Non-SG fusion is SNARE dependent. (A) Two typical recordings from excised patches are shown. In the left panel, the amplitude is smaller than 50 fF, which is close to the artifact caused by moving the patch. Therefore, this patch is designated “inactive.” In the right panel, robust non-SG fusion (>50 fF) is observed in an “active” patch. (B) The same trace is fitted to a mono-exponential function (rate constant, k) with a linear “creep” component (c). (C) Incubation of patches with 200 nM tetanus toxin light chain (TeTx) for 2 min blocks fusion while the mutant toxin (E234Q) has no effect, indicating that non-SG fusion is SNARE dependent.