BIOLOGY 2C03 Lecture Notes - Synaptic Vesicle, Synaptotagmin 1, Lipid Bilayer Fusion
Document Summary
Role of synaptic vesicles: release nxt onto presynaptic membrane upon stimulation (ca++), in a way relatively autonomously from cell body. Sv lifecycle: sv formation (direct endocytosis or endosomal), nxt loading, docking, priming, fusion, endocytosis (and possible delivery to endosomes) See p. 5 for list of sv properties (size and composition) There are lots of proteins and subtypes involved in sv, we will focus on a key few. Localization in nerve terminal: e. g. synapsins, rabs. Transport across sv membrane: e. g. pumps, transporters, sv2. General model of vesicle docking and fusion: 7s complex. Made of synaptotagmin and vamp on vesicle and synatxin and snap-25 on synapse. Forms a very tight complex in a 4-helix bundle. A model proposed in 1994 implicates these proteins as central to membrane fusion: the other complexes. Core complex = vamp + synatxin + snap-25. 7s complex = core complex + synaptotagmin. Snare hypothesis says that targeting specifity mediated by v-snare (e. g. vamp) and t-