| Abstract No.: | 206 |
| Country: | Canada |
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| Title: | The Transmitter Release Site Organelle |
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| Authors/Affiliations: | Elise F. Stanley
Toronto Western Research Institute, Divisions of Genetics & Development, Toronto, ON, Canada |
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| Content: | The rapid release of neurotransmitters from nerve terminals at synapses occurs at specialized areas on the presynaptic transmitter release face opposing postsynaptic receptor regions that are described morphologically as active zones. Presynaptic Ca2+ channels play a crucial role by admitting the Ca2+ ions that bind to and gate secretory vesicle fusion and discharge. Functional, biochemical, morphological and ultrastructural evidence suggest that the Ca2+ channel is an integral element of the transmitter release apparatus. Our recent studies have used proteomic, immunocytochemical, electrophysiological and novel biochemical approaches to analyze the composition and functional organization of the transmitter release site megacomplex. This work suggests that the transmitter release site includes not only the secretory vesicle and its docking/fusion mechanisms but also an associated endocytosis complex and accessory trans-synaptic bridging proteins and is a key element of the active zone. This complex appears to interact with independent complexes for vesicle supply and refilling. We argue transmitter release site should be regarded as a cell organelle that is specialized for the docking, fusion and recovery of secretory vesicles under tight temporal control. |
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