Synaptotagmin-1: A Multi-Functional Protein that Mediates Vesicle Docking, Priming, and Fusion

Abstract

: The fusion of secretory vesicles with the plasma membrane depends on the assembly of v-SNAREs (VAMP2/synaptobrevin2) and t-SNAREs (SNAP25/syntaxin1) into the SNARE complex. Vesicles go through several upstream steps, referred to as docking and priming, to gain fusion competence. The vesicular protein synaptotagmin-1 (Syt-1) is the principal Ca2+ sensor for fusion in several central nervous system neurons and neuroendocrine cells and part of the docking complex for secretory granules. Syt-1 binds to the acceptor complex such as synaxin1, SNAP-25 on the plasma membrane to facilitate secretory vesicle docking, and upon Ca2+-influx promotes vesicle fusion. This review assesses the role of the Syt-1 protein involved in the secretory vesicle docking, priming, and fusion.

PACAP6-38 improves nitroglycerin-induced central sensitization by modulating synaptic plasticity at the trigeminal nucleus caudalis in a male rat model of chronic migraine

“…The syp is a marker protein of synaptic vesicles and is altered by synaptic dysfunction [ 46 ]. Syt-1 is a multifunctional protein producing vesicle docking, excitation, and fusion [ 47 ]. The results of immunoblotting showed that the expression of PSD95, syt-1, and syp was greatly increased in the NTG + VEH group compared with that in the saline + VEH group, while repeated treatment with PACAP6-38 markedly reduced the expression of these three proteins in the NTG + PA6-38 group ( p < 0.001; Fig.…”

Rab26 restricts insulin secretion via sequestering Synaptotagmin-1

“…Since Syt1 facilitates secretory vesicles docking to and fusion with plasma membrane through interaction with SNARE complex [ 25 ], we next examined whether Rab26 influences the interaction between Syt1 and SNARE complex. 293t cells were cotransfected with myc-Rab26 and GFP-SNAP25 or GFP-Syntaxin-1; the cell lysates were subjected for GST-pulldown using GST-Syt1.…”

“…J is the quantitative data from K. The images were performed with 4 mice pancreas in each of the 2 groups. (L) Western blot showed that Rab26 protein expression increased after 25…”

Microautophagy Mediates Vacuolar Delivery of Storage Proteins in Maize Aleurone Cells

“…The most important role of C2 domains is to activate membrane-associated protein modules in a Ca 2+dependent manner. Therefore, from this group, we selected GRMZM2G442551/Zm00001d046508, a putative phospholipase D alpha (annotated as phospholipase Dα5 in maize) with three C2 domains, GRMZM2G100864/Zm00001d036801, a predicted Ca 2+ -dependent lipid-binding phosphoribosyltransferase family protein with two C2 domains and whose putative Arabidopsis homologs, FTIP3 and 4 (FT INTERACTING PROOTEIN 3 and 4), are required for intracellular protein trafficking in meristematic tissues (Liu et al, 2018), and GRMZM2G050193/Zm00001d006238, which is a synaptotagmin-like protein and therefore potentially able to bind phospholipids, induce membrane curvature, and mediate contact sites between organelles (Ullah et al, 2021).…”