Observing the molecular machinery of exocytosis

Synaptic vesicle exocytosis is a fundamental process for life which is behind neurotransmitter release at nerve terminals. Thus, dysfunctional exocytosis has been associated with various conditions, including schizophrenia and epilepsy. SNARE proteins are the machinery that drives exocytosis which makes them particularly good targets for studying what happens at the cell level using standard confocal and Super-Resolution microscopy techniques. Additionally, while much is known about SNAREs and associated proteins, their exact spatiotemporal organisation immediately before and after exocytosis is currently unknown.
Meanwhile, Botulinum Neurotoxins (BoNTs) are among some of the lethal substances known to man. This toxicity is due to their natural ability to bind and specifically cleave SNARE proteins. This causes Botulism, a condition characterised by impairment of neurotransmission and paralysis.
Since BoNTs naturally bind and specifically target neuronal SNAREs, our research group has been looking to re-engineer BoNTs in a way that these may still bind while not cleaving their target SNAREs. This would allow for the use of BoNTs as highly specific labelling agents of SNARE proteins to help dissect the cell dynamics that drive exocytosis.