| Abstract No.: | A-B1048 |
| Country: | Canada |
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| Title: | SCRIBBLE INTERACTS WITH BETA-CATENIN TO REGULATE THE LOCALIZATION OF SYNAPTIC VESICLES |
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| Authors/Affiliations: | 1 Yu Sun*; 1 Elieen Yoshida; 1 Mytyl Aiga; 1 Shernaz Bamji;
1 University of British Columbia, Vancouver, BC, Canada
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| Content: | Objectives: We have previously demonstrated that cadherin/beta-catenin complexes cluster synaptic vesicles at presynaptic sites. A detailed analysis of catenin functional domains revealed that the PDZ-binding motif is essential for vesicle localization. Scribble, a PDZ domain-containing protein, has been shown to regulate vesicle localization at neuromuscular junctions in Drosophila. In the present study, we examined whether or not scribble localizes synaptic vesicles to nascent synapses in cultured hippocampal neurons.
Materials and Methods: Immunohistochemistry was used to examine the localization of scribble in cultured hippocampal neurons. Co-immunoprecipitation was used to identify the interaction between scribble and beta-catenin. An RNA interference approach was used to attenuate scribble expression and examine the role of scribble on regulation of vesicle localization.
Results: Scribble and beta-catenin are co-localized at synapses and can be co-immunoprecipitated from neuronal lysates, indicating an interaction between scribble and catenin at the synapse. Using an RNA interference approach, we demonstrate that scribble is essential for the clustering of synaptic vesicles at synapses. Indeed, in scribble mutant cells, there is a diffuse distribution of synaptic vesicles along the axon. Despite this, synapse number and the distribution of the presynaptic active zone protein, bassoon, remain unchanged. These effects largely phenocopy those observed following ablation of beta-catenin. In addition, we show that loss of beta-catenin disrupts scribble localization in primary neurons but that the localization of beta-catenin is not dependent on scribble.
Conclusion: Our data supports a model by which scribble functions downstream of beta-catenin to cluster synaptic vesicles at developing synapses.
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