Membrane fusion between liposomes containing SNARE proteins involved in mast cell exocytosis

Abstract.

Objective and design:

We monitored the membrane fusion of liposomes to determine if the minimal components of soluble N-ethyl maleimide-sensitive factor attachment protein receptor (SNARE), which is involved in mast cell exocytosis, have fusogenic activity.

Methods:

Three core components of SNARE were reconstituted into liposomes. Membrane fusion between liposomes containing vesicle associated membrane protein (VAMP) -7 or -8 and liposomes containing synaptosomal-associated protein 23 kDa (SNAP23) and syntaxin-3 or -4 was monitored by fluorescence resonance energy transfer.

Results:

The combination of SNAP23/syntaxin-3/VAMP-8 showed the most efficient liposome-liposome fusogenic activity. Liposomes with VAMP-7 exhibited poor fusogenic activity regardless of the syntaxin isoform.

Conclusion:

The core components of SNAP23, syntaxin-3, and VAMP-8 appear to be minimal machinery to induce membrane fusion, while VAMP-7 appears to be unessential for membrane fusion.