During development and adult tissue homeostasis cells integrate intrinsic and extrinsic cues into signals that are shared with the surrounding cell population. These signals can synchronize or desynchronize cellular behavior and coordinate position, fate or destination of individual cells. Alan Turings’ concept of morphogens gradients has been intensively investigated for its role in pattern formation. The molecular form of these gradients was long considered to be secreted protein ligands, which activate different signaling pathways on receiving cells. Aberrant activation of these signaling pathways leads to the progression of cancer. However, increasing evidence suggests that extracellular vesicles (EVs) are the carriers of such messages. They are a heterogeneous population of membrane particles released into the extracellular space in vitro and in vivo. But how these structures are signaling from one cell to another remains elusive. In the proposed program we will systematically study the secretion and signaling of EVs in the context of cell migration in tumor cells and in vivo in Drosophila melanogaster. We will focus on the cell biological mechanisms of EVs release. Specifically, we want to understand cellular processes that influence and regulate their release and investigate the dynamics and biogenesis of subpopulations of EVs. We will focus on the composition of signaling EVs, which pathways they activate in cells and deduce how EV signals are decoded in the context of directed cell migration. Altogether our research aims to provide a deep insight into cellular communication via EVs. Understanding their biological role in vivo, their transmission and reception will add a new layer to extracellular signaling pathways. By defining the aberrant conditions as well as mechanisms of signaling of EVs we will help to find possible biomarkers and targets for therapeutic manipulation.