Neurotransmitter release relies on a series of synaptic vesicle trafficking
reactions. We have determined the molecular basis of these reactions by mi
croinjecting, into 'giant' nerve terminals of squid, probes that interfere
with presynaptic proteins. These probes affect neurotransmitter release and
disrupt nerve terminal structure. From the nature of these lesions, it is
possible to deduce the roles of individual proteins in specific vesicle tra
fficking reactions. This approach has revealed the function of more than a
dozen presynaptic proteins and we hypothesize that neurotransmitter release
requires the coordinated action of perhaps 50-100 proteins.