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

ABSTRACT: 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 ?SNAP 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 ?SNAP binding to the SNARE complex; addition of complexin-1 has an effect similar to that of decreasing the ?SNAP concentration, possibly differentially regulating cis and trans SNARE complexes disassembly.

SUBMITTER: Choi UB 

PROVIDER: S-EPMC6130971 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature