Cargando…

Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis

Ca(2+)-triggered SNARE-mediated membrane fusion is essential for neuronal communication. The speed of this process is of particular importance because it sets a time limit to cognitive and physical activities. In this work, we expand the proteoliposome-to-supported bilayer (SBL) fusion assay by succ...

Descripción completa

Detalles Bibliográficos
Autores principales: Kim, Jaewook, Shin, Yeon-Kyun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695160/
https://www.ncbi.nlm.nih.gov/pubmed/29187811
http://dx.doi.org/10.3389/fnmol.2017.00380
_version_ 1783280262778454016
author Kim, Jaewook
Shin, Yeon-Kyun
author_facet Kim, Jaewook
Shin, Yeon-Kyun
author_sort Kim, Jaewook
collection PubMed
description Ca(2+)-triggered SNARE-mediated membrane fusion is essential for neuronal communication. The speed of this process is of particular importance because it sets a time limit to cognitive and physical activities. In this work, we expand the proteoliposome-to-supported bilayer (SBL) fusion assay by successfully incorporating synaptotagmin 1 (Syt1), a major Ca(2+) sensor. We report that Syt1 and Ca(2+) together can elicit more than a 50-fold increase in the number of membrane fusion events when compared with membrane fusion mediated by SNAREs only. What is remarkable is that ~55% of all vesicle fusion events occurs within 20 ms upon vesicle docking. Furthermore, pre-binding of Syt1 to SNAREs prior to Ca(2+) inhibits spontaneous fusion, but intriguingly, this leads to a complete loss of the Ca(2+) responsiveness. Thus, our results suggest that there is a productive and a non-productive pathway for Syt1, depending on whether there is a premature interaction between Syt1 and SNAREs. Our results show that Ca(2+) binding to Syt1 prior to Syt1's binding to SNAREs may be a prerequisite for the productive pathway. The successful reconstitution of Syt1 activities in the physiological time scale provides new opportunities to test the current mechanistic models for Ca(2+)-triggered exocytosis.
format Online
Article
Text
id pubmed-5695160
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-56951602017-11-29 Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis Kim, Jaewook Shin, Yeon-Kyun Front Mol Neurosci Neuroscience Ca(2+)-triggered SNARE-mediated membrane fusion is essential for neuronal communication. The speed of this process is of particular importance because it sets a time limit to cognitive and physical activities. In this work, we expand the proteoliposome-to-supported bilayer (SBL) fusion assay by successfully incorporating synaptotagmin 1 (Syt1), a major Ca(2+) sensor. We report that Syt1 and Ca(2+) together can elicit more than a 50-fold increase in the number of membrane fusion events when compared with membrane fusion mediated by SNAREs only. What is remarkable is that ~55% of all vesicle fusion events occurs within 20 ms upon vesicle docking. Furthermore, pre-binding of Syt1 to SNAREs prior to Ca(2+) inhibits spontaneous fusion, but intriguingly, this leads to a complete loss of the Ca(2+) responsiveness. Thus, our results suggest that there is a productive and a non-productive pathway for Syt1, depending on whether there is a premature interaction between Syt1 and SNAREs. Our results show that Ca(2+) binding to Syt1 prior to Syt1's binding to SNAREs may be a prerequisite for the productive pathway. The successful reconstitution of Syt1 activities in the physiological time scale provides new opportunities to test the current mechanistic models for Ca(2+)-triggered exocytosis. Frontiers Media S.A. 2017-11-15 /pmc/articles/PMC5695160/ /pubmed/29187811 http://dx.doi.org/10.3389/fnmol.2017.00380 Text en Copyright © 2017 Kim and Shin. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Kim, Jaewook
Shin, Yeon-Kyun
Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title_full Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title_fullStr Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title_full_unstemmed Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title_short Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca(2+)-Triggered Fast Exocytosis
title_sort productive and non-productive pathways for synaptotagmin 1 to support ca(2+)-triggered fast exocytosis
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695160/
https://www.ncbi.nlm.nih.gov/pubmed/29187811
http://dx.doi.org/10.3389/fnmol.2017.00380
work_keys_str_mv AT kimjaewook productiveandnonproductivepathwaysforsynaptotagmin1tosupportca2triggeredfastexocytosis
AT shinyeonkyun productiveandnonproductivepathwaysforsynaptotagmin1tosupportca2triggeredfastexocytosis