Using the cellular model of neuronal atrophy caused by DYNC1I1 deficiency, we are able to identify that RAS-RAF-MEK signaling, but not PI3K-AKT signaling, protects neurons against dendritic atrophy in primary hippocampal neurons, and reveals that RAS-RAF signaling activates MEK-dependent protective autophagy. Here, DYNC1I1 is linked to Atrophy.