Figure 1.

Suppression of Aplip1 (Jip1) overexpression-induced vesicle accumulation in axons by a ubiquitin hydrolase and a MAPKKK.

The distribution of a synaptic vesicle glutamate transporter, DVGLUT, is shown in nerves of third instar Drosophila larvae by immunostaining and confocal fluorescence microscopy. Each nerve contains 60-80 motor and sensory axons. Up arrows reflect GAL4-UAS driven expression of transgenes. (A) Wild-type nerves (wt) with DVGLUT in small punctae consistent with its concentration in membranes of axonal transport vesicles. (B to D) Expression of a transgenic FLAG-tagged Aplip1 (Aplip1(F)) was induced in neurons with an elav-GAL4 driver. (B) Over-expression of Aplip1 caused dramatic accumulation of DVGLUT, consistent with organelle accumulation in focal axonal swellings [8]. (C) Suppression of Aplip1-induced accumulation by transgenic co-overexpression of faf, a ubiquitin hydrolase. (D) A 50% reduction of the gene dosage for a MAPKKK (wnd) prevented faf suppression of Aplip1. (E to G) Expression of a transgenic GFP-tagged Aplip1, Aplip1(G), was induced in motoneurons with the OK6-Gal4 driver. (E) DVGLUT accumulations caused by overexpression of Aplip1. (F) Suppression of the accumulations by co-expression of wild-type wnd. (G) No suppression of the accumulations by co-expression of a kinase-dead version of wnd (wnd^KD). The wnd^KD transgene was expressed at a higher level than the wild-type wnd transgene (not shown). Full genotypes are noted in Table S1 (Scale bar = 20μm).