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The stability of the primed pool of synaptic vesicles and the clamping of spontaneous neurotransmitter release rely on the integrity of the C-terminal half of the SNARE domain of syntaxin-1A.
Salazar Lázaro, Andrea; Trimbuch, Thorsten; Vardar, Gülçin; Rosenmund, Christian.
Affiliation
  • Salazar Lázaro A; Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.
  • Trimbuch T; Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.
  • Vardar G; Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.
  • Rosenmund C; Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.
Elife ; 122024 Mar 21.
Article in En | MEDLINE | ID: mdl-38512129
ABSTRACT
The SNARE proteins are central in membrane fusion and, at the synapse, neurotransmitter release. However, their involvement in the dual regulation of the synchronous release while maintaining a pool of readily releasable vesicles remains unclear. Using a chimeric approach, we performed a systematic analysis of the SNARE domain of STX1A by exchanging the whole SNARE domain or its N- or C-terminus subdomains with those of STX2. We expressed these chimeric constructs in STX1-null hippocampal mouse neurons. Exchanging the C-terminal half of STX1's SNARE domain with that of STX2 resulted in a reduced RRP accompanied by an increased release rate, while inserting the C-terminal half of STX1's SNARE domain into STX2 leads to an enhanced priming and decreased release rate. Additionally, we found that the mechanisms for clamping spontaneous, but not for Ca2+-evoked release, are particularly susceptible to changes in specific residues on the outer surface of the C-terminus of the SNARE domain of STX1A. Particularly, mutations of D231 and R232 affected the fusogenicity of the vesicles. We propose that the C-terminal half of the SNARE domain of STX1A plays a crucial role in the stabilization of the RRP as well as in the clamping of spontaneous synaptic vesicle fusion through the regulation of the energetic landscape for fusion, while it also plays a covert role in the speed and efficacy of Ca2+-evoked release.
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Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Synaptic Vesicles / Syntaxin 1 / Membrane Fusion Limits: Animals Language: En Journal: Elife Year: 2024 Document type: Article Affiliation country: Alemania

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Synaptic Vesicles / Syntaxin 1 / Membrane Fusion Limits: Animals Language: En Journal: Elife Year: 2024 Document type: Article Affiliation country: Alemania
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