Forming synaptic connections of the appropriate strength between specific neurons is crucial for constructing neural circuits to control behavior. A recent paper in Neural Development describes the use of a synapse-specific label in Caenorhabditis elegans to implicate local UNC-6/netrin signaling in this developmental process. Thus, as well as their well known roles in cell migration and axon guidance, UNC-6/netrin signals distinguish an appropriate synaptic partner from other potential targets.
J R. Park, P L. Knezevich, W Wung, S N. O'Hanlon, A Goyal, K L. Benedetti, B J. Barsi-Rhyne, M Raman, N Mock, M Bremer, and Miri VanHoven. "A conserved juxtacrine signal regulates synaptic partner recognition in C. elegans" Neural Development (2011): 28. DOI: 10.1038/nn.3065