Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2047843 | FEBS Letters | 2013 | 6 Pages |
Synaptobrevin 2 (Syb2), syntaxin (Sx1A), and SNAP-25, generate a force to induce fusion pore formation. The v-SNARE, Syb2, is anchored to the vesicle membrane by a single transmembrane domain. Here we show that 2 tryptophans (W89/W90) located in the juxtamembrane domain of Syb2, which stabilize the transmembrane (TM) domain position, control the ratio of spontaneous vs. stimulated membrane fusion events in chromaffin cells. Changing the 2 hydrophobic tryptophans to neutral alanines promotes spontaneous membrane fusion, faster transmitter release kinetics and complete release from individual vesicles. The results indicate that the two tryptophans act as a fusion clamp making fusion stimulus-dependent.
► Tryptophan pair (W89/W90) of synaptobrevin acts as a fusion clamp in chromaffin cells. ► W89AW90A mutant increases spontaneous release frequency. ► W89AW90A mutant produces increased quantal size of single release events.