Is Wnt a Synaptomorphogen?

Science's STKE  28 Aug 2007:
Vol. 2007, Issue 401, pp. tw311
DOI: 10.1126/stke.4012007tw311

Wnts, which are a class of ligands, are involved in many cellular processes and have been previously implicated as prosynaptogenic factors. Klassen and Shen show that the formation of synapses by the motor neuron DA9 is inhibited by a Wnt signaling pathway in Caenorhabditis elegans involving the Wnts LIN-44 and EGL-20, the Wnt receptor LIN-17, and the intracellular signaling component DSH-1. The pathway appeared to be a noncanonical one, as mutations in genes encoding participants in the Wnt-β-catenin pathway, the planar cell polarity pathway, and the Wnt-calcium signaling pathway did not cause the formation of synapses in regions that were asynaptic in wild-type worms. As discussed by Davis and Ghosh, it will be interesting to determine what the mechanism of Wnt regulation of synapse formation is and whether there is a dose-dependent effect that would classify Wnt as a synaptomorphogen.

M. P. Klassen, J. Shen, Wnt signaling positions neuromuscular connectivity by inhibiting synapse formation in C. elegans. Cell 130, 704-716 (2007). [PubMed]

E. Davis, A. Ghosh, Should I stay or should I go: Wnt signals at the synapse. Cell 130, 593-596 (2007). [PubMed]