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Colocalization of synapsin and actin during synaptic vesicle recycling -- Bloom et al. 161 (4): 737 -- The Journal of ... The activity-dependent migration of synapsin to the endocytic of synapsin from vesicles, its migration is delimited by the Impairment of synaptic vesicle clustering and of synaptic transmission, and increased seizure propensity, in synapsin I-deficient mice. www.jcb.org /cgi/content/full/161/4/737   (5809 words)

Molecular Foundation Each synapsin is a mosaic composed of pretty conserved N-terminal A, B and C domains and a variable C terminus. All synapsins are widely distributed in nerve terminals, but that their relative amounts vary among different kinds of synapses suggesting common and different roles of each in the integration of distinct signal transduction pathways that modulate neurotransmitter release in various types of neurons. Synapsin is located in a distal portion from the active zone in several preparations, including granule cell axon-Purkinje cell dendrite {{163 Hirokawa,N. www.stanford.edu /~xujing/Synapsin.htm   (1355 words)

Cloning from Insulinoma Cells of Synapsin I Associated with Insulin Secretory Granules -- Matsumoto et al. 274 (4): ... Synapsin I is a synaptic vesicle-associated protein involved in neurotransmitter release. synapsin Ia and Ib and synapsin IIa and IIb. We demonstrated the expression of synapsin I in isolated islets from rat pancreas by RT-PCR with RNA from islets (Fig. www.jbc.org /cgi/content/full/274/4/2053   (4878 words)

Schizophrenia and Synapsin The levels of the synaptic vesicle-associated proteins, synapsin and synaptophysin, were examined in human postmortem hippocampus from the brains of schizophrenics and age-matched controls using a quantitative western blot analysis. This deficit in synapsin does not appear to be due to some non-specific neuronal loss as the levels of the other synaptic vesicle marker, synaptophysin, were near normal in all seven schizophrenics. Given that synapsin is thought to regulate neurotransmitter release, it is possible that this deficit in synapsin could result in abnormal processing of neuronal information as is seen in various sensory processing abnormalities associated with schizophrenia. www2.uchsc.edu /pharm/Faculty/Browning/schiz.asp   (162 words)

Excitation and Conduction   (Site not responding. Last check: 2007-10-19) Synapsins could be recognized using immunogold EM techniques, or from their distinctive morphology with a head region 14 nm in diameter and a filamentous portion 33 nm long. The binding of synapsin II to actin produces actin bundles in vitro; this bundling is decreased when the synapsin is phosphorylated by CaM kinase II (Bähler and Greengard, 1987, Petrucci and Morrow, 1987). Therefore, synapsin is probably responsible for the trapping of the vesicles in the cytoskeletal network, and synapsin can release the vesicles when phosphorylated in response to an increase in Ca A physiological cycle of this kind is supported by computer simulations (Benfenati et al., 1991). www.albany.edu /~abio304/text/22part3.html   (9805 words)

Synapsin-regulated synaptic transmission from readily releasable synaptic vesicles in excitatory hippocampal synapses ... slices from mice devoid of synapsins I and II and from wild-type the presence of synapsins I and II minimized the early responses the latter synapse, the presence of synapsins I and II enhanced jp.physoc.org /cgi/content/abstract/571/1/75   (294 words)

Diabetes: Site-Specific Phosphorylation of Synapsin I by [Ca.sup.2+]/Calmodulin-Dependent Protein Kinase II in ...   (Site not responding. Last check: 2007-10-19) Synapsin I was observed to be perinuclear and dispersed throughout the cytoplasm of [Beta]TC3 cells, consistent with its potential association with secretory machinery (Fig. Synapsin I was routinely detected as a doublet band in immunoblot and immunoprecipitation analyses of clonal [Beta]-cells or islets (not clear from figure illustrations) and, as such, was reminiscent of neuronal expression of splice variants synapsin I a/b (41). Importantly, synapsin I was also detected in primary islets Coy immunoblot and immunofluorescence), eliminating the possibility that synapsin I expression in [Beta]TC3 cells was the result of phenotypic changes often characteristic of immortalized [Beta]-cells maintained in long-term culture (42). www.findarticles.com /p/articles/mi_m0922/is_3_48/ai_54145954/pg_3   (1023 words)

RedNova News - Science - Using the Atomic Force Microscope to Study the Interaction Between Two Solid Supported Lipid ...   (Site not responding. Last check: 2007-10-19) Synapsin I binds with high affinity to acidic phospholipids, such as phosphatidyl-serine or phosphatidylinositol, that are enriched in the cytoplasmic leaflet of the synaptic vesicle membrane (Benfenati et al., 1989a,b). Although the binding of synapsin I involves penetration of the hydrophobic central C domain into the hydrophobic core of the membrane (Benfenati et al., 1989a,b; Stefani et al., 1997), it is not accompanied by either permeabilization or destabil ization of the bilayer. Synapsin I was purified to homogeneity from calf brain under nondenaturing conditions as previously \described (Bhler and Greengard, 1987). www.rednova.com /news/display?id=98259   (6486 words)

BioMed Central | Full text | The conserved protein kinase-A target motif in synapsin of Drosophilais effectively ... Synapsins are abundant synaptic vesicle associated phosphoproteins that are involved in the fine regulation of neurotransmitter release. However, synapsins have also been proposed to be involved in various other neuronal activities, including neurite elongation, synaptogenesis, synaptic maturation, and synaptic plasticity [15-21]. Since synapsin knock-out flies are impaired in learning and/or memory [27,28] we speculate that phosphorylation of Drosophila synapsin in the A domain is subject to cell-specific fine regulation by RNA editing. www.biomedcentral.com /1471-2202/7/76   (5357 words)

Frederikse, Mol Vis 2004; 10:794-804. Synapsin, synaptotagmin I, and synaptophysin proteins were more readily detected in crude insoluble fractions, suggesting associations with membrane vesicles and cytoskeleton similar to neurons, and experiments are underway to investigate these possibilities. In contrast, little or no synapsin I was detected in rapidly elongating fibers at this stage, Figure 2H appearing similar to the negative control in Figure 2K, however this antibody does identify Synapsin I protein in adult mouse lens and brain protein samples on immunoblots (Figure 1B). In Figure 4 phosphorylated and de-phosphorylated synapsins are again demonstrated along the axial length of E15.5 mouse lens fiber cells, consistent with the distributions of synapsins in E17 rat lens (Figure 2). www.molvis.org /molvis/v10/a94   (5548 words)

Rat Genome Database: References Synapsins I and II are synaptic vesicle proteins essential for normal Ca2+ regulation of neurotransmitter release. Synapsins are composed of combinations of common and variable sequences, with the central C-domain as the largest conserved domain. ATP binding to the different synapsins is directly regulated by Ca2+ in a dramatically different fashion: Ca2+ activates ATP binding to synapsin I, has no effect on synapsin II, and inhibits synapsin III. rgd.mcw.edu /tools/references/references_view.cgi?id=70029   (255 words)

Synapsin Is a Novel Rab3 Effector Protein on Small Synaptic Vesicles: II. FUNCTIONAL EFFECTS OF THE Rab3A-SYNAPSIN I ... bovine synapsin I was stoichiometrically phosphorylated in vitro SV depleted of endogenous synapsin I or rebound to exogenous decreased by the reassociation of synapsin I with the SV membrane www.jbc.org /cgi/content/full/279/42/43769   (7110 words)

Changes in Retinal Synaptic Proteins in the Transgenic Model Expressing a Mutant HRG4 (UNC119) -- Kubota et al. 43 (2): ... Immunofluorescence micrographs of synapsin (A), synaptotagmin (B), and syntaxin-1B (C) in 13-month-old transgenic retina. The absence of synapsin immunofluorescence in the mouse retina in the transgenic retina (synapsin IIa, synaptotagmin, and Doc2) www.iovs.org /cgi/content/full/43/2/308   (3727 words)

From the Cover: Protein fucosylation regulates synapsin Ia/Ib expression and neuronal morphology in primary hippocampal ... that synapsins Ia and Ib are the predominant Fuc Synapsin I-transfected HeLa cells were treated with the indicated amounts of the deoxy sugar for 24 h. Synapsin I-transfected HeLa cells were treated with the indicated inhibitors or vehicle control (DMSO, PBS, or MeOH) in the presence or absence of 2-dGal for 15 h. www.pnas.org /cgi/content/full/103/1/21   (4079 words)

Dde-I Restriction Endonuclease Fragmentation: A Novel Method of Generating cDNA Probes for In Situ Hybridization in ... Haas CA, DeGennaro LJ (1988) Multiple synapsin I messenger RNAs are differentially regulated during neonatal development. Melloni RH, Jr, Apostolides PJ, Hamos JE, DeGennaro LJ (1994) Dynamics of synapsin I gene expression during the establishment and restoration of functional synapses in the rat hippocampus. Melloni RH, Jr, Hemmendinger LM, Hamos JE, DeGennaro LJ (1993) Synapsin I gene expression in the adult rat brain with comparative analysis of mRNA and protein in the hippocampus. www.jhc.org /cgi/content/full/45/5/755   (4853 words)

Expression of a synapsin IIb site 1 phosphorylation mutant in 3T3-L1 adipocytes inhibits basal intracellular retention ... Salt and Triton extraction of synapsin from microsomes. Synapsin IIb is released into the soluble fraction by salt treatment, but remains associated with the particulate fraction after addition of TX100. (E,F) Similar levels of synapsin were expressed from all viruses, at approximately the same levels as in the brain, and all cells positive for GFP fluorescence (HA-Glut4/GFP) were also positive for Flag labeling in cells expressing WT- or S10A synapsin. jcs.biologists.org /cgi/content/full/120/7/1168/DC1   (639 words)

Synapsins: mosaics of shared and individual domains in a family of synaptic vesicle phosphoproteins -- Sudhof et al. ... Synapsins are neuronal phosphoproteins that coat synaptic vesicles, bind to the cytoskeleton, and are believed to function in the regulation of neurotransmitter release. Each synapsin is a mosaic composed of homologous amino-terminal domains common to all synapsins and different combinations of distinct carboxyl-terminal domains. Synapsins regulate use-dependent synaptic plasticity in the calyx of Held by a Ca2+/calmodulin-dependent pathway. www.sciencemag.org /cgi/content/abstract/245/4925/1474   (1399 words)

Norepinephrine and isoproterenol increase the phosphorylation of synapsin I and synapsin II in dentate slices of young ... Norepinephrine and isoproterenol increase the phosphorylation of synapsin I and synapsin II in dentate slices of young but not aged Fisher 344 rats.A number of recent reports have suggested that norepinephrine (NE) produces a form of synaptic enhancement that resembles long-term potentiation (LTP). The purpose of this study was to determine whether NE was capable of enhancing the phosphorylation of synapsin I and synapsin II, two homologous phosphoproteins thought to be involved in modulation of neurotransmitter release. We hypothesize that the beta-adrenergic agonist-stimulated phosphorylation of synapsin I and synapsin II in young rats plays a role in the increase in transmitter release produced by NE in the dentate. www.pdg.cnb.uam.es /UniPub/iHOP/gp/28493.html   (413 words)

Impairment of Inhibitory Synaptic Transmission in Mice Lacking Synapsin I -- Terada et al. 145 (5): 1039 -- The Journal ... Dephosphorylated synapsin I anchors synaptic vesicles to actin cytoskeleton: an analysis by videomicroscopy. Synapsin I and II are ATP-binding proteins with differential Ca regulation. Intraterminal injection of synapsin I or calcium/calmodulin-dependent protein kinase II alters neurotransmitter release at the squid giant synapse. www.jcb.org /cgi/content/full/145/5/1039   (5023 words)

Covance Research Products Online Store: Product Datasheet   (Site not responding. Last check: 2007-10-19) Synapsins are neuron-specific phosphoproteins that localize to the cytoplasmic face of small synaptic vesicles, with little or no expression in other tissues. Synapsin I is a specific marker of synapses throughout the nervous system. The synapsins are phosphoproteins that are substrates for several protein kinases such as PKA, CaMK I and CaMK II. store.crpinc.com /datasheet.aspx?catalogno=PRB-516P   (206 words)

Synapsin III: Developmental Expression, Subcellular Localization, and Role in Axon Formation -- Ferreira et al. 20 ... Synapsin III immunoreactivity was concentrated in cell bodies and growth cones (gc; arrowheads) in stage II and stage III cells. Synapsin III immunoreactivity was detectable along the axons (ax) and was highly concentrated in cell bodies and growth cones (gc) in sense-treated neurons. Baines AJ, Bennett V (1986) Synapsin I is a microtubule-bundling protein. www.jneurosci.org /cgi/content/full/20/10/3736   (4344 words)

A third member of the synapsin gene family -- Kao et al. 95 (8): 4667 -- Proceedings of the National Academy of Sciences Synapsins were first identified about 25 years ago as major substrates for cAMP-dependent protein kinase (1). Alignment of the exons of the human synapsin III gene with the bacterial artificial chromosomes bk415G2, the P1 artificial chromosome dJ309I22, and cosmids, N104C7, N80H12, E86D10, and N28H9, along chromosome 22. The location of synapsin III on the long arm of chromosome 22 is depicted in relationship to anonymous markers that map to 22q12.2 to 22q13.1. www.pnas.org /cgi/content/full/95/8/4667   (4383 words)

Computer Mathematical Simulation of the Dynamic Interactions   (Site not responding. Last check: 2007-10-19)      Synapsins constitute a group of three types of phosphoproteins that interact with synaptic vesicles and are a vital component in the regulation of neurotransmitter release. demonstrated that Synapsin I was able to form Synapsin-G actin complexes which caused actin to polymerize where spontaneous polymerization is neglibile; furthermore, this interaction is strongly affected by phosphorylation and dephosphorylation of synapsin.   Covalent modification of Synapsin I by a tetanus toxin-activated transglutaminase. robincmba.homeip.net /aboutme/synapsin   (5045 words)

NIDA - Director's Report - February 2003 Reduction of Synapsin in the Hippocampus of Patients with Bipolar Disorder and Schizophrenia Several studies suggest that decreased expression of presynaptic proteins may be characteristic of schizophrenia. Total synapsin was decreased significantly in patients with schizophrenia (P = 0.034) and in bipolar disorder (P = 0.00008) as compared to controls. Reductions in synapsin in both patients with schizophrenia (synapsin IIa and IIIa) and bipolar disorder (synapsin Ia, IIa and IIIa) imply that altered or reduced synaptic function in the hippocampus may be involved in these disorders. www.nida.nih.gov /DirReports/DirRep203/DirectorReport7.html   (5506 words)

Lehigh University Department of Biological Sciences Maria Bykhovskaia, William’s research focuses on how presynaptic proteins modulate the mechanisms that are thought to underlie learning and memory at the cellular level. Specifically, William is interested in how two presynaptic proteins (synapsin II and rab3a) function in the vesicle cycle in the mouse neuromuscular junction. Classically, synapsin II has been thought to interact with both synaptic vesicles and cytoskeletal filaments to create a reserve pool vesicles. www.lehigh.edu /~inbios   (462 words)

A role for Synapsin in associative learning: The Drosophila larva as a study case -- Michels et al. 12 (3): 224 -- ... Synapsin immunoreactivity is seen exclusively in boutons of wild-type CS (leftmost panel for wild-type CS in D), where it colocalizes with anti-HRP (right panel for wild-type CS in D). Chi, P., Greengard, P., and Ryan, T.A. Synaptic vesicle mobilization is regulated by distinct synapsin I phosphorylation pathways at different frequencies. Ferreira, A. and Rapoport, M. The synapsins: Beyond the regulation of neurotransmitter release. www.learnmem.org /cgi/content/full/12/3/224   (5126 words)

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