A Charcot-Marie-Tooth-associated dynamin mutation causes peripheral neuropathy-like phenotypes via Patronin/CAMSAP-dependent microtubule stabilization

Dynamin-2 mutations are associated with Charcot-Marie-Tooth (CMT) neuropathy; however, how these mutations affect neuronal function in vivo remains unclear. Here, we generated a Drosophila model carrying a CRISPR/Cas9-mediated knock-in of the shi549{Delta}3 mutation, corresponding to the human dynamin-2-551{Delta}3 variant, and examined its physiological and cellular consequences. The shi549{Delta}3 mutants exhibited progressive motor impairment across multiple genetic conditions. At the neuromuscular junction, the mutation caused synaptic overgrowth accompanied by excessive microtubule stabilization, including increased Futsch-positive loop structures and bouton numbers. Genetic interaction analysis revealed that reduction of Patronin, the Drosophila homolog of mammalian CAMSAPs, partially suppressed lethality and motor defects, linking microtubule stabilization to neuronal dysfunction in vivo. Consistently, CAMSAP2 knockdown in mammalian cells attenuated dynamin-2-induced microtubule acetylation, supporting a conserved mechanism. Together, these findings identify dysregulated microtubule stabilization as a key mechanism underlying neuropathy-like phenotypes caused by a CMT-associated dynamin mutation in vivo.