A mutated form of the huntingtin protein disrupts the normal movement of vesicles holding HT and Rab4. This leads to defects in synapses, resulting in movement abnormalities and lifespan decreases in fruit fly larvae. Findings suggest Rab4 could be a novel therapeutic target for the early intervention of Huntington's disease, before the neuronal loss and behavioral deficits associated with the neurodegenerative disorder.