Intermediates of SNARE-mediated membrane fusion – Niels Bohr Institute - University of Copenhagen

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Intermediates of SNARE-mediated membrane fusion

Cellular membrane fusion is thought to proceed through intermediates including docking of apposed lipid bilayers, merging of proximal leaflets to form a hemifusion diaphragm, and fusion pore opening. A membrane-bridging four-helix complex of soluble N-ethylmaleimide–sensitive factor attachment protein receptors (SNAREs) mediates fusion. However, how assembly of the SNARE complex generates docking and other fusion intermediates is unknown. In this presentation I will discuss how we used a cell-free reaction to identify intermediates visually and then arrest the SNARE fusion machinery when fusion was about to begin. We found that partial and directional assembly of SNAREs tightly docked bilayers, but efficient fusion and an extended form of hemifusion required assembly beyond the core complex to the membrane-connecting linkers. We propose that straining of lipids at the edges of an extended docking zone initiates fusion.

Talk by Mathias Hernandes Postdoctoral Fellow, Max Planck Institute for Biophysical Chemistry, Department of Neurobiology Gottingen, Germany