Abstract
Exosomes are small secretory vesicles (50-150 nm in diameter) of endocytic origin that have been recently identified as a novel intercellular communication pathway. They carry select cargo that impact the recipient cell’s metabolism and signaling pathways. The tissue-specificity of targeting and intracellular trafficking after uptake to the target cell are not fully understood and likely involve novel molecular cross-talk. Given that cultured tissue cells are used for the majority of exosome research (out of necessity), the Drosophila melanogaster larval neuromuscular junction (NMJ) offers a truly unique in vivo experimental system to address the biology of exosomes including their formation, release, uptake and trafficking. Here, I identify the membrane remodeling protein Amphiphysin as required for exosome trafficking in the recipient muscle cell. Furthermore, I show that the v-SNARE Ykt6 plays a role in neuronal exosome release. Additionally, I provide evidence that suggests a cargo-dependent exosome trafficking mechanism in the recipient muscle cells. Finally, I also developed a split-GFP reporter system to visualize post-synaptic exosomal trafficking and describe its in vivo application.