Exosome biogenesis in arthropods: conserved mechanisms, experimental evidence, and emerging directions

Extracellular vesicles (EVs) are nanoscale, lipid-bound structures released by cells across all domains of life. Once viewed as a means for discarding unwanted cellular components, they are now understood to be central mediators of intercellular communication. Much of what is known about EVs comes from mammalian systems, where extensive work has defined the major EV subtypes and the mechanisms that generate exosomes. These findings continue to serve as the primary reference for interpreting EV biology in other organisms. EVs have been isolated from diverse arthropods, including a few insect and tick species, yet the molecular pathways that produce them remain less characterized. Current evidence from Drosophila, mosquito cell lines, and tick systems shows that many of the core components driving exosome biogenesis in mammals, including ESCRT complexes, tetraspanins, lipid-modifying enzymes, Rab GTPases, and SNARE proteins, are present and, in several cases, experimentally validated in arthropods. These findings point to broad conservation of exosome biogenesis across taxa, while also highlighting key caveats, with most conclusions relying on only a small number of model systems. The definitions of EV subtypes remain unclear in many arthropods, and alternative EV biogenesis pathways have received little attention. Future studies that incorporate non-model species, apply rigorous EV characterization standards, and explore the roles of various EV subtypes will clarify how these pathways operate across arthropod lineages and how they differ from well-studied mammalian systems.