Protocadherins: not just neuron glue, more too!

Selective fasciculation, in which axons navigate toward their targets along preexisting "pioneer" axons, requires specific cell-cell contacts to ensure proper target innervation. In this issue of Developmental Cell, Hayashi et al. (2014) show that the adhesion molecule Protocadherin-17 regulates selective fasciculation by promoting growth, rather than adhesion, of amygdala axons.