Membrane scission is required for the formation of vesicles or ‘exosomes’ that can travel in the bloodstream and in the space between cells to mediate cell-to-cell communication (see left corner image showing exosomes (green dots) in the bloodstream of a live fish). Formation of exosome vesicles is severely reduced in zebrafish vps4a mutants that share features with human VPS4A patients. The Nicolson lab study demonstrates that sensory cues such as sound excite the auditory pathway in mutant fish, however, auditory signals fail to fully activate command neurons in the brain that control upright posture and movements. These results suggest that this sensorimotor circuit is particularly sensitive to the loss of vps4a function. Currently many clinical trials are testing the use of exosomes for therapy and our results suggest that VPS4A patients may benefit from this type of treatment.