TY - JOUR 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 DO - 10.1523/ENEURO.0278-20.2020 VL - 7 IS - 6 SP - ENEURO.0278-20.2020 AU - Timon André AU - Jessica Classen AU - Philipp Brenner AU - Matthew J. Betts AU - Bernhard Dörr AU - Susanne Kreye AU - Birte Zuidinga AU - Marieke Meijer AU - Robert B. Russell AU - Matthijs Verhage AU - Thomas H. Söllner Y1 - 2020/11/01 UR - http://www.eneuro.org/content/7/6/ENEURO.0278-20.2020.abstract N2 - 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 +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. ER -