Formation of Golgi-Derived Active Zone Precursor Vesicles

Department of Psychiatry and Behavioral Sciences, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California 94304-5485, USA.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.75). 08/2012; 32(32):11095-108. DOI: 10.1523/JNEUROSCI.0195-12.2012
Source: PubMed

ABSTRACT Vesicular trafficking of presynaptic and postsynaptic components is emerging as a general cellular mechanism for the delivery of scaffold proteins, ion channels, and receptors to nascent and mature synapses. However, the molecular mechanisms leading to the selection of cargos and their differential transport to subneuronal compartments are not well understood, in part because of the mixing of cargos at the plasma membrane and/or within endosomal compartments. In the present study, we have explored the cellular mechanisms of active zone precursor vesicle assembly at the Golgi in dissociated hippocampal neurons of Rattus norvegicus. Our studies show that Piccolo, Bassoon, and ELKS2/CAST exit the trans-Golgi network on a common vesicle that requires Piccolo and Bassoon for its proper assembly. In contrast, Munc13 and synaptic vesicle proteins use distinct sets of Golgi-derived transport vesicles, while RIM1α associates with vesicular membranes in a post-Golgi compartment. Furthermore, Piccolo and Bassoon are necessary for ELKS2/CAST to leave the Golgi in association with vesicles, and a core domain of Bassoon is sufficient to facilitate formation of these vesicles. While these findings support emerging principles regarding active zone differentiation, the cellular and molecular analyses reported here also indicate that the Piccolo-Bassoon transport vesicles leaving the Golgi may undergo further changes in protein composition before arriving at synaptic sites.

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    • "Bassoon and its paralogue Piccolo are transported into the axon on membranous organelles [25], [40], [41], [42]. To check whether the defect in supply of mobile GFP-BsnS2845A contributes to observed decreased recovery we analyzed the mobility properties of fluorescently-labeled vesicles in neurons transfected with wt and mutant constructs. "
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