loss of connections is thought to be a consequence of axon branch trimming. However, branch retraction has not been observed directly, and many questions remain, such as: do all motor axons retract branches, ... More
Rapid and reversible effects of activity on acetylcholine receptor density at the neuromuscular junction in vivo.
AuthorsAkaaboune M, Culican SM, Turney SG, Lichtman JW
JournalScience
PubMed ID10521340
Quantitative fluorescence imaging was used to study the regulation of acetylcholine receptor (AChR) number and density at neuromuscular junctions in living adult mice. At fully functional synapses, AChRs have a half-life of about 14 days. However, 2 hours after neurotransmission was blocked, the half-life of the AChRs was now less ... More
Identification and molecular characterization of Unc-33-like phosphoprotein (Ulip), a putative mammalian homolog of the axonal guidance-associated unc-33 gene product.
AuthorsByk T, Dobransky T, Cifuentes-Diaz C, Sobel A
JournalJ Neurosci
PubMed ID8551352
The control of neuritic extension and guidance is critical for the development, maturation, and regeneration of functional neuronal circuits. We identified a neuronal 64-85 kDa phosphoprotein, the expression of which in mouse brain is regulated during development, reaching a peak at approximately 5 d postnatal, when maturation of neurons and ... More
Alterations in synaptic strength preceding axon withdrawal.
AuthorsColman H, Nabekura J, Lichtman JW
JournalScience
PubMed ID8994026
Permanent removal of axonal input to postsynaptic cells helps shape the pattern of neuronal connections in response to experience, but the process is poorly understood. Intracellular recording from newborn and adult mouse muscle fibers temporarily innervated by two axons showed an increasing disparity in the synaptic strengths of the two ... More
Lateral motion of fluorescently labeled acetylcholine receptors in membranes of developing muscle fibers.
AuthorsAxelrod D, Ravdin P, Koppel DE, Schlessinger J, Webb WW, Elson EL, Podleski TR
JournalProc Natl Acad Sci U S A
PubMed ID1070010
We have made direct, quantitative measurements of the lateral motion and age-dependent distribution of acetylcholine receptors (AChR) on the surface of rat myotubes in primary culture. AChR were fluorescently marked with tetramethylrhodamine-labeled alpha-bungarotoxin and AChR lateral motion was measured by the fluoresence photobleaching recovery technique. We found two coexisting distinct ... More
The putative agrin receptor binds ligand in a calcium-dependent manner and aggregates during agrin-induced acetylcholine receptor clustering.
AuthorsNastuk MA, Lieth E, Ma JY, Cardasis CA, Moynihan EB, McKechnie BA, Fallon JR
JournalNeuron
PubMed ID1660286
Agrin derived from Torpedo electric organ induces the clustering of acetylcholine receptors (AChRs) on cultured myotubes. As a first step toward characterizing the plasma membrane receptor for agrin, we have examined agrin binding to cultured myotubes. Agrin binding is saturable as measured by radioimmunoassay and, like agrin-induced AChR clustering, requires ... More
Association of dystrophin-related protein with dystrophin-associated proteins in mdx mouse muscle.
Dystrophin is associated with a complex of muscle membrane (sarcolemmal) glycoproteins that provide a linkage to the extracellular matrix protein, laminin. The absence of dystrophin leads to a dramatic reduction of the dystrophin-associated proteins (156DAG, 59DAP, 50DAG, 43DAG and 35DAG) in the sarcolemma of patients with Duchenne muscular dystrophy and ... More
Enhanced molecular diffusibility in muscle membrane blebs: release of lateral constraints.
AuthorsTank DW, Wu ES, Webb WW
JournalJ Cell Biol
PubMed ID7199052
Measurements of lateral molecular diffusion on blebs formed on the surfaces of isolated muscle cells and myoblasts are reported. These blebbed membranes retain integral proteins but apparently separate from the detectable cytoskeleton. On blebs, acetylcholine receptors, concanavalin A receptors, and stearoyldextran extrinsic model receptor molecules are free to diffuse with ... More
LL5beta: a regulator of postsynaptic differentiation identified in a screen for synaptically enriched transcripts at the neuromuscular junction.
AuthorsKishi M, Kummer TT, Eglen SJ, Sanes JR
JournalJ Cell Biol
PubMed ID15851520
In both neurons and muscle fibers, specific mRNAs are concentrated beneath and locally translated at synaptic sites. At the skeletal neuromuscular junction, all synaptic RNAs identified to date encode synaptic components. Using microarrays, we compared RNAs in synapse-rich and -free regions of muscles, thereby identifying transcripts that are enriched near ... More
Acetylcholine receptor clustering and nuclear movement in muscle fibers in culture.
AuthorsEnglander LL, Rubin LL
JournalJ Cell Biol
PubMed ID3793762
We have studied the formation of acetylcholine receptor (AChR) clusters and the behavior of myonuclei in rat and chick skeletal muscle cells grown in cell culture. These cells were treated with a factor derived from Torpedo electric extracellular matrix, which causes a large increase in their number of AChR clusters. ... More
Spatial variability in release at the frog neuromuscular junction measured with FM1-43.
AuthorsWu LG, Betz WJ
JournalCan J Physiol Pharmacol
PubMed ID10566944
We quantified the spatial variability in release properties at different synaptic vesicle clusters in frog motor nerve terminals, using a combination of fluorescence and electron microscopy. Individual synaptic vesicle clusters labeled with FM1-43 varied more than 10-fold in initial intensity (integrated FM1-43 fluorescence) and in absolute rate of dye loss ... More
Deletion of murine SMN exon 7 directed to skeletal muscle leads to severe muscular dystrophy.
AuthorsCifuentes-Diaz C, Frugier T, Tiziano FD, Lacène E, Roblot N, Joshi V, Moreau MH, Melki J
JournalJ Cell Biol
PubMed ID11238465
Spinal muscular atrophy (SMA) is characterized by degeneration of motor neurons of the spinal cord associated with muscle paralysis and caused by mutations of the survival motor neuron gene (SMN). To determine whether SMN gene defect in skeletal muscle might have a role in SMA pathogenesis, deletion of murine SMN ... More
Muscle activity and muscle agrin regulate the organization of cytoskeletal proteins and attached acetylcholine receptor (AchR) aggregates in skeletal muscle fibers.
AuthorsBezakova G, Lømo T
JournalJ Cell Biol
PubMed ID11425875
In innervated skeletal muscle fibers, dystrophin and beta-dystroglycan form rib-like structures (costameres) that appear as predominantly transverse stripes over Z and M lines. Here, we show that the orientation of these stripes becomes longitudinal in denervated muscles and transverse again in denervated electrically stimulated muscles. Skeletal muscle fibers express nonneural ... More
Acetylcholine and calcium signalling regulates muscle fibre formation in the zebrafish embryo.
AuthorsBrennan C, Mangoli M, Dyer CE, Ashworth R
JournalJ Cell Sci
PubMed ID16249237
Nerve activity is known to be an important regulator of muscle phenotype in the adult, but its contribution to muscle development during embryogenesis remains unresolved. We used the zebrafish embryo and in vivo imaging approaches to address the role of activity-generated signals, acetylcholine and intracellular calcium, in vertebrate slow muscle ... More
Increases in pericellular proteolysis at developing neuromuscular junctions in culture.
AuthorsChampaneria S, Swenarchuk LE, Anderson MJ
JournalDev Biol
PubMed ID1730384
To determine whether localized changes in pericellular proteolysis contribute to synapse formation, we examined the degradative actions of developing Xenopus laevis nerve and muscle cells on films of extracellular matrix proteins adsorbed to the glass surface of a tissue culture chamber. Skeletal myocytes, growing neurites, and fibroblasts all removed fluorescent ... More
Localization of acetylcholine receptors and cholinesterase on nerve-contacted and noncontacted muscle cells grown in the presence of agents that block action potentials.
AuthorsDavey DF, Cohen MW
JournalJ Neurosci
PubMed ID3958789
The possible role of nerve activity in triggering changes in the localization of acetylcholine receptors (AChRs) and cholinesterase (ChE) on nerve-contacted Xenopus muscle cells has been assessed. The localization of these molecules was examined on nerve-contacted and noncontacted muscle cells in cultures of spinal cord and myotomal muscle derived from ... More
Early cytoplasmic specialization at the presumptive acetylcholine receptor cluster: a meshwork of thin filaments.
AuthorsPeng HB, Phelan KA
JournalJ Cell Biol
PubMed ID6539783
Postsynaptic differentiation can be experimentally induced in cultured Xenopus myotomal muscle cells by polyornithine-coated latex beads (Peng, H. B., and P.-C. Cheng, 1982, J. Neurosci., 2:1760-1774). In this study, we examined the time course of this process. Small, punctate acetylcholine receptor (AChR) clusters were detectable as early as 1.5 h ... More
Syne-1, a dystrophin- and Klarsicht-related protein associated with synaptic nuclei at the neuromuscular junction.
AuthorsApel ED, Lewis RM, Grady RM, Sanes JR
JournalJ Biol Chem
PubMed ID10878022
We describe a novel protein, Syne-1, that is associated with nuclear envelopes in skeletal, cardiac, and smooth muscle cells. Syne-1 contains multiple spectrin repeats similar to those found in dystrophin and utrophin, as well as a domain homologous to the carboxyl-terminal of Klarsicht, a protein associated with nuclei and required ... More
Erbin is a protein concentrated at postsynaptic membranes that interacts with PSD-95.
AuthorsHuang YZ, Wang Q, Xiong WC, Mei L
JournalJ Biol Chem
PubMed ID11279080
Neuregulin is a factor essential for synapse-specific transcription of acetylcholine receptor genes at the neuromuscular junction. Its receptors, ErbB receptor tyrosine kinases, are localized at the postjunctional membrane presumably to ensure localized signaling. However, the molecular mechanisms underlying synaptic localization of ErbBs are unknown. Our recent studies indicate that ErbB4 ... More