Sensory deficit screen identifies nsf mutation that differentially affects SNARE recycling and quality control

The AAA+ NSF complex is responsible for SNARE complex disassembly both before and after membrane fusion. Loss of NSF function results in pronounced developmental and degenerative defects. In a genetic screen for sensory deficits in zebrafish, we identified a mutation in nsf, I209N, that impairs hearing and balance in a dosage-dependent manner without accompanying defects in motility, myelination, and innervation. In vitro experiments demonstrate that while the I209N NSF protein recognizes SNARE complexes, the effects on disassembly are dependent upon the type of SNARE complex and I209N concentration. Higher levels of I209N protein produce a modest decrease in binary (syntaxin-SNAP-25) SNARE complex disassembly and residual ternary (syntaxin-1A-SNAP-25-synaptobrevin-2) disassembly, whereas at lower concentrations binary disassembly activity is strongly reduced and ternary disassembly activity is absent. Our study suggests that the differential effect on disassembly of SNARE complexes leads to selective effects on NSF-mediated membrane trafficking and auditory/vestibular function. [Display omitted] •Hypomorphic nsf mutation causes selective effects on sensorineural development and function•I209N mutation causes reduced precision and recovery of activity at hair-cell synapses•I209N mutation has differential effects on pre- and post-fusion SNARE complex disassembly•Quality control of binary SNARE complexes is critical for neurodevelopment Gao et al. combine forward genetics with biochemical analysis to provide mechanistic insight into a sensory deficit. Both in vivo and in vitro data highlight the differential effect of the I209N mutation on development and SNARE disassembly, indicating a key role for quality control by NSF in a biological context.