RT Journal Article SR Electronic T1 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 JF eneuro JO eNeuro FD Society for Neuroscience SP ENEURO.0278-20.2020 DO 10.1523/ENEURO.0278-20.2020 A1 Timon André A1 Jessica Classen A1 Philipp Brenner A1 Matthew Betts A1 Bernhard Dörr A1 Susanne Kreye A1 Birte Zuidinga A1 Marieke Meijer A1 Robert B. Russell A1 Matthijs Verhage A1 Thomas H. Söllner YR 2020 UL http://www.eneuro.org/content/early/2020/10/14/ENEURO.0278-20.2020.abstract AB 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 benzoylphenylalanine (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 +5. 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.Significance Statement Reliable neurotransmitter release depends on the precisely controlled Ca2+-synchronized fusion of synaptic vesicles with the presynaptic plasma membrane. This requires the correct assembly of the molecular membrane fusion machinery, N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes, by Sec1/Munc18 proteins. In this study, we establish a map with single amino acid precision of how Munc18-1 provides a template for the binding of the v-SNARE protein VAMP2 and demonstrate its relevance for synaptic function.