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Models of synaptotagmin‐1 to trigger Ca 2+ ‐dependent vesicle fusion
Author(s) -
Park Yongsoo,
Ryu JeKyung
Publication year - 2018
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13193
Subject(s) - synaptotagmin 1 , vesicle fusion , vesicle , exocytosis , syt1 , snap25 , stx1a , lipid bilayer fusion , microbiology and biotechnology , synaptotagmin i , biology , synaptic vesicle , biophysics , chemistry , biochemistry , receptor , membrane , fibroblast growth factor , fgf10
Vesicles in neurons and neuroendocrine cells store neurotransmitters and peptide hormones, which are released by vesicle fusion in response to Ca 2+ ‐evoking stimuli. Synaptotagmin‐1 (Syt1), a Ca 2+ sensor, mediates ultrafast exocytosis in neurons and neuroendocrine cells. After vesicle docking, Syt1 has two main groups of binding partners: anionic phospholipids and the SNARE (soluble N ‐ethylmaleimide‐sensitive factor attachment protein receptors) complex. The molecular mechanisms by which Syt1 triggers vesicle fusion remain controversial. This Review introduces and summarizes six molecular models of Syt1: (a) Syt1 triggers SNARE unclamping by displacing complexin, (b) Syt1 clamps SNARE zippering, (c) Syt1 causes membrane curvature, (d) membrane bridging by Syt1, (e) Syt1 is a vesicle‐plasma membrane distance regulator, and (f) Syt1 undergoes circular oligomerization. We discuss important conditions to test Syt1 activity in vitro and attempt to illustrate the possible roles of Syt1.