Expression of Rab5Scer\UAS.cEa in border cells, driven by Scer\GAL4slbo.2.6, induces a 5% increase in the number of egg chambers with an apical cap. Micro caps are seen less frequently than in wild-type egg chambers.
Rab5Scer\UAS.cEa, under the regulation of Scer\GAL4elav-C155 does not significantly alter the synaptic area, nor the active zone density of presynaptic terminals, implying that the total number of active zones is normal. The mean quantal content, however, is significantly increased by 1.74 times in Rab5Scer\UAS.cEa mutants compared to wild-type. Because the number of docked vesicles and the spontaneous release rate is normal, the higher quantal content indicates that elevated levels of Rab5 function leads to an increased probability of Ca2+-triggered synaptic vesicle release. Rab5Scer\UAS.cEa; Scer\GAL4elav-C155 larvae have expanded endosomal structures at pre-synaptic termini, producing large tubular structures and multivesicular bodies and only 1-3 endosomal structures per synaptic bouton.