Ca2+-free synaptotagmin-1 binds to neuronal SNARE complexes anchored on nanodiscs, and Ca2+ releases this interaction to induce tight, specific binding to PIP2-containing membranes.
Travis J Eisemann, Frederick Allen ... Frederick M Hughson
Whereas in a paradigmatic structure an SM protein chaperone clamps its client SNARE shut, a second structure demonstrates that an SM protein can also hold its SNARE open to promote assembly.
Novel insights into the molecular mechanisms underlying neurotransmitter release are provided by all-atom molecular dynamics simulations including SNARE proteins, synaptotagmin-1, complexin-1, a vesicle and a flat bilayer.
Daniëlle Rianne José Verboogen, Natalia González Mancha ... Geert van den Bogaart
A novel microscopy-based assay shows that dendritic cells encountering pathogenic stimuli form increased complexes of specific SNARE proteins, driving release of large amounts of inflammatory cytokines.
The tethering complex HOPS employs affinity for each of the 4 SNAREs to catalyze assembly of 3-SNARE intermediates, supporting an immediate burst of membrane fusion triggered by the 4th SNARE.
Braden T Lobingier, Daniel P Nickerson ... Alexey J Merz
Sec1/Munc18 (SM) proteins shield SNARE complexes from NSF/Sec18-mediated disassembly through cooperative binding interactions with SNARE complexes and the universal co-chaperone α-SNAP/Sec17.
The ability of COPI to bind polyubiquitin is a key determinant for SNARE incorporation into intracellular vesicles and for maintenance of a functional Golgi complex.
A few SNARE complexes suffice to fuse membranes, but many more are needed to dilate the nascent fusion pore by molecular crowding for efficient neurotransmitter or hormone release during exocytosis.