Botulinum toxin-based delivery platform (IMAGE) Boston Children's Hospital Caption The toxin-based delivery platform consists of the modified botulinum toxin at upper left (protease domain in gold, translocation domain in blue, and receptor-binding domain in purple) and the nanobody (the pink tag). When this nanobody-toxin fusion protein binds to the receptor (cyan) on the neuron surface, the cell takes it in through the process of endocytosis, corralling the fusion protein inside a vesicle (light green circle). The toxin's protease domain, carrying the nanobody, then crosses into the interior of the cell. Credit Sicai Zhang/Dong Lab, Boston Children's Hospital Usage Restrictions please credit as indicated. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.