A5001675109- Ion channel regulation and function
- Neuroscience and Neuropharmacology Research
- Muscle Physiology and Disorders
- Neuroscience and Neural Engineering
- Adipose Tissue and Metabolism
- Alzheimer's disease research and treatments
- Protease and Inhibitor Mechanisms
- Nicotinic Acetylcholine Receptors Study
- Cellular transport and secretion
- Exercise and Physiological Responses
- Lipid Membrane Structure and Behavior
- Cholinesterase and Neurodegenerative Diseases
- S100 Proteins and Annexins
- Parkinson's Disease Mechanisms and Treatments
- Neurobiology and Insect Physiology Research
- Economic Theory and Policy
- Amyotrophic Lateral Sclerosis Research
- Prion Diseases and Protein Misfolding
- Medicinal Plants and Neuroprotection
- Blood Coagulation and Thrombosis Mechanisms
- Receptor Mechanisms and Signaling
- RNA regulation and disease
- Biotin and Related Studies
- Genetic Neurodegenerative Diseases
- Neurogenetic and Muscular Disorders Research
University of Michigan
2013-2025
Hamad bin Khalifa University
2017
Institut thématique Génétique, génomique et bioinformatique
2005-2015
Michigan United
2013
Washington University in St. Louis
1999-2003
Inserm
1993-2000
Institut de Myologie
1998-2000
Sidi Mohamed Ben Abdellah University
1998-2000
Centre National de la Recherche Scientifique
1993-1995
Institut du Fer à Moulin
1995
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 about 14 days. However, 2 hours after neurotransmission blocked, now less than day; rate 25 times faster before. Most lost receptors were not quickly replaced. Direct muscle stimulation or restoration synaptic transmission inhibited this process. that removed from...
Neuregulin (NRG)/ErbB signaling is involved in numerous developmental processes the nervous system, including synapse formation and function central system. Although intensively investigated, its role at neuromuscular has remained elusive. Here, we demonstrate that loss of NRG/ErbB destabilized anchoring acetylcholine receptors (AChRs) postsynaptic muscle membrane this effect was caused by dephosphorylation α-dystrobrevin1, a component scaffold. Specifically, mice which NRG to genetically or...
In the CNS, receptor recycling is critical for synaptic plasticity; however, of receptors has never been observed at peripheral synapses. Using a novel imaging technique, we show here that nicotinic acetylcholine (AChRs) recycle into postsynaptic membrane neuromuscular junction. By sequentially labeling AChRs with biotin-bungarotoxin and streptavidin-fluorophore conjugates, were able to distinguish recycled, preexisting, new pools synapses in living mice. Time-lapse revealed recycled...
α-Dystrobrevin (DB), a cytoplasmic component of the dystrophin–glycoprotein complex, is found throughout sarcolemma muscle cells. Mice lacking αDB exhibit muscular dystrophy, defects in maturation neuromuscular junctions (NMJs) and, as shown here, abnormal myotendinous (MTJs). In normal muscle, alternative splicing produces two main isoforms, αDB1 and αDB2, with common NH2-terminal but distinct COOH-terminal domains. αDB1, whose extension can be tyrosine phosphorylated, concentrated at NMJs...
At the peripheral neuromuscular junction (NMJ), a significant number of nicotinic acetylcholine receptors (AChRs) recycle back into postsynaptic membrane after internalization to intermingle with not-yet-internalized`pre-existing' AChRs. However, way in which these receptor pools are maintained and regulated at NMJ living animals remains unknown. Here,we demonstrate that recycled functional synapses removed approximately four times faster than pre-existing receptors, most replaced by new...
At the mammalian skeletal neuromuscular junction, cycling of nicotinic ACh receptors (nAChRs) is critical for maintenance a high postsynaptic receptor density. However, mechanisms that regulate nAChRs recycling in living animals remain unknown. Using vivo time-lapse imaging, fluorescence recovery after photobleaching, and biochemical pull down assays, we demonstrated internalized into fully functional denervated synapses was promoted by both direct muscle stimulation pharmacologically...
A hallmark of the neuromuscular junction (NMJ) is high density acetylcholine receptors (AChRs) in postsynaptic muscle membrane. The apparatus NMJ organized by agrin secreted from motor neurons. mechanisms that underlie focal delivery AChRs to adult are not yet understood detail. We previously showed microtubule (MT) capture plus end-tracking protein CLASP2 regulates AChR at agrin-induced clusters cultured myotubes via PI3 kinase acting through GSK3β. Here we show knockdown CLASP2-interaction...
Intronic GGGGCC repeat expansions in C9orf72 are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Two major pathologies stemming from hexanucleotide RNA (HREs) have been identified postmortem tissue: intracellular foci repeat-associated non-ATG dependent (RAN) dipeptides, though it is unclear how these other hallmarks disease contribute to pathophysiology neuronal injury. Here we generated two novel lines mice that overexpress either 10...
Abstract: We addressed the balance between thrombin and its serpin protease nexin I (PNI) after sciatic nerve injury in mouse. Prothrombin levels increased twofold 24 h crush, as measured by a specific chromogenic assay, peaked at day 3. Thrombin activity also 2–4 days distal segments. Nerve RNA analysis using reverse transcriptase‐polymerase chain reaction (RT‐PCR) assay confirmed that prothrombin was synthesized locally. monitored PNI these injured samples complex formation with an 125...
At cholinergic synapses, acetylcholinesterase (AChE) is critical for ensuring normal synaptic transmission. However, little known about how this enzyme maintained and regulated in vivo. In work, we demonstrate that the dissociation of fluorescently-tagged fasciculin 2 (a specific selective peptide inhibitor AChE) from AChE extremely slow. This fluorescent probe was used to study removal insertion at individual synapses living adult mice. After a one-time blockade AChEs with 2, are removed...
The steady state of the acetylcholine receptor (AChR) density at neuromuscular junction (NMJ) is critical for efficient and reliable synaptic transmission. However, little known about signaling molecules involved in regulating equilibrium between removal insertion AChRs that establishes a stable postsynaptic over time. In this work, we tested effect activities two serine/threonine kinases, PKC PKA, on rate from re-insertion internalized recycled into sites innervated denervated NMJs living...
The efficacy of synaptic transmission depends on the maintenance a high density neurotransmitter receptors and their associated scaffold proteins in postsynaptic membrane. While dynamics has been extensively studied, intracellular that make up are largely unknown vivo . Here, we focused rapsyn, protein required for clustering acetylcholine receptor (AChR) at sites. Using time-lapse imaging, demonstrated rapsyn is remarkably dynamic compared to AChRs functional synapses, turning over 4–6...
α-Syntrophin (α-syn), a scaffold protein, links signaling molecules to the dystrophin–glycoprotein complex. Absence of α-syn from DGC is known lead structurally aberrant neuromuscular junctions (NMJs) with few acetylcholine receptors (AChRs) clustered at synaptic sites. Using knock-out mice, we show that during first postnatal week, not required for synapse formation. However, day 6 (P6)–P7, structural integrity postsynaptic apparatus altered, turnover rate AChRs increases significantly, and...
Rapsyn, a 43 kDa scaffold protein, is required for the clustering of acetylcholine receptors (AChRs) at synaptic sites between mammalian motor neurons and muscle cells. However, mechanism by which rapsyn inserted retained postsynaptic neuromuscular junction (NMJ) in vivo remains largely unknown. We found that neither N-terminal myristoylation nor cysteine-rich RING H2 domain its stable association with membrane NMJs. When N-myristoylation-defective rapsyn-EGFP mutant (G2A) RING-H2 truncated...
We examined the localization of normal cellular isoform prion protein (PrPc) in mammalian skeletal muscle. Using two anti-PrP antibodies, neuromuscular junction (NMJ) was preferentially stained after immunohistofluorescence. The mouse, hamster, and human NMJ displayed a fluorescent signal specific for PrPc. Postembedding immunoelectron microscopy analysis performed mouse muscle showed that PrPc-specific colloidal gold immunolabelling concentrated over sarcoplasmic cytoplasm. membrane...
αkap, a muscle specific anchoring protein encoded within the Camk2a gene, is thought to play role in targeting multiple calcium/calmodulin kinase II isoforms subcellular locations. Here we demonstrate novel function of αkap stabilizing nicotinic acetylcholine receptors (AChRs). Knockdown expression with shRNA significantly enhanced degradation AChR α-subunits (AChRα), leading fewer and smaller clusters on surface differentiated C2C12 myotubes. Mutagenesis biochemical studies HEK293T cells...