The interaction of Munc18-1 Helix 11 and 12 with the central region of the VAMP2 SNARE motif is essential for SNARE templating and synaptic transmission

Timon André, Jessica Classen, Philipp Brenner, Matthew J. Betts, Bernhard Dörr, Susanne Kreye, Birte Zuidinga, Marieke Meijer, Robert B. Russell, Matthijs Verhage, Thomas H. Söllner*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Sec1/Munc18 proteins play a key role in initiating the assembly of N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes, the molecular fusion machinery. Employing comparative structure modeling, site specific crosslinking by single amino acid substitutions with the photoactivatable unnatural amino acid p-Benzoyl-phenylalanine (Bpa) and reconstituted vesicle docking/fusion assays, we mapped the binding interface between Munc18-1 and the neuronal v-SNARE VAMP2 with single amino acid resolution. Our results show that helices 11 and 12 of domain 3a in Munc18-1 interact with the VAMP2 SNARE motif covering the region from layers-4 to 15. Residue Q301 in helix 11 plays a pivotal role in VAMP2 binding and template complex formation. A VAMP2 binding deficient mutant, Munc18-1 Q301D, does not stimulate lipid mixing in a reconstituted fusion assay. The neuronal SNARE-organizer Munc13-1, which also binds VAMP2, does not bypass the requirement for the Munc18-1.VAMP2 interaction. Importantly, Munc18-1 Q301D expression in Munc18-1 deficient neurons severely reduces synaptic transmission, demonstrating the physiological significance of the Munc18-1.VAMP2 interaction.

Original languageEnglish
Article numberENEURO.0278-20.2020
Pages (from-to)1-5
Number of pages5
JournaleNeuro
Volume7
Issue number6
DOIs
Publication statusPublished - 1 Nov 2020

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