A Fast Mode of Membrane Fusion Dependent on Tight SNARE Zippering
| Autor: | Marine Bretou, François Darchen, Christine Anne |
|---|---|
| Přispěvatelé: | Biologie cellulaire et moléculaire de la sécrétion (BCMS), Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2008 |
| Předmět: |
Time Factors
Vesicle-Associated Membrane Protein 2 Chromaffin Cells Amino Acid Motifs Membrane Fusion MESH: Amino Acid Motifs MESH: Protein Structure Tertiary MESH: Osmolar Concentration 0302 clinical medicine MESH: Chromaffin Cells MESH: Animals Cells Cultured MESH: Vesicle-Associated Membrane Protein 2 MESH: Exocytosis 0303 health sciences Fusion MESH: Electrophysiology MESH: Adrenal Medulla General Neuroscience SNAP25 Articles Cell biology Electrophysiology MESH: Cattle MESH: Intracellular Membranes Transmembrane domain Membrane MESH: Calcium Porosome Intracellular MESH: Cells Cultured MESH: Probability Biology Transfection MESH: Membrane Fusion Exocytosis 03 medical and health sciences Animals Point Mutation [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology Probability MESH: Point Mutation 030304 developmental biology MESH: Transfection Osmolar Concentration MESH: Time Factors Lipid bilayer fusion Intracellular Membranes Protein Structure Tertiary Mutagenesis Insertional MESH: Mutagenesis Insertional Adrenal Medulla Calcium Cattle 030217 neurology & neurosurgery |
| Zdroj: | Journal of Neuroscience Journal of Neuroscience, Society for Neuroscience, 2008, 28 (34), pp.8470-6. ⟨10.1523/JNEUROSCI.0860-08.2008⟩ |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.0860-08.2008 |
| Popis: | SNARE (solubleN-ethylmaleimide-sensitive factor attachment protein receptor) proteins have a key role in membrane fusion. It is commonly assumed that pairing of SNARE proteins anchored in opposing membranes overcomes the repulsion energy between membranes, thereby catalyzing fusion. In this study, we have increased the distance between the coiled-coil SNARE motif and the transmembrane domain of the vesicular SNARE synaptobrevin-2 by insertion of a flexible linker to analyze how an increased intermembrane distance affects exocytosis. Synaptobrevin-2 lengthening did not change the frequency of exocytotic events measured at 1 μmfree calcium but prevented the increase in the secretory activity triggered by higher calcium concentration. Exocytotic events monitored in adrenal chromaffin cells by means of carbon fiber amperometry were classified in two groups according to the rate and extent of fusion pore expansion. Lengthening the juxtamembrane region of synaptobrevin-2 severely reduced the occurrence of rapid single events, leaving slow ones unchanged. It also impaired the increase in the fast-fusion mode that normally follows elevation of intracellular Ca2+levels. We conclude that mild stimuli trigger slow fusion events that do not rely on a short intermembrane distance. In contrast, a short intermembrane distance mediated by tight zippering of SNAREs is essential to a component of the secretory response elicited by robust stimuli and characterized by rapid dilation of the fusion pore. |
| Databáze: | OpenAIRE |
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