N- to C-terminal SNARE complex assembly promotes rapid membrane fusion.
Assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) syntaxin 1, SNAP-25, and synaptobrevin 2 is thought to be the driving force for the exocytosis of synaptic vesicles. However, whereas exocytosis is triggered at a millisecond time scale, the SNARE-mediated fusion of liposomes requires hours for completion, which challenges the idea of a key role for SNAREs in the final steps of exocytosis. We found that liposome fusion was dramatically accelerated when a stabilized syntaxin/SNAP-25 acceptor complex was used. Thus, SNAREs do have the capacity to execute fusion at a speed required for neuronal secretion, demonstrating that the maintenance of acceptor complexes is a critical step in biological fusion reactions.
Pobbati
Ajaybabu V
AV
Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Stein
Alexander
A
Fasshauer
Dirk
D
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002942:Circular Dichroism; D019281:Dimerization; D005089:Exocytosis; D008081:Liposomes / Q000737:chemistry*; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D050765:Qa-SNARE Proteins / Q000737:chemistry / Q000378:metabolism*; D050683:R-SNARE Proteins / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D050825:Synaptosomal-Associated Protein 25 / Q000737:chemistry / Q000378:metabolism*
D008081:Liposomes; D010446:Peptide Fragments; D050765:Qa-SNARE Proteins; D050683:R-SNARE Proteins; D050825:Synaptosomal-Associated Protein 25