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Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion
In the neuron, neurotransmitter release is an essential function that must be both consistent and tightly regulated. The continuity of neurotransmitter release is dependent in large part on vesicle recycling. However, the protein factors that dictate the vesicle recycling pathway are elusive. Here,...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8712692/ https://www.ncbi.nlm.nih.gov/pubmed/34970598 http://dx.doi.org/10.3389/fmolb.2021.805000 |
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author | Pierson, Josh Shin, Yeon-Kyun |
author_facet | Pierson, Josh Shin, Yeon-Kyun |
author_sort | Pierson, Josh |
collection | PubMed |
description | In the neuron, neurotransmitter release is an essential function that must be both consistent and tightly regulated. The continuity of neurotransmitter release is dependent in large part on vesicle recycling. However, the protein factors that dictate the vesicle recycling pathway are elusive. Here, we use a single vesicle-to-supported bilayer fusion assay to investigate complexin-1 (cpx1)’s influence on SNARE-dependent fusion pore expansion. With total internal reflection (TIR) microscopy using a 10 kDa polymer fluorescence probe, we are able to detect the presence of large fusion pores. With cpx1, however, we observe a significant increase of the probability of the formation of large fusion pores. The domain deletion analysis reveals that the SNARE-binding core domain of cpx1 is mainly responsible for its ability to promote the fusion pore expansion. In addition, the results show that cpx1 helps the pore to expand larger, which results in faster release of the polymer probe. Thus, the results demonstrate a reciprocal relationship between event duration and the size of the fusion pore. Based on the data, a hypothetical mechanistic model can be deduced. In this mechanistic model, the cpx1 binding stabilizes the four-helix bundle structure of the SNARE core throughout the fusion pore expansion, whereby the highly curved bilayer within the fusion pore is stabilized by the SNARE pins. |
format | Online Article Text |
id | pubmed-8712692 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-87126922021-12-29 Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion Pierson, Josh Shin, Yeon-Kyun Front Mol Biosci Molecular Biosciences In the neuron, neurotransmitter release is an essential function that must be both consistent and tightly regulated. The continuity of neurotransmitter release is dependent in large part on vesicle recycling. However, the protein factors that dictate the vesicle recycling pathway are elusive. Here, we use a single vesicle-to-supported bilayer fusion assay to investigate complexin-1 (cpx1)’s influence on SNARE-dependent fusion pore expansion. With total internal reflection (TIR) microscopy using a 10 kDa polymer fluorescence probe, we are able to detect the presence of large fusion pores. With cpx1, however, we observe a significant increase of the probability of the formation of large fusion pores. The domain deletion analysis reveals that the SNARE-binding core domain of cpx1 is mainly responsible for its ability to promote the fusion pore expansion. In addition, the results show that cpx1 helps the pore to expand larger, which results in faster release of the polymer probe. Thus, the results demonstrate a reciprocal relationship between event duration and the size of the fusion pore. Based on the data, a hypothetical mechanistic model can be deduced. In this mechanistic model, the cpx1 binding stabilizes the four-helix bundle structure of the SNARE core throughout the fusion pore expansion, whereby the highly curved bilayer within the fusion pore is stabilized by the SNARE pins. Frontiers Media S.A. 2021-12-14 /pmc/articles/PMC8712692/ /pubmed/34970598 http://dx.doi.org/10.3389/fmolb.2021.805000 Text en Copyright © 2021 Pierson and Shin. https://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) and the copyright owner(s) 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 | Molecular Biosciences Pierson, Josh Shin, Yeon-Kyun Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title | Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title_full | Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title_fullStr | Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title_full_unstemmed | Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title_short | Stabilization of the SNARE Core by Complexin-1 Facilitates Fusion Pore Expansion |
title_sort | stabilization of the snare core by complexin-1 facilitates fusion pore expansion |
topic | Molecular Biosciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8712692/ https://www.ncbi.nlm.nih.gov/pubmed/34970598 http://dx.doi.org/10.3389/fmolb.2021.805000 |
work_keys_str_mv | AT piersonjosh stabilizationofthesnarecorebycomplexin1facilitatesfusionporeexpansion AT shinyeonkyun stabilizationofthesnarecorebycomplexin1facilitatesfusionporeexpansion |