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Defects in synaptic vesicle docking in unc-18 mutants.

Robby M Weimer·Janet E Richmond·Warren S Davis·Gayla Hadwiger·Michael L Nonet·Erik M Jorgensen
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Abstract

Sec1-related proteins function in most, if not all, membrane trafficking pathways in eukaryotic cells. The Sec1-related protein required in neurons for synaptic vesicle exocytosis is UNC-18. Several models for UNC-18 function during vesicle exocytosis are under consideration. We have tested these models by characterizing unc-18 mutants of the nematode Caenorhabditis elegans. In the absence of UNC-18, the size of the readily releasable pool is severely reduced. Our results show that the near absence of fusion-competent vesicles is not caused by a reduction in syntaxin levels, by a mislocalization of syntaxin, by a defect in fusion or by a failure to open syntaxin during priming. Rather, we found a reduction of docked vesicles at the active zone in unc-18 mutants, suggesting that UNC-18 functions, directly or indirectly, as a facilitator of vesicle docking.

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AnimalsCaenorhabditis elegansCaenorhabditis elegans ProteinsCarrier ProteinsCell DifferentiationElectric StimulationExocytosisGreen Fluorescent ProteinsLuminescent ProteinsMembrane FusionMembrane ProteinsMicroscopy, ElectronModels, AnimalMotor NeuronsMutationNeuromuscular JunctionPhosphoproteinsPresynaptic TerminalsProtein TransportQa-SNARE ProteinsR-SNARE ProteinsReceptors, GABARecombinant Fusion ProteinsSynaptic TransmissionSynaptic VesiclesVesicular Transport Proteinsgamma-Aminobutyric AcidJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Robby M Weimer, Janet E Richmond, Warren S Davis, Gayla Hadwiger, Michael L Nonet, Erik M Jorgensen. 2003-09-14. Defects in synaptic vesicle docking in unc-18 mutants.. https://doi.org/10.1038/nn1118

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