Untersuchungen zur Bedeutung der verschiedenen Wnt-Signalkaskaden und deren zentrale Moleküle in der Synaptogenese
Final Report Abstract
Wnt/wg signaling contributes to the development of neuronal synapses, including the Drosophila neuromuscular junction. Loss of wingless (wg) function alters the number and structure of boutons at this model synapse. Examining Wnt/wg signaling pathways, we find that a distinct pathway operates presynaptically in the motorneuron and can account for many of the effects of Wg at this synapse. This pathway includes the canonical elements arrow/LRP, dishevelled, and the glycogen synthase kinase shaggy (GSK3) and regulates the formation of microtubule loops within synaptic boutons as well as the number of synaptic boutons. This pathway, however, appears to be independent of ß-catenin signaling and the transcriptional regulation that is most frequently downstream of this pathway. Instead, inhibition of shaggy is likely to act locally. This pathway thus provides a parallel mechanism to the postsynaptic activation of Fz receptors and indicates that synaptic development results from the bidirectional influence of Wg on both pre- and postsynaptic structures via distinct intracellular pathways.
