Block of transmitter release by botulinum C1 action on syntaxin at the squid giant synapse

Marsal, Jordi; Ruiz-Montasell, Bonaventura; Blasi, Juan; Moreira, Jorge E.; Contreras, Diego; Sugimori, Mutsuyuki; Llinás, Rodolfó R.

doi:10.1073/pnas.94.26.14871

Cited by 49 publications

(31 citation statements)

References 26 publications

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“…Indeed, this notion is supported by studies of the effects of botulinum toxin on the presynaptic terminals of the giant squid (36). This resulted in a 3-fold increase in the vesicular content of presynaptic terminals by interfering with the docking and͞or fusion properties of the synaptic proteins (i.e., synaptophysin, synaptobrevin, and synapsin I) and blocking the release of vesicles as well as their neurotransmitter contents (36)(37)(38). This toxin-induced accumulation of synaptic vesicles resembles that described in Fig.…”

Section: Discussionsupporting

confidence: 50%

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Axon pathology in Parkinson’s disease and Lewy body dementia hippocampus contains α-, β-, and γ-synuclein

Galvin

Uryu

Lee

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

405

305

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Pathogenic ␣-synuclein (␣S) gene mutations occur in rare familial Parkinson's disease (PD) kindreds, and wild-type ␣S is a major component of Lewy bodies (LBs) in sporadic PD, dementia with LBs (DLB), and the LB variant of Alzheimer's disease, but ␤-synuclein (␤S) and ␥-synuclein (␥S) have not yet been implicated in neurological disorders. Here we show that in PD and DLB, but not normal brains, antibodies to ␣S and ␤S reveal novel presynaptic axon terminal pathology in the hippocampal dentate, hilar, and CA2͞3 regions, whereas antibodies to ␥S detect previously unrecognized axonal spheroid-like lesions in the hippocampal dentate molecular layer. The aggregation of other synaptic proteins and synaptic vesicle-like structures in the ␣S-and ␤S-labeled hilar dystrophic neurites suggests that synaptic dysfunction may result from these lesions. Our findings broaden the concept of neurodegenerative ''synucleinopathies'' by implicating ␤S and ␥S, in addition to ␣S, in the onset͞progression of PD and DLB.perforant pathway ͉ mossy fibers T he synucleins are a family of soluble presynaptic proteins that are abundant in neurons and include ␣-synuclein (␣S) (also known as the nonamyloid component of plaques precursor protein or NACP) (1, 2), ␤-synuclein (␤S) (also known as phosphoneuroprotein 14 or PNP14) (3, 4), and ␥-synuclein (␥S) (also known as breast cancer-specific gene 1 or BCSG1 and persyn) (5, 6). Although they are homologous, each synuclein is encoded by a different gene on chromosomes 4q21.3-q22 (␣S) (7, 8), 5q35 (␤S) (9), and 10q23 (␥S) (10).The functions of synucleins are poorly understood; however, mutations in the ␣S gene are linked to familial Parkinson's disease (PD) in rare kindreds (11,12). ␣S is a major component of Lewy bodies (LBs) and Lewy neurites in sporadic PD, dementia with LBs (DLB) and a subtype of Alzheimer's disease (AD) with abundant neocortical LBs known as the LB variant of AD (13-15). Further, LBs have been described in familial AD caused by presenilin and amyloid precursor protein gene mutations (16) and Down's syndrome (17). In addition, ␣S is a major component of glial cytoplasmic inclusions (GCIs) in multiple system atrophy (MSA) (18, 19) as well as the neuronal inclusions and GCIs in Hallervorden-Spatz disease (18). Heretofore, ␤S and ␥S have not been implicated in neurodegenerative disease (15, 18), although ␥S may play a role in breast cancer progression (5).Here, we report the identification of axonal pathology with antibodies to ␤S and ␥S in the hippocampus of PD and DLB brains, but not in control brains, thereby implicating ␤S and ␥S, in addition to ␣S, in neurodegenerative disease. MethodsCase Materials. Brains of autopsy proven PD (n ϭ 5), DLB (n ϭ 5), AD (n ϭ 5), MSA (n ϭ 2), Pick's disease (n ϭ 2), and normal controls (n ϭ 5) were examined and compared after postmortem assessment in the Center for Neurodegenerative Disease Research at the University of Pennsylvania School of Medicine to establish a neuropathological diagnosis in each case (15-18, 20).Immunohistochemistry. Immu...

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Section: Discussionsupporting

confidence: 50%

“…4. Thus, the aggregation of synucleinlabeled vesicles and filaments in presynaptic terminals might reflect impaired synaptic vesicle release and synaptic dysfunction (36). Similar impairments also could result from the ␥S pathol- ogy localized to the molecular layer of the dentate gyrus (see Fig.…”

Section: Discussionmentioning

confidence: 93%

Axon pathology in Parkinson’s disease and Lewy body dementia hippocampus contains α-, β-, and γ-synuclein

Galvin

Uryu

Lee

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

405

305

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“…These observations suggest that the BoNT-C1-induced block in cell division is the result of the syntaxin-targeted toxin activity. BoNT-C1 blocks synaptic vesicle fusion in the neuron by cleaving syntaxin, resulting in an accumulation of synaptic vesicles at the active zone of the synapse (Marsal et al, 1997;O'Connor et al, 1997). However, we suspected that in the rapidly dividing sea urchin embryo with a single syntaxin homologue that injection of BoNT-C1 could result in major changes in membrane topology of the cell that would lead to the block in cell division.…”

mentioning

confidence: 80%

Syntaxin Is Required for Cell Division

Conner

Wessel

1999

MBoC

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We recently identified a single family member homologue of syntaxin in the sea urchin. Syntaxin is present throughout development, and in rapidly dividing cleavage stage embryos it is present on numerous vesicles at the cell cortex. We hypothesized that syntaxin mediates essential membrane fusion events during early embryogenesis, reasoning that the vesicles and/or their contents are important for development. Here we show that functional inactivation of syntaxin with either Botulinum neurotoxin C1, which specifically proteolyzes syntaxin, or antibodies against syntaxin results in an inhibition of cell division. These observations suggest that syntaxin is essential for membrane fusion events critical for cell division. INTRODUCTIONCell division is a highly coordinated event requiring a variety of membrane fusion and fragmentation events. During mitosis in higher eukaryotes, for example, the nuclear envelope breaks down into nuclear membrane vesicles after chromosome condensation, and large cytoplasmic organelles such as the Golgi and endoplasmic reticulum (ER) are also believed to fragment (Lucocq and Warren, 1987;Warren, 1989). These fragmented organelle membranes then distribute equally into daughter cells and must refuse with each other to reconstitute their respective organelles. In addition to the breakdown and reformation of the nuclear envelope, Golgi, and ER during the cell cycle, the cell also increases its membrane surface area during cell division (for review, see Rappaport, 1996).What proteins mediate these essential membrane fusion events during cell division? A highly conserved set of membrane proteins have been identified that are involved in many types of intracellular fusion (Rothman, 1994;Sudhof, 1995). These proteins localize to both vesicle and target membranes, known as v-and t-soluble NSF attachment protein (SNAP) receptors (SNAREs), respectively, and appear to function throughout the secretory pathway as the minimal machinery driving membrane fusion (Fasshauer et al., 1998;Weber et al., 1998). Recently, single family member homologues of syntaxin (t-SNARE), vesicle-associated membrane protein (VAMP; v-SNARE), and the monomeric GTPbinding protein rab3 were identified in the sea urchin egg in association with cortical granules, secretory vesicles whose contents give rise to the fertilization envelope (Conner et al., 1997). Syntaxin, VAMP, and rab3 are also present throughout embryogenesis enriched in cells with elevated levels of regulated secretion (Conner and Wessel, manuscript in preparation). During the cleavage stage of this embryo, a period of cell division every 45-60 min, we find enrichment of these molecules on vesicles accumulating at the cortex of cells, suggesting that these vesicles may play an important role in cell division. Thus, we hypothesized that these proteins not only mediate the complex array of membrane fusion events of secretion, as previously documented (for review, see Ferro-Novick and Jahn, 1994;Rothman and Sollner, 1997), but also function in the contribution o...

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“…An obvious interacting protein on the plasma membrane is syntaxin, and data from yeast indicate that UNC-18 could act in SNARE preassembly 41 . However, data from Drosophila melanogaster and squid indicate that syntaxin is not required for docking 31,42,43 . Furthermore, additional factors at the plasma membrane would be required, since UNC-18 and syntaxin are not restricted to active zones 8,44,45 .…”

Section: Models For Unc-18 Functionmentioning

confidence: 99%

Defects in synaptic vesicle docking in unc-18 mutants

et al. 2003

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Sec1-related proteins function in most, if not all, membrane trafficking pathways in eukaryotic cells. The Sec1-related protein required in neurons for synaptic vesicle exocytosis is UNC-18. Several models for UNC-18 function during vesicle exocytosis are under consideration. We have tested these models by characterizing unc-18 mutants of the nematode Caenorhabditis elegans. In the absence of UNC-18, the size of the readily releasable pool is severely reduced. Our results show that the near absence of fusion-competent vesicles is not caused by a reduction in syntaxin levels, by a mislocalization of syntaxin, by a defect in fusion or by a failure to open syntaxin during priming. Rather, we found a reduction of docked vesicles at the active zone in unc-18 mutants, suggesting that UNC-18 functions, directly or indirectly, as a facilitator of vesicle docking.Synaptic vesicles must be tethered to sites of release and then become competent for fusion with the plasma membrane. These processes are called docking and priming, respectively 1 . The molecular processes of docking are not well understood. Priming appears to involve the formation of trans-SNARE complexes, in which the synaptic vesicle protein synaptobrevin (also called VAMP) forms a helical bundle with the plasma membrane proteins syntaxin and . The formation of SNARE complexes is sufficient for membrane fusion in vitro 3 , but may require other components in vivo 4,5 .Another protein that is involved in synaptic vesicle exocytosis is . unc-18 mutants were first isolated in C. elegans on the basis of their severe locomotion defects 7 . The UNC-18 protein is similar to the yeast SEC1 protein 8 , and orthologs of UNC-18 function at the synapses of fruit flies (Rop) 9 and vertebrates (Muncl8-1; also known as Stxbpl, N-secl, Rb-secl) 10 . Genetic studies of UNC-18 in various organisms suggest that UNC-18 is required for synaptic vesicle exocytosis. For example, unc-18 mutants in C. elegans are severely paralyzed and are resistant to inhibitors of cholinesterase but sensitive to acetylcholine (ACh) receptor agonists 11 , implicating UNC-18 in the exocytosis of ACh.

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Block of transmitter release by botulinum C1 action on syntaxin at the squid giant synapse

Cited by 49 publications

References 26 publications

Axon pathology in Parkinson’s disease and Lewy body dementia hippocampus contains α-, β-, and γ-synuclein

Axon pathology in Parkinson’s disease and Lewy body dementia hippocampus contains α-, β-, and γ-synuclein

Syntaxin Is Required for Cell Division

Defects in synaptic vesicle docking in unc-18 mutants

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