SYNAPTIC CLUSTERING OF FASCICLIN-II AND SHAKER - ESSENTIAL TARGETING SEQUENCES AND ROLE OF DLG

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.