Syntaxin and synaptobrevin function downstream of vesicle docking in drosophila

Broadie, Kendal; Prokop, Andreas; Bellen, Hugo J.; O’Kane, Cahir J.; Schulze, Karen L.; Sweeney, Sean T.

doi:10.1016/0896-6273(95)90154-x

Cited by 360 publications

(280 citation statements)

References 50 publications

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“…The present and other results [22,27] raise a question regarding the docking model of vesicles with target membranes, which is based on the different localization of t-and v-SNAREs. It was recently suggested that VAMP-2 and syntaxin play roles after the docking of synaptic vesicles at the active zone of the plasma membrane [39]. …”

Section: Discussionmentioning

confidence: 99%

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

et al. 1996

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SNAP-25 is located on the plasma membrane and essential for exocytosis of neurotransmitters. It was suggested that SNAP-25 and syntaxin 1 via the interaction with VAMP-2 located on synaptic vesicles mediate the docking of the vesicles with the plasma membrane. In the present study, by means of biochemical and morphological analyses, we showed that SNAP-25 is present on chromaffin granules as well as on the plasma membrane. Reconstitution and immunoprecipitation analyses revealed that SNAP-25 on chromaffin granules has essentially the same properties as does SNAP-25 on the plasma membrane.

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Section: Discussionmentioning

confidence: 99%

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

et al. 1996

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“…This apparent dual function for Rop can be reconciled by the observation that Rop expression does not alter the number of docked vesicles at the synapse, implying at least some postdocking function for Rop (55). Similarly, in addition to vesicle docking, syntaxin has also been shown to play a post-docking role and, in sole combination with SNAP25 and VAMP, is sufficient to reconstitute membrane fusion (57,58).…”

Section: Discussionmentioning

confidence: 99%

Regulation of Insulin-stimulated GLUT4 Translocation by Munc18c in 3T3L1 Adipocytes

Thurmond¹,

Ceresa²,

Okada

et al. 1998

Journal of Biological Chemistry

216

237

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Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2-and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co-immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.The binding of insulin to its heterotetrameric integral-membrane receptor activates its intracellular tyrosine kinase domain and thereby triggers a signaling cascade resulting in the translocation and fusion of intracellular GLUT4 1 isoform-containing vesicles to the plasma membrane (1-3). Although most cell types also constitutively express the GLUT1 isoform at the cell surface, the insulin-stimulated increase in plasma membrane-associated GLUT4 protein accounts for the majority of post-prandial glucose disposal in both muscle and adipose tissue (4).The insulin-stimulated translocation of these GLUT4-containing vesicles has several features in common with the regulated exocytosis pathway of synaptic vesicle trafficking in neurotransmitter release (5). The machinery involved in the regulation of synaptic vesicle priming/docking/fusion entails the pairing of protein complexes in the vesicle compartment (v-SNAREs, for vesicle SNAP receptors) with their cognate receptor complexes at the target membrane (t-SNAREs, for target membrane SNAP receptors). Recently, several of the vand t-SNARE proteins have been identified that specifically participate in the insulin-regulated docking and fusion of GLUT4 vesicles with the adipocyte plasma membrane. GLUT4 vesicles co-purify with both the VAMP2 and VAMP3 v-SNARE isoforms and specific proteolytic cleavage of VAMP2, expression of a dominant-interfering VAMP2 mutant or inhibitory peptides impairs insulin-stimulated GLUT4 translocation (6 -11). In addition, transferrin-horseradish peroxidase ablation of recycling endosomes resulted in a selective loss ...

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“…Key proteins that act in Ca2+-regulated exocytosis in neurons and endocrine cells include the vesicle proteins synaptotagmin [1] and VAMP/synaptobrevin [2,3], the plasma membrane proteins syntaxin [4] and SNAP-25 [5] and, in addition, the soluble N-ethylmaleimide-sensitive fusion protein (NSF) [16] and soluble NSF-attachment proteins (c~-, 13-and ySNAPs) [7] Functional evidence for the importance of the membrane proteins has come from their sensitivity to the specific proteolytic actions of clostridial neurotoxins [8,9] and/or genetic analysis in mice and Drosophila [10][11][12]. The soluble factors NSF and SNAP were found to interact, in a 20S complex, with the neurotoxin substrates leading to them being designated as SNAP-receptors (SNARE) [13,14].…”

Section: Introductionmentioning

confidence: 99%

Similar effects of α‐ and β‐SNAP on Ca ²⁺‐regulated exocytosis

et al. 1996

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We have examined this possibility by comparing the activities of recombinant a-and ~SNAPs. Both of these proteins were able to similarly bind NSF and activate its ATPase activity but to a lesser extent than y-SNAP. When introduced into digitoninpermeabilised chromaffin cells, both a-and J~-SNAP stimulated Ca2+-regulated exocytosis in a MgATP-dependent manner. The dose-response relationships for these proteins were essentially the same and addition of both proteins did not lead to any further increase in exocytosis above that due to each protein alone. We conclude that a-and/]-SNAPs are interchangeable isoforms with similar functions in regulated exocytosis.

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Syntaxin and synaptobrevin function downstream of vesicle docking in drosophila

Cited by 360 publications

References 50 publications

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

Regulation of Insulin-stimulated GLUT4 Translocation by Munc18c in 3T3L1 Adipocytes

Similar effects of α‐ and β‐SNAP on Ca ²⁺‐regulated exocytosis

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Syntaxin and synaptobrevin function downstream of vesicle docking in drosophila

Cited by 360 publications

References 50 publications

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

SNAP‐25 is present on chromaffin granules and acts as a SNAP receptor

Regulation of Insulin-stimulated GLUT4 Translocation by Munc18c in 3T3L1 Adipocytes

Similar effects of α‐ and β‐SNAP on Ca 2+‐regulated exocytosis

Contact Info

Product

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Similar effects of α‐ and β‐SNAP on Ca ²⁺‐regulated exocytosis