eLife (Jul 2018)

NSF-mediated disassembly of on- and off-pathway SNARE complexes and inhibition by complexin

  • Ucheor B Choi,
  • Minglei Zhao,
  • K Ian White,
  • Richard A Pfuetzner,
  • Luis Esquivies,
  • Qiangjun Zhou,
  • Axel T Brunger

DOI
https://doi.org/10.7554/eLife.36497
Journal volume & issue
Vol. 7

Abstract

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SNARE complex disassembly by the ATPase NSF is essential for neurotransmitter release and other membrane trafficking processes. We developed a single-molecule FRET assay to monitor repeated rounds of NSF-mediated disassembly and reassembly of individual SNARE complexes. For ternary neuronal SNARE complexes, disassembly proceeds in a single step within 100 msec. We observed short- (<0.32 s) and long-lived (≥0.32 s) disassembled states. The long-lived states represent fully disassembled SNARE complex, while the short-lived states correspond to failed disassembly or immediate reassembly. Either high ionic strength or decreased αSNAP concentration reduces the disassembly rate while increasing the frequency of short-lived states. NSF is also capable of disassembling anti-parallel ternary SNARE complexes, implicating it in quality control. Finally, complexin-1 competes with αSNAP binding to the SNARE complex; addition of complexin-1 has an effect similar to that of decreasing the αSNAP concentration, possibly differentially regulating cis and trans SNARE complexes disassembly.

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