Synergistic regulation of fusion pore opening and dilation by SNARE and synaptotagmin-1

© The Author(s) 2024. Published by Oxford University Press on behalf of Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences..

Fusion pore opening is a transient intermediate state of synaptic vesicle exocytosis, which is highly dynamic and precisely regulated by the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and synaptotagmin-1 (Syt1). Yet, the regulatory mechanism is not fully understood. In this work, using single-channel membrane fusion electrophysiology, we determined that SNAREpins are important for driving fusion pore opening and dilation but incapable of regulating the dynamics. When Syt1 was added, the closing frequency of fusion pores significantly increased, while the radius of fusion pores mildly decreased. In response to Ca2+, SNARE/Syt1 greatly increased the radius of fusion pores and reduced their closing frequency. Moreover, the residue F349 in the C2B domain of Syt1, which mediates Syt1 oligomerization, was required for clamping fusion pore opening in the absence of Ca2+, probably by extending the distance between the two membranes. Finally, in Ca2+-triggered fusion, the primary interface between SNARE and Syt1 plays a critical role in stabilizing and dilating the fusion pore, while the polybasic region of Syt1 C2B domain has a mild effect on increasing the radius of the fusion pore. In summary, our results suggest that Syt1, SNARE, and the anionic membrane synergically orchestrate the dynamics of fusion pore opening in synaptic vesicle exocytosis.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - year:2024

Enthalten in:

Journal of molecular cell biology - (2024) vom: 05. März

Sprache:

Englisch

Beteiligte Personen:

Li, Kaiju [VerfasserIn]
Li, Kaiyu [VerfasserIn]
Fan, Jiaqi [VerfasserIn]
Zhang, Xing [VerfasserIn]
Tao, Chengyan [VerfasserIn]
Xiang, Yijuan [VerfasserIn]
Cui, Lele [VerfasserIn]
Li, Hao [VerfasserIn]
Li, Minghan [VerfasserIn]
Zhang, Yanjing [VerfasserIn]
Geng, Jia [VerfasserIn]
Lai, Ying [VerfasserIn]

Links:

Volltext

Themen:

Fusion pore
Journal Article
SNARE
Synaptotagmin-1
Vesicle exocytosis

Anmerkungen:

Date Revised 06.03.2024

published: Print-Electronic

Citation Status Publisher

doi:

10.1093/jmcb/mjae011

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369340108