Previous studies have shown that both the Fasciclin II (Fas II) cell a
dhesion molecule and the Shaker potassium channel are localized at the
Drosophila neuromuscular junction, where they function in the growth
and plasticity of the synapse. Here, we use the GAL4-UAS system to dri
ve expression of the chimeric proteins CD8-Fas II and CD8-Shaker and s
how that the C-terminal sequences of both Fas II and Shaker are necess
ary and sufficient to drive the synaptic localization of a heterologou
s protein. Moreover, we show that the PDZ-containing protein Discs-Lar
ge (Dlg) controls the localization of these proteins, most likely thro
ugh a direct interaction with their C-terminal amino acids. Finally, t
ransient expression studies show that the pathway these proteins take
to the synapse involves either an active clustering or a selective sta
bilization in the synaptic membrane.