Fusion pore formation and expansion induced by Ca2+ and synaptotagmin

Ying Lai, Jiajie Diao, Yanxin Liu, Yuji Ishitsuka, Zengliu Su, Klaus Schulten, Taekjip Ha, Yeon Kyun Shin

Research output: Contribution to journalArticle

Abstract

Fusion pore formation and expansion, crucial steps for neurotransmitter release and vesicle recycling in soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent vesicle fusion, have not been well studied in vitro due to the lack of a reliable content-mixing fusion assay. Using methods detecting the intervesicular mixing of small and large cargoes at a single-vesicle level, we found that the neuronal SNARE complexes have the capacity to drive membrane hemifusion. However, efficient fusion pore formation and expansion require synaptotagmin 1 and Ca2+. Real-time measurements show that pore expansion detected by content mixing of large DNA cargoes occurs much slower than initial pore formation that transmits small cargoes. Slow pore expansion perhaps provides a time window for vesicles to escape the full collapse fusion pathway via alternative mechanisms such as kissand- run. The results also show that complexin 1 stimulates pore expansion significantly, which could put bias between two pathways of vesicle recycling.

Original languageEnglish (US)
Pages (from-to)1333-1338
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number4
DOIs
StatePublished - Jan 22 2013

ASJC Scopus subject areas

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